UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Geology of Wreck Bay, Vancouver Island Bremner, James Michael 1970

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1970_A6_7 B74_2.pdf [ 21.82MB ]
Metadata
JSON: 831-1.0053108.json
JSON-LD: 831-1.0053108-ld.json
RDF/XML (Pretty): 831-1.0053108-rdf.xml
RDF/JSON: 831-1.0053108-rdf.json
Turtle: 831-1.0053108-turtle.txt
N-Triples: 831-1.0053108-rdf-ntriples.txt
Original Record: 831-1.0053108-source.json
Full Text
831-1.0053108-fulltext.txt
Citation
831-1.0053108.ris

Full Text

THE GEOLOGY OF WRECK BAY, VANCOUVEK ISLAND by JAMES MICHAEL BREMNER B.Sc. ( H o n s . ) , U n i v e r s i t y o f W i t w a t e r s r a n d , J ohanne sbu r g , 1961. A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department o f Geo logy We a c c e p t t h i s t h e s i s as c o n f o r m i n g to the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA J u n e , 1970 In p r e s e n t i n g t h i s t h e s i s in 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 at the U n i v e r s i t y o f B r i t i s h Co lumb i a , I a g ree 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 tudy . 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 pu rpo se s 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 . It i s u n d e r s t o o d tha 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 The U n i v e r s i t y o f B r i t i s h Co lumbia Vancouver 8, Canada Date /<T-~ Ju^t /tfjO ABSfRACT Wreck Bay is located on the west coast of Vancouver Island at 49°00'N, I25°38'W. It is roughly crescent shaped with a small cuspate foreland named Sand Point in the middle, and measures l\ miles (2.17 kilometers) between the enclosing headlands of Q u i s i t i s and Wya Points. Rocks exposed along the coast are indurated, unmeta-morphosed, impure sandstones and mudstones of late Jurassic to early Cretaceous age. They were derived from the hinterland northeast of Wreck Bay, and were rapidly deposited into a trough which extended p a r a l l e l to the present-day coastline. The contact between these sediments and the source rocks is thought to l i e beneath a thick cover of Pleistocene material which now o v e r l i e s the Estevan Coastal Plain; the southwestern edge of the paleotrough, from seismic evidence, appears to l i e 5 - 6 miles (4.35 - 5.22 kilometers) seaward from the present-day coastline. I n f i l l i n g of both sides of this paleo-trough with Pleistocene and Recent sediments has resulted in a narrow, arcuate, present-day trough on the continental shelf adjacent to Wreck Bay. The Pleistocene sediments, consisting of cohesive grey clay and g l a c i o f l u v i a I outwash, were also derived from the mountainous hinterland to the northeast, and Recent sediments derived therefrom are dispersed across the bay and inner shelf. Boulders and gravel freed from the retrograding sea c l i f f behind the beach have settled to the base of wave erosion in the bay, and this coarse "mat" is covered by a thin veneer of very well sorted fine sand which becomes progressively finer further away f r o m s h o r e . A n e a r s h o r e s u r f a c e c u r r e n t t r a n s p o r t s c l a y , s i l t and some o f t h e s a n d s o u t h e a s t w a r d s t o Wya P o i n t and t h e o f f s h o r e t r o u g h . D u r i n g t h e summer, b r e a k e r h e i g h t s i n t h e bay v a r y f r o m 0.75 - 4.00 f e e t (0.23 - 1.27 m e t e r s ) , and i t i s c a l c u -l a t e d t h a t d u r i n g w i n t e r s t o r m s , wave h e i g h t s e x c e e d 19 f e e t ( 5.75 m e t e r s ) . The f o r e s h o r e i n summer c o n s i s t s o f f i n e , l i g h t - c o l o u r e d s a n d , and s l o p e s g e n t l y s e a w a r d a t l e s s t h a n 2.6°. P r o f i l e c h a n g e s o n t h e f o r e s h o r e r e s u l t f r o m t h r e e c o n t r o l l i n g f a c t o r s : t h e b r e a k e r h e i g h t , t h e b r e a k e r i n c i d e n t a n g l e , and t h e p o s i t i o n o f t h e w a t e r t a b l e o n t h e b e a c h . The d i r e c t i o n o f l i t t o r a l d r i f t n e a r t h e m i d d l e o f t h e b e a c h c h a n g e s w i t h t i d e l e v e l , b u t g e n e r a l l y i t i s t o w a r d s Sand P o i n t and v e r y s t r o n g ; n e a r Q u i s i t i s and Wya P o i n t s i t i s weak, and c o n s i s t e n t l y away f r o m them; e l s e w h e r e , i t i s weak and v a r i a b l e i n d i r e c t i o n . T r a n s v e r s e p r o f i l e s w e r e f o u n d t o be most s e n s i t i v e t o t i d a l r a n g e w here t h e b r i s k e r i n c i d e n t a n g l e was s m a l l and c o n s i s t e n t ; t h e y were v i r t u a l l y i n s e n s i t i v e w h e r e t h e b r e a k e r i n c i d e n t a n g l e was s m a l l and v a r i a b l e . I n w i n t e r , t h e f o r e s h o r e i s g e n e r a l l y l e s s s t e e p t h a n i n summer, and n e a r Sand P o i n t t h e s u r f a c e m a t e r i a l o f t h e b e a c h i s r e d u c e d t o c o a r s e g r a v e l as s a n d i s c a r r i e d o u t t o t h e m i d d l e o f t h e b a y ; n o r t h w e s t and s o u t h e a s t f r o m h e r e , t h e b e a c h s u r f a c e c o n s i s t s o f d a r k - c o l o u r e d medium s a n d ; a d j a c e n t t o t h e two h e a d l a n d s , t h e I i g h t - c o I o u r e d f i n e s a n d o f summer r e m a i n s . P r o f i l e c h a n g e s i n w i n t e r a r e d e t e r m i n e d by b r e a k e r h e i g h t s o n l y , t h e o t h e r two c o n t r o l l i n g f a c t o r s b e c o m i n g i n s i g n i f i c a n t . R u n n e l s , o r i n c i p i e n t b e a c h c u s p s , t e n d t o f o r m w h e r e v e r l i t t o r a l d r i f t i s n o t t o o s t r o n g , and t h e i r s p a c i n g i s a p p a r e n t l y r e l a t e d t o t h e t h i c k n e s s o f t h e swash wedge. The c l i f f b a s e a l o n g t h e n o r t h w e s t h a l f o f Wreck Bay v e r y c l o s e l y a p p r o x i m a t e s a l o g - s p i r a l c u r v e i n p l a n due t o t h e a n g u l a r r e l a t i o n s h i p b e t w e e n p r e v a i l i n g wave f r o n t s and t h e c o a s t l i n e ; t h e s o u t h e a s t h a l f , h o w e v e r , does n o t , b e c a u s e a c o m p l e x wave p a t t e r n i s c r e a t e d i n t h e l e e o f i s l a n d s l o c a t e d i n t h e m i d d l e o f t h e b a y . The v a l u e o f g o l d c o n t a i n e d i n t