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UBC Theses and Dissertations

A proposed earth science curriculum for grades 8 and 10 in British Columbia high schools Borthwick, Alistair John 1979

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A PROPOSED EARTH SCIENCE CURRICULUM FOR GRADES 8 AND 10 • I N BRITISH COLUMBIA HIGH SCHOOLS . by ALISTAIR JOHN BORTHWICK B.Sc., The U n i v e r s i t y of B r i t i s h Columbia, 196? A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS ."' - ' " '." .', ' i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OP SCIENCE EDUCATION We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF.BRITISH COLUMBIA October 1 9 7 9 © A l i s t a i r John Borthwick,. 1 9 7 9 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department n f S c i e n c e E d u c a t i o n The U n i v e r s i t y o f B r i t i s h Columbia 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 A l i s t a i r J . Borthwick BP 75-51 I E i i ABSTRACT , D u r i n g t h e p a s t two d e c a d e s , e v i d e n c e has been m o u n t i n g i n f a v o u r o f t h e t h e o r y o f p l a t e t e c t o n i c s . A t t h e p r e s e n t t i m e , t h e e a r t h s c i e n c e s e c t i o n s o f t h e j u n i o r s e c o n d a r y s c h o o l s c i e n c e c u r r i c u l u m p r e s c r i b e d by t h e B r i t i s h C o l u m b i a M i n i s t r y o f E d u c a t i o n a r e d e f i c i e n t i n i n f o r m a t i o n r e l a t i n g t o t h i s t h e o r y . The p r e s e n t c u r r i c u l u m i s a l s o d e f i c i e n t i n examples and e x p l a n a t i o n s o f t h e e a r t h s c i e n c e s as t h e y r e l a t e s p e c i f i c a l l y t o B r i t i s h C o l u m b i a . T h i s t h e s i s a t t e m p t s t o r e c t i f y a need p e r c e i v e d by t h e a u t h o r , t h e B.C. M i n i s t r y o f E d u c a t i o n , and P r e n t i c e -H a l l o f Canada L t d . f o r a new e a r t h s c i e n c e program, by p r o p o s i n g a r e v i s e d c u r r i c u l u m i n c o r p o r a t i n g p l a t e t e c t o n i c t h e o r y , and b a s e d f i r m l y upon B.C. r e g i o n a l phenomena. The r e v i s i o n i s d e s i g n e d i n s u c h a way t h a t i t may be p u t t o immediate use by a p r a c t i s i n g c l a s s r o o m t e a c h e r . W i t h t h e a i d o f t h e s u p p l e m e n t a r y T e a c h e r s ' G u i d e , even an i n e x p e r i e n c e d t e a c h e r w i t h m i n i m a l knowledge of e a r t h s c i e n c e w o u l d p r o b a b l y be a b l e t o i m p l e m e n t t h e p r o p o s e d c u r r i c u l u m s u c c e s s f u l l y . The p r o p o s e d c u r r i c u l u m i s d i v i d e d i n t o two p a r t s . The f i r s t o f . t h e s e , i n t e n d e d f o r s t u d e n t s i n Grade 8, c o v e r s t h e g r a d a t i o n a l a s p e c t s o f g e o l o g y . The s e c o n d p a r t , s u i t a b l e f o r g r a d e 1 0 s t u d e n t s , c o v e r s d i a s t r o p h i s m , v o l c a n i s m , p l a t e t e c t o n i c s , and e a r t h h i s t o r y . B r i e f e x c u r s i o n s a r e made i n t o mapping, r o c k and m i n e r a l i d e n t i f i c a t i o n , and p a l e o n t o l o g y . I n b o t h p a r t s , t h e t e a c h i n g method u s e d i s t h a t o f " g u i d e d d i s c o v e r y " , i n v o l v i n g a m i x t u r e o f s t u d e n t l a b o r a t o r y e x e r c i s e s and i i i d e m o n s t r a t i o n s , s u p p l e m e n t e d by i n f o r m a t i o n a l n a r r a t i v e s . The p r o p o s e d c u r r i c u l u m c o n t a i n s a number o f e l e m e n t s u n i q u e t o t h e t e a c h i n g o f e a r t h science,. These range f r o m t h e a p p l i c a t i o n o f new s t r a t e g i e s t o t h e t e a c h i n g o f w e l l known t o p i c s , t o t h e i n c l u s i o n o f m a t e r i a l n o t f o u n d i n any p r e s e n t l y e x i s t i n g e a r t h s c i e n c e c u r r i c u l u m . I n t h e l a t t e r c a s e , much of t h i s m a t e r i a l has been so r e c e n t l y d i s c o v e r e d t h a t i t has n o t y e t f o u n d i t s way i n t o j u n i o r s e c o n d a r y c u r r i c u l a , o r i s o f s u c h s t r o n g B.C. r e g i o n a l i n t e r e s t so as t o p r e c l u d e i t s i n c l u s i o n i n c u r r i c u l a i n t e n d e d f o r C a n a d i a n n a t i o n a l o r N o r t h A m e r i c a n c o n t i n e n t a l u s a g e . E a r l y d r a f t s o f t h e p r o p o s e d c u r r i c u l u m were c l a s s r o o m t e s t e d by a number o f p r a c t i s i n g t e a c h e r s i n s e v e r a l j u n i o r s e c o n d a r y s c h o o l s o v e r a p e r i o d of two y e a r s . The r e s u l t s o f t h i s e x t e n s i v e t e s t i n g were i n c o r p o r a t e d i n t o t h e p r e s e n t f o r m o f t h e p r o p o s e d c u r r i c u l u m . I n c o n c l u s i o n , i t a p p e a r s t h a t t h i s p r o p o s e d e a r t h s c i e n c e c u r r i c u l u m i s s u i t a b l e f o r s t u d e n t s i n g r a d e s 8 and 10 o f t h e B r i t i s h C o l u m b i a s c h o o l s y s t e m . i v CONTENTS A b s t r a c t C o n t e n t s . F i g u r e s I n t r o d u c t i o n Statement of Purpose R a t i o n a l e Methods P h i l o s o p h i c a l B a s i s Course O b j e c t i v e s P r o p o s e d C u r r i c u l u m G e n e r a l O u t l i n e S e l e c t e d A r e a s , P a r t 1 S e l e c t e d A r e a s , P a r t 2 D i s c u s s i o n G e n e r a l C o n c l u s i o n T e a c h e r s ' Manual B i b l i o g r a p h y Addendum L I S T OF FIGURES 1 a . L a y e r s of t h e E a r t h 1 b . . C u r r e n t s w i t h i n t h e E a r t h 1 c . The E a r t h i n the p a s t 1 d . Sandstone 2 . C onglomerate 3 . G r a n i t e 4. B a s a l t 5 . G n e i s s 6 a C o a l and s h a l e , E l l e s m e r e I s l a n d 6b. The r o c k c y c l e 7 . G e o l o g i c map o f t h e P o r t Moody a r e a 8. O u t l i n e map f o r I n v e s t i g a t i o n 7 9 . O u t l i n e map o f t h e F r a s e r R i v e r d e l t a 1 0 . S a t e l l i t e p h o t o g r a p h o f F r a s e r d e l t a 1 1 . D e l t a f r o n t 1 2 . N i l e d e l t a 1 3 . MacKenzie d e l t a 14. Squamish d e l t a 1 5 . F l o o d p l a i n 16. O u t l i n e o f d e l t a f r o n t 1 7 . P i t t R i v e r d e l t a 18. T r i l o b i t e s 1 9 . Lambeosaurus 2 0 . O u t l i n e maps of Canada 2 1 . S i d e v i e w of a g l a c i e r 2 2 . C r e v a s s e 2 3 . A l p i n e g l a c i e r s v i •' 24-. Athabaska G l a c i e r snout. 77 25. V a l l e y g l a c i e r 79 26. Emerald g l a c i e r 79 2 7 . Medial moraines on Coronation G l a c i e r 80 28. G l a c i a l landforms 82 29. L e c k i e Creek v a l l e y 82 3 0 . Cirque 84-3 1 . G l a c i a l landscape. 84-32. F i o r d 85 33* Raised beaches . 85 34-. G l a c i a l l y p o l i s h e d rocks 86 35. T r i l o b i t e s 96 36. Shark t o o t h 96 37. Ammonite 97 38. C r i n o i d stems 97 39• Brachiopods 98 4-0. Pelecypods 98 4-1. Gastropod 99 4-2. R e p t i l e v e r t e b r a 99 4-3. R e p t i l e bone weathering out of rock 100 4-4-. Carbonized leaves 100 4-5. S i l i c i f i e d wood 104-4-6. F o s s i l f o r m a t i o n 104-4-7. Canyon . 1 0 6 4-8. F o s s i l sketches 106 4-9. O u t l i n e map of B.C. 106 50. Graph axes 114-5 1 . Graph axes 114-v i i 5 2 . Hot s p r i n g o p e r a t i o n 1 1 9 53. Banff hot s p r i n g . 1 1 9 5 4 - . Use of geothermal water 120 5 5 * Cenozoic volcanoes of B.C. 124-56. Mount E d z i z a 124-57. Eve Cone 125 58. Mount G a r i b a l d i and the Table 125 59. The B a r r i e r 126 60. G a r i b a l d i Lake 126 61. Black Tusk 1 2 7 62. Black Tusk 128 63. Cinder Cone 128 64-. Mount Baker _ 129 65. C r a t e r , Mount Baker 129 66. F a u l t , Hanning Bay 136 67. F a u l t , Hanning Bay 136 68. F a u l t zone, Hawaii 1 3 7 69. Road damaged by f a u l t i n g 1 3 7 70. M e r c a l l i i n t e n s i t i e s , south Okanagan , 14-1 7 1 . B u i l d i n g s damaged by an earthquake 14-3 72. School damaged by an earthquake 14-3 7 3 « Earthquake damage i n Anchorage 144 74-a. Railway damaged by an earthquake 144-74-b. Canadian earthquake hazard zones 14-7 '74-c. Demonstrating a P-wave 14-8 7 5 « Demonstrating an S-wave 14-8 76. Seismograms 1 5 0 7 7 . P-wave v i i i 78. P-wave and S-v/ave 151 7 9 . T r a v e l time graph 154-80. Earthquake r e c o r d i n g s t a t i o n s ' 1 5 5 31. Tsunami damage 1 5 9 82. Tsunami damage 1 5 9 83. World map 166 84-. A l f r e d Wegener's map of the world p r i o r to c o n t i n e n t a l d r i f t 166 8 5 . Wegener's model of c o n t i n e n t a l d r i f t 1 6 9 86. P l a t e motion 1 6 9 8 7 . Wegener's map of Pangea 1 7 0 8 8 . P l a t e t e c t o n i c map of Pangea 1 7 0 8 9 . Major p l a t e s 1 7 1 9 0 . Landsat photograph of I n d i a n p l a i n and the Himalayas 1 7 2 9 1 . San Andreas f a u l t 1 7 6 9 2 . San Andreas f a u l t l o c a t i o n 1 7 6 9 3 . San Andreas f a u l t , C a r r i z o P l a i n 1 7 7 9 4 - . Landsat photograph of San Andreas f a u l t 1 7 8 ; 9 5 . F a u l t l o c a t i o n s near San F r a n c i s c o 1 7 9 9 6 . C o a s t a l f e a t u r e s of B.C. 184-9 7 . P l a t e movement near the B.C. coast 184-98. B.C. c o a l f i e l d s 188 9 9 - B.C. mining operations 189 1 0 0 . P r o f i l e from I n v e s t i g a t i o n 1 2 2 0 7 1 0 1 a . H y d r o l o g i c c y c l e apparatus 2 1 0 1 0 1 b . Small s c a l e map • 2 9 0 1 0 2 . Medium s c a l e map 2 9 0 i x 103. Large s c a l e map 2 9 1 104. Drawing a p r o f i l e 296 105- O u t l i n e f o r p r o f i l e 2 9 7 105. P h y s i c a l weathering 299 10?.. Chemical weathering 299 108. B i o l o g i c a l weathering 300 1 0 9 . Water r e s e r v o i r s • 304 1 1 0 . F i l t e r i n g apparatus . 312 111. Braided stream 3 1 3 112. Canyon on the Athabaska R i v e r 3 1 6 1 1 3 . Yellowstone Canyon 3 1 7 114. F r a s e r Canyon . 3 1 3 1 1 5 . Bryce Canyon 3 1 9 116. F r a s e r V a l l e y 322 1 1 7 . Meandering R i v e r 322 118. P a r s n i p R i v e r 323 1 1 9 . L a n d s l i d e , T a k i n i .River 323 120. Frank S l i d e 3 3 7 121. Hope s l i d e 3 3 7 122. F o s s i l leaves : 339 123. Ammonite 339. 124. A l l o s a u r u s 3^3 1 2 5 . Tyrannosaurus 343 126. Iguanodon 344 1 2 7 . Camptosaurus 344 128. Diplodocus . . 3 ^ 5 1 2 9 . Rhamp.horh.ynchus " ' 345 .130. Pteranodon,. . 3^5 1 3 1 . Ank.ylosaurus 346 1 3 2 . E r y o p s ' ' . 34-6 1 3 3 . H o n o c l o n i u s 34-6 134. E o g y r i n u s 3 4 - 7 1 3 5 . B r a c h i o s a u r u s 3 4 - 7 1 3 6 . D i a e t r o d o n 3 4 7 1 3 7 . I c h t h y o s a u r u s .. ' . 3 4 - 8 1 3 8 . H esperosuchus 3 4 - 8 1 3 9 . E l a s r a o s a u r u s 3 4 - 8 140. C o q u i t l a m R i v e r f i e l d t r i p a r e a 3 5 5 141. N o r t h e r n f i e l d t r i p a r e a 3 6 0 142. S o u t h e r n f i e l d t r i p a r e a 3 6 1 143. Graph axes 3 6 6 144. E a r t h ' s c r u s t 3 6 6 145. R a d i o a c t i v e decay gr a p h 3 8 0 146. Human s k e l e t o n 3 8 3 147. Dimetrodon s k e l e t o n 3 8 4 148. F o r e l i m b s 3 8 5 149. M i l l e r ' s a p p a r a t u s 5 8 9 1 5 0 . L i m e s t o n e , s o u t h Wales 3 9 6 1 5 1 . Sandstone 3 9 6 1 5 2 . Conglomerate ' . 3 9 9 1 5 3 a . R i v e r mouth 3 9 9 1 5 5 b . O p e r a t i o n of a v o l c a n o 402 1 5 4 . . C i n d e r cone 4-02 1 5 5 . S t r a t o v o l c a n o 4 - 0 3 1 5 6 . Mauna Loa 4 - 0 3 1 5 7 . M e l t i n g wax 4-04 x i 1 5 3 . I n t e r n a l s t r u c t u r e of a s t r a t o v o l c a n o 404 1 5 9 . Mauna Kea 408 160., Mauna U l u 408 161. Mount G a r i b a l d i 409 162. V o l c a n o e s , c e n t r a l Ore gon, U.S.A. 409 163. Mount Newberry 410 164. Mauna U l u 410 .165- Mount B a k e r . 411 166. W i z a r d I s l a n d 411 167. C r a t e r Lake 412 168. Dyke 413 169. L a v a tube 414 1 7 0 . G i a n t ' s Causeway 4 1 5 1 7 1 . B l a c k sand beach 4 1 5 1 7 2 . F i s s u r e e r u p t i o n 416 1 7 3 . F l o o d l a v a s of B.C. . 4 1 7 1 7 4 . Olympus Mons 4 1 7 1 7 5 . Comparison of Olympus Mons and B.C. 418 176. O u t l i n e map of w o r l d 421 1 7 7 . B a s a l t 426 1 7 3 . G r a n i t e 426 1 7 9 . G n e i s s 427 180. Rock c y c l e 429 181. D e m o n s t r a t i n g i n e r t i a 432 182. Model s e i s m o g r a p h 432 183. O u t l i n e map of B.C. 436 184. O u t l i n e map of w o r l d 437 185. Graph f o r ocean f l o o r c r o s s - s e c t i o n 438 X X I 186. S t e e p n e s s e x a g g e r a t i o n of c r o s s - s e c t i o n 4 - 3 8 187. C o n t i n e n t a l o u t l i n e s 443 188. C o n t i n e n t a l , s h e l f o u t l i n e s 449 189. R e p r e s e n t a t i o n of l a v a l a y e r s 451 1 9 0 . R e p r e s e n t a t i o n of s p r e a d i n g - l a v a 451 1 9 1 . O u t l i n e :map of n o r t h A t l a n t i c Ocean . 456 1 9 2 . Former magnetic p o l e p o s i t i o n s 458 1 9 3 . F i t t i n g of p o l a r w a n d e r i n g c u r v e s 458 194. P l a t e s s l i d i n g 461 1 9 5 . C o n t i n e n t a l p l a t e s c o l l i d i n g 461 1 9 6 . C o n t i n e n t a l and o c e a n i c p l a t e s c o l l i d i n g 462 1 9 7 . O c e a n i c p l a t e s s p r e a d i n g 462 1 9 8 . G r i d f o r p l o t t i n g e a r t h q u a k e d a t a 463 1 9 9 . C l e a v a g e p a t t e r n s of m i n e r a l s 4 7 0 1 INTRODUCTION S t a t e m e n t o f P u r pose . T h i s p r o p o s e d c u r r i c u l u m i s a combined t e x t - b o o k and l a b o r a t o r y manual d e s i g n e d f o r j u n i o r h i g h s c h o o l s c i e n c e , whose f u n d a m e n t a l g o a l i s t o h e l p s t u d e n t s t o u n d e r s t a n d t h e o r i g i n o f t y p i c a l l a n d f o r m s f o u n d i n B r i t i s h C o l u m b i a , and t h e i r r e l a t i o n s h i p t o s i m i l a r s t r u c t u r e s i n o t h e r p a r t s o f t h e w o r l d . To t h i s end, t h e c u r r i c u l u m d e a l s w i t h b o t h t h e g r a d a t i o n a l and o r o g e n i c a s p e c t s o f g e o l o g y , c o n c e n t r a t i n g upon m o d i f i c a t i o n o f t h e l o c a l l a n d s c a p e by w a t e r and i c e , and upon g r o s s d e f o r m a t i o n o f t h e E a r t h ' s s u r f a c e by t h e f o r c e s o f p l a t e t e c t o n i c s . R a t i o n a l e P h i l o s o p h e r s o f s c i e n c e - n o t a b l y T. S. Kuhn - have p o i n t e d o u t t h a t m ajor s c i e n t i f i c advances f r e q u e n t l y o c c u r as r e o r g a n i z a t i o n s o f a l r e a d y e x i s t i n g o b s e r v a t i o n a l d a t a . Many b r a n c h e s of s c i e n c e have d e v e l o p e d f r o m t h e p r a c t i c a l e x p e r i e n c e and knowledge o f s u c h men as p r o s p e c t o r s , f a r m e r s and f i s h e r m e n . At f i r s t , e ach b r a n c h o f s c i e n c e was m e r e l y t h e c o m p i l a t i o n o f t h e a c c u m u l a t e d e x p e r i e n c e o f i n d i v i d u a l s , p a s s e d on from one g e n e r a t i o n t o t h e n e x t . I n t h i s f o r m , i t was no more t h a n a s e t o f f a c t s w h i c h p r o v i d e d l i t t l e b a s i s f o r p r e d i c t i o n . E v e n t u a l l y , a p o i n t was r e a c h e d where a n o m a l i e s and seeming c o n t r a d i c t i o n s began t o appear i n t h e o b s e r v a t i o n a l d a t a . These a n o m a l i e s were r e s o l v e d by t h e i n t r o d u c t i o n o f new t h e o r e t i c a l c o n s t r u c t s , termed "paradigms" by Kuhn. The appearance of such p a r a d i g m s , 2 i n t e g r a t i n g and explaining previously puzzling data, allowed science to progress u n t i l a point was reached where a new paradigm became necessary. As a c l a s s i c a l example of t h i s process, Kuhn ( 1 9 7 0 ) c i t e s the discarding of the Ptolemaic b e l i e f that the Earth i s the centre of the s o l a r system i n favour of the Copernican viewpoint. This opened the way f o r G a l i l e o , Kepler and Newton, whose theories held sway u n t i l they i n turn were perceived as only s p e c i a l cases of the more general theories of Albert E i n s t e i n . In the earth sciences, the point where a new paradigm became necessary was reached i n the l a t e 1950's, when the accumulation of oceanographic data presented s u r p r i s i n g r e s u l t s from the seabed. Mountain ranges of unprecedented length, and trenches of i n c r e d i b l e depth headed a l i s t of topographic features v a s t l y d i f f e r e n t from anything seen on the continental surfaces. These structures demanded an explanation, and were the d i r e c t cause of the emergence of plate tectonic theory. This r e v o l u t i o n i n thought, quite unlike anything which had taken place before i n the earth sciences, had the e f f e c t of taking the study of such apparently disparate phenomena as deep sea trenches and mountain b u i l d i n g and u n i t i n g them into a sing l e coherent theory. I t would appear to be e s s e n t i a l then, that any treatment of the earth sciences i n a secondary school be centred around t h i s theory. From a s o c i e t a l viewpoint, recent events i n world h i s t o r y . p o i n t to a need f o r students to understand the p o t e n t i a l and the l i m i t a t i o n s of the planet on which they 3 l i v e . P h r a s e s such as " o i l s h o r t a g e " , '"non-renewable r e s o u r c e " and " s o l a r power" are commonplace, and i n d i c a t e t h e t y p e of w o r l d the s t u d e n t w i l l occupy as an a d u l t . I t seems u n t h i n k a b l e t h a t j u s t as mankind i s s t a r t i n g t o r e a l i z e t h e t r u e i m p o r t a n c e of t h e e a r t h s c i e n c e s t o t h e c o n t i n u e d w e l f a r e of our r a c e , an e d u c a t i o n a l system s h o u l d e x i s t w h i c h does not p r o v i d e an o p p o r t u n i t y f o r j u n i o r h i g h s c h o o l s t u d e n t s t o i n v e s t i g a t e t h e i r p l a n e t . U n f o r t u n a t e l y , t h i s i s a p p a r e n t l y the case i n B r i t i s h C o l u m b i a . The r e a s o n s f o r t h i s l a c k a re many and d i v e r s e . W i l l i a m s ( 1 9 7 3 ) p o i n t s out a.number, i n c l u d i n g d e f i c i e n t t e a c h e r t r a i n i n g i n the e a r t h s c i e n c e s , l a c k of i n s t r u c t i o n a l t i m e due t o s c h o o l t i m e t a b l e c o n s t r a i n t s , and t e a c h e r b i a s t o w a r d s f i e l d s p e r c e i v e d as b e i n g "more i m p o r t a n t " t h a n e a r t h s c i e n c e . P r o b a b l y one of the c h i e f f a c t o r s w o r k i n g a g a i n s t adequate i n s t r u c t i o n i n e a r t h s c i e n c e i s t h e l a c k o f u p . t o da t e I n f o r m a t i o n , b o t h f a c t u a l and . t h e o r e t i c a l , i n t h e books p r e s c r i b e d as t e x t s f o r j u n i o r h i g h s c h o o l s c i e n c e by t h e B r i t i s h C o l u m b i a M i n i s t r y of E d u c a t i o n . A b r i e f p e r u s a l o f t h e s e , (Schmid, Murphy, 1 9 7 7 ; Schraid, 1 9 7 0 ; A n a s t a s i o u , 1 9 6 8 ; Woodrow, 1 9 7 0 ) shows t h a t v i r t u a l l y no m e n t i o n ' i s made of p l a t e t e c t o n i c s . F u r t h e r m o r e , r e f e r e n c e s t o examples and c o n d i t i o n s f o u n d i n B r i t i s h C o l u m b i a , t h e s t u d e n t ' s home t e r r i t o r y , are few and f a r between. F o r many student's,. t h e j u n i o r h i g h y e a r s r e p r e s e n t t h e i r l a s t f o r m a l c o n t a c t w i t h s c i e n c e . A l a r g e number o f s t u d e n t s , f o r r e a s o n s r a n g i n g f r o m • i n a b i l i t y t o d i s i n t e r e s t , e x e r c i s e t h e i r o p t i o n t o not e n r o l i n a s c i e n c e c o u r s e i n grade '11 o r 1 2 . Of t h e s t u d e n t s who do choose t o c o n t i n u e i n s c i e n c e , the m a j o r i t y e n r o l i n c h e m i s t r y , p h y s i c s o r b i o l o g y r a t h e r t h a n i n e a r t h s c i e n c e . I t f o l l o w s t h e n , t h a t i n o r d e r t o p r o p e r l y c a r r y out t h e r e q u i r e m e n t s o f a g e n e r a l e d u c a t i o n , j u n i o r h i g h s c h o o l s c i e n c e s h o u l d i n c l u d e as p a r t of i t s mandate as a s u r v e y c o u r s e , a s u b s t a n t i a l p o r t i o n of e a r t h s c i e n c e . T h i s need was o r i g i n a l l y r e c o g n i z e d i n 1 9 6 7 - 6 8 when th e j u n i o r h i g h s c h o o l s c i e n c e r e v s i o n committee o p e r a t i v e a t t h a t t i m e s e t out the p r e s e n t c o u r s e of s t u d i e s , r e s u l t i n g i n t he c u r r e n t l a b o r a t o r y manuals and r e a d e r s . I n 1 9 7 8 , a f t e r r e p r e s e n t a t i o n s made t o t h e B r i t i s h C o l u m b i a M i n i s t r y o f E d u c a t i o n by t h e p r e s e n t a u t h o r , on b e h a l f o f t h e B.C. S c i e n c e Teachers* A s s o c i a t i o n , t h e M i n i s t r y o f f i c i a l s r e c o g n i z e d t h a t t h e c u r r e n t c o u r s e o f s t u d i e s was i n need o f r e v i e w . T h e i r d e c i s i o n was n o t t o r e v i s e t h e c o u r s e c o m p l e t e l y , b u t t o b r i n g i t up t o d a t e by m e t r i c a t i o n , and i n c l u s i o n o f t h e r e s u l t s o f r e c e n t s c i e n t i f i c r e s e a r c h . The d e c i s i o n was a l s o made t o make t h e s t u d i e s more r e l e v a n t t o t h e s t u d e n t s ' l i v e s by i n c l u d i n g a g r e a t many more examples of s i t u a t i o n s p e c u l i a r t o B r i t i s h C o l u m b i a . To h e l p a c c o m p l i s h t h i s end, t h e p r e s e n t a u t h o r was engaged by P r e n t i c e - H a l l of Canada L t d . , p u b l i s h e r s of th e p r e s c r i b e d t e x t s , t o w r i t e and t e s t i n t h e c l a s s r o o m an e a r t h s c i e n c e s e c t i o n f o r a r e v i s e d e d i t i o n o f E x t e n d i n g S c i e n c e C o n c e p t s i n t h e L a b o r a t o r y ( S c h m i d , 1 9 7 0 ) . T h i s appointment was based upon t h e a u t h o r ' s e x p e r i e n c e as a c u r r e n t l y p r a c t i s i n g j u n i o r h i g h s c h o o l s c i e n c e 5 teacher, his knowledge of B r i t i s h Columbia gained through extensive t r a v e l and study, and his broad c o l l e c t i o n of samples and photographs b u i l t up over many years. METHODS Ph i l o s p h i c a l Basis The p h i l o s p h i c a l basis f o r t h i s curriculum i s the conviction that students learn by doing. In junior high school, the students w i l l normally be from twelve to sixteen years o l d . According to Piaget ( F l a v e l l 1963; De Cecco 1968), t h i s range of ages represents a t r a n s i t i o n a l phase when children's learning patterns are changing from the concrete operational stage to the formal operational stage. Some students i n the course w i l l s t i l l be i n the concrete operational stage, where concepts must be seen as concrete r e a l i t i e s i n order to be learned. Others w i l l have already progressed to the formal operational stage, where concepts may be learned as abstractions without the necessity f o r concrete r e a l i t y . To f a c i l i t a t e learning by both groups, most exercises are designed as laboratory i n v e s t i g a t i o n s where the student makes d i r e c t observations during concrete experimental procedures. Formal operations are introduced by questions i n which the student i s expected to generalize from the observations. The type of i n v e s t i g a t i o n used i s the so - c a l l e d "guided discovery method". In most laboratory i n v e s t i g a t i o n s , the student i s given e x p l i c i t i n s t r u c t i o n s regarding the use of equipment. Questions to be answered during the course of the experiment d i r e c t the processes of observing and 6 recording. The answers to these questions provide the f a c t u a l content of the exercise. In t h i s way, a reasonable balance i s maintained between content and process. Those parts of the course which can not be conveniently investagated i n a school laboratory s e t t i n g are described i n short expository narratives, supplemented by questions r e q u i r i n g both objective knowledge and the s k i l l s of analysis and synthesis. Course Objectives While following t h i s course of study, i t i s hoped that the students w i l l develop p a r t i c u l a r s k i l l s and a t t i t u d e s , and acquire c e r t a i n pieces of f a c t u a l knowledge. Although they are quite comprehensive, the following l i s t s of objectives make no pretense of being complete. a) Development of S k i l l s i ) process s k i l l s : - i d e n t i f y i n g problems - observing - recording and organizing dara - i n t e r p r e t i n g data - formulating hypotheses - p r e d i c t i n g - seeking f u r t h e r evidence i i ) communication s k i l l s : students w i l l be required to communicate* both o r a l l y and i n w r i t i n g as they record information, express ideas and l i s t e n to others. They w i l l also be required to read, both to progress through each exercise and to acquire a n c i l l a r y information. 7 i i i ) motor s k i l l s : while working on the laboratory i n v e s t i g a t i o n s , students w i l l l earn how to handle apparatus, to use measuring instruments, and to follow safe laboratory procedures. b) Development of Attitudes As well as learning the aforementioned e a s i l y definable s k i l l s , i t i s hoped that the students w i l l also learn the following a t t i t u d e s : - increased c u r i o s i t y about the natural world - r e s p o n s i b i l i t y f o r the state of t h e i r environment - co-operation with others i n a j o i n t venture - independence i n learning c) A c q u i s i t i o n of Factual Knowledge As well as process s k i l l s and a t t i t u d e s , students would normally be expected to gain some f a c t u a l knowledge from each exercise. This material, which i s f a r too great to be described here, i s stated i n ~hethe Objectives f o r each i n d i v i d u a l exercise. 8 PROPOSED CURRICULUM  General Outline of the Curriculum The course of study presented i n t h i s proposed curriculum would normally take about eighty hours of classroom work, probably spread over two school years. I f t h i s were f i t t e d i n t o the present junior science curriculum s p e c i f i e d by the B r i t i s h Columbia Ministry of Education, these two years would normally be Grade 8 and Grade 10. Accordingly, the sequence of the propsed curriculum has been ordered to present f i r s t those topics more e a s i l y understood by the younger students, followed by the more d i f f i c u l t t h e o r e t i c a l m a t e r i a l . Part 1 covers the erosional and depositional aspects of geology, concentrating upon the modification of the landscape by water and i c e , phenomena common i n B r i t i s h Columbia. P a r t i c u l a r examples are taken where possible from the Port Moody area, twenty kilometres east of Vancouver, where many of these processes may be observed i n microcosm. Part 2 introduces the i n t e r n a l structure of the Earth, i n c l u d i n g volcanism and earthquakes, culminating i n a study of plate t e c t o n i c s . Emphasis i s placed upon plate movement i n the v i c i n i t y of B r i t i s h Columbia, and the r e s u l t i n g e f f e c t s upon our province. Both Part 1 and Part 2 include sections on earth materials and earth h i s t o r y , introduced i n Part 1, and reviewed and extended i n Part 2. Throughout the course, reference i s c o n t i n u a l l y made to previously learned material. 9 Selected Areas of the Curriculum As described above i n the General Outline, the proposed curriculum i s divided into a number of topic areas. From each of these, selected student exercises have been excerpted f o r d e s c r i p t i o n and anal y s i s . The remaining portions of the proposed curriculum, i n c l u d i n g the Teachers' Manual, may be found i n the Addendum to t h i s volume. Part 1 The main topic areas covered i n Part 1 are those considered to be most e a s i l y understood by students i n grade 8. In the order covered, these are: Rocks, Mapping, Weathering and Erosion, Ancient L i f e , and G l a c i a t i o n . The section concludes with an example of a f i e l d t r i p s uitable f o r grade 8 students, i n which.a number of the processes described previously may be observed i n action. Rocks From a student's viewpoint, the main substance of our planet i s rock. While a geologist may argue i n favour of minerals, a student t r a v e l l i n g through B r i t i s h Columbia would very seldom come i n contact with an i s o l a t e d mineral i n a single mass large enough to be recognizable. For t h i s reason, rocks rather than minerals have been chosen f o r the i n i t i a l area of study of the materials of the Earth. In a l l of the junior high school texts consulted (e.g. Mathews, 1978; Jackson & Evans, 1973; Ramsey et a l , 1978), rocks are presented to the student i n a s t r i c t l y 10 d e s c r i p t i v e f o r m . T h e s t u d e n t i s e x p e c t e d t o r e a d a l e n g t h y n a r r a t i v e c o v e r i n g t h e f o r m a t i o n , c l a s s i f i c a t i o n a n d d e s c r i p t i o n o f r o c k s . I f a l a b o r a t o r y e x e r c i s e e x i s t s , i t i s c o n f i n e d t o t h e i d e n t i f i c a t i o n o f s p e c i f i c v a r i e t i e s o f r o c k . I n t h i s p r o p o s e d c u r r i c u l u m , a u n i q u e a p p r o a c h i s t a k e n t o t h e t o p i c o f r o c k s . T h e s t u d e n t i s c o n f r o n t e d i m m e d i a t e l y w i t h a n u m b e r o f s p e c i m e n s w h i c h h e i s e x p e c t e d t o d e s c r i b e , b u t n o t t o i d e n t i f y ( I n v e s t i g a t i o n 1, b e l o w ) . S i n c e m o s t s t u d e n t s h a v e h a d v e r y l i t t l e p r a c t i s e i n t h e . a r t o f w r i t i n g p h y s i c a l d e s c r i p t i o n s , a i d i s g i v e n i n t h e f o r m o f a d a t a t a b l e w i t h p r e - s e l e c t e d h e a d i n g s s u c h a s c o l o u r , t e x t u r e , p o r o s i t y e t c . I n t h i s w a y , t h e s t u d e n t l e a r n s t o d i r e c t h i s p o w e r s o f o b s e r v a t i o n a l o n g t h e m o s t p r o f i t a b l e p a t h s . F o l l o w i n g t h e d e s c r i p t i o n , s t u d e n t s a r e e x p e c t e d t o o r g a n i z e t h e i r d e s c r i p t i o n s s o t h a t t h e r o c k s a r e c l a s s i f i e d i n t o g r o u p s , ( I n v e s t i g a t i o n 2, b e l o w ) , , t h e r e b y i n t r o d u c i n g t h e p r o c e s s o f s i m p l i f i c a t i o n o f . d a t a b y c l a s s i f i c a t i o n . N o d i r e c t i o n i s g i v e n a s t o t h e t y p e o f g r o u p i n g e x p e c t i e d , s o f r o m a c l a s s o f t h i r t y o r m o r e s t u d e n t s , m a n y d i f f e r e n t c l a s s i f i c a t i o n s y s t e m s n a t u r a l l y e m e r g e . A c o m p a r i s o n o f t h e s t u d e n t s ' c l a s s i f i c a t i o n s y s t e m s ( f o r d e t a i l s , r e f e r t o t h e T e a c h e r s ' M a n u a l i n t h e A d d e n d u m ) , p o i n t s o u t t h e n e e d f o r c o n s i s t e n c y a m o n g s y s t e m s . F o l l o w i n g t h i s , t h e w e l l w o r n p a t h s o f d e s c r i p t i o n a n d i d e n t i f i c a t i o n a r e f o l l o w e d ( N a r r a t i v e 3 , I n v e s t i g a t i o n s 4- a n d 5 b e l o w ) . S i n c e t h e p r o p o s e d c u r r i c u l u m i s i n t e n d e d t o h a v e a s t r o n g 1 1 B r i t i s h Columbia regional bias, the rocks selected are those most commonly found i n t h i s province,, with a few others added to round out the groups. In t h i s way, a student i s equipped with the knowledge necessary to i d e n t i f y rocks he may f i n d during l o c a l t r a v e l . The same approach i s useful to a teacher who may prefer to c o l l e c t rather than purchase specimens. The following pages contain the student exercises on rock i d e n t i f i c a t i o n r e f e r r e d to above. 1 2 INTRODUCTION You l i v e on a giant space ship. It i s shaped l i k e a huge b a l l 1 2 7 0 0 km across, and has a mass of more than 1 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 tonnes! Each year i t c a r r i e s you a distance of nearly 9 5 0 m i l l i o n km through space. I t provides you with food, water, c l o t h i n g and sh e l t e r . During the day i t protects you from harmful r a d i a t i o n given o f f by the Sun. At night, i t prevents you from being i n s t a n t l y frozen. This space ship i s c a l l e d Earth, our planet, and i t i s a very unusual place. During your courses i n Earth Science, you w i l l explore the planet as i t i s today, and the way i t used to be i n the past. You w i l l study some of the materials of which i t . i s made, and how these came to be formed. You w i l l ,learn that over three b i l l i o n years ago the f i r s t l i v i n g being formed, and that through the centuries i t s descendents m u l t i p l i e d , changed, and spread. Today, there are over a m i l l i o n d i f f e r e n t types of l i v i n g beings, everywhere from the poles to the equator. In Earth science you w i l l study some of the animals and plants which l i v e d i n the past, and see how they may have gradually changed into the l i f e forms we recognize today. Although our planet feeds, clothes and protects us, i t can also be a very dangerous place to l i v e . In 1 9 0 2 Mt. Pelee, a volcano"on the i s l a n d of Martinique i n the Caribbean Sea, k i l l e d nearly 30 0 0 0 people i n the nearby town of St. P i e r r e . In 1 9 7 & an earthquake i n T'ang-shan, China, k i l l e d more than 650 000. I f people knew more about the Earth, these 13 d i s a s t e r s might have been a v o i d e d . I n E a r t h S c i e n c e , you w i l l l e a r n about t h e causes and e f f e c t s of t h e s e and o t h e r sudden changes i n our p l a n e t ' s s u r f a c e . I n B r i t i s h C o l u m b i a , d i s a s t e r s l i k e t h o s e i n S t . P i e r r e o r T'ang-shan have n o t happened i n our l i f e t i m e s . The s u r f a c e of our p a r t o f the p l a n e t i s s t i l l b e i n g changed however, b u t much more s l o w l y . E v e r y y e a r t h e r a i n and snow f a l l , w a t e r f r e e z e s i n t o i c e and m e l t s a g a i n , g r a d u a l l y w e a r i n g down and b r e a k i n g a p a r t t h e r o c k s w h i c h make up our m o u n t a i n s . E v e r y y e a r , m i l l i o n s o f t o n n e s o f t i n y p i e c e s of worn down r o c k , sand and mud are c a r r i e d t o t h e sea by. r i v e r s l i k e t h e F r a s e r . S l o w l y b u t s u r e l y , o ur l a n d i s b e i n g worn down and washed out t o s e a . The p r o c e s s i s u s u a l l y t o o slow t o n o t i c e , b u t i t i s j u s t as e f f e c t i v e as g i a n t e a r t h q u a k e s and l a n d s l i d e s . Even i f a mountain i s t h r e e k i l o m e t r e s h i g h , and i s worn down a t o n l y one c e n t i m e t r e e v e r y hundred y e a r s , i t w i l l be c o m p l e t e l y gone i n o n l y t h i r t y m i l l i o n y e a r s . Our p l a n e t has been h e r e f o r more t h a n 4600 m i l l i o n y e a r s . Why has our p r o v i n c e n o t been worn a b s o l u t e l y f l a t by now? The answer b e g i n s deep w i t h i n o ur p l a n e t . T h ere, where no p e r s o n has e v e r been, we t h i n k t h a t t h e r e a r e immensely t h i c k l a y e r s o f r o c k and i r o n ( F i g u r e 1 a ) . I t I s so h o t down t h e r e t h a t even s o l i d r o c k c a n bend and f l o w v e r y s l o w l y , .just as a s p h a l t f rom a r o a d c a n be made t o bend and f l o w on a h o t day i n summer. Over m i l l i o n s o f y e a r s , t h e s e s l o w l y f l o w i n g r o c k s have formed g i a n t c u r r e n t s w i t h i n .the. E a r t h , as t h e y r i s e , move a c r o s s t h e s u r f a c e , 14 Figure 1a. The layers of the Earth. The lithosphere i s the s o l i d crust; the asthenosphere i s the layer of slowly moving rock beneath the crust; the lower mantle i s a l a y e r of s o l i d rock between the asthenosphere and the l i q u i d i r o n of the outer core, and the s o l i d i r o n of the inner core. 15 F i g u r e 1 b . S l o w l y moving c u r r e n t s of r o c k i n the asthenosphere keep l a r g e areas" of the c r u s t , i n c l u d i n g the c o n t i n e n t s , moving from one p l a c e t o another on our p l a n e t . 16 65 m i l l i o n years ago 50 m i l l i o n years from now Figure 1c. During the past 200 m i l l i o n years, the map of the Earth has changed d r a s t i c a l l y as the continents have broken apart and moved to d i f f e r e n t p o s i t i o n s on the globe. 17 and sink again (Figure 1b). These currents are so huge that they can move entire continents, sometimes even break continents apart! Throughout the b i l l i o n s of years, the continents have been c a r r i e d l i k e giant r a f t s , f l o a t i n g on these currents of slowly moving rock. Sometimes the continents c o l l i d e and crumple, pushing up ranges of mountains s i m i l a r to those i n our province. Other times they s p l i t and. move apart (Figure 1c), creating small seas l i k e the Red Sea, or huge ocean basins l i k e the A t l a n t i c . Every year the currents move the continents a few centimetres. In your l i f e t i m e they may move one or , two metres. In a b i l l i o n years they could t r a v e l twenty-five times around the planet! Our world i s constantly changing. The forces of wind and weather slowly grind i t s surface down. The currents of rock deep within the planet b u i l d i t up again. In your courses i n Earth Science you w i l l learn about these processes, and-how they a f f e c t a l l of our l i v e s . 18 THE WORLD OF ROCK What are mountains made of? I f you d i g down through the layers of s o i l under a farmer's f i e l d , what w i l l you come to? I f you were to dive into the depths of the ocean, and continue on down through the mud on the bottom, what would you eventually reach? A l l three of these questions may be answered with the same word, ROCK. The entire surface of our planet, whether mountain, desert, or ocean f l o o r i s made of rock. You probably know already that not a l l rocks are the same. You may even know the names of some types of rock: granite, sandstone, or marble f o r example. Did you know that there are over f i v e hundred named kinds of rock? In t h i s section you w i l l study a few of these, and learn how to name and i d e n t i f y them. INVESTIGATION 1 Describing Rocks Purpose: to examine and describe a number of d i f f e r e n t rocks. Procedure A. Make up a data table with the following headings: Sample Number Colour Rough-ness Shape Hardness Holes Consistency Layers C r y s t a l s Other Things B. L i s t the sample numbers i n the f i r s t column of your data ta b l e . 1 9 C. Examine each rock sample and write i t s c h a r a c t e r i s t i c s i n your data t a b l e . These are some of the things you should look f o r : Colour: i s i t the same colour a l l over, or made up of d i f f e r e n t l y coloured pieces? What are the colours? Roughness: rough or smooth? Shape: are the edges rounded or sharp? Hardness: hard, or soft and crumbly? Holes: s o l i d , containing a few holes, or many holes? Consistency: does i t seem to be made of one single s o l i d piece of material, or does i t seem to be made of many d i f f e r e n t pieces a l l stuck together? Layers: i s i t made of layers or not? I f so, how thick are they? Are they smooth or wrinkled? C r y s t a l s : i s i t made up of cr y s t a l s ? I f so, how large are they? Are they d i f f e r e n t colours? Other Things: anything else you may notice about the rock which you think i s i n t e r e s t i n g . Questions 1 . Can two people always agree on what to c a l l the colour of a rock? 2 . How could two people who can not agree on what to c a l l the colour of a rock solve t h e i r problem? Conclusion What did you lea r n to do i n t h i s Investigation? 20 INVESTIGATION 2 Grouping Rocks I t i s nearly impossible f o r one person to learn about a l l the d i f f e r e n t types of rock. To s i m p l i f y t h i s , rocks may be c l a s s i f i e d into f a m i l i e s , or groups of s i m i l a r types of rock. For example, a l l the black, rocks may be placed i n one group, and a l l the red rocks i n another. Perhaps a l l the so f t rocks might go i n one group, and the hard ones i n another. Purpose: to c l a s s i f y rocks Into groups. Procedure A. Make up a data table l i k e t h i s : Group Name or Description Sample Numbers.of Rocks i n Each Group B. Use your descriptions from Inve s t i g a t i o n 1 to help you c l a s s i f y the samples into groups. Try to have not more than s i x d i f f e r e n t groups. When you have f i n i s h e d , compare your groups with those made by other students. Questions 1. Did a l l students make up the same groups, or were some oJ them d i f f e r e n t ? 2. Did some of your samples f i t i n t o more than one group? 3 . Did you have d i f f i c u l t y p l a c i n g some of your samples i n a group? 4-. What d i f f i c u l t i e s would geologists have i f each one used a d i f f e r e n t method of grouping.rocks? How could geologists solve t h i s problem? Conclusion . What d i d you lear n to do i n t h i s Investigation? 21 NARRATIVE $ A System l o r Grouping Rocks In Investigation 2 you learned about some of the d i f f i c u l t i e s which could arise i f each geologist used h i s own.system f o r c l a s s i f y i n g rocks. To avoid these problems, geologists around the world have a l l agreed to use the same system. I t i s not based upon the appearance of the rock, but upon how the rock was o r i g i n a l l y made. In t h i s n a r rative you w i l l learn about t h i s system, and the names that geologists use f o r t h e i r groups. The f i r s t group i s c a l l e d SEDIMENTARY-. Sedimentary rock i s formed from layers of SEDIMENT. Sediment consists of pieces of rock, usually quite small, such as pebbles, sand or s i l t . Sediment can be moved around, or c a r r i e d by wind or water. If the sediment i s c a r r i e d by water, i t may s e t t l e to the bottom of a sea or lake. I f i t has been c a r r i e d by the wind, i t may form a sand dune. Over many years, ground water may deposit material between the grains of sediment which w i l l cement them together. This, combined with the pressure from above may harden the sediment into rock. Sedimentary rocks may be recognized by t h e i r l a y e r s . Some may s t i l l show signs of the o r i g i n a l pieces from which they were made, p a r t i c u l a r l y i f these were pebble-sized. I f the bodies of animals or the leaves of plants were trapped i n the sediment as i t s e t t l e d , t h e i r remains may appear as f o s s i l s . Figures 1 and 2 show sedimentary rocks. The second group i s c a l l e d IGNEOUS. Igneous rocks are formed when very hot molten rock cools to become a s o l i d Igneous rocks are divided i n t o two sub-groups. 22 PLUTONIC igneous rocks are those which cooled very slowly, deep underneath the surface of the Earth. Over many thousands of years, pressure from inside the Earth has pushed them to the surface, where the material covering them has been washed away. Plutonic rocks are usually very hard. They are formed of quite large (greater than 1 mm) c r y s t a l s . Figure 3 shows an example of an igneous plutonic rock. VOLCANIC igneous rocks are those which cooled r a p i d l y , near the surface of the Earth. They may be hard or s o f t . Some may be f u l l of bubbles. Like plutonic rocks, they are also made up of c r y s t a l s , but these c r y s t a l s are very small. Usually they may be seen only with the aid of a microscope. Sometimes the rocks cooled so r a p i d l y that no c r y s t a l s formed, and the rock resembles glass. A volcanic igneous ,rock may be seen i n Figure 4-. METAMORPHIC rocks are rocks which have been changed from t h e i r o r i g i n a l form. They began as sedimentary or igneous rocks which were buried deep under the surface of the Earth. There, heat and pressure has changed them. This heat and pressure may have changed the shape and composition of the c r y s t a l s i n igneous rock. I t may have destroyed the layers or f o s s i l s i n sedimentary rock. Under s p e c i a l conditions, bands may form i n metamorphic rock, but these are quite d i f f e r e n t from the layers i n sedimentary rock. Metamorphic rocks are the most d i f f i c u l t to recognize You can see some metamorphic rocks i n Figure 5-(Ref.: B.C. Dep't of Mines and Petroleum Resources, 1968). 23 F i g . 1 d . Sandstone i s a s e d i m e n t a r y r o c k formed when g r a i n s o f sand are squeezed and cemented t o g e t h e r . F i g . 2. Conglomerate i s a s e d i m e n t a r y r o c k formed when p e b b l e s a r e squeezed and cemented t o g e t h e r . 24 .4 * A " ^ t 5 7t T >4W*>-< • F i g . 3- Granite i s a plutonic rock formed when molten rock cools slowly deep underground The large i n t e r l o c k i n g c r y s t a l s are c l e a r l y v i s i b l e . F i g . 4. Basalt i s a volcanic rock which forms when molten rock cools r a p i d l y . The c r y s t a l s are d i f f i c u l t to see without a magnifier. 2 5 F i g . 5« Gneiss i s a metamorphic rock found i n B r i t i s h Columbia. The c r y s t a l s l i n e up into i r r e g u l a r "bands". F i g . 6. Layers of coal and shale on Ellesmere Island i n the Canadian a r c t i c . (Photograph courtesy of the Geological Survey of Canada). 26 Questions 1 . What clue t e l l s you that the rocks shown i n Figure 6 are sedimentary? 2. How are f o s s i l s formed i n sedimentary rock? 3 . Explain why i t i s u n l i k e l y that f o s s i l s would form i n igneous rock. INVESTIGATION 4- Classifying; Rocks In Investigation 2, you found that d i f f e r e n t people sometimes have d i f f e r e n t methods of grouping rock samples. To avoid t h i s problem, geologists have agreed to use the same system a l l the time. Purpose: to c l a s s i f y rocks by using the geologists* system. Procedure A. Make a data table l i k e t h i s : Sample Number Group B. L i s t the sample numbers i n the f i r s t column. Examine each sample and decide whether i t i s sedimentary, igneous p l u t o n i c  igneous volcanic, or metamorphic. Write the correct group name f o r each sample i n the second column. Questions 1 . What i s sediment? How can i t form i n t o rock? 2. How i s igneous rock formed? 3 . How i s metamorphic rock formed? 4-. Exp l a i n the difference between volcanic and plutonic rock. Conclusion What d i d you learn about, rocks i n t h i s Investigation? 27 NARRATIVE 5 A Svstem f o r Naming Rocks " • — • —'— — So f a r , you have examined a number of rocks and c l a s s i f i e d them into groups. Now you w i l l learn how to. recognize and name p a r t i c u l a r types of rock. Remember though, that the names you learn w i l l be only a few of the many d i f f e r e n t names that geologists use. SEDIMENTARY rocks are usually named according to the siz e and shape of the o r i g i n a l pieces of sediment. Sediment Rock Name Rounded pebbles Conglomerate Sharp, angular pebbles Breccia Sand Sandstone Mud, clay or s i l t Shale Crushed s h e l l s of sea animals Limestone Crushed plant material Coal Note: limestone may also be recognized by i t s f i z z i n g r e a c t i o n with d i l u t e hydrochloric a c i d . IGNEOUS PLUTONIC rocks are named according to the materials of which t h e i r c r y s t a l s are made. Since you have not studied these materials, you w i l l use c r y s t a l colour to i d e n t i f y these rocks. C r y s t a l Colour Rock Name Mostly l i g h t c r y s t a l s L ight and dark c r y s t a l s , about evenly mixed Mostly dark c r y s t a l s Granite Quartz D i o r i t e Gabbro 28 IGNEOUS VOLCANIC rocks also may be named according to t h e i r colour. Description Rock Name Light colour Rhyolite Medium colour Andesite Dark colour Basalt Volcanic glass Obsidian Lightweight, "frothy" material Pumice Coarse c r y s t a l s embedded i n much f i n e r material Porphyry METAMORPHIC rocks are named according to the o r i g i n a l sedimentary or igneous rock from which they are made. In t h i s course you w i l l study only four types which are common i n B r i t i s h Columbia. Quartzite i s formed from sandstone. I t may resemble sandstone, but i s much harder. The grains are crushed together much more t i g h t l y i n quartzite than i n sandstone. Slate i s formed from shale. I t has very f i n e grains l i k e shale. Slate i s much harder than shale. I t s p l i t s into f a i r l y smooth sheets, but these s p l i t s are not i n the same d i r e c t i o n as the layers i n the o r i g i n a l shale. Marble i s formed from limestone. I t us u a l l y has c r y s t a l s , and f i z z e s with d i l u t e hydrochloric a c i d . Gneiss may be formed from several d i f f e r e n t kinds of rock. I t has c r y s t a l s , and often shows bands. These bands are not the same as sedimentary l a y e r s . 29 (Hamilton et a l , 1974-; Zim, Shaffer, 1957; B.C. Dep't of Mines and Petroleum Resources, 1968). Questions 1. I d e n t i f y each of the rocks shown i n Figures 1 to 5 . 2. Define the word "rock". (DO NOT copy a d e f i n i t i o n out of a d i c t i o n a r y . Write your OWN d e f i n i t i o n ! ) . INVESTIGATION 6 Naming Rocks Purpose: to give s p e c i f i c names to each of the rocks studied i n Investigation 4. Procedure A. Make a data table l i k e t h i s : Sample Number Rock Name B. L i s t the sample numbers i n the f i r s t column of your data t a b l e . Examine each specimen and write i t s name beside i t s sample number. For the names, you may have to r e f e r to Narrative 5 « Questions 1. Which has l a r g e r c r y s t a l s , granite or r h y o l i t e ? 2. Which i s usually harder, s l a t e or shale? 3. In some countries, s l a t e i s used as a r o o f i n g material f o r houses. What property of s l a t e makes i t p a r t i c u l a r l y u s e f u l f o r t h i s purpose? 4. Which i s more l i k e l y to contain f o s s i l s , shale or andesite? 5 . Which two types of rock f i z z with d i l u t e hydrochloric acid? 6. Pumice and obsidian are both made of volcanic glass. 30 Explain the difference between them. 7. At one time, B r i t i s h Columbia indians used obsidian f o r making arrowheads and axes. What property of obsidian made i t p a r t i c u l a r l y useful f o r t h i s purpose? Conclusion What d i d you learn about rocks i n t h i s investigation? 3 1 Rocks and Minerals - an alt e r n a t i v e approach. The world beneath your feet i s made up of three things, minerals, rocks and s o i l . Minerals are the basic chemical substances which make up the other two. Rocks are mixtures of minerals. S o i l i s fin e pieces of broken down rock, together with plants, animals, and t h e i r remains. In t h i s section you w i l l study two of these, rocks and minerals. Part 1 Grouping rocks A. Compare the specimens of sand stone and granite. Use a magnifier to look more c l o s e l y . Examine the piece of f r e s h l y broken granite f i r s t . Is granite made up of the same material a l l the way through, or i s i t made up of several d i f f e r e n t materials? How many are there? Are the pieces i r r e g u l a r or rounded i n shape? What are t h e i r colours? Now examine the sandstone. Answer the same questions that you answered fo r granite. Re-read your answers above, and write a few short sentences describing the dif f e r e n c e s between granite and sandstone. You have j u s t examined two completely d i f f e r e n t types of rock.. Granite was formed deep within the Earth, perhaps 1 5 or 2 0 km underground, when molten rock cooled and became s o l i d . I t i s made of mineral c r y s t a l s . Each i n d i v i d u a l piece that you can see i s a c r y s t a l , a l l Interlocked together with the other c r y s t a l s . Sandstone was formed on the surface of the Earth. Grains of sand were washed around by water, perhaps on a beach or by a r i v e r . As the pieces rubbed against each other, 32 t h e i r sharp corners were broken o f f , and the. grains became rounded. When they f i n a l l y s e t t l e d into place, pressure from above combined with materials deposited between the grains by the water hardened the loose sand into s o l i d rock. Geologists c l a s s i f y rocks into three main groups. You have just examined samples from two of these. Rocks l i k e sandstone, formed when grains of material are crushed and cemented together are, c a l l e d sedimentary rocks. Rocks l i k e granite, formed when molten material cools and hardens are c a l l e d igneous rocks. Write these two terms and t h e i r d e f i n i t i o n s i n your notebook. B. Examine the specimens provided. Which are sedimentary and which are igneous? Give a reason f o r each of your choices. C. Examine the samples of granite and gneiss (pronounced " n i c e " ) . Each i s formed of c r y s t a l s . How are the c r y s t a l s i n gneiss arranged d i f f e r e n t l y to the c r y s t a l s i n granite? Gneiss i s an example of a metamorphic rock. Metamorphic rocks are those which have been changed from t h e i r o r i g i n a l form by heat, pressure, or chemical action. Write...this term and i t s meaning i n your notebook. Gneiss i s formed when heat and pressure cause new c r y s t a l s to.grow-in p a r a l l e l streaks or bands. This can only happen when the rocks are .buried deep underground. . ,r J-D. You have just learned about the three groups of rocks used by geologists: sedimentary, igneous, and metamorphic. In the next few parts of t h i s exercise, you w i l l l e a r n more about each group. 33 Part 2 Sedimentary rocks E. Remember that these are made of material deposited by-water (and occasionally wind), then hardened into rock by pressure and cement. Examine samples of shale, conglomerate and sandstone, and look at the grains which make up each rock. Which has the largest grains? which has the smallest? Which would have needed fast, flowing water to move i t s grains? Which could have had i t s grains moved by very slow flowing water? P. Copy the table below into your notebook: Rock Name Grain Size Place where grains were deposited Conglomerate Sandstone Shale Now write each of the following phrases i n i t s correct place i n the table: medium grains; very f a s t flowing water; very small grains (mud or c l a y ) ; large grains (pebbles or boulders); very slow water; medium speed water. G. Compare samples of conglomerate and b r e c c i a . How can we t e l l that the grains i n b r e c c i a were not r o l l e d around i n a stream or on a beach before they were deposited? Try to describe a place i n which b r e c c i a could be formed. H. Compare two samples of limestone - one with f o s s i l s and one without. Can you i d e n t i f y any of these f o s s i l s ? In what sort of. place d i d limestone form? Put a drop of d i l u t e hydrochloric acid on each sample. Describe what happens. 34-What .is an easy way to i d e n t i f y limestone? G. Examine a geologic map of your home area. Describe the l o c a t i o n of a place where sedimentary rocks might be found. What kinds of rock are there? Try' to describe what t h i s place might have looked l i k e at the time the grains making up the rocks were deposited. I f you l i v e near the Rocky Mountains you w i l l be able to f i n d many kinds of sedimentary rocks to look "at. Part 3 Igneous rocks H. Examine samples of gabbro and ba s a l t . Which has the la r g e r c r y s t a l s ? Gabbro, l i k e granite, was formed when molten rock cooled very slowly, deep underground. When rocks are made t h i s way, they form large c r y s t a l s and are c a l l e d plutonic igneous rocks. Basalt was formed when molten lava, perhaps from a volcano, cooled r a p i d l y near the surface of the Earth. When rocks are made t h i s way, they form small c r y s t a l s and are c a l l e d volcanic igneous rocks. I. Igneous rocks are named according to the type of minerals they contain. You w i l l look mainly at the colours of these minerals. Mineral Colour Mostly l i g h t Light & dark,; evenly mixed Mostly dark : Name of Plutonic Rock Granite Quartz d i o r i t e Gabbro Name of Volcanic Rock Rhyolite Andesite Basalt Examine a number of igneous rock samples. I d e n t i f y each using a name from the table above. . 35 J . Examine.a geologic map of your home area. Describe a place where igneous rocks may be located, and the types of rocks found there. Try to write an explanation of how they may have got there. If you l i v e near the Coast Mountains of B r i t i s h Columbia there should be many plutohic igneous rocks nearby. Central B.C. has many.volcanic igneous rocks. Part 4 Metamorphic rocks K. Metamorphic rocks are made when another rock i s changed from i t s o r i g i n a l form by heat, pressure, or chemical a c t i o n . Several changes may take place. Sometimes the o r i g i n a l minerals may simply grow la r g e r . At other times, new minerals may form i n the rock. A t h i r d possible change i s the development of f o l i a t i o n which allows the rock to s p l i t i n t o sheets or f l a k e s . A number of metamorphic rocks may be found i n B r i t i s h Columbia. Marble: limstone which has grown l a r g e r c r y s t a l s forms marble. I t w i l l have the same f i z z i n g r e a c t i o n with d i l u t e hydrochloric acid that limestone has. Quartzite: sandstone which has been bound together so t i g h t l y by quartz cement that the r e s u l t i n g rock i s extremely hard and tough. When the rock i s broken, i t breaks through both cement and grains, whereas sandstone breaks around the grains. Slate, s c h i s t and gneiss are a l l f o l i a t e d (able to s p l i t ) rocks. Examine a l a b e l l e d sample of each, and write a b r i e f d e s c r i p t i o n of i t s appearance. They are a l l formed when other rocks are buried deeply, heated and compressed. 