h e b a c k s h o r e n e a r L o s t Shoe C r e e k i s c a l c u l a t e d t o be $10,650. An o f f s h o r e p l a c e r d e p o s i t a t 20 f a t h o m s (3 6 , 6 m e t e r s ) d e p t h i s i n d i c a t e d by a g r e a t i n c r e a s e i n t h e amount o f m a g n e t i t e and o t h e r h e a v y m i n e r a l s t h e r e , t o g e t h e r w i t h t h e f a c t t h a t a s m a l l mode o f v e r y f i n e s a n d , w h i c h c o n t a i n s most o f t h e h e a v y m i n e r a l s o n s h o r e , r e a p p e a r s i n s a m p l e s c o l l e c t e d f r o m t h i s b a t h y m e t r i c l e v e l . F r o n t i s p i e c e - P h o t o m o s a i c o f Wreck Bay. I i n c h = 2250 f e e t . A p p r o x i m a t e s c a l e i TABLE OF CONTENTS I. GENERAL INTKODUCTI ON I A. HISTORICAL BACKGKOUND I B. ACCESS 2 C. TOPOGRAPHY 3 D. CLIMATE 3 E. VEGETATION 4 I I . SEA CONDITlONS A. WAVES 7 B. CURRENTS 8 C. TlDES 9 I I I . PHYSIOGRAPHY OF WRECK BAY AND OFFSHORE TROUGH 13 A. WRECK BAY 13 1. TOPOGRAPHY 13 (a) Methods 13 (b) D i s c u s s i o n \k 2. BATHYMETRY 16 (a) Methods 16 (b) D i s c u s s i o n 16 B. OFFSHORE TROUGH 19 IV. COASTAL ROCKS 23 A. INTRODUCTION 23 B. LOCAL DISTRIBUTION, LITHOLOGY AND STRUCTURE 23 C. EXOTIC MATERIAL 26 D. INTRUSIVES 29 E. RELATIVE AGE 29 1. LOWER LIMIT 29 2. UPPER LIMIT 29 F. REGIONAL DISTRIBUTION AND RELATION TO PRESENT-DAY OFFSHORE TROUGH 31 V. RECENT SEDIMENTS 4 l A. INTRODUCTION 4 l B. POINT-COUNT ANALYSIS 4-2 1. LABORATORY PROCEDURE 42 2. RESULTS 42 3. DISCUSSION 43 (a) M i n e r a l o g i c A s s o c i a t i o n s 43 (b) P rovenance 4-6 C. X-RAY DIFFRACTION ANALYSIS 50 1. LABORATORY PROCEDURE 50 2. X-RAY ANALYSIS 51 3. RESULTS 53 4. DISCUSSION 55 D. GENERAL STRATIGRAPHY OF THE "PARENT" CL IFF MATERIAL 57 V I . SEDIMENT SIZE ANALYSES 65 A. INTRODUCTION 65 B. METHODS 66 1. SAMPLE COLLECTI ON 66 2. LABORATORY PROCEDURE 66 3o STATISTICAL PARAMETERS AND COMPUTER PROGRAM 66 C. REGIONAL SEDIMENTARY PATTERN 67 1. DERIVATION OF TYPE FREQUENCY CURVES 67 2. MODAL ANALYSIS 69 3. TWO-DIMENSIONAL PARAMETER PLOTS 76 (a) Moment Measures vs G r a p h i c a l Methods 76 (b) Env i ronment D i s c r i m i n a t i o n by Two -d imens i ona l P l o t 77 ( i ) Mean vs S t a n d a r d D e v i a t i o n 78 ( i i ) Mean vs Skewness 79 ( i i i ) S t a n d a r d D e v i a t i o n ys Skewness 80 ( i v ) Skewness vs K u r t o s i s 81 4. CONCLUSIONS 81 D. BEACH SEDIMENTARY ENVIRONMENT 86 1. SUMMER 86 2. WINTER 88 3. CONCLUSIONS 90 V I I . TRANSVERSE PROFILES 92 A. INTRODUCTION 92 B. F lELD TECHNIQUES 92 C. STUDY AREAS 93 1. SUMMER CHANGES 9k 2. WINTER CHANGES 96 3. STOKM CHANGES I I I D. DISCUSSION I 15 E. PROFILE CHANGES THROUGH ONE TIDAL CYCLE 120 I . GROSS CHANGES 121 2. NET CHANGES 126 V I I I . SAND MOVEMENT BASED ON WAVE PARAMETERS 130 A. INTRODUCTION 130 B. WAVE PARAMETERS 130 C. LITTORAL ZONE 132 D. CALCULATIONS 132 1. SHALLOW WATER WAVE LENGTH 132 2. TOTAL FORWARD MOVING WAVE ENERGY 133 3. ALONGSHORE ENERGY COMPONENT 133 k. LITTORAL DRIFT \3k E. RESULTS 135 F. DISCUSSION 135 • f • IX. SAND MOVEMENT BASED ON TRACEK DISPERSION 138 A. IMTRODUCTION 138 B. TECHNIQUES 138 1. TRACER PREPARATION 138 2. GRID DIMENSIONS AND SAMPLE RECOVERY 141 3. ENVIRONMENTAL CONDITIONS \k\ k. SURVEY AND PHOTOGRAPHS \k2 5. COUNTING PROCEDURE \k2 C. TREND SURFACE ANALYSIS AND COMPUTER PROGRAMMING 143 D. RESULTS 146 1. PROFILE B ENVIRONMENT 146 2. PROFILE C ENVIRONMENT 151 3. PROFILE D ENVIRONMENT 156 (a) Sand T r a c e r s 156 (b) Grave l T race r s 157 (c) Pebble O r i e n t a t i o n and Movement 162 E. DISCUSSION 166 1. BEACH CUSP FORMATION 166 2. LITTORAL DRIFT 169 X. PLANIMETRIC SHAPE 172 A. INTRODUCTION 172 B. PLAN DATA AQUISITION 173 C. DEFINITION OF A LOGARITHMIC SPIRAL 174 D. TEST PROCEDURE 175 E. COMPUTER TECHNIQUE 176 F. DESCRIPTION OF BEACH SECTIONS STUDIED 177 I, NORTHWEST HALF OF WRECK BAY 177 ?.. SOUTHEAST HALF OF WRECK BAY * 178 G. hESULTS 178 1. NORTHWEST HALF OF WRECK BAY 178 2. SOUTHEAST HALF OF WRECK BAY 179 H. INFERENCES FROM GLACIOFLUVIAL OUTWASH EXPOSED CLIFF SECTIONS 18 I I. THE EFFECT OF WAVES AND CURRENTS IN THE DEVELOPMENT OF HEADLAND-GAY REACHES 183 J . GENERAL KELATIONSHIPS-BETWEEN BAY GEOMETRY AND LOG-SPIRAL PARAMETERS 184 XI. BEACH STRUCTURES 191 A. INTRODUCTION 191 B. MAJOR STRUCTURES 191 1. BERMS 191 2. BARS 191 3. SPITBAR 192 4. SYMMETRICAL CUSPATE FORELANDS 192 C. MINOR STRUCTURES 193 1. BEACH CUSPS 193 2. BEACH RIPPLES 194 i v (a ) Backwash H i p p i e s \9k (b) C u r r e n t R i p p l e s 195 3. KHOMB01D PATTERNS 196 4. K I LL MARKS 198 5. SWASH MARKS 199 6. S/„;0 DOMES 200 7. ORGAN ISM MAKKINGS 200 D, MINOR WAVE TYPES ASSOCIATED WITH BEACH STRUCTURES 205 1. REFLECTED WAVES AND WATER SPOUTS 205 2. HYDRAULIC JUMP WAVES 205 3. SAND WAVES 206 XI I. ECONOMIC BEOLOGY 210 A. REGIONAL ASPECTS 210 B. SUMMARY OF GOLD PRODUCTION AND SAMPLING AT WRECK BAY 211 C. PRESENT INVESTIGATION AND RESULTS 1 212 D. ESTIMATED VALUE OF GOLD NEAR LOST SHOE CREEK 213 E. DISCUSSION AND ECONOMIC S IGN IF ICANCE 214 F. SOURCE OF GOLD AND POSS IBLE OFFSHORE PLACER DEPOSITS 216 X I I I . MARINE L I F E 222 A. INTRODUCTION 222 B. INTRATIDAL ZONE 222 1. SANDY BEACHES 222 2, ROCKY SHORES 223 C. NERIT IC ZONE 225 1. BENTHOS 225 2. NEKTON 225 D. LAND MAMMALS, SEA BIRDS AND SEAWEED 226 XIV. REFERENCES 231 XV. APPENDIX 237 XV I . GLOSSARY 242 V LIST OF TABLES T a b l e I - H i s t o r i c a l w i nd - speed ave rages (%) 4 T a b l e t l - H i s t o r i c a l s to rm ave rage s 8 T a b l e I I I - Wave pa ramete r e s t i m a t e s and o t h e r d a t a from s i x s e t s o f a e r i a l pho tog raphs 10 T a b l e IV - G e n e r a l i z e d s t r a t i g r a p h i c co lumn o f rock s i n the v i c i n i t y o f Wreck Bay 30 Tab l e V - Samples c o n s i d e r e d i n p o i n t - c o u n t and X - r a y d i f f r a c t i o n a n a l y s e s 48 Tab l e VI - P e t r o g r a p h y o f v e r y f i n e sand from f o u r t e e n r e l a t e d env i r onment s 49 T a b l e VII - Coa r se c l a y m i n e r a l o g y and o t h e r p r o p e r t i e s o f t he c l i f f and o f f s h o r e t r ough env i r onment s 60 T a b l e V I I I - Average s t a t i s t i c a l pa ramete r s o f t y p e sed iment from ten r e l a t e d env i r onment s 74 T a b l e IX - Maximum a c c r e t i o n and e r o s i o n v a l u e s a t each p r o f i Ie d u r i ng t he summer 118 T a b l e X - Summary o f wave p a r a m e t e r s . u s e d i n l i t t o r a l d r i f t c a l c u l a t i o n s 131 T a b l e XI - L i t t o r a l d r i f t a t each p r o f i l e d u r i n g t he summer 135 T a b l e XII - T e x t u r a l pa ramete r s o f sand t r a c e r s 140 T a b l e X I I I - P r o p e r t i e s and p e r c e n t a g e r e c o v e r y o f g r a v e l t r a c e r s 140 T a b l e XIV - Hydrodynamic pa ramete r s and a t m o s p h e r i c c o n d i " t i o n s on e x p e r i m e n t a l days 142 T a b l e XV - T i d a l i n f o r m a t i o n and pho tog raph t imes on e x p e r i m e n t a l days 142 T a b l e XVI - Trend s u r f a c e s t a t i s t i c a l d a t a and samp l i n g i n f o r m a t i o n at P r o f i l e s B, C, and D. 146 T a b l e XVII - Pa ramete r s o f be s t f i t t i n g l o q - s p i r a l c u r v e s and o t h e r p e r t i n e n t i n f o r m a t i o n 187 v i T a b l e X V I I I - Summary o f s e m i - q u a n t i t a t i v e i n v e s t i g a t i o n o f g o l d r e c o v e r a b i I i t y by S t e v e n s o n ( 1 9 3 6 ) 211 T a b l e XIX - G o l d and m a g n e t i t e f r o m f i v e e n v i r o n m e n t s a t Wreck Bay 219 T a b l e XX - L i s t o f a n i m a l m a r i n e l i f e c o l l e c t e d o r o b s e r v e d a t Wreck Bay 227 v i i L I S T OF I L L U S T R A T I O N S F I G U R E S AND MAPS F i gu r e 1 - L o c a t i o n map 5 F i g u r e 2 - T y p i c a l w a v e p a t t e r n i n W r e c k B a y 1 1 F i g u r e 3 - E c h o - s o u n d i n g t r a v e r s e s i n W r e c k B a y 20 F i g u r e k - E c h o - s o u n d i n g l i n e s a c r o s s t h e o f f s h o r e t r o u g h 21 F i gu r e 5 - R o c k s a m p l e a n d s o m e r e c e n t s e d i m e n t s a m p l e s i t e s 36 F i g u r e e - W e i g h t p e r c e n t a g e s o f c l a y , s i l t a n d ( s a n d + g r a v e l ) i n c l i f f a n d o f f s h o r e t r o u g h m a t e r i a l 61 F i gu r e 7 - X - r a y d i f f r a c t o q r a m s o f M g - g 1 y c e r a t e d c o a r s e c l a y ( 0 . 2 - 2 . 0 / ~ ) f r o m t h r e e c l i f f a n d t w o o f f -s h o r e t r o u g h s a m p l e s 6 2 F i g u r e 8 - F r e q u e n c y c u r v e s o f t y p e s e d i m e n t f r o m t e n r e l a t e d e n v i r o n m e n t s 75 F i g u r e 9 - B i v a r i a t e p l o t o f m e a n v s . s t a n d a r d d e v i a t i o n ( m o m e n t m e a s u r e s ) 8 2 F i gu r e 10 - B i v a r i a t e p l o t o f m e a n v s . s k e w n e s s ( m o m e n t m e a s u r e s ) 8 3 F i gu r e 1 1 - B i v a r i a t e p l o t o f s t a n d a r d d e v i a t i o n v s . s k e w n e s s ( m o m e n t m e a s u r e s ) 8 4 F i gu r e 12 - B i v a r i a t e p l o t o f s k e w n e s s v s . k u r t o s i s ( m o m e n t m e a s u r e s ) 8 5 F i g u r e 13 - L o n g s h o r e s e d i m e n t p a r a m e t e r s f r o m t h e b e a c h a t W r e c k B a y 91 F i g u r e I'+a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i l e A 9 7 F i g u r e 14b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f P r o f i l e A a t f o u r d i s c r e t e t i m e s 9 7 F i g u r e 15 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e A a s a f u n c t i o n o f t i m e 9 8 F i g u r e 16a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i l e B 9 9 F i g u r e 16b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f P r o f i l e B a t f o u r d i s c r e t e t i m e s 99 • f • V I I I F i g u r e 17 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e f u n c t i o n o f t i m e B a s a 100 F i g u r e 18a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i 1 e C 101 F i g u r e l o b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f f o u r d i s c r e t e t i m e s P r o f i I e C a t 101 F i g u r e 19 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e o f t i m e C a s a f u n c t i o n 102 F i gu r e 2 0 a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i 1 e D 103 F" g u r e 2 0 b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f f o u r d i s c r e t e t i m e s P r o f i I e D a t 103 F" g u r e 2 1 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e o f t i m e D a s a f u n c t i o n 104 F" g u r e 2 2 a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i I e E 105 F" gu r e 2 2 b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f f o u r d i s c r e t e t i m e s P r o f i I e E a t IG5 F g u r e 23 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e o f t i m e E a s a f u n c t i o n ;o6 F gu r e 2 4 a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i 1 e F 107 F ' g u r e 2 4 D - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f f o u r d i s c r e t e t i m e s P r o f i I e F a t 107 F g u r e 25 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i I e o f t i m e F a s a f u n c t i o n 108 F g u r e 2 6 a - H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i 1 e G 109 F g u r e 2 6 b - M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f f o u r d i s c r e t e t i m e s P r o f i I e G a t 109 F g u r e 27 - F o r e s h o r e m o d i f i c a t i o n a t P r o f i I e o f t i me G a s a f u n c t i o n M O F gu r e 2 8 - P r o f i l e c h a n g e s a s a r e s u l t o f s u m m e r ( 1 7 - 19 A u g u s t , 1 9 6 8 ) s t o r m 1 14 F g u r e 23 - C h a n g e s a t P r o f i l e B t h r o u g h o n e t i d a l e y e 1 e 1 23 F g u r e 3 0 - C h a n g e s a t P r o f i l e C t h r o u g h o n e t i d a 1 e y e 1 e 124 F gu r e 31 - C h a n g e s a t P r o f i l e D t h r o u g h o n e t i d a 1 e y e 1 e 125 I X F i g u r e 32 - Net changes at P r o f i l e s B, C, and D a f t e r one t i d a l c y c l e 127 F i g u r e 33 - G e o g r a p h i c a l s e t t i n g a t P r o f i l e B f o r t r a c e r expe r iment 148 F i g u r e ?