36 L. Examine' a geologic map of your home area. Describe a l o c a t i o n where metamorphic rocks may be found, and say which rocks are there. Try to write an explanation of how they may have been formed. Part 5 The rock cycle . You have already learned that rock can be changed from one type to another. For example, the sedimentary rock shale may become deeply buried i n the Earth where i t i s heated and compressed to become the metamorphic rock sla t e or perhaps gneiss. If i t i s buried deeply enough, i t may melt completely, then cool again to become an igneous rock, quartz d i o r i t e . If over m i l l i o n s of years, the igneous i s pushed to the surface of the Earth, i t may form part of a mountain. Eventually the mountain may be worn down by the weather, and the broken.pieces of rock may become sand. The rock has gone through a complete cycle from sediment, to sedimentary rock, to metamorphic rock, to igneous rock, and back to sediment again. This change from one type of rock to another i s c a l l e d the rock cycle, and i t could take hundreds of m i l l i o n s of years. Figure 6b shows the rock cycle as a diagram. Each arrow represents a possible route that a rock could take. What could happen to a metamorphic rock to change i t d i r e c t l y to sediment? How could a sedimentary rock become an igneous rock, without becoming a metamorphic rock f i r s t ? M. Try making a large copy of, the rock .cycle on a piece of . cardboard. Glue samples of each type of rock and sediment 37 at i t s correct place i n the cycle. You may have to use small transparent containers f o r the sediment. . Part 6 The minerals i n rocks N.'Examine a few m i l l i l i t r e s of crushed granite. Try to separate the grains into three separate p i l e s of s i m i l a r grains. Each p i l e i s one of the d i f f e r e n t minerals which make up granite. The two l i g h t e r coloured minerals are quartz and feldspar. Try to l a b e l each p i l e from the following des c r i p t i o n s : The darker t h i r d mineral may be mica or amphibole. Mica w i l l be i n t h i n , f l a t f l a k e s . Amphibole w i l l be i n la r g e r s o l i d pieces. 0. Compare a piece of granite with a piece of quartz d i o r i t e . Which has more quartz? Which has more feldspar? Which has more dark minerals? These four types of mineral make up many of the igneous rocks i n B r i t i s h Columbia. P. Examine a piece of c a l c i t e . Describe i t s appearance. C a l c i t e i s the main mineral found i n limestone. Place a drop o f . d i l u t e hydrochloric a c i d on the c a l c i t e . Describe what happens. C a l c i t e i s also found i n many types of sandstone. Use a magnifier to examine a piece of sandstone containing c a l c i t e . Can you see the grains of sand? Which mineral do Quartz Feldspar . glassy transparent grey i r r e g u l a r shape i r r e g u l a r broken surface d u l l cloudy white, grey, red, pink, green rectangular shape f l a t broken surface 38 you think they are made of? Drop d i l u t e hydrochloric acid on the sandstone. What happens? Where do you suppose the c a l c i t e i s located i n the rock? The c a l c i t e was deposited i n the rock by water, and i s the cement which holds the grains of sand together. Conclusion What have you learned about rocks and minerals i n t h i s exercise? ROCK Figure 6b. The rock c y c l e . 39 Mapping One of the major objectives of t h i s proposed curriculum i s the f a m i l i a r i z a t i o n of the students with both t h e i r l o c a l area and t h e i r province. Obviously t h i s would best be accomplished by a series of f i e l d t r i p s , however most teachers would probably f i n d t h i s i m p r a c t i c a l . The next best method i s through a study of maps, and t h i s i s the approach taken here. Since the students have just completed several days work on the i d e n t i f i c a t i o n of rocks, t h i s section i s started with an exercise on geologic mapping. F i r s t , a c l a s s exercise simulating geologic mapping (Teachers' Manual, Addendum) Is completed, followed by an examination of a geologic map. While the exercise as written (In v e s t i g a t i o n 7i below) centres on the Port Moody area, the p r i n c i p l e s i t embodies are e a s i l y t r a n s f e r r a b l e to a map of any area. F i r s t the student i s asked to l a b e l a s e l e c t i o n of l o c a l landmarks on a blank outline map. This builds up f a m i l i a r i t y with l o c a t i o n s that he may have already v i s i t e d . Next, the student locates and colours areas of various types of bedrock, thereby learning about l o c a l conditions, and simultaneously reviewing h i s knowledge of rocks. 40 The remainder of the Mapping section of the proposed curriculum ( r e f e r to the Addendum) consists of exercises in v o l v i n g the use of symbols, scales, a l t i t u d e s , contour l i n e s and p r o f i l e drawing. A l l of these exercises use maps of the. Port Moody area, however the p r i n c i p l e s involved may be e a s i l y transferred to any National Topographic System map. The following pages contain the student exercise on geologic mapping referre d to above. 41 THE WORLD OF GEOLOGIC MAPPING Geologists i n Canada spend much of t h e i r time examining the rocks which make up t h i s country. By doing t h i s , they are able to locate valuable resources such as mineral deposits, o i l wells and natural gas f i e l d s . From t h e i r r e s u l t s , they draw maps so that other people may use t h e i r observations. Canada i s so large that i t has not yet been mapped completely, even though the Geological Survey has been working since 1842! In the next Investigation you w i l l use a section of a map prepared by the Geological Survey of Canada to determine what kinds of rock occur i n a small section of southwest B r i t i s h Columbia. INVESTIGATION 7 Making a Geologic Map Purpose: to make a geologic map of the Port Moody area. Procedure A. On the outline map of the Port Moody area, locate and l a b e l each of these landmarks. Use a sharp p e n c i l , and p r i n t neatly. Burrard I n l e t Admiralty Point Indian Arm Buntzen Lake Bedwell Bay Sasamat Lake Belcarra Bay Elsay Lake Deep Cove Goldie Lake Buntzen Bay Cypress Lake Berry Point Cosy Cove 42 F i g . 7. Geologic map of the Port Moody area. The colours and markings represent various kinds of rock. 44' LEGEND Granite Gabbro Granodiorite Quartz D i o r i t e D i o r i t e A l l u v i a l , marine & g l a c i a l deposits Sandstone, shale & conglomerate etc. Tuff, b r e c c i a , agglomerate, andesite, Hornblende-granulite, amphibolite, gneiss, e t c . Migmatite 45 Roche Point Twin Islands Burns Point Raccoon Island Brighton Beach Jug Island Turtle Head Seymour River Gopher Lake Theta Lake Clegg Lake Mount Seymour Ca p i t o l H i l l Burnaby Mountain Eagle Mountain Mount Elsay Buntzen Ridge (between Buntzen Lake and Indian Arm) B. Examine the geologic map c a r e f u l l y . Notice how the various colours and symbols show the types of rock i n each area. On the map you prepared i n Procedure A, draw the boundaries between each rock type. Colour the squares representing each rock type on the Legend, then use the same colours on your map. Questions 1. Why do you suppose that geologic maps use colours instead of just symbols to show the rock types? 2. Is i t possible f o r a geologist to examine the rock i n every part of an area? 3. What things could cover the rock, preventing a geologist from examining i t ? 4. Can a geologist be absolutely sure of the types of rock to be found i n an area? Conclusion What d i d you lear n about geologic mapping i n t h i s investigation? (Roddick, 1965) 46 Weathering and Er-osion . One of the major sections i n Part 1 of the proposed curriculum involves the gradational and depositional aspects of geology. Since these are processes e a s i l y observable by students, t h e i r causes and e f f e c t s are treated at some length. The section begins i n a f a i r l y standard way with a s e r i e s of narratives and laboratory i n v e s t i g a t i o n s i n v o l v i n g simulation of weathering processes (Investigation 14, Addendum), the water cycle (Investigation 14, Narrative 15> Addendum) and stream abrasion (Investigation 17, Addendum). Investigations 18 and 1 9 (below) introduce data not e a s i l y available to the average teacher, but of great importance to B r i t i s h Columbia. These f i g u r e s are the long term monthly averages of water and sediment transported by the.Fraser River, one of the major drainage systems of the province. To aid the student i n a s s i m i l a t i n g the meaning of these f i g u r e s , he i s asked to draw a p a i r of simple bar graphs, thereby transforming the f i g u r e s i n t o v i s u a l form. Once these exercises have been completed, the students have a better f e e l i n g f o r the amounts of material involved, and the changes i n flow caused by d i f f e r i n g c l i m a t i c conditions throughout the year. Investigation 23 (below) i s a regional study of the Fraser d e l t a , one of the major areas of sediment deposition i n B r i t i s h Columbia. Here, the student studies a map and a s a t e l l i t e photograph of the d e l t a , and uses these to discover which areas may be experiencing growth, and which may be s t a t i c or d e c l i n i n g . This i s followed by Narrative 24 4-7 (below), a b r i e f d e s c r i p t i o n of the P i t t Lake d e l t a , an unusual landform caused by rev e r s a l of water flow, whose existence i s unknown to most teachers. The remaining exercises i n t h i s section on gradational and depostional processes ( r e f e r to the Addendum) include a microscopic study of sandy sediments, and a rather dramatic account of the Frank S l i d e of 1 9 0 3 . The following pages include the student exercises oh erosion and deposition r e f e r r e d to above. INVESTIGATION 18 Sediment Flow Every l i t t l e stream running down a mountainside c a r r i e s a load of sediment. Some sediment comes from s o i l washed away from the stream banks. More sediment comes from the abrasion of rocks, formed i n the way that you studied i n Investigation 1 7 . As the small streams j o i n together to form l a r g e r streams and r i v e r s , t h e i r loads of sediment also j o i n . Large r i v e r s l i k e the Fraser or the Skeena carry huge amounts of sediment down to the sea each year. In t h i s i n v e s t i g a t i o n , you w i l l study how t h i s amount of sediment changes.over the course of a year. Purpose: to study the amount of suspended sediment c a r r i e d by the Fraser River during a year. 4 - 8 Procedure A. The Fraser River s t a r t s i n the Rocky Mountains just west of the town of Jasper. I t flows north, then turns south near Prince George. At the v i l l a g e of Hope, the r i v e r turns west, and flows through the Fraser Valley, past the c i t i e s of Mission and New Westminster to the sea. 2 The Fraser drains an area of approximately 2 3 0 0 0 0 km . Use your a t l a s to measure the approximate length of the Fraser i n kilometres. B. The table below shows the average sediment flow i n the Fraser, measured at Mission. The f i g u r e s are the d a i l y average f o r each month during the years 1 9 6 5 to 1 9 7 6 . Sediment Flow at Mission (tonnes per day) Jan. 3 7 2 0 J u l . 1 0 1 600 Feb. 1 760 Aug. 3 6 0 0 0 Mar. 5 7 3 0 Sep.. 16 0 0 0 Apr. 3 4 - 3 0 0 Oct. 1 1 4 - 0 0 May 188 0 0 0 Nov. 7 5 2 0 Jun. 2 3 0 0 0 0 Dec. 3 5 4 - 0 Use the above data to p l o t a bar graph showing the d a i l y sediment flow f o r each month. Use a suitable scale such as 1 cm = 1 0 0 0 0 t/day. (Inland Waters Directorate, 1 9 7 8 b ) Questions 1 . In which month does the Fraser carry the most sediment? Calculate the t o t a l amount of sediment c a r r i e d during t h i s month. 2 . Try to explain why the Fraser c a r r i e s more sediment i n June than i n February. 49 3. During the years shown, an average of approximately 2 0 0 0 0 0 0 0 tonnes of sediment are washed, past Mission each year. Try to imagine that t h i s sediment i s ca r r i e d , not by a r i v e r , but by t r a i n s . Imagine that each t r a i n has 1 0 0 cars., and each car c a r r i e s 1 0 0 tonnes. a) .How much sediment would each t r a i n carry? b) How many t r a i n s would be needed each year? c) How many t r a i n s would be needed each day? d) During June, the Fraser c a r r i e s 230 000 tonnes of sediment each day. About how many t r a i n s would be needed each hour to carry t h i s amount of sediment? Conclusion In t h i s i n v e s t i g a t i o n , what d i d you le a r n about the amount of sediment c a r r i e d by the Fraser River? INVESTIGATION 1 9 Water, flow The l a s t i n v e s t i g a t i o n showed you how the amount of sediment c a r r i e d by a r i v e r changes throughout the year. You probably suspected that the amount of sediment c a r r i e d depended upon the amount of water flowing i n the r i v e r . In t h i s i n v e s t i g a t i o n , you w i l l study the changes i n water flow i n the Fraser River throughout the year. Purpose: to study the amount of water c a r r i e d by the Fraser River thoughout the year. Procedure A. The table below shows the average d a i l y water flow i n the Fraser River f o r each month during the years 1 9 6 5 to 1 9 7 6 . Make a bar graph of the information. Use a suit a b l e 50 3 v e r t i c a l scale such as 2 cm = 1000 nr/s. Water Flow at Mission (cubic metres per second) Jan. 1560 . J u l . 7070 Feb. 1290 Aug. 4-590 Mar. 1320 Sep. 3060 Apr. 2150 Oct. 2550 May 5870 Nov. 2270 Jun. 8790 Dec. 164-0 (Inland Waters Directorate, 1978c) B. Compare t h i s graph with the one you drew i n Investigation 18. Do the high points occur i n the same month? Dp the low points occur i n the same month? Explain why t h i s s i m i l a r i t y occurs. Questions ' 1. During the month of June, an average of 8790 nr/s of water flow past Mission. How much water flows i n a) one minute? b) one hour? c) one day? d) the entire month (30 days)? 2. Explain why the greatest water flow occurs i n June, and the l e a s t i n February. (Hint: i t has something to do with the weather). Conclusion In t h i s i n v e s t i g a t i o n , what d i d you l e a r n about the amount of water c a r r i e d by the Fraser River? 51 INVESTIGATION 25 Deltas A l l r i v e r s carry sediment, some more than others. Eventually the r i v e r flows into a body of quiet water such as the sea or a large lake. Here the force of gravity overcomes the a b i l i t y of the water to keep the sediment a f l o a t , and so the sediment sinks to the bottom. These deposits of sediment at the mouth of a r i v e r form a d e l t a . Purpose: to study a number of d e l t a s . Procedure A. On an outline map of the Eraser Delta (Figure p r i n t the following l a b e l s . Obtain your information from a topographic map. Use a sharp p e n c i l , and p r i n t neatly. C i t i e s : Vancouver, Port Moody, New Westminster, White Rock. Waterways: Georgia S t r a i t , Burrard I n l e t , Indian Arm, Coquitlam Lake, Coquitlam Siver, P i t t Lake, P i t t River, E n g l i s h Bay, Boundary Bay, Mud Bay, • Fraser River, North Arm, Middle Arm, South Arm. Land Areas: Lulu Island, Sea Island, Westham Island, Annacis Island, Point Roberts. Delta Front Areas: Spanish Bank, Sturgeon Bank, Roberts Bank, Boundary Bay T i d a l F l a t s . B. Examine Figure fO, a s a t e l l i t e photograph of the Fraser Delta and Georgia S t r a i t . On.your map, shade i n l i g h t l y and l a b e l the area where sediment i s being swept into Georgia S t r a i t . Which of the d e l t a front areas named i n Procedure A are growing l a r g e r at present as sediment i s being swept on to them? Which areas do not appear to be growing at present? C. Figure 12 shows the d e l t a of the r i v e r N i l e i n Egypt. Explain why the d e l t a shows the dark colour of vegetation, while a l l around i s l i g h t coloured desert. D. Aklavik, a town b u i l t on the d e l t a of the Mackenzie River i n Canada's Northwest T e r r i t o r i e s i s shown i n Figure 1 3 . . Examine the photograph and t r y to suggest one of the hazards of l i v i n g on a d e l t a , and the reason why Aklavik has been l a r g e l y abandoned. E. Figure 14 i s a photograph of the Squamish River d e l t a , about 5 0 kilometres north of Vancouver. Two i n d u s t r i e s are located on t h i s d e l t a , a sawmill and a small chemical manufacturing plant. Why are deltas often chosen as. suitable s i t e s f o r i n d u s t r i a l areas? F. Set the stream table on an angle of 2 0 ° . With your f i n g e r , make a s t r a i g h t shallow, groove to guide the water. Start the water flow and wait f o r several minutes f o r a d e l t a to form. Does the water always follow the same path when depositing the sediment? Sketch a top view of the r e s u l t i n g d e l t a . Questions Fraser River Records . Maximum flow 1 5 1 7 7 ni 5/s May 3 1 , 1 9 4 - 8 Minimum flow 340 nrVs Jan. 8, 1 9 1 6 (Inland Waters Directorate, 1 9 7 8 c ) 1 . The amount of water c a r r i e d by a r i v e r can vary greatly from day to day and from month to month. Above are the record high and low flow rates f o r the Fraser River. The year 54 F i g . 10- A s a t e l l i t e p h o t o g r a p h of t h e F r a s e r d e l t a , G e o r g i a S t r a i t , and s o u t h e r n Vancouver I s l a n d . R i v e r ".-—•» • - - -Sea — - — coarse^vT s e d i m e n t ^ - — f i n e ^ - ^ " s e d i m e n t ^ F i g u r e 11. D e l t a f r o n t . 5 5 F i g . 12- The d e l t a of the r i v e r N i l e i n Egypt (NASA photograph). F i e 13. The town of Aklavik i s b u i l t on the d e l t a of th f MacKenzie River i n Canada's North West T e r r i t o r i e s . 56 F i g . 1 4 - . A chemical plant and a sawmill have been b u i l t on the Squamish River d e l t a . 57 194-8 produced the most disastrous floods ever known i n the Fraser V a l l e y . 1916 was a year of record low temperatures. a) Why does the greatest water flow u s u a l l y occur i n the l a t e spring or early summer? b) Why should the winter temperature a f f e c t the rate of water flow? 2 . Figure 15 shows a cross-section of a r i v e r i n two d i f f e r e n t seasons. During the spring floods, i t spreads across the p l a i n and deposits i t s load of sediment. During the r e s t of the year, i t i s confined to a c e n t r a l channel. a) Why i s a f l o o d p l a i n a good place f o r agriculture? b) What i s one of the hazards of l i v i n g on a f l o o d plain? c) How could floods be prevented? d) What w i l l be the eventual e f f e c t upon the f e r t i l i t y of the land i f floods are prevented? 3. Figure 16 i s a diagram of a d e l t a f r o n t . Copy t h i s diagram i n t o your notes. a) W i l l the heavy sediment be dropped close to the r i v e r , or f a r t h e r out to sea? b) W i l l the f i n e sediment l i k e s i l t be dropped close to the r i v e r , or f a r t h e r out to sea? c) Label on your diagram the places where conglomerate, sandstone and shale could p o s s i b l y be forming i n t h i s d e l t a . 4-. Why would a dam b u i l t across a muddy r i v e r l i k e the Fraser eventually become useless? Conclusion What i s a d e l t a , and why does i t form? 58 Normal flow Spring f l o o d Figure 1 5 - Flood p l a i n of a r i v e r . Figure 16. Outline of a d e l t a front, (Steepness greatly exaggerated). 59 NARRATIVE 24 1 The Mystery of P i t t Lake In Figure 17, you can see a map of the south end of P i t t Lake, a large body, of water 50 kilometres east of Vancouver. The water flows into P i t t Lake from the north, and flows out through the P i t t River, into the Fraser. Normally, deltas occur where a r i v e r flows into quiet water, and not where i t flows out of a lake. Yet here, a large d e l t a i s quite c l e a r l y being formed where the P i t t River- leaves the lake! How can t h i s happen? We must look to the sea and i t s t i d e s f o r an explanation. During very high t i d e s , sea water f l o o d i n g i n t o the mouth of the Fraser r a i s e s the water l e v e l i n the r i v e r . This i n turn pushes water from the Fraser i n t o the P i t t , causing the P i t t to flow backwards f o r a short while. During these periods of reverse flow, sediment i s washed back into P i t t Lake and deposited, forming t h i s most unusual d e l t a . (Roddick, 1965) Ancient L i f e Any study of earth science must include a study of earth h i s t o r y since the present Earth i s obviously a product of i t s own past. In the grade 8 s e c t i o n of t h i s proposed curriculum, earth h i s t o r y i s described i n terms of the plants and animals which l i v e d during the past, and i s investigated d i r e c t l y through the study of f o s s i l s . The topic is, introduced i n Narrative 27 (below) by a 60 61 unique comparison between the time d i v i s i o n s of the geologic column and the time d i v i s i o n s of our everyday calendar. In t h i s way, the student i s able to f i t unfamiliar terms such as eon and era into an already f a m i l i a r pattern. Narrative 27 continues with a very b r i e f d e s c r i p t i o n of the l i f e forms abundant during the Phanerozoic eon. This i s followed by Investigation 28 i n which the student organizes information found i n t h i s and other books into the form of a chart. The study of f o s s i l s , a topic which appears to have i n t r i n s i c i n t e r e s t . f o r junior science students, begins with Investigation 29 (below). E s s e n t i a l l y , t h i s i s a guessing exercise i n which students attempt to deal with a number of unfamiliar f o s s i l s . The looseness of t h i s i n v e s t i g a t i o n as i t i s written enables the teacher to t a i l o r i t to the s p e c i f i c needs and a b i l i t i e s of the c l a s s . Investigation 30 (below) continues the study of f o s s i l s by introducing s p e c i f i c specimens, and d i r e c t i n g observation towards p a r t i c u l a r points of i n t e r e s t . Emphasis i s placed upon specimens which might be found at locations i n B r i t i s h Columbia. The section concludes (see Addendum) with narratives and i n v e s t i g a t i o n s covering the topics of f o s s i l i z a t i o n and dinosaurs. The following pages contain the student exercises on earth h i s t o r y r e f e r r e d to above. 62 THE WORLD OF ANCIENT LIFE Most people have heard of f o s s i l s , the remains of plants and animals preseved f o r m i l l i o n s of years by being buried i n rock. Geologists are extremely inte r e s t e d i n f o s s i l s because they provide the only record of what kinds of l i v i n g beings inhabited the Earth i n ancient times. Before we begin our study of f o s s i l s however, we should learn the names that geologists use f o r various times i n the past. Just as we divide years into sections c a l l e d months, weeks and days, geologists have divided the en t i r e l i f e of the Earth into sections. These sections are c a l l e d eons, eras, and periods. NARRATIVE 27 The Geological "Calendar" Our Calendar Geological Calendar r— week rday - day - day •- day - day - day L day - p e r i o d r—Era - L period L p e r i o d r- Month week i - Eon Era week Era I— week L i f e of — Earth Year Month f— Month •-Eon 65 Although, the methods of d i v i d i n g up time are s i m i l a r , the lengths of the sections are quite d i f f e r e n t . Even the shortest- of.the geological time d i v i s i o n s are m i l l i o n s of years i n length. Just as our months and days have d i f f e r e n t names, the d i v i s i o n s of the geological calendar also have names. The Earth's h i s t o r y i s divided into only two eons, the Cryptozoic Eon and the Phaherozoic Eon. The word "cryptozoic" comes from two Greek words meaning "hidden l i f e " . This term was chosen because we know very l i t t l e about what kinds of plants or animals were a l i v e then. The word "phanerozoic" means " v i s i b l e l i f e " , and i t was chosen because we have a large number of f o s s i l s from t h i s eon. The Cryptozoic Eon covers about the f i r s t 9 / 1 0 of the Earth's h i s t o r y . During t h i s eon, the only l i f e present on Earth that we know about consisted of b a c t e r i a , s o f t -bodied animals, and simple p l a n t s . Most of these l e f t no f o s s i l record for. us to see. In Canada, a few f o s s i l b a c t e r i a preserved i n 2 b i l l i o n year old rocks near Thunder Bay, Ontario, represent some of the oldest l i v i n g things ever found. (Barghoorn, 1 9 7 1 ) The Phanerozoic Eon covers the remaining 1 / 1 0 of the Earth's l i f e t i m e , about 600 m i l l i o n years. This eon i s divided into three eras. These are c a l l e d the Paleozoic Era, meaning "ancient l i f e " , the Mesozoic Era meaning "middle l i f e " , and. the Cenozoic Era or "recent l i f e " . The Paleozoic Era could be c a l l e d the "age of invertebrates. Invertebrates are animals without backbones. 64 F i g . 18- F o s s i l t r i l o b i t e s . These a n i m a l s l i v e d on t h e bottom o f a s h a l l o w s e a many hundreds o f m i l l i o n s o f y e a r s ago. F i g . 1 9 . Lambeosaurus. T h i s d i n o s a u r s k e l e t o n i s on v i e w i n t h e Geology b u u l d i n g a t t h e U n i v e r s i t y of B r i t i s h C o l u m b i a . 6 5 This era began with the appearance of many small sea animals such as t r i l o b i t e s (Figure 18), brachlopods, (a type of s h e l l f i s h ) , and s n a i l s . The t r i l o b i t e s are believed to be the ancestors, of present day crabs and l o b s t e r s . Paleozoic f o s s i l s may be found i n the Rocky Mountains of eastern B r i t i s h Golumbia. The Mesozoic Era, known as the "age of r e p t i l e s " , was the time when the great dinosaurs roamed the Earth. Much of Alberta i s covered by sedimentary bedrock deposited during the Mesozoic Era. Within these rocks are found the f o s s i l skeletons of r e p t i l e s (Figure 19). In B r i t i s h Columbia, Mesozoic rocks are located on Vancouver Island, and i n the Peace River area. Re p t i l e skeletons have been found near the Peace River, but not on Vancouver Island. The Cenozoic Era, which includes the present day, has sometimes been c a l l e d the "age of mammals", f o r t h i s i s the time when a great v a r i e t y of mammals f i r s t appear i n the f o s s i l record. Cenozoic f o s s i l s formed during the l a s t 1 million-years may be found i n many parts of B r i t i s h Columbia, i n c l u d i n g Coquitlam. (Casanova, 1 9 5 7 ) . INVESTIGATION 28 Cenozoic, Mesozoic and Paleozoic Purpose: to le a r n about the three most recent eras of the Earth's h i s t o r y . Procedure A. Make a large copy of the following table In your notes, then f i l l I n the blanks. Obtain your information from a reference book such as Reading About Science 1 _ , Chapter 5 3 -66 Era Began ( m i l l i o n s of years ago) Ended ( m i l l i o n s of .years ago) Cenozoic Mesozoic Paleozoic Duration ( m i l l i o n s of years) Main Forms of L i f e INVESTIGATION 29 F o s s i l Study Purpose: to observe and t r y to i d e n t i f y a number of f o s s i l s . Procedure • . A. Copy t h i s table into your notebook. Specimen Number What i s i t ? Answers to Questions B. For each specimen, f i l l i n the t a b l e . Try to i d e n t i f y the f o s s i l i f possibl e . Answer any questions which appear with each specimen. 67 Conclusion What did you learn about f o s s i l s i n t h i s exercise? . INVESTIGATION ?0 F o s s i l I d e n t i f i c a t i o n Many people can recognize, a f o s s i l when they f i n d one, but very few can give the correct name of i t . In t h i s exercise you w i l l learn to i d e n t i f y a number of f o s s i l s . Purpose: to learn how to i d e n t i f y and draw a s e l e c t i o n of common f o s s i l s . Procedure Using the specimens provided, complete each of the following sections. A. T r i l o b i t e s ' a) What does the p r e f i x " t r i " suggest? Into how many parts can the t r i l o b i t e be divided?-b) Does the t r i l o b i t e more c l o s e l y resemble a lobst e r , clam or octopus? c) Sketch the specimen as neatly and accurately as possib l e . B. S o l i t a r y Corals a) Use a reference book to f i n d out whether a c o r a l i s an animal or a plant. Record your answer. b) Why i s the c o r a l l i t e smaller at one end? c) Look up the meanings of the words " s o l i t a r y " and "colony". What might be a major di f f e r e n c e between the ways that s o l i t a r y c orals and c o l o n i a l corals l i v e ? d) Draw a top view and a side view of your specimen. 68 C. Brachiopods These were common animals throughout most of the Paleozoic Era, but today there are only a few species l i v i n g . Some people confuse brachiopods with clams, but t h e i r external s h e l l s and t h e i r i n t e r n a l body structure i s quite d i f f e r e n t . a) How many pieces are there to a brachiopod she l l ? b) Sketch the brachiopod. D. Mollusks These are a group of soft bodied animals which often have s h e l l s f o r protection. There are numerous f o s s i l mollusks, and over 1 5 0 0 0 species l i v i n g today. There are three common groups of f o s s i l mollusks: a) Gastropods (the s n a i l group). These animals have a s h e l l which i s wound into a s e r i e s of c o i l s . Some species l i v e i n s a l t water, others i n f r e s h water, and s t i l l others on land. F o s s i l gastropods are common i n the Fraser V a l l e y . i ) How many parts does a gastropod s h e l l have? i i ) Sketch a gastropod s h e l l . b) Pelecypods (the clam and oyster group). These are often c a l l e d "bivalves" because they have.a two part hinged s h e l l . F o s s i l pelecypods are common i n B.C. (Wagner, 1 9 5 9 ) i ) Name another edible pelecypod besides the clam and the oyster. i i ) Sketch two d i f f e r e n t types of pelecypod. c) Cephalopods (the ammonite and squid group). Most present day cephalopods l i k e the octopus and squid do not have external s h e l l s . Many of .their f o s s i l r e l a t i v e s however 69 d i d have shells. The largest f o s s i l ammonite ever found i n Canada was located near the v i l l a g e of Fernie, i n southeast B r i t i s h Columbia. I t s s h e l l was about 1.5 metres i n diameter. (Frebold, 1964) i ) What is.the major difference i n shape between an ammonite s h e l l and a gastropod shell? i i ) Sketch the ammonite s h e l l . E. Crinoids Crinoids look more l i k e plants than animals. They are attached to the sea bottom by a f l e x i b l e stem, with the main body of the animal l i v i n g i n a cup-like s h e l l above. a) Sketch a section of c r i n o i d stem. F. Sharks. Sharks do not have a bony skeleton. Their skeleton i s made up of a material c a l l e d " c a r t i l a g e " , which i s s i m i l a r to very tough g r i s t l e . The parts of sharks most frequently f o s s i l i z e d are t h e i r teeth and hard f i n spines. a) What' are the main di f f e r e n c e s between the shape of a shark tooth and the shape of a human front tooth? b) Sketch the f o s s i l shark tooth. G. Rept i l e s The parts of r e p t i l e s most commonly preserved are t h e i r bones. P e t r i f i e d bone i s very hard, and u s u a l l y brownish i n colour. Occasionally, whole skeletons have been found i n Al b e r t a . Preserved dinosaur f o o t p r i n t s have been found along, the Peace River i n northeast B r i t i s h Columbia. (Swinton, 1965) a) Describe one way i n which your specimen resembles bone. 7 0 b) How can you t e l l that the bone has been p e t r i f i e d ? c) Sketch the bone specimen. H. Plants Plants are f o s s i l i z e d when leaves or stems are trapped i n layers of fine, sediment. Many f i n e specimens may be found near the town of Princeton i n southern B r i t i s h Columbia. (Rice, 1 9 6 0 ; Tidwell, 1 9 7 5 ) a) Why do you suppose that complete f o s s i l i z e d leaves are f a i r l y rare? b) Sketch the specimen leaves. . c) Use a reference book to f i n d out how coal i s formed. Summarize your fi n d i n g s i n a few short sentences. Questions 1 ' . . What i s a f o s s i l ? 2. Describe three d i f f e r e n t things that a study of f o s s i l s could t e l l us about the dis t a n t past. Conclusion What d i d you learn about f o s s i l s i n t h i s investigation? G l a c i a t i o n B r i t i s h Columbia i s a product of the i c e age. Less than 1 0 0 0 0 years ago, p r a c t i c a l l y a l l of our province was covered with g l a c i a l i c e . S i g n i f i c a n t portions of the Coast Mountains, the I n t e r i o r Ranges, and the Rocky Mountains are s t i l l covered by g l a c i e r s . Accordingly, i f a student i s to have an appreciation of the o r i g i n s of the p r o v i n c i a l landscape,, a study of g l a c i a t i o n and g l a c i a l landforms ? 1 i s e s s e n t i a l . Most earth science courses aimed at jun i o r science students (e.g. Mathews, 1978) devote comparitively l i t t l e space to g l a c i a t i o n , presumably as a r e s u l t of t h e i r United States authorship, that area being very l i t t l e a ffected by continental g l a c i a t i o n . Even those written by a Canadian author (e.g. Janes, 1974-) tend to concentrate on the depositional landscape of Ontario. The one text which does deal with alpine g l a c i a t i o n (Schmid, Murphy, 1977) tends to gloss over continental g l a c i a t i o n . This proposed curriculum deals with both the r e s u l t s of the i c e age, and with the causes and e f f e c t s of present g l a c i a t i o n . The section i s introduced by an i n v e s t i g a t i o n of the extent of continental g l a c i a t i o n (Investigation 35, below) and a comparison with present day g l a c i a t i o n . Students are asked a number of leading questions, designed to help them to "discover" the reasons f o r the present g l a c i e r s i n B r i t i s h Columbia. Investigation 56 (below) continues the study with the formation of g l a c i e r s , t h e i r structure, and the ways i n which they modify the landscape. The study i s completed i n Investigation 37 (below) i n which the student learns about how the g l a c i a l landforms frequently observed i n . B r i t i s h Columbia were produced. The- following pages contain the exercises on g l a c i a t i o n described above. 7 2 THE WORLD OF ICE Many people i n other parts of the world think of Canada as being a very cold country. In the wintertime, t h i s impression i s quite correct. Except f o r a narrow coastal s t r i p of B r i t i s h Columbia, Canada i s mostly covered with snow f o r four or f i v e months of the year. Fortunately, t h i s snow melts away during the summer, otherwise we would f i n d ourselves i n the grip of another i c e age. INVESTIGATION 55 The Ice Age Purpose: to study the ice age i n Canada. Procedure A. Examine the map of ice age Canada. On the f i r s t outline map (Figure 20), sketch l i g h t l y i n p e n c i l the edges of the area covered by i c e . Use a coloured p e n c i l to shade the ice-covered area very l i g h t l y i n blue. Label the edge of the ice-covered area neatly as the "Maximum extent of i c e , 18000 years ago". T i t l e t h i s map, "Canada During the Ice Age". B. The i c e did not form everywhere at once, but spread out from four centres. Label these neatly as follows: a) In the middle of Greenland, "Greenland Ice Sheet". b) East of Hudson Bay, "Labrador Ice Sheet". c) Northwest of Hudson Bay, "Keewatin Ice Sheet". d) Along the length of the Rocky Mountains, " C o r d i l l e r a n Ice". C. Fortunately, most of the ice has melted. The G l a c i a l Map of Canada shows i n dark blue those areas.of our country gure 20 . Outline maps of Canada f o r Investigation 35* 74 which are s t i l l covered by i c e . On your second outline map, shade these areas (approximately) i n blue. Although i t i s not part of Canada, shade Greenland with blue since i t i s . a l s o covered with i c e . T i t l e t h i s map, "Present Day Ice Sheets and G l a c i e r s " . D. As you might expect, most of.Greenland and some of Canada's a r c t i c islands are i c e covered. Make a l i s t of the other places i n Canada where many g l a c i e r s are found. Questions 1. Ice forms when snow i s compressed. (Remember what happens when you make a hard snowball). In nature, t h i s happens when so much snow f a l l s during a winter that the bottom layer s are squeezed into i c e by the weight of snow on top. Sometimes the i c e does not completely melt during the next summer. I f t h i s process continues f o r several years, a g l a c i e r w i l l s t a r t to grow. a) On the west coast of Canada, which ocean provides the water to make snow? b) Where do the cold winds necessary to freeze the water into snow come from? c) Look at your answers to (a) and (b), then t r y to explain why there are more g l a c i e r s i n the 0 o a s t Mountains than i n the Rocky Mountains. 2. S c i e n t i s t s exploring northern Canada have found evidence to show that plants, animals, and even men were l i v i n g there during the height of the i c e age (Guthrie, 1972). a) During the i c e age, which part of northern Canada was not covered with ice? 75 b) Look again at your answers to Question 1, then t r y to explain why t h i s area was not ice-covered. 5. The i s l a n d of Greenland i s s t i l l i n an ice age. Name the large area i n the southern part of the Earth which i s also ice-covered. 4. I f another ice age started, what would Canadians have to do i n order to survive? Conclusion What did you learn about i c e age Canada i n t h i s investigation? INVESTIGATION 36 Glaciers Although we are no longer i n an ice age, large areas of Canada are s t i l l covered by g l a c i e r s . In t h i s i n v e s t i g a t i o n you w i l l study how g l a c i e r s form, and the ways i n which they erode rock. Purpose: to study g l a c i e r formation and erosion. Procedure A. A g l a c i e r i s a large mass of i c e formed on land. I t i s made when snow i s compressed into i c e by the weight.of more snow on top. Write the word'glacier" and i t s d e f i n i t i o n i n your notebook. B. What happens to. an ice cube i f you h i t i t with a hammer? Near the surface of a g l a c i e r , the i c e i s b r i t t l e . I t can s p l i t to form deep crevasses (Figure 22). Why i s i t sometimes dangerous f o r mountain climbers to cross g l a c i e r s ? C. I f the ice i s deep enough, i t s form changes. Instead of being b r i t t l e , i t i s able to bend and flow slowly. Deep i n 76 Growth zone where Shrinkage zone more snow f a l l s where more snow than melts melts than f a l l s Figure 21 . Side view of a g l a c i e r . Figure 2 2 . Mountain climbers crossing g l a c i e r s should be c a r e f u l to avoid crevasses l i k e t h i s one i n the Athabaska G l a c i e r . 7 7 F i g . 23 . Alpine g l a c i e r s on Mount Fay i n Banff National Park, Alberta. F i g . 24. The snout of the Athabaska G l a c i e r , where the ic e f i n a l l y melts away. 7 8 a g l a c i e r , the pressure i s so great that the ice i s able to change shape without cracking. Because the ice near the base of a g l a c i e r can flow slowly, g l a c i e r s are able to move. Examine Figure 21 . At which end of a g l a c i e r , upper or lower, w i l l the most snow f a l l and the l e a s t snow melt? At which end of a g l a c i e r w i l l the le a s t snow f a l l and the most snow melt? Where w i l l the g l a c i e r grow larger? Where w i l l the g l a c i e r grow smaller? D. Figure 23 i s a view of an alpine g l a c i e r In Banff National Park. Does the fresh snow appear on the upper or lower part of the gl a c i e r ? What happens to the ice at the snout of the Athabaska G l a c i e r , shown i n Figure 24 ? E. (Demonstration) Make two blocks of i c e by f r e e z i n g water i n a tray. Scatter some sharp sand on the bottom of one of the trays before pouring i n the water. When the water has frozen, remove the ice" blocks from the tra y s . Rub the block of p l a i n ice across a wooden board. Does the p l a i n i c e scrape the board very much? Is i t l i k e l y that p l a i n ice can erode very much rock? Nov; rub the i c e containing sand across the board. Which scraped the board more, p l a i n Ice or i c e containing sand? Which could erode rock more e a s i l y , p l a i n i c e or i c e containing broken rock? F. Examine f i g u r e 21- As a g l a c i e r moves, the ice works i t s way into cracks i n the bedrock. Pieces of broken rock become trapped i n the ice on the bottom and sides of a moving g l a c i e r . These rocks act l i k e sandpaper to scrape at the sides and bottom of the v a l l e y , making i t wider and 7 9 to show inside the i c e Figure 2 5 . A v a l l e y g l a c i e r . Figure 26. The two p i l e s of rock are l a t e r a l moraines formed by the Emerald G l a c i e r i n Yoho National Park, near the v i l l a g e of F i e l d , B.C. 80 Figure 2 7 . The medial moraines show c l e a r l y on the Coronation G l a c i e r , located on B a f f i n Island i n the Canadian a r c t i c . (Photograph courtesy of the Geological Survey of Canada). 81 deeper. A l l of the rock c a r r i e d by a g l a c i e r i s c a l l e d moraine. Write t h i s v/ord and i t s meaning i n your report. Some moraine i s f i n e r than f l o u r . Other moraine i s made up of huge boulders. G. Examine Figure 25. Moraine c a r r i e d along the side of a g l a c i e r i s c a l l e d l a t e r a l moraine. Where two g l a c i e r s come together, t h e i r l a t e r a l moraines j o i n to form a medial moraine. Write these terms and t h e i r meanings i n your report. By c a r e f u l l y counting the spaces between l a t e r a l and medial moraines, i t i s possible to f i n d the number of smaller g l a c i e r s that have flowed together to make a large g l a c i e r . How many g l a c i e r s have come together to form the g l a c i e r i n Figure 27? Questions 1. Why are v a l l e y g l a c i e r s sometimes c a l l e d " r i v e r s of ice"? 2. I f possible, examine a sample of rock over which a g l a c i e r once flowed. Explain how the grooves on i t s surface were formed. 3. a) As a g l a c i e r melts away at i t s snout, what happens to the large pieces of moraine that i t c a r r i e s ? b) What w i l l happen to the smallest pieces of moraine, c a l l e d " g l a c i a l f l o u r " , as the g l a c i e r melts? c) Why are streams which flow away from g l a c i e r s u s u a l l y f u l l of f i n e sediment? Conclusion What are g l a c i e r s , and how do they erode rock? 82 Figure 28. Landforms produced by g l a c i a l erosion. Figure 2 9 . A g l a c i e r once flowed down the v a l l e y of Leckie Creek i n the Bridge River area of B r i t i s h Columbia. (Photograph courtesy of the Geological Survey of Canada;. 83 INVESTIGATION 57 G l a c i a l Landforms Most of B r i t i s h Columbia was covered by i c e d u r i n g the i c e age. Many of our mountains s t i l l have g l a c i e r s on them today. As a r e s u l t , many of the landforms we see around us are a r e s u l t of g l a c i a l e r o s i o n . I n t h i s e x e r c i s e , you w i l l l e a r n how some of these landforms were produced. Purpose: to examine the e f f e c t s of g l a c i a l e r o s i o n . Procedure A. Look at Fi g u r e 29, showing the v a l l e y of L e c k i e Creek, where a g l a c i e r once flowed. Does t h i s v a l l e y have a V-shape or a U-shape? What w i l l g r a d u a l l y happen t o the shape of the v a l l e y i f the stream i n i t continues t o flow? B. F i g u r e 28 shows a number of landforms produced by g l a c i a l e r o s i o n . A c i r q u e i s a deep hollow carved i n the s i d e of a mountain by i c e . Write t h i s term and i t s meaning i n your notebook. How does snow enter a c i r q u e ? What causes the i c e t o leave a cirqu e ? E x p l a i n how the i c e makes a ci r q u e l a r g e r . How many c i r q u e s are there i n F i g u r e 30? C. An aret e i s a h i g h rock r i d g e formed between two c i r q u e s or g l a c i a l v a l l e y s . Write t h i s term and i t s meaning i n your notes. How many a r e t e s are v i s i b l e i n F i g u r e 31? D. A horn i s a pyramid shaped peak, formed when g l a c i e r s erode s e v e r a l s i d e s of a mountain. Write t h i s term and i t s meaning i n your notes. How many horns are v i s i b l e i n F i g u r e 31 ? E. A hanging v a l l e y i s formed when a g l a c i e r has eroded the end of a s m a l l e r v a l l e y , l e a v i n g a steep c l i f f . Sometimes a w a t e r f a l l f l o w s over the c l i f f . W r i t e the term" "hanging 84 F i g . 31. Glaciers shaped these mountains and v a l l e y s i n G l a c i e r National Park i n the S e l k i r k Mountains between Revelstoke and Golden, B.C. 85 F i g . 3 2 . Howe Sound i s a f i o r d near Vancouver, B.C. F i g . 33.. As the land around Hudson Bay rebounded upwards a f t e r the l a s t ice age, the sea formed t h i s succession of "raised beaches". 86 F i g . 34 . Ice age g l a c i e r s polished these rocks alon, the shores of Howe Sound, north of Vancouver, B.C. 87 v a l l e y " and i t s meaning i n your notes. How many hanging v a l l e y s are v i s i b l e i n Figure 3 1 ? F. During the i c e age, g l a c i e r s stretched many kilometres from the coast of B r i t i s h Columbia, out into the ocean. As they melted, ocean water flowed into the g l a c i a l v a l l e y s , forming long, narrow i n l e t s . These i n l e t s are c a l l e d f i o r d s . Write t h i s term and i t s meaning i n your notes. In Figure 32 you can see a picture of Howe Sound, a f i o r d near Vancouver. Why do f i o r d s make good harbours? Exp l a i n why there are not many good sandy beaches along the sides of f i o r d s . What i s the name of the long f i o r d j u s t north of Port Moody? (Post and Lachapelle, 1 9 7 1 ) G. During the i c e age, the t e r r i f i c weight of the i c e pushed down the land. Aft e r the i c e melted, the land slowly rose up again. I f t h i s happened along a coast where the sea could make beaches, the r i s i n g of the land would gradually l i f t these beaches above sea l e v e l . These ancient beaches, now l i f t e d above the present l e v e l of the sea are c a l l e d r a i s e d beaches. Write t h i s term and i t s meaning i n your notes. Figure 33 shows a number of r a i s e d beaches near Hudson Bay. A c a r e f u l observer i n North Vancouver can f i n d evidence of r a i s e d beaches there. (Eisbacher, 1 9 7 3 ) Questions 1 . Explain why a r i v e r v a l l e y may be V-shaped, while a g l a c i a l v a l l e y may be U-shaped. 2 . What caused the sea l e v e l to be much lower during the ice age than i t i s now? 3 . Examine Figure 3 4 . Explain how a g l a c i e r could produce 88" such a smooth p o l i s h on hard rock. Conclusion What have you learned about g l a c i a l landforms i n t h i s exercise? Part 2 The second part of t h i s proposed curriculum covers material more abstract and mathematical than that presented i n Part 1. As a r e s u l t , i t i s considered more appropriate f o r older students, and i s therefore aimed at those i n Grade 10. In the order presented, the main topic areas are: earth structure, earth history, volcanism, earthquakes, plate t e c t o n i c s , and earth resources. The p r i n c i p a l focus of Part 2, p a r t i c u l a r l y i n the sections on volcanism, earth-quakes and plate t e c t o n i c s , i s to give the student an appreciation of the dynamic nature of the Earth, and a knowledge of how i t has changed i n the past and w i l l probably continue to change i n the f u t u r e . As i n Part 1, Part 2 also contains a regional bias towards B r i t i s h Columbia. Earth Structure When designing a junior earth science curriculum, i t i s important to avoid a "can't see the f o r e s t f o r the trees" approach. That.is, one must avoid dwelling upon s u r f i c i a l aspects of the topic such as rock i d e n t i f i c a t i o n f o r example, at the expense of a discussion of the Earth as a whole. Most texts written f o r j u n i o r science students, 89 ( e . g . R a m s e y e t a T , 1978), d o c o n t a i n - a d e s c r i p t i v e s e c t i o n o n t h e i n t e r n a l s t r u c t u r e o f t h e E a r t h , u s u a l l y i l l u s t r a t e d w i t h a c u t - a w a y d i a g r a m . N o n e o f t h o s e c o n s u l t e d h o w e v e r , a p p e a r t o h a v e a n a c t i v i t y a s s o c i a t e d w i t h t h e d e s c r i p t i o n . I n v e s t i g a t i o n 1 o f t h e p r o p o s e d c u r r i c u l u m ( b e l o w ) i n v o l v e s a n a c t i v i t y w h i c h , t h o u g h s i m p l e , a p p e a r s t o b e e f f e c t i v e i n i n c r e a s i n g t h e s t u d e n t s ' a w a r e n e s s o f t h e r e l a t i v e t h i c k n e s s o f t h e v a r i o u s l a y e r s o f t h e E a r t h . B a s i c a l l y , t h i s i n v o l v e s n o t h i n g m o r e t h a n p r o v i d i n g t h e s t u d e n t s w i t h t h e d a t a r e q u i r e d t o d r a w t h e i r o w n d i a g r a m o f t h e * E a r t h ' s i n t e r n a l s t r u c t u r e . T h i s s e c t i o n o n e a r t h s t r u c t u r e c o n t i n u e s w i t h a n a c t i v i t y c o n c e r n i n g a c o m p a r i s o n b e t w e e n t h e t h i c k n e s s o f t h e l i t h o s p h e r e a n d t h e s i z e s o f a n u m b e r o f s u r f a c e f e a t u r e s , a n d a n a r r a t i v e d e s c r i b i n g t h e a t m o s p h e r e . T h e s e m a y b e r e f e r r e d t o i n t h e A d d e n d u m . T h e f o l l o w i n g p a g e s c o n t a i n t h e i n v e s t i g a t i o n o f t h e l a y e r s o f t h e E a r t h r e f e r r e d t o a b o v e . I N V E S T I G A T I O N 1 I n s i d e t h e E a r t h S t u d i e s o f t h e E a r t h , m a i n l y t h e a n a l y s i s o f e a r t h q u a k e w a v e s , h a v e s h o w n u s t h a t t h e i n t e r i o r o f t h e p l a n e t i s p r o b a b l y m a d e u p o f a s e r i e s o f l a y e r s , l i k e t h e l a y e r s i n a n o n i o n . I f we i n c l u d e t h e w a t e r a n d a i r s u r r o u n d i n g t h e p l a n e t , t h e n we c a n s u m m a r i z e t h e i n f o r m a t i o n i n a s h o r t l i s t . 1. A t m o s p h e r e : t h e b l a n k e t o f a i r s u r r o u n d i n g t h e p l a n e t . 9 0 2. Hydrosphere: the layer of water covering parts of the surface.. 3 . Lithosphere: the rocky crust on the surface of the Earth, up to 160 km thi c k . 4. Asthenosphere or Upper Mantle: the s l i g h t l y -f l e x i b l e layer upon which the crust moves, up to 560 km th i c k . 5- Lower Mantle: the rocky inner layer of the mantle, probably 2200 km th i c k . 6. Outer core: the l i q u i d l a y e r of the core, probably-made of molten i r o n , about 2250 km th i c k . 7. Inner core: the s o l i d centre of the Earth, probably made of i r o n , with a radius of 1200 km.(Press, Siever, 1978) Purpose: to draw a scale diagram of the layer s inside the Earth. Procedure A. Summarize the information given above by completing the following table i n your notes. Layer Thickness (km) Depth of top from surface of Earth (km) Distance of top from centre of Earth (km) Lithosphere 0 Asthenosphere Lower Mantle Outer Core Inner Core 1200 B. Using a f u l l page, and a su i t a b l e scale such as 1 mm = 100 km, draw with a compass a s e r i e s of c i r c l e s representing the layers of the Earth. Use the numbers i n the l a s t column of your table to set your compass f o r each 91 l a y e r . Label each layer i n your diagram. Conclusion What have you learned about the Earth i n t h i s exercise? Earth History This section of the proposed curriculum continues and extends the study of earth h i s t o r y that was started i n Part 1. I t begins with a d e s c r i p t i o n (Narrative 4, Addendum) of the o r i g i n and development of the Earth, s t a r t i n g with the cold accretion theory, and continuing with the molten earth theory to account f o r the planet's i n t e r n a l l a y e r i n g . This i s followed by an exercise i n which notable events of the past 4.6 b i l l i o n years are p l o t t e d on a time scale model, and a d e s c r i p t i o n of the methods of radiometric dating-(Investigation 5, Narrative 6, Addendum). A lengthy exercise on p r e h i s t o r i c l i f e i s found i n Investigation 7 (below). Since f o s s i l s are our only evidence of l i f e i n the distant past, i t i s f e l t that students should have the opportunity to work with them d i r e c t l y , rather than merely reading about t h e i r d e s c r i p t i o n s . The specimens chosen are those frequently found i n B r i t i s h Columbia, and general descriptions of f o s s i l l o c a l i t i e s within the province are given. . Investigation 8 (Addendum) provides the student with a simulation exercise on the way i n which a pale o n t o l o g i s t might work i n r e l a t i n g apparently d i s s i m i l a r f o s s i l s . Narrative 9 (Addendum) gives a d e s c r i p t i o n of the h i s t o r y of l i f e , from Precambrian algae through to Cenozoic primates. 92 Narrative 1 0 (below) presents another unique feature of t h i s proposed curriculum - an attempt to deal d i r e c t l y with the dispute between evolution and creatio n . While e v o l u t i o n i s t s "may point out quite c o r r e c t l y that the c r e a t i o n i s t viewpoint has no place i n a science text, they can not deny that a substantial portion of the public does believe i n s p e c i a l creation, and that i t i s sometimes d i f f i c u l t to ignore t h i s group. Some texts (Jackson &. Evans, 1 9 7 3 ) s k i r t around the problem i n an attempt to please both sides, while others (Schmid, 1 9 7 0 ) avoid the problem e n t i r e l y . This proposed curriculum meets the issue head on by c l e a r l y presenting both sides of the controversy i n p a r a l l e l n a rratives. The two sides are presented e n t i r e l y dispassionately, with no attempt to influence the reader. As a r e s u l t of t h i s approach, the teacher may use the section as a basis f o r c l a s s discussion without being accused of attempting to undermine the moral authority of the students' parents. This section on earth h i s t o r y ends (Inve s t i g a t i o n 1 1 , Addendum) with a review of sedimentary rocks, the study of which began i n Part 1 . The following pages contain the exercises r e f e r r e d to above. The remainder may be found i n the Addendum. 95 I N V E S T I G A T I O N 7 P r e h i s t o r i c L i f e Probably everyone i n your class has heard of the dinosaurs. How do we know they existed? In Investigation 5, approximate times were given f o r the f i r s t appearance of various l i f e forms. How could these have been determined? No written records of these times e x i s t , and so f a r as we know, no-one has yet invented a time machine to allow us to t r a v e l into the distant past. Our only evidence f o r the existence of these long extinct creatures comes from f o s s i l s . A f o s s i l i s the preserved remains of p r e h i s t o r i c l i f e . In t h i s i n v e s t i g a t i o n , you w i l l examine a number of f o s s i l s s i m i l a r to those found i n v/estern Canada to see what types of animals and plants once l i v e d here. The study of f o s s i l s 94- . and ancient l i f e i s c a l l e d paleontology. Purpose: to use f o s s i l s to study some of the p r e h i s t o r i c l i f e of western Canada. Procedure Part 1 Examining F o s s i l s A. Copy the data table below into your notes. Plants Animals Examine each of the specimens, or the photographs i n Figures 3 5 to 44 , then write i t s name i n the appropriate column of your ta b l e . Are most of the animals creatures which l i v e d on land or i n the sea? How do we know that large areas of western Canada were once covered by ocean? B. The t r i l o b i t e (Figure 3 5 ) was an animal which crawled or swam along the bottom of shallow seas. I t had a tough upper s h e l l (the dorsal shield) l i k e a modern day l o b s t e r . I t s underside was s o f t . T r i l o b i t e f o s s i l s are common i n the Rocky Mountains near the v i l l a g e of F i e l d , B r i t i s h Columbia. Make a sketch of a t r i l o b i t e i n your notes. The l i n e s on: the dorsal s h i e l d probably represent f l e x i b l e j o i n t s . Of what use might f l e x i b l e j o i n t s be? Usually, only, the impression of the dorsal s h i e l d i s f o s s i l i z e d . What do you suppose might have happened to the remainder of the animal? T r i l o b i t e s became extinct near the end of the Paleozoic Era. About how many years ago was t h i s (see In v e s t i g a t i o n 5 ) ? Make a l i s t of three modern sea animals which may be descended from the t r i l o b i t e s . C. The sharks (Figure 56) are one of the oldest species of 9 5 sea animals. They have been i n existence f o r about 400 m i l l i o n years. Sharks do not have a true bony skeleton. Their skeleton consists of s t i f f c a r t i l a g e , s i m i l a r to the material/which s t i f f e n s the end of your nose. Shark f o s s i l s are not common i n western Canada. Sketch the shark tooth. Describe how i t s shape d i f f e r s from the shape of a human front tooth. How does i t s shape d i f f e r from that of a human back tooth? What does the shape of the tooth t e l l you about the type of food, that a shark eats? Try to give a reason why shark teeth are frequently the only part of the animal which i s f o s s i l i z e d . D. The ammonites (Figure 3 7 ) were sea animals which were common during the Mesozoic Era. The i n s i d e s of t h e i r s h e l l s were divided into a number of closed compartments. The animal i t s e l f l i v e d i n the last; section at the outer end of the c o i l . Some of the empty compartments were f i l l e d with gas, keeping the ammonite a f l o a t i n the water. The ammonite was equipped with tentacles with which i t captured i t s prey. Many ammonite f o s s i l s have been found on Vancouver Island. Other areas of B r i t i s h Columbia, such as Manning Park, Nelson, and Telegraph Creek also have rocks which contain ammonite f o s s i l s . Sketch the ammonite s h e l l . Draw i n a number of tentacles as you think they might have appeared when the animal was a l i v e . Name a modern day sea animal, also equipped with tentacles, which may be r e l a t e d to the ammonites. E. At f i r s t , man;/ people mistake the c r i n o i d (Figure 3 8 ) f o r a plant. In f a c t i t i s an animal which i s attached to the 96 F i g . 35 . These t r i l o b i t e s once swam i n a shallow sea which covered a large area of western North America. 1 cm i i F i g . 3 6 . Shark tooth. 9 7 F i g . 38. Two pieces of c r i n o i d stem. 98 1cm • • 9. F i g . 