>h - T r a c e r d i s p e r s i o n r e s u l t s at P r o f i l e B 149 F i g u r e 35 - G e o g r a p h i c a l s e t t i n g a t P r o f i l e C f o r t r a c e r exper iment 153 F i g u r e 36 - T r a c e r d i s p e r s i o n r e s u l t s a t P r o f i l e C 154 F i g u r e 37 - G e o g r a p h i c a l s e t t i n g a t P r o f i l e D f o r t r a c e r exper iment 159 F i g u r e 3'3 - T r a c e r d i s p e r s i o n r e s u l t s a t P r o f i l e D 160 Fi au re 3C; - P e t r o f a b r i c d iag ram o f p e b b l e s h o r t axes ( s ) a t P r o f i Ie D 164 Fi gu re 40 - P l a n i m e t r i c shape o f sp i ra1 c u r v e s Wreck Bay and f i t t e d l o g -88 F i gu re 41a - Reg re s s i on C reek i ne p l o t o f C1i f f b a s e at Lo s t Shoe 189 F i gu re 41b - Reg re s s i on C reek i ne p l o t o f Spi t c r e s t a t L o s t Shoe 189 F i gu re 41c - Reg re s s i on i ne p l o t o f Nor thwes t Co rne r 189 F i gure 42a - Reg re s s i on i ne p l o t o f Sou thea s t Pocket Beach 190 F i gu re 42b - Reg re s s i on i ne p l o t o f Sou thea s t Co rne r (1) 190 F i gu re 42c - Reg res s i on i ne p l o t o f Sou thea s t C o r n e r (2) 190 Map I - Topography and ba thymet r y o f Wreck Bay, Vancouver IsI and Map 2 ~ C o n t i n e n t a l S h e l f Ba thymet ry o f f Wreck Bay, Vancouver Is I and •Pocket Tube Pocket X PLATES P l a t e I - E f f e c t o f s t r o n g o n s h o r e w i n d on c l i f f v e g e t a t i o n 6 P l a t e 2 - S t o r m waves e n t e r i n g Wreck Bay on t h e 18th A u g u s t , 1968 12 P l a t e 3 - Echograms o f some t r a v e r s e s i n Wreck Bay 22 P l a t e 4a - T i g h t l y f o l d e d s a n d s t o n e and m u d s t o n e - F l o r e n c t a I s l a n d 37 P l a t e 4b - M y l o n i t i z e d s a n d s t o n e - F l o r e n c i a ' I s l a n d 37 P l a t e 4c - P h o t o m i c r o g r a p h o f medium g r a i n e d i m p u r e s a n d s t o n e -F l o r e n c i a I s I and 37 P l a t e 5a - C h e r t n o d u l e s and bands i n i m p u r e s a n d s t o n e - Wya P o i n t 38 P l a t e 5b - P i l l o w s t r u c t u r e s i n a l t e r e d b a s a l t - Wya P o i n t 38 P l a t e 6a - L a m i n a t e d c h e r t s h o w i n g s m a l l - s c a l e f o l d i n g - Wya P o i n t 39 P l a t e 6b - P h o t o m i c r o g r a p h o f c h e r t s h o w i n g " c o n c r e t i o n s " -Q u i s l t i s P o i n t 39 P l a t e 7a - M a r b l e b l o c k w i t h b u l b o u s p r o t u b e r a n c e s - Wya P o i n t 40 P l a t e 7b - P h o t o m i c r o g r a p h o f m a r b l e s h o w i n g a l i g n m e n t o f c a l c i t e g r a i n s - Wya P o i n t 40 P l a t e 8a - C o n t a c t b e t w e e n c l a y m a t e r i a l and o v e r l y i n g g l a c i o -f l u v i a l o u t w a s h 63 P l a t e 8b - C l o s e - u p v i e w o f c o n t a c t a r e a m a r k e d by i n s e t on P l a t e 8a 63 P l a t e 9a - P o o r l y d e f i n e d c r o s s b e d d i n g i n g I a c i o f I u v i a I o u t w a s h 64 P l a t e 9b - G I a c i o f l u v i a I o u t w a s h o v e r l a i n p a r t i a l l y by b e a c h ? s a n d , and t i l l 64 P l a t e 10 - P r o c e d u r e u s e d f o r m e a s u r i n g t r a n s v e r s e p r o f i l e s 128 P l a t e I l a - M o u t h o f L o s t Shoe C r e e k on t h e 3 0 t h J u n e 1968 129 x i P l a t e M b - Mouth o f Lo s t Shoe C r e e k on t h e 31 s t J u l y 1968, show ing e x t e n t o f sand a c c r e t i o n 129 P l a t e 12a - P r o f i l e B s h o r t l y a f t e r peak h i g h t i d e , 1500 h o u r s 15'0 P l a t e 12b - P r o f i l e B, 1630 h o u r s 150 P l a t e 12c - P r o f i l e B, 1800 h o u r s 150 P l a t e 13a - P r o f i l e C s h o r t l y a f t e r peak h i g h t i d e , 1430 h o u r s 155 P l a t e 13b - P r o f i l e C , 1600 h o u r s 155 P l a t e 13c - P r o f i l e C, 1730 h o u r s 155 P l a t e 14a - P r o f i l e D s h o r t l y a f t e r peak h i g h t i d e , 1500 h o u r s 161 P l a t e 14b - P r o f i l e D, 1630 h o u r s 161 P l a t e 14c - P r o f i l e D, 1000 h o u r s 161 P l a t e 15 - S w a s h - b a c k w a s h z o n e o v e r g r a v e l f o r e s h o r e a t P r o f i Ie D 165 P l a t e 16 - V i e w n o r t h w e s t f r om Sand P o i n t , s how ing waves b r e a k i n g on t h e n e a r s h o r e b a r 20! P l a t e 17a - R e l i c t c o b b l e cusp a t P r o f i l e C d u r i n g neap t i d e p e r i o d 202 P l a t e 17b - As P l a t e 17a d u r i n g s u c c e e d i n g s p r i n g t i d e p e r i o d 202 P l a t e 17c - As P l a t e 17a d u r i n g s u c c e e d i n g neap t i d e p e r i o d 202 P l a t e 13a - R i l l s e r o d i n g backwash r i p p l e s 203 P l a t e 18b - Sandy b e a c h c u s p s , w i t h backwash r i p p l e s i n t h e embayments 203 P l a t e 18c - C u r r e n t r i p p l e s on t h e lower f o r e s h o r e a t P r o f i l e A 203 P l a t e 19a - Rhomboid p a t t e r n d e v e l o p e d on t h e s e a w a r d s i d e o f backwash r i p p l e s 204 P l a t e 19b - Rhomboid p a t t e r n d e v e l o p e d on g e n t l y s l o p i n g , u n r i p p l e d f o r e s h o r e 204 P l a t e 19c - P s e u d o - r h o m b o i d p a t t e r n d e v e l o p e d i n t h e l e e o f smaI I p e b b I e s 204 P l a t e 20a - S m a l l s p i l l i n g wave a p p r o a c h i n g g r a v e l s t e p n e a r P r o f i Ie D 208 x i i P l a t e 20b - A few s e c o n d s a f t e r P l a t e 20a - r e s u l t a n t swash and r e f l e c t e d wave 208 P l a t e 20c - A few s e c o n d s a f t e r P l a t e 20b - c o l l i s i o n o f r e f l e c t e d wave w i t h t h e n e x t i n c o m i n g s p i l l i n g wave, r e s u l t i n g i n a w a t e r s p o u t 208 P l a t e 21a - H y d r a u l i c jump wave, f rom backwash o v e r - r i d i n g t h e n e x t i n c o m i n g s p i l l i n g wave 209 P l a t e 21b - Sand waves d e v e l o p e d on t h e f o r e s h o r e by a f r e s h w a t e r c r e e k 209 P l a t e 22 - P h o t o m i c r o g r a p h o f l a r g e g o l d " c o l o u r s " 220 P l a t e 23a - " B l a c k s a n d " on t h e f o r e s h o r e d u r i n g w i n t e r . Same v i ew as P l a t e 18b 22 I P l a t e 23b - P r o s p e c t h o l e on t h e b a c k s h o r e n e a r P r o f i l e D 221 P l a t e 24a - A Red Worm and i t s b e a c h m a r k i n g s 229 P l a t e 24b - Raven d i g g i n g s f o r Red Worms 229 P l a t e 25a - K e l p d e p o s i t e d on t h e f o r e s h o r e by o p p o s i n g l i t t o r a l c u r r e n t s 230 P l a t e 25b - C o b b l e s a t t a c h e d t o k e l p h o l d f a s t s 230 x i i i ACKNOWLEDGMENTS Many p e o p l e have c o n t r i b u t e d t o w a r d t h e r e s u l t s o f t h i s work . P r i m a r i l y , I w i s h t o t h a n k D r s , R . E . K u c e r a and J .W. M u r r a y f o r s e r v i n g as t h e s i s a d v i s o r s , and D r , K u c e r a f o r m a k i n g two i n f o r m a t i v e f i e l d t r i p s t o t h e s t u d y a r e a . D r . P. L e B l o n d o f t h e I n s t i t u t e o f O c e a n o g r a p h y , U . B . C , g a v e much h e l p and a