39. Brachiopod f o s s i l s are common i n the Rocky Mountains of eastern B r i t i s h Columbia. F i g . 40. These pelecypods l i v e d near beaches i n south-western B r i t i s h Columbia at the end of the l a s t i c e age. The animal on the r i g h t was k i l l e d and eaten by a type of gastropod c a l l e d a " d r i l l " . 99 WB&mp F i g . 4-1. Gastropod s h e l l . 1 cm • F i g . 4-2. This i s a piece of the backbone of a small r e p t i l e which l i v e d i n Alberta about 7 0 m i l l i o n years i cm 100 F i g . 4-3. A piece of r e p t i l e bone, gradually weathering out of the rock i n which i t was f o s s i l i z e d . * F i g . 4 4 . Carbonized leaves found near Princeton, B.C. Similar plants are found l i v i n g on the coast of our province today. 101 bottom, of the ocean by a f l e x i b l e stem. At the top of the stem i s a bulb-shaped animal with long feathery branches. I t feeds upon microscopic animals and plants f l o a t i n g i n the water. Crinoids are s t i l l common today, l i v i n g i n cl e a r , moderately deep water. They are sometimes c a l l e d "sea l i l i e s " because of t h e i r resemblance to plants. F o s s i l i z e d c r i n o i d stems are common i n the Rocky Mountains. Sketch the c r i n o i d stem. F. Brachiopods (Figure 39,) were she l l e d animals which were very common i n the seas during the Paleozoic and Mesozoic Eras. Only a few species survive today. At f i r s t glance, they may appear to be s i m i l a r to clams, but t h e i r i n t e r n a l organs are completely d i f f e r e n t . Like clams however, they feed upon microscopic p a r t i c l e s i n the water. Brachiopod f o s s i l s may be found i n the Rocky Mountains. Sketch a brachiopod. Explain how i t s shape d i f f e r s from the shape of a pelecypod (Figure 4-0). G. The pelecypod group includes clams, s c a l l o p s , oysters, and many other bivalyed (two shelled) sea animals. They have been common since the Paleozoic Era, and thousands of species may be found i n the seas today. Pelecypods feed upon microscopic p a r t i c l e s f l o a t i n g i n the water. F o s s i l s may be found i n the Fraser Va l l e y , i n cla y banks which were once beaches hear the end of the l a s t i c e age. They are also common i n Mesozoic sandstone on the Queen Charlotte Islands and southern Vancouver Island. Sketch two d i f f e r e n t types of pelecypod s h e l l . Name four d i f f e r e n t edible pelecypods. 102 H. Gastropods (Figure 4-1) are s n a i l s . These have been common since the Paleozoic Era, l i v i n g both on land and i n the water. The animal has a single s h e l l , c o i l e d i n t o a c o n i c a l s p i r a l . Some gastropods feed on plants, while others attack and eat other s h e l l e d animals. Gastropod f o s s i l s are found i n the same areas as the pelecypods mentioned i n Procedure G. Sketch the gastropod f o s s i l . Are some gastropods edible? Gastropod and ammonite s h e l l s are both c o i l e d . What i s the main difference i n t h e i r •shape? I. P e t r i f i e d r e p t i l e bone (Figure 4-2) i s very hard, and usually brownish i n colour. Occasionally, whole skeletons have been found i n Mesozoic rocks of Alberta.(Figure 4-3).'.No v specimens have yet been found i n the Mesozoic rocks of Vancouver Island. Sketch a piece of r e p t i l e bone. How can you t e l l that i t has been p e t r i f i e d ? In what ways does i t resemble present day bone? J . Leaves (Figure 4-4-). Land plants f i r s t appeared i n the Paleozoic Era, about 44-0 m i l l i o n years ago. Some of the f i n e s t l e a f f o s s i l s i n Canada are found i n the buff coloured shale (see Investigation 11) beds near Princeton i n southern B r i t i s h Columbia. These were formed about 20 m i l l i o n years ago. Sketch two f o s s i l leaves, one broad l e a f and one c o n i f e r l e a f . Why do you suppose that unbroken f o s s i l leaves are quite rare? Examine Figure 44, and by studying the types of leaves t r y to describe the climate near Princeton about 20 m i l l i o n years ago. Use a reference book to help you 103 write a short paragraph describing how coal i s formed. K. P e t r i f i e d wood (Figure 45). Wood may be f o s s i l i z e d i n two d i f f e r e n t ways. Examine your specimens and describe the appearance of each. What evidence i s there that each was once a piece of wood? (Nelson, 1970; Tidwell, 1975). Part 2 How F o s s i l s are Formed A f o s s i l i s formed (Figure 4-6) when the body of an animal i s r a p i d l y covered over with sediment such as mud or sand. I f more sediment i s deposited on top over the years, the pressure w i l l harden the sediment below in t o rock. Eventually, m i l l i o n s of years l a t e r , weathering and erosion may wear away the overlying rock, exposing the f o s s i l to view. Before i t i s exposed, the f o s s i l may be a l t e r e d i n a number of d i f f e r e n t ways, leading to a number of d i f f e r e n t types of preservation. a) Actual preservation. Although t h i s i s very rare, i t can occur when b a c t e r i a l action and decay have been stopped. An entire Musk ox, recovered from the i c e and permafrost of Alaska i s an excellent example (Guthrie, 1972). Other animals have been preserved i n bogs and t a r p i t s . b) Permineralization. Minerals from ground water gradually f i l l i n the a i r spaces i n bones. This tends to make the bone heavier, without changing i t s o r i g i n a l shape or s i z e . Many dinosaur skeletons have been preserved i n t h i s way. c) Replacement. The o r i g i n a l s h e l l or skeleton.is dissolved away, one atom or molecule at a time, and replaced 104-5 cai i F i g . 4-$. S i l i c i f i e d wood. I t i s s t i l l possible to the rings of the o r i g i n a l t r e e . a) Death. b) B u r i a l i n sediment c) Hardening into d) Exposure, rock. Figure 4-6. Formation of a f i s h f o s s i l . 1 0 5 by a d i f f e r e n t material. Wood i s frequently " p e t r i f i e d " i n t h i s manner, when the wood i s replaced by s i l i c a ( s i l i c o n dioxide, Si02)» d) Carbonization. The hydrogen and oxygen atoms from the o r i g i n a l material are l o s t , leaving only black or brown carbon atoms behind. Leaves are often f o s s i l i z e d i n t h i s way. e) Moulding and casting. The o r i g i n a l s h e l l or bone i s completely dissolved by ground water. The c a v i t y l e f t behind i s c a l l e d a mould. If the mould i s l a t e r f i l l e d with another material, the r e s u l t i n g f o s s i l forms a cast. S h e l l s are frequently f o s s i l i z e d as moulds or casts. f ) Tracks of animals may be f o s s i l i z e d i f the soft mud i n which they are made hardens in t o rock. Dinosaur tracks from the Peace River area of northeastern B r i t i s h Columbia are displayed outside the P r o v i n c i a l Museum i n V i c t o r i a . g) Coprolites are f o s s i l i z e d excrement or dung. Analysis of these can t e l l us much about the eating habits of early l i f e . (Casanova, 1 9 5 7 ) L. Copy the data table belov; into your notebook. Examine each of your specimens, then l i s t i t s name and i t s method of preservation i n your ta b l e . Specimen Name Method of Preservation Part 3 Uses of F o s s i l s The most e x c i t i n g use of f o s s i l s i s the obvious one. They are our only evidence of the type of organisms which 106 Figure 49. Outline map of B r i t i s h Columbi 1 0 7 once inhabited the Earth. By c a r e f u l examination of the f o s s i l s within a layer of rock, a paleontologist can reconstruct what l i f e may have been l i k e on an ocean bottom hundreds of m i l l i o n s of years ago. He can describe from t h e i r bones, the dinosaurs tha^t once roamed western Canada. If he i s lucky, he may even be able to trace the ancestry of some of the species of animals and plants l i v i n g today. Geologists working f o r o i l companies study m i c r o f o s s i l s (very small f o s s i l s ) c a r e f u l l y . They know that c e r t a i n of these are associated with o i l . When they f i n d these micro-f o s s i l s i n a layer of rock, they know that o i l may be nearby. By examining f o s s i l s i n la y e r s of rock, a geologist can also f i n d out what rocks may have been i n a p a r t i c u l a r place before they were removed by erosion. M. Trace the diagram of the canyon i n Figure 4-7 into your notebook. Match up the f o s s i l s on both sides of the canyon, then draw l i n e s across the canyon to show how the layers might have looked before the r i v e r eroded them away. Questions 1 . What i s a f o s s i l ? 2. Name each of the f o s s i l s sketched In Figure 4-8. 3. Name the type of f o s s i l i z a t i o n which occurred i n each case: a) A mouse i s buried i n volcanic ash. Water di s s o l v e s the body, leaving a c a v i t y . . b) A " p e t r i f i e d tree" made of s i l i c a i s found. c) A s h e l l i s buried, then disso l v e d away. The ca v i t y i s f i l l e d with f i n e sand which hardens in t o sandstone. d) A black outline of a willow l e a f i s found p r i n t e d 108 on very f i n e grained rock near Princeton, B.C. 4-. Explain why f o s s i l s are seldom found i n volcanic rocks. 5. How can f o s s i l s t e l l us about the climate i n the past? 6. From Figure 4-9, trace the outline map of B.C. into your . notebook. Make a numbered key of the f o s s i l l ocations mentioned i n Part 1 of t h i s i n v e s t i g a t i o n . Use an at l a s to help you f i n d these l o c a t i o n s , and mark them on your map. NARRATIVE 10 Evolution or Creation? - The Controversy So f a r , we have looked at only one theory of the o r i g i n and development of our Earth and the l i f e upon i t . Other l e s s popular theories e x i s t , among them the theory of "Special Creation". In t h i s narrative we w i l l consider b r i e f l y some of the claims made f o r both the o r i e s . Evolution The o r i g i n of the universe i s a mystery. The sun and planets formed over a period of several m i l l i o n years from a cloud of dust and gas i n our galaxy. This took place about f i v e , b i l l i o n years ago. Naturally occurring processes produced the chemical b u i l d i n g blocks of l i f e i n the oceans. By a complex process, the Spec i a l Creation A divine being (God) has existed forever, and created the universe. God created the universe, i n c l u d i n g our Earth, during a period of s i x 24—hour days. This took place several thousand years ago. During the s i x days of creation, a l l the. l i f e forms we know about were created i n the exact form we see them .109 b u i l d i n g blocks group together into droplets and develop the a b i l i t y to carry on chemical reactions within themselves. The droplets are said to be " a l i v e " when they are able -to manufacture exact copies of themselves. During t h i s time, about a b i l l i o n years, the geological processes of weathering, erosion, mountain b u i l d i n g etc. are carrying on at about the same rate as they are today. Mutations cause changes i n genes which produce new species. Those organisms better able to f i n d food and reproduce themselves survive. Those which compete unsuccessfully become extinct. today. A vast global f l o o d , recounted i n the Bi b l e by Noah, produced worldwide geological e f f e c t s . Weathering and erosion occurred much f a s t e r than they do now because of the tremendous amount of water that was moved around. Many species of plants and animals were exterminated. Many f o s s i l s were formed at t h i s time, as well as huge deposits of coal and o i l . Those organisms which survived the f l o o d . r e - e s t a b l i s h themselves. 110 The controversy between the two sides of t h i s argument has been strong since 1859- In that year, Charles Darwin published h i s famous book, "On the O r i g i n of Species", recounting his idea of evolutionary development. Since then, Darwin's theory has been developed further, and modified by the discovery of Mendel's Laws and our understanding of what happens within c e l l s during reproduction. S c i e n t i s t s and churchmen on both sides of the argument claim that both the geological evidence and the f o s s i l record prove that t h e i r viewpoint i s true, and that the opposing viewpoint i s f a l s e . The evidence which both e v o l u t i o n i s t s and c r e a t i o n i s t s use to support t h e i r views i s very complex. I f , during the next few years, you wish to study the problems of the o r i g i n of the Earth and the development of l i f e f u r t h e r , ask your teachers to recommend books which present both sides of the story as f a i r l y as po s s i b l e . (Nelkin, 1976; Morris, 1970) Questions 1. Which do you prefer, evolution or s p e c i a l creation? Write a short essay explaining and supporting your p o s i t i o n . Volcanoes There are several reasons why students should learn about volcanoes during a course on earth science. One i s the i n t r i n s i c i n t e r e s t of volcanoes to j u n i o r students, as objects of violence, fear and beauty. Another i s the h i s t o r i c place that volcanoes hold i n the development of plate 111 tectonic theory. Yet another reason i s that whether they know i t or not, B r i t i s h Columbia residents inhabit one of the major ( i f presently i n a c t i v e ) volcanic areas of the Earth - a 1 5 0 0 km segment of the s o - c a l l e d " P a c i f i c Ring of F i r e " - and f a m i l i a r i t y with the landscape of the province must therefore include f a m i l i a r i t y with i t s volcanoes. Very few students w i l l dispute the f a c t that the i n t e r i o r of the Earth i s hot, but few i f any could make a quantitative statement about i t s temperature. The f i r s t exercise i n t h i s section, Investigation 1 2 (below) provides, the student with actual subsurface temperature readings from two widely separated areas of the Earth. By p l o t t i n g graphs and making simple c a l c u l a t i o n s , the student i s able to determine a depth at which rock could be molten. Once the f a c t that the i n t e r i o r of the Earth i s very hot has been established, Narrative 1 3 (below) brings out some possible uses of t h i s heat. This passage on geothermal energy points out to the student the uses, b e n e f i t s , and drawbacks of present technology, and describes the current status of geothermal exploration i n B r i t i s h Columbia, information unavailable i n any other j u n i o r science text consulted. Next, the student i s introduced to various types of volcanoes, ( I n v e s t i g a t i o n a l 4 , Addendum), and to a number of volcanic landforms. Considering the present lack of active volcanism i n B r i t i s h Columbia, a knowledge of landforms i s e s s e n t i a l i n order f o r the t r a v e l l i n g student to appreciate 112 the volcanic nature of t h i s province. Investigation 1 5 (Addendum) lays the groundwork f o r plate tectonic theory by having the students p l o t the positions of a number of volcanoes on a world map, thereby "discovering" that they are not randomly positioned, but form a d e f i n i t e pattern. Narrative 16 (below) returns the student ot B r i t i s h Columbia with a d e t a i l e d d e s c r i p t i o n of three volcanic areas of the province, i l l u s t r a t e d with a number of excellent photographs unavailable i n any other text. F i n a l l y , the section concludes with a review of igneous and metamorphic rocks (Inv e s t i g a t i o n 1 7 , Addendum), a topic begun i n Part 1, and an explanation of the theory of the rock cycle (Narrative 18, Addendum). The following pages include the student exercises r e f e r r e d to above. The remainder may be found i n the Addendum. INVESTIGATION 12 Heat Within the Earth Would you l i k e to be a South A f r i c a n gold miner? The depths of the mines are so hot that the workers have to be t r a i n e d i n steam baths! Those who can not withstand the high temperatures and humidity are unable to work i n the mines. Have you ever swum i n the water from a hot spring? There are many hot springs i n western Canada. Banff, Radium and Harrison are probably the best known. The gold mines of South A f r i c a , and the hot springs of western Canada provide plenty of evidence that the i n t e r i o r of the Earth i s hot. But how hot i s i t ? In t h i s exercise you w i l l determine just how deep we would have to go to f i n d molten rock. Purpose: to calcu l a t e a geothermal gradient, and apply i t to f i n d i n g the depth of molten rock. Procedure A. The introduction to t h i s i n v e s t i g a t i o n gives two pieces of evidence that the i n t e r i o r of the Earth i s hot. Describe a t h i r d example that you may have heard of. B. Below i s a l i s t of temperatures recorded at various depths i n two widely separated areas of the world, a South A f r i c a n gold mine and an Icelandic f i s h i n g v i l l a g e . Western Deep Gold Mine Vestman Islands (South A f r i c a ) (Iceland) Depth (km) Temperature ( °C) Depth (km) -.Temperature (°C) 0 18 0 10 0 . 5 2 3 0 . 2 2 3 1 . 0 2 9 0 . 4 36 1 . 6 3 5 0 . 6 4 7 1 . 9 3 8 0 . 8 59 2 . 7 46 1 . 0 72 3 . 5 5 4 1 . 2 80 3 . 8 5 8 1 . 4 9 0 (White 1 9 7 4 ) (Palmason 1 9 7 0 ) these two sets of values separately on the same graph, using the top l e f t hand corner as the o r i g i n (Figure 5 0 ) . Draw a smooth l i n e through each set of points. Label each l i n e as "South A f r i c a " or "Iceland". 114 Temperature (°C) no 10 20 30 4-0 50 60 70 80 90 100 V r 1 > • » : 1 1 1 1 • 1 1 . ., S. 4 L Figure 50 . Graph axes f o r Procedure B. 0 10 20 &*° 50 Temperature ( C) 0 1000 2000 3000 4000 s -k 1 • k-60 Figure 51. Graph axes f o r Procedures G and I. C. The geothermal gradient i s the average amount of temperature increase f o r each kilometre of depth. I t i s expressed i n "degrees Celcius per kilometre", (°C/km). Write the term geothermal gradient and i t s meaning i n your notebook. D. From the graphs you drew i n Procedure B, c a l c u l a t e the geothermal gradient f o r each area by t h i s method: choose one depth on each l i n e and f i n d the temperature at that depth. Use those f i g u r e s i n t h i s formula: geothermal, (depth temperature)-(surface temperature)_ Op/^ gradient. " (depth) " — U / K m Which area has the higher geothermal gradient, South A f r i c a or Iceland? E. Now you w i l l use your r e s u l t s from Procedure D to estimate the temperature at greater depths. To f i n d the temperature at any depth, multiply the geothermal gradient by the depth. What i s the estimated temperature at a depth of 10 km i n South A f r i c a ? What i s the estimated temperature at a depth of 10 km i n Iceland? F. Copy the tables below i n t o your notebook. Using the method of Procedure E, complete the temperature column i n each t a b l e . South A f r i c a / Iceland Depth (km) Temperature (°C) Depth (km) Temperature (°C) 0 0 0 10 10 20 20 30 30 4-0 4-0 50 50 60 60 G. Using the data from Procedure F, plot, another graph 116' s i m i l a r to the one you plo t t e d i n Procedure B. Figure 51 shows you how to draw the axes. Label each l i n e with the l o c a t i o n . i t represents. H. Examine each of the two rock samples. Granite i s t y p i c a l of rocks found i n coastal B r i t i s h Columbia. Basalt i s found i n many volcanic areas of the Earth. Write a b r i e f d e s c r i p t i o n of the appearance of each sample. I. Below are tables of the melting temperatures of granite, and basalt at various depths. P l o t the two sets of points on the graph you drew i n Procedure G. Draw a smooth l i n e through each set of points, and l a b e l each l i n e with the name of the rock i t represents. Granite Basalt Depth (km) Melting Depth (km) Melting Temperature ( C) Temperature ( C) 0 9 0 0 0 . 1 1 0 0 1 8 9 0 1 0 1 1 3 0 5 825 2 0 1160 10 74-0 3 0 1190 2 0 7 2 0 . 40 1 2 2 0 3 0 690 50 1 2 5 0 40 680 60 1280 50 6 7 5 60 670 (Lambert 1 9 7 8 ) J . Using your graph from Procedure I, at what depth wOuld granite be molten beneath Iceland? beneath South A f r i c a ? At what depth would basalt be molten beneath Iceland? Would you expect volcanoes to be more common i n South A f r i c a or Iceland? Questions 1 . How do we know that the i n t e r i o r of the Earth i s hot? 2 . a) Using the Icelandic f i g u r e f o r the geothermal gradient, ca l c u l a t e the estimated temperature at the centre 1 1 7 of the Earth - a depth of 6360 km. b) Considering that the surface temperature of the sun i s about 6000°C (Ramsey 1 9 7 8 ) , does your value f o r the temperature at the centre of the Earth seem reasonable? c) How do we know that the temperature does not continue increasing a l l the way to the centre of the Earth? 3. a) Which country has the generally warmer climate, South A f r i c a or Iceland? b) Which has the higher geothermal gradient, South A f r i c a or Iceland? c) How do we know that the heat within the Earth has nothing to do with climate, that i t i s not caused by the heat from the sun? 4-. Design a way to obtain us e f u l work from the heat energy within the Earth. Make a sketch of your design. Conclusion What have you learned about the temperature within the Earth, and about the depth at which rock melts? NARRATIVE 1 5 Geothermal Energy Energy i s the d r i v i n g force of industry. Indeed, without energy the progress of c i v i l i z a t i o n would come to a h a l t . At present, the p o s s i b i l i t y of our f i n d i n g new sources of energy i s not good. The world's supply of f o s s i l f u e l - o i l , coal and natural gas - i s running low. Nuclear power produces extremely hazardous waste materials. Soon there w i l l be no new r i v e r s l e f t to dam f o r h y d r o e l e c t r i c energy. 118 Solar energy, wind and t i d a l power seem to be u s e f u l , but we have not yet learned how to harness them e f f i c i e n t l y . What i s l e f t ? Geothermal energy - heat energy from within the Earth. Underneath our feet, deep within the Earth, i s an almost l i m i t l e s s supply of heat energy. The i n t e r i o r of the Earth has been cooling slowly f o r about four b i l l i o n years, and yet i t i s s t i l l molten! If we could use even a small f r a c t i o n of that heat, we could solve our energy problems f o r thousands of years to come. Many methods have been devised f o r e x t r a c t i n g heat energy from the Earth. Most of these use water as a c a r r i e r f o r the heat. The simplest scheme uses a natural flow of hot water or steam from the Earth, such as a hot spring or geyser (Figure 5 2 ). Steam may be used to turn e l e c t r i c a l generators. Hot water may be used to heat homes or f a c t o r i e s . Many hot springs such as the one at Banff (Figure 5 3 ) have been developed as t o u r i s t r e s o r t s . I f the hot water or steam does not work i t s way to the surface n a t u r a l l y , i t can sometimes be reached by d r i l l i n g a w e l l . In northern I t a l y , steam wells were f i r s t d r i l l e d i n 1830. In 1904 the f i r s t experimental generation of e l e c t r i c i t y from natural steam began, and i n 1913 continuous commercial production started.' Iceland, another pioneer i n geothermal development, has been using hot water f o r heating'buildings since 1898. In the c a p i t a l c i t y of Reykjavik, over 90% of the homes now receive geothermal water f o r heating. (Press, Siever 1978). 1 1 9 ' hot spring Figure 52 . Cold ground water, heated by hot rock r i s e s to the surface to make a hot spring. 120 heat exchanger hot water water pumped back into ground cold water hot water Figure 54 . Geothermal water passed through a heat exchanger r a i s e s the temperature of clean water. The hot clean water i s then used f o r home or i n d u s t r i a l purposes. 121 Sometimes the geothermal steam and hot water contain a. l o t of dissolved minerals. I f t h i s water were used d i r e c t l y , the minerals could be deposited i n the machinery, causing i t to clog up. In t h i s case the geothermal water i s passed through a heat exchanger where i t heats clean water, then pumped back underground. The clean water i s then used f o r heating purposes. In western Canada, serious exploration f o r geothermal resources began i n 1972. Feder a l l y , the Earth Physics and Geological Survey branches of the Department of Energy, Mines and Resources have been conducting a general study of the area. P r o v i n c i a l l y , the B r i t i s h Columbia Hydro and Power . Authority are responsible f o r l o c a l exploration. B r i t i s h Columbia, with over eighty hot springs (McDonald 1978), seems to have a great deal of geothermal p o t e n t i a l . A number of hot springs i n the province have been developed f o r r e c r e a t i o n a l use since the e a r l y part of the century. Unfortunately, none of the s i t e s explored so f a r are producing enough natural steam to operate e l e c t r i c a l generators. The next stage i n development i s to d r i l l exploratory wells, possibly near Meager Mountain, 150 km north of Vancouver. I f these produce enough high energy steam, then major geothermal development could be started i n the area (Souther 1978). Unfortunately, geothermal power does have some serious drawbacks. Although the t o t a l amount of heat within the Earth i s just about l i m i t l e s s , the amount of heat a v a i l a b l e to a geothermal development can be used up. I f natural hot 122 water i s pumped out of the ground f a s t e r than i t i s naturally-replaced, then eventually the water supply- d r i e s up and power generation stops. Another problem i s p o l l u t i o n . Natural waters frequently carry dissolved sulphurous gases. Releasing these gases into the atmosphere can r e s u l t i n serious a i r p o l l u t i o n . The greatest d i f f i c u l t y with geothermal power i s the problem of using up a l l the heat i n the development area. As heat i s extracted from the rock, i t must be replaced by more heat conducted from deeper within the Earth. Heat conduction through rock i s very slow. I f heat i s extracted f a s t e r than i t i s replaced, then eventually power generation must cease. (Press, Siever 1978). Despite these d i f f i c u l t i e s however, i n some areas of the Earth, geothermal development i s an a t t r a c t i v e source of energy. Questions 1. Volcanoes are more common on the west coast of Canada than on the east coast. Explain why geothermal development i s l i k e l y to be more p r a c t i c a l on the west coast. 2. Use your r e s u l t s from Inve s t i g a t i o n 12 to explain why Iceland i s a l i k e l y place f o r geothermal development. 125 NARRATIVE 16 . Volcanoes of B r i t i s h Columbia Although B r i t i s h Columbia forms a 1600 km l i n k i n the . "Ring of F i r e " surrounding the P a c i f i c Ocean, i t s volcanic areas ( F i g . 55 ) are not well known. This i s probably because there have been no known eruptions i n B.C. within the time of recorded h i s t o r y . Legends of the Tahltan and Tsimshian indians however, t e l l of eruptions i n the northern part of the province le s s than 200 years ago. At the turn of the century, an old woman i n the area t o l d of her childhood memories of hearing thunder louder than a thousand thunder-storms, of f e e l i n g the earth shake, and watching the skies 124 .•centres of volcanic a c t i v i t y Figure 55. Cenozoic volcanoes of B r i t i s h Columbia, ( a f t e r Holland, 1964) Figure 56. Gl a c i e r s have formed i n s i d e the crater of Mount Edziza. (Photograph courtesy of B e a u t i f u l B r i t i s h Columbia Magazine). 1 2 5 F i g . 5 7 . Eve Cone i s an almost p e r f e c t l y formed cinder cone near Mount Edziza. (Photograph courtesy of Be a u t i f u l B r i t i s h Columbia magazine). F i g . 5 8 . Mount G a r i b a l d i i s a volcano which erupted on to the surface of an i c e age g l a c i e r . The p e c u l i a r f l a t -topped mountain i s c a l l e d the Table. I t was formed by lava which melted a hole i n the g l a c i e r . 126 F i g . 5 9 . The B a r r i e r i s a 2 5 0 metre c l i f f , formed when lava flowed up against an i c e age g l a c i e r . F i g . 60 . Lava b u i l t a dam across t h i s v a l l e y , which f i l l e d with water to make b e a u t i f u l G a r i b a l d i Lake. 1 2 7 F i g . 61 . The Black Tusk. This peak i n G a r i b a l d i Park was once part of a huge volcano. Now, most of the volcano has been eroded, and only t h i s hard lava flow remains. 128 F i g . 62 . Compare t h i s view of the Black Tusk with the one i n Figure 140. Every year, hundreds of hikers climb t h i s peak. F i g . 63 . A small cinder cone i n G a r i b a l d i Park. When t h i s photograph was taken, the c r a t e r at i t s summit was s t i l l f i l l e d with snow. 129 F i g . 64 . This group of climbers i s camped half way to the summit of Mount Baker. Fig« 65 . Clouds of steam pour from a c r a t e r just below the summit of Mount Baker. 1 3 0 turn red and the day turn into night from clouds of ash b l o t t i n g out the sun. Recently, geological s c i e n t i s t s have found at l e a s t three lava flows nearby which are l e s s than 1300 years o l d . Perhaps the eruption of one of these.was the one remembered by the old woman. The highest peak i n the volcanic area i s named Edziza ( F i g . 5 6 ) , which means "cinders" i n the Tahltan d i a l e c t . The lava flows surrounding Mount Edziza form a great s h i e l d over 80 km long and 16 km wide. Edziza i t s e l f i s a s t r a t o -volcano, 2788 m high, surrounded by dozens of small lava and cinder cones, craters and pumice f i e l d s ( F i g . 57 )• Recently, the 130 400 hectares surrounding Mount Edziza have been declared a p r o v i n c i a l park. The p r o v i n c i a l Parks Branch however, warns would-be v i s i t o r s that there are no f a c i l i t i e s , and that " I t i s no place f o r the i l l - e q u i p p e d , or f o r persons unable to fend f o r themselves". (Souther, 1 9 7 2 ) . In, the Mount Edziza area there are a number of hot springs with water temperatures ranging from 50°C to 75°G (Souther, Halstead 1973). The geothermal gradient i n a te s t hole d r i l l e d 8 km from the volcano was 35°C/km (Souther 1978), about h a l f the Icelandic geothermal gradient you ca l c u l a t e d i n Investigation 12. The area looked promising f o r geothermal development, but a l l exploration was stopped when the p r o v i n c i a l park was declared. In southern B r i t i s h Columbia, the best examples of volcanism are found i n G a r i b a l d i P r o v i n c i a l Park, 80 km north of Vancouver. Here, the volcanic eruptions occurred 131 between 25 000 and 10 000-years ago, at the height of the l a s t ice age. Mount Garibaldi i t s e l f i s a stratovolcano which a c t u a l l y poured lava on to the top of the i c e sheet. When the ice melted, the side of the volcano was l e f t unsupported, and i t collapsed into the v a l l e y below. Nearby i s a very strange, almost c i r c u l a r , flat-topped peak c a l l e d the Table ( F i g . 58 ). I t Is made up of h o r i z o n t a l layers of lava, l i k e the layers i n a cake. The table i s believed to have formed when lava erupting from below melted an almost c i r c u l a r hole through the overlying i c e . Near the t r a i l leading i n to G a r i b a l d i Park i s the B a r r i e r ( F i g . 59 ), a v e r t i c a l c l i f f over 250 m high. Here, lava flowing from Mount Price froze against the gigantic . ice age g l a c i e r f i l l i n g the v a l l e y . When the i c e melted, the c l i f f remained. In 1855, a 4-5 m i l l i o n tonne section broke away from the c l i f f and roared down the v a l l e y i n a massive l a n d s l i d e . Geologists think that t h i s could happen again, but are unable to say when. Behind the B a r r i e r , water f i l l e d the blocked v a l l e y , creating, b e a u t i f u l G a r i b a l d i Lake, :. ;. : shown i n Figure 60... Evidence of more ancient volcanism i s found i n the Black Tusk ( F i g s . 61 and 62 ). Once a great volcano, i t has mostly been removed by erosion. Only a p o r t i o n of a hard lava flow remains. Eventually, i t too w i l l crumble. (Mathews 1975). A volcano well known to people l i v i n g i n southwestern B r i t i s h Columbia i s Mount Baker. S t r i c t l y speaking, Mount Baker Is not i n B.C. However, many of the residents of the 132 lower Fraser Valley think of i t as " t h e i r " volcano, a s t r a t o -volcano with a height of 3316 m, i t dominates the skyline to the southeast of Vancouver ( F i g .64). Mount Baker i s l a s t known to have erupted i n 1870, when i t emitted great clouds of smoke. Recently, i n 1975, a c r a t e r near the summit started to produce large amounts of steam, and the heat melted a portion of the surrounding g l a c i e r ( F i g . 65 ) . Geologists studying the mountain stated that an eruption of lava was u n l i k e l y at that time. They were concerned however, that the increased heat could melt the snow and i c e , causing l a n d s l i d e s or mudflows. I f these were to flow into Baker Lake at the foot of the mountain, the dam at the end of the lake could be damaged. F a i l u r e of the dam would endanger the l i v e s of thousands of people l i v i n g i n the v a l l e y below. Lava flows and explosions are not the only dangers posed by volcanoes! (Harris 1976). Questions 1. What type of volcano i s Eve Cone, shown i n Figure 57? 2. What would have been the major disadvantage to geothermal development i n the Edziza area? 3. Draw a seri e s of diagrams to show how the B a r r i e r formed. 4. I f Mount Baker were to erupt, would the c i t y of Vancouver be endangered? Describe what could or could not happen. Earthquakes The reasons f o r having students l e a r n about earthquakes are s i m i l a r to those given i n the section an volcanoes. I n i t i a l l y , students seem to have a natural i n t e r e s t and 133 -: awe of the p o t e n t i a l violence of an earthquake. Secondly, earthquakes hold an imporatant h i s t o r i c a l place i n the development of plate tectonic theory. F i n a l l y , many students l i v i n g i n coastal B r i t i s h Columbia are on the.fringes of a very active seismic zone, and many of them have and w i l l experience d i r e c t l y the r e s u l t s of an earthquake. This section begins with a d e s c r i p t i o n , (Narrative 19, below), explaining to the student the r e l a t i o n s h i p between earthquakes and f a u l t movements, the meanings of the Richter Magnitude Scale and the M e r c a l l i Intensity Scale, and the d i f f e r e n c e s between the two s c a l e s . This narrative also describes the r e l a t i o n s h i p between b u i l d i n g construction and possible damage, and the p o t e n t i a l f o r hazardous earth-quakes i n Canada. While the information on f a u l t s , Richter Magnitude and M e r c a l l i Intensity may be found i n numerous c u r r i c u l a , that on the Canadian experience i s generally ava i l a b l e only i n academic, government, or u n i v e r s i t y l e v e l p u b l i c a t i o n s , sources which are d i f f i c u l t f o r the average ju n i o r high school student or teacher to consult. Since t h i s proposed curriculum i s intended to have a strong regional bias, i t was considered appropriate to include t h i s m a terial. The introductory d e s c r i p t i o n r e f e r r e d to above lays the groundwork f o r a number of laboratory i n v e s t i g a t i o n s of earth-quakes. The f i r s t of these, ( I n v e s t i g a t i o n 20, Addendum), shows the student the p r i n c i p l e s of operation of a seismograph. This i s followed ( I n v e s t i g a t i o n 21, below), by an exercise i n analysing a seismogram to locate the epicentre of an earthquake. While s i m i l a r exercises already appear i n 1 3 4 some texts, (Schmid 1 9 7 0 , Mathews 1 9 7 8 ) , none of these r e l a t e to actual earthquakes i n B r i t i s h Columbia. The event chosen f o r t h i s curriculum, a c t u a l l y occurred on the B.C. coast. Exercises on areas which the students know are close to home appear to have much greater impact than those located i n d i s t a n t lands. Following the exercise of l o c a t i n g an earthquake, the student p l o t s the pos i t i o n s of a number of h i s t o r i c earth-quake d i s a s t e r s on a world map (In v e s t i g a t i o n 22, Addendum), thereby "discovering" the pattern formed, and i t s close resemblance to the pattern of volcano l o c a t i o n s . The section ends with another d e s c r i p t i v e passage, (Narrative 23, below), gi v i n g the causes and e f f e c t s of tsunamis, and recounting the l o c a l experience of the wave caused by the great Alaska earthquake of 1964. The following pages contain the sections of the proposed curriculum r e f e r r e d to above. The remaining sections on the topic of earthquakes may be found i n the Addendum. NARRATIVE 19 . Earthquakes "Thousands K i l l e d ! " , "A C i t y Collapses!", "Gigantic Earthquake!". Every year, these and s i m i l a r headlines appear i n newspapers. Of a l l the possible natural d i s a s t e r s which can s t r i k e , a great earthquake i s perhaps the most t e r r i f y i n g . One can run away from f i r e or f l o o d , and s h e l t e r from wind or storm, but where can one hide when the Earth i t s e l f s t a r t s to shake? 1 3 5 Earthquakes are caused by movements i n the Earth's crust. One section of the crust moves past another along a . plant? C.RI 1 ed a f a u l t . Sometimes f r i c t i o n causes the two sides of the f a u l t to lock together. As movement t r i e s to continue, s t r a i n forces b u i l d up. When the built-up force i s strong enough to overcome the f r i c t i o n , the two sides of the f a u l t s l i d e past each other with gigantic "jerks".. . The r e s u l t i n g v i b r a t i o n s i n the ground are f e l t as an earthquake. On March 27, 1964, a great earthquake occurred i n Alaska. Figures 66 and 67 show one of the f a u l t s as i t cuts across the mouth of Hanning Bay. When the earthquake happened, the rock on one side of the f a u l t was l i f t e d three metres higher than the rock on the other side. In Investigation 14 you learned that small earthquakes are sometimes associated with volcanic eruptions. Figures 68 and 69 show what can happen i f a f a u l t l i n e crosses a roadway. The place v/here the rock f i r s t breaks i s frequently deep underground. Sometimes i t i s as much as 700 km beneath the surface. This l o c a t i o n underground i s c a l l e d the focus of the earthquake. On the surface, the most v i o l e n t shaking u s u a l l y occurs s t r a i g h t above the focus. This point, d i r e c t l y above the focus i s c a l l e d the epicentre of the earthquake. S c i e n t i s t s shov/ing earthquakes on maps are p l o t t i n g the p o s i t i o n s of the epicentres. The strength of an earthquake i s measured numerically i n two d i f f e r e n t ways. In the newspapers, the strength i s reported as a number on the Richter Magnitude Scale. This 136 • F i g . 66. This l i n e across Hanning Bay i s a f a u l t where the earth cracked during the 1964- Alaska earthquake. The area to the r i g h t of the f a u l t i s white with the s h e l l s of sea animals whose home was l i f t e d above sea l e v e l by the earthquake. (Photograph courtesy of U.S. Geological Survey). F i g . 67 . A c l o s e r view of the Hanning Ba^ i n Figure 66 . (Photograph courtesy of U.fc Survey). f a u l t shown Geological 137 F i g . 69 • A section of road destroyed by f a u l t i n g . 138 number between 0 and 10, i s a measure of the amount of energy a c t u a l l y released by the earthquake at i t s focus. On t h i s scale, each number represents an energy release about 30 times greater than a number one unit l e s s . Thus, an earthquake of magnitude 7.4 i s about 30 times stronger than one of magnitude 6.4. The table below r e l a t e s the Richter magnitude to an estimate of the probable damage caused.by an earthquake i n an inhabited area. Richter Magnitude Scale Magnitude 10 9 8.0 to 8.9 7.4 to 7.9 7.0 to 7-3 6.2 to 6.9 5-5 to 6.1 4.3 to 5-4 3.5 to 5.3 2.0 to 3.4 Less than 2.0 Estimated Number of Earthquakes Each Year Damage at Epicentre Possible, but never recorded Probably f e l t over whole Earth. Extremely rare Infrequent 4 . 15 100 500 6 000 30 000 150 000 1 000 000 F e l t over large area of Earth. Extreme damage. Great damage. Serious. R a i l -way tracks bent. Widespread dam-age to b u i l d -ings. Moderate damage. F e l t by most people i n the area. F e l t by a few. Recorded by instruments. Recorded only by very s e n s i t i v e instruments. Seldom f e l t . ( a f t e r Janes 1976) 1 3 9 A second way of measuring the strength of an earthquake i s with the Modified M e r c a l l i Scale of Earthquake Intensity. This scale uses estimates of damage i n a p a r t i c u l a r area. The fa r t h e r away from the epicentre of an earthquake, the lower the i n t e n s i t y . An earthquake w i l l have only one Richter magnitude, but may have many M e r c a l l i i n t e n s i t i e s . The table below t e l l s you how to estimate the M e r c a l l i i n t e n s i t y of an earthquake i n your area. Modified M e r c a l l i Scale of Earthquake Intensity I. Not f e l t except by a very few under e s p e c i a l l y favourable circumstances. Birds and animals uneasy. D e l i c a t e l y suspended objects may swing. I I . P e l t only by a few persons at r e s t , e s p e c i a l l y on upper f l o o r s of b u i l d i n g s . I I I . F e l t noticeably indoors, e s p e c i a l l y on upper f l o o r s of buildings, but many people do not recognize i t as an earthquake. Parked cars may rock s l i g h t l y . Vibrations l i k e the passing of l i g h t trucks. Duration of shaking can be estimated. . IV. F e l t indoors by many, outdoors by a few. I f at night, some awakened. Dishes, windows, doors disturbed. Walls creak. Sensation l i k e the passing of heavy trucks. Parked cars rocked noticeably. V. F e l t by nearly everyone. Some dishes, windows etc. broken. A few instances of cracked p l a s t e r . Unstable objects overturned. Disturbances of trees, poles and other t a l l objects sometimes noticed. VI. F e l t by a l l . Many frightened and run outdoors. Some 140 heavy f u r n i t u r e moved. Books knocked o f f shelves, pictures off walls. A few instances of f a l l e n p l a s t e r or damaged chimneys. Otherwise, damage i s s l i g h t . VII. Everybody runs outdoors. D i f f i c u l t to stand up. Negligible damage i n buildings of good design and construction; s l i g h t to moderate i n we l l b u i l t structures; considerable i n poorly b u i l t or badly designed structures; some chimneys broken. Noticed by persons d r i v i n g cars. VIII. Damage s l i g h t i n s p e c i a l l y designed structures; p a r t i a l collapse i n ordinary b u i l d i n g s . Panel walls thrown out of frame structures. Chimneys, fac t o r y stacks, columns, monuments and walls f a l l . Heavy f u r n i t u r e overturned. Small amounts of sand and mud ejected from cracks i n the ground. IX. Damage considerable i n s p e c i a l l y designed structures, p a r t i a l collapse of su b s t a n t i a l b u i l d i n g s . Buildings s h i f t e d o f f foundations, ground cracked. Serious damage to r e s e r v o i r s and underground pipes. General panic. X. Some w e l l - b u i l t wooden structures destroyed; most masonry and frame structures destroyed. Ground badly cracked. R a i l s bent s l i g h t l y . Considerable l a n d s l i d e s from r i v e r banks and steep slopes. Water splashed over banks. XI. Few masonry structures remain standing. Bridges destroyed. Broad f i s s u r e s i n ground. Underground pipe-l i n e s out of ser v i c e . Earth slumps and l a n d s l i p s i n sof t ground. R a i l s bent severely. Figure 7 0 . Observed M e r c a l l i i n t e n s i t i e s from the South Okanagan earthquake of January 2 9 , 1 9 7 5 . ( A f t e r Wetmiller 1 9 7 7 ) 142' XII. Damage t o t a l . Waves seen on ground surfaces. Lines of sight and l e v e l d i s t o r t e d . Objects thrown upward into the a i r . "The ultimate catastrophe". (Woodrow 1 9 7 0 ) . In general, locations f a r t h e r away from the epicentre of the earthquake have lower M e r c a l l i i n t e n s i t i e s than those close to the epicentre. Look at Figure 7 0 which shows the e f f e c t of a mild earthquake i n the Okanagan V a l l e y of southern B r i t i s h Columbia. Notice how the i n t e n s i t i y i s lower at greater distances from the epicentre. The 1964 Alaska earthquake was one of the greatest to occur i n North America i n recent h i s t o r y . Figures 71 to 74 show some of the damage which r e s u l t e d . Compare, the damage to the two buildings shown i n Figure 71 • Notice how the concrete block structure has been badly damaged, while the wOod frame house next door i s untouched. This happened since wood i s much more f l e x i b l e than b r i c k . When wood buildings are shaken, they tend to bend a l i t t l e b i t before breaking. However, even a wood b u i l d i n g w i l l break i f the force i s great enough (Figure 7 2 ) . In the downtown area of the c i t y of Anchorage, a l a n d s l i p caused one side ' of Fourth Avenue to drop s t r a i g h t down about three metres. Figure 73 shows a l l the b u i l d i n g s on the right-hand side of the st r e e t are about three metres lower than those on the l e f t , with the crack running down the middle of the s t r e e t . A f t e r an earthquake, i t i s frequently d i f f i c u l t to bring help to the survivors, and t h i s was c e r t a i n l y the case i n Alaska. Most of the road and r a i l l i n k s were 143 F i g . 71 , Compare the damage to these two buildings during the 1964 Alaska earthquake. The apartment block was b u i l t with concrete f l o o r slabs and unreinforced block walls. The house next door was a wood frame structure. (Photograph courtesy of U.S. Geological Survey). F i g . 7 2 . Ground collapse demolished t h i s elementary school i n the c i t y of Anchorage during the 1964 Alaska earthquake. Fortunately, there were no people i n the school at the time. 144 F i g . 73 . A landslide during the earthquake caused the r i g h t side of t h i s s t r e e t i n Anchorage to drop three metres below the l e v e l of the o r i g i n a l l e v e l . (Photograph courtesy of U.S. Geological Survey). F i g . 74a. Railway l i n e s damaged by earth movement during the 1964 Alaska earthquake. (Photograph courtesy of U.S. Geological Survey). 145 cut (Figure 74a), which meant that most rescue workers had to t r a v e l there by sea or a i r . In our own country, the west coast of Canada i s the area where earthquakes occur most frequently. On the coast of B r i t i s h Columbia and the nearby ocean f l o o r there are an average of 3 0 0 earthquakes each year. In comparison, Alberta, Saskatchewan and Mamitoba together average only two earthquakes per year (Stevens 1 9 7 3 ) . Fortunately, most coastal earthquakes are too small to be f e l t , and can be recorded only by very s e n s i t i v e instruments. Large earth-quakes with a Richter magnitude over 6 . 5 occur about once every three years (Stevens 1 9 7 3 ) . Most of these are located i n the ocean f l o o r o f f our coast, and therefore cause no ':);:•: damage. I f any of these had occurred i n a major population centre, the damage would have been severe - probably b u i l d -ings damaged and people k i l l e d . Since 1912 when accurate record keeping began i n western Canada, there has been only one earthquake of magnitude 8 . 0 . Occurring i n 1949, i t was located near the Queen Charlotte Islands. Because the area was so l i g h t l y populated, very l i t t l e damage was reported. In 1946, an earthquake of magnitude 7 * 3 happened i n the S t r a i t of Georgia between Powell River and Courtenay. Many buildings i n the town of Courtenay were damaged, i n c l u d i n g the elementary school whose chimney collapsed through the roof. Fortunately, there were no i n j u r i e s . (Hodgson 1965). In Canada, the Earth Physics Branch 'of the f e d e r a l Ministry of Energy, Mines and Resources i s responsible f o r 145 the study of earthquakes. They operate a network of over t h i r t y earthquake observatories spread across the country. The observatory at A l e r t , on Ellesmere Island only 800 km from the north pole i s the most northerly s t a t i o n i n the world. The continuous records produced by these stations allow the s c i e n t i s t s to locate regions of possible earth-quake hazard. Both the B r i t i s h Columbia coast and the St. Lawrence Valley of Quebec are areas where the l i k e l i h o o d of major earthquake damage i s high. When l o c a t i n g a power plant i n Quebec, a dam i n B r i t i s h Columbia, or a p i p e l i n e i n the Yukon, a d e t a i l e d knowledge of the l o c a l earthquake r i s k i s e s s e n t i a l . The s c i e n t i s t s of the Earth Physics Branch have prepared an Earthquake Risk Map (Figure 74b), as a guide f o r engineers, and can on request provide the very l a t e s t f i g u r e s on earthquake hazard f o r any point i n Canada. Questions 1. Explain the d i f f e r e n c e between the focus and the epicentre of an earthquake. 2. Explain why an earthquake has only one Richter magnitude, but many M e r c a l l i i n t e n s i t i e s . • 3. Estimate the M e r c a l l i i n t e n s i t i e s of the 1964 Alaska earthquake at the l o c a t i o n s shown i n Figures 71 and 72:. 5. In which earthquake hazard zone, would you f i n d each of the following Canadian c i t i e s : Vancouver, Prince Rupert, Calgary, Winnipeg, Toronto, Ottawa, Quebec C i t y , H a l i f a x , and St. John's. 147 ^RTHQUAKS HAZARD ZONES 0 No damage 1 Minor damage 2 Moderate damage 3 Major damage Figure74b. This map shows the chances of an earthquake i n various parts of Canada. In which zOne do you l i v e ? (Energy, Mines & Resources - Canada: "New Seismic Zoning Map, 1970) 148 INVESTIGATION 21 Reading Seisinograms At 2:48 a.m. P a c i f i c Standard Time on November 3 0 , 1 9 7 5 , while most people i n B r i t i s h Columbia were asleep, southern Vancouver Island and the lower Fraser Valley were shaken by an earthquake. Wooden buildings creaked and groaned, dishes on shelves r a t t l e d , and a few people were Figure 74c. Using a c o i l spring to demonstrate a P-wave. 149 awakened from t h e i r sleep. The earthquake was a mild one, r e g i s t e r i n g 4.9 on the Richter magnitude scale. I t caused no serious damage. At V i c t o r i a , Port Alberni and Haney, the seismic recording stations made a record of t h i s earthquake on t h e i r graphs. In t h i s exercise you w i l l l e a r n how to read these graphs, c a l l e d seismograms, and how to f i n d the precise l o c a t i o n of an earthquake. Purpose: to read seismograms, and use them to locate an earthquake. Procedure Part 1 P and S Waves A. Stretch a c o i l e d spring or s l i n k y out on the classroom f l o o r . Have your partner hold one end of the spring i n a f i x e d p o s i t i o n . Gather a number of c o i l s of the spring at one end to form a compressed section (Figure 74c). Release the compressed section while s t i l l holding the end of the spring. In which d i r e c t i o n does the compression tra v e l ? In which d i r e c t i o n s does each i n d i v i d u a l c o i l of the spring move? How does each c o i l cause the next c o i l to move? B. The wave you have just made i s an example of a P-wave. The l e t t e r P stands f o r eithe r Primary or Push. In s o l i d rock, t h i s type of wave occurs when an earthquake causes one rock p a r t i c l e to push on the next p a r t i c l e , which pushes the next, and so on. Immediately, the f i r s t p a r t i c l e rebounds to i t s o r i g i n a l p o s i t i o n , then the next p a r t i c l e , and so on. Write the term P-wave and i t s d e s c r i p t i o n i n your notebook. C. Stretch the spring on the f l o o r and have your partner hold one end steady. Jerk your end sideways to produce a TIME \ n_ « n n B—«—n—»—n—«—«—"—n—"—n—*—*—*——*-VICTORIA PORT ALB E RN! HANEY 02h48m33s " V V 1/ » I T If K IC V I T V » II * « I f " - V II 1 B lr K U If F i g . .76. Seismograms of the November 30, 1975 earthquake.(Courtesy of W. Milne, -v V — \ l — I I — I I — I f 1 5 1 s t a r t of P-wave• Figure 77 • Example of a P-wave a seismogram. s t a r t of s t a r t of Figure 78-. Example of a P-wave an S-wave on a seismogram. 1 5 2 ' wave (Figure 7 5 ) . In which d i r e c t i o n does the wave travel? In which d i r e c t i o n s does each i n d i v i d u a l c o i l of the spring move? How does each c o i l cause the next c o i l to move? D. The wave .you have just made i s an example of an S-wave. S stands f o r eith e r Secondary or Shake. In s o l i d rock, t h i s type of wave occurs when an earthquake causes one rock p a r t i c l e to drag the next p a r t i c l e sideways, which drags the next, and so on. After the wave passes, each p a r t i c l e rebounds to i t s o r i g i n a l p o s i t i o n . Write the term S-wave and i t s d e s c r i p t i o n i n your notebook. E. Stretch two i d e n t i c a l 3 cm diameter c o i l e d springs on the f l o o r . At the same time, s t a r t a P-wave i n one spring and an S-wave i n the other. Which wave t r a v e l s faster? Which wave ar r i v e s at the other end of the spring f i r s t ? Part 2 Reading a Seismogram F. Figure 7 6 shows the seismic records of the November 3 0 , 1 9 7 5 earthquake, made at three d i f f e r e n t l o c a t i o n s . The top and bottom traces are time markings, where each mark ind i c a t e s one second. How many seconds long i s the ent i r e trace? G . When no earthquakes are being recorded, the seismometer records a nearly s t r a i g h t l i n e . Movement caused by earth-quake waves i s recorded by upward and downward movements of the l i n e s . The f a r t h e r the movement, the stronger the waves. At which s t a t i o n were the strongest waves recorded? At what time were the strongest waves recorded at t h i s s t a t i o n , (estimate to the nearest 0 . 1 seconds)? H. Copy the data table below in t o your notebook. 153 Station P-wave a r r i v a l time S-wave a r r i v a l time Travel time di f f e r e n c e Distance to earthquake V i c t o r i a Port Alberni Haney I. The P-^Waves, which t r a v e l f a s t e s t , are the f i r s t to a r r i v e at a recording s t a t i o n . They are shown by a sudden change i n the d i r e c t i o n of the l i n e (Figure 7 7 ) . From Figure 76 . , read the a r r i v a l times of the P -waves at each s t a t i o n . Estimate these to the nearest 0.1 seconds, and record them i n your data t a b l e . J . The S-waves, which t r a v e l more slowly, a r r i v e next at the recording s t a t i o n . They are shown by a sudden increase i n the movement of the l i n e (Figure 78 ). From Figure 76-, read the a r r i v a l times of the S-waves to the nearest 0.1 seconds and record these i n your data t a b l e . K. I f you were standing r i g h t at the focus of an earth-quake, the P and S waves would a r r i v e together. The f a r t h e r away you are from the focus, the greater the diff e r e n c e i n t h e i r a r r i v a l times. You w i l l use t h i s d i f f e r e n c e to f i n d the distance from each s t a t i o n to the earthquake. Subtract the P and S wave a r r i v a l times to f i n d the t r a v e l time difference at each s t a t i o n . Record these d i f f e r e n c e s i n your data ta b l e . L. The graph i n Figure 79 r e l a t e s the t r a v e l time d i f f e r e n c e to the distance from the epicentre of the earthquake. For example, i f . the t r a v e l time d i f f e r e n c e i s 15 seconds, look 1.55. 0 100 km » « * * • • Seismograph l o c a t i o n s : x Figure 80. Earthquake recording s t a t i o n s i n southwestern B r i t i s h Columbia. 156 f o r the place where the l i n e s are 15 seconds apart, then read the corresponding distance from the v e r t i c a l axis, which i s 131.km. In other words, i f the t r a v e l time difference i s 15 seconds, the epicentre i s 131 km away. Use Figure 79 to f i n d the distance to the epicentre from each recording s t a t i o n . Write these distances i n your data t a b l e . ' M. Your teacher w i l l supply you with a copy of the map i n Figure 80 . Set your compass at the scale distance to the earthquake from V i c t o r i a . Draw a c i r c l e on the map, using the V i c t o r i a s t a t i o n as a centre. Can a singl e s t a t i o n t e l l the distance to an earthquake? Can a single s t a t i o n t e l l the d i r e c t i o n to an earthquake? Can a single s t a t i o n f i n d the exact l o c a t i o n of an earthquake? N. Repeat Procedure M using the data from Port A l b e r n i . Can two stations f i n d the d i r e c t i o n to an earthquake? Can two sta t i o n s f i n d the exact l o c a t i o n of an earthquake? 0 . Repeat Procedure M using the data from Haney. What i s the l e a s t number.of stations required to locate an earth-quake? Where was the epicentre of the earthquake of November 3 0 , 1 9 7 5 located? Put an X on your map at t h i s point. (Note: i f your c i r c l e s do not cross at a single point, choose a l o c a t i o n as close as possible to t h e i r crossing p o i n t s ) . Questions 1 . Which would probably cause more damage and i n j u r y : a) an earthquake i n Vancouver or one at Williams Lake? b) an earthquake at 2 : 0 0 p.m. Tuesday, or one at 1:57. 7:00 a.m. Sunday? 2. Explain how the amount of destruction caused by a severe earthquake depends on i t time and l o c a t i o n . 3. From the following data, p l o t on a map the approximate p o s i t i o n of the earthquake of February 10, 1977* Station P-wave S-wave a r r i v a l time a r r i v a l time Port Alberni 04h 49m 29.1s 04h 49m 41.9s V i c t o r i a 04h 49m 32.6s 04h 49m 49.3s Pender Island 04h 49m 36.0s 04h 49m 52.8s Haney 04h 49m 45.0s 04h 50m 12.0s 4. Locate the approximate p o s i t i o n of the epicentre of the earthquake of rAugust 3, 1976. Station P-wave S-wave a r r i v a l time a r r i v a l time Haney 07h 56m 13.0s 07h 56m 17.4s V i c t o r i a 07b. 56m 15-8s 07h 56m 25-5s Port Alberni 07b 56m 29.8s 07b 56m 51.9s ( A l l earthquake data provided by courtesy of W. Milne, P a c i f i c Geoscience Centre). Conclusion What have you learned about seismograms and earthquake NARRATIVE 23 Tsunami When i s a t i d a l wave not a t i d a l wave? When i t i s a tsunami. A tsunami (the word i s Japanese) i s an ocean wave caused by an earthquake, and i t has nothing to do with the 158 t i d e s . When an earthquake causes a sudden u p l i f t or drop i n the ocean f l o o r , the movement of the water can cause a wave to s t a r t . In the open ocean, a tsunami t r a v e l s very quickly, about 740 kilometres per hour. However, since i t s crest i s only a few centimetres high, and there i s about 160 km between crests, the tsunami i s hardly even noticeable. Only when a tsunami approaches a shore does i t become dangerous. The shallow water causes the wave to slow down to perhaps 50 km per hour, and the height of the crest to r i s e up to 20 or 30 metres. (Press, Siever 1978). Can you imagine a shoreline being h i t by a 30 metre wave t r a v e l l i n g at 5 0 km per hour? Figures 81 and 82 show some of the r e s u l t s of the tsunami which followed the 1964 Alaska earthquake. In 1883, the explosion of the volcano Krakatoa i n Indonesia caused a tsunami which drowned an estimated 36 000 people. In the Sanriku area of Japan, which has been h i t by many tsunamis', 27 000 people died i n 1896, and several thousand more i n 1 9 3 3 * Tsunamis can a f f e c t any of the P a c i f i c Islands, and a l l countries on the P a c i f i c Rim. Hawaii, located near the centre of the ocean, has been h i t by 32 tsunamis i n t h i s century. In 1946, and again i n 1960, many people drowned and m i l l i o n s of d o l l a r s damage was done i n the c i t y of H i l o . (MacDonald, Abbott 1970). During the night of March 28, 1964, B r i t i s h Columbia was h i t by a tsunami caused by the great Alaska earthquake. From up and down the coast, reports of damage came i n from 1 5 9 F i g . 81. Waves at Whittier, Alaska, drove t h i s piece of timber through the truck t i r e during the 1964-earthquake. (Photograph courtesy of U.S. Geological Survey). F i g . 82 . The tsunami which struck the town of Kodiak Alaska a f t e r the 1964- earthquake, caused t h i s damage. 160 towns and v i l l a g e s : B u l l Harbour - wave 17 feet high; . Winter Harbour - o i l company dock ripped out to sea; Port McNeill - four m i l l i o n board feet of lumber d r i f t i n g a f t e r booms smashed by waves; Port A l i c e - twenty c r a f t washed away from moorings.; Hot Springs Cove. - f i v e houses demolished by f i r s t waves, eleven others l a t e r l i f t e d bodily o f f t h e i r foundations and deposited 300 f e e t away; Spring gove -34 foot t r o l l e r sunk; S a r i t a I n l e t - Bamfield l i f e b o a t evacuates community; Amiah I n l e t - search and rescue p a r t i e s pick up a l l inhabitants a f t e r a l l houses damaged by waves; Holberg Bay - trees with f i v e foot butts snapped o f f and c a r r i e d a mile inland; San Jose Bay - waves 2 5 feet high. In a l l , damage from the 1964 Tsunami was f a i r l y l i g h t since most of our coast i s uninhabited. (Vancouver Sun, 1964) In the tv/In c i t i e s of A l b e r n i and Port A l b e r n i however, the s i t u a t i o n was much more serious. Eyewitness reports t e l l the story: "People screamed and began running towards me - the second wave was i n the s t r e e t s . I t covered cars, crashed into stores and buildings, and toppled a power l i n e . Then I was running to escape too." "I was- amazed to see two b i g houses - 30 feet by 50 feet and two f l o o r s high - f l o a t i n g out i n the Somass River. They gradually broke, up and sank." "Then I saw men running as the second wave came up and into the s t r e e t . When the wave r o l l e d down the main s t r e e t i t covered cars and trucks and h i t b u i l d i n g s . I got separated from my dad. I think he got into h i s car with some others, I got into a car too, and got to high ground." In a l l , 300 houses were destroyed i n Alberni and Port A l b e r n i . Miraculously, 161 no-one was. k i l l e d . (Vancouver Sun, 1964). In order to save l i v e s from future tsunamis, the countries around the P a c i f i c rim have co-operated to form the International Tsunami Warning System. As soon as a tsunami i s detected, s c i e n t i s t s immediately calculate i t s speed and d i r e c t i o n . Warnings are then sent out to threatened areas, t e l l i n g inhabitants to leave the shore and move to higher ground. Although nothing can be done to prevent damage to buildings and property, at l e a s t the people can be saved. There w i l l always be tsunamis i n the P a c i f i c Ocean, but i n t e r n a t i o n a l co-operation w i l l reduce t h e i r danger to j peoples l i v e s . (Janes 1976). Questions 1. What v/ould be the e f f e c t of a tsunami on: a) a ship i n the middle of the P a c i f i c Ocean? b) a boat moored i n a shallow harbour? 2. You have j u s t received a tsunami warning, and you have t h i r t y minutes i n which to leave your home and s t a r t moving to higher ground. L i s t the things you w i l l take with you i f : a) you have to walk or run. b) you are able to d r i v e . Plate Tectonics The Earth i s a dynamic planet. As the m i l l e n i a pass, the geography of the Earth changes. Continents c o l l i d e and separate, oceans open and close, mountains are thrust up and eroded away. Any understanding of the Earth and i t s 162 development must therefore include a knowledge of the reason, f o r these changes - plate movement. B r i t i s h Columbia i s located on the boundary between two major, plates, the P a c i f i c plate and the North American pl a t e . Between these two are a number of minor pla t e s . The movement of these plates i s responsible f o r much of the landscape of t h i s province. I t therefore follows that i n order to understand the o r i g i n s of l o c a l landforms, the student must have a knowledge of plate t e c t o n i c s . Much of the i n i t i a l evidence f o r plate movement was garnered from studies of the ocean f l o o r s . This section of the proposed curriculum begins by introducing the student to the shape of the f l o o r of the A t l a n t i c Ocean (Investigation 24, Addendum), emphasizing the mid-Atlantic ridge and i t s c e n t r a l r i f t system..This i s followed by a d e s c r i p t i o n (Narrative 2 5 , below) of the theory of continental d r i f t as proposed by A l f r e d Wegener, and the evidence he used to support i t . Although a number of texts (e.g. Ramsey 1 9 7 8 ) include material on plate t e c t o n i c s , none of those consulted show the evolution of the.theory from Wegener's o r i g i n a l hypothesis. This recounting of the development of the theory i s unique to t h i s proposed curriculum, intended to show the student that s c i e n t i f i c theories are not immutable, but do change over time as new information becomes a v a i l a b l e . The following three exercises, (Investigations 26 and. 2 7 , Narrative 28, Addendum), present evidence f o r plate movement - such as the jigsaw f i t of the continents bordering on the A t l a n t i c Ocean, the age and magnetic s t r i p i n g of the 163' sea f l o o r along the oceanic ridges, and the symmetry of polar wandering curves. Narrative 29 (below) continues the development of plate tectonic theory started i n Narrative 25, showing how Wegener's theory developed into i t s present form. Once the students have become f a m i l i a r with the concept of moving plates, they are introduced to the types of c o l l i s i o n which can take place along plate boundaries (Investigation 30, Addendum). Many students have heard of the San Andreas f a u l t , and w i l l tend to ask questions about i t at t h i s point i n the curriculum. To aid teachers i n answering these, and to provide the student with f a c t u a l information about the f a u l t , Narrative 31 (below) presents a d e t a i l e d d e s c r i p t i o n and photographs. Although the d e t a i l given i s much greater than that found i n other junior high school texts (e.g. Jackson & Evans 1973), i t has been found to be quite understandable by students of t h i s age. The unit on plate tectonics concludes with another feature unique to t h i s proposed curriculum, a d e s c r i p t i o n of the e f f e c t s of plate movement along the coast of B r i t i s h Columbia. This d e s c r i p t i o n (Narrative 32, below), was compiled from academic p u b l i c a t i o n s of the l a s t ten years, and presents information which would be very d i f f i c u l t f o r many junior high school students and teachers to locate. As noted i n other parts of t h i s proposed curriculum, i t i s f e l t that descriptions and examples of l o c a l features are of more i n t e r e s t to the student than information about dis t a n t areas. The following pages include the student exercises r e f e r r e d to above. The remainder may be found.in the Addendum. 164 NARRATIVE 25 The Moving Continents . Look at a map .of the A t l a n t i c Ocean (Figure 85). Can you see how the continents on ei t h e r side of the ocean could be f i t t e d together l i k e a crude jigsaw puzzle? As early as 1620, Francis Bacon an Engl i s h s c i e n t i s t , commented on t h i s i n one of h i s books. During the next two centuries, other people t r i e d to invent theories to account f o r t h i s strange correspondence i n the shapes of the c o a s t l i n e s . Some people thought that the A t l a n t i c was a huge r i v e r v a l l e y whose sides had become separated during Noah's Flood. Others believed i n a mythical continent that they c a l l e d " A t l a n t i s " , and that i t had sunk beneath the waters to form the A t l a n t i c Ocean. A few s c i e n t i s t s proposed the theory of continental d r i f t . This theory states that the continents were once part of a single land mass - a "supercontinent" -which broke apart many m i l l i o n s of years ago. Since the breakup, the continents have slowly moved across the globe to occupy t h e i r present p o s i t i o n s . In t h i s century, the f i r s t man to present evidence to support the theory of continental d r i f t was a German meteorologist named A l f r e d Wegener. He believed that since rocks could be pushed up v e r t i c a l l y to form mountains, they could also move sideways. To support the theory, Wegener studied not only the shapes of the continents, but also the rocks of which they are made, and the f o s s i l s preserved i n these rocks. He found a s t r i k i n g s i m i l a r i t y i n the rocks and f o s s i l s on opposite sides of the A t l a n t i c . T 6 5 One of the f o s s i l s studied by Wegener was Mesosaurus, a small r e p t i l e that l i v e d l a t e i n the Paleozoic Era, about 270 m i l l i o n years ago. This f o s s i l was found i n B r a z i l and i n South A f r i c a , but nowhere el s e . Wegener argued that i t was u n l i k e l y that B r a z i l and South A f r i c a had ever been joined by a land bridge so Mesosaurus could walk across. He also believed that the r e p t i l e could not swim well enough to cross an ocean. The only remaining p o s s i b i l i t y was that South America and A f r i c a had once been part of the same continent, and that t h i s continent had s p l i t and the halves had d r i f t e d apart (Hallam 1972). Wegener also noted that large blocks of p a r t i c u l a r l y ancient rock occur both i n A f r i c a and South America. I f the continents are brought together, the blocks l i n e up p r e c i s e l y . Wegener compared t h i s to matching up l i n e s of p r i n t on pieces of torn newspaper, then concluding that the pieces had once been part of a single sheet. (Hallam 1975). . As might be expected, Wegener sketched a map of how he thought the world looked before the supercontinent broke apart. This sketch i s shown i n Figure 84 . Was A l f r e d Wegener r i g h t or wrong? In the next few exercises, you w i l l look at some of the evidence. Questions 1. What pieces of evidence would have to be discovered i n order to prove that A t l a n t i s , complete with people and c i t i e s , had sunk beneath the ocean? 166 Figure 84- . A l f r e d Wegener's idea of what the world looked l i k e before the continents d r i f t e d apart. ( A f t e r Hallam 1 9 7 5 ) . 16?; NARHATIVE 29 Plate Tectonics and Continental D r i f t .-Since A l f r e d Wegener's time, the theory of continental d r i f t has changed, considerably as new f a c t s have been discovered. Even the name of the theory has changed from "continental d r i f t " to "plate t e c t o n i c s " . Wegener used the term continental d r i f t because he thought that only the continents moved. He believed that the lower parts of the Earth's crust acted l i k e a very s t i f f f l u i d through which the continents slowly d r i f t e d , pushed by forces r e l a t e d to 168 the r o t a t i o n of the Earth (Figure 8 5 ) . In the modern theory, we believe that large r i g i d sections of the Earth's crust, c a l l e d p l a t e s , move over the upper mantle or asthenosphere. The continents are c a r r i e d as "passengers" on these plat e s (Figure 8 6 ) . Movement i s caused when hot material pushing up from below forms new ocean f l o o r and pushes the plates apart. This occurs along the midocean ridges such as the Mid-Atlantic Ridge. Where two plates c o l l i d e , one i s subducted or pushed under the other. Eventually the subducted plate reaches the asthenosphere where i t probably melts. Where subduction occurs, the ocean f l o o r i s pushed down to form a deep ocean trench. The maps shown i n Figures 8? and .88 allow you to compare two views of Pangea (the name f o r the supercontinent) before i t broke up. The most noticeable d i f f e r e n c e between Wegener's view and our modern view i s i n the p o s i t i o n of India. We now believe that India broke away from southern A f r i c a , then d r i f t e d towards A s i a . Eventually, India . c o l l i d e d with Asia, where i t remains today. Our view of the present day world i s shown i n Figure 89 • The crust consists of s i x major p l a t e s and a number of minor p l a t e s . Arrows show the d i r e c t i o n s i n which the plates are moving. Plates are being pushed apart along the midocean ridges, and being subducted along the deep ocean trenches. New ocean f l o o r i s constantly being created, and old ocean f l o o r i s being destroyed. The theory of plate t e c t o n i c s explains a number of 169. Figure 8 5 - A l f r e d Wegener's model of continental d r i f t . The continents moved through the crust of the Earth, pushed by forces caused by the r o t a t i o n of the Earth. This theory has now been modified into the present theory of plate t e c t o n i c s . ( A f t e r Hallam 1 9 7 5 ) . Figure 8 6 - . Plate tectonics theory has the continents r i d i n g as "passengers" on r i g i d plates which move over the asthenosphere. The plates are pushed apart by new hot material r i s i n g from the asthenosphere to form new sea f l o o r . ( A f t e r Hallam 1 9 7 5 ) . 170 N O R T H AMEP- ICA A S I A AFRICA SOUTH A M E R I C A '•NOIA V A O S T R A C I / t l T A A C T I C A Figure 87 . A l f r e d Wegener's idea of how the world appeared 200 m i l l i o n years ago, before Pangea broke apart. ( A f t e r Hallam 1975)• NORTH A f £ R i C A A F R I C A ASIA S O U T H A M E R I C A Figure 88. Modern idea of how the world appeared 200 m i l l i o n years ago. Notice the postion of. India. ( A f t e r Hallam 1975). •/Philippine V P l a l j e / P a c i f i c Plate 0| "r ndfrttn- A u s t r s K l i a m > * , A n t a r c t i c Plate Figure 89 . This map shov/s the major plates of the Earth's crust. 1 7 2 . 0 Figure 90 . In t h i s photograph taken by a Landsat s a t e l l i t e , you can see the p l a i n of India, and the Himalaya Mountains. The Himalayas were pushed up when the plate carrying India c o l l i d e d with the Asian p l a t e . 173" observations which have puzzled earth s c i e n t i s t s f o r many years, such as earthquakes, volcanoes and mountain b u i l d i n g . Compare the map i n Figure 89 with the maps of volcano and earthquake locations that you made i n Investigations 15 and 2 3 . Notice how the earthquakes and volcanoes seem to occur along the boundaries between p l a t e s . Earthquakes happen where plates c o l l i d e or s l i d e past each other. Volcanoes are found where the f r i c t i o n a l heat caused by s l i d i n g plates can melt rock. Mountain ranges are formed where continents are "crumpled" as plates c o l l i d e . For example the Himalaya Mountains, highest i n the world, were formed where India c o l l i d e d with A s i a . Figure 90. shows .a s a t e l l i t e photograph of one of the places where t h i s c o l l i s i o n occurred. Imagine the force ;needed to push up mountains to a height of over 8000 metres! Other land features which you may study i n the future, such as i s l a n d arcs, r i f t v a l l e y s and mineral deposits may also be explained by the theory of plate t e c t o n i c s . Earth s c i e n t i s t s are now i n v e s t i g a t i n g the p o s s i b i l i t y that plate movement has been going on f o r the e n t i r e h i s t o r y of the Earth. I t i s possible that before Pangea existed, the continents were moving separately. They may have c o l l i d e d to form Pangea, and are now separating again. W i l l the continents a l l come together again as a single land mass at some time i n the f a r d i s t a n t future? We now know that the map of the world does not remain the same f o r a l l time. Each year i t changes by a few centimetres, every m i l l i o n years by a few kilometres. What w i l l the world look 174-l i k e , one hundred m i l l i o n years from today? (Press, Siever 1 9 7 8 ) . Questions 1 . Examine Figure 8 9 and l i s t the names of the s i x largest plates. 2 . Use you a t l a s to f i n d the name of the ocean ridge where the Nazca plate i s separating from the P a c i f i c p l a t e . 3. Name the deep ocean trench where the P a c i f i c plate i s being subducted beneath the P h i l i p p i n e p l a t e . 4- . Use plate tectonics to explain why many volcanoes are found i n Iceland. 5 - Which two plates were responsible f o r the 1 9 7 8 earth-quake i n Iran which k i l l e d about 2 5 0 0 0 people? 6 . In Investigation 2 2 you p l o t t e d the p o s i t i o n of the Queen Charlotte F a u l t . Between which two p l a t e s i s t h i s f a u l t a boundary? NARRATIVE 31 The San Andreas F a u l t On A p r i l 18, 1 9 0 6 , the c i t y of San Francisco was shattered by a great earthquake. I t had a Richter magnitude of 8 . 3 , and a maximum M e r c a l i i i n t e n s i t y of IX. As a r e s u l t , nearly 7 0 0 people l o s t t h e i r l i v e s , and the c i t y suffered many m i l l i o n s of d o l l a r s of damage. This d i s a s t e r was a r e s u l t of earth movement along the San Andreas F a u l t , a great crack i n the Earth's crust where the P a c i f i c plate 175 i s slowly moving past the American plate (Figure 91 ). The San Andreas Fault i s one of the most studied geological features on the Earth. In d e t a i l , i t i s a complex zone of crushed and broken rock about 1000 km long, up to 2 km wide, extending down into the Earth's crust f o r at l e a s t 30 km. I t stretches f o r most of the length of C a l i f o r n i a (Figure 92). Examination of almost any excavation i n the f a u l t zone shows thousands of small f r a c t u r e s , pulverized rock, and few pieces of s o l i d rock. From the a i r , the f a u l t appears as a s t r a i g h t l i n e arrangement of ridges, lakes, bays and v a l l e y s . On the ground, the f a u l t zone can be recognized by long, low, s t r a i g h t c l i f f s and narrow ridges. I t shows up most c l e a r l y on the dry grass-land of the Carrizo P l a i n i n southern C a l i f o r n i a (Figure 93 ). Precise measurement along the f a u l t shows that i t s western side i s moving northward at a rate of approximately 5 cm per year. Of course, t h i s does not mean that 5 cm of movement occurs every year. For a number of years, the Earth's crust "takes up the s t r a i n " by slowly bending. When a c e r t a i n l i m i t i s reached, the rock suddenly breaks and snaps to a new p o s i t i o n . I t i s t h i s sudden snap which we f e e l as an earthquake. During the 1906 earthquake, some parts of the ground on the western side of the f a u l t moved northward by as much as seven metres! In t o t a l , over the l a s t 100 m i l l i o n years, geologists believe that the t o t a l amount of movement has amounted to over 500 km. . Before people r e a l i z e d that the San Andreas Fault was there, hundreds of thousands had moved to C a l i f o r n i a . Since 1 7 6 San Andreas Fault P a c i f i c Plate American Plate Figure 91 • The San Andreas Fault i s the boundary where the P a c i f i c plate moves past the American p l a t e . Figure ^2 . Location of the San Andreas Fault i n C a l i f o r n i a . 1 7 7 Figure 9 3 . The l i n e of low ridges and g u l l i e s marks the trace of the San Andreas Fault across the C a r r i z P l a i n i n C a l i f o r n i a . (Photograph by J.R. Balsley, U.S. Geological Survey). 178 Figure 9 4 . . In t h i s photograph taken by a Landsat s a t e l l i t e you can see the traces of two great f a u l t s i n C a l i f o r n i a . The San Andreas Fault passes within 40 kilometres of the o u t s k i r t s of Los Angeles. 179 Figure 95 . Fault l o c a t i o n s i n the San Francisco area. ( A f t e r U.S.G.S. 1969) 180 then, m i l l i o n s more have b u i i t two great c i t i e s i n the v i c i n i t y of the f a u l t . Figure 9 4 i s a s a t e l l i t e photograph of Los Angeles, showing i t s l o c a t i o n only 7 0 km from the San Andreas Fa u l t . Figure 9 5 shows -how the f a u l t passes r i g h t through the o u t s k i r t s of San Francisco. A major earthquake could demolish e i t h e r of these c i t i e s . -No-one yet knows how to pre d i c t exactly when the next earthquake w i l l occur along the San Andreas F a u l t . Great earthquakes seem to happen only once or twice i n a century. Smaller earthquakes, recorded only by se n s i t i v e seismographs, occur almost every day. San Francisco was destroyed i n 1 9 0 6 . Since then, i t has been b u i l t i n exactly the same l o c a t i o n . A few geologists nov; c a l l San Francisco "the c i t y which waits to d i e " . (Anderson 1 9 7 1 , U. S. Geological Survey 1 9 6 9 ) . Questions 1 . Suppose that geologists have determined that there i s a 7 5 $ chance of a major earthquake occurring i n San Francisco within two days. a) What problems would a r i s e i n arranging an orderly evacuation? v b) What problems would a r i s e i f an evacuation was ordered, and tbe earthquake d i d not happen? c) What- problems would a r i s e i f an evacuation was not ordered, and the earthquake happened? d) How would you deal with people who refused to obey an evacuation order? 181 NARRATIVE 32 Plate Tectonics of B r i t i s h Columbia Geologically, B r i t i s h Columbia i s a very complicated place. To describe how the area developed, plate tectonics theory must answer a number of questions: 1 ) How have the mountains been formed? 2) Why are there volcanoes along the coast? Why are the Cascade volcanoes (e.g. Mount Baker) ac t i v e , while the G a r i b a l d i volcanoes are inactive? 3) What causes coastal earthquakes? 4-) Where i s the boundary between the P a c i f i c plate and the American plate? At present, we have no d e f i n i t e answers to these questions. Current theory does however, provide a good s t a r t towards the explanation of these features. Off the north coast of B r i t i s h Columbia, just west of the Queen Charlotte Islands, the P a c i f i c plate appears to meet the American plate at a.single boundary. This boundary i s the Queen Charlotte f a u l t , whose p o s i t i o n you p l o t t e d i n Investigation 22. Along t h i s f a u l t , the P a c i f i c plate i s s l i d i n g to the northwest, s i m i l a r to the movement along the San Andreas f a u l t i n C a l i f o r n i a . Canada's strongest recorded earthquake which had a Richter magnitude of 8.0, was caused by movement of the Queen Charlotte f a u l t i n 194-9. (Milne 1 9 7 6 ) . At f i r s t , s c i e n t i s t s thought that our mountains were simply caused by pressure between the American plate and the P a c i f i c p l a t e . However, the r e a l s i t u a t i o n appears to be 182 much les s simple. As the P a c i f i c plate moved northwards i n the past, i t brought blocks of land from the south up towards B r i t i s h Columbia. When these blocks c o l l i d e d with the American pla t e , they were "welded" on to the coast, where they have remained. The force of these c o l l i s i o n s apparently resulted i n a number of our mountain ranges. The l a s t of these blocks of land, a r r i v i n g about 140 m i l l i o n years ago, included Vancouver Island. Following t h i s c o l l i s i o n , pressure from below forced up the Coast Mountains. (B.C. Ministry of Education 1978). Plate movement near southern B r i t i s h Columbia i s not as easy to explain as that along the Queen Charlotte f a u l t . West of Vancouver Island, instead of a single f a u l t , there i s a complex system of ridges and f a u l t s . Figure 96 shows a s i m p l i f i e d diagram of these features. Magnetic studies of the seafloor on both sides of the Explorer and Juan de Fuca ridges show that spreading i s taking place. Volcanism brings up new rock from the asthenosphere, and new seafloor i s created as the sides of the ridges spread apart. This means then, that here the P a c i f i c plate does not meet the American plate d i r e c t l y . Between them, there are two minor plates named the Explorer plate and the Juan de Fuca p l a t e . The l o c a t i o n of the boundary between these two p l a t e s i s not c l e a r . (Riddihough, Hyndman 1976). As the Explorer and Juan de Fuca plates move eastwards, they are pushed under the American plate along the l i n e of the continental slope (Figure 9 7 ). As they are pushed downwards, the motion of the rock causes the 3 0 0 or so 183 earthquakes recorded each year along our coast. Eventually, when-the plates are pushed deep enough, they become hot enough to melt. Some of the molten rock f i n d s i t s way to the surface, r e s u l t i n g i n the coastal volcanoes. Measurements show that the Juan de Fuca plate i s moving from 2 to 3 centimetres per year, while the Explorer plate i s moving at only half t h i s speed.. Some s c i e n t i s t s have suggested that t h i s speed difference may explain why the Cascade volcanoes are s t i l l a c t i v e , while the G a r i b a l d i volcanoes are not (Riddihough 1978). The theory outlined above only begins to explain what i s happening along our coast. Many more years of study w i l l be required before earth s c i e n t i s t s have a complete understanding of plate t e c t o n i c s i n B r i t i s h Columbia. Questions 1. How could a block of land brought i n by the P a c i f i c plate- cause mountains to be b u i l t i n B r i t i s h Columbia? 2. a) Which would produce more magma, a plate being subducted r a p i d l y , or one subducting slowly? b) How does a speed diff e r e n c e between the Explorer and Juan de Fuca plat e s account f o r the dif f e r e n c e i n a c t i v i t y between the Cascade and the G a r i b a l d i volcanoes? 184-Figure 97 • Plate movement near the B r i t i s h Columbia Coast. 185 Earth Resources The f i n a l unit d f t h i s proposed curriculum concentrates on the mineral resources of the Earth, with an enphasis on the economic minerals of B r i t i s h Columbia. The section opens (Narrative 33, below) with an h i s t o r i c a l sketch of mining i n B r i t i s h Columbia, followed by a d e s c r i p t i o n of the present industry. Included i s some information on the l o c a t i o n and e x p l o i t a t i o n of f o s s i l f u e l deposits. Like many other sections of the proposed curriculum, t h i s u n i t continues the B r i t i s h Columbia regional emphasis, and presents information unavailable i n other junior high " school c u r r i c u l a . The section continues with an exercise on i d e n t i f i c a t i o n of minerals ( I n v e s t i g a t i o n 34, Addendum), concentrating upon those with economic importance. The Conclusion (Narrative 35, Addendum), i s i n the form of a shOrt summarizing note expressing a hope f o r the future. The student exercise r e f e r r e d to above may be found on the following pages. The remaining exercise may be r e f e r r e d to' i n the Addendum. 186 NARRATIVE 53 Earth Resources i n B r i t i s h Columbia -Modern society could not e x i s t without resources taken from the earth. Metals, coal, o i l , natural gas, cement, gravel - a l l these are extracted from the earth to support our way of l i f e . Without them, food and water supply, shel t e r , clothing, medicine, transportation and communication would be reduced to the pr i m i t i v e l e v e l of 10 000 years ago. Coal was the f i r s t material to be mined i n B r i t i s h Columbia, as part of the business of the Hudson's Bay Company on Vancouver Island during the days of the coastal f u r trade (Akrigg 1975)- These operations however, had l i t t l e e f f e c t upon the province. Mining became an important part of the economy i n 1858 with the f i r s t gold rush. The impact of the gold seekers i s hard to imagine. In January of 1858, V i c t o r i a was a small c o l o n i a l outpost with only 300 white inhabitants. By December of that year, 30 000 miners had passed through on t h e i r way to the gold f i e l d s , and V i c t o r i a now had 3000 permanent residents (Akrigg 1977). As the nineteenth century ended and the twentieth century began, attention turned from gold and s i l v e r to lead, zinc and copper. Over the next f o r t y years, the extraction of these metals gradually expanded. World,War II created an in t e r e s t i n chromium, molybdenum, and tungsten, metals which can be alloyed with i r o n to make various grades of st e e l (Gunn 1978). A l l three major f o s s i l f u e l s - co a l , o i l , and natural gas - are found i n B r i t i s h Columbia. C Q a l was f i r s t . 187 discovered on Vancouver Island over a century ago, but since then has been found i n many other parts of the province (Figure 98). At present, most of our coal i s exported to other countries, but i n the future-we may s t a r t to use i t within the province f o r the generation of e l e c t r i c i t y . . O i l and natural gas, found mostly i n the northeastern part of B r i t i s h Columbia near Fort St. John, Fort Nelson, and Dawson Creek, were f i r s t produced i n commercial quantities i n the early 1950's. Today, we appear to have enough natural gas to f i l l our needs f o r some years to come. The o i l however, i s being used up r a p i d l y . Unless large new discoveries are made, we w i l l very soon have to import a l l of our o i l from other parts of Canada and the world (Gunn 1978). Mining f o r other materials such as metal ores depends very much on the world demand. For example, i f the world p r i c e f o r copper i s high, then operating a copper mine i s worthwhile. I f the world p r i c e drops so that the mine owners can not make enough money to pay a l l expenses and produce a p r o f i t , then the mine must be closed. Every year, new mines open and others close as the world demand f o r various materials changes. Mining, and i t s r e l a t e d i n d u s t r i e s such as smelting and r e f i n i n g , i s one of B r i t i s h Columbia's most important income producers. Of every d o l l a r earned i n B.C., approximate! 230 comes d i r e c t l y or i n d i r e c t l y from mining. (For comparison, i n 1978 530 came from f o r e s t r y , and 180 from tourism). For some small towns l i k e Stewart or Logan Lake, t h e i r e n t i r e 183 ^ c o a l f i e l d Figure 98. Columbia. Locations of c o a l f i e l d s i n B r i t i s h 189 1 9 0 existence depends on the nearby mine. I f the mine closes, the people leave and the town becomes a "ghost town". Mining gave our province i t s s t a r t i n 1 8 5 8 , and w i l l continue to play an important part i n our development f o r many years into the future. Questions 1 . I f your town depends on a mine, write a short paragraph about the material produced, and about what happens to t h i s material once i t leaves the mine. 191 DISCUSSION It was the c l e a r intent of the author of t h i s thesis to write a p r a c t i c a l curriculum which could be put to immediate use by classroom teachers. To ensure that t h i s would be possible, the proposed curriculum was classroom tested and modified during two sucessive school years before reaching i t s present form. I n i t i a l t e s t i n g took place during 1.977-78, followed by extensive modification and further t e s t i n g i n 1978-79. Most of these t r i a l s took place i n Moody Junior Secondary School, a junior high school located i n Port Moody, B r i t i s h Columbia, e n r o l l i n g some seven hundred students i n grades 8, 9, and 10. The timetable system under which t h i s school operates i s based on the d i v i s i o n of the school year into four quarters, each of which contains approximately 46 i n s t r u c t i o n a l days. Classes meet f o r one hour each day f o r an entire quarter. This p a r t i c u l a r timetable system f a c i l i t a t e d t e s t i n g of the proposed curriculum by making i t possible to introduce each part as a science, "option" course f o r students having a p a r t i c u l a r i n t e r e s t i n earth science. Part 1 was introduced f o r grade 8 students, while Part 2 was a v a i l a b l e as a more advanced course f o r students i n grade 10. Completion of Part 1 was not required as a prere q u i s i t e f o r taking Part 2. During 1978-79, 32 students from grade 8, and 74 from grade 10 enrolled i n the course. In addition to the t e s t i n g which took, place i n Moody Junior Secondary, large portions of the proposed 192 were tested by other p r a c t i s i n g classroom teachers i n other schools. The results, of these t e s t s were incorporated into the.proposed curriculum. At t h i s point, the author would l i k e to extend his thanks to Mr. A. J . Williams of Dr. Charles Best Junior Secondary School, and Mr. S. K e l l a s of Centennial High School f o r t h e i r invaluable assistance with t h i s task. A copy of Part 2 of the proposed curriculum was sent to P r e n t i c e - H a l l of Canada Ltd., and subsequently d i s t r i b u t e d by them to f i v e anonymous teachers f o r testing.and review. A number of the changes suggested by these people have also been incorporated into t h i s present version. Here, the author wishes to thank Ms. S. Sparling of P r e n t i c e - H a l l , and her f i v e anonymous teachers f o r t h e i r appraisal and commentary. Since the proposed curriculum contained a great many top i c s not presently a part of the p r o v i n c i a l l y prescribed curriculum f o r j u n i o r high school science, no comparitive t e s t i n g or s t a t i s t i c a l analysis could be c a r r i e d out. However, i f i t i s f i n a l l y published and adopted by the Ministry of Education, s t a t i s t i c a l t e s t i n g and analysis may prove to be a f r u i t f u l area f o r f u r t h e r research. GENERAL CONCLUSION An examination of the earth science sections of the presently prescribed junior secondary school science curriculum i n B r i t i s h Columbia showed a lack of current plate tectonic theory, and an i n s u f f i c i e n t number of 193 references to l o c a l phenomena. In order to f i l l a need perceived by the author, the B.C. Ministry of Education, and Prentice-Hall of Canada Ltd., a laboratory centred curriculum was devised, based upon the most recently avai l a b l e accpted theory, and wherever possible i l l u s t r a t e d with examples from B r i t i s h Columbia. Over a period of two school years, t h i s curriculum was tested and revised i n a number of junior secondary schools, and found to be su i t a b l e at the Grade 8 and Grade 1 0 l e v e l s . 194 Teachers' Manual and Answer Key Part 1 1.95 THE WORLD OF HOCK General .objectives of the s e c t i o n : A f t e r completing t h i s u n i t , the student should be able t o : a) State reasons f o r the n e c e s s i t y of a c l a s s i f i c a t i o n system f o r r o c k s . b) Describe the o r i g i n of sedimentary, v o l c a n i c , . p l u t o n i c and metamorphic r o c k s . ' -c) On s i g h t , c l a s s i f y common rocks i n t o one of the groups named i n (b) above. d) On s i g h t , name a l i m i t e d number of common ro c k s . INVESTIGATION 1 O b j e c t i v e : A f t e r completing t h i s e x e r c i s e , the student should have developed an i n c r e a s e d a b i l i t y to observe and re c o r d data. M a t e r i a l s Required At l e a s t one sample each of the f o l l o w i n g types of rock: Sedimentary: conglomerate, b r e c c i a , sandstone, s h a l e , limestone, c o a l . P l u t o n i c : g r a n i t e , d i o r i t e , gabbro, porphyry. V o l c a n i c : r h y o l i t e , a n d e s i t e , b a s a l t , o b s i d i a n , pumice. Metamorphic: q u a r t z i t e , s l a t e , marble, g n e i s s . To reduce l o s s , and f o r ease of o b s e r v a t i o n , samples should have a minimum s i z e of 1 0 cm x 1 0 cm x 5 cm. Teaching Suggestions Encourage the students t o use proper d e s c r i p t i v e terms. They should avoid the use of words i n v o l v i n g value judgements 1 9 6 such as "pretty" or "ugly". Answers to Questions 1 . Two people may sometimes disagree on what to c a l l the colour of a rock. 2. The problem could be solved by s e t t i n g up a series of standardized colours. INVESTIGATION 2 Objectives: After•:completing t h i s exercise, the student should be able to: a) organize discrete observations into a coherent c l a s s i f i c a t i o n system. b) explain the reasons f o r the necessity of such a system. Materials Required Rock samples used f o r I n v e s t i g a t i o n 1. Teaching Suggestions T e l l the students to use t h e i r data from Investigation 1, but allow them to look at the specimens again i f they wish to do so. Answers to Questions 1. D i f f e r e n t students probably made up d i f f e r e n t groups. 2. Some samples may possibly have f i t t e d i n t o more than one group. 3. Some students may have had d i f f i c u l t y i n deciding i n which group to place a sample. 4-. Geologists using d i f f e r e n t methods of grouping rocks would have d i f f i c u l t y i n communicating with each other. They • 1 9 7 c o u l d s o l v e t h i s p r o b l e m b y s e t t i n g u p a s t a n d a r d i z e d g r o u p i n g s y s t e m . N A R R A T I V E 3 O b j e c t i v e : A f t e r r e a d i n g t h i s n a r r a t i v e , t h e s t u d e n t s h o u l d b e a b l e t o d e s c r i b e t h e o r i g i n o f s e d i m e n t a r y , i g n e o u s a n d m e t a m o r p h i c r o c k s . T e a c h i n g S u g g e s t i o n s T h i s n a r r a t i v e i s i n t e n d e d m a i n l y a s p r e - r e a d i n g f o r I n v e s t i g a t i o n 4. A n s w e r s t o Q u e s t i o n s 1. T h e p r e s e n c e o f l a y e r s s h o w s t h a t t h e r o c k s i n F i g u r e 6 a r e p r o b a b l y s e d i m e n t a r y . 2. F o s s i l s a r e f o r m e d w h e n a n i m a l s o r p l a n t s a r e b u r i e d i n s e d i m e n t w h i c h l a t e r h a r d e n s i n t o r o c k . 3. F o s s i l s s e l d o m f o r m i n i g n e o u s r o c k b e c a u s e t h e h e a t w o u l d d e s t r o y t h e a n i m a l . o r p l a n t . I N V E S T I G A T I O N 4 O b j e c t i v e : A f t e r c o m p l e t i n g t h i s e x e r c i s e , t h e s t u d e n t s h o u l d b e a b l e t o c l a s s i f y r o c k s a s s e d i m e n t a r y , p l u t o n i c , v o l c a n i c o r m e t a m o r p h i c . M a t e r i a l s R e q u i r e d R o c k s a m p l e s u s e d f o r I n v e s t i g a t i o n 1. H a n d l e n s e s o r s t e r e o s c o p i c m i c r o s c o p e s . T e a c h i n g S u g g e s t i o n s I n t r o d u c e t h i s i n v e s t i g a t i o n b y u s i n g t h e s t u d e n t s ' o w n c l a s s i f i c a t i o n s y s t e m s f r o m I n v e s t i g a t i o n 2. A s k o n e 198 student to l i s t the specimen numbers from one of his groups. Place the rocks where a l l students can see them, then ask another student to guess the method by which these rocks were grouped together. A f t e r they have t r i e d t h i s a few times, usually with mixed success and f a i l u r e , introduce the idea that geologists a l l over the world have agreed upon a single c l a s s i f i c a t i o n system. Answers to Questions 1. Sediment i s pieces of broken down rock. I t can be formed into new rock when squeezed and cemented. 2. Igneous rock i s formed when molten rock cools and hardens. 3. Metamorphic rock forms when another rock i s changed from i t s o r i g i n a l form by heat and pressure. 4. Volcanic rock cools r a p i d l y , forming small c r y s t a l s . Plutonic rock cools slowly, forming large c r y s t a l s . Student References Zinf, H ; S. and Shaffer, P. R., Rocks and Minerals. Golden Press, New, York, 1957. NARRATIVE 5 Objective: A f t e r reading t h i s n a r r a t i v e , the student should be able to i d e n t i f y a number of common rocks. Teaching Suggestions This narrative i s intended mainly as pre-reading f o r Investigation 6. Answers to Questions 1. The rocks shown are: Figure 1 sandstone; Figure 2 conglomerate; Figure 3 granite; Figure 4 - b a s a l t ; Figure 5. 1 9 9 gneiss. : 2. Student d e f i n i t i o n s w i l l d i f f e r widely. A t y p i c a l one might be, "A rock i s a piece of hard s t u f f found i n the ground". INVESTIGATION 6 Objective: After completing t h i s exercise, the student should be able to i d e n t i f y a number of common.rocks. Materials Required Rock samples used f o r Inv e s t i g a t i o n 1. Hand lenses or stereoscopic microscopes. D i l u t e hydrochloric acid (1.0 M) i n dropper b o t t l e s . Teaching Suggestions Correct the students' r e s u l t s from Investigation 4-before proceeding with t h i s exercise. Point out that the names they are learning are only a few of the hundreds used by g e o l o g i s t s . The precise name of a rock usually depends upon i t s mineral content, but since mineralogy i s not a part of t h i s course a simpler system based on colour and grain s i z e has been developed. Do not allow u n r e s t r i c t e d access to the acid b o t t l e s . Answers to Questions 1. Granite has l a r g e r c r y s t a l s than r h y o l i t e . 2. Slate i s usually harder than shale. 3 . Slate i s used as a roofi n g material because i t s p l i t s into t h i n f l a t sheets which may be used l i k e shingles. 4-. Shale i s more l i k e l y to contain f o s s i l s than andesite. 5 . Limestone and marble both f i z z with d i l u t e a c i d . 200 6. Pumice i s f u l l of bubbles, whereas obsidian Is massive. 7. Obsidian i s usefu l f o r arrowheads because i t takes a very sharp edge. • Student References Zim, H. S. and Shaffer, P. R., Rocks and Minerals. Golden Press, New York, 1957. THE WORLD OF GEOLOGIC MAPPING General Objectives of the Section: After completing t h i s u n i t , the student should be able to: a) read a geologic map to obtain information about the bedrock i n a p a r t i c u l a r area. b) read a topographic map. INVESTIGATION 7 Objective: Aft e r completing t h i s exercise, the student should be able to read a geologic map to determine the type of bedrock i n a p a r t i c u l a r area. Materials Required Class set of geologic maps. This exercise as written uses Geologic Survey of Canada map 1153A Coquitlam, but t h i s may be changed to s u i t l o c a l needs. Coloured p e n c i l s . Teaching Suggestions Introduce t h i s section with the "Mystery Mapping Exercise". Chalk a simple coloured pattern on the blackboard. Cover t h i s with a large piece of brown paper taped to the board. Each student i n turn i s asked to point out a place 201 on the paper. Use a razor blade ( c a r e f u l ! ) to cut a 1. cm square from the paper at t h i s point, exposing the colour below. A l l the students then record t h i s information on t h e i r own pieces of paper. As the exercise progresses, students w i l l s t a r t to choose t h e i r l o c a tions more c a r e f u l l y to obtain information about the colours below. When each student has had a turn, ask them to reconstruct the hidden pattern from t h e i r l i m i t e d amount of information. After a few minutes, remove the paper from the board so they can compare t h e i r patterns with the o r i g i n a l . Point out the s i m i l a r i t y between t h i s exercise and the way i n which a geologist constructs a map from obsrevations recorded at a l i m i t e d number of rock outcrops. Answers to Questions 1. Geologic maps use colours because the d i f f e r e n c e s between areas on the map are more v i s i b l e at a glance. 2. I t i s usually impossible f o r a geologist to examine the rock i n every part of an area. J. Vegetation or water could cover the rock. 4-. Usually, a geologist can hot be absolutely sure of the rock i n a l l parts of an area. NARRATIVE 8 Objective: A f t e r reading t h i s n a r r a t i v e , the student should be able to explain the d i f f e r e n c e between a geologic map and a topographic map. Answers to Questions 1. Topographic maps are made from a e r i a l photographs because 2 0 2 mapping from ground notes would take too long i n a country as large as Canada. 2 . Topographic maps must be revised more frequently than geologic maps because ground l e v e l features such as roads and buildings may change frequently, whereas bedrock does not change, except i n the case of an error i n the o r i g i n a l geologic map. INVESTIGATION 9 Objective: A f t e r completing t h i s exercise, the student should be able to use the legend to obtain information about c u l t u r a l symbols on a topographic map. Materials Required Class set of topographic maps. This exercise uses National Topographic Series map 9 2 G/7, but t h i s may be modified to s u i t l o c a l needs. Answers to Procedure Questions A. 1 . Blue represents water, green represents vegetation, white represents non-forested area, and red represents a b u i l t - u p area. 2 . The symbols are: . , school C3 mine 5? church i quarry post o f f i c e Pa navigation l i g h t # 3. The symbols are: four lane freeway = = = = = t r a i l s ingle track railway — i — i i i — t — 203 double track railway u—H—H—H—«-power transmission l i n e — • c i t y boundary 4. Within the boundaries of Port Moody there are: 8 schools 1 o i l r e f i n e r y 5 churches 1 winery ' 1 sawmill 1 post o f f i c e 0 mines 1 navigation l i g h t INVESTIGATION 10 Objective: Aft e r completing t h i s exercise, the student should be able to measure scale distances on a topographic map. Materials Required Maps used f o r Investigation 9. Teaching Suggestions Introduce t h i s exercise by showing a number of maps of the same area, each drawn to a d i f f e r e n t scale. Answers to Procedure Questions A. 1. The scale of t h i s map i s 1:50 000 3. a) 2500 m f ) 1000 m b) 1100 ra g) 900 m c) 3900 ra h) 5000 m d) 300 m i ) 20 000 m e) 800 m j ) 760 000 m2 INVESTIGATION 11 ' Objective: Aft e r completing t h i s exercise, the student should be able to read a l t i t u d e from a topographic map. 204 'Materials Required Maps used f o r Investigation 9« Teaching Suggestions ^ Avoid spending too much time on the meaning of contour l i n e s . Most students can learn to use them i n a •mechanical way quite quickly. Answers to Procedure Questions Buntzen Lake 407 f t Mount Burke .782 f t Burwell Lake 2 7 2 0 Coquitlam Mountain 5 1 9 3 Mount Bishop 4946 Widgeon Peak 4 7 0 1 Mount Elsay 4 6 5 3 Golden Ears 5 5 9 8 Mount Seymour 4 7 6 6 Coquitlam Lake 511 Seymour Lake 7 5 0 unnamed peak 4546 Eagle Mountain 5400 f t H i l l N of Burns Point 9 0 0 f t Burnaby Mountain 1 1 0 0 H i l l E of Bedwell Bay 5 0 0 C a p i t o l H i l l 600 Gopher Lake 2800 Mount F e l i x 5 8 0 0 Croker Island 400 Cypress Lake 2 5 0 0 Moody J r . Sec. School 1 0 0 Cypress Mountain 2600 Sheridan H i l l 400 Dennett Lake 3 1 0 0 Mount Dickens 2800 Obelisk Peak 5800 Mike Lake 800 . Coquitlam Island 1 0 0 0 Widgeon Lake 2600 Answers to Questions 1... A person; hiking along a contour l i n e would be walking along a l e v e l path. 2. Contour l i n e s can never cross because that would mean the crossing point had two d i f f e r e n t a l t i t u d e s . 5 . Sea l e v e l would have an a l t i t u d e of 0 m. , 2 0 5 INVESTIGATION 1 2 Objective: After completing t h i s exercise, the student should be able to draw a land p r o f i l e by using the contour l i n e s on a topographic map. Materials Required Maps used f o r Investigation 9 F u l l page copy of Figure 1 0 5 Teaching Suggestions Introduce the exercise by drawing a very simple p r o f i l e on an overhead projector mock-up, while the students follow along on t h e i r own copies. Remind the students that i f the g r i d l i n e s on the p r o f i l e sheet are not drawn on the same scale as the map, the steepness of the t e r r a i n may be exaggerated or reduced (usually exaggerated). Answers to Procedure Questions See Figure 1 0 0 . THE WORLD OF WEATHERING AND EROSION General Objectives of the Section: After completing t h i s u n i t , the student should be able to: a) describe the gradational processes working to reduce the r e l i e f of the land. b) describe the sedimentation processes r e s u l t i n g from ( a ) . -NARRATIVE 1 3 Objective: Aft e r reading t h i s n a r r a t i v e , the student should 206 f o l d along: 1 1—I T " ~ L i n e 8 § 8 o o ~ M M W o JJ o o 3 o .8 § o o o o 0 2 0 7 . be able to c l a s s i f y weathering processes as physical, chemical or b i o l o g i c a l . Answers to Questions 1. Three ways i n which rock can be weathered by non-living things are: a) Rainwater may diss o l v e rock. b) Water freezing may wedge rocks apart. c) Windblown sand may grind rock away. There are of course many others. 2. Three ways i n which l i v i n g things may weather rock are: a) Roots may wedge rocks apart. b) Animals 1 feet may.wear rock away. c) Earthworms pass rock p a r t i c l e s through t h e i r digestive t r a c t s , making the p a r t i c l e s smaller. There are many other methods. 3. Lichen r e l e s i n g acid would probably be considered a combination of b i o l o g i c a l and chemical weathering. Student References Boyer, Robert E., F i e l d Guide to Rock Weathering, ESCP Pamphlet Series PS - 1, Houghton M i f f l i n Co., Boston, 1 9 7 1 . INVESTIGATION 14-Objectives: A f t e r completing t h i s exercise, the student should be able to define the word weathering, and c l a s s i f y weathering processes as p h y s i c a l , chemical or b i o l o g i c a l . Materials Required metal capped glass b o t t l e freezer s t e e l wool 3 beakers and covers 208 limestone chip d i l u t e hydrochloric acid.(1.0 M) pl a s t e r of p a r i s soaked corn or bean seeds Teaching Suggestions Stress the difference between weathering - the break-down of rock, and erosion - the removal of rock debris. Answers to Procedure Questions A. Weathering i s the process by which large pieces of rock are broken down int o small pieces of rock. B. The b o t t l e broke. This occurred because the water expanded upon fr e e z i n g . This i s an example of ph y s i c a l weathering. C. The dry wool i n the dry beaker remained unchanged because there was no re a c t i o n between the s t e e l and oxygen. The wool i n the beaker of water rusted because of a reac t i o n between s t e e l and dissolved oxygen i n the water. The damp wool i n the dry beaker rusted because the wool rected with oxygen i n the a i r . These demonstrations are examples of chemical weathering. D. The limestone l o s t I t s sharp edges, becoming s l i g h t l y smaller. This occurred because of a r e a c t i o n between the limestone and the acid, representing chemical weathering. E. The sprouting seeds broke t h e i r way out of the p l a s t e r because of expansion upon growth. This represents b i o l o g i c a l weathering. Answers to Questions 1. Two examples of b i o l o g i c a l weathering are roots s p l i t t i n g rock and animals feet wearing rock away. 2. Two examples of phys i c a l weathering are windblown sand wearing away rock, and running water tumbling and wearing rock. 209 3. Acid r a i n w i l l slowly dissolve limestone. The chemical reactions associated with the process are: carbon , .' ^ carbonic dioxide + w a t e r -* acid C0 2 + H 20 — • H 2C0 5 carbonic , T^„„„4--^„« calcium acid + limestone -» bicarbonate (soluble) H 2C0 5 + CaCOj —> Ca(HC0 5) 2 These equations are f o r the use of the teacher. They are not intended to be discussed by the students. 4-. Acid r a i n w i l l slowly di s s o l v e stone facings on b u i l d i n g s . •5» This combination of weather conditions w i l l cause f r o s t wedging which weathers rock. Student References Boyer, Robert E., F i e l d Guide to Rock Weathering, ESCP Pamphlet Series PS - 1, Houghton M i f f l i n Co., Boston, 1 9 7 1 -INVESTIGATION.15 Objective: A f t e r completing t h i s exercise, the student should be able to describe the operation of the hydrologic c y c l e . Materials Required . .• small aquarium rocks glass cover f o r aquarium heat lamp i c e . t r a y Teaching Suggestions Set up the apparatus (Figure 101 ) at l e a s t an hour before i t i s required. After completing the exercise, guide cl a s s discussion by drawing a composite of the students' 210 Figure 101a. Hydro-logic cycle apparatus f o r Investigation 15« 211 hydro-logic cycles on a blackboard or overhead projector. Answers to Procedure Questions -A. See Figure 101a. B. a) The l i g h t bulb represents the sun. b) The ice tray represents the cold upper atmosphere. c) The water represents the oceans. d) The rocks represent the land. C. Water droplets form beneath the i c e tray. These return to the bottom of the tank by dropping, representing r a i n . D. Mist forms on the sides of the tank. Water t r a v e l s upwards by evaporation, s i m i l a r to the process on Earth. Water t r a v e l s back to Earth i n the form of r a i n , or i n the form of snow i f the temperature i s l e s s than 0°G. Answers to Questions 1. The average water use w i l l probably be about 360 L, but t h i s can vary widely. 2. 360 x 365 = 131 400 L. 3. 131 400 x 22 000 000 = 2 890 800 000 000 L.' NARRATIVE 16 This narrative i s intended to supply the student with a number of a d d i t i o n a l f a c t s about the hydrologic c y c l e . INVESTIGATION 17 Objectives: A f t e r completing t h i s exercise, the student should be able to describe the causes of stream abrasion, and describe the e f f e c t s of stream abrasion on rock. 212 Materials Required (per group) 100 — 200 g of crushed limestone, washed free of s i l t and f i n e p a r t i c l e s . A generous supply of paper towels.. Equipment Required (per group) centigram balance p l a s t i c container Teaching Suggestions Make sure that the students shake the container s u f f i c i e n t l y hard. Gentle "sloshing" i s not s u f f i c i e n t . Answers to Questions 1. The rocks were soaked beforehand so that absorption of water during the experiment would not obscure the r e s u l t s . 2. The shaken rocks w i l l be smoother, with fewer sharp edges. 3. A "very large number" of shakes would be required to wear the rock away completely. 4. The causes of the abrasion are f i r s t l y , abrasive contact with other rocks and the sides of the container and secondly, d i s s o l v i n g of a small amount of the limestone by the water. 5- Abrasion causes scarring and rounding of the rocks, and a s l i g h t reduction i n mass. 6. Stream abrasion i s most l i k e l y to occur i n l a t e spring and early summer when melting snow causes a high rate of flow i n streams and r i v e r s . INVESTIGATION 18 Objectives: Aft e r completing t h i s exercise, the student should be able to state i n which months the Fraser River 213 c a r r i e s the most sediment. Materials Required graph paper Answers to Procedure Questions A. The Fraser River i s approximately 1370 km long. Answers to Questions 1. The Fraser c a r r i e s an average 6 900 000 t of sediment during June. 2. Water flow i s higher i n June than i n February, therefore the r i v e r can carry more sediment. 3. a) Each t r a i n c a r r i e s 10 000 t of sediment. b) 2000 t r a i n s would be needed each year. c) Approximately 5«5 t r a i n s would be needed each day. d) 23 t r a i n s each day, Or approximately one t r a i n per hour would be required. . INVESTIGATION 19 Objectives: A f t e r completing t h i s exercise, the student should be able to state i n which months the Fraser River c a r r i e s the most and l e a s t water. Materials Required graph paper Answers to Procedure Questions B. The high and low points occur i n the same months f o r both water and sediment flow. The s i m i l a r i t y occurs because the greater water flow can carry more sediment. Answers to Questions 1. a) 527 400 m5/minute 214 b) 31 644- 000 m^/hour c) 759 460 000 m5/day . d) 22 784- 000 000 m5/ month 2. The greatest water flow occurs i n June because the warm weather i s melting the winter snowpack. NARRATIVE 20 Objective: Aft e r reading t h i s n arrative, the student should be able to describe the three d i f f e r e n t ways i n which a r i v e r may carry sediment. Answers to Questions 1. Sediment.carried by a r i v e r eventually ends up i n a large lake (temporarily) or i n the ocean. 2. The amount of sediment c a r r i e d by a r i v e r could be affected by the water speed, the- quantity of water, and the type of material over which the r i v e r flows. INVESTIGATION 21 Objectives: A f t e r completing t h i s exercise, the student should be able to: a) State the meanings of bed, suspended and dissolved sediment load. b) Determine the amount of suspended and dissolved sediment i n a water sample. Materials Required f i l t e r paper bucket of muddy water Equipment Required (per group) centigram balance graduated c y l i n d e r funnel 215 r i n g stand and r i n g evaporating dish asbestos gauze bunsen burner Teaching Suggestions Emphasize accuracy i n weighing. Do not overheat the evaporating dish, otherwise spattering may occur. Answers to Q u e s t i o n s 2 . The average sediment load of Fraser River water i s 0 . 