d v i s e i n d e t e r m i n i n g t h e p l a n i m e t r i c s h a p e o f Wreck B a y , and D r . L . E . L a v k u l i c h o f t h e D e p a r t m e n t o f S o i l S c i e n c e , U . B . C . , d i r e c t e d my e f f o r t s i n X - r a y d i f f r a c t i o n a n a l y s e s . I am i n d e b t e d t o D r . A . J . S i n c l a i r f o r g u i d a n c e i n t r e n d s u r f a c e a n a l -y s i s o f t h e f o r e s h o r e t r a c e r e x p e r i m e n t s , and t h a n k s a r e due to D r s . W.H.Mathews , W . C . B a r n e s and W . H . W h i t e f o r c r i t i c a l l y r e a d -i n g t h e c h a p t e r s o n T r a n s v e r s e P r o f i l e s , S e d i m e n t S i z e A n a l y s e s , and E c o n o m i c G e o l o g y r e s p e c t i v e l y . F e l l o w U . B . C s t u d e n t s p r o v i d e d many s t i m u l a t i n g i d e a s t h r o u g h d i s c u s s i o n , and were d i r e c t l y r e s p o n s i b l e f o r t h e s u c c e s s o f some p r o j e c t s . S p e c i a l t h a n k s go t o M . J . L . T . P u l l e n , who s u p e r v i s e d t h e echo s o u n d i n g and s a m p l i n g o f Wreck B a y , and L. C a r t e r , who c o l l e c t e d a l l t h e o f f s h o r e s a m p l e s , and r a n t h r e e s o u n d i n g l i n e s a c r o s s t h e o f f s h o r e t r o u g h . F i n a n c i a l a s s i s t a n c e was p r o v i d e d by t h e D e p a r t m e n t o f G e o l o g y and I n s t i t u t e o f O c e a n o g r a p h y , U . B . C , t h r o u g h t h e k i n d e f f o r t s o f D r s . J . W . M u r r a y , R . E . K u c e r a and G . L . P i c k a r d . T h i s s u p p o r t i s g r a t e f u l l y a c k n o w l e d g e d . F i n a l l y , I am d e e p l y t h a n k f u I to my w i f e H e l e n , f o r c h e e r f u l e n c o u r a g e m e n t t h r o u g h o u t t h e r e s e a r c h p e r i o d . I. I. INTRODUCTION A. HISTORICAL BACKGROUND The name Wreck Bay d e r i v e s from an I n c i d e n t which o c c u r r e d i n 1861. In January o f t h a t y e a r , a B r i t i s h v e s s e l H.M. Gunboat Foreward was despatched from E s q u i m a l t to a s s i s t a P e r u v i a n b r i g a n t i n e , the F l o r e n c i a , which had become un-manageable s h o r t l y a f t e r l e a v i n g Juan de Fuca S t r a i t , bound f o r C a l l a o w i t h lumber. The Foreward took F l o r e n c i a i n tow at Nootka, and w h i l e heading f o r V i c t o r i a e x p e r i e n c e d b o i l e r t r o u b l e h e r s e l f , and was f o r c e d to c u t her charge a d r i f t . The F l o r e n c i a went aground on a s m a l l i s l a n d now known as F l o r e n c i a I s l a n d , where she became a t o t a l wreck ( N i c h o l s o n , 1965). S i n c e 1930, a number o f maps and r e p o r t s have r e f e r r e d to the bay leeward o f the i s l a n d as F l o r e n c i a Bay; i n t h i s t h e s i s the o r i g i n a l name, Wreck Bay, has been used. Long Beach was f i r s t known as W i c k a n i n n i s h Beach a f t e r the c h i e f o f the C l a y o q u o t i n d i a n s , who o v e r a hundred y e a r s ago r e i g n e d supreme o v e r t h i s p a r t o f the c o a s t ( N i c h o l -son, 1965). Most maps s t i l l mark the n e a r s h o r e r e g i o n as Wickani nni sh Bay, The rocky p r o m o n t o r i e s on e i t h e r s i d e o f Wreck Bay, Qui s i t i s Poi nt and Wya P o i n t , were a p p a r e n t l y named a f t e r o l d i n d i a n v i l l a g e s once l o c a t e d t h e r e ( p e r s o n a l communication w i t h l o c a l i n d i a n s ) . The f i r s t w h i t e men to s e t t l e t h i s c o a s t e s t a b l i s h e d f u r - t r a d i n g p o s t s at C l a y o q u a t ( a c r o s s the bay from T o f i n o ) and 2. a t U c l u e l e t i n t h e l 8 7 0 ' s . S h o r t l y b e f o r e t h e F i r s t W o r l d War a b o u t t w e n t y B r i t i s h i m m i g r a n t s a t t e m p t e d f a r m i n g i n t h e T o f i n o a r e a , and by IS20 t h e a r e a had b e e n f a i r l y t h o r o u g h l y combed f o r i t s m i n e r a l d e p o s i t s by m i g r a n t p r o s p e c t o r s . G o l d was d i s c o v e r e d i n a number o f q u a r t z v e i n s a l o n g t h e E l k R i v e r (nOw known as t h e Kennedy R i v e r ) , and i n t h e " b l a c k s a n d s " o f Wreck B a y . D u r i n g t h e S e c o n d W o r l d War, t h e a r e a u n d e r w e n t e x t e n s i v e d e v e l o p m e n t as p a r t o f t h e U n i t e d S t a t e s d e f e n s e m e a s u r e s a g a i n s t p o s s i b l e J a p a n e s e a t t a c k . An a i r f i e l d was b u i l t n e a r Long B e a c h , and a r o a d was c o n s t r u c t e d b e t w e e n T o f i n o and U c l u e l e t . T o d a y , t h e p r i n c i p a l i n d u s t r y o f t h e s e two v i l l a g e m u n i c i p a l i t i e s i s f i s h i n g , and have p o p u l a t i o n s o f a p p r o x i m a t e l y 500 and 700 r e s p e c t i v e l y . B. ACCESS R e g u l a r f e r r y s e r v i c e s e x i s t b e t w e e n V a n c o u v e r and V i c t o r i a , and b e t w e e n H o r s e s h o e Bay and Nana imo. A p a v e d h i g h -way l i n k s t h e s e two c i t i e s w i t h P o r t A l b e r n i , and f r o m h e r e , a rough g r a v e l r o a d w i n d s o v e r t h e I n s u l a r M o u n t a i n s t o t h e west c o a s t o f V a n c o u v e r I s l a n d ( F i g u r e I ) . F o r a number o f y e a r s t h i s g r a v e l s e c t i o n has b e e n u n d e r c o n s t r u c t i o n , and i s s l a t e d t o be c o m p l e t e l y p a v e d by m i d - 1 9 7 0 . It end s a t a j u n c -t i o n , 20 m i l e s f r om T o f i n o , and 6 m i l e s f r o m U c l u e l e t . The W i c k a n i n n i s h r o a d l e a d s t o Wreck Bay f r o m a t u r n o f f 3 m i l e s n o r t h o f t h i s j u n c t i o n (Map 2 ) . A l t e r n a t i v e l y t h e a r e a may be r e a c h e d by b o a t , as g o v e r n m e n t d o c k i n g f a c i l i t i e s e x i s t a t b o t h T o f i n o and 3. U c l u e l e t . A i r s e r v i c e i s p r o v i d e d by CP A i r , w i t h t h r e e r e t u r n f l i g h t s a week f r o m V a n c o u v e r . C. TOPOGRAPHY. Be tween t h e P a c i f i c Ocean and t h e w e s t e r n b o u n d a r y o f t h e I n s u l a r M o u n t a i n s , a n a r r o w l o w l a n d s t r i p known as t h e E s t e v a n C o a s t a l P l a i n e x t e n d