2 5 g/L. 5 . When dissolved, the molecules of sediment are so evenly d i s t r i b u t e d i n the water that t h e i r s i z e makes them i n v i s i b l e . 4. a) Sediment c a r r i e d by a braided stream i s mostly bed load. b) The greatest amount of sediment i s c a r r i e d i n l a t e spring or early summer when the water flow i s greatest. INVESTIGATION 2 2 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Describe the processes of v a l l e y formation b) Describe the r e l a t i o n s h i p between water speed and v a l l e y shape. c) Describe the formation of a meandering r i v e r and an oxbow lake. Equipment Required (per c l a s s ) stream table Teaching Suggestions For best operation of a stream table, the sand should be f a i r l y f i n e and free of s i l t . The water should run slowly. 216 Answers to Procedure Questions A. The r i v e r s appear to be flowing r a p i d l y . The v a l l e y has the shape of the l e t t e r V. B. The r i v e r cuts a deep narrow v a l l e y . The r i v e r i n Figure 1.15 probably flowed r a p i d l y . C. The r i v e r s appear to be flowing slowly. The Fraser Val l e y i s wade and f l a t . D. The r i v e r s appear to flow slowly. E. The water continues to make a wide f l a t v a l l e y . Slow r i v e r s form wide f l a t v a l l e y s . F. Oxbow lake formation s\ s~i n o . Answers to Questions 1. A r i v e r can erode a deep canyon by tumbling rocks and sediment against the bottom and sides. 2. A f a s t r i v e r i n a deep rock canyon would probably erode i t s bottom more than i t s sides. 5. A slow r i v e r i n a.valley of s o f t s o i l would probably erode i t s sides more than i t s bottom. INVESTIGATION 25 Objectives: A f t e r completing t h i s exercise, the student, should be able to: a) Describe the formation of deltas and f l o o d p l a i n s . b) Describe the geologic hazards associated with 2 1 7 deltas and flood p l a i n s . c) Describe the a g r i c u l t u r a l advantages of deltas and flood p l a i n s . Materials Required Map, National Topographic System 92G F u l l page copy of Figure 9 Teaching Suggestions If possible;, introduce the exercise by showing a colour s l i d e of Figure 10 Discuss the appearance of the sediment, and what happens to i t once i t reaches the ocean. Answers to Procedure Questions B. Spanish Bank, Sturgeon Bank and Roberts Bank are probably growing. The Boundary Bay t i d a l f l a t s are probably not growing. C. Water i s ava i l a b l e to vegetation i n the d e l t a area. D. Aklavik has been abandoned because of repeated f l o o d i n g . E. Deltas are suitable f o r industry because of t h e i r closeness to water transportation. F. The water path varies when depositing the sediment. Answers to Questions 1. a) The greatest water flow occurs i n l a t e spring or e arly summer because the•warm temperatures melt the winter snowpack. b) The winter temperature a f f e c t s the rate of water flow by f r e e z i n g the r i v e r s . 2 . a) A fl o o d p l a i n i s a good place f o r ag r i c u l t u r e because of the f e r t i l i t y of the sediment deposited there. 218 b) L i v i n g on a fl o o d p l a i n i s hazardous because of the floods! c) Floods could be prevented by damming the r i v e r upstream, or by b u i l d i n g dykes, d) I f floods are prevented, f e r t i l i t y of the s o i l w i l l d e c l ine. 3. a) Heavy sediment w i l l be dropped close to the r i v e r . b) Fine sediment w i l l be dropped f a r t h e r out to sea. 4-. A dam across.the Fraser would eventually s i l t up. NARRATIVE 24-Objective: After reading t h i s narrative, the student should be able to describe a set of conditions under which a d e l t a i s b u i l t at the out l e t of a lake. INVESTIGATION 25 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Describe the c h a r a c t e r i s t i c s of a sand. b) Relate a sand to i t s o r i g i n a t i n g rock. Materials Required sample of o l i v i n e a number of d i f f e r e n t sands (Hawaiian recommended) Equipment Required cl a s s set of hand lenses or stereomicroscopes p e t r i dishes GSG Map 1153A (from Investigation 7) Teaching Suggestions Every time a f r i e n d , acquaintance or student goes to Hawaii, give him three v i a l s and ask him to bring back sand 2 1 9 samples. After a while, you w i l l have enough to make t h i s exercise possible. The l o c a l sample may come from just about any stream, provided you can obtain a geologic map of the upstream area. Do not allow u n r e s t r i c t e d access to the acid b o t t l e s . Answers to Procedure Questions D. Widgeon Lake i s surrounded by granodiorite and quartz d i o r i t e . The colour of the sand sample resembles these rocks. E. Basalt i s black with small c r y s t a l s . F. The green sand most c l o s e l y resembles o l i v i n e . Answers to Questions 1. The sand at a r i v e r mouth i s made from weathered upstream rocks. 2 . Grains of soft minerals are seldom found i n sands because they are generally washed away. 3- This sand would form limestone, then marble. 4- . The black sands come from basalt, a volcanic rock. NARRATIVE 26 Objective: Aft e r completing t h i s exercise, the student should be able to describe a catastrophic form of erosion. Teaching Suggestions Very l i t t l e i n troduction i s usu a l l y required. The story i s quite gripping. Answers to Questions 1. Coal was being mined i n T u r t l e Mountain. 2 . T u r t l e Mountain was made of limestone. 3 . a) Water can cause cracks by f r e e z i n g and expanding 220 b) Mining could help cause the s l i d e by weakening the mountain. 4. The s l i d e debris could form b r e c c i a . Student References Anastasiou, C l i f f o r d et a l , Reading About Science 1, Holt Rinehart and Winston, 1968. Chapter 51 t e l l s about the Hope S l i d e . THE WORLD OF ANCIENT LIFE General Objectives of the Section A f t e r completing t h i s section, the student should be able to: a) Describe a generalized h i s t o r y of l i f e on Earth. b) Identify a l i m i t e d number of common f o s s i l s . c) Describe a number of methods of f o s s i l preservation. d) Describe some l i f e forms and environmental conditions of the Mesozoic Era. NARRATIVE 2? Objective: a f t e r reading t h i s n a r r a t i v e , the student should be able to name the p r i n c i p a l d i v i s i o n s of the Earth's h i s t o r y . > Teaching Suggestions This narrative i s intended mainly as pre-reading f o r the following exercises. INVESTIGATION 28 Objective: Aft e r completing t h i s exercise, the student should 2 2 1 be able to name the three eras of the Phanerozoic Eon, and to describe the main l i f e forms of each era. Teaching Suggestions , - ' Emphasize how l i t t l e we r e a l l y know about most of the E a r t h 1 s h i s t o r y . A l l of our evidence comes from studying the rocks and the f o s s i l s they contain. The reference given below contains a very l i m i t e d amount of information. Students who complain that there i s no d e s c r i p t i o n of the Cenozoic Era should be reminded that they are l i v i n g i n i t . Student Reference Anastasiou, C l i f f o r d et a l , Reading About Science 1, Holt, Rinehart and Winston, 1968. Chapter 53• INVESTIGATION 2 9 Objective: Aft e r completing t h i s exercise, the student shoould be able to describe the d i v e r s i t y of f o s s i l l i f e . Materials Required As large a v a r i e t y of f o s s i l s as p o s s i b l e , preferably with some rock matrix s t i l l attached. Teaching Suggestions F o s s i l s you have personally c o l l e c t e d are f a r more use f u l than commercial specimens. Students w i l l almost i n v a r i a b l y ask where a p a r t i c u l a r specimen came from, and i t adds to t h e i r i n t e r e s t i f you can r e l a t e a personal anecdote. Mammalian c o p r o l i t e s , a v a i l a b l e from Wards S c i e n t i f i c , are an invaluable i n t e r e s t generator i n any c o l l e c t i o n ! Your questions should be t a i l o r e d to the specimens, 222 but could include such thought provoking t o p i c s as: What i s i t ? What present day l i f e form does i t resemble? Why might sea l i f e be found i n the mountains? What- was the climate at the time the f o s s i l was al i v e ? Student Reference Beerbower, James R., F i e l d Guide to F o s s i l s , ESCP Pamphlet Series PS-4, Houghton M i f f l i n Co., Boston, 1 9 7 1 . INVESTIGATION $0 Objective: Aft e r completing t h i s exercise, the student should be able to i d e n t i f y a number of common f o s s i l s . Materials Required ' f o s s i l specimens (per group) t r i l o b i t e gastropod c r i n o i d stem horn c o r a l pelecypod shark tooth brachiopod ammonite r e p t i l e bone gymnosperm l e a f angiosperm l e a f Loss may be reduced i f the smaller specimens are enclosed i n Riker mounts. Teaching Suggestions If possible, provide the students with the age of each specimen,and the approximate l o c a t i o n where i t was found. L i t t l e i s to be gained by taking j u n i o r secondary students on actual c o l l e c t i n g t r i p s , e s p e c i a l l y i f the s i t e v i s i t e d i s at a l l f r a g i l e . Many good f o s s i l l o c a l i t i e s have been ruined by indiscriminate c o l l e c t i n g . 223 Answers to Procedure Questions A. a) " T r i " suggests the number-three. A ' t r i l o b i t e * s body i s divided i n t o three parts. b) The t r i l o b i t e most c l o s e l y resembles a lob s t e r . B. a) A cor a l i s an animal. b) The small end of the c o r a l l i t e i s formed when the animal i s younger and smaller. c) S o l i t a r y corals l i v e alone, c o l o n i a l corals l i v e i n groups. C. a) A brachiOpod s h e l l has two parts. D. a) i ) A gastropod s h e l l has one par t . b) i ) Mussels and scal l o p s are both e d i b l e . c) i ) An ammonite s h e l l i s c o i l e d f l a t , while a gastropod s h e l l i s c o i l e d c o n i c a l l y ( u s u a l l y ) . F. a) A shark tooth i s pointed, while a human front tooth i s f l a t or c h i s e l shaped. G. a) The shape of the specimen resembles bone. The marrow may be v i s i b l e . b) The bone i s brown i n colour, and heavier than present day bone. H. a) Most leaves break apart r a p i d l y a f t e r f a l l i n g . c) Coal i s formed where t h i c k layers of vegetation are f o s s i l i z e d underground. Answers to Questions I. A f o s s i l i s preserved evidence of p r e h i s t o r i c l i f e . 2. F o s s i l s can t e l l us what kind of animals and plants l i v e d i n the past, and the environment and climate of the area i n which they l i v e d . 224 NARRATIVE 31 Objective: A f t e r reading t h i s narrative, students should be able to describe a number of methods by which f o s s i l s are formed. Teaching Suggestions This narrative should be considered as supplementary reading. Students at t h i s l e v e l frequently have d i f f i c u l t y d i s t i n g u i s h i n g among the various methods of preservation, therefore i t should be assigned.only to the most capable. INVESTIGATION 52 Objective: A f t e r completing t h i s exercise, the student should be able to describe some of the c h a r a c t e r i s t i c s of dinosaurs. Teaching Suggestions Dinosaurs are usually a popular t o p i c . Try to c a p i t a l i z e on t h i s by the use of supplementary books and posters. However, be wary of the p o s s i b i l i t y that the topic may already have been "done to death" i n previous grades. Answers to Procedure Questions A. In many cases, form of movement i s open to debate. I t depends c h i e f l y upon the animal's actions at a p a r t i c u l a r moment. (Even b i r d s spend a l o t of time walking or standing). B. a) Look at the teeth to. determine eating habits. b) Allosaurus and Tyrannosaurus appear to eat meat. Iguanodon and Camptosaurus appear to eat plants. c) The meat eaters probably ran, while the plant eaters probably walked. 225 C. a) Rhamphorhynchus would f l y away from danger. b) Monoclonius would defend i t s e l f with horn and head armour. c) Tyrannosaurus would e i t h e r run away or defend i t s e l f with i t s teeth. d) Ankylosaurus would crouch to protect i t s under-side, while using i t s t a i l as a club. D. a) Hesperosuchus i s the smallest at 7 0 cm high. b) Brachiosaurus i s the t a l l e s t at 16 m. . c) Diplodocus i s the longest at 3 0 m. d) Pteranodon's wing span i s approximately 12 m. E. Tyrannosaurus and Allbsaurus d i f f e r i n shape of head, length of teeth, length of arms, and number of f i n g e r s . F. a) Pteranodon and Rhamphorhynchus would have had l i g h t hollow bones so as to reduce t h e i r weight f o r ease of f l y i n g . b) Brachiosaurus would have had t h i c k heavy l e g bones to support i t s great bulk. NARRATIVE 53 Objective: Aft e r reading t h i s n a r r a t i v e , students should be able to describe conditions i n Dinosaur P r o v i n c i a l Park 76 m i l l i o n years ago. Teaching Suggestions Introduce t h i s narrative by asking students to give t h e i r impressions of conditions at t h i s time. Afterwards, the reading should d i s p e l some of t h e i r i l l u s i o n s about the l i k e l i h o o d of human s u r v i v a l . 226 Answers to Questions "1. B i t i n g insects, poisonous plants and predatory animals would make l i f e unpleasant. INVESTIGATION 54 Objective: Aft e r completing t h i s exercise, the student should be able to describe a number of possible reasons f o r the e x t i n c t i o n of the dinosaurs. Teaching Suggestions This i s an exercise i n c r e a t i v i t y . At present, the reasons f o r the massive e x t i n c t i o n at the end of the Mesozoic Era are not known. Students may propose floods, plague, lack of food, c l i m a t i c change or s i m i l a r catastrophes. Currently popular theories include c l i m a t i c change caused by continental d r i f t , or destruction of the ionosphere by geomagnetic r e v e r s a l or a nearby supernova, thereby exposing the Earth to harmful s o l a r r a d i a t i o n . THE WORLD OF ICE General Objectives of the Section: A f t e r completing t h i s u n i t , the student should be able to: a) Describe the appearance of Canada during the Ice Age. b) Describe the formation and structure of g l a c i e r s . . c) Describe the landforms caused by g l a c i a l erosion. INVESTIGATION 55 Objectives: Aft e r completing t h i s exercise, the student ( .' " - ' - •• 227 should be able to: a) Describe the appearance of Canada during the ice age. b) Name locations of present g l a c i e r s i n Canada. c) Describe the process of g l a c i e r formation. Materials Required Geologic Survey of Canada maps 1257A and 1253A Teaching Suggestions Introduce the section by asking students about t h e i r impressions of l i f e i n Canada during the ice age. I f snow i s a v a i l a b l e , demonstrate the formation of i c e by pressure. Answers to Procedure Questions D. G l a c i e r s may be found i n the P a c i f i c Coast Mountains, and the Rocky Mountains. Answers to Questions 1. a) The P a c i f i c Ocean provides the water f o r snow. b) The cold winds blow south from the A r c t i c . c) There are more g l a c i e r s i n the Coast Mountains because there i s a greater supply of water nearby. 2. a) Parts of the Yukon T e r r i t o r y were i c e f r e e . b) There was a lack of open water to evaporate and provide snow. 3. A n t a r c t i c a i s s t i l l ice covered. 4. In order to survive an i c e age, Canadians would probably have to move south. INVESTIGATION 56 Objective: A f t e r completing t h i s exercise, the student should 228 be able to: a) Describe the structure of a g l a c i e r . b) .Describe the mechanism of g l a c i a l erosion, and the formation of moraine. Materials Required a sample of g l a c i a l l y s t r i a t e d rock Answers to Procedure Questions A. A g l a c i e r i s a large mass of i c e formed on land. B. Mountain climbers may f a l l n i t o crevasses while crossing g l a c i e r s . C. The most snow f a l l s and the l e a s t snow melts at the upper end of a g l a c i e r . The l e a s t snow f a l l s and the most snow, melts at the lower end of a g l a c i e r . The g l a c i e r w i l l grow lar g e r at the upper end and smaller at the lower end. D. The fr e s h snow appears at the upper end of the g l a c i e r . The i c e . a t the snout of the Athabaska G l a c i e r i s melting. E. The p l a i n i c e does not scrape the board much, so i t i s not l i k e l y that p l a i n i c e can erode very much rock. Ice containing sand scraped the board more. Ice containing broken rock could erode more e a s i l y . F. Moraine describes a l l of the rock c a r r i e d by a g l a c i e r . G. A l a t e r a l moraine i s rock c a r r i e d along the side of a g l a c i e r . A medial moraine i s rock c a r r i e d i n the middle of a g l a c i e r . Six g l a c i e r s have joined to form the g l a c i e r •'j —j i n Figure Answers to Questions 1. G l a c i e r s are sometimes c a l l e d " r i v e r s of i c e " because they are made of i c e which flows slowly. 2 2 9 2 . The grooves i n g l a c i a l l y s t r i a t e d rock are caused by the g l a c i e r dragging rocks over the surface. 3 . a) The moraine i s p i l e d up at the snout of the g l a c i e r . b) The g l a c i a l flour- i s washed away i n the melt water. c) The streams flowing away from the g l a c i e r carry the g l a c i a l f l o u r as sediment. INVESTIGATION 37 Objective: After completing t h i s exercise, the student should be able to: a) Describe the mechanism of g l a c i a l erosion. b) Describe the formation of various g l a c i a l landforms. Teaching Suggestions Show the students as many photographs as possible of g l a c i a l landforms native to t h e i r home area. Answers to Procedure Questions A. This v a l l e y has a U-shape. I f the stream continues to flow, the v a l l e y w i l l become V-shaped. B. Snow enters a cirque by f a l l i n g i n t o the top. The i c e leaves a cirque when pressure forces i t over the edge. Ice makes a cirque l a r g e r by plucking rocks from the walls. There i s one cirque i n Figure 3 0 . C. There are two aretes v i s i b l e i n Figure 31 • D. There i s one horn v i s i b l e i n Figure 31 • E. There are two hanging v a l l e y s v i s i b l e i n Figure 3 1 . F. Fiords make good harbours because.they are sheltered and contain deep water. There are few sandy beaches because the sides of a f i o r d are so steep. The f i o r d north of Port 250 Moody i s c a l l e d Indian Arm. " Answers to Questions 1. A r i v e r erodes only the bottom of a v a l l e y , whereas a g l a c i e r erodes both the sides and the bottom. 2. The sea l e v e l was much lower during the i c e age because a large amount of water was locked up on land i n the form of i c e . 3 . A g l a c i e r carrying a large amount of very f i n e rock debris could p o l i s h rock. COQUITLAM RIVER FIELD TRIP Objective: to have the student observe i n the f i e l d some of the processes and landforms which have been studied i n t h i s course. Equipment Required (per group) notebook and p e n c i l , two water sample j a r s one sand sample v i a l Teaching Suggestions The a c t i v i t i e s and questions are phrased i n such a way that the student i s d i r e c t e d to observe a feature, then record the observations and deduce fu r t h e r information. On the t r i p , samples are taken which w i l l be analysed l a t e r . This forces a review of previous a c t i v i t i e s . . Answers to Questions Part B Stop #1. Two possible causes of a la n d s l i d e are (a) an over-steep slope weakened by heavy r a i n f a l l or (b) a minor earthquake i n the area. 231 Stop #2. a) At t h i s point the v a l l e y i s f a i r l y narrow with quite steep sides. There i s no good farmland. b) The r i v e r flows quite r a p i d l y here. c) The current i s f a s t e s t i n the middle of the r i v e r . d) The water (usually) does not carry much sediment here. e) The rocks are quite large (30 cm) and rounded. They acquired that shape by being tumbled by the water. They are mostly plutonic and metamorphic, d i o r i t e and gneiss, with a few volcanic b a s a l t s . Stop #3 a) The c l i f f i s made of sand and gravel with some lar g e r boulders. b) I f t h i s material were compressed i t would form sandstone and. conglomerate with po s s i b l y some shale. c) The large rocks are rounded, implying that the material was deposited by water,since stream abrasion rounds rocks. d) The coarse layers were deposited by f a s t water since only f a s t water could move the large boulders. The absence of boulders i n the f i n e r layers implies that they were deposited by slower moving water. Meltwater from i c e age g l a c i e r s could have produced the quantity of water required to deposit t h i s amount of sediment. e) The present r i v e r has removed the sediment from the centre of the v a l l e y . Drive to Stop #4-a) As we t r a v e l downstream, the v a l l e y widens. 232 b) A'major sand and gravel industry i s located here because of the quantity of su i t a b l e material and the ease with which It may be extracted. Sand and gravel i s used mainly i n construction. Stop #4-a) The rocks are quite large ( 1 5 cm) but smaller than those at Stop #2. They are mostly plutonic and metamorphic, d i o r i t e and gneiss, with some volcanic b a s a l t s . b) The r i v e r occupies about 2C$ of i t s entire bed. I t used to carry the most water i n June and the l e a s t i n February. The most water was produced when the winter snow-pack was melting, and the l e a s t when most p r e c i p i t a t i o n was i n the form of snow. c) The r i v e r i s (usually) not carrying much sediment, but more than was observed at Stop #2. Sediment would be added to the r i v e r by the gravel operations upstream. Drive to Stop # 5 a) The v a l l e y becomes wider and f l a t t e r as we t r a v e l downstream. b) Farming i s c a r r i e d on here because the s o i l i s exceptionally f e r t i l e . Stop # 5 a) The land surface i s c a l l e d a f l o o d p l a i n . b) An upstream dam, and dykes prevent f l o o d i n g . S o i l f e r t i l i t y must be maintained by adding f e r t i l i z e r s . c) The r i v e r i s meandering. I t flows slowly. d) The r i v e r usually c a r r i e s more sediment here than i t does further upstream. I t would be mostly f i n e sediment 2 3 3 because the water flows slowly. e) No d e l t a i s forming where the Coquitlam flows into the Fraser because the current i n the Fraser sweeps away the sediment before i t can be deposited. Part C b) The sand sample consists of l i g h t and dark p a r t i c l e about evenly mixed. The o r i g i n a t i n g rock was probably d i o r i t e or gneiss. e) During the l a s t i c e age, the v a l l e y of the Coquitlam was occupied by a g l a c i e r which widened and deepened a p r e - e x i s t i n g v a l l e y . As the g l a c i e r retreated, the meltwater deposited huge qu a n t i t i e s of sediment i n the v a l l e y . The present r i v e r has st a r t e d to excavate t h i s sediment and deposit i t further downstream i n the form of a fl o o d p l a i n . Construction of a dam and dykes has slowed the erosional and d e p o s i t i o n a l processes. 254-EQUIPMENT REQUIRED. Item Aquarium, 25 L with glass cover Asbestos gauze Beaker, P:/rex, 250 mL Bott l e , dropper Bunsen burner Dish, evaporating Dish, p e t r i (10 mm x 100 mm) F i l t e r paper, 12.5 cm Funnel, 65 mm diam., long stem Graduated cylinder,- 25 mL Hand lens Masking tape Microscope, stereoscopic Ring stand with 8 cm diam r i n g Stream table S t e e l wool Balance, centigram CHEMICALS REQUIRED Item Hydrochloric acid (cone.) P l a s t e r of Pa r i s SPECIMENS REQUIRED Item Rocks (hand size) Andesite Breccia Basalt Coal Quantity 1 1 per s t a t i o n 1 per s t a t i o n 1 1 per s t a t i o n 1 per s t a t i o n 2 per s t a t i o n 2 pkg. 1 per s t a t i o n 1 per s t a t i o n 1 per s t a t i o n 1 r o l l 1 per s t a t i o n (optional) 1 per s t a t i o n 1 per c l a s s • 1 pkg. 1 per s t a t i o n Quantity 1 L 1 kg Quantity 1 per c l a s s Conglomerate d i o r i t e 235 Gabbro Gneiss Limestone Marble Porphyry 'Pumice Rhyolite Sandstone Slate F o s s i l s ammonite brachiopod crinoid.stem gastropod Limestone, crushed ( 1 - 2 cm) Seeds, bean or corn Rock, g l a c i a l l y s t r i a t e d MAPS REQUIRED Item Topographic 92G/7 Coquitlam 92G Vancouver Geologic Granite Obsidian Quartzite Shale 1 per s t a t i o n horn c o r a l r e p t i l e bone lea f (broad) shark tooth le a f ( c o n i f e r ) t r i l o b i t e pelecypod 5 kg 1 pkg. 1 per class. Quantity 1 per s t a t i o n 1 per s t a t i o n 1 per s t a t i o n 1 per c l a s s 1 1 5 3 A Coquitlam 1253A G l a c i a l Map of Canada 1257A Retreat of Wisconsin and Recent Ice i n North America 1 per cla s s 236 RECOMMENDED AUDIO-VISUAL AIDS 16 mm fi l m s (Encyclopaedia B r i t a n n i c a Educational Corp.) 1 . Rocks that Form on the Earth's Surface (16 min). 2 . Rocks that Originate Underground ( 2 3 rain). 3 . The Beach - A River of Sand ( 2 0 min). 4. Erosion - L e v e l l i n g the Land (14 min). 5 . Why Do We S t i l l Have Mountains? ( 2 1 min). 6. Gla c i e r on the Move ( 1 1 min). 7 . Evidence f o r the Ice Age ( 1 9 min). 8 mm Film Loop (Walt Disney Corp.) Flas h Flood 3 5 mm colour s l i d e s (B.C. Teachers' Federation). 1 . Lesson Aid M-1 ( 1 0 5 Geology S l i d e s ) . 2 . Lesson Aid M - 5 1 ( 3 8 Athabaska G l a c i e r S l i d e s ) . 237 Teachers' Manual and Answer Key '- Part 2 238 INVESTIGATION 1 Objectives: After completing t h i s exercise, the student should be able to: a) Name and describe each of the layers of the Earth. b) Describe the r e l a t i v e thicknesses of the layers of the Earth. Equipment Required (per student) compass Teaching Suggestions Introduce t h i s exercise by asking the students what they think might be inside the Earth. Remind them of some clues such as d r i l l holes and volcanoes. For Procedure B, some students w i l l require assistance with s e t t i n g t h e i r compasses to scale distances. Answers to Procedure Questions A. Layer Lithosphere Asthenosphere Lower Mantle Outer Core Inner Core Thickness Depth of top (km) from surface (km) 160 560 2200 2250 1200 0 160 7 2 0 2920 4120 Distance of top from centre (km) 6 3 7 0 6210 5650 3 4 5 0 1 2 0 0 INVESTIGATION 2 Objective: Aft e r completing t h i s exercise, the student should be able to state a comparison between the thickness 2 3 9 of the lithosphere and the size of some surface structures on the Earth. Materials required 2 sheets of graph paper Teaching suggestions Some students w i l l require assistance with choosing a suitable scale f o r the v e r t i c a l axis on each bar graph. Answers to Questions 1. The crust i s approximately 1/40 of the Earth's radius. 2. Man-made features are small compared to the size of the Earth. 3 - The crust i s th i c k e r under the continents because o f the a d d i t i o n a l thickness of the continental rock. 4. D r i l l i n g a hole through the crust would be easier on the ocean bottom because the crust i s thinner there. 5* a) Pressure increases with depth. b) I t i s possible that the increased pressure squeezes the atoms together so that only the s o l i d phase w i l l form. NARRATIVE 5 Objectives: A f t e r reading t h i s n a r r a t i v e , the student should be able to: a) Describe the o r i g i n of the atmosphere. b) State the composition of the atmosphere. Teaching Suggestions This narrative provides the student with a number of f a c t s about the atmosphere. Emphasize the point that the atmosphere i s the outer layer of our planet. 240 To arouse i n t e r e s t , perform demonstrations with a b e l l j a r and vacuum pump to show what can happen i n the absence of an atmosphere. A mixture of ethanol and water w i l l b o i l very e f f e c t i v e l y when the pressure i s reduced, and a p a r t i a l l y i n f l a t e d balloon w i l l expand and burst. Answers to Questions 1 . The density of hydrogen and helium i s lower than that of nitrogen and oxygen, hence they tend to r i s e . NARRATIVE 4 Objective: Aft e r reading t h i s n a r r a t i v e , the student should be able to: a) Describe the o r i g i n of the Earth. b) Describe two theories accounting f o r the absence of surface rocks with the same age as the Earth. Teaching Suggestions I f p ossible, show a number of colour s l i d e s or pictures of astronomical objects purporting to show the o r i g i n of s t a r s . Answers to Questions 1 . I f the Earth had formed c l o s e r to the sun, the temperature would be higher, and as a r e s u l t there would probably be no oceans. L i f e forms would probably be d i f f e r e n t . 2. I f the Earth had formed between J u p i t e r and Saturn, i t would be much colder, and might have a very deep atmosphere of methane and ammonia, hydrogen and helium. 3. Volcanoes show that the i n t e r i o r of the Earth i s s t i l l hot. 241 INVESTIGATION 5 Objective: After completing t h i s exercise, the student should be able to state a comparison between the age of our planet and the age of l i f e upon i t . Materials required (per group) 5 m of paper tape ( t i c k e r tape) metre s t i c k Teaching suggestions Numbers alone can not give a f e e l i n g f o r the true extent of the age of the Earth. This exercise spreads t h i s l i f e out i n v i s u a l form. Point out to students that i n terms of the l i f e of the Earth, the age of dinosaurs was comparitively recent. Note the ridiculousness of cartoons showing cave-men and dinosaurs together. Answers to Questions 1 . a) Event Era Humans Cenozoic Land plants Paleozoic Rocky Mountains Mesozoic & Cenozoic Dinosaurs Mesozoic F i r s t Insects Paleozoic West Coast Mountains Mesozoic Last ice age Cenozoic F i r s t Animals Precambrian Formation of Earth- Precambrian 242 Cenozoic 7 0 m i l l i o n years Mesozoic 155 Paleozoic 375 Precambrian 4000 c) Cenozoic 1 . 5 * Mesozoic 3-4% Paleozoic 8.2* Precambrian . 86.9* 2 . 1 0 0 0 0 0 ge nerations have passed since the f i r s t recognizable humans appeared. 3 . a) Ear l y men never used dinosaurs f o r food. b) Dinosaurs became ext i n c t many m i l l i o n s of years before men evolved. NARRATIVE 6 Objectives: Aft e r reading t h i s n a r r a t i v e , the student should be able to: a) Describe h i s t o r i c a l attempts to measure the age of the Earth. b) Describe radiometric dating of rocks. Teaching Suggestions This narrative should be assigned only to those students with a good grasp of chemistry. Answers to Questions 1 . The rock i s approximately 400 m i l l i o n years o l d . 2 . The rock was approximately 4 . 5 b i l l i o n years o l d . 3 . The h a l f - l i f e of the potassium-argon decay process i s approximately 1 . 2 b i l l i o n years. 24-3 4-. In very young rocks the amount of material which . has decayed i s too small to be measureable. 5 . . a) The lava was 5730 years o l d . b) The leaf was 114-60 years old. 6. a) I f the rocks had been disturbed, the chemical . composition might have changed, and t h i s would produce i n c o r r e c t ages. b) The r e s u l t i n g age would be too young. 7. Joly would have had d i f f i c u l t y i n measuring the amount of s a l t added to the oceans each year. He assumed that t h i s rate had remained constant through the ages, and f a i l e d to account f o r s a l t dissolved from the ocean f l o o r . K e l v i n d i d not know the o r i g i n a l temperature of the Earth. He f a i l e d to account f o r heat added by radioactive decay within the Earth. INVESTIGATION 7 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Name and describe a number of f o s s i l s common i n western Canada. b) Explain several uses of f o s s i l s . Equipment Required (per group) Samples of the following f o s s i l s : t r i l o b i t e shark tooth ammonite c r i n o i d stem brachiopod pelecypod gastropod r e p t i l e bone angiosperm l e a f gymnosperm le a f s i l i c i f i e d wood carbonized wood 244 Teaching Suggestions . Although i t i s obviously better i f the students can work from actual specimens, Procedures A to J may be c a r r i e d out by using the photographs printed i n the text. During the exercise, emphasize both the i n t r i n s i c i n t e r e s t of the f o s s i l s themselves, and the a n c i l l a r y information such as climate and environment that may be gained from them. As well as the student specimens, i t i s sometimes useful to have larg e r , better q u a l i t y d i s p l a y specimens a v a i l a b l e . Loss of student specimens may be reduced by sealing them i n Riker mounts. The value of taking j u n i o r secondary students on an actual c o l l e c t i n g t r i p i s doubtful. Good f o s s i l l o c a l i t i e s can be destroyed by indiscriminate c o l l e c t i n g . Answers to Procedure Questions A. This procedure i s intended to introduce students to the most basic p a l e o n t o l o g i c a l question, "What i s i t ? " . The only specimen which may cause d i f f i c u l t y i s the c r i n o i d stem, which i s part of an animal. B. F l e x i b l e j o i n t s enable the animal to move more e a s i l y , or to r o l l up f o r protection of i t s sof t underside. The remainder of the animal probably rotted, or was eaten. T r i l o b i t e s became ext i n c t about 225 m i l l i o n years ago. Animals which may be descended from t r i l o b i t e s are the crab, l o b s t e r , shrimp, prawn, and c r a y f i s h . C. The shark tooth i s pointed whereas a human fr o n t tooth i s c h i s e l shaped. The human back tooth i s f l a t . The shark probably i s a meat eater, since i t s teeth are designed f o r 245 tearing f l e s h . Shark teeth are frequently the only part f o s s i l i z e d because they are one of the few hard parts of the animal. D. The octopus or squid may be r e l a t e d to the ammonites. F. The brachiopod s h e l l has upper and lower halves which are d i f f e r e n t . The two halves of a pelecypod s h e l l are symmetrical. G. Claras, s c a l l o p s , oysters, mussels and many other pelecypods are edible. H. Some gastropods are edible (escargots). The gastropod s h e l l i s c o i l e d c o n i c a l l y , whereas the ammonite s h e l l i s c o i l e d f l a t . I. The colour and weight of the bone show that i t has been p e t r i f i e d . I t s shape and the i n d i c a t i o n of marrow resemble modern bone. J . Unbroken f o s s i l leaves are rare because most leaves break up soon a f t e r f a l l i n g . Figure shows a s e l e c t i o n of leaves found i n a moist temperate climate today, s i m i l a r to the climate of the B r i t i s h Columbia coast. Coal i s formed when massive amounts of vegetation are f o s s i l i z e d i n t h i c k beds. K. Ring structure may show In good specimens of s i l i c i f i e d and carbonized wood. Answers to Questions 1. A f o s s i l i s preserved evidence of p r e h i s t o r i c l i f e . 2. a) t r i l o b i t e b) ammonite c) brachiopod d) c r i n o i d stem e) tracks 246 3. a) mould b) replacement c) cast d) carbonization 4. F o s s i l s are seldom found i n volcanic rocks because the heat usually destrys the specimen. However, specimens are frequently found buried i n ash, Pompeii being the most famous example. INVESTIGATION 9 Objectives: A f t e r completing t h i s exercise, the student should be able to: a) Ide n t i f y homologous structures i n d i f f e r e n t organisms. b) Explain the reasons f o r modifications i n the limbs of various organisms. Materials Required (per student) F u l l page copies of Figures 1.47 and 148. Coloured p e n c i l s Teaching Suggestions Introduce the exercise by asking students how they would decide whether or not d i f f e r e n t animals are r e l a t e d , f o r example monkey and g o r i l l a , dog and wolf. Keep st r e t c h i n g the point by introducing animals i n which the resemblance i s l e s s and l e s s obvious, such as moose and horse, mouse and elephant, b i r d and dog e t c . u n t i l a point i s reached where the students decide that there i s no r e l a t i o n s h i p at a l l between a p a i r of animals. Follow t h i s by introducing the comparison between e x t i n c t and modern animals and the idea of t r a c i n g l i n e s of descent. L a s t l y , introduce the s p e c i f i c s of comparing bone st r u c t u r e . 247 Answers to Procedure Questions . D. The plesiosaur limb has been modified i n t o a f l i p p e r f o r p r o p e l l i n g the animal through the water. The three-toes horse has developed a l i g h t , strong limb f o r speed when running. The pteranodon limb i s very l i g h t , with one d i g i t greatly extended to support the skin of the wing. Like the plesiosaur, the seal forelimb i s a f l i p p e r designed f o r propulsion i n water, but i t also has the strength to support the seal on land. The bat limb i s l i g h t and strong to support the wing without excessive weight. The sabretooth t i g e r limb i s heavy and strong f o r speed and k i l l i n g a b i l i t y . Answers to Questions 1 . Animal Environment Camel Desert Whale Ocean Mountain sheep Mountains Monkey Forest or jungle Mole Underground Eagle A i r 2. Animal Reason Camel Do not sink i n s o f t sand Whale P r o p e l l i n g animal through water Mountain sheep "Suction" e f f e c t to grip rock Monkey Add i t i o n a l limb to grasp branches Mole Digging .Eagle G l i d i n g e a s i l y 248 NARRATIVE 9 Objectives: Aft e r reading t h i s narrative, the student should be able to: a) Describe M i l l e r ' s attempt to show how l i f e began on Earth. b) Describe i n general terms the h i s t o r y of l i f e . c) Describe evolutionary theory i n terms of s u r v i v a l of the f i t t e s t . d) Describe the o r i g i n and development of humans.. Teaching Suggestions Refer back to Investigations 5 and 7 , pointing out that f o s s i l s and radiometric dating are our only sources of information f o r t h i s h i s t o r y . Answers to Questions 1. A species l i v e s where competition f o r food i s l e a s t . 2. A species w i l l survive i f i t can f i n d a space to l i v e where i t can compete s u c c e s s f u l l y f o r food, and reproduce i t s e l f . I f another species meets these c r i t e r i a more su c c e s s f u l l y i n that p a r t i c u l a r l i v i n g space, i . e . i s " f i t t e r " , then i t w i l l survive while the other must e i t h e r adapt to compete more s u c c e s s f u l l y or become e x t i n c t . NARRATIVE 10 ' Objective: After reading t h i s n a r r a t i v e , the student should be able two describe two a l t e r n a t i v e theories about the o r i g i n and development of the Earth. Teaching Suggestions I t should be quite c l e a r that t h i s course i s strongly 24-9 biased i n favour of evolutionary theory. This narrative may be assigned f o r information only, or used as a basis f o r class debate. Teachers should be wary of offending students' or parents' r e l i g i o u s b e l i e f s . INVESTIGATION 11 Objectives: A f t e r completing t h i s exercise, the student should be able to: a) Explain how sedimentary rocks are formed. b) I d e n t i f y and name a number of common sedimentary rocks. Equipment Required per group: 250 mL beaker 600 mL beaker metre s t i c k platform balance per class: mixture of sand and s i l t , l o c a l geologic map clean dry sand 1M HC1 i n dropper b o t t l e samples of: shale, sandstone, conglomerate, breccia, h a l i t e , massive limestone, f o s s i l i f e r o u s limestone, dolomite, chert, and c o a l . Teaching Suggestions . Emphasize o r i g i n of sedimentary rocks, rather than i d e n t i f i c a t i o n . Answers to Procedure Questions A. The sand s e t t l e s f i r s t . The material s e t t l e s i n l a y e r s . B. Layering i s the most noticeable feature of these rocks. F. The student can not state whether or not the weight i s s u f f i c i e n t to squeeze sediment in t o rock, however, the number of grams involved i s impressively l a r g e . 250 Answers to Questions 1. Water Speed Type of Sediment Carried Name of Rock Formed Fast Pebbles, sand, s i l t Conglomerate Medium Sand, s i l t Sandstone Slow s i l t Shale 2. Conglomerate would form at A, sandstone at B, and shale at C. 5. H a l i t e would probably form i n a hot, dry climate which would aid evaporation. INVESTIGATION 12 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Define the term "geothermal gradient" b) Present evidence that the i n t e r i o r of the Earth i s hot. c) Relate the geothermal gradient to the depth at which magma w i l l form. Materials Required 2 sheets graph paper. Teaching Suggestions; This exercise should be considered supplementary to the basic course. A l l students w i l l agree that volcanism shows the i n t e r i o r of the Earth to be hot. This i n v e s t i g a t i o n extends t h i s observation q u a n t i t a t i v e l y . Answers to Procedure Questions A. Most students w i l l present volcanism as a t h i r d example showing that the I n t e r i o r of the Earth i s hot. 251 D. Icelandic geothermal gradient i s approximately 62°C/km. South A f r i c a n figure i s about 11°C/km. E. The estimated temperature at a depth of 10 km i s 620°C i n Iceland and 110°G i n South A f r i c a . J . Granite would melt at approximately 12 km beneath Iceland, and 60 km beneath South A f r i c a . Basalt would melt about 18 km beneath Iceland. Volcanoes would be more common i n Iceland. Answers to Questions 1. Volcanoes, hotsprings and geysers show that the i n t e r i o r of the Earth i s hot. 2. a) The estimated temperature would be 394 320°C at the centre of the Earth. b) Compared to the temperature of the sun, t h i s r e s u l t seems to be unreasonable. c) I f the temperature increased a l l the way to the centre of the Earth, the r e s u l t i n g temperature there i s impossibly high. 3. a) South A f r i c a ' s climate i s generally warmer than Iceland's. b) Iceland has a ihgher geothermal gradient than South A f r i c a . c) I f the heat within the Earth were caused by heat from the sun, then the geothermal gradient i n South A f r i c a would be higher than that i n Iceland. NARRATIVE 1 3 Objective: Aft e r reading t h i s n a r r a t i v e , the student should be able to describe how us e f u l energy may be extracted 2 5 2 from geothermal heat. Teaching Suggestions Relate t h i s narrative to newspaper a r t i c l e s which p e r i o d i c a l l y describe geothermal development i n western Canada. Answers to Questions 1. The presence of volcanoes in d i c a t e s high temperatures close to the surface of the Earth. This means that the p o t e n t i a l f o r geothermal steam or water i s much greater. 2 . Subsurface temperatures i n Iceland are so hot that the p o s s i b i l i t y of geothermal water being present i s extremely high. INVESTIGATION 14 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Describe a volcano as a cinder cone, s h i e l d cone or stratovolcano. b) Explain the r e l a t i o n s h i p between volcanic form and the c h a r a c t e r i s t i c s of the lav a which produced i t . c) Describe and name a number of t y p i c a l volcanic landforms. Equipment Required 2 - 2 5 0 mL beakers 600 mL beaker mixture of sand and small pebbles sand wax r i n g stand and r i n g bunsen burner cardboard sheet Teaching Suggestions Volcanoes are always a high i n t e r e s t subject. I l l u s t r a t e 2.53 with some of the many good f i l m s and s l i d e s a v a i l a b l e . I f possible, have the students keep a "volcano watch" with a world map and newspaper or t e l e v i s i o n reports. Answers to Procedure Questions B. A cinder cone i s small with f a i r l y steep sides. A s h i e l d volcano i s large with long sloping sides. A s t r a t o -volcano i s large with gentle slopes at the base, and steep slopes near the summit. C. The sides of the cone are steep. A cinder cone i s formed by the eruption of s o l i d , lumpy pieces of rock. D. The sides of the model volcano are gently sloping. A s h i e l d volcano i s formed by the eruption of l i q u i d l a v a . Answers to Questions 1. Figure 1 5 9 i s a s h i e l d Figure 165 i s a s h i e l d 160 s h i e l d 164 s h i e l d 161 stratovolcano 165 stratovolcano 162 cinder cone 166 cinder cone 2. Figure 167 i s a caldera Figure 170 shows columns 168 dyke 171 black sand 169 lava tube 3- The landform being produced could be e i t h e r a dyke or a lava plateau ( f l o o d l a v a ) . 4. Magma i s molten rock underground. Lava i s magma which has reached the surface. 5. a) This landform i s a f l o o d l a v a . 2 b) The area covered i s approximately 120 000 km . 6. a) Olympus Mons i s a s h i e l d volcano. p b) Olympus Mons covers an area of about 450 000 km . 254 c) The depression at the summit of Olympus Mons i s a caldera. 7. a) Pressure of magma pushing up beneath a volcano could cause i t to swell. b) Huge masses of molten rock moving beneath a volcano could cause small earthquakes. c) S c i e n t i s t s could p r e d i c t eruptions by measuring the swelling of a volcano, or detecting small earthquakes i n i t s v i c i n i t y . INVESTIGATION 15 Objective: A f t e r completing t h i s exercise, the student should be able to describe the pattern formed by the locations of volcanoes. Materials Required world map, North America centred Teaching Suggestions This exercise could be accompanied by a 'Volcano watch", whereby students p l o t the lo c a t i o n s of volcanic eruptions reported by newspapers and t e l e v i s i o n . Answers to Questions 1. The P a c i f i c Ocean i s surrounded by volcanoes. 2. The A t l a n t i c Ocean has a l i n e of volcanoes down i t s centre. This chain i s c a l l e d the Mid-Atlantic Ridge. 5. a) The Earth's crust i s t h i c k e r under the continents. b) Magma i s probably nearer the surface under an ocean. c) Perhaps the crust i n the centres of continents i s too t h i c k to allow magma to reach the surface. 2 5 5 NARRATIVE 16 Objective: After reading t h i s narrative, the student should be able to describe the c h a r a c t e r i s t i c s of a number of volcanoes i n and near B r i t i s h Columbia. Teaching Suggestions Some students may have hiked or skied i n the areas mentioned. They may be able to provide s l i d e s or photo-graphs. Reports of a c t i v i t y on Mount Baker appear i n the newspapers from time to time. Answers to Questions 1. Eve Cone i s a cinder cone. 2 . Mount Edziza i s f a r away from present centres of population and energy usage. Construction of power l i n e s would be expensive and d i f f i c u l t . 4. Vancouver could be endangered by an eruption of Mount Baker i f an easterly wind were to carry ash towards the c i t y . I t i s u n l i k e l y that lava or mudflows would endanger Vancouver because of the distance involved and the h i l l y ground over which they would have to t r a v e l . INVESTIGATION 17 Objectives: Aft e r completing t h i s exercise, the student should be able to: a) Describe the o r i g i n of igneous and metamorphic rocks. b) I d e n t i f y a number of igneous and metamorphic rocks. Equipment Required hand lens or stereo microscope 256 Materials Required samples of: granite quartz d i o r i t e gabbro r h y o l i t e andesite basalt obsidian pumice porphyry gneiss marble sl a t e quartzite Answers to Procedure Questions A. Igneous rock contains c r y s t a l s . Sedimentary rocks seldom contain these. o B. The c r y s t a l s are generally large enough to be seen without C. Usually a hand lens or microscope i s required i n order to see the c r y s t a l s i n volcanic rock. E. The clue w i l l depend upon the sample examined. Generally i t w i l l involve the lack of l a y e r i n g , or the presence of banding. Answers to Questions 1. a) Plutonic rocks are formed deep underground. b) For plutonic rocks to be exposed, the overlying rocks must be eroded. 2. a) Slow cooling causes the formation of large c r y s t a l s , b) Rocks underground cool more slowly because they are insulated by the overlying rock. 3. Gas bubbles i n the o r i g i n a l lava form hubbies i n pumice. 4-. Obsidian cools very r a p i d l y . 5. Andesite i s named f o r the Andes Mountains. a microscope. 2 5 7 NARRATIVE 18 .. Objective: After reading t h i s narrative, the student should be able to describe the rock c y c l e . Teaching Suggestions Many students tend to think of the surface of the Earth as unchanging. Point out that some changes occur so slowly that they are very d i f f i c u l t to see i n a single l i f e t i m e . The rock cycle i s one of these. Answers to Questions 1. Igneous rock can be eroded. The r e s u l t i n g sediment may be washed into an ocean where pressure eventually turns i t into sedimentary rock. 2 . Igneous rock may be heated and squeezed by volcanic action, thereby turning i t to metamorphic rock. 3. Plutonic rock could be melted, and the r e s u l t i n g magma forced to the surface of the Earth as lav a . NARRATIVE 19 Objective: Aft e r completing t h i s exercise, the student should be able to: a) Describe the causes of earthquakes b) Describe the Richter and M e r c a l l i scales, and explain the differences between them. c) Define the areas of high and low earthquake r i s k i n Canada. Teaching Suggestions Many students or t h e i r parents have experienced earthquakes. Try to obtain d e s c r i p t i o n s from these people. 258 Answers to Questions 1 . The focus i s the place where the rock a c t u a l l y breaks. The epicentre i s the point on the surface of the Earth d i r e c t l y above the focus. 2 . The Richter magnitude measures only one thing, energy released by the earthquake. The M e r c a l l i i n t e n s i t y changes with distance from the epicentre. 3 . Figure 154 shows M e r c a l l i i n t e n s i t y VII. Figure 155 shows i n t e n s i t y X. 5 - These c i t i e s are found i n the following earthquake hazard zones: Vancouver - 3 , Prince Rupert - 3 , Calgary - 0 , Winnipeg - 0 , Toronto - 1 , Ottawa - 2 , Quebec C i t y - 3 , H a l i f a x - 1 , St. John's - 2 . INVESTIGATION 20 Objective: Aft e r completing t h i s exercise the student should be able to explain the p r i n c i p l e s upon which a seismograph works. Equipment Required 'model seismograph Teaching Suggestions Before s t a r t i n g t h i s exercise, t r y to show at l e a s t one f i l m about earthquakes. Most of these f i l m s have sequences showing seismographs operating. Use these sequences as an intr o d u c t i o n to t h i s i n v e s t i g a t i o n . Model seismographs are notoriously d i f f i c u l t to operate. Unless you have an unusually capable c l a s s , i t might be better to perform t h i s i n v e s t i g a t i o n as a demonstration. 259 Answers to Procedure Questions A. When pulled slowly, the paper causes the book to move. If the paper i s given a quick jerk, the book w i l l not move. B. The penholder has i n e r t i a , and re s i s t s , moving at f i r s t . - The table moves underneath the pen. C. When no earthquake i s happening, the seismograph records a s t r a i g h t l i n e . -D. During a small earthquake, the seismograph records a l i n e with small "wiggles". E. During a strong earthquake, the seismograph records a l i n e with v i o l e n t "wiggles". Answers to Questions 1. a) I n e r t i a i s resistance to rap i d changes i n motion, b) A seismograph uses i n e r t i a to hold the pen s t i l l , while the earth moves beneath i t . 2. To record back and f o r t h motion, rotate the p o s i t i o n of the seismograph 90°. 3. Try mounting the seismograph on springs, while the paper i s s t i l l attached to the ground. INVESTIGATION 21 Objective: A f t e r completing t h i s exercise, the student should be able to use seismograms to locate the epicentre of an earthquake. Materials Required 2 c o i l springs ( s l i n k y ) f u l l page copy of Figure 80 260 Teaching Suggestions Despite a f i r s t impression of d i f f i c u l t y , most students can be taught how to use seismograms to locate the epicentre of an earthquake. The point to be stressed i s that t h i s i s one of the f i r s t steps i n analysing an earthquake that " r e a l " s c i e n t i s t s carry out at the P a c i f i c Geoscience Centre. Of course, t h e i r studies go much further, but the i n i t i a l steps can be learned quite e a s i l y by a student i n Grade 10. Answers to Procedure Questions A. The compression t r a v e l s down the length of the spring. Each c o i l moves back and f o r t h i n the same d i r e c t i o n as the spring. Each c o i l causes the next to move by pushing upon i t , then rebounding to i t s o r i g i n a l p o s i t i o n . C . The wave t r a v e l s down the length of the spring. Each c o i l moves sideways across the spring. Each c o i l causes the next one to move by dragging i t sideways, then rebounding to i t s o r i g i n a l p o s i t i o n . E. The P-wave t r a v e l s f a s t e r , and a r r i v e s at the other end of the spring f i r s t . F. The enti r e trace i s 53 seconds long. G. The strongest waves were recorded at Port Alberni at 02h 48m 45.8s. I to 0. Station P-wave S-wave Travel time Distance V i c t o r i a 48m34.3s 48m44.0s 9 . 7 s 85 km Port Alberni 48m35.5s 48m45.6s 10.1s 89 km Haney 48m33.9s. 48m43.0s 9 . 1 s 81 km 261 0. The earthquake's epicentre was located i n the middle of the S t r a i t of Georgia, on almost a d i r e c t l i n e between Haney and Port A l b e r n i . Answers to Questions 1. a) An earthquake i n Vancouver would probably cause more damage and i n j u r y than-one at Williams Lake. b) An earthquake at 2:00 p.m. Tuesday would probably cause more i n j u r y than one at 7:00 a.m. Sunday. 2. An earthquake occurring i n a large c i t y when many people are congested into a small number of crowded buildings would probably cause more destruction than an earthquake occurring i n a r u r a l area when people are at home, spread out into a large number of small b u i l d i n g s . 3. This earthquake was located i n the P a c i f i c Ocean, j u s t west of the S t r a i t of Juan de Fuca. 4. This earthquake was located i n the U.S.A., south of Haney. INVESTIGATION 22 Objectives: A f t e r completing t h i s exercise, the student should be able to describe the l o c a t i o n s of major f a u l t zones i n B r i t i s h Columbia and around the world. Materials Required f u l l page copies of Figures 183 and 184 Teaching Suggestions Stress the point that s c i e n t i s t s do not locate earth-quakes just f o r the sake of l o c a t i n g earthquakes. They look f o r a pattern i n order to p r e d i c t where earthquakes are l i k e l y to occur i n the fu t u r e . 262 Answers to Procedure Questions C. Seattle i s subject to earthquake hazard. Answers to Questions 1. Earthquakes seem to occur more i n some areas than i n others. 2. The earthquake zones are s i m i l a r to the volcano zones. 3. a) This i s a matter f o r debate. INVESTIGATION 24 Objective: Aft e r completing t h i s exercise, the student should be able to describe the topography of the f l o o r of the North A t l a n t i c Ocean. Materials Required one sheet of millimetre graph paper Teaching Suggestions Many students have the mistaken idea that the sea f l o o r i s f l a t and f e a t u r e l e s s . Use t h i s exercise to convince them otherwise. Point out that as we continue to use up the resources- of the land, we must l e a r n more about the seas i f our c i v i l i z a t i o n i s to continue to t h r i v e . Answers to Procedure Questions A. The ocean f l o o r i s mountainous. The mountains are generally located i n the centre of the ocean, while the deep f l a t areas are located along t h e i r edges. The shallow f l a t areas are located along the edges of continents. P. The shape of the A t l a n t i c Ocean f l o o r i s generally symmetrical. 263 Answers to Questions 1. The Mid-Atlantic Ridge i s about 16 000 km long. 2. Most r i v e r sediment i s deposited on the continental s h e l f . 3. S c i e n t i s t s might obtain rock samples from the ocean f l o o r by using a submarine or a ship mounted d r i l l . NARRATIVE 25 Objective: After reading t h i s n a r r a t i v e , the student should be able to describe some of the evidence used by A l f r e d Wegener to support the theory of continental d r i f t . Teaching Suggestions Stress again that geologic processes can happen so slowly that they are not d i s c e r n i b l e i n a human l i f e t i m e . Answers to Questions 1. Evidence of c i t i e s dredged from the ocean f l o o r would probably s u f f i c e . INVESTIGATION 26 Objective: A f t e r completing t h i s exercise, the student should be able to describe the accuracy of the jigsaw f i t of the continents bordering on the A t l a n t i c Ocean. Materials Required (per student) F u l l page copies of Figures 187 and 188 2 sheets of 1 cm graph paper glue s c i s s o r s Teaching Suggestions Warn the students that they sould keep the continents i n the same r e l a t i v e p o s i t i o n s that they occupy today. Answers to Procedure Questions D. The edges of the continental shelves provide, a better f i t 264-than the edges at present day sea l e v e l . A supporter of the theory of continental d r i f t would choose the edge of the continental shelf as the "true" edge of the continent. Answers to Questions 1. The apparent symmetry of the continental edges made s c i e n t i s t s think that these continents might once have been joined. 2. Discovery of the continental shelves supported t h i s theory by providing a better f i t . 3. a) During the i c e age, the sea l e v e l was lower than i t i s today. b) There i s no reason why the present sea l e v e l should be considered the true edge of the continents. 4-. a) The Mid-Atlantic Ridge runs down the centre of the A t l a n t i c Ocean. b) These mountains are volcanic rock. c) Lava i s f i l l i n g the gap. INVESTIGATION 27 Objectives: A f t e r completing t h i s exercise, the student should be able to: a) Describe how the Earth's magnetic f i e l d can be recorded i n rock. b) Describe the magnetic pattern recorded on. the f l o o r of the A t l a n t i c Ocean. c) Describe how t h i s magnetic pattern supports the theory of continental d r i f t . 265 Materials Required (per class) set of compasses 5 boxes 5 bar magnets 10 f i l e cards set of f u l l page copies of F i g . 1 Teaching Suggestions For demonstration purposes, place one bar magnet i n each box, taped i n t o p o s i t i o n . P i l e the boxes one on top of the next so that the magnetic p o l a r i t i e s alternate. Before presenting the demonstration to the c l a s s , test i t y o urself. Answers to Procedure Questions B. Over long periods of time, the d i r e c t i o n of the Earth's magnetic poles, has reversed. C. Reversal of the magnetic poles may have occurred between deposition of successive layers of l a v a . E. The youngest rocks are located close to the centre of the pattern. The oldest rocks are located at the edges of the pattern. If the processes of ocean f l o o r spreading and magnetic r e v e r s a l continue, the pattern w i l l look s i m i l a r , but wider. G. The Mid-Atlantic Ridge i s located along the l i n e of present day rock. Farther from the ridge, the rocks are older. The rock at s t a t i o n 31 i s younger than 8 m i l l i o n years. At s t a t i o n 28 - older, s t a t i o n 15 - younger, s t a t i o n 2 5 - older than 8 m i l l i o n years. The ocean f l o o r i s moving outwards at 90° to the Mid-Atlantic Ridge. H. The distance from the ridge to one set of 8 m i l l i o n year old rocks i s approximately 80 km, or 80 000 000 cm. The ocean f l o o r i s moving at approximately 1 cm per year. 266 The ocean f l o o r i s spreading at 2 cm per year. In 90 years, the ocean w i l l be about 180 cm wider. Answers to Questions 1. I f Europe and North America were once joined, the pattern of magnetic re v e r s a l s should continue to the edge of the continental s h e l f . 2. The patterns match because they were formed i n the same place at the, same time, then spread apart. 3. The patterns match because they formed i n the same place at the same time, then spread apart. 4. a) I t i s approximately 3400 km from Canada to Europe, b) This c a l c u l a t i o n shows a time of 170 000 000 years since Canada and Europe s p l i t apart. NARRATIVE 28 Objective: After reading t h i s n a r r a t i v e , the student should be able to describe how the phenomenon of "polar wandering" supports the theory of continental d r i f t . Teaching Suggestions This narrative should be used as supplementary reading f o r the more able students.. NARRATIVE 29 Objective: A f t e r reading t h i s n a r r a t i v e , the student should be able to: a) Describe the causes of plate movement b) Describe the types of landforms produced at plate boundaries. 267 Teaching Suggestions This narrative may be used not only as a discussion of plate tectonic theory, but as an example of how s c i e n t i f i c theories are modified as new evidence becomes a v a i l a b l e . Answers to Questions 1. The s i x largest plates are the P a c i f i c , American, A f r i c a n , Eurasian, Indian - A u s t r a l i a n , and Antarctic p l a t e s . 2. The Nazca plate i s separating from the P a c i f i c plate along the East P a c i f i c Ridge. 3. The P a c i f i c plate i s subducting beneath the P h i l l i p i n e plate along the Marianas trench. 4. Many volcanoes are found i n Iceland because i t i s located on the Mid-Atlantic Ridge where magma i s pushing two plates apart. 5. The Arabian and the Eurasian p l a t e s caused the 1978 earthquake i n Iran. 6. The Queen Charlotte f a u l t l i e s between the P a c i f i c and the American p l a t e s . INVESTIGATION 30 Objectives: A f t e r completing t h i s exercise, the student should be able to describe how earthquakes may be used to determine a plate boundary. Equipment Required World Seismicity Map Copy of Figure 198 (per student) Teaching Suggestions , The World Seismicity Map may be obtained from the U.S. Geologic Survey at a cost of $1.50. 268 Answers t o Procedure Questions A. The dots represent earthquakes of magnitude 4 . 5 to 8 . 0 during the years July 1 9 6 5 to December 1 9 7 2 . The c i r c l e s represent earthquakes of magnitude greater than 8 . 0 during the years - 1 8 9 7 to 1 9 7 2 . B. Red represents shallow earthquakes, green intermediate, and blue deep. C. Figure 197 represents the Mid-Atlantic Ridge, and Figure 1 9 5 represents the Himalaya fountains. E. Inland from the coast, the earthquakes become deeper. Figure 196 best shows what i s happening i n South America. Here, the Nazca plate i s being subducted beneath the American plate, pushing up the Andes M o u n t a i n s . Answers to Questions 1 . Subduction on the west coast of South America i s taking place along the Peru - Chi l e Trench. 2 . When t h i s magma f i n d s i t s way to the surface, i t produces a volcano. 5 . Students have no basis f o r a "correct" answer to t h i s question. The best compromise would be a combination of fi g u r e s 1 9 4 and 1 9 6 NARRATIVE 51 Objective: A f t e r reading t h i s n a r r a t i v e , the student should be able to describe p l a t e movement along the San Andreas F a u l t . Teaching Suggestions Many students w i l l have already heard o f the San 269 Andreas F a u l t . This narrative gives them some f a c t u a l material upon which discussion may be based. Use the narrative to r a i s e the question of whether or not people should be allowed to l i v e i n earthquake zones. Answers to Questions 1. A l l answers are highly speculative, and subject to personal opinion. NARRATIVE 52 Objective: A f t e r reading t h i s n a r r a t i v e , the student should be able to describe plate movement near B r i t i s h Columbia, and use i t to explain a number of coastal landforms. Teaching Suggestions A l l the information contained i n t h i s narrative i s of f a i r l y recent o r i g i n . As research continues, some d e t a i l s may change. Use t h i s to point out what earth s c i e n t i s t s are doing i n B r i t i s h Columbia r i g h t now. Answers to Q u e s t i o n s 1. The c o l l i s i o n between a block of land on the P a c i f i c p l a t e , and the staionary American plate could cause mountains to be pushed up. 2. a) A plate subducting r a p i d l y would produce more magma than one subducting slowly. b) Since the Juan de Fuca plate i s subducting more r a p i d l y and thus producing more magma than the Explorer p l a t e , the volcanoes above i t should be more a c t i v e . 270 NARRATIVE 55 Objective: A f t e r reading t h i s narrative, the student should be able to describe the importance of mining to B r i t i s h Columbia. Teaching Suggestions I f you l i v e i n an area where mining i s of p a r t i c u l a r importance, t h i s narrative could be used as a s t a r t i n g point f o r a study of t h i s f a c e t of community l i f e . INVESTIGATION 54 Objective: Aft e r completing t h i s exercise, the student should be able to perform the common f i e l d i d e n t i f i c a t i o n t e s t s upon mineral specimens. Equipment Required (per c l a s s ) streak plates glass p l a t e s knives s t e e l f i l e s samples of: sulphur, garnet, magnetite, chromite, hematite, chalcopyrite, quartz (massive), limonite, feldspar, f l u o r i t e , t a l c , galena, b a r i t e , p y r r h o t i t e , c a l c i t e ( c r y s t a l ) , mica, gypsum, p y r i t e , quartz c r y s t a l , p y r i t e c r y s t a l , galena c r y s t a l , tourmaline c r y s t a l , skutterudite, molybdenite. Teaching Suggestions This exercise i s best set up as a number of " s t a t i o n s " . through which the student progresses. The number of st a t i o n s and hence the number of specimens required w i l l depend upon the i n d i v i d u a l preference of the teacher. Most specimens, with the exceptions of sulphur, c a l c i t e c r y s t a l , and p y r i t e c r y s t a l are i n the Prospectors Set of Minerals, a v a i l a b l e f o r a n o m i n a l c h a r g e f r o m t h e G e o l o g i c S u r v e y o f C a n a d a . A n s w e r s t o P r o c e d u r e Q u e s t i o n s R e f e r t o a n y g o o d r e f e r e n c e b o o k o n r o c k s a n d m i n e r a l s . S p e c i f i c a n s w e r s d e p e n d u p o n t h e e x a c t s p e c i m e n t e s t e d . A n s w e r s t o Q u e s t i o n s 1. A m i n e r a l i s a n a t u r a l l y o c c u r r i n g e l e m e n t o r c o m p o u n d . 2. a ) G r a n i t e i s m a d e u p o f a n u m b e r o f m i n e r a l s , b ) A r o c k i s a m i x t u r e o f m i n e r a l c r y s t a l s . 3. C o l o u r i s t h e s h a d e o f a b u l k y p i e c e o f m i n e r a l . S t r e a k i s t h e s h a d e o f a t h i n l a y e r o f p o w d e r e d m i n e r a l . 272 EQUIPMENT REQUIRED Item Asbestos gauze Beaker, pyrex, 250 mL Beaker, pyrex, 600 mL Box, cardboard, small Burner, bunsen Cardboard, sheet Compass, geometric Compass, magnetic Dropper bot t l e F i l e cards Glass plate, 10 cm square Graph paper, 1 cm Hand lens (or stereo microscope) Knife Magnet, bar Metre s t i c k Paper tape ( t i c k e r tape) Platform balance Ring stand with r i n g Seismograph model Slinky ( c o i l spring) Steel f i l e Streak plate Coloured p e n c i l s Quantity 1 per class 1 per group 1 per group 5 per class 1 per cl a s s 1 per c l a s s 1 per group 1 per group 2 10 1 per group 1 per group 1 per group 5 per cl a s s 1 per group 1 r o l l per c l a s s 1 per group 1 per cl a s s 1 per cl a s s 1 per group 1 per group 1 per group 1 set per group 2 7 3 CHEMICALS REQUIRED Item Hydrochloric Acid (cone.) Pebbles (pea size) Sand S i l t Quantity 1 L 2 kg 2 kg 2 kg SPECIMENS REQUIRED Item F o s s i l s Ammonite - Angiosperm l e a f Brachiopod C r i n o i d Stem Rocks (hand size) Andesite Basalt Breccia Chert Coal Conglomerate Dolomite Gabbro Minerals (thumb size) - Bar l t e ". C a l c i t e ( c r y s t a l ) Chalcopyrite Chromite Carbonized wood Gastropod Gymnosperm le a f Pelecypod Gneiss Granite H a l i t e Limestone (foss.) Limestone (mass.) Marble Obsidian Porphyry Feldspar F l u o r i t e Galena Galena g r y s t a l Quantity 1 per group Rep t i l e bone S i l i c i f i e d wood Shark tooth T r i l o b i t e 1 per c l a s s Pumice Quartz d i o r i t e Quartzite Rhyolite Sandstone Shale Slate 1 per group Garnet Gypsum Hematite Limonite Magnetite Mica Molybdenite P y r i t e 2?4 P y r i t e c r y s t a l Pyrrhotite Quartz c r y s t a l Quartz (massive) Skutterudite Sulphur Talc Tourmaline c r y s t a l MAPS REQUIRED Item Quantity A t l a n t i c Ocean Floor (Nat. Geog.Soc.) 1 per group World Seismicity Map (U.S. Geol. Survey) 1 per group . 2 7 5 RECOMMENDED AUDIO-VISUAL AIDS 16 mm Films (Encyclopedia B r i t a n n i c a Educ. Corp.) 1. Earth i n Change 2 . Earthquakes: Lesson of a Disa s t e r 3. Heartbeat of a Volcano 4. Rock that Originates Underground 5 . Rocks that Form on the Earth's Surface 6. San Andreas Fault 7. Volcanic Landscapes 8. Volcanoes: Exploring the Restless Earth 9. Why Do We S t i l l Have Mountains? 16 mm Film (National Film Board of Canada) 1. Face of the Earth 16 mm Film (Moonlight Productions) 1. F i r e Under the Sea 55 mm Colour S l i d e s (B.C. Teachers Federation) 1. Lesson Aid M-1 ; (103 Geology s l i d e s ) 276 BIBLIOGRAPHY 2 7 7 Akrigg, G.P.V. & Akrigg, Helen, B r i t i s h Columbia Chronicle -1778-184-6, Discovery Press, V i c t o r i a , B.C., 1 9 7 5 . Akrigg, G.P.V. & Akrigg, Helen, B r i t i s h Columbia Chronicle  184-7-1871, Discovery Press, V i c t o r i a , B.C., 1 9 7 7 . Anastasiou, C l i f f o r d J . , Forster, Mary, & Woodrow, Janice, Reading About Science 1, Holt Rinehart Winston of Canada, 1968. Anderson, Don L., The San Andreas Fault, S c i e n t i f i c American, V o l . 225, No. 5, pp. 52-68, 1 9 7 1 . Anderson, Frank W., The Frank S l i d e Story, F r o n t i e r Publishing,. Alder grove, B.C., 1968. Armstrong, Ken, Earth Science, Ideas f o r Projects, Adventures i n Earth Science Series No. 2, Department of Geology, U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 1 9 7 5 * Barghoorn, Elso S., The Oldest F o s s i l s , S c i e n t i f i c American, V o l . 224-, No. 5, pp. 50-42, 1 9 7 1 . Beck, Meryl, et a l , Which Way is_North?, Journal of Geological Education, V o l . 25, No. 5, pp. 141-145, 1 9 7 7 . Beerbower, James R., F i e l d Guide to F o s s i l s , Earth Science Curriculum Project Pamphlet Series PS-4, Houghton M i f f l i n , Boston, 1 9 7 1 . Blackadar, R.G., & Vincent, L.E., Focus on Canadian Landscapes, Miscellaneous Report No. 19, Geological Survey of Canada, Ottawa, 1 9 7 3 . Bloom, Arthur L., The Surface of the Earth, Prentice H a l l , New Jersey, 1969. ~~ ~ Blunden, R.H., H i s t o r i c a l Geology of the Lower Fraser River  Valley, Adventures i n Earth Science Series No. 5, Department of Geology, U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 1975* Boyer, Robert E., F i e l d Guide to Rock Weathering, Earth Science Curriculum Project Pamphlet Series PS-1, Houghton M i f f l i n , Boston, 1 9 7 1 . B r i t i s h Columbia Department of Mines and Petroleum Resources, The I d e n t i f i c a t i o n of Common Rocks, V i c t o r i a , B.C., 1968. 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B r i t i s h Columbia, B u l l e t i n No. 52, Geological Survey of Canada, Ottawa, ^ 5 9 • Washburn, Sherwood L., The Evolution of Man, S c i e n t i f i c American, V o l . 239, No. 3, pp. 194-208, 1978. Water Survey of Canada, Sediment Data, Canadian Rivers 1976, Inland Waters Directorate, Water Resources Branch,. Environment Canada, 1978a. Water Survey of Canada, H i s t o r i c a l Sediment Summary, B r i t i s h Columbia to 1976, Inland Waters Directorate, Water Resources Branch, Environment Canada, 1978b. Water Survey of Canada, H i s t o r i c a l Streamflow Summary, B r i t i s h Columbia to 1976, Inland Waters Directorate, Water Resources Branch, F i s h e r i e s and. Environment Canada, 1978c. Wetmiller, R.J., Canadian Earthquakes 1 9 7 5 , Seismological Series No. 7 7 , Seismological Service of Canada, Ottawa, 1 9 7 7 -White, Peter T., The Eternal Treasure, Gold, National Geographic, Vol. 145, No. 1, pp. 1 - 5 1 , 1974. Whitten, D.G.A., & Brooks, J.R.V., Penguin Dictionary of  Geology, Penguin, Harmondsworth, Englandj 1 9 7 2 . Williams, David J.R., A Proposal f o r the Development and Implementation of an Earth Science 1 1 Course f o r B.C.  High Schools, unpublished M.Ed, paper, Department of Science Education, U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 1 9 7 3 . . 2 8 5 Wilson, J . Tuzo, Continental D r i f t , S c i e n t i f i c American, Vol. 208, No. 4, pp.: 86-100, 1 9 6 3 -Wilson, J. Tuzo, Continents Adrift, (Preface), Freeman, San Francisco, 1972. Woodrov;, Janice, Harvey, Kenneth, & Danner, Wilbert R., Reading About Science 5 , Holt Rinehart Winston, 1 9 7 0 . Zim, H.S. & Shaffer, P.R., Rocks and Minerals, Golden Press, New York, 1 9 5 7 -286 ADDENDUM P a r t 1 P r o p o s e d C u r r i c u l u m f o r G r a d e 3 287 INTRODUCTION Can you imagine a world without water? without air? without sunshine? without even a s o l i d surface upon which to stand? Such places do e x i s t ! The planet Mercury has no l i q u i d water, the Moon has no a i r , Pluto has no sunshine, and J u p i t e r has no s o l i d surface. Our Earth Is the only planet i n our solar system which has a l l of these. In t h i s u n i t you w i l l l e a r n more about the surface of our planet, and about some of the forces which cause i t to change. 288 NARRATIVE 8 Topographic Mapping Before a geologist t r a v e l s into an area to look at the rocks, he f i r s t examines a topographic map. Topographic maps are made from photographs taken from aeroplanes. They show only the surface features of the land - mountains, r i v e r s , f o r e s t s - and man-made objects - roads, b u i l d i n g s . They do not t e l l us anything about the rocks. In the next few Investigations, you w i l l look at some of the things which may be learned from a topographic map of part of southwestern B r i t i s h Columbia. Questions 1. Why do you suppose that topographic maps are made from a e r i a l photographs rather than from notes and measurements made by people on the ground? .2. Why do you suppose that topographic maps must be revised much more frequently than geologic maps? INVESTIGATION 9 The Legend on a Map The legend. Most topographic maps cover quite a large area of the country. Although i t i s possible to show i n d i v i d u a l roads and bu i l d i n g s , there i s u s u a l l y not enough room to describe or name each i n printed words. Instead, map-makers use a set of standard symbols. The table explaining the meaning of each of these symbols i s c a l l e d the legend. In t h i s Investigation, you w i l l l e a r n to use the legend on a topographic map. 289 Purpose: to use the legend on a topographic map Procedure A. Examine the legend on the back of the map, showing the meaning of the various symbols, then answer the following questions about the Port Moody area. 1 . What do these colours represent when they cover a large area of the map: blue, green, white, red? 2. Draw and l a b e l the symbols which represent a: school, church, post o f f i c e , mine, quarry, navigation l i g h t . 3 . Draw and l a b e l the symbols which represent a: four lane freeway, t r a i l , single track railway, double track railway, power transmission l i n e , c i t y boundary. 4 - . . How many of each of the following are found within the c i t y boundaries of Port Moody? Schools, churches, sawmills, mines, o i l r e f i n e r i e s , wineries, post o f f i c e s , navigation l i g h t s ? Conclusion What d i d you lea r n about maps i n t h i s Investigation? INVESTIGATION 10 The Scale of a Map The scale. A one page map of Canada could not possibly show the p o s i t i o n of your school accurately. A map large enough to show your school could not e a s i l y show the whole of Canada. Maps are drawn to d i f f e r e n t scales, depending upon how much area has to be covered, and upon how much d e t a i l has to be shown. Purpose: to use the scale on a topographic map. 290 Fig.102 A medium scale map i s able to show more d e t a i l than the small scale map. 2 9 1 F i g . 103 A l a r g e s c a l e map covers a ve ry s m a l l a r e a , but i s a b l e to show d e t a i l s which are too t i n y t o be seen on s m a l l s c a l e maps. 2 9 2 Procedure A. Examine the scales on the lower edge of your map, then answer the following questions. 1 . Map scale i s frequently given as a r a t i o n such as 1 : 2 5 0 0 0 0 . This would mean that 1 cm on the map represents 2 5 0 0 0 0 cm on the ground. What i s the scale of your map? 2 . The scale may also be shown as an actual measurement, which may look l i k e t h i s : 1 0 0 0 0 1 0 0 0 2 0 0 0 3 0 0 0 4000 Metres On older maps, t h i s scale shows feet or miles. Newer maps show metres or kilometres. Make a neat sketch of "the scale (or scales) shown on your map. ,5. To use the scale, you need a piece of paper with at l e a s t one st r a i g h t edge. To f i n d the distance between two landmarks, place the paper so the edge touches both, and make a small mark by each. Then move the paper to the scale and estimate the distance between the two marks. On the map of the Port Moody area, f i n d the approximate distance i n metres between the following p a i r s of landmarks. a) Turtle Head to Roche Point. b) Jug Island to Lone Rock. c) The length of. the underground aqueduct (water tunnel) between Coquitlam Lake and Buntzen Lake. d) The length of Como Lake. e) The width of the narrowest part of Indian Arm. f ) The distance from t h i s school to the point where Noons Creek flows under a railway track. 293 g) The width of the i n l e t , from Reed Point to Sunnyside Beach. h) The approximate length of Mossom Creek. i ) The approximate length of Indian Arm, from the Indian River to Burrard I n l e t . j) Find the approxiamte area of Croker Island. (Multiply length by width). Conclusion What i s the scale on a map used for? INVESTIGATION 11 A l t i t u d e on a Map A l t i t u d e . Topographic maps are used to show the height of the land above sea l e v e l at various l o c a t i o n s . This height i s c a l l e d the a l t i t u d e . This i s done ei t h e r by giv i n g a point a l t i t u d e , or by t r a c i n g contour l i n e s . On older maps, these a l t i t u d e s are given i n f e e t . On newer maps they are given i n metres. Purpose: to determine the a l t i t u d e of various landmarks by using a topographic map. Procedure A. A point a l t i t u d e i s us u a l l y used f o r a mountain peak or a lake. I t i s shown as.a small number p r i n t e d beside the peak, or on the surface of the lake. Make a l i s t showing the a l t i t u d e of these landmarks: Buntzen Lake Mount Burke Burwell Lake Coquitlam Mountain Mount Bishop Widgeon Peak Mount Elsay Golden Ears 294 Mount Seymour Coquitlam Lake Seymour Lake The unnamed peak about 3 0 0 0 metres southwest of the north end of Coquitlam Lake. B. Contour l i n e s are l i n e s p r i n t e d on the map, usually l i g h t brown i n colour. They connect together a l l the locations at a p a r t i c u l a r a l t i t u d e . For instance, a l l the points 100 metres above sea.level would be connected by a contour l i n e . A l l the points 200 metres above sea l e v e l would be connected by another contour l i n e . Likewise. 300 metres, 400 metres, and so on. Where the land i s very steep, the contour l i n e s appear very close together on the map. Where the land i s almost f l a t , the contour l i n e s are quite f a r apart. Make a l i s t showing the a l t i t u d e of these landmarks: Eagle Mountain H i l l N of Burns Point Burnaby Mountain H i l l E of Bedwell Bay Ca p i t o l H i l l Gopher Lake Mount F e l i x Croker Island Cypress Lake Moody J r . Sec. School Cypress Mountain Sheridan H i l l Dennett Lake Mount Dickens Obelisk Peak Mike Lake Coquitlam Island Widgeon Lake Questions 1. I f a person were able to hike along the course of a contour l i n e , would he be walking u p h i l l , downhill, or le v e l ? 2 9 5 2. Why can contour l i n e s on a map never cross each other? 5 . What contour l i n e or point a l t i t u d e would you expect to f i n d at sea level ? Conclusion What information have you learned to obtain from maps i n t h i s exercise? INVESTIGATION 12 Drawing a Land P r o f i l e from a Map P r o f i l e s . Contour l i n e s on topographic maps can also be used to help draw a sideways view, or p r o f i l e of the land surface. Purpose: to use contour l i n e s to help draw a p r o f i l e of the land surface. Procedure A. Examine Figure 104 showing how to draw a p r o f i l e . Use the same method to draw a p r o f i l e of the land surface from the south end of Raccoon Island to the dam at the south end of Coquitlam Lake. Use the 5 0 0 foot contour l i n e s when making your marks. B. On your f i n i s h e d p r o f i l e , l a b e l the loc a t i o n s of Indian Arm, Buntzen Ridge, Buntzen Lake, Eagle Mountain, and Coquitlam Lake. Conclusion In t h i s Investigation, what d i d you lear n to do with a topographic map? 296 Figure 104. How to draw a p r o f i l e from a contour map. 297 ' Fold along t h i s l i n e  4-000 4-000 3 5 0 0 3 5 0 0 3 0 0 0 3 0 0 0 2 5 0 0 2 5 0 0 2 0 0 0 2 0 0 0 1 5 0 0 1 5 0 0 1 0 0 0 1 0 0 0 5 0 0 5 0 0 0 Figure 1 0 5 . Outline sheet f o r drawing p r o f i l e . 0 298 THE WORLD OF WEATHERING AND EROSION The surface of our Earth i s constantly changing. Many powerful forces are working to wear i t down. Trees break rocks apart, r a i n washes d i r t downhill, and wind blows dust away. Fortunately, other forces are working equally hard to b u i l d up the surface, otherwise the Earth would be completely f l a t ! Volcanoes p i l e up lava, and c o l l i s i o n s between the slowly moving continents crumple the surface to make mountains. In t h i s section, we w i l l study weathering and erosion, the forces which break down the Earth's surface. NARRATIVE 1 $ Weathering Weathering i s the process by which large pieces of rock are broken down into smaller pieces of rock. The forces which weather rock are c l a s s i f i e d i n t o three groups: a) Physical weathering i s the process of wearing away rock by non - l i v i n g things. The actual chemical makeup of the rock i s not changed. The rock i s simply ground down int o smaller pieces. For example, r a i n and wind can wear rock away. b) Chemical weathering i s the process of breaking the rock down chemically. As an example of chemical weathering, rocks which contain i r o n w i l l eventually r u s t . . c) B i o l o g i c a l weathering i s the breaking down of rock by l i v i n g things. For example, tree roots can s p l i t rocks apart. (Janes, 1976) 299 Fie.106. Physical weathering near O l i v e r , B. shale i s weathering out from between layers harder sandstone. 3? F i g . 107. Chemical weathering i n the Yukon T e r r i t o r y . ThS stains on the mountainside are caused by chemical weathering of metal ore deposits. 200 301 Questions 1. L i s t three ways i n which non - l i v i n g things can weather rock. 2. L i s t three ways i n which l i v i n g things can weather rock. 3. A plant c a l l e d a l i c h e n releases small amounts of acid which weather rock. What kind of weathering does t h i s represent? INVESTIGATION 14- Rock Weathering Purpose: to study weathering of rock. Procedure A. Write the term "weathering" and i t s meaning i n your notebook. B. (Demonstration) P i l l a small glass b o t t l e with water and seal., i t with a metal screw cap. Put the b o t t l e inside a p l a s t i c bag, and place i t i n a f r e e z e r . Wait 24- hours. Describe what has happened to the bottle? Explain why t h i s happened. I f something s i m i l a r happened to a rock, would i t be an example, of p h y s i c a l , chemical or b i o l o g i c a l weathering? C. (Demonstration) Take three pieces of s t e e l wool. Place one i n a dry beaker, the second i n a beaker h a l f f i l l e d with water. Wet the t h i r d piece, then place i t i n a dry beaker. Cover a l l three beakers. Wait 24- hours. Describe what has happened to each piece of s t e e l wool. Explain why each r e s u l t occurred. I f something s i m i l a r happened to a rock, which type of weathering would i t represent? D. (Demonstration) Place a small piece of limestone i n a weak sol u t i o n of hydrochloric a c i d . Wait 24- hours. 302 Describe what has happened to the limestone. Explain why t h i s occurred. I f something s i m i l a r happened to a rock, which type of weathering would i t represent? E. (Demonstration) Make a mixture of p l a s t e r of p a r i s and soaked corn or bean seeds. Allow i t to harden. Wait several days. Describe what happens to the a r t i f i c i a l rock. Explain why t h i s occurs. Which type of weathering does t h i s represent? Questions 1 . Give two examples of b i o l o g i c a l weathering not already mentioned i n t h i s report. 2. Give two examples of p h y s i c a l weathering not already mentioned i n t h i s report. 3- Rainwater d i s s o l v e s a small amount of carbon dioxide from the a i r to form a weak s o l u t i o n of carbonic a c i d . What w i l l t h i s do to limestone? 4 . O i l r e f i n e r i e s s i m i l a r to those i n Port Moody frequently release gases containing sulphur i n t o the a i r . These gases dissolve i n rainwater to form acids. What might t h i s do to buildings with stone facings? 5. In southern B r i t i s h Columbia, warm days often alternate with cold nights, e s p e c i a l l y i n spring and autumn. Explain how, i n a wet climate, t h i s combination of conditions can cause rock to weather r a p i d l y . , Conclusion What have you learned about weathering i n t h i s investigation? 3 0 3 INVESTIGATION 15 Water on the Earth Water. You drink i t , you eat i t , you wash with i t . I f you have a mass of 50 kilograms, your body contains between 50 and 55 kilograms of water (Otto et a l , 1 9 7 7 ) - You could not l i v e without water. Without water there would be no oceans, lakes or r i v e r s , no clouds i n the sky, no r a i n or snow, no g l a c i e r s or icebergs. No l i v i n g things (as we know them) could e x i s t on Earth. Our planet would be one gigantic desert, hot, rocky and dry. In t h i s i n v e s t i g a t i o n , you w i l l study how water moves from one part of the Earth to another. Purpose: to examine how water moves from one place to another on.the Earth. Procedure A. Make a sketch of the apparatus which represents the Earth. Label each part of your sketch. B. What do these parts of the model represent on the r e a l Earth: a) l i g h t bulb b) i c e tray c) water i n the bottom of the tank d) rocks? C. What do you observe forming on the glass beneath the ice tray? How does the water return to the bottom of the tank? What natural process does t h i s represent? D. What do you observe forming on the sides of the tank? How does water t r a v e l upwards from the bottom of the tank? On Earth, what causes water to t r a v e l upwards from the ocean into the atmosphere? How does water t r a v e l from the clouds back to the earth? In what form does water t r a v e l from.the clouds back to the earth i f the temperature i s 304-l e s s than 0 UC? E. Water is.found i n many d i f f e r e n t places on Earth. These places are c a l l e d r e s e r v o i r s . A few r e s e r v o i r s are named below. lakes atmosphere g l a c i e r s & i c e sheets streams & r i v e r s s o i l moisture oceans biosphere ( l i v i n g things) ground water Figure 109A Water r e s e r v o i r s F. Using a f u l l page, copy the diagram from Figure 1 0 9 into your notes. Draw an arrow from "oceans" to "atmosphere" and l a b e l i t "evaporation". This i s the process by which water t r a v e l s from the oceans to the atmosphere. Next draw an arrow from "atmosphere" to "lakes". Label t h i s arrow with the name of the process which moves water from the atmosphere to a lake. G. Draw more arrows on your diagram, l a b e l l i n g each one as you go. When you are f i n i s h e d , you must have at l e a s t one 3 0 5 arrow entering each box, and at lea s t one arrow leaving each box. Questions 1 . Estimate how much water you use each day. Hints: 1 t o i l e t f l u s h = 50 l i t r e s 1 dishwash (by hand) = 18 L 1 bath = 110 L 1 short shower = 75 L 1 "glass" of water = 0.25 L 1 tooth-brushing with water l e f t running = 1 . 5 L 1 washing machine load of laundry (estimate your share of the load) = 1 7 5 L 2 . Multiply your answer to Question 1 by 3 6 5 - How much water do you use i n a year? 3 . M u l t i p l y your r e s u l t f o r Question 2 by 2 2 0 0 0 0 0 0 , (the approximate number of people i n Canada). How much water do Canadians use i n one year? Note that your r e s u l t only accounts f o r personal use of water. Industry uses much more. For example, i t takes 1 2 0 0 0 0 l i t r e s of water to produce 1 tonne of s t e e l . Conclusion What d i d you le a r n about movement of water i n t h i s Investigation? 306 NARRATIVE 16 The Hydrologic Cycle In Investigation 15, you learned how water i s constantly moving from one r e s e r v o i r to another. This movement of water i s c a l l e d the hydrologic c y c l e . During a year, huge amounts of water move through various parts of the c y c l e . These amounts are estimated i n cubic kilometres (km^). A cubic kilometre of water i s l i k e a. huge tank, one kilometre long, one kilometre wide, and one kilometre high. I t contains 1 000 000 000 cubic metres of water. This i s equivalent to 1 000 000 000 000 l i t r e s of water. Each year, about 361 000 kur of water evaporate from the ocean. At the same time, about 62 000 knr evaporate from the land. Most of t h i s water f a l l s back into the ocean as r a i n , but 99 000 km^ f a l l s back on the land. Notice that the amount of water f a l l i n g on the land i s greater than the amount of water evaporating from the land. The extra 37 000 km^ annually flows and seeps from the land back into the ocean. Much of the water evaporated from the land i s f i r s t used by plants and animals. A f i e l d of wheat may use an amount of water equivalent to a l a y e r 4-5 to 60 centimetres deep over the f i e l d . Trees use even more water than wheat. Along the B r i t i s h Columbia coast, well known f o r being wet, a f o r e s t of Douglas f i r may annually pump int o the atmosphere the equivalent of a layer of water 1.2 metres deep over i t s area. G l a c i e r s store large amounts of water on land. I f the 307 present g l a c i e r s were to melt, sea l e v e l would r i s e about 60 metres! Do you l i v e more than 60 metres above sea level? Most of the heavily populated c i t i e s of the.Earth would be drowned! The huge amount of water f a l l i n g on the land can do an impressive amount of work. The amount of power available has been estimated as nine b i l l i o n kilowatts. I f a l l t h i s power were used to erode the land, i t would be equivalent 2 to having one horse-drawn scraper at work on each 4000 m of land, day and night, a l l year long. Imagine the amount of work that could be done! Of course, a l o t of t h i s energy i s wasted. A l l the same, water does i n f a c t carry worn down rock to the sea almost as f a s t as i f horse-drawn scrapers were at work on small p l o t s of land a l l over the Earth. (Bloom, 1 9 6 9 ) . INVESTIGATION 17 Simulating Stream Abrasion So f a r , you have learned how water moves about the surface of the Earth, and how i t can be involved i n weathering rock. In t h i s i n v e s t i g a t i o n , you w i l l examine more c l o s e l y the e f f e c t that running water has on the pebbles found on the bottom of a stream. Purpose: to simulate stream abrasion of rock, and to examine i t s e f f e c t upon limestone. Procedure A. Copy t h i s data table into your report: 508 Number of Shakes Mass of Rock (grams) 0 100 200 500 • • 1000 B. Choose between 1 0 0 and 2 0 0 grams of rock. Set aside one  piece f o r l a t e r comparison. C. Use the balance to weigh the rocks. Record the r e s u l t i n your data t a b l e . D. Place the rocks i n the container, h a l f f i l l i t with water and put the l i d on t i g h t l y . E. Shake the container 1 0 0 times. Remove the rock, rinse each piece and b l o t off the excess water witb a paper towel. Reweigh the rock and record the r e s u l t i n your data ta b l e . F. Repeat Procedures D and E four more times, (a t o t a l of 5 0 0 shakes), making sure to record your data a f t e r each shaking. , . G. Put the pieces aside to soak f o r 24 hours, then repeat Procedures D, E, and F an a d d i t i o n a l f i v e times, (an a d d i t i o n a l 5 0 0 shakes). H. Draw a graph of your r e s u l t s mass of rock number of shakes 3 0 9 Questions 1 . Why do you suppose the pieces of rock were l e f t soaking i n water f o r 24- hours before you started the experiment? 2 . Choose three pieces which have been shaken 1 0 0 0 times, and compare them with the piece set aside i n Procedure B . Describe the di f f e r e n c e s , and sketch a l l four pieces. 3 « Estimate the number of shakes required to wear the rock away completely. 4-. L i s t the causes of the rock wearing away. 5. L i s t the changes i n the rocks caused by the abrasion. 6. During which season of the year i s stream abrasion most l i k e l y to occur? Give a reason f o r your answer. Conclusion What causes rocks to be worn down by a stream? 5 1 0 N A R R A T I V E 2 0 Sediment Weathering breaks rocks into smaller pieces, and these pieces may be washed away by running water. The pieces of broken and ground up rock are c a l l e d sediment. Sediment may be i n the form of large boulders, or i t may be ground up f i n e r than f l o u r . Rivers may carry sediment i n three d i f f e r e n t ways: ' 1) Bed load. This consists of rocks, pebbles and sand which are pushed and r o l l e d along the bed of the stream. These pieces of sediment are too large and heavy to be picked up and c a r r i e d by the water. 2 ) Suspended load. This material i s c a r r i e d by the water, above the bed of the stream. The pieces of suspended load are usually much smaller than the pieces of sediment i n the bed load. 3) Dissolved load. Sediment which i s a c t u a l l y dissolved i n the water. I t i s i n v i s i b l e . The amount of sediment c a r r i e d by a large r i v e r can be enormous. The Eraser River c a r r i e s an average of about 55 0 0 0 tonnes of sediment each day, or about 2 0 m i l l i o n tonnes each year. The sediment load of the Fraser i s however, dwarfed by the laod of the M i s s i s s i p p i River. Each year, the M i s s i s s i p p i c a r r i e s about 7 5 0 m i l l i o n tonnes of sediment to the sea! (Janes, 1 9 7 6 ) Questions 1 . Where does the sediment c a r r i e d by a r i v e r eventually end up? 311 2. L i s t three things which could a f f e c t the amount of sediment c a r r i e d by a r i v e r . INVESTIGATION 21 Measuring Sediment When studying a r i v e r , s c i e n t i s t s frequently measure the amount of sediment that i t c a r r i e s . In t h i s i n v e s t i g a t i o n , you w i l l study the method that they use. Purpose: to measure the amount of suspended and dissolved sediment c a r r i e d by a r i v e r . Procedure A. Set up the f i l t e r i n g apparatus as shown i n Figure 1 1 0 . B. Copy t h i s data table i n t o your report. Determination of suspended sediment Mass of f i l t e r paper + sediment g Mass of f i l t e r paper g Mass of suspended sediment g Determination of dissolved sediment Mass of evaporating d i s h + sediment g Mass of evaporating d i s h . _ g Mass of dissolved sediment __ g C. Measure the mass of the f i l t e r paper and record i t i n your data table. Use a p e n c i l to write your i n i t i a l s on the f i l t e r paper. Measure the mass of the evaporating dish, and record t h i s also i n your data t a b l e . D. Fold the f i l t e r paper and place i t i n the funnel. $12 g u r e 1 1 0 . F i l t e r i n g apparatus f o r I n v e s t i g a t i 3 1 3 F i g . m . A braided stream i n the Yukon T e r r i t o r y . (Photograph courtesy of D. K e l l y ) . 314-Moisten the paper with a few drops of water to hold i t i n place. E. Remove a beaker of water from the. bucket of r i v e r water. Before the sediment s e t t l e s to the bottom of the beaker, measure out 2 0 mL of water into the graduated c y l i n d e r . Pour the 2 0 mL into the f i l t e r paper. I f any sediment i s l e f t i n the graduated c y l i n d e r , wash i t in t o the f i l t e r with a l i t t l e clean water. _F. When a l l the water has drained from the f i l t e r , l i f t the paper c a r e f u l l y from the funnel ( i t tears e a s i l y ) and put i t i n the place indicated by your teacher so that i t may dry overnight. G. Set up a r i n g stand, asbestos gauze and bunsen burner. Heat the evaporating d i s h to evaporate the water. I f any material spatters out of the dish, reduce the heat quickly by moving the bunsen burner away. H. When a l l the water has evaporated and the dish has cooled, weigh i t and the dry sediment. Record the r e s u l t i n your data ta b l e . Subtract to f i n d the amount of dissolved sediment i n your water sample. I. When your f i l t e r paper i s dry, weigh i t and record the r e s u l t i n your data t a b l e . Subtract to f i n d the amount of suspended sediment- i n your water sample. Questions 1. What was the t o t a l amount of sediment i n your sample? 2 . The average flow of the Fraser River i s 2 6 3 0 0 0 0 l i t r e s per second. I f the average sediment load i s 6 5 7 5 0 0 grams per second, c a l c u l a t e the average number of grams of 3 1 5 sediment i n each l i t r e of Fraser River water. (Remember that even t h i s small quantity of sediment i n each l i t r e s t i l l moves 20 0 0 0 0 0 0 tonnes each year!) 5 . Why could you not see the dissolved sediment before you evaporated the sample? 4. Figure111 shows an example of a braided stream. I t s load of sediment i s so large that the stream channels are frequently blocked, causing the stream to change course. a) Is the sediment c a r r i e d by a braided stream mostly bed load, dissolved load, or suspended load? b) During which season of the year w i l l t h i s stream move the greatest amount of sediment? Give a reason f o r your answer. Conclusion In t h i s i n v e s t i g a t i o n , what d i d you le a r n about f i n d i n g the amount of sediment i n a sample of water? INVESTIGATION 22 V a l l e y Formation About one-third of the water which f a l l s on land . flows back to the sea i n r i v e r s and streams, or seeps through as ground water. The remainder evaporates. Rivers are major changers of the Earth's surface. Some carve narrow canyons and deep gorges. Others form wide f e r t i l e v a l l e y s and d e l t a s . In southwestern B r i t i s h Columbia, the Fraser River has produced superb examples of a l l of these landforms. North of the v i l l a g e of Hope where the r i v e r emerges from the mountains, i s the Fraser Canyon, one of the best 316 5 1 7 Wyoming, U.S.A. 318 320 known scenic regions of Canada. From Hope to the sea, the r i v e r flows f o r nearly 200 kilometres through the wide, f l a t , Fraser Valley, one of the most productive farming areas i n B r i t i s h Columbia. F i n a l l y , where the r i v e r discharges into the sea i s the Fraser Delta, a feeding ground f o r hundreds of species of f i s h and b i r d s . Purpose: to study the formation of v a l l e y s Procedure A . Examine Figures'! 12, 113and114-. How f a s t do the r i v e r s appear to be flowing? What l e t t e r of the alphabet does the shape of the v a l l e y i n Figure 113 resemble? B. Set up a stream table with a slope of about 20°. With your f i n g e r , make a shallow groove i n the sand to d i r e c t the water flow i n a s t r a i g h t l i n e . S t a r t the water flowing and wait f o r a few minutes. Does the water cut a wide f l a t v a l l e y or a deep narrow va l l e y ? Figure 115 shows a canyon which once contained a r i v e r . Did t h i s r i v e r probably flow r a p i d l y or slowly? C. Examine Figures 116,117 and 118 Do these r i v e r s appear to be flowing r a p i d l y or slowly? Is the Fraser Valley i n Figure 116 wide and f l a t or steep and narrow? D. Figures 117,118 and 119 show meandering r i v e r s . These are r i v e r s whose paths wind i n wide sweeping curves back and f o r t h across t h e i r v a l l e y s . Look at the shape of t h e i r v a l l e y s and state whether the r i v e r s flow r a p i d l y or slowly. E. Set up a stream table with a slope of about 10°. With your f i n g e r , make a shallow groove In the shape of a meandering r i v e r . Start the water flowing and wait f o r 3 2 1 a few minutes. Does the water continue to make a wide f l a t v a l l e y , or does i t s t a r t to make a canyon? What kind of v a l l e y s do slow r i v e r s produce? F. Figure 119 i s an a e r i a l photograph of a section of the bank of a meandering r i v e r . The r i v e r has washed s o i l away from the lower part of the bank, causing the l a n d s l i d e . I f t h i s process continues, the course of the r i v e r w i l l eventually change. Sometimes t h i s happens i n such a way that a section of r i v e r channel i s cut o f f , forming a lake such as those i n Figures 117 and 118. This type of lake i s c a l l e d an oxbow lake. Draw a se r i e s of four diagrams i n your notes, showing how changes i n the course of a meandering r i v e r can form an oxbow lake. Questions 1 . Water by i t s e l f does not wear away rock very e a s i l y . E xplain then, how a r i v e r i s able to erode a deep canyon. (R e c a l l Investigation 1 7 ) . 2 . Which would a f a s t r i v e r i n a deep rock canyon tend to erode more, the bottom or sides of i t s va l l e y ? 3. Which would a slow r i v e r i n a wide, f l a t v a l l e y of soft s o i l tend to erode more, the bottom or sides of the r i v e r bed? Conclusion Summarize t h i s i n v e s t i g a t i o n by de s c r i b i n g i n a few short sentences how the shape of a v a l l e y depends upon the speed of a r i v e r , and by the hardness of the s o i l or rock along the sides of the v a l l e y . 322 323 F i g . 1 1 8 . Meanders and an oxbow l a k e on t h e P a r s n i p R i v e r i n n o r t h e r n B.C. Fig.119. L a n d s l i d e on t h e T a k i n i R i v e r i n t h e Yukon T e r r i t o r y . A second l a n d s l i d e i s about t o o c c u r b e s i d e t h e f i r s t . As t h i s p r o c e s s c o n t i n u e s , t h e r i v e r g r a d u a l l y changes c o u r s e . ( P h o t o g r a p h c o u r t e s y o f D. K e l l y ) . 324 INVESTIGATION 25 Sand Much of the sediment c a r r i e d by a large r i v e r l i k e the Fraser i s i n the form of sand. By examining sand, we can learn much about the o r i g i n a l rock from which the sediment was formed, even though i t may be many kilometres away. Purpose: to examine a s e l e c t i o n of sands Procedure A. Copy t h i s data table into your notebook: Sample Location O v e r a l l Colour Colours of Separate Grains Shapes of Grains (Round or Jagged) Unusual Features O r i g i n a l Rock B. Spread a small amount of each sample i n a p e t r i dish, and examine i t with a magnifying glass or stereo-microscope. Record your observations i n the f i r s t four columns of your data ta b l e . C. Record your observations from these "unusual features" t e s t s i n the f i f t h column of your t a b l e . a) Magnetism: te s t each sample with a magnet. b) L i f e : look f o r evidence of animal l i f e i n each sample. c) Acid t e s t : put one drop of d i l u t e hydrochloric acid on each sample. D. Examine a geologic map of Coquitlam. What kinds of rock 325 form the mountains surrounding Widgeon Lake? Does your sand sample from Widgeon Creek resemble these rocks i n any way? Describe the resemblance. Record the names of these rocks i n the l a s t column of your data table, opposite the sample from.Widgeon Creek. E. What kind of rock i s black, with very small c r y s t a l s ? Record your answer opposite the black Hawaiian sand. F. Examine the sample of o l i v i n e rock. Describe i t s appearance. Record the name " o l i v i n e " opposite the sand which most c l o s e l y resembles t h i s rock. G. The remaining Hawaiian sand i s made from the skeletons of once l i v i n g sea animals and plants which inhabit the co r a l reefs surrounding the i s l a n d s . Although i t i s not r e a l l y a rock, record the o r i g i n a t i n g rock of t h i s sample as " c o r a l reef". Questions 1. Why i s i t reasonable to assume that the makeup of a sand near the mouth of a r i v e r i s s i m i l a r to the makeup of the rocks upstream? 2. Why are grains of soft or e a s i l y broken minerals seldom found i n sands? 3 . I f the sand which f i z z e d with acid were crushed and compressed into a sedimentary rock, which rock would i t form? I f t h i s sedimentary rock were then changed into a metamorphic rock, what would the name of that rock be? 4-. Hawaii i s famous f o r i t s volcanoes. I f you d i d not know t h i s , how could sand samples t e l l you that the Hawaiian 326 Islands were volcanic? Conclusion What can be learned by studying sand? NARRATIVE 26 Landslides Rivers deposit sediment slowly. Landslides deposit sediment very r a p i d l y . The next few pages are excerpts from an account of one of the most famous lan d s l i d e s i n Canadian h i s t o r y . In 1 9 0 3 , the town of Frank i n south-western Alberta was wiped out by THE FRANK SLIDE Suddenly, there was a horrendous sound high above them, l i k e an almighty, f i n a l clap of thunder, as seventy m i l l i o n tons of rock broke away from T u r t l e Mountain. As i t began plummeting down the p r e c i p i t o u s slope, i t sent a b l a s t of f r e e z i n g a i r r a c i n g before i t . Like a screaming juggernaut, the rock careened down the mountain side, sweeping over the mine entrance, erasing i t e n t i r e l y ; crashing against the mine t i p p l e and h u r l i n g Clark, Farrington and Tashigan f a r out into e t e r n i t y . I t caught the blacksmith shop and the s o l i t a r y railway car and f l u n g them two miles across the v a l l e y , t w i s t i n g the mine spur tracks l i k e threads of s i l k . Seconds a f t e r the ra c i n g engine and i t s stupefied crew cleared the bridge, the rocks h i t one end of the wooden superstructure. Icy water sprayed high into the a i r as the bridge swung 327 sideways and then subsided into the Old Man River. By then, however, the rocks were already f a r across the eastern f l a t s . Ahead of the deadly rock f a l l , a s o l i d wall of a i r raced across the v a l l e y , toppling the fl i m s y houses, shacks and tents, h u r l i n g men, women and c h i l d r e n hundreds of yards. Those asleep had no time to waken, and those awake never knew what was happening as behind the wind came the churning, grinding mass of rocks which made the night unbelievable with the noise and the sparks, as massive boulders leaped high into the a i r and clashed with each other. The power plant was o b l i t e r a t e d i n an instant and the seething mass hurtled out onto the v a l l e y f l o o r , splaying out l i k e a fan. V/hile the main stream of rocks shot ahead, smashing the remains of the temporary dwellings; cascading over the l i v e r y stable and the Dawes Cabin, the the construction camp and the boxcar of dynamite before expending i t s e l f over the farm of Alex Graham and the cemetery behind; another spur shot eastward, cascading over the farm of James Graham and the bunkhouse and the two storey farmhouse, burying the b u i l d i n g s with a l l occupants. a hundred feet deep. At the same time, another spur, fo l l o w i n g with almost f a n a t i c a l p r e c i s i o n the east bank of Gold Creek, pushed an i c y wall of gray mud ahead of i t and sent i t crashing against the row of miners' cottages on the o u t s k i r t s of Frank. A f i v e hundred ton boulder, drunk with i t s own power, jumped" the creek and spun to r e s t within the very v i l l a g e i t s e l f . 328 A hundred seconds a f t e r i t s f a t e f u l plunge, the biblioclasm of rocks had s l i d across the valley, and come to rest f i v e hundred feet up the opposite slope beyond the tracks. Over the scene, a s w i r l i n g mass of grey dust hung l i k e a natural shroud. I t was 4:10 a.m., A p r i l 29th, 1903-Joseph Dooeck, who was o i l i n g engines i n the t r a i n shed two hundred yards from the d i s a s t e r , f e l t the earth shake and heard the monstrous noise. He stepped outside and peered eastward, but. could see nothing i n the darkness. With a p h i l o s o p h i c a l shrug of h i s shoulders, he returned to h i s job. "Mormon B i l l " , a well known l o c a l character, was standing on the s t r e e t i n f r o n t of the Miners' Hotel, co o l i n g off a f t e r a strenuous night of poker. He was rocked on h i s feet by the b l a s t of wind, heard the unholy din, and stood l i s t e n i n g . In l e s s than two minutes, a l l was s t i l l . Although a l l around him men and women were beginning to rush i n t o the s t r e e t In t h e i r night a t t i r e , Mormon B i l l p u l l e d himself together, wrote the sensations of f to too much l i q u o r and went home to h i s shack to sleep soundly. John Anderson, a more sedate and methodical man, who had gone to bed at a respectable hour, was awakened by a t e r r i b l e b l a s t of wind that shook h i s house from shingles to s u b - c e l l a r . Bounding to the window i n n i g h t s h i r t , he was just i n time to see what he thought was a cloud :of 329 smoke cascading past h i s home, only a few scant yards from Gold Creek. Unaware that the smoke, or dust, was a c t u a l l y a sea of limestone h u r t l i n g past, Anderson waited u n t i l the noise ceased and then went back to bed, unaware that i n the morning he-would look out of the same window i n u t t e r d i s b e l i e f . A hundred miles to the north, two. young gallants who had gust taken t h e i r g i r l f r i e n d s home a f t e r a dance at Cochrane, reined i n t h e i r team. Both had heard what they thought was the sharp report of a giant r i f l e being f i r e d i n the mountains to the south. They checked t h e i r watches and saw that i t was 4:10 a.m. The Entombed Miners As Joe Chapman and h i s nineteen men walked up the spur l i n e to the mine entrance that morning of A p r i l 29th, 1903, they had no premonition of danger. I t was true that strange things had been happening i n the mine; two-foot timbers set one night had been found s p l i n t e r e d by the day crew, and upraises where the coal had been removed had mysteriously, s i l e n t l y closed overnight. But, these occurrences had taken place four or f i v e months before, and since then the b e l l y of the T u r t l e had been quiet. There had been a minor earthquake the year the mine opened, but t h i s had had no apparent i l l e f f e c t . The mine had been r e l a t i v e l y free from serious cave-ins or accidents. Two young miners had been k i l l e d i n a gas explosion the previous October, but i t was understood that they had entered the mine 3 3 0 wearing the old s t y l e open flame lamps instead of the new safety l i g h t s . Leaving Tashigan at the mine t i p p l e , where he operated the scales and coal washing equipment, the r e s t entered. The d r i f t mine entered an outcrop of nearly v e r t i c a l coal seam about t h i r t y f eet above the r i v e r l e v e l . The seam i t s e l f , which varied from 9 to 3 0 feet i n width, came from the d i r e c t i o n of goat mountain, passed under the town of Frank and went through Tur t l e Mountain i n an almost north and south d i r e c t i o n , p a r a l l e l i n g the axis of the mountain i t s e l f . From the mouth of the mine, the d r i f t rose sharply to a height of nearly twelve hundred f e e t . Already the mine had been worked back some f i v e thousand feet from the entrance. Because of the nearly v e r t i c a l nature of the main vein, mining was a simple operation. The coal was merely worked loose and allowed to f a l l down the i n c l i n e to the main manway, where i t was loaded on the mine cars and hauled by horse to the t i p p l e on the outside. At one time the mine had employed nearly 3 0 0 men i n the workings, but i n the winter of 1 9 0 2 nearly 1 0 0 of these had been weeded out. The mine was then only operating one day s h i f t , with a night crew f o r timbering and maintenance purposes. As they penetrated the mine tunnel, the. men dropped off one by one to attend to t h e i r d u t i e s . Alex Grant and his d r i v e r took one of the f i v e horses stationed at the entrance and began checking the trackage. Fred Farringtoh and Alex Clark took other horses and began hauling out cars - 3 3 1 of coal l e f t by the day s h i f t . William Warrington, the timberman, set about h i s never-ending task of checking the mine timbers, t e s t i n g them, repl a c i n g damaged ones, or s e t t i n g up new ones. As the night wore on, lamps glowed dimly i n the tunnels and upraises. Men worked alone, or i n p a i r s , occasionally passing one another i n the workings, but e s s e n t i a l l y t h e i r s was lonely work that took them alone to d i f f e r e n t parts of the workings. Towards four o'clock, Clark and Farrington took loads of coal out to the mine t i p p l e and sat down to eat t h e i r lunches with Tashigan. None of them were ever seen a l i v e again by t h e i r companions. Alex W. Grant and h i s d r i v e r f e l t a shock, l i k e a severe bump, just a f t e r four i n the morning. Thinking i t was a gas explosion, and f e a r i n g that i t might be followed by after-damp, they raced towards the mine entrance. The tunnel around them was heaving and t w i s t i n g , sending down small showers of rock and c o a l . They reached the end of the tunnel, only to f i n d a shattered mass of timbers and f a l l e n rock. As they gazed i n s t u p i f i c a t i o n , they were joined by three or four others who came running from the depths of the mine. One man panicked at the sight of the.blocked tunnel and turned to f l e e . As he d i d so, h i s foot caught i n the tracks, throwing him v i o l e n t l y to the ground and wrenching h i s l e g severely. The shock of the pain sobered him abruptly. Farther back i n the manway, Joe Chapman f e l t the 332 shudder of the earth. Then, a b l a s t of hot a i r racing down the tunnel picked him up and slammed him against the side of the passage. When .he picked himself up, he ran down the c r a z i l y heaving tracks almost a mile to the entrance. Dan McKenzie, the t a l l , lean bespectacled Nova Scotian, had been working i n an upraise some three quarters of a mile back when the sudden rush of wind, followed by a shower of f a l l i n g c o a l , flung him against the side of the mine, c u t t i n g his head. R e a l i z i n g that something unusual had happened, he ignored the wound i n h i s scalp and raced down the manway. At the blocked e x i t , trapped and breathless from t h e i r f r a n t i c dashes f o r safety, the seventeen miners rested momentarily and then considered t h e i r p o s i t i o n . One of them, who had worked the mine from i t s opening day and who knew intimately every inch of the timbering and tracks, examined the inside of t h e i r p r i s o n and concluded that they were trapped at l e a s t three hundred f e e t from the outside. The news dismayed them, even though some others, more o p t i m i s t i c , f e l t that they could not be more than f i f t y or s i x t y feet back. Leaving Warrington, whose l e g had been severely squeezed i n the heaving tunnel, the r e s t made t h e i r way to the lower l e v e l , hoping to f i n d the e x i t there s t i l l i n t a c t , but were shocked to f i n d that the lower manway was already f i l l i n g with water from the Old Man River. Even as they studied i t , they saw that the water was r a p i d l y backing up in t o the mine. The mine was deathly quiet and the f l o o r had ceased to 333 shudder as they made t h e i r way back to the entrance where Warrington and the other injured man waited. But, there was consciousness of new dangers. Cut off by the r i s i n g water, sealed i n by the blocking of the main entrance, they r e a l i z e d that i f the a i r shafts had also been pinched t h e i r supply of a i r would be quickly fouled. I t was possible, also, that the upheaval had loosened pockets of gas that would begin c o l l e c t i n g i n the upper regions of the tunnels. Maintaining t h e i r calm, they returned bravely to t h e i r o r i g i n a l work spots and got t h e i r t o o l s . Once back at the entrance they began methodically to t r y to drive t h e i r way through the shattered timbers and crumpled rocks. While they were working, Dan McKenzie and two others climbed three hundred f e e t up ladders to the Nicholson Level as the old workings of the mine were c a l l e d . While gas was already c o l l e c t i n g i n the upper l e v e l , t h e i r . i n v e s t i g a t i o n s also revealed that the a i r shafts had been completely sealed o f f by the catastrophe. They had to return In defeat to t h e i r comrades below. The men working at the entrance were making l i t t l e or no progress against the snarled mass of timber and rocks, and panic began to r i s e i n the throat of each man. At that point, one man took charge. Some say i t was Joe Chapman, the foreman; others say that i t was Dan McKenzie; while others believe that i t was C h a r l i e F a r r e l l . R e a l i z i n g that a seam of coal outcropped on the mountain some distance back, t h i s man set h i s mates to digging upward through the narrow seam of coal, b e l i e v i n g that they were s u f f i c i e n t l y 334 close to the surface at t h i s point to make such a scheme f e a s i b l e . There was no c e r t a i n t y as to how f a r they were from the surface, nor whether they might encounter some, insurmountable obstacle; only the growing appreciation that the a i r was becoming l e s s v i t a l , l e s s able to sustain t h e i r e f f o r t s . Despite t h e i r cramped quarters, the men kept doggedly at t h e i r task, working i n r e l a y s of two or three at a time. S t a r t i n g sometime between 8:30 and 9:00 i n the morning, they laboured s t e a d i l y , slowly, painstakingly; giving way grudgingly to re s t when.others took over. Towards mid-afternoon, three of the miners returned to the main entrance to examine once again the jumble. The i m p o s s i b i l i t y of escape that way became even more impressed upon them. Under the increasing s t r a i n and diminishing oxygen supply, some of the men became excited, others morose. Where i n the beginning they had sung songs to sustain t h e i r courage, now they were quiet, hoping to conserve the f a s t f a l t e r i n g supply of a i r . Towards f i v e o'clock i n the afternoon, while men slumped with exhaustion against the mine wall, or sat dejectedly with head i n hands, only McKenzie and two other men s t i l l persevered. Suddenly, unexpectedly, McKenzie*s pick drove through the hardpan and broke into the open. A beam of b r i l l i a n t sunlight blinded him and a rush of clean a i r bathed h i s face. The f r e s h a i r revived the exhausted men, renewing t h e i r hopes and g i v i n g them f r e s h strength and courage. Even though t h e i r f i r s t opening came at a spot where f a l l i n g 535 rocks, s t i l l cascading down the mountainside, prevented t h e i r escape, they set to work to drive another shaft upwards through the t h i r t y - s i x feet of coal and clay. Then, t h i r t e e n hours a f t e r the s l i d e had sealed them i n , they broke out into the daylight behind some embedded boulders which shielded them from the minor rock f a l l s . Dan McKenzie, the f i r s t man out, stared i n awe and astonishment at the scene below. The s l i d e , plunging down the north slope of the mountain, had fanned out from the base and lay l i k e a stubby-fingered giant's hand of destruction on the f l o o r of the v a l l e y . A n t l i k e figures were scrambling over the rocks, searching, searching ... From a broken mass of timbers, where a row of miners' houses had stood, white smoke curled l a z i l y up into the l a t e afternoon sky. F i f t y yards below and to the l e f t , a l i t t l e knot of men were buzzing around the spot where the mine entrance had been. McKenzie c a l l e d out and the men looked up ana saw him. There was a mad, scrambling rush across the treacherous slope; a j o i n i n g of hands i n the joyous r e l i e f from overwhelming tension; and the passage of news. The seventeen men were hustled down the mountainside and across the makeshift f e r r y . Since neither Farrington, Clark nor Tashigan were among them, the tabulators had to add t h e i r names to the growing casualty l i s t . A waiting wagon c a r r i e d Warrington up the main s t r e e t , where eager photographers were on hand to snap pi c t u r e s of the l i t t l e cavalcade, and across the f l a t to Dr. Malcolmson's h o s p i t a l . 