s a l o n g t h e g r e a t e r p a r t o f V a n c o u v e r I s l a n d ' s west c o a s t ( H o l l a n d , 1964 ) . The a r e a l y i n g b e t w e e n Wreck Bay and t h e s o u t h s i d e o f Kennedy L a k e i s a p p r o x i m a t e l y 4 m i l e s w i d e , and c o n s i s t s o f u n c o n s o l i d a t e d g r a v e l s and s and s b e l o w 200 f e e t e l e v a t i o n . N o r t h w e s t and s o u t h e a s t f r o m h e r e , a number o f i s o l a t e d h i l l s o f ba sement p r o j e c t up t h r o u g h t h e u n c o n s o l i d a t e d s e d i m e n t t o e l e v a t i o n s r e a c h i n g 700 f e e t a b o v e s e a l e v e l . The a r e a i s c h a r a c t e r i z e d by low t o p o g r a p h i c r e l i e f , b u t l o c a l l y , a few g e n t l e r i d g e s and s h a l l o w d e p r e s s i o n s b r e a k t h e g e n e r a l u n i -f o r m i t y . Some o f t h e s e d e p r e s s i o n s p r o b a b l y r e f l e c t t h e c o u r s e o f o l d s t r e a m c h a n n e l s ( s e e c h a p t e r on ECONOMIC GEOLOGY). D. CL IMATE The a r e a has a h i g h a n n u a l p r e c i p i t a t i o n , most o f w h i c h o c c u r s d u r i n g t h e w i n t e r a s r a i n . F o r 1963, U c l u e l e t r e c o r d e d t h e h i g h e s t r a i n f a l l a c r o s s Canada - 265 .23 i n c h e s , and t h a t w i n t e r , T o f i n o e x p e r i e n c e d o n e o f t h e h e a v i e s t snow-f a l l s i n l i v i n g memory - more t h a n 2 f e e t . In summer t h e d a y s a r e l ong and warm. E a r l y m o r n i n g f o g o f t e n b l a n k e t s t h e c o a s t a l p l a i n , and w i n d s a r e g e n e r a l l y 4. l i g h t f r o m t h e n o r t h w e s t . From l a t e autumn t o w i n t e r , s t o r m f r e q u e n c y and i n t e n s i t y i n c r e a s e s , and t h e w i n d s h i f t s g r a d u -a l l y t o t h e s o u t h . A summary o f h i s t o r i c a l w i n d - s p e e d a v e r a g e s i s g i v e n i n T a b l e I (Wa t t s and F a u l k n e r , 1963 ) . S E A S O N \ M . p . H . 0 - 10 10 - 20 j 20 - 30 j 30 - 40 >40 A p r i 1 - S e p t e m b e r O c t o b e r - M a r c h 4 2 . 0 20 . 7 4 1 . 5 4 0 . 3 12.3 | 2.9 2 6 . 4 j 3 .4 0 . 8 4 . 2 TABLE I - H ISTORICAL WIND-SPEED AVERAGES (%) E.. VEGETATION S e c t i o n s o f t h e c l i f f b e h i n d Wreck Bay c a r r y l a r g e s t r a i g h t t r e e s o f f i r , c e d a r , h e m l o c k and d e n s e a l d e r . F u r t h e r n o r t h a t P a r a d i s e B e a c h and p a r t s o f Long B e a c h , t h e c l i f f i s l e s s t h a n 10 f e e t h i g h , and h e r e , t h e t r e e s a r e s c r u b b y and bend s t r o n g l y i n l a n d ( P l a t e I ) . T h i s d i f f e r e n c e i s due t o t h e w ind b e i n g d e f l e c t e d upwards a t Wreck B a y , t h u s c a u s i n g n e g l i -g i b l e d i s t o r t i o n i n t h e t r e e s g r o w t h ; e l s e w h e r e t h e w i n d d r i v e s s t r a i g h t i n l a n d . A n o t h e r r e s u l t o f low c l i f f h e i g h t s i s e x e m p l i f i e d a l o n g t h e s o u t h e a s t e r n p a r t o f Long B e a c h . H e r e t h e c l i f f i s v i r t u a l l y a b s e n t , and sand f r om t h e b a c k s h o r e has d r i f t e d l a n d w a r d c o v e r i n g t h e v e g e t a t i o n o v e r a 2 to- 3 a c r e a r e a . L o g g i n g i n l a n d f r om Wreck Bay has i n p l a c e s p r o -g r e s s e d t o w i t h i n 1 m i l e f r om t h e c l i f f . The n o r t h e r n s e c t o r c l o s e t o t h e r o a d has no t b e e n l o g g e d b e c a u s e t h e g r o u n d i s swampy, and t r e e s a r e s m a l l and s c r u b b y . P l a t e I. E f f e c t o f s t r o n g o n s h o r e w i n d s d u r i n g t h e w i n t e r , on v e g e t a t i o n l o c a t e d a b o v e a low p r o f i l e c l i f f . P a r a d i s e B e a c h , 2 m i l e s s o u t h e a s t f r om T o f i n o . 7, U n d e r b r u s h i s commonly b l u e b e r r i e s , s a I m o n b e r r i e s , s a l a l and h u c k l e b e r r i e s , w h i c h o c c a s i o n a l l y f o r m i m p e n e t r a b l y t h i c k g r o w t h s . II, SEA COND!TlONS A. WAVES A p e r s i s t e n t g r o u n d s w e l l a p p r o a c h e s t h e west c o a s t o f V a n c o u v e r I s l a n d f rom t h e w e s t , b u t d u r i n g t h e w i n t e r months w i n d - b l o w n s t o r m waves f r om t h e s o u t h o c c a s i o n a l l y become d o m i n a n t . D u r i n g t h e summer o f 1968, wave p a r a m e t e r s m e a s u r e d on t h e b e a c h a t Wreck Bay w e r e : s i g n i f i c a n t b r e a k e r h e i g h t s and p e r i o d = 0 . 7 5 - 4 . 0 0 f e e t and 10 s e c o n d s r e s p e c t i v e l y ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). The p a t t e r n o f wave d i f f r a c t i o n a r o u n d t h e h e a d l a n d s and i s l a n d s i n t h e b a y , and r e f r a c t i o n on t h e s h o a l i n g b o t t o m , i s shown i n F i g u r e 2 and on t h e F r o n t i s p i e c e . The i n c i d e n t a n g l e o f b r e a k e r s a t t h e v a r i o u s p r o f i l e l o c a t i o n s were e s t i m a t e d f r o m a e r i a l p h o t o g r a p h s . T h i s i n f o r m a t i o n , t o g e t h e r w i t h o t h e r e s t i m a t e d h y d r o d y n a m i c and a t m o s p h e r i c d a t a i s g i v e n i n T a b l e I I I . A s i n g l e s t o r m a t t a c k e d t h e c o a s t d u r i n g t h e summer, and b r e a k e r h e i g h t s and p e r i o d s i n c r e a s e d t o I 6 i f e e t and 12 s e c o n d s r e s p e c t i v e l y ( P l a t e 2 ) . Wave m e a s u r e m e n t s made a b o a r d S h e l l C a n a d a ' s o i l -d r i I I r i g SEDCO 135 -F d u r i n g t h e w i n t e r o f 1967 - 6 8 , i n d i c a t e t h a t s w e l l h e i g h t s r a n g e d f r om 6 - 1 0 f e e t , and s w e l l p e r i o d s r a n g e d f r o m 9 - II s e c o n d s ( W a t t s and F a u l k n e r , 1968) . The 8. w o r s t s t o r m e x p e r i e n c e d by t h e d r i l l r i g o c c u r r e d i n December 1967- Winds r e a c h e d 76 mph, w i t h g u s t s t o 92 mph f rom t h e s o u t h e a s t , and maximum wave h e i g h t s r e c o r d e d were 35 f e e t . The h i g h e s t s t o r m waves e n c o u n t e r e d d u r i n g t h e w i n t e r were r e -c o r d e d i n J a n u a r y 1968. Comb ined s w e l l and wave h e i g h t a t t h i s t i m e r e