336 W h i l e t h e o t h e r m i n e r s s o u g h t o u t f r i e n d s o r r e l a t i v e s , o n e o r t w o s t o p p e d g r a t e f u l l y a t a h o t e l b a r t o w e t t h r o a t s s t i l l d r y f r o m f e a r a n d t h i r s t . M i r a c l e s a r e s e l d o m w o r k e d b y o n e p e r s o n a l o n e , a n d t h e e s c a p e o f t h e m i n e r s e n t o m b e d i n t h e b e l l y o f t h e T u r t l e w a s n o e x c e p t i o n . I t h a d t a k e n a n i n g e n i o u s a n d d a r i n g s u g g e s t i o n t o l e a d t h e m o u t , ; b u t - i t h a d t a k e n t h e c o u r a g e a n d s t r e n g t h o f a l l s e v e n t e e n t o f o l l o w t h a t p l a n . T o t h a t i n g e n u i t y a n d c o u r a g e , t h e y a l l o w e d t h e i r l i v e s . R e p r i n t e d f r o m " T h e F r a n k S l i d e S t o r y " b y F r a n k W . A n d e r s o n . Q u e s t i o n s 1. W h a t w a s b e i n g m i n e d i n T u r t l e M o u n t a i n ? 2. W h a t t y p e o f r o c k m a d e u p T u r t l e M o u n t a i n ? 3. G e o l o g i s t s e x a m i n i n g t h e s l i d e a f t e r w a r d s f o u n d e v i d e n c e o f l a r g e c r a c k s i n t h e m o u n t a i n a b o v e t h e s l i d e a r e a . . a ) H o w c o u l d w a t e r a n d f r e e z i n g t e m p e r a t u r e s h a v e p r o d u c e d a n d e n l a r g e d c r a c k s i n t h e r o c k ? b ) H o w c o u l d m i n i n g i n t h e m o u n t a i n h a v e h e l p e d t o c a u s e t h e s l i d e ? . 4-. I f t h e d e b r i s f r o m a l a n d s l i d e w e r e e v e n t u a l l y c o m p r e s s e d a n d h a r d e n e d i n t o a n e w s e d i m e n t a r y r o c k , w h a t w o u l d b e t h e n a m e o f t h a t n e w r o c k ? 3 3 7 F i g . 1 2 0 . The F r a n k S l i d e . I n 1903, 76 p e o p l e d i e d when a huge mass o f l i m e s t o n e swept down from T u r t l e M o u n t a i n . F i g . 1 2 1 . The Hope S l i d e . F i f t y m i l l i o n t o n n e s of r o c k s l i d from t h i s n ameless m o u n t a i n i n t h e e a r l y morning o f J a n u a r y 9, 1965-338 NARRATIVE 51 How F o s s i l s Are Made In general, a . f o s s i l may be formed when part of an animal or plant i s buried i n sediment. A f t e r b u r i a l , a number of d i f f e r e n t things may happen which w i l l preserve the specimen. I t i s possible i n some cases that the animal i s not changed i n any way a f t e r b u r i a l . This i s known as "actual preservation". Many s h e l l f o s s i l s found i n the Fraser Valley 3 3 9 F i g . 1 2 3 * Ammonite s h e l l . T h i s animal, l i v e d i n a sea w h i c h c o v e r e d A l b e r t a about 7 0 m i l l i o n y e a r s ago. ( P h o t o g r a p h c o u r t e s y o f B. P o e l m a n ) . 34-0 are preserved i n t h i s manner. Sometimes, minerals from ground water gradually f i l l i n the a i r spaces i n bones. This.tends to make the bone heavier, without changing i t s o r i g i n a l shape. Many dinosaur skeletons have been preserved i n t h i s way. In some cases, the ground water dissolves away the o r i g i n a l s h e l l or skeleton, one atom at a time, and replaces i t with a ' d i f f e r e n t material. Wood i s frequently " p e t r i f i e d " i n t h i s manner when the wood i s replaced by s i l i c a . I f the o r i g i n a l s h e l l or bone i s dissolved without being replaced, the r e s u l t i n g c a v i t y forms a type of. f o s s i l c a l l e d a "mould". I f the mould i s l a t e r f i l l e d i n by another material, the f o s s i l i s c a l l e d a "cast". S h e l l s are often f o s s i l i z e d as moulds or casts. Leaves, which are quite s o f t , are f o s s i l i z e d by a method c a l l e d "carbonization". Here, the hydrogen and oxygen atoms from the o r i g i n a l material are l o s t , leaving only the black or brown carbon atoms behind. Figure 122 shows a carbonized l e a f . Tracks of animals may be f o s s i l i z e d when the soft mud i n which they are made becomes hardened into rock. Dinosaur tracks from the Peace River area of northeastern B r i t i s h Columbia are displayed outside the P r o v i n c i a l Museum i n V i c t o r i a . Certain conditions seem to favour the formation of f o s s i l s . F i r s t , the animal should have hard body parts l i k e teeth or bones. Next, i t should be buried.rapidly by f i n e , moist sediment. Afterwards, the. b u r i a l s i t e should 541 remain at a constant temperature, with no rapid freezing or thawing. There should be l o t s of minerals i n the ground water. Considering a l l t h i s , probably the best place i n B r i t i s h Columbia to form f o s s i l s at present i s the edge of the Fraser d e l t a , preferably at a time when the r i v e r i s carrying l o t s of sediment. (Casanova, 1 9 5 7 ) • Questions 1 . Is there a place near where you l i v e , where f o s s i l s might be forming at present? INVESTIGATION 52 Dinosaur Study Just about eyerybod3^ has heard about the dinosaurs, those giant r e p t i l e s that l i v e d upon the Earth during the Mesozoic Era. In previous years, you have probably studied the habits of some of these animals. In t h i s i n v e s t i g a t i o n , you w i l l look b r i e f l y at some of the wa;/s i n which s c i e n t i s t s c l a s s i f y dinosaurs and d i f f e r e n t i a t e among them. Procedure A. Usual ways of movement. Copy the data table below int o your notes. Runners Walkers Swimmers Fl y e r s Crawlers Examine the pi c t u r e s of the dinosaurs i n Figures 124- to 159, looking c a r e f u l l y at the legs. L i s t the name of each dinosaur under the heading of your table which best describes the way i n which i t probably moved. • ! •• 34-2 B. Eating habits. Examine the.pictures of Allosaurus, Tyrannosaurus, Iguanodon and Camptosaurus, Figures 124-. to'127. a) Which part of the body should you look at to decide whether each animal ate plants or other animals? b) Which of these four dinosaurs appear to be meat eaters, and which appear to be plant eaters? c) Which were probably walkers, and which were probably runners when gathering food? C. Defense. How might each of these animals e i t h e r avoid attack, or defend i t s e l f ? a) Rhamphorhynchus ( F i g . 1 2 9 ) . b) Monoclonius ( F i g . 1 3 3 ) . c) Tyrannosaurus ( F i g . 1 2 5 ) . d) Ankjrlosaurus ( F i g . 1 3 1 ) . D. Size. Dinosaurs are u s u a l l y thought of as being giants. This was not always the case, as you can see from the p i c t u r e s . In each pi c t u r e , the l i t t l e g i r l i s supposed to be one metre t a l l . a) Which i s the smallest dinosaur shown? Estimate i t s height i n metres. b) Which i s the t a l l e s t , from the ground to the top of i t s head? Estimate i t s height. c) Which i s the longest, from head to t a i l ? Estimate i t s length. d) Estimate the wing span of Pteranodon (Figure 130). 343 Figure 1 2 7 . Camptosaurus. 5 4 5 Figure 129, . Rhamphorhynchus. Figure 1 5 0 Pteranodon. 34-6 347 54-9 E. Body structure. Students often confuse Tyrannosaurus' with i t s ancestor, Allosaurus. In f a c t , Tyrannosaurus did not appear u n t i l about 50 m i l l i o n years a f t e r Allosaurus became e x t i n c t . Examine the pictures of each, (Figures 124-and 125) , and describe three major ways i n which the bodies of the two animals were d i f f e r e n t . F. Bone structure. Just as the bones of modern animals d i f f e r i n many ways, the bones of dinosaurs also d i f f e r e d . a) Which dinosaurs might have had very l i g h t , hollow bones? Give a reason f o r your answer. b) Why d i d Brachiosaurus (Figure 135* have very thick, heavy l e g bones? Conclusion What d i d you lear n about dinosaurs i n t h i s exercise? NARRATIVE 35 Dinosaur P r o v i n c i a l Park A few kilometres northeast of the c i t y of Brooks, Alberta, i s an area where many dinosaur skeletons have been discovered. This area has now been set aside as a public park, where v i s i t o r s may see how these f o s s i l s are removed from the rocks. The following a r t i c l e describes how Dinosaur P r o v i n c i a l Park might have appeared, 76 m i l l i o n years ago. 350 A Walk i n the Park . How could you l i v e i n Dinosaur P r o v i n c i a l Park as i t was, 76 m i l l i o n years ago? The p r o b a b i l i t y of surviving f o r any length of time would not be very great. I f you must go, dress i n a long-sleeved s h i r t and trousers, and wear a mosquito net around your hat, f o r b i t i n g insects w i l l be abundant. Put a kni f e , machete, cord, l i g h t raincoat, hammock and mosquito netting i n your knapsack, as well as mosquito r e p e l l e n t and matches. These conveniences w i l l help you i n the beginning - enabling you to become f a m i l i a r with your surroundings and increasing your chances of long term s u r v i v a l . So w i l l a high powered r i f l e and several hundred rounds of ammunition. I f you are fortunate, you w i l l a r r i v e on a wooded, stationary sand bar near the middle of a broad stream. I f not, make your way to the nearest clump of trees where herbivorous dinosaurs are grazing q u i e t l y and undisturbed, i n d i c a t i n g that there may be no tyrannosaurs i n the immediate area. Promptly climb a t a l l open-branched tree where you can hang your hammock at l e a s t 10 metres above the ground. The most dangerous animals f o r yOu are the tyrannosaurs, both half-grown and adult, and you must lea r n t h e i r habits as soon as po s s i b l e . These animals are ag i l e and swift, not the ponderous giants pictured In children's books, and your only r e a l i s t i c hope of escape, once seen, i s to climb high i n the branches of a tre e . They depend on t h e i r keen v i s i o n to locate t h e i r prey, and may be l e a s t active at night, p a r t i c u l a r l y during the cool pre-dawn hours. 3 5 1 It would almost c e r t a i n l y be f u t i l e . t o attempt to shoot a tyrannosaur, p a r t i c u l a r l y i n the course of an attack. Their brains are very small and are well protected by bone. I f the animal were h i t i n almost any other part of i t s body, i t would not be diverted, even i f mortally wounded. Smaller, man-sized carnivorous dinosaurs would also be extremely dangerous, but here there would be some chance f o r s e l f -defence with the use of the r i f l e or, at close quarters,- a bark s h i e l d and machete. Their claws are t h e i r most formidable weapons of attack. When you have examined your immediate surroundings and are thoroughly s a t i s f i e d that there are no carnivorous dinosaurs nearby, you may descend and explore the area f o r food. Do not touch plants that have waxen compound leaves l i k e those of poison ivy, f o r members of t h i s plant family w i l l c e r t a i n l y be present. You may f i n d b r e a d f r u i t or edible nuts. A more r e l i a b l e source of food, however, w i l l be t u r t l e s and t u r t l e eggs. You may be able to spear sturgeons, but watch f o r the c r o c o d i l i a n s which, though not exceptionally large, may be bold. The d i f f e r e n t kinds of dinosaurs that l i v e i n the region of the Park should be watched c a r e f u l l y . Observe t h e i r habits and i n what way they might be dangerous; to you. I f you can k i l l an o s t r i c h dinosaur outright, by shooting i t i n the head or heart so that i t s body can be recovered without undue r i s k , .you.might f i n d t h e i r b r o i l e d f l e s h to be e x c e l l e n t . Although wild mushrooms w i l l be p l e n t i f u l i n the woods, i t would be best not to eat your 5 5 2 ostrich-dinosaur steak with mushroom gravy. These fungi must be i d e n t i f i e d p r e c i s e l y i n order to separate edible and poisonous kinds, and i t i s not -certain that many modern v a r i e t i e s w i l l be present. The small, r e l a t i v e l y i n t e l l i g e n t Sterionychosauxus' might possibly be domesticated i f r a i s e d from a hatchling. Of a l l the creatures present i t i s the only one that could, to any degree, f i l l the ro l e of a dog. Ultimately, you w i l l have to decide whether or not your chances of avoiding tyrannosaurs f o r long are very great. You would probably be safest i n the high, cool mountains to the west, but i f you f i n d your s i t u a t i o n i n the Park precarious, the p r o b a b i l i t y that you could survive a 5 0 0 kilometre trek across open t e r r a i n would be small indeed. I t would be therefore be better to construct a r a f t of small trees and f l o a t 1 0 0 kilometres downstream to the cypress swamps near the coast. There you could l i v e within the double protec t i o n of the water and the trees, r e l y i n g on f i s h f o r food. Reprinted from "A Vanished World, The Dinosaurs of Western Canada" by D. A. Ru s s e l l , National Museums of Canada. Questions 1. L i s t three things which would make l i f e uncomfortable or dangerous i n Dinosaur P r o v i n c i a l Park, 76 m i l l i o n years ago. 3 5 3 INVESTIGATION 54 Dinosaur E x t i n c t i o n Most people know that at the end of the Mesozoic Era, the l a s t of the dinosaurs died off within a very short period of time. What i s not generally known i s that at the same time, about 2 / 3 of a l l the species on earth also became extinct! The reasons f o r t h i s great e x t i n c t i o n are s t i l l unknown. Purpose: to invent a theory to account f o r the e x t i n c t i o n of the dinosaurs. Procedure Try to think of two d i f f e r e n t possible causes f o r t h i s massive e x t i n c t i o n , and write a short paragraph explaining each. Remember that you .must k i l l o f f not only the dinosaurs, but also 2 / 3 of a l l the species of animals, birds and insect s on every continent, as well as 2 / 3 of a l l the species of animals, f i s h and s h e l l f i s h i n every ocean, lake and r i v e r . 354 COQUITLAM .RIVER FIELD TRIP During t h i s course you have studied a great many to p i c s , i n c l u d i n g rocks, maps, weathering, erosion, sedimentation, deltas, f l o o d p l a i n s , l a n d s l i d e s , f o s s i l s and g l a c i a t i o n . On t h i s f i e l d t r i p you w i l l apply your knowledge of these topics to a study of the Coquitlam River, a t y p i c a l B r i t i s h Columbia coastal stream. Although the character of the r i v e r has been changed by man, i t s t i l l represents many of the landforms discussed i n t h i s course. Part A (In the laboratory) On your map of the Coquitlam River (Figure 140), l a b e l the following features: Coquitlam Lake Canadian P a c i f i c Railway Watershed gate (Stop #1) Lions Park (Stop #4) Stops #2 and #3 Port Coquitlam P i p e l i n e Road P i t t River Road Bridge Gravel P i t s Colony Park Farm (Stop #5) Lougheed Highway Fraser River Part B (In the f i e l d ) Stop #1 -On the west side of P i p e l i n e Road, ju s t south of the watershed gate i s an old l a n d s l i d e . Vegetation now covers i t , but the scar i s s t i l l v i s i b l e . The s l a n t i n g trees i n d i c a t e that the slope i s s t i l l unstable. Write a short paragraph g i v i n g two possible causes of a l a n d s l i d e i n t h i s area. Stop #2 a) Describe the shape of the v a l l e y at t h i s point. (Is i t wide and f l a t with l o t s of good farmland, or quite narrow LEAF 355 OMITTED IN PAGE NUMBERING. 356 with f a i r l y steep sides?). b) Walk to the r i v e r and look upstream and downstream. Does the r i v e r flow quite r a p i d l y or very slowly near here? c) Is the current f a s t e s t i n the middle or at the sides? d) Look at the water. Does i t appear to be carrying much sediment? Take a water sample. Later, back i n the lab, you w i l l analyse the water f o r sediment content. e) Describe the size and shape of the rocks i n the r i v e r bed. How d i d they become shaped that way? Look c l o s e l y at the rocks. Are they mostly sedimentary, volcanic, plutonic or metamorphic? Name the most common v a r i e t i e s of rock. f ) Take a sample of sand from the edge of the r i v e r . Later, back i n the lab, you w i l l study i t with a magnifier. Stop #5 Walk back to the road. Look at the. c l i f f on the west side of the v a l l e y . a) What types of material appear to make up t h i s c l i f f ? b) What types of rock would be formed i f t h i s material were compressed? c) Describe the shape of the large rocks i n the c l i f f . Was t h i s material deposited by water or ice? Explain how you a r r i v e d at your answer. d) Make a sketch of the c l i f f , l a b e l l i n g the type of material i n each of the main l a y e r s . Which layers were deposited by f a s t running water, and which by slow water? Explain how you a r r i v e d at your answer. What could have produced enough water to deposit t h i s material so f a r 357 above the bottom of the va l l e y ? e) At one time, the entire v a l l e y was f i l l e d with the same type of material observed i n the c l i f f . What has removed the material from the centre of the valley? Drive to Stop #4-During the d r i v e , answer these.questions: a) How does the shape of the v a l l e y change as we t r a v e l downstream? b) What major industry i s located i n t h i s valley? Why i s i t located here? What i s the product used for? Stop #4- (Lions Park) a) Look at the bed of the r i v e r . Describe the si z e and shape of the rocks therein. How do the sizes d i f f e r from those observed at Stop #2? What rock types are found here? Name the most common rocks. b) How much of the entire bed between the steep banks does the r i v e r presently occupy? The amount of water i n the r i v e r i s now c o n t r o l l e d by a dam at the o u t l e t of Coquitlam Lake. Before t h i s dam was b u i l t , i n which months of the year would you expect the r i v e r to carry the most and the l e a s t amount of water. Explain how you reached your answer. c) Look at the water i n the r i v e r . Does i t appear to be c a r r y i n g much sediment? Does i t appear to be carry i n g more or l e s s sediment than at Stop #2? Explain what might have caused any d i f f e r e n c e . Take a water sample f o r l a t e r sediment a n a l y s i s . Drive to Stop #5 During the d r i v e , answer these questions: 358 a) How does the shape of the v a l l e y change? What i s the general shape of the land surface now? b) One of the main i n d u s t r i e s i n part of the v a l l e y i s farming. Why i s t h i s a good area f o r farms? . Stop #5 (Colony Farm) Walk along the path towards the point where the Coquitlam River flows into the Fraser River. a) What i s the name f o r the type of land surface on each side of the r i v e r ? b) Give two ways i n which the r i v e r i s now prevented from fl o o d i n g the surrounding land. Now that floods are prevented, what must man do to maintain the f e r t i l i t y of the land? c) The r i v e r here flows i n wide, sweeping curves. What i s the name f o r t h i s type of r i v e r ? Does the r i v e r flow r a p i d l y or slowly here? d) Does the r i v e r appear to be c a r r y i n g much sediment here? Compare the amount.of sediment to that observed at Stops #2 and #4-. Would you expect t h i s s t r e t c h of r i v e r to carry mostly coarse or f i n e sediment? Explain how you a r r i v e d at your answer. e) Is there a d e l t a forming where the Coquitlam River flows into the Fraser? I f your answer i s "yes", Explain why such a d e l t a i s forming. I f you answer "no", explain why a d e l t a i s not being formed at t h i s l o c a t i o n . 359 Part C (Back i n the laboratory) a) Analyse each water sample f o r suspended and dissolved sediment. Use the method of Investigation 2 1 , with the following changes: i ) Use 1 0 0 mL of water instead of 2 0 mL. i i ) Use a 2 5 0 mL beaker to catch the water from the f i l t e r . Measure 2 0 mL of t h i s water into the evaporating dish. b) As i n Investigation 2 5 , study the sand sample under a magnifier. Write a b r i e f d e s c r i p t i o n of your observations. State the name of the type of rock from which the sand was probably formed. c ) On your map of the Coquitlam River, p r i n t a very  b r i e f (one short sentence) d e s c r i p t i o n of the r i v e r and i t s v a l l e y beside the locations of each of Stops # 2 , # 4 - , and # 5 . d) Rewrite your f i e l d notes into a neat, concise explanation of what i s to be found at each stop on the f i e l d t r i p . Remember that you w i l l be expected to turn i n both your f i e l d notes and your f i n a l written report. e) Study your observations, then write a short h i s t o r y of the v a l l e y from a time j u s t before the s t a r t of the l a s t i c e age, up to the present day. (Rorstad, 1 9 7 7 ) 360 Figure141. Northern section of f i e l d t r i p area. (B.C. Government A i r Photo) 3 6 1 Figure 14-2. Southern section of f i e l d t r i p area. (B.C. Government A i r Photo) 362 Part 2 Proposed Curriculum f o r Grade 10 363 INTRODUCTION Man has always had legends about the Earth. The ancient Hindus believed that i t was brought up from the bottom of the sea by a god shaped l i k e a boar. The Greeks thought that i t rested upon the back of A t l a s , a legendary strong-man. The Romans believed that volcanoes were the r e s u l t of Vulcan, a blacksmith, working at h i s forge. In 1650 A.D., Archbishop Ussher c a l c u l a t e d from h i s study of the s c r i p t u r e s that the Earth was created at 9:00 a.m. on Sunday, October 23, i n 4004- B.C. We may laugh at some of these theories now, but at the time, they were based upon the best Information that the people had. Our l a t e s t theories are based upon information gathered by astronomers. (Jastrow, 196?) About twenty b i l l i o n years ago, a huge cloud of dust and gas somewhere on the outer edge of our galaxy started to contract under the force of g r a v i t y . As i t became smaller and smaller, the c o l l i d i n g atoms broke apart and reformed, r e l e a s i n g a f l o o d of l i g h t and heat i n t o the surrounding space. Thus, the s t a r we c a l l our Sun was born. At the same time, smaller bodies o r b i t i n g around the,sun also formed, c o l l i d i n g with each other and growing l a r g e r . These r e s u l t e d i n the planets we know today. The process s t i l l continues as meteorites c o l l i d e with our Earth. (Press, Siever, 1978) This theory i s the best we have, based on current observations. Just as other theories changed i n the past, t h i s theory w i l l probably change i n the future as new information about the universe i s discovered. 564 Throughout h i s t o r y , man has been curious about the Earth, and attempted to f i n d out as much as he could about i t . How large i s i t ? What i s i t s shape? How old i s the Earth? What causes volcanoes and earthquakes? Why are f i s h f o s s i l s sometimes found on mountain tops, f a r from the sea? Why has erosion not worn down a l l of the mountains? How does the Earth d i f f e r from other planets? To some of these questions we now have answers. Others s t i l l require more i n v e s t i g a t i o n . INVESTIGATION 2 The Lithosphere ' During the past 10 000 years, man has made many changes to the Earth. Above the surface, he has b u i l t great towers whose tops reach i n t o the clouds. Beneath the surface, he has dug mines so deep that people are barely able to work 365 i n them. In t h i s exercise you w i l l compare the sizes of some of these man-made structures with the si z e s of some of natures structures. Purpose: to compare the sizes of some of man's structures with the size of the lithosphere. Procedure A. Draw axes on a piece of graph paper. Choose a suitable scale to cover the range from 0 to 50 km, and number the v e r t i c a l axis (Figure -143). B. Plot the following information as a bar graph. Label each bar. Feature Distance (km) Thickness of Earth's crust below continents 11 to 50 Thickness of Earth's crust below oceans 5 to 16 Highest point above sea l e v e l (Mt. Everest) 8.8 Highest point above sea l e v e l i n Canada (Mt. Logan) 6.0 Highest point above sea l e v e l e n t i r e l y i n B r i t i s h Columbia (Mt. Waddington) 4.0 Average height of continents above sea l e v e l 0.8 Average depth of ocean 3-8 Deepest part of ocean (Marianas Trench) 11.0 Deepest gas well (Oklahoma, U.S.A) 9.6 Empire State B u i l d i n g (New York, U.S.A.) 0.4 C.N. Tower (Toronto, Ontario) 0.56 (Schmid, 1 9 7 0 ) C. Draw axes on a second piece of graph paper. Choose a sui t a b l e scale to cover the range 0 to 6500 km, and number the v e r t i c a l a x i s . P l o t the following information as a bar 366 5 0 f a 40 Xi : ft 30 P o -p xi hO •H <D 20 10 0 +3 w <t> (D > W -P o Figure143. Start the graph f o r Procedure A of Investigation 2 l i k e t h i s . Pigure144. Why i s the Earth's crust t h i c k e r under a continent than under an ocean? . 3 6 7 graph, and l a b e l each bar. Feature Distance (km) Average depth to the centre of the Earth 6360 Depth to the inner core 5170 Depth to the outer core 2920 Depth to the asthenosphere (maximum depth of crust) 160 Deepest gas well 9.6 Mount Everest 8.8 C.N. Tower 0.56 Questions 1. What f r a c t i o n of the Earth's radius (6360 km) i s the maximum thickness of the crust (approximately 159 km)? Reduce your answer to lowest terms. 2. Are man-made features large or small compared to the size, of the Earth? 3. Examine Figure 144 and t r y to give one reason why the Earth's crust i s t h i c k e r under the continents than under the oceans. 4. I f you were going to d r i l l a hole through the crust, would you d r i l l i n the ocean bottom or on a continent? E x p l a i n the reason f o r your choice. 5. a) As depth under the surface of the Earth increases, would you expect the pressure of the rock to increase or decrease? b) Give one possible reason f o r the inner core being s o l i d rather than l i q u i d . Conclusion What have you learned about the si z e of the Earth? 368 NARRATIVE 5 The Atmosphere Earth s c i e n t i s t s consider the atmosphere to be the outermost layer of our planet. I t i s a layer of gas over 2500 kilometres deep. Close to the surface of the Earth where we l i v e , i t i s made up of two main gases, nitrogen (N2) and oxygen ('C^). At higher a l t i t u d e s i t i s composed mostly of hydrogen and helium. The Earth's atmosphere has not always contined the same gases. We believe that the atmosphere was f i r s t produced from the gases spewed out by erupting volcanoes soon a f t e r the Earth was formed. By studying the gases given off by volcanoes today, we can get an idea of the composition of the Earth's o r i g i n a l atmosphere. These volcanic gases consist mainly of water vapour (EL^O) and carbon dioxide (COg). We also believe that the e a r l y atmosphere contained two other gases, methane (CH^) and ammonia (NH^). As time progressed, chemical reactions a l t e r e d the atmosphere u n t i l i t contained mostly carbon dioxide and nitrogen. Venus appears to have t h i s type of atmosphere today. J u p i t e r and Saturn s t i l l have enormous amounts of methane and ammonia. More chemical reactions eventually removed most of the carbon dioxide from the atmosphere. Oxygen was f i r s t released in t o the a i r by simple l i f e forms such as b a c t e r i a . Gradually, the amount of oxygen increased u n t i l there was enough to support the type of l i f e forms we know today. At present, the f o s s i l evidence suggests that t h i s sudden increase i n the amount of oxygen occurred about 600 m i l l i o n years ago. 369 Today, green plants use the process of photosynthesis to remove carbon dioxide from the atmosphere, and release oxygen as a waste product. In turn, animals use the oxygen fo r r e s p i r a t i o n , and return carbon dioxide to the atmosphere. The Earth's atmosphere has changed i n the past, and today i t i s s t i l l changing. Since the s t a r t of the I n d u s t r i a l Revolution i n the eighteenth century, man has been burning ever increasing quantities of wood, coal, o i l and gas. The burning of these s o - c a l l e d " f o s s i l f u e l s " has added carbon dioxide to the atmosphere at a rate f a s t e r than green plants can remove i t . Since carbon dioxide has the a b i l i t y to "trap" heat energy from the sun, too much could have disastrous e f f e c t upon the Earth. I f the temperature were to r i s e too much, the polar i c e caps would melt, r a i s i n g the sea l e v e l and drowning most of our coastal c i t i e s . An extreme temperature r i s e could turn the Earth i n t o a l i f e l e s s desert. Fortunately, the s l i g h t increase i n the l e v e l of carbon dioxide i n our atmosphere so f a r , i s s t i l l too small to have any noticeable a f f e c t . The chart following t h i s n a r rative summarizes a number of f a c t s about the atmosphere. Like the i n t e r i o r of the Earth, the atmosphere i s also d i v i d e d i n t o l a y e r s . The d i v i s i o n between layers i s based upon changes i n temperature. As you might expect, the temperature decreases above the surface of the Earth, (why i s snow found on high mountains, even i n summer?), f o r the f i r s t few kilometres. However, at very high a l t i t u d e s the temperature of the atoms of gas i n the atmosphere i s nearly 1000°C! This occurs because at 37Q these a l t i t u d e s , the energy of the sun's rays i s very e a s i l y absorbed by the atoms of gas. Although the temeperature of the i d i v i d u a l atoms of gas i n t h i s part of the atmosphere i s very high, a man i n an unheated space s u i t i n the Earth's shadow would freeze to death! This would happen because the t o t a l number of atoms at t h i s a l t i t u d e i s very small. As a r e s u l t , even though they are at a very high temperature, there are not enough atoms to supply the man with enough heat energy to prevent him from f r e e z i n g . (Goody, Walker 1972). Questions 1. Why do you suppose that hydrogen and helium are found high i n the atmosphere and not close to the ground? .. (Hint: what happens to a helium balloon i f you l e t go of the string?) 3 7 1 THE ATMOSPHERE Height (km) 2500 2 0 0 0 1 5 0 0 1 0 0 0 Temp, (°c5 +927 +927 +927 +927 5 0 0 +922 400 +886 3 0 0 +720 2 0 0 +420 1 5 0 +237 1 0 0 - 3 3 9 0 - 6 3 80 - 8 7 7 0 - 6 3 60 - 1 3 5 0 - 3 40 - 1 3 30 - 3 8 2 0 - 6 3 10 - 4 3 0 +17 Temperature Layers Exosphere Gases I Pressure (kPa) Other Pacts Mostly hydrogen atoms (H)| Mostly helium w i t h hydrogen atoms. (He & H) Mostly oxygen Thermo sphere! atoms ^ w i t h helium ( 0 & He) Mesosphere Mos t l y • n i t r o g e n | StratosphereJ §no; g e n ( N 2 & 0 2 ) | Troposphere . 0 0 0 0 0 0 0 0 0 1 0 . 0 0 0 0 5 0 . 1 3 0 1 0 0 he exosphere s the r e g i o n rom which atoms of gas an escape rom the ~..-\:.:\. Earth ' s g r a v i t y i n t o space. andsat photographic s a t e l l i t e s o r b i t at 9 0 0 km a l t i t u d e . Some r a d i o waves r e f l e c t back to e a r t h from the ionosphere, a t 5 0 0 km. The aurorae o r northern l i g h t s are produced about 2 0 0 km. 9 9 * of the t o t a l mass of the atmosphere i s below 3 0 km 7 5 * of the t o t a l mass of the atmosphere i s below 1 0 km (Ordway, 1966) 372 NARRATIVE 4 Or i g i n and Development of the Earth As was mentioned i n the Introduction, we believe that our s o l a r system developed when a huge cloud of dust and gas contracted under the force of g r a v i t y . The o r i g i n a l planets may have been much lar g e r than those we see today. As the sun f l a r e d into l i f e , i t s heat may have "boiled o f f " much of the material forming the inner planets. This theory may explain why Mercury, Venus, Earth and Mars are quite small, rocky planets, while J u p i t e r , Saturn, Neptune and Uranus are large b a l l s of gas. (PlutO i s a mystery). The inner planets had most of t h e i r gas blown away by the sun, but the outer planets, being f a r t h e r away and therefore cooler, were able to keep t h e i r gas. Studies of rocks from the Moon and meteorites lead us to believe that the planets formed about 4.6 b i l l i o n years ago. The oldest rocks on Earth, located i n Greenland, a r e (Moorbath, 1 9 7 7 ) are about 3.8 b i l l i o n years o l d . What happened to the Earth between 4.6 and 3*8 b i l l i o n years ago? There are two possible theories to account f o r the missing 0.8 b i l l i o n years. 1 ) We know that rock on the Earth's surface i s -cuiti .r c o n t i n u a l l y being eroded away and reformed i n t o new rock. Perhaps t h i s process has a l t e r e d the Earth so much that there i s now none of i t s o r i g i n a l surface l e f t unchanged. 2) Possibly the Earth took a very long time to form. During t h i s time, the heat from the Earth's i n t e r i o r , part of which i s s t i l l molten, may have melted and.changed most 373. of the surface. At present, the second theory seems to be the most l i k e l y , since i t also accounts f o r the layers within the Earth. I f the Earth were once molten, i t would have been easy f o r the heavy i r o n to sink to the centre to form the core. The l i g h t e r rock could have moved to the surface to make the crust. The only problem i s : where did the heat come from to s t a r t the process? ' We know that, there are many atoms of radioactive elements, uranium f o r example, within the Earth. Radioactive elements are those which break down spontaneously, forming new, l i g h t e r elements. During t h i s process, heat i s released. Measurements have shown that t h i s heat i s enough to keep the i n t e r i o r of the planet very hot. Perhaps i n the past when the number of r a d i o a c t i v e atoms was much higher, the heat they produced was great enough to melt a large portion of the Earth, i n c l u d i n g the surface. Since that time, l i g h t e r rocks c o l l e c t e d high on the surface to create the continents. Heavier rocks c o l l e c t e d lower down, making the ocean basins. Volcanoes brought gases and water to the surface to produce the atmosphere and oceans. The surface of the Earth i s c o n t i n u a l l y changing. Weathering and erosion break down rocks and wash the pieces in t o the ocean. Mountain b u i l d i n g processes push up huge, areas such as the Rockies and the Himalayas. Even the continents appear to have moved during the b i l l i o n s of years since the Earth was made. Later i n t h i s u n i t , you w i l l 374 look at some, of these processes. (Press, Siever, 1978) Questions 1. Give two ways i n which the Earth would be d i f f e r e n t i f i t had formed cl o s e r to the sun. 2. Give two ways i n which the Earth would be d i f f e r e n t i f i t had formed i n an o r b i t between the o r b i t s of J u p i t e r and Saturn. 3. Give one piece of evidence which shows that t h e - i n t e r i o r of the Earth i s s t i l l very hot. INVESTIGATION 5 The Geological Time Scale The Earth appears to be about 4.6 b i l l i o n (4600 m i l l i o n ) years o l d . A very old person may l i v e to an age of 100 years. In a single human l i f e t i m e i t i s impossible to observe many of the changes which take place on the surface of the Earth. Mountain ranges are l i f t e d up and eroded away; enormous g l a c i e r s cover e n t i r e continents, then melt and vanish; continents d r i f t l i k e giant r a f t s across the face of the -Earth; a l l of these changes take place so slowly that we can not observe them d i r e c t l y . This exercise w i l l help you to appreciate the true length of the time periods which geologists use to measure the h i s t o r y of our planet. Purpose: to study the length of the Earth's l i f e t i m e , and some of the s i g n i f i c a n t events which have occurred. Procedure A . Make a p e n c i l mark near one. end of the paper tape. Label i t "Today, 0 years". Using a scale of 1.'mm = 1 m i l l i o n years 375 to measure backwards from "Today", mark and l a b e l each of the following events on your tape. Event Estimated Time, M i l l i o n s of Years Ago Today 0 End of l a s t i c e age i n B r i t i s h Columbia 0.008 (8000 years) Beginning of l a s t i c e age 1 F i r s t recognizable humans ( A f r i c a ) 2 F i r s t elephants 4-0 Last dinosaurs. Mammals become abundant 6 5 Formation of Rocky Mountains 7 0 Formation of west Coast Mountains 140 F i r s t Birds 180 F i r s t dinosaurs and mammals 2 2 5 F i r s t i n s e c t s 3 4 5 F i r s t land animals 400 F i r s t land plants 440 F i r s t animals with backbones ( f i s h ) 5 0 0 F i r s t known animals ( s o f t bodied) 1 2 0 0 Oldest plants found i n Canada (algae, Ontario) 2 0 0 0 F i r s t known plants (algae) 3 2 0 0 Oldest known Earth rocks (Greenland) 3 7 5 0 Oldest known Moon rocks 4500 Formation of Earth 4600? (Mathews et a l , 1978) 376.' B. Geologists have given names to the various parts of the Earth's l i f e . On your paper tape, mark the beginning and end of each of these eras. Name Cenozoic Era Mesozoic Era Paleozoic Era Precambrian Era Began, M i l l i o n s of Years Ago 70 225 600 4-600 Ended, M i l l i o n s of Years Ago s t i l l continuing 7 0 225 600 Questions ( 1. a) Copy the table below int o your notebook, then match the name of the correct era against each event. Event Era Humans Land plants appeared Rocky Mountains formed Dinosaurs F i r s t i n s e c t s West eoast Mountains formed Last i c e age F i r s t animals Formation of the Earth b) L i s t the names of the.four eras, then beside each write the number of years that i t l a s t e d . c) Calculate the percentage of the Earth's l i f e represented by each of the four eras. 2. I f one human generation takes 20 years, how many 377 generations have there been since the f i r s t recognizable humans appeared i n Af r i c a ? 3. a) Did early men ever use dinosaurs f o r food? b) Explain how you reached your answer to ( a ) . Conclusion What d i d you lea r n about the length of the Earth's l i f e t i m e i n t h i s investigation? NARRATIVE 6 Measuring the Age of the Earth During the nineteenth century, s c i e n t i s t s made many attempts to determine the age of the Earth. In 1899, John J o l y t r i e d to estimate the rate at which s a l t was being added to the world's oceans by r i v e r s . He thought that i f he knew how much s a l t was already i n the oceans, and how much new s a l t was being added each year, he could work back to f i n d a date when there was no s a l t i n the oceans. This, J o l y believed, would t e l l him the age of the Earth. His measurements and c a l c u l a t i o n s gave a r e s u l t of approximately 9 0 m i l l i o n years. About the same time, Lord K e l v i n studied the rate at which heat was being l o s t from the i n t e r i o r of the Earth as i t cooled. He believed that i f the Earth was once molten, and i f he knew the rate of heat l o s s , he could c a l c u l a t e how long i t would take f o r the Earth to reach i t s present temperature. He concluded that the Earth was 24- m i l l i o n years o l d . A number of other s c i e n t i s t s studied the rate at which 378. rock was being eroded from the continents, and deposited on the ocean f l o o r as sediment. By knowing t h i s rate, and measuring the thickness of sediments i n various parts of the world, they also t r i e d to ca l c u l a t e the Earth's age. Their estimates ranged from 17 m i l l i o n to 1600 m i l l i o n years. Although these methods were crude and inaccurate, they d i d serve one very useful purpose. A l l showed that the Earth was many times older than the few thousand years produced by studying the s c r i p t u r e s . In 1896 Henri Becquerel, a French s c i e n t i s t , discovered r a d i o a c t i v i t y . This i s a process i n which atoms of c e r t a i n elements break down spontaneously to form atoms of new, l i g h t e r elements. For example, Uranium with an atomic mass of 238 breaks down to form Lead 206. Using t h i s p r i n c i p l e , i n 1 9 0 5 an American chemist B. B. Boltwood attempted to determine the age of rocks. The method he devised i s b a s i c a l l y the same one we use today. In the process of ra d i o a c t i v e decay, atoms of some elements change spontaneously i n t o atoms of other elements. I t i s impossible to pre d i c t which i n d i v i d u a l atoms w i l l change (decay), but s c i e n t i s t s have observed that i n a c e r t a i n length of time, exactly h a l f of the atoms w i l l decay. In the next i d e n t i c a l length of time, h a l f of the remaining atoms w i l l decay. The process continues u n t i l a l l of the atoms have decayed. This time taken f o r h a l f of the atoms to decay i s c a l l e d the h a l f - l i f e of the element, and I t can be measured i n a laboratory. I f a geologist measures the amount of Uranium 238 and 379 the amount of Lead 206 i n a rock, and i f he knows the h a l f - l i f e of Uranium, he can c a l c u l a t e how much time has passed since the rock was formed. Figure 14-5 i s a graph showing two d i f f e r e n t radioactive decay rates. Follow the example shown as a dotted l i n e on the graph. I f 2 5 * of the Uranium atoms have changed to Lead, then the rock must be 1.6 b i l l i o n years old. (Peterson, Rigby 1 9 7 4 ) Questions 1 . A geologist measuring the amount of potassium and argon in. a rock found that 2 5 * of the potassium atoms had changed to argon. How old was the rock? 2 . In another rock, 5 0 * of the uranium atoms had decayed to lead. How old was the rock? 3 . What i s the h a l f - l i f e of the potassium-argon decay process? 4 . Explain why i t might be very d i f f i c u l t to f i n d the ages of very young rocks by using e i t h e r the potassium-argon or the uranium-lead methods. 5 . A method of radiometric dating used f o r very new material i s based on the decay of a s p e c i a l type of carbon c a l l e d carbon-14. While i t i s a l i v e , every l i v i n g organism takes i n small amounts of carbon-14 from the atmosphere. When the organism dies, the carbon-14 i n i t s body undergoes radio-s active decay and changes into nitrogen. The h a l f - l i f e of t h i s process i s 5 7 3 0 years. a) A piece of charred wood was found i n a lava flow. I f 5 0 $ of the o r i g i n a l carbon-14 atoms remained unchanged, how old was the lava? 38Q: 0 2 4 6 8 10 ,12 14 16 Time, B i l l i o n s of Years Figure 14-5. Decay rates f o r uranium-lead and potassium-argon processes. 3Q\ b) A f o s s i l l e a f was found i n some sedimentary rock. If 2 5 $ of i t s carbon-14- atoms remained undecayed, how old was the leaf? 6. a) In radiometric dating, why would i t be important to make sure that the rock samples had not been changed or disturbed since the rocks were formed? b) In a laboratory, a rock being dated by the uranium-lead method was a c c i d e n t a l l y contaminated with some excess uranium. Would the r e s u l t i n g i n c o r r e c t age be too old or too young? 7- Explain several reasons why the methods used by John J o l y and Lord K e l v i n to f i n d the age of the Earth were so inaccurate. 382 INVESTIGATION 8 Homologizing Bones S c i e n t i s t s believe that throughout the ages, new species of animals have developed from older species. The evidence f o r t h i s i s p a r t i c u l a r l y strong i n horses. Their ancestry can be traced through f o s s i l s , back to a small dog-siz e d mammal which l i v e d some 60 m i l l i o n years ago. (Otto 1977) In many ways, the s k e l e t a l bones of modern animals have the same general shape and p o s i t i o n as s i m i l a r bones i n ext i n c t animals. S k e l e t a l bones which appear i n s i m i l a r places i n d i f f e r e n t organisms are c a l l e d homologous structures. They are considered to be re l a t e d , even though t h e i r functions may be d i f f e r e n t . For example, the arm of a human has bones homologous with those i n the wing of a b i r d and the f o r e - l e g of a cat. I t i s even possible that animals with homologous structures may a l l be descended from a single common ancestor. In t h i s i n v e s t i g a t i o n , you w i l l be i d e n t i f y i n g . homologous structures i n the s k e l e t a l - bones of S a c r a l V e r t e b r a S c a p u l a S t e r n u m H u m e r u s L u m b a r V e r t e b r a - P e l v i s U l n a R a d i u s C a r p a l s M e t a c a r p a l s P h a l a n g e s Femur P h a l a n g e s Figure'146. Human skeleton with some of the bones l a b e l l e d . ( A f t e r Peterson & Rigby, 1974). I I Figure 14-8. Forelimbs of a number of animals. A- modern s e a l ; B- pterodactyl, an-extinct f l y i n g r e p t i l e ; C- modern bat; D- plesiosaur, an e x t i n c t swimming r e p t i l e ; E- e x t i n c t sabre-tooth t i g e r . ( A f t e r Peterson & Rigby, 1 9 7 4 ) . 386 various animals, both l i v i n g and e x t i n c t . Purpose: to i d e n t i f y and study homologous structures. Procedure A. Write the term homologous structures and i t s meaning i n your notebook. B. Various bones are i d e n t i f i e d on the skeleton of a human i n Figure 14-6. On a f u l l page diagram of Dimetrodon (Figure14-7) provided by your teacher, l a b e l each of the bones homolgous with the human bones. The Dimetrodon was a sail-backed mammal-like r e p t i l e which l i v e d l a t e i n the Paleozoic Era, about 2 5 0 m i l l i o n years ago. C. Your teacher w i l l supply you with a f u l l page diagram of Figure 14-8 showing the front limbs of a number of animals. I d e n t i f y and colour the homologous bones i n each limb. Colour the scapula red, the humerus blue, the radius yellow, the ulna green, the metacarpals and carpals purple, and the phalanges brown. D. For each of the diagrams i n Figure 14-8, write a few short sentences summarizing the reasons f o r the modifications i n each limb. For example, you might point out that the limb of the plesiosaur has been modified i n t o a f l a t f l i p p e r , s u i t a b l e f o r swimming i n the ocean. Questions 1. Copy the table below into your notes. Complete the second column with the name of the type of environment where each animal l i v e s . 387 Animal Environment Camel Whale Mountain sheep Monkey Mole Eagle Desert 2. Copy the table below into your notes. For each animal, give a reason f o r the p a r t i c u l a r body adaptation. Animal Adaptation Reason . Camel Wide f l a t f e et Do not sink i n sand Whale F l i p p e r s Mountain sheep Concave hoofs Monkey Grasping t a i l Mole Thick front claws Eagle Large wings Conclusion What have you learned about homologous structures i n t h i s investigation? NARRATIVE 9 The History of L i f e Why i s the h i s t o r y of l i f e u s u a l l y discussed during the study of geology rather than biology? This i s a question often asked by science students. A f t e r a l l , i s n ' t biology the science of l i f e , and geology the study of the Earth? Although i t may seem odd, l i f e h i s t o r y has always been c l o s e l y l i n k e d with Earth h i s t o r y . The only d i r e c t evidence of ancient l i f e i s provided by f o s s i l s - the remains of long dead animals and plants preserved i n layers of rock. Geology 388 and biology combine to form the science of paleontology, the study of ancient l i f e . In t h i s narrative, you w i l l learn about the progression of l i f e through the ages, from the single c e l l e d organisms of three b i l l i o n years ago to the almost countless v a r i e t y of l i f e forms today. S c i e n t i s t s generally agree that l i f e began i n the sea, about 3 or 4- b i l l i o n years ago. Just how t h i s happened i s not known, but we do have some ideas. In 1953 i n Chicago, an American chemist S. L. M i l l e r performed an experiment to show how the process may have started. In a glass apparatus, he heated a mixture of steam, methane, ammonia and hydrogen, gases:though to have been present i n the Earth's e a r l y atmosphere. Next he discharged e l e c t r i c a l sparks through the gas, t r y i n g to imitate l i g h t n i n g b o l t s . A f t e r a week of t h i s treatment, the water i n the apparatus had become deep red and cloudy. M i l l e r analysed the water and found that i t contained a complex mixture of amino acids, the basic chemical b u i l d i n g blocks of l i v i n g p r o t e i n . M i l l e r ' s apparatus d i d not create l i f e . I t d i d not even make pr o t e i n . A l l he d i d was manufacture the chemicals from which p r o t e i n i s made. I t i s an i n c r e d i b l y long step from a mixture of amino acid molecules to a l i v i n g c e l l which can reproduce i t s e l f . The process by which t h i s happened i s s t i l l a mystery which many s c i e n t i s t s are t r y i n g to solve. Regardless of the process by which i t was developed, we know that l i f e i n the form of b a c t e r i a and algae was well established three b i l l i o n years ago. At some unknown 389 Figure149. M i l l e r ' s apparatus .for simulating conditions on the early Earth. 3 9 0 time during the following two b i l l i o n years, more complex l i f e forms arose. The e a r l i e s t animal f o s s i l s we have are only 7 0 0 m i l l i o n years old. These are not the remains of the animals themselves (worms), but the traces of burrows and t r a i l s t h a t they made i n the ancient sea bottom. By 6 5 0 m i l l i o n years ago, i n the region we now know as A u s t r a l i a , j e l l y f i s h had developed. Then, s t a r t i n g about 600 m i l l i o n years ago, there was a tremendous increase i n the number and v a r i e t y of l i f e forms. No-one i s absolutely sure why t h i s occurred, but some s c i e n t i s t s have connected i t to a possible increase i n the amount of oxygen i n the atmosphere. During the Paleozoic Era, l i f e developed r a p i d l y . F i r s t came the t r i l o b i t e s and brachiopods, followed by sponges, c o r a l s and c r i n o i d s . About 4 - 5 0 m i l l i o n years ago, the f i r s t f i s h appeared. C a l l e d ostracoderms, they were not l i k e the f i s h we know today. Instead of being covered with scales, and having a skeleton made of bone, they were covered with a hard armour and had a skeleton made of c a r t i l a g e . The middle Paleozoic saw plants spread from the sea onto the surface of the land. With food now a v a i l a b l e on land, animals soon followed. The f i r s t of these were the amphibians. These appear to have evolved from a type of f i s h which had developed p r i m i t i v e lungs. Although they could move e a s i l y on land, the amphibians could never t r a v e l f a r from water since only i n water could t h e i r eggs develop and hatch. Towards the end of the Paleozoic Era, the f i r s t r e p t i l e s arose, developing from p r i m i t i v e amphibian ancestors. They 5 9 1 were no longer dependent on water since t h e i r eggs could survive being l a i d on land. About the same time, a large number of species which l i v e d i n the sea, inclu d i n g the t r i l o b i t e s , became e x t i n c t . During the Mesozoic Era, s t a r t i n g some 2 2 5 m i l l i o n years ago, the d i v e r s i t y and number of l i f e forms increased. In the seas, pelecypods, gastropods, .crinoids and ammonites were abundant, and the f i r s t p r i m i t i v e crabs appeared. On land, grasshoppers, beetles, dragonflies, termites and ants developed. In the rocks of t h i s era, the f o s s i l s of the f i r s t ancestral b i r d have been found. Named Archaeopteryx, i t had a r e p t i l e - l i k e skeleton and b i r d - l i k e feathers. The Mesozoic Era however, i s known by most people as the Age of Dinosaurs. For over 1 5 0 m i l l i o n years they were the dominant l i f e form on Earth. (Compare t h i s with mankind's 2 m i l l i o n years). Dinosaurs evolved forms which l i v e d i n a great v a r i e t y of h a b i t a t s . There were the huge swamp-dwelling Brontosaurs, and the meat-eating Tyrannosaurs. Plesiosaurs swam and hunted i n the oceans, while Pterosaurs gli d e d through the a i r . For t h e i r time, the dinosaurs were remarkably well equipped f o r s u r v i v a l . During most of t h e i r time on Earth, the dinosaurs shared the world with a group of small, hairy, active animals - the mammals. These are most I n t e r e s t i n g because i t was from t h i s source that humans eventually developed. Study of mammalian f o s s i l s shows that they evolved from r e p t i l e ancestors, and that t h e i r skeletons gradually changed t h e i r c h a r a c t e r i s t i c s from r e p t i l e to mammal over a period of 1 0 0 m i l l i o n years. 392 In the Mesozoic Era, many of the types of land plants that we. know today developed. F i r s t came the coniferous trees, followed by the flowering plants and trees. This tremendous d i v e r s i t y of plant l i f e provided food f o r the huge number of animals which how populated the Earth. Then came d i s a s t e r . We do not know whether i t took one thousand or ten thousand years, but over a very short period of time ( g e o l o g i c a l l y speaking), two-thirds of a l l the animal species on Earth became e x t i n c t . The dinosaurs disappeared from the land and the ammonites from the sea. We do not know what caused t h i s great dying. Some s c i e n t i s t s think that an unknown f a c t o r suddenly changed the climate Of the Earth. Others blame the massive e x t i n c t i o n on deadly r a d i a t i o n from a nearby supernova (exploding s t a r ) . Whatever the cause, the only animal species which survived seem to be those whose members had a mass of l e s s than ten kilograms. The l a s t 7 0 m i l l i o n years, the Cenozoic Era, completes the story of the development of l i f e to the forms we recognize today. Birds, horses, trees, spiders, f i s h and humans gradually evolved i n t o t h e i r modern species. Each animal or plant species adapted i t s e l f to the environment which s u i t s i t best, and where competition from other species i s l e a s t . Palm trees grow on t r o p i c a l i s l a n d s , while giant cedar trees grow on wet temperate coasts. Wolves hunt i n cool northern f o r e s t s , and t i g e r s prowl the jungles of A s i a . Each species struggles with i t s neighbour - the stronger survives and the weaker becomes e x t i n c t . (Casanova, 1957; McAlester, 1968). 