a c h e d 58 f e e t , a f t e r s e v e r a l days o f 40-50mph w i n d s . H i s t o r i c a l a v e r a g e s o f s t o r m s a l o n g t h e west c o a s t o f V a n c o u v e r I s l a n d a r e shown i n T a b l e II ( W a t t s and F a u l k n e r , 1963 ) . Maximum s t o r m S u s t a i n e d 1 h o u r w i n d s p e e d (mph) Maximum wave h e i g h t ( f t ) Wave p e r i o d ( s e e s ) A n n u a l summer s t o r m ( M a y - A u g u s t ) 40 30 15 A n n u a l s t o r m 70 45 •5 1 0 0 - y e a r s t o r m 100 70 15 | TABLE I I - H i s t o r i c a l A v e r a g e s o f S t o rms B. CURRENTS An a t t e m p t was made on t h e 8 t h J u l y 1963 t o m e a s u r e n e a r - b o t t o m c u r r e n t v e l o c i t i e s and d i r e c t i o n s i n Wreck B a y , w i t h a S a v o n i u s C u r r e n t M e t e r . Due t o m e c h a n i c a l p r o b l e m s , o n l y o n e s u c c e s s f u l measurement was o b t a i n e d . T h i s was l o c a -t e d i n 40 f e e t o f w a t e r i n t h e deep i m m e d i a t e l y n o r t h w e s t o f F l o r e n c i a I s l a n d (Map I ) . A s e a w a r d mov ing c u r r e n t w i t h v e l o -o c i t y o f 0 .2 k n o t s , and a z i m u t h 215 , was m o n i t o r e d I h o u r a f t e r t h e t i d e had t u r n e d t o e b b . S u r f a c e c u r r e n t m e a s u r e m e n t s were made on t h e same day u s i n g f l o a t b o t t l e s , w h i c h had been w e i g h t e d t o s i n k j u s t b e n e a t h t h e s e a - a i r i n t e r f a c e . F i v e b o t t l e s were d r o p p e d a l o n g a l i n e b e t w e e n Wya P o i n t and F l o r e n c i a I s l a n d , o f w h i c h two were r e c o v e r e d f i v e h o u r s l a t e r a p p r o x i m a t e l y o n e m i l e s o u t h e a s t o f t h e i r d r o p - p o i n t s . A n o t h e r f i v e b o t t l e s were d r o p p e d a l o n g a l i n e b e t w e e n F l o r e n c i a I s l a n d and O u i s i t i s P o i n t , None o f t h e s e were r e c o v e r e d , b u t o n e was s i g h t e d i n t h e m i d d l e o f t h e bay by a l o c a l f i s h e r m a n a p p r o x i m a t e l y t h r e e h o u r s l a t e r . T h e s e t r e n d s i n d i c a t e a s l o w s o u t h e a s t m o v i n g s u r f a c e c u r r e n t i n t h e n e a r s h o r e z o n e . W a t t s and F a u l k n e r (1968) r e p o r t maximum c u r r e n t s on t h e s h e l f d u r i n g s t o r m s , o f 2.5 k n o t s . They do no t s p e c i f y t h e c u r r e n t d i r e c t i o n , bu t p r e s u m a b l y i t i s s o u t h e a s t w a r d s , c o n f o r m a b l e w i t h t h e n e a r s h o r e s u r f a c e c u r r e n t . C. T IDES The west c o a s t o f V a n c o u v e r I s l a n d i s a f f e c t e d by m i x e d s e m i - d i u r n a l t i d e s w i t h a mean r ange o f 3 .7 f e e t d u r i n g neap t i d e s , and 12.9 f e e t d u r i n g s p r i n g t i d e s ( C a n a d i a n T i d e and C u r r e n t T a b l e s , 1968) . The n e a r e s t r e f e r e n c e p o r t on w h i c h a l l t i d e e l e v a t i o n s i n t h i s t h e s i s were b a s e d , i s T o f i n o , l o c a t e d a p p r o x i m a t e l y 20 m i l e s n o r t h w e s t f r om Wreck Bay . 10. A lRPH0T0 DATA D a t e 17 J u n e 1967 1 May 1966 15 O c t . J29 S e p t . 1954 |1950 i 29 Sept.fc 1930 ( A - 3 0 3 2 ) 19 S e p t . 930 (A -5874 ) A v e r ^ age A p p r o x , Sea 1 e 1"=2640' 1 " = 1 3 2 0 ' 1"=2640' 1"=980' E 1 e v a t i o n ( f t a . s . 1 . ) 17,000 8 . 2 0 0 2 0 , 0 0 0 5 ,500 10,700 g r e a t e r t h a n 11,000 A z i m u t h o f deep w a t e r wave f r o n t s 1 8 5 ° 1 7 0 ° o 190 o 200 o 175 , o 160 ,, o 180 E s t i m a t e d t i d e h e i g h t M i d M i d H i g h M i d Low Low A z i m u t h o f F l o r e n c i a ^ . foam 1i ne ' o 75 3 6 0 ° 2 0 ° 1 3 5 ° o 320 o 350 E s t i m a t e d wi nd s t r e n g t h Mod. L i g h t V e r y s t rong L i g h t Ca Im Mod. 1 NCI DENT ANGLE OF * * * BREAKERS TO BEACH ( d e g r e e s ) A -5 - 7 - -5 -1 1 - 7 B - 4 -3 -6 - - 2 3 - 2 C 3 - 2 -3 - -1 3 1 D -6 -8 0 - -5 5 - 4 E 5 - 7 -13 - 2 1 1 3 F - 1 0 -1 -2 -3 2 - 1 G 5 i_ 7 2 5 7 6 6 Tab Ie I I I . - Wave P a r a m e t e r E s t i m a t e s , and o t h e r D a t a , f r o m s i x S e t s o f A e r i a l P h o t o g r a p h s . * A v e r a g e o f i n c i d e n t a n g l e o f b r e a k e r s e x c l u d i n g s t o r m v a l u e s on 15 O c t . 1954. * * I n d i c a t e s w i n d d i r e c t i o n as m e a s u r e d f r o m t h e m e r i d i a n on an i m a g i n a r y h o r i z o n t a l c i r c l e w i t h F l o r e n c i a I s l a n d as c e n t e r . * * * - S i g n i n d i c a t e s a s o u t h e a s t d i r e c t i o n , no s i g n i n d i c a t e s a n o r t h w e s t d i r e c t i o n . T y p i c a l wave p a t t e r n i n Wreck Bay. Drawn f rom a e r i a l p h o t o g r a p h s shown on F r o n t i s p i e c e . P l a t e 2. S t o r m waves e n t e r i n g Wreck Bay on 18th Aug . 1968. The p h o t o g r a p h was t a k e n f rom t h e b e a c h a t P r o f i l e C. F i v e rows o f b r e a k e r s c a n be s e e n t r a v e r s i n g t h e s u r f z o n e . 13. M l . PHYSIOGRAPHY OF WRECK BAY AND OFFSHORE TROUGH A. WRECK BAY I. TOPOGRAPHY (a ) M e t h o d s N i n e day s be tween t h e 5 t h and 2 0 t h A u g u s t 1968 were s p e n t p l a n e t a b l i n g t h e t h r e e m i l e l e n g t h o f b e a c h b e t w e e n Q u i s i t i s P o i n t and Wya P o i n t (Map I ) . The p u r p o s e o f t h i s u n d e r t a k i n g was t o o b t a i n an a c c u r a t e l a r g e - s c a l e map o f t h e p r i n c i p a l s t u d y a r e a o f t h i s t h e s i s . A t e l e s c o p i c a l i d a d e and e n g i n e e r s s t a d i a r o d was u s e d , and a l o c a l r e s i d e n t was tempo-r a r i l y e m p l o y e d as an a s s i s t a n t . A s c a l e o f I i n c h = 200 f e e t p e r m i t t e d mapp ing o f m a j o r b e a c h s t r u c t u r e s i n c l u d i n g o e r m s , r e l i c t c o b b l e c u s p s , e t c ( s e e c h a p t e r on BEACH STRUCTURES ) , and 13 r od s t a t i o n s a t t h e c l i f f b a s e p r o v i d e d t h e n a c e s s a r y d a t a f o r e x a m i n i n g s h o r e l i n e s t a b i l i t y a t Wreck Bay ( s e e c h a p t e r on PLANIMETRIC SHAPE) . No c o n v e n i e n t b e n c h marks e x i s t i n t h e a r e a , so e l e -v a t i o n s were b a s e d on t i d e h e i g h t s a t s p e