593- • The story of the evolution of man has been pieced together from f o s s i l s discovered a l l over the world. I t i s f a r from c e r t a i n , but we think we now know the general d e t a i l s of our ancestry. Sometime between 4- and 10 m i l l i o n years ago, man and the other primate animals (monkeys, g o r i l l a s etc.) developed from a common mammal ancestor. By 3 m i l l i o n years ago, hominids (man-like animals) were 3 walking upright and had a br a i n size of about 4-50 cm . Within half a m i l l i o n years, ( 2 . 5 m i l l i o n years ago), they were s t a r t i n g to make t o o l s , and a larg e r b r a i n size was developing. About 1 . 5 m i l l i o n years ago, the f i r s t true man, Homo erectus appeared. Many stone t o o l s from t h i s time have been discovered. Not u n t i l 1 0 0 0 0 0 years ago d i d Homo sapiens appear i n the form of Neanderthal man. He was a stocky i n d i v i d u a l with a heavy s k u l l , s l i g h t l y f l a t t e r than ours. By t h i s time, b r a i n size had increased to.about 1400 cm . Only 40 000 years ago modern man, Homo sapiens sapiens a r r i v e d . His s k u l l i s le s s heavy than that of Nenderthal man, and his brai n s i z e i s s l i g h t l y smaller. About 10 0 0 0 years ago, man's t r a n s i t i o n from hunting to farming started, and the era of written h i s t o r y began. (Washburn, 1 9 7 8 ; Isaac, 1 9 7 9 ) . Where w i l l evolution take us from here? I f mankind i s to survive then we must remember the unbreakable r u l e : "Survival of the F i t t e s t " . I f the multiple problems of overpopulation and p o l i t i c a l s t r i f e are not solved, mankind w i l l have proven i t s e l f u n f i t . Then, l i k e the dinosaurs, mankind w i l l pass from the scene and another species w i l l 394 i n h e r i t the Earth. Questions 1. What determines the l o c a t i o n where a species l i v e s ? 2. Evolution appears to follow the rul e " s u r v i v a l of the f i t t e s t " . Use t h i s to explain why some species become ext i n c t , while others survive. INVESTIGATION 11; Sedimentary Rocks In Grade 8, you may have learned about weathering and erosion, the processes which wear down rock, then carry the broken pieces away. These broken pieces may be as large as boulders or as f i n e as f l o u r . A l l are known as sediment. I f the sediment i s c a r r i e d by water, i t eventually ends up 395 i n the ocean, where i t s e t t l e s to the bottom. Over the centuries, the sediment p i l e s up, and the weight of the sediment on top squeezes the sediment below into rock. In t h i s exercise you w i l l l e a r n to recognize and i d e n t i f y sedimentary rocks. Purpose: to recognize and i d e n t i f y sedimentary rocks. Procedure Part 1 The O r i g i n of Sedimentary Rocks A. Mix some sand, s i l t and water i n a 250 mL beaker. Allow the mixture to s e t t l e f o r a few minutes. Does the sand or the s i l t s e t t l e to the bottom f i r s t ? Does the material mixed with the water s e t t l e evenly or i n layers? B. Examine Figure 150. What i s the most noticeable feature of these sedimentary rocks? C. Copy the data table below int o your notebook. Mass of beaker and sand g Mass of beaker g Mass of sand g D. Use the platform balance to f i n d the mass of a 600 mL beaker. Record t h i s i n your data t a b l e . F i l l the beaker to a depth of 5 cm with dry sand. Find the mass of the beaker and sand, and record t h i s i n your data t a b l e . Subtract to f i n d the mass of the sand alone. E. Now you w i l l f i n d the mass of various depths of sand. Copy the following data table i n t o your notes. 396 P i g . 1 5 0 . Limestone i n south Wales. What clue t e l l s you that these rocks are sedimentary? (Photograph courtesy of A. Williams) F i g . 1 5 1 . Sandstone. This rock i s formed when grains of sand are squeezed and cemented together. 397 Depth of Sand Mass of Sand 5 cm 10 cm 100 cm (1 m) 1 km (1000 m) Record the mass f o r the 5. cm depth i n the second column of your ta b l e . M u l t i p l y to f i n d the weights of various depths of sediment. Does the weight at 1 km depth seem l i k e enough to s t a r t squeezing sediment into rock? Part 2 I d e n t i f y i n g Sedimentary Rocks Sedimentary rocks can form i n any of three d i f f e r e n t ways, mechanically, chemically, or. o r g a n i c a l l y . a) Mechanical o r i g i n . Rocks on the surface of the Earth are weathered and eroded. The r e s u l t i n g sediment s e t t l e s to the bottom of lakes and oceans where the pieces are squeezed and cemented together to form new sedimentary rock. The rocks are generally layered. I f animals or plants are trapped i n the sediment they form f o s s i l s . This type of rock i s named according to the si z e of the o r i g i n a l pieces of sediment. Name of Rock Type of Sediment Shale Sandstone Conglomerate Breccia Mud, clay, or s i l t Sand Rounded pebbles (gravel) Sharp, angular pebbles Descr i p t i v e adjectives may be applied to these names. For example, a sandstone may be described as "coarse" or " f i n e " . b) Chemical o r i g i n . The p a r t i c l e s i n these rocks are formed by chemical p r e c i p i t a t i o n or evaporation. The p a r t i c l e s are usually too f i n e to be seen, even with a hand 398 lens. Name of Rock O r i g i n and I d e n t i f i c a t i o n H a l i t e (Rock s a l t ) Limestone Dolomite Chert Sodium chloride produced by • •.. •.. . evaporation. Often has large c u b i c a l c r y s t a l s . I d e n t i f i e d by taste. Calcium carbonate, produced by evaporation or p r e c i p i t a t i o n . Fizzes with d i l u t e hydrochloric acid. Calcium magnesium carbonate, produced by p r e c i p i t a t i o n or evaporation. When powdered, f i z z e s with d i l u t e a c i d . Quartz ( s i l i c o n dioxide) p r e c i p i t a t e d from s o l u t i o n . Appears i n many forms, agate f o r example. c) Organic o r i g i n . These rocks are produced from the remains of l i v i n g organisms. Name of Rock O r i g i n and I d e n t i f i c a t i o n Limestone Coal Compressed and cemented sea s h e l l s and other marine debris from the ocean f l o o r . F i z z e s with d i l u t e a c i d . Layers of compressed and carbonized plant material. May be black or brown. Burns. F. Copy the data table below in t o your notebook. Sample Number Id e n t i f y i n g C h a r a c t e r i s t i c s Rock Name Examine each of the rock samples. In your data table, write down the sample number, the c h a r a c t e r i s t i c s you used to i d e n t i f y the rock, and i t s name. Part 3 Where Are Sedimentary Rocks Found? G. Examine the key on a geolog i c a l map of your l o c a l area. Which colours are used to represent sedimentary rocks? Name some places where sedimentary rocks may be found, and state which rocks may be found there. 599 Figure 153a What type of sediment i s being deposited at each location? 4-00 Q u e s t i o n s 1 . a ) C o p y t h i s t a b l e i n t o y o u r n o t e s : W a t e r S p e e d T y p e o f S e d i m e n t C a r r i e d N a m e o f R o c k F o r m e d F a s t M e d i u m S l o w b ) I n t h e s e c o n d c o l u m n , f i l l i n t h e t y p e o r t y p e s o f s e d i m e n t c a r r i e d b y e a c h w a t e r s p e e d : p e b b l e s , s a n d , o r s i l t . c ) I n t h e t h i r d c o l u m n , f i l l i n t h e n a m e o f t h e t y p e o f r o c k w h i c h w o u l d b e f o r m e d w h e n t h e s e d i m e n t s e t t l e d t o t h e b o t t o m : s h a l e , s a n d s t o n e , b r e c c i a o r c o n g l o m e r a t e . 2. E x a m i n e F i g u r e 153a s h o w i n g a v e r y f a s t r i v e r f l o w i n g i n t o t h e o c e a n . N a m e t h e t y p e o f r o c k , s a n d s t o n e , s h a l e o r c o n g l o m e r a t e w h i c h c o u l d b e f o r m i n g i n e a c h o f t h e a r e a s l a b e l l e d A , B a n d C . 5. I n w h a t s o r t o f c l i m a t e , h o t a n d d r y , o r c o o l a n d w e t , w o u l d h a l i t e b e m o s t l i k e l y t o f o r m ? C o n c l u s i o n I n t h i s i n v e s t i g a t i o n , ' w h a t d i d y o u l e a r n a b o u t s e d i m e n t a r y r o c k s ? I N V E S T I G A T I O N 14-V o l c a n o e s I n a n c i e n t t i m e s , t h e p e o p l e w h o l i v e d n e a r t h e i s l a n d o f V u l c a n o b e t w e e n I t a l y a n d S i c i l y t h o u g h t t h a t t h e y w e r e l o o k i n g a t t h e w o r k o f t h e g o d s . T o t h e m , t h e i s l a n d w a s t h e 401 chimney over a giant blacksmith's forge. V/hen the volcano erupted, they knew that Vulcan the blacksmith was at work, manufacturing thunderbolts f o r J u p i t e r the chief god, or beating out weapons f o r Mars the god of war. Although we no longer believe i n Vulcan, we are s t i l l impressed by the vi o l e n t beauty of volcanoes. In t h i s i n v e s t i g a t i o n , you w i l l study some volcanic landforms and the types of eruptions that produce them. Purpose: to study volcanoes and volcanic landforms. Procedure Part 1 Types of Volcano A. In Investigation 12 you learned that the temperature within the Earth i s much higher than the temperature at the surface. Twenty to f i f t y kilometres beneath the surface, the temperature i s high enough to melt rock. This molten rock i s c a l l e d magma. I f there i s a weak spot i n the Earth's crust, the magma can work i t s way to the surface and pour out to form a volcano. The molten rock which erupts from a volcano i s c a l l e d l a v a . Trace Figure 153b into your notebook. Label the magma, lava, and volcano. In your notes, write the words magma, lava, and volcano and t h e i r meanings. B. Examine Figures 1.54, 155 and 156. In your notes, make a sketch of the approximate shape of each volcano. T i t l e your sketch of Figure 1.54 as a cinder cone. T i t l e Figure 155 as "a composite cone or stratovolcano, and Figure 156 as a s h i e l d  volcano. Which type of volcano i s quite small with f a i r l y steep sides? Which i s large with long sloping sides that are not very steep? Which i s large with gentle slopes at the 4 - 0 2 F i g u r e 153b O p e r a t i o n of a v o l c a n o . 4-05 F i g . 156. On the skyline i s Mauna Loa, a giant s h i e l d volcano on the i s l a n d of Hawaii. 4-04-Figure 158. Internal structure of a stratovolcano. 4-05 base and steep slopes near the summit ("dished" sides)? C. F i l l a 250 mL beaker with a mixture of coarse sand and small pebbles (pea s i z e d ) . Pour the mixture slowly into a shallow pan so that a cone i s formed. Are the sides of the cone steep, "dished", or gently sloping? In your notes, sketch a side view of your cone.and l a b e l i t with the name of the type of volcano i t represents. Which type Of volcano i s formed by the eruption of s o l i d , lumpy pieces of rOck? Examine a piece of volcanic cinder and write a d e s c r i p t i o n of i t s appearance i n your notes. D. (Demonstration). Melt a block of p a r a f f i n wax i n a double b o i l e r (Figure 1 5 7 ) . Add a piece of wax crayon to make the wax more v i s i b l e . When the molten wax has cooled u n t i l i t i s j u s t about ready to s o l i d i f y again, pour i t slowly on to a small cone of sand on a large sheet of cardboard, so that a type of cone i s formed. Are tne sides of the model volcano steep, dished, or gently sloping? In your notes * sketch a side view of the model. and l a b e l i t with the name of the type of volcano i t represents. Which type of volcano i s formed by the eruption of very l i q u i d , f l u i d molten lava? E. A stratovolcano or composite cone i s formed by a l t e r n a t i n g . eruptions of s o l i d and l i q u i d m a t e r i a l . In your notes, make a sketch s i m i l a r to Figure158, showing the i n t e r n a l structure of a stratovolcano. (van Rose, 1974-) Part 2 Volcanic Landforms During past ages, volcanoes were found on many parts of the Earth. Although weathering and erosion have removed most of these, t h e i r existence can be seen by the many 4-06 volcanic landforms they l e f t behind. Many of these are located i n B r i t i s h Columbia. F. Read the descriptions below. From each d e s c r i p t i o n , make a l a b e l l e d sketch i n your notebook. a) Dyke: lava which pushed i n t o a v e r t i c a l crack i n the surrounding rock, then cooled. b) S i l l : lava which pushed into a hor i z o n t a l crack i n surrounding rock, then cooled. c) Columnar j o i n t i n g : lava which s p l i t into long, p i l l a r - l i k e columns when i t cooled. Perfect columns are si x - s i d e d . d) Lava tube: a tunnel through which lava once flowed. Lava cools and s o l i d i f i e s on the top and sides f i r s t . Molten l a v a s t i l l flows i n s i d e . I f the source of the lava i s cut of f , the l i q u i d lava i n s i d e drains away, leaving a long tunnel behind. e) Caldera: many volcanoes have a small depression on the top c a l l e d a c r a t e r . Sometimes under s p e c i a l circumstances, the ent i r e top of a volcano can collapse inwards and downwards to form a very large depression c a l l e d a caldera. Many calderas have f i l l e d with rainwater, forming lakes. f ) Black sand beach: (do not t r y to sketch). Where lava flows reach the ocean, the sudden cooling can sometimes cause the rock to be shattered i n t o sand. I f t h i s sand i s washed back onto the shore, i t can form a black sand beach. Exp l a i n why i t can be very p a i n f u l to walk barefoot on a black sand beach on a hot sunny day. g) Flood lavas: (do not t r y to sketch). In the past, 407 very large eruptions have flooded huge areas of the Earth with t h i n layers of lava. I f t h i s occurs many times, the t h i n layers can b u i l d on top of each other to p i l e up lava beds hundreds of metres th i c k . One such flow to the south of B r i t i s h Columbia, i n the states of Washington and 2 Oregon covered an area of over 50 000 km . (McKee, 1 9 7 2 ) (Francis, 1 9 7 6 ) . Questions 1. Ide n t i f y the type of volcano, cinder cone, stratovolcano or s h i e l d volcano shown i n each of the photographs i n . Figures 159 to 166. 2 . Name the volcanic landform (see Procedure F) shown i n each of the photographs i n Figures 167 to 171. 3. Figure 172 shows a f i s s u r e eruption by Kilauea volcano i n Hawaii. The lava i s pushing up through a crack i n the ground Name the volcanic landform being produced here. 4. Explain the dif f e r e n c e between lava and magma. 5. Figure 175 shows the areas of B r i t i s h Columbia covered by layers of lav a during the past 70 m i l l i o n years. a) What i s t h i s type of volcanic landform called? ? b) I f B r i t i s h Columbia has a t o t a l area of 9 5 0 600 knr, estimate the area covered by these lavas. 6. Figure 1 7 4 shows Olympus Mons, a huge volcano on the planet Mars. With a height of 24 000 metres, i t i s the large known volcano i n the solar system (Hartmann, Odell 1974). (Mount Everest i s 8843 m high). a)Does Olympus Mons appear .to be a cinder cone, stratovolcano or s h i e l d cone? 4-08 F i g . 159. The Canada-France-Hawaii telescope i s used by astronomers on top of t h i s volcano which i s 4180 metres high. F i g . 160. Many of the trees i n t h i s photograph have been k i l l e d by eruptions from t h i s volcano. 409 F i g . 162. These two small volcanoes are located i n c e n t r a l Oregon, U.S.A. 410 F i g . 164. Mauna Ulu, a volcano on the i s l a n d of Hawaii formed when lava erupted between 1 9 6 9 and 1 9 7 4 . 411 F i g . 166. Wizard Island i s a small volcano located i n Crater Lake National Park, Oregon, U.S.A. 4 1 2 Figure 167. Approximately 6600 years ago, following a v i o l e n t eruption, the summit of Mount Mazama collapsed downwards, leaving a huge hole on top of the mountain. The hole gradually f i l l e d with water to form Crater Lake, now located i n one of the most b e a u t i f u l National Parks i n Oregon, U.S.A. (Photograph courtesy of the U.S. Geological Survey). 4 1 3 Figure 168. A road cut exposed t h i s band of lava which forced i t s way through a crack i n the surrounding rock north of Squamish i n southern B r i t i s h Columbia. 414 Figure 1 6 9 . This volcanic landform i s a long tunnel on the i s l a n d of Hawaii. (Photograph courtesy of the Hawaii Natural History Association). 415 F i g . 1 7 1 . Hawaiian beaches l i k e t h i s can become so hot they can burn bare f e e t ! 416 F i g . 1 7 2 . Lava pouring out of a long crack i n the ground i s c a l l e d a " f i s s u r e eruption". (Photograph courtesy of the Hawaii Natural History Association;. 4 1 7 0 600 km i i i — i — i — i — ' Figure 1 7 3 . Areas of B r i t i s h Columbia covered by f l o o d lavas. Figure 174. Olympus Mons, a huge volcano on the planet Mars, i s three times as high as Mount Everest. Notice the caldera at the summit. (NASA photograph). 418 Figure 1 7 5 . Area of B r i t i s h Columbia which would be covered by Olympus Mons. 4 1 9 b) What i s the name f o r the huge depression at the summit of Olympus Mons? c) From Figure 1 7 5 , estimate the.land area covered by Olympus Mons. 7 . a) Before an eruption, the summit of a volcano frequently swells s l i g h t l y . What could cause t h i s ? b) Before an eruption, many small earthquakes are frequently f e l t i n the v i c i n i t y of a volcano. What could cause t h i s ? c) Explain two methods that s c i e n t i s t s could use to pr e d i c t a volcanic eruption. Conclusion What d i d you l e a r n about volcanoes i n t h i s investigation? INVESTIGATION 15 Volcano Location Volcanoes are found i n many areas of the Earth, i n c l u d i n g western Canada. In B r i t i s h Columbia, they are not very noticeable since none have erupted recent l y . In t h i s exercise you w i l l study the locations of the world's major volcanic areas. Purpose: to map the lo c a t i o n s of volcanic areas of the world. Procedure A. Use your a t l a s to locate the. volcanic areas l i s t e d below. On your map of the world, mark the p o s i t i o n s of i n d i v i d u a l volcanoes with a red X i Outline l a r g e r volcanic areas by shading them i n red. North America Mt. Baker (U.S.A.) Mt. Rainier (U.S.A.) Mt. Hood (U.S.A.) Mt. Shasta (U.S.A.) Lassen Peak (U.S.A.) Aleutian Islands (Alaska) Mt. G a r i b a l d i (B.C.) Mt. Downton (B.C.) Edziza Peak (B.C.) Aiyansh (B.C.) Central America & Caribbean Popocatapetl (Mexico) Lesser A n t i l l e s Islands Europe Mt. Vesuvius Mt. Etna Stromboli A f r i c a Kilimanjaro Mt. Kenya South America Aconcagua Chimborazo Cotopaxi Ojos d e l Salado (Delury et a l , 1978) 4-20 A s i a Kamchatka Peninsula K u r i l e Islands Japanese Islands Mt. Fujiyama P h i l l i p i n e Islands Celebes Islands New Guinea New Hebrides Islands Sumatra Krakatau Java Timor A t l a n t i c Ocean Iceland Azores Islands Ascencion Island St. Helena T r i s t a n da Cuhna Gough Island Bouvet Island P a c i f i c Ocean Hawaii Galapagos Islands Ruapehu (New Zealand) Ngaruhoe (New Zealand) Mt. Egmont (New Zealand) 4-22 Questions 1. Which ocean has a r i n g of volcanoes surrounding i t ? (This has sometimes been c a l l e d the "Ring of F i r e " ) . 2. a) Which ocean has a l i n e of volcanoes stretching down i t s centre? b) Use your a t l a s to f i n d the name of t h i s chain of volcanic' mountains. 3. a) Is the Earth's crust t h i c k e r under the continents or under the oceans? b) Would you expect to f i n d magma nearer the surface under an ocean or under a continent? c) Give one possible explanation f o r the f a c t that there are very few volcanoes i n the centres of continents. Conclusion What d i d you learn about volcanoes i n t h i s exercise? o 4-23 INVESTIGATION 17 Igneous and Metamorphic Rocks In Investigation 11 you studied sedimentary rocks, which are formed from layers of compressed sediment. In t h i s exercise, you w i l l study two other groups of rocks, igneous and metamorphic. Igneous rocks are formed from molten rock which has cooled and s o l i d i f i e d . They are generally divided into two sub-groups, volcanic and p l u t o n i c . Igneous rocks which form when molten rock cools r a p i d l y near the surface of the Earth are c a l l e d v o l c a n i c . Those which form when molten rock cools slowly, deep underground, are c a l l e d p l u t o n i c . Metamorphic rocks are formed when sedimentary or igneous rocks are changed from t h e i r o r i g i n a l nature by heat, pressure or chemical action deep underground. Purpose: to lear n to recognize and name igneous and metamorphic rocks. Procedure Part 1 Igneous Rocks A. Write the term igneous rock and i t s meaning i n your note-book. Examine a piece of broken igneous rock. Explain at l e a s t one clue which t e l l s you that the rock i s not sedimentary. B. Write the term plutonic rock and i t s meaning i n your notebook. Examine a piece of broken plutonic rock. I t i s made up of Int e r l o c k i n g c r y s t a l s . Are the c r y s t a l s large enough to be seen without a microscope? How many d i f f e r e n t colours of c r y s t a l s are there? When rock cools slowly, large c r y s t a l s are formed. 4-24-C. Write the term volcanic rock and i t s meaning in.your notebook. Examine a piece of broken volcanic rock. Can you see any cr y s t a l s ? Now examine the rock with a ten-power hand lens or stereo-microscope. Can you see any c r y s t a l s now? When rock cools r a p i d l y , small c r y s t a l s are formed. D. Igneous rocks are named according to the materials which make up t h e i r i n d i v i d u a l c r y s t a l s . Study the information below, then i d e n t i f y each of the rock samples you have been given. Organize your r e s u l t s i n t o a table s i m i l a r to the one i n Investigation 1 1 . Plutonic Rocks C r y s t a l Colour Rock Name mostly l i g h t c r y s t a l s l i g h t & dark, evenly mixed mostly dark c r y s t a l s granite quartz d i o r i t e gabbro Volcanic Rocks Ov e r a l l Colour Rock Name l i g h t grey medium very dark or black r h y o l i t e andesite basalt Unusual Cases - Description Rock Name volcanic glass l i g h t "frothy" volcanic glass f u l l of bubbles large c r y s t a l s embedded i n a background of microscopic c r y s t a l s obsidian pumice porphyry Part 2 Metamorphic Rocks E. Write the term metamorphic rock and i t s meaning i n your notebook. Examine a piece of broken metamorphic rock. Explain 425 one clue which t e l l s you i t i s neither sedimentary or igneous. F. Metamorphic rocks are named according to the type of sedimentary or igneous rock from which they are formed. In t h i s exercise you w i l l look at only four metamorphic xocks common i n B r i t i s h Columbia. Gneiss (pronounced "nice") i s formed when heat and pressure cause new c r y s t a l s to form, even though the rock i s not melted. The c r y s t a l s form i r r e g u l a r "bands" which may be confused with sedimentary l a y e r s . Marble i s metamorphosed limestone. I t f i z z e s with d i l u t e hydrochloric ac i d . Quartzite i s metamorphosed sandstone. Examination with a microscope shows that the grains of sand have been reshaped and "welded" together. Slate i s metamorphosed shale. I t may s p l i t into f l a t sheets. The d i r e c t i o n of the s p l i t s i s not the same as the d i r e c t i o n of the o r i g i n a l l a y e r s i n the shale however. Id e n t i f y each of the samples of metamorphic rock. Organize your r e s u l t s i n t o a neat t a b l e . (B.C. Dep't of Mines 1968) Questions 1. a) Where are plutonic rocks formed? b) What must happen to the overlying rock i n order f o r plutonic rocks to be exposed on the surface of the Earth? 2 . a) Does slow c o o l i n g or f a s t c o o l i n g cause the formation of large, c r y s t a l s ? b) Explain why rocks deep underground cool more slowly than rocks close to the surface. 426 F i g . 1 7 7 . Basalt i s a dark coloured volcanic rock. F i g . 1 7 8 . Granite i s a mostly l i g h t coloured plutonic rock. I t i s made up of large i n t e r l o c k i n g c r y s t a l s . 4-27 F i g . 1 7 9 . Gneiss i s a metamorphic rock common i n B r i t i s h Columbia. The c r y s t a l s l i n e up into i r r e g u l a r "bands". 428 3. How are the bubbles formed i n a piece of pumice? 4. A piece of obsidian has no c r y s t a l s - Would you expect obsidian to have cooled very r a p i d l y or very slowly? 5- Andesite i s named a f t e r a range of volcanic mountains i n South America. Use your a t l a s to f i n d the name of these mountains. Conclusion What d i d you learn about rocks i n t h i s investigation? NARRATIVE 18 The Rock Cycle You may r e c a l l work on the water cycle i n previous years. Ocean.water evaporates into the atmosphere,' f a l l s on the land as r a i n , and eventually reaches the ocean again. 0 Water can take anywhere from several hours to several thousand years to move through t h i s c y c l e . In'a fashion s i m i l a r to water, rocks may also move through a c y c l e . However, the rock cycle (Figure 180) may take from several hundred to several b i l l i o n years. Sooner or l a t e r , the processes of weathering and erosion grind a l l rock i n t o sediment. As you learned i n Investigation 11, t h i s sediment may become sedimentary rock. Examine Figure 148 c a r e f u l l y . The arrows show the various paths that sedimentary rock can take before becoming sediment again. Po s s i b l y i t may be buried so deeply that heat and pressure convert the sedimentary rock i n t o a metamorphic rock, s l a t e . I f the sl a t e i s buried deeply enough, i t may become gneiss. Possibly the gneiss w i l l melt to form a magma, which may 429 ROCK Figure 180. The rock c y c l e . 4-JO cool underground to form plutonic igneous rock. On the other hand, the magma may r i s e to the surface and erupt as lava to b u i l d a volcano. Eventually, the volcano w i l l be weathered and eroded to sediment, and the rock w i l l have come f u l l c i r c l e . In Figure 180, the arrows show a number of "shortcuts" which can be made across the c i r c l e . This en t i r e sequence i s known as the rock cycle. The theory i s us e f u l , but i n p r a c t i s e , very few rocks have t r a v e l l e d around the f u l l c i r c l e . Even the 4-.6 b i l l i o n year l i f e of the Earth has not provided enough time f o r a l l rocks on Earth to have completed the f u l l c y c l e . (Ernst, 1969; McKee, 1972). Questions 1. Describe a sequence of events which could turn igneous rock into sedimentary rock. 2. Describe a sequence of events which could change igneous rock to metamorphic rock. 3. Explain how a plutonic rock could become a volcanic rock. 4-30 cool underground to form plutonic igneous rock. On the other hand, the magma may r i s e to the surface and erupt as lava to b u i l d a volcano. Eventually, the volcano w i l l be weathered and eroded to sediment, and the rock w i l l have come f u l l c i r c l e . In Figure 180, the arrows show a number of "shortcuts" which can be made" across the c i r c l e . . i This entire sequence i s known as the rock cycle. The theory i s us e f u l , but i n p r a c t i s e , v v e r y few rocks have t r a v e l l e d around the f u l l c i r c l e . Even the 4 - . 6 b i l l i o n year l i f e of the Earth has not provided enough time f o r a l l rocks on Earth to have completed the f u l l c y c l e . (Ernst, 1 9 6 9 ; McKee, 1 9 7 2 ) . Questions 1. Describe a sequence of events which could turn igneous rock into sedimentary rock. 2 . Describe a sequence of events which could change igneous rock to metamorphic rock. 3. Explain how a plutonic rock could become a volcanic rock. 4-31 INVESTIGATION,20 Recording Earthquakes Each year, the world i s shaken by over one m i l l i o n earthquakes. Fortunately, most Of these are too small to be noticed. Even small earthquakes however, are useful to s c i e n t i s t s . To lea r n more about the i n t e r i o r of the Earth, they t r y to record the l o c a t i o n and magnitude of as many earthquakes as possible . The instrument used f o r recording earthquakes i s c a l l e d a seismograph. Purpose: to lea r n how a seismograph operates. Procedure A. Place your textbook near the edge of your desk, with a piece of paper underneath i t (Figure 181). P u l l the paper slowly. Does the book move with the paper? Now give the paper a quick jerk. Does the book move as much as the paper? Is i t possible to jerk the paper out from under the book, without moving the book? We say that the book has i n e r t i a . I n e r t i a means resistance to r a p i d changes i n movement. Write t h i s term and i t s meaning i n your notebook. Objects with a l o t of mass have a l o t of i n e r t i a . B. Set up the model seismograph (Figure 182). Does the part of the seismograph which holds the pen have i n e r t i a ? Shake the table sideways to simulate an earthquake. Does the penholder r e s i s t moving at f i r s t ? Does the table move under-neath the pen? C. P u l l the paper tape slowly underneath the pen. Describe the shape of the l i n e made on the paper. What sort of a record does a seismograph make when no earthquake i s happeni 432 Figure 182. Demonstration model seismograph. 433 D. P u l l the paper tape while shaking the table very l i g h t l y . What sort of record does a seismograph make during a small earthquake? E. P u l l the paper tape while shaking the table more strongly. What sort of record does a seismograph make during a,strong earthquake? F. I f possible, paste the records from Procedures C, D, and E into your notebook. Label each as no, weak, or strong earth-quake. Questions 1. a) What i s i n e r t i a ? b) How does a seismograph use i n e r t i a to help i t record an earthquake? 2. The seismograph model you used recorded only sideways motion during the earthquake. How would you place the model to record back and f o r t h motion? 3. Design a seismograph to record up and down motion of the ground. Make a l a b e l l e d sketch of your design. Conclusion • How does a seismograph record earthquakes? INVESTIGATION 22 Earthquake Patterns In Narrative 19 you learned that earthquakes occur where s t r a i n forces along f a u l t s i n the Earth's crust are suddenly released. In t h i s exercise you w i l l determine from 434 earthquake locations just where major f a u l t s are located near B r i t i s h Columbia, and elsewhere around the world. Purpose: to locate major f a u l t zones i n B r i t i s h Columbia and the world. Procedure Part 1 Earthquakes i n Western Canada A. Write the words earthquake and f a u l t and t h e i r meanings i n your notes. B. Between 1 8 9 9 and 1 9 7 0 there were 5 2 earthquakes on the west coast of Canada having Richter magnitudes greater than 6 . 0 . A l i s t of these and t h e i r locations i s given below. On a copy of the B r i t i s h Columbia map in.Figure 1 8 3 , p l o t each of these p o s i t i o n s with a small X. 8 or greater 7 to 8 Major Earthquakes of Canada on the West 1 8 9 9 - 1 9 7 0 Coast atitude Longitude Magnitude Latitude Longitude 60°N 140°W 7 to 8 50°N 1 2 9 . 8°W 60 142 4 9 . 9 128 5 3 . 6 1 3 3 . 2 4 9 . 8 126 . 7 59 141 4 9 - 9 124 . 9 5 7 . 4 1 3 7 . 1 4-7 .5 1 2 2 . 6 5 5 - 9 136 4 7 . 1 1 2 2 . 9 5 4 . 5 134 46 . 9 1 2 2 . 8 5 3 . 2 , 1 3 3 - 7 48 . 7 128 . 5 5 3 . 9 1 3 2 . 1 48 . 4 1 3 0 5 2 . 8 1 2 9 . 5 6 to 7 5 9 1 3 9 . 3 5 1 . 7 1 3 1 . 5 5 8 . 9 V 1 3 9 5 1 . 8 1 2 9 . 2 5 9 . 5 1 3 0 5 0 . 9 131 58 1 3 6 435 Magnitude Latitude Longitude Magnitude Latitude Longitude 56°N 156.2°W 6 to 7 50.4°N 1 2 9 . 5°W 54 152.5 50.1 128.1 55.5 132 50 127 , 52.9 151.9 49.7 132 52.5 132.1 49.5 130.1 52.4 132.1 49.1 129-9 5 2 131.6. 49.5 129.1 52 131 49-5 129.2 5 1 . 5 130.8 48.9 130 51.1 130 48.7 129.5 50.8 130.8 48.5 128.9 50.7 130.9 48.4 129.2 50.5 129.6 47.5 124.2 C. On your map, draw a s t r a i g h t heavy l i n e showing the probable l o c a t i o n of a major f a u l t zone o f f the west coast. Label t h i s l i n e as the "Queen Charlotte F a u l t " . Draw another l i n e to show the possible l o c a t i o n of a f a u l t across northern Vancouver Island. Label t h i s l i n e as the "Nootka Fault" Which major U.S. c i t y i n the map area i s subject to earthquake hazard? ( I f necessary, use your a t l a s ) . (Milne 1976) Part 2 Earthquakes Around the World D. Throughout h i s t o r y , hundreds of thousands of people have been k i l l e d by earthquakes. Most of these deaths were caused by the collapse of poorly constructed b u i l d i n g s , or by s t a r v a t i o n and disease following the d i s a s t e r . A l i s t of some of these major earthquakes i s given below. Pl o t the 436 Figure 183. The po s i t i o n s of B r i t i s h Columbia earthquakes should be p l o t t e d on a copy of t h i s map.. 438 p o s i t i o n of each of these with a small X on a copy of the world map i n Figure 184. Major H i s t o r i c a l Earthquakes Year Location Deaths Richter Magnitude 526 Antioch, S y r i a 250 000 unknown 856 Corinth, Greece 45 000 unknown 1 2 9 0 C h i h l i , China 100 000 unknown 1295 Kamakura, Japan 30 000 unknown 1531 Lisbon, Portugal 30 000 unknown 1750 Hokkaido, Japan 137 000 unknown 1737 Calcutta, India 3 0 0 000 unknown 1 7 5 5 Lisbon, Portugal 60 000 unknown 1755 Northern Iran 40. 000 unknown 1797 ; Quito, Ecuador 41 000 unknown 1822 Aleppo, S y r i a 22 000 unknown 1868 Peru & Ecuador 40 000 unknown 1906 San Francisco, U.S.A. 4 5 2 8.3 1906 Valpariso, C h i l e 20 000 8.6 1908 Messina, I t a l y 83 000 7-5 1 9 2 0 Kansu, China 100 000 8.6 1923 Tokyo, Japan 99 3 3 0 8.3 1927 Nan-shan, China 200 000 8.3 1935 Quetta, Pakistan 30 000 7.5 1 9 3 9 C h i l i a n , C h i l e 28 000 8-3 1 9 5 9 Erzincan, Turkey 30 000 7-9 1946 Courtenay, B.C. 0 7-3 1 9 4 9 Queen Charlotte I s . , B .C. 0 8.0 -1950 Assam, India 1 5 3 0 8.7 439 Year Location \ Deaths Richter Magnitude 1954 Northern A l g e r i a 1 2 5 0 6 . 8 1 9 5 6 Northern Afghanistan 2 0 0 0 7 . 7 1 9 6 0 Agadir, Morocco 12 0 0 0 5 - 8 1 9 6 0 Southern Chile 5 0 0 0 8 . 3 1 9 6 5 Skopje, Yugoslavia 1 1 0 0 6 . 0 1964- Valdez, Alaska 114 8 . 5 1 9 6 6 Eastern Turkey 2 5 2 0 6 . 9 1 9 6 8 Northeastern Iran 12 0 0 0 - 7 . 4 1 9 7 0 Northern Peru 6 6 7 9 4 7 . 7 1 9 7 2 Managua, Nicaragua 5 0 0 0 6 . 2 1 9 7 6 Guatamala 22 7 7 8 7 . 5 1 9 7 6 New Guinea (West I r i a n ) 4-4-3 7 . 1 1 9 7 6 Indonesia ( B a l i ) 5 0 0 5 . 6 1 9 7 6 Tangshan, China 6 5 5 2 3 5 8 . 2 1 9 7 6 P h i l l i p i n e I s . 8 0 0 0 7 . 8 1977 Bucharest, Romania 1 541 7 . 5 1977 Northwest Argentina 1 0 0 8 . 2 1 9 7 8 Tabas, Iran 25 0 0 0 7 . 4 (Delury 1 9 7 8 ) E. Draw a heavy l i n e on your map to show the major "earth-quake b e l t " through North and South America. Draw s i m i l a r l i n e s through southern Europe and, Turkey to India, and through Japan southwards. F. There are many earthquakes each year i n areas where few people l i v e . Draw l i n e s on your map i n d i c a t i n g these areas. 4-4-0 P a c i f i c Ocean Area A t l a n t i c Ocean Area East P a c i f i c Ridge Chi l e Rise Aleutian Islands Kamchatka Peninsula K u r i l Ridge Marianas Trench New Hebrides Cocos Ridge Kermandec Trench P a c i f i c - A n t a r c t i c Ridge Mid-Atlantic Ridge At l a n t i c - I n d i a n Ridge South Sandwich Trench Puerto Rico Trench Windward Islands Indian Ocean Area Southwest Indian Ridge Carlsberg Ridge Mid-Indian Ridge Southeast Indian Ridge Andaman Islands Questions 1. Do earthquakes seem to occur more i n some areas than i n others? 2 . Is there any s i m i l a r i t y between the earthquake zones and the volcanic areas you p l o t t e d i n Investigation 1 5 ? 3. a) Should people l i v e i n active earthquake zones? b) Do you l i v e i n a major earthquake hazard area? ( I f necessary, look at Figure 183. Conclusion What have you learned about earthquakes i n t h i s exercise INVESTIGATION 24-The Ocean Floor Most geologists believe that l i f e on Earth originated i n the oceans. In a sense, the ocean i s man's o r i g i n a l home. And yet, even today we know very l i t t l e about them. The two-thirds of our planet's surface which l i e s beneath the 4-4-1 ocean i s l a r g e l y unexplored. In t h i s exercise, you.will learn a l i t t l e about the shape of the f l o o r of the North A t l a n t i c Ocean. Purpose: to draw a p r o f i l e of the f l o o r of the North A t l a n t i c Ocean, and to name some of i t s features. Procedure A. Look at a map of the f l o o r of the North A t l a n t i c Ocean. Is i t f l a t or mountainous? Are most of the mountains generally located i n the centre of the ocean or along the edges? Where are the deep f l a t areas generally located? Where are the shallow f l a t areas generally located? B. To get a better idea of what the ocean f l o o r looks l i k e , you w i l l next draw a cross-section. Cut a piece of 1 mm graph paper lengthwise into three pieces. Tape the ends together, l i n i n g up the markings, so you have a graph about 85 cm long and 7 cm high. (Figure 185). C. Draw axes on your graph paper so that the horizontal axis represents the ocean surface, and the v e r t i c a l axis represents depth. Use a scale of 1 cm = 100 km on the hor i z o n t a l axis, and 1 cm = 1000 m on the v e r t i c a l axis. (Figure 185). D. The table below represents distance and depth across the A t l a n t i c from North America to Europe. Pl o t each point on your graph paper, and connect the points i n order with s t r a i g h t l i n e s . 4-42 PISTANCC (km) 6 200 0 ( O O O 2000 J O O O 4.000 SOOO 6 OOO 70OO 4000 0 O O F i g u r e 185- Taping together graph paper f o r a c r o s s -s e c t i o n of the A t l a n t i c Ocean F l o o r . 8 mm Steepness on the c r o s s - s e c t i o n a 0 OJ 80 mm A c t u a l steepness F i g u r e 186. Demonstrating the exaggeration of steepness on the c r o s s - s e c t i o n of the A t l a n t i c Ocean f l o o r . P o i n t D i s t a n c e ( k m ) D e p t h ( m ) 1 0 o 2 120 200 5 200 2700 4 400 5700 5 . 440 4400 6 480 4400 7 4 9 0 5 7 0 0 8 5 0 0 4400 9 560 4600 10 640 4600 11 660 1800 12 680 1800 1 3 690 5700 14 7 0 0 2700 1 5 7 2 5 4600 16 1 3 7 5 4800 1 7 1390 5 7 0 0 18 1400 4800 1 9 1850 4900 20 1875 5 7 0 0 21 1890 4600 22 2075 4400 2 3 2090 1800 24 2100 4400 2 5 2210 4400 26 2420 4000 2 7 2440 5500 P o i n t D i s t a n c e ( k m ) D e p t h ( m ) 28 2450 4000 2 9 2850 3 5 0 0 50 2900 3100 5 1 2960 2700 3 2 2975 1800 55 5060 . 2200 34 5 0 7 5 4000 35 5100 2400 36 5 1 9 0 1800 57 5 2 0 0 2 9 0 0 38 5525 3 5 0 0 59 5540 2700 40 5550 5 5 0 0 41 5625 5700 42 5650 2400 45 5640 5 7 0 0 44 4025 4000 45 4055 9 0 0 46 4050 2 7 0 0 47 4090 1800 48 4100 + 5 0 0 49 4110 2200 5 0 4190 2 7 0 0 4225 4100 52 4 7 5 0 4800 55 4760 5 1 0 0 54 4 7 7 0 5100 4-4-4-Point Distance (km) Depth (in) Point Distance (kin) Depth (m) 5 5 4-780 4-600 61 5 6 2 5 4-600 5 6 4-825 4-4-00 62 5 6 7 5 4 - 0 0 0 5 7 5 1 5 0 4 - 2 0 0 6 3 5 8 7 5 5 7 0 0 5 8 5 1 6 0 ' 2 0 0 64- 6 0 5 0 2 7 0 0 5 9 5 1 7 0 4 - 2 0 0 6 5 6 0 7 5 2 0 0 60 5 3 9 0 4-4-00 6 6 6100 0 (data a f t e r Press, Siever 1 9 7 8 ) Just as there are s p e c i f i c names fo r surface features the land, such as mountain, v a l l e y , plateau etc., there are names f o r features on the ocean f l o o r . Read the descriptions below, then l a b e l an example of each on your cross-section. a) Continental shelf: shallow area extending seaivard from the shoreline. b) Continental slope: steep area extending from the edge of the continental s h e l f . c) Continental r i s e : gentle slope between the continental slope and the deep ocean f l o o r . d) Abyssal p l a i n : f l a t surface oh the deep ocean f l o o r . e) Abyssal h i l l : r e l a t i v e l y small h i l l , u sually l e s s than 1 0 0 0 m high on the deep ocean f l o o r . f) Seamount: mountain, probably volcanic, with a steep slope and a small summit, us u a l l y more than 1 0 0 0 m high. g) Guyot: flat-topped seamount. h) Mid-Atlantic Ridge: a broad arch occupying approximately the c e n t r a l hal f of the ocean. i ) Mid-Atlantic R i f t : a deep v a l l e y near the crest of the Mid-Atlantic,Ridge. 4-4-5 F. When something can be folded i n half so that the opposite sides match, i t i s c a l l e d symmetrical. Fold your cross-section i n h a l f at the Mid-Atlantic R i f t , then hold i t up to the l i g h t so you can see the l i n e s . 3/ou drew. Is the shape of the f l o o r of the A t l a n t i c Ocean approximately symmetrical? G. The cross-section you drew greatly exaggerates the steepness of parts of the ocean f l o o r . To compare the actual steepness with the graphical steepness, draw two right-angled t r i a n g l e s using the measurements given i n Figure 186. T i t l e one -triangle, "Actual Steepness of the Continental Slope", and the other t r i a n g l e , "Steepness of the Continental Slope as Shown on Graph". Questions 1. What i s the approximate length of the Mid-Atlantic Ridge (Use your a t l a s ) . 2. On which part of the ocean f l o o r i s most of the sediment from r i v e r s deposited? 3. Describe two d i f f e r e n t ways In which geologists might obtain rock sample from the ocean f l o o r . Conclusion What d i d you l e a r n about the f l o o r of the A t l a n t i c Ocean i n t h i s investigation? 4-4-6 INVESTIGATION 26 Continental D r i f t For many years a f t e r the South A t l a n t i c Ocean was explored, earth s c i e n t i s t s were puzzled by i t s shape. They noticed the curious s i m i l a r i t y i n the shapes of the c o a s t l i n e s of A f r i c a and South America, and wondered i f they might once have been joined. From t h i s idea grew the theory of continental d r i f t . This theory states that at one time i n the d i s t a n t past, a l l the continents were joined together into one huge "supercontinent". Then the super-continent broke apart and the continents slowly moved or " d r i f t e d " to t h e i r present postion on the globe. In t h i s exercise you w i l l check on just how c l o s e l y the four continents surrounding the A t l a n t i c Ocean f i t together. Purpose: to f i t North and South America, Europe and A f r i c a together, and to determine the true edge of each continent. Procedure A. Figure 187 shows the outline of each continent along the present day sea l e v e l . From a f u l l page copy of Figure 187, use s c i s s o r s to cut- out each continent and Greenland. 1 S t a r t i n g with the continents i n the same general postion as they appear today, s l i d e them together u n t i l they f i t l i k e a jigsaw puzzle. The pieces w i l l not f i t p e r f e c t l y , but do the best you can without overlapping. When you have found the best f i t possible, glue the pieces on to a sheet of 1 cm graph paper. B. Using your jigsaw from Procedure A, count the approximate number of square centimetres of "gap" l e f t between the . 4-4-7 continents. Write t h i s number i n your notebook. C. Figure 188 shows the outline of the continental shelf surrounding each continent. Repeat Procedure A v/ith the f u l l page copy of t h i s diagram. D. As i n Procedure B, count the number of square centimetres of gap l e f t between your continents. Write t h i s number i n your notebook.. • Which f i t more c l o s e l y together, the edges of the continents at present day sea l e v e l , or the edges of the continental shelves? Would a supporter of the theory of continental d r i f t choose the present day sea l e v e l , or the edge of the continental shelf as the "true" edge of each continent? Questions 1. V/hat made s c i e n t i s t s f i r s t think that North America, South America, Europe and A f r i c a might once have been joined? 2. How d i d the discovery of the continental shelves help support t h i s theory? 3 . a) During the i c e age, 10 000 years ago, was the sea l e v e l higher or lower than i t i s today? b) Is there any reason why the present day sea l e v e l should be considered to be the true edge of the continents? 4-. a) What is, the name of the ridge of mountains running down the middle of the A t l a n t i c Ocean? b) Which type of rock are these mountains made of, sedimentary, plutonic or volcanic? c) I f the surface of the Earth i s ' s p l i t t i n g " along t h i s ridge, how i s the gap being f i l l e d ? 448 449 Figure 188. Outlines of continents along the edges of the continental shelves. 4-50 Conclusion . What d i d you learn about how well the four continents surrounding the A t l a n t i c Ocean f i t together? INVESTIGATION 27 Sea Floor Magnetism How does a compass work? You probably know already that the Earth acts l i k e a giant magnet, and that a compass needle points to the north and south magnetic poles. Did you know that the magnetic poles move? Their positions a c t u a l l y change s l i g h t l y from year to year. At present, the north magnetic pole i s located on Bathurst Island i n the Canadian a r c t i c . I t s p o s i t i o n i s about 1600 kilometres away from the north geographic pole. Ove m i l l i o n s of years, the magnetic f i e l d of the Earth has changed considerably. The changes have been studied by s c i e n t i s t s , and they can t e l l us much about the movements of the Earth's crust. In t h i s exercise, you w i l l study some of the r e s u l t s of these studies. Purpose: to study changes i n the Earth's magnetic f i e l d recorded on the ocean f l o o r . Procedure Part 1 Layers of Lava A. Which side of your room i s north? Examine your compass. How i s the needle marked to show which end points north? B. Look at the p i l e of boxes put out for.you to work with. . Each box represents an old lava flow which cooled and hardened. When lava hardens, the i r o n minerals i n the rock 4-51 South end of room Young Old ft North end of room Figure 189. P i l e of boxes representing layers of cooled and hardened lava. Figure 190. L i f t i n g and spreading cards to represent l a v a spreading from a midocean ridge. 4-52 are magnetized.' i n the d i r e c t i o n of the Earth's magnetic  f i e l d . By t e s t i n g layers of lava, s c i e n t i s t s can t e l l where the Earth's magnetic poles were located, m i l l i o n s of years ago. Copy Figure 1 8 9 into your notes. Use your compass to te s t each model layer of lava (each box). On your diagram, l a b e l the magnetic north and south pole d i r e c t i o n s f o r each la y e r . How does the d i r e c t i o n of the Earth's magnetic poles change over long periods of time? C. What you found with the model lava layers i s the same as what geologists have found i n layered rocks i n many parts of the world. What do you think may have happened to cause these r e s u l t s ? Part 2 Undersea Volcanoes D. (Demonstration). You have seen how lava layers can t e l l the d i r e c t i o n of the Earth's magnetic f i e l d m i l l i o n s of years ago. Now you w i l l see what happens when volcanoes erupt lava along a midocean ridge. Your teacher w i l l l i f t p a i r s of cards up between a p a i r of tables (Figure 1 9 0 ) , representing eruptions of lava. The d i r e c t i o n of the magnetic f i e l d i s recorded, on each card. E. In your notebook, draw a diagram of the r e s u l t i n g pattern of cards, as seen from above. Record the d i r e c t i o n of the magnetic f i e l d i n each part of the pattern. Where are the youngest rocks located? Where are the oldest rocks located? I f the processes of ocean f l o o r spreading and magnetic re v e r s a l s continue, how w i l l the pattern look i n the future? Part 3 The Ocean Floor F. Geologists have c o l l e c t e d age and magnetic data from rocks 453 on the ocean f l o o r near the Mid-Atlantic Ridge, southwest of Iceland.. On a f u l l page copy of Figure 1 9 1 , mark the data i n the table below. Stations 1 and 2 have already been plo t t e d as examples. Magnetic F i e l d D i r e c t i o n s on the Ocean Floor S t a t i o n Latitude Longitude Magnetic Symbol Age ( M i l l i o n s F i e l d of Years) D i r e c t i o n 1 58.8°N 29°W Normal 0 8 2 58.5 29 . Reversed X -3 58.8 50 Reversed X -. 4 59 51-9 Reversed X -5 59 51 Normal 0 Present 6 59 29.6 Reversed X -7 59 29 Normal 0 -8 58.9 27.5 . Normal 0 -9 59 28 Reversed X -10 59.2 51 Normal 0 . -11 59.2 30 Normal 0 -12 59 . 7 52 Normal 0 8 15 . 59.8 5 0 . 7 Reversed X _ . . 14 59-5 50 Normal 0 Present 15 59-5 2 9 Reversed X -16 59.4 .28 Normal 0 8 17 60 32 Reversed X -18 60 31.5 Normal 0 8 19 60 30.8 Normal 0 •c 20 60 29-5 Normal 0 Present 21 60 28.2 Reversed X — Station Latitude Longitude 22 59-8°N 27-8°M 2 3 60 27 24 59.7 27 2 5 60 26.2 26 60.5 52 27 60.5 51 28 61 31.5 29 60.6 51 30 61 5 0 31; 60.8 29 52 60.5 28 55 61 26.7 34 60.5 27 55 60.8 26 36 60.5 26 57 61 2 5 38 61.7 50 59 61.5 29.8 40 61.7 29 41 61.5 27-5 42 61.2 27 43 61.5 25 44 62 2 9 45 62 28.5 46 62 27.2 47 62 26.5 Magnetic Symbol Age ( M i l l i o n s F i e l d of Years) D i r e c t i o n Reversed X -Normal 0 8 Reversed X -Normal 0 • -Normal 0 -Normal 0 8 Reversed X -Reversed X -Normal 0 8 Reversed X -Normal 0 - . Reversed X- -Reversed X -Normal 0 8 Reversed X -Reversed X • -Normal 0 -Reversed X -Normal 0 8 ^ormal 0 -Reversed X -Normal 0 8 Reversed X -Normal 0 8 Reversed X. -Normal 0 Present 4 5 5 S t a t i o n Latitude Longitude Magnetic Symbol Age ( M i l l i o n s F i e l d of Years) D i r e c t i o n 4-8 61.7°N 2 5 . 6 ° W Reversed X . -4 9 61 2 7 . 8 Normal 0 Present (Woodrow 1 9 7 0 ) G. Use your r u l e r to draw a s t r a i g h t l i n e through the stations where the rocks are of the present age. P a r a l l e l to t h i s , draw s t r a i g h t l i n e s through each of the two groups of 8 m i l l i o n year old rocks. Where do you think the Mid-A t l a n t i c Ridge i s located on your map? As you move fa r t h e r away from the ridge, do the rocks become older or younger? Would you expect the rock at Station 5 1 to be older or younger than 8 m i l l i o n years? Would you expect the rock at Sta t i o n 28 to be older or younger than 8 m i l l i o n years? Station 1 5 ? Station 2 5 ? I f the ocean f l o o r i s moving, draw arrows on your map to show i n which d i r e c t i o n s the various parts are moving. H. Use the scale on your map to f i n d the number of k i l o -metres from the Mid-Atlantic Ridge to one of the sets of 8 m i l l i o n year o l d rocks. Write t h i s distance i n your notebook. Change t h i s number of kilometres to centimetres by multiplying by 1 0 0 0 0 0 . Calculate the speed at which the ocean f l o o r near Iceland i s moving by d i v i d i n g your r e s u l t by 8 0 0 0 0 0 0 years. How f a s t i s the ocean f l o o r moving, i n centimetres per year? Remember that the ocean f l o o r i s moving on both sides of the ridge. How f a s t i s the ocean f l o o r spreading i n centimetres per year? I f you l i v e to the age of 9 0 , how much wider w i l l the A t l a n t i c Ocean 4-56 Figure 191. Area of the North A t l a n t i c Ocean where magnetic data was obtained from the sea f l o o r . ( A f t e r Beck, 1977). . 4-57 become i n your l i f e t i m e ? (Beck 1977) Questions . . • 1. I f Europe and North America were once joined, how f a r out from the Mid-Atlantic Ridge would you expect to f i n d the pattern of magnetic revers a l s on the sea f l o o r ? 2. Explain why the magnetic pattern on one side of the Mid-Atlantic Ridge matches the pattern on the other side of the ridge. 5.. E x p l a i n why the pattern of rock ages on one side of the Mid-Atlantic Ridge matches the pattern on the other side of the r i d g e . 4. a) Use your a t l a s to f i n d an approximate distance across the A t l a n t i c Ocean from Europe to Canada. b) Use your r e s u l t s from Procedure H to c a l c u l a t e how long ago Europe and Canada s p l i t apart. Conclusion How does the evidence presented i n t h i s i n v e s t i g a t i o n help support the theory of continental d r i f t ? NARRATIVE 28 Polar Wandering You learned i n Investigation 27 that magnetism preserved i n rocks may be used to f i n d the d i r e c t i o n of the Earth's magnetic f i e l d at 'various times i n the past. This rock magnetism may also be used to f i n d approximately where the north magnetic pole was located m i l l i o n s of years ago. When t h i s i s done, a strange picture emerges. Pigure 192 4-58 Figure 1 9 2 . Former p o s i t i o n s of the Earth's north magnetic pole. The numbers represent m i l l i o n s of years ago. ( A f t e r T a r l i n g _ . . 1 9 7 1 ) • I4-00 Figure 1 9 3 - Moving the continents to match t h e i r polar wandering curves produces a f i t close to the one obtained by the "jigsaw" method. ( A f t e r T a r l i n g 1 9 7 1 ) . 4-59 shows the positions of the magnetic pole, using data from South America and from A f r i c a . The path of the pole's movement appears i n two d i f f e r e n t places! Could the north magnetic pole have been i n two places at the same time? Is i t possible that there might have been two separate north magnetic poles? Both of these suggestions seem to be u n l i k e l y . The theory of continental d r i f t however, can be used to explain these unusual r e s u l t s . I f South America and A f r i c a are placed side by side, as you d i d i n Investigation 26, we f i n d that the polar wandering paths coincide. Figure 1 9 3 shows how t h i s happens. I t appears that f o r a period of nearly 1 5 0 m i l l i o n years, South America and A f r i c a formed a single continent. ijChen t h i s continent broke apart to form the South A t l a n t i c Ocean. The polar wandering curves provide yet another piece of evidence that the theory of continental d r i f t may be c o r r e c t . (Peterson, Rigby 1 9 7 4 ) . INVESTIGATION 30 Earthquakes and C o l l i d i n g Plates Since earthquakes occur wherever rocks are being pushed against and past each other, a great deal of earthquake a c t i v i t y takes place along the edges of p l a t e s . In t h i s exercise you w i l l learn how earthquakes can be used to t e l l us how plates are moving. Purpose: to see how earthquake l o c a t i o n depends on the type of plate boundary. Procedure A. Examine a copy of the World SeismicityMap. Read the 4-60 information i n the "Explanation" box on the map. What magnitude of earthquake do the dots represent? During which years did these earthquakes occur? What magnitude of earth-quake do the c i r c l e s represent? During which years d i d these earthquakes occur? B. On the World Seismicity Map, colours are used to indicate the depth of an earthquake. Copy the table below into your notes, then complete the second column. Depth Colour Shallow ( 0 to 70 km) Intermediate (71 to 300 km) Deep (301 to 700 km) C. Examine Figures 194 to 197 showing four d i f f e r e n t types of plate boundary.. Which diagram best i l l u s t r a t e s plate movement along the Mid-Atlantic Ridge? Which diagram best i l l u s t r a t e s plate movement i n the Himalaya Mountains between India and Asia? D. The table below gives data about the depth and l o c a t i o n of earthquakes along the west coast of South America. Draw, graph axes as shown i n Figure 198 then p l o t the data on your graph. Earthquake number 1 2 3 4 5 6 Earthquake depth (km) 30 60 - 350 260 190 450 Distance (km) and d i r e c t i o n from coast 70 West 330 East 250 E 80 E 230 E 550 E 461 * Earthquakes Figure 194. Plates may s l i d e past each other. * Earthquakes Figure 195. Plates carrying continental crust may c o l l i d e with each other. 462 * Earthquakes Figure 196. A plate with oceanic crust may be pushed beneath a plate with continental crust. * Earthquakes Figure 1 9 7 . Plates with oceanic crust may be pushed apart. 4 6 3 mountains s 100 200 300 400 500 600 xi •p ft-« 700 800 100 0 100 200 300 400 500 600 700 West- - East Distance (km) Figure 198. Grid f o r p l o t t i n g South American earthquake data i n Investigation 29. 4-64-.rthquake number Earthquake depth (km) Distance (km) and d i r e c t i o n from coast 7 1 3 0 40 W 8 20 30 E 9 650 • 420 E 10 280 340 E 11 7 0 1 5 0 E 12 440 260 E 13 5 2 0 625 E 14 9 0 60 W 15 5 0 0 470 E 16 50 30 W 17 2 7 0 160 E 18 80 40 E 19 170 140 E 20 630. 560 E 21 5 2 0 570 E 22 360 400 E 23 3 5 0 ' 1 5 0 E E. Moving inland from the coast, do the earthquakes become deeper or shallower? Which of the plate boundaries shown i n Figures 194 to 197 best seems to show what i s happening . i n South America? Name the plates which are c o l l i d i n g there. V/hich plate i s being subducted beneath (pushed under) the other? Name the range of mountains which has been created by t h i s c o l l i s i o n . F. Examine the World Seismicity Map again. Notice the pattern of coloured dots showing earthquake depths i n South America. 4 - 6 5 Name three other places i n the world which appear to have plate boundaries s i m i l a r to the one i n South America. For each l o c a t i o n you named, give the names of the two plates involved, and say which one i s being subducted beneath the other. (Lowman 1978) Questions 1. Use your a t l a s to f i n d the name of the deep sea trench where subduction i s taking place on the west coast of South America. 2. As the subducted plate i s pushed deeper, i t melts to form magma. What type of mountain i s produced i f some of t h i s magma fi n d s i t s way to the surface of the Earth? 3. Describe the type of plate boundary which best accounts f o r the earthquake a c t i v i t y along .the Queen Charlotte Fau l t , .just o ff the coast of B r i t i s h Columbia. Conclusion What have you learned about earthquakes and plate boundaries i n t h i s investigation? 466 INVESTIGATION ?4 • I d e n t i f i c a t i o n of Minerals Do you r e c a l l your study of plutonic rocks i n Investigation 17? In that exercise you found that plutonic rocks were made up of large c r y s t a l s , a l l interlocked. Each of those c r y s t a l s could be c a l l e d a mineral. A mineral i s a n a t u r a l l y occurring element Or compound. For example, the transparent c r y s t a l s i n granite are a l l c r y s t a l s of the mineral quartz. No matter where they are found, a l l pieces of quartz are made of the same chemical corapond, s i l i c o n dioxide. A l l pieces of quartz have the same chemical formula, SiO£. Another (more valuable) example i s gold. A l l nuggets of the mineral gold are made of the same element with the chemical symbol Au. A prospector must be able to recognize valuable minerals when he f i n d s them. T