c i f i c t i m e s , i n a r e a s where t h e sea s u r f a c e was c a l m . On t h e 5 t h A u g u s t , a l ower h i g h t i d e o f 9.1 f e e t a b o v e datum o c c u r r e d a t 11 .40 a . m . , and a r ock o u t c r o p on Q u i s i t i s P o i n t was marked w i t h p a i n t a t t h i s s e a - l e v e l . S i m i l a r l y a t Wya P o i n t , a r o c k o u t c r o p was marked a t s e a - l e v e l on t h e 18th A u g u s t , when a l ower h i g h t i d e 8.C f e e t a b o v e datum o c c u r r e d a t 10.10 a.m. C h a r t datum a d o p t e d by t h e C a n a d i a n H y d r o c r a p h i c S e r v i c e i s b a s e d on t h e p l a n e o f I k. l owes t norma l t i d e s ( C a n a d i a n T i d e and C u r r e n t T a b l e s , I 9 o o ) . V e r t i c a l c o n t r o l was m a i n t a i n e d by f i r s t s u r v e y i n g t h e n o r t h w e s t h a l f o f t h e b e a c h f r om t h e Q u i s i t i s P o i n t r e f e r e n c e e l e v a t i o n , t o a l a r g e s t a t i o n a r y t r e e - s t u m p on Sand P o i n t . The s o u t h e a s t h a l f was t h e n s u r v e y e d f r o m t h e Wya P o i n t r e f e r e n c e s t a t i o n t o t h e same t r e e - s t u m p . A v e r t i c a l e r r o r o f 0 . 3 8 f e e t f o r t h e t r e e - s t u m p e l e v a t i o n was o b t a i n e d f r om t h e two d i f f e r e n t a p p r o a c h e s , w h i c h was e l i m i n a t e d by a d j u s t i n g two i n s t r u m e n t s t a t i o n e l e v a t i o n s on e i t h e r s i d e o f t h e t r e e - s t u m p . H o r i z o n t a l c o n t r o l was m a i n t a i n e d by s h o o t i n g a ray a t a r o c k p i n n a c l e on S e a l Rock f r om e a c h i n s t r u m e n t s t a t i o n . D u r i n g map c o m p i l a t i o n , i n s t r u m e n t s t a t i o n s were a d j u s t e d so t h a t t h e i r r a y s a l l c o i n c i d e d i n a s i n g l e p o i n t . A number o i p o i n t s on t h e c I i f f edge, were f i x e d by t r i a n g u I a t i o n f r om t h e i n s t r u m e n t s t a t i o n s , and t h e i r e l e v a -t i o n s were d e t e r m i n e d f r o m t h e i n c l i n a t i o n a n g l e s . The two h e a d l a n d s e n c l o s i n g Wreck B a y , Q u i s i t i s P o i n t and Wya P o i n t , were drawn o n t o Map I by e x p a n d i n g t h e s c a l e o f a e r i a l p h o t o -g r a p h s t o t h a t o f t h e s u r v e y u s i n g a S a l t z m a n Map P r o j e c t o r . The g e n e r a l o u t l i n e s o f F l o r e n c i a I s l a n d and S e a l Rock were p l o t t e d i n t h e same way. M a j o r f a u l t s shown on Map I were mea-s u r e d a t t h e f i e l d l o c a t i o n s , and s u p p l e m e n t e d by a i r - p h o t o i n t e r p r e t a t i o n . (b) Di s c u s s i on The b a c k s h o r e i s e x c e p t i o n a l l y w i d e a d j a c e n t t o t h e 15. two h e a d l a n d s , b e t w e e n P r o f i l e s A . a n d B and P r o f i l e s F and G (Map I ) . T h e s e r e g i o n s r e p r e s e n t t h e more s t a b l e c l f f f s e c t i o n s b e h i n d t h e bay ( s e e c h a p t e r on PLANIMETRIC SHAPE ) . The f o r e -s h o r e i s e x c e p t i o n a l l y w i d e and f l a t a t Sand P o i n t , and s t e e p and n a r r o w a t i t s f l a n k s . T h i s c o n f i g u r a t i o n i s e s t a b -l i s h e d by l i t t o r a l c u r r e n t s , w h i c h a r e a f u n c t i o n o f t i d e h e i g h t ( s e e c h a p t e r on SAND MOVEMENT BASED ON TRACER DISPER-S ION) , and wave h e i g h t ( s e e c h a p t e r s on SEDIMENT S I ZE ANALYSES and TRANSVERSE P R O F I L E S ) . R e l i c t g r a v e l b e a c h c u s p s e x i s t f r o m t h e mouth o f L o s t Shoe C r e e k , a l o n g t h e s p i t b a r , t o t h e a r e a b e t w e e n P r o f i l e s C and D. A l a r g e number o f f r e s h w a t e r s p r i n g s emerge f r o m t h e c l i f f b a s e b e t w e e n P r o f i l e s F and G, and 800 f e e t s o u t h e a s t o f P r o f i l e E. T h e s e s p r i n g s r e s u l t e d i n s t r o n g e r o s i o n o f t h e summer b e r m , l e a v i n g i t as a s e r i e s o f d i s c r e t e s andy mounds ( s e e Map I and c h a p t e r on BEACH STRUCTURES) . The s p i t b a r , w h i c h d e f l e c t s t h e o u t l e t o f L o s t Shoe C r e e k f o r 1250 f e e t n o r t h w e s t w a r d s , r e a c h e s a maximum h e i g h t o f 23 f e e t a b o v e s e a l e v e l a l o n g i t s c r e s t . I t f i t t e d t h e o r e t i c a l l o g - s p i r a l c u r v a t u r e much more c l o s e l y t h a n d i d t h e c l i f f b a s e i n t h i s a r e a ( s e e c h a p t e r on PLANIMETRIC SHAPE ) . Sea c a v e s and b l o w h o l e s a r e q u i t e common a l o n g t h e s o u t h e r n p a r t o f Q u i s i t i s P o i n t . S t r o n g wave a c t i o n has p r e f -e r e n t i a l l y e r o d e d t h e r o c k y c o a s t s a l o n g f a u l t p l a n e s , t h u s mak ing t h e i r r e c o g n i t i o n f a i r l y e a s y . 16. 2. BATHYMETRY (a ) M e t h o d s The bay was e c h o - s o u n d e d on t h e 5 t h and 6 t h J u l y 1968, t h e p u r p o s e o f w h i c h was t o o b t a i n an a c c u r a t e b a t h y -m e t r i c map, and t o d e l i n e a t e e x p o s e d b o u l d e r and b e d r o c k a r e a s i n t h e b a y . A F u r u n o Mode l F -850 Mark II e c h o - s o u n d e r was u s e d on 16 f o o t m o t e r l a u n c h . I t had an o p e r a t i n g f r e q u e n c y o f 28 .5 K c / s , and a p u l s e l e n g t h o f 1.3 ms. I n i t i a l t r a v e r s e s were e x t e n d e d f r o m t h e b e a c h p r o f i l e l i n e s o u t i n t o t h e bay (PL l i n e s ) , and s u b s e q u e n t l y , a r e c t a n g u l a r g r i d was f o l l o w e d t o o b t a i n d e t a i l i n u n c o v e r e d a r e a s (GL l i n e s ) - s ee F i g u r e 3. At e a c h o f t h e t i m e s t a t i o n s shown, a s e x t a n t was u s e d t o m e a s u r e s i m u l t a n e o u s t a n g e n t i a l a n g l e s be tween t h r e e p r o m i n e n t t o p o g r a p h i c f e a t u r e s on t h e s h o r e . C u r v e s on t i d a l e l e v a t i o n f o r t h e p e r i o d s s p e n t i n t h e f i e l d , were p l o t t e d on g r a p h p a p e r and t h e n a p p r o p r i a t e a d j u s t m e n t s made on t h e e c h o g r a m m e a s u r e m e n t s . P r o n o u n c e d 2nd and o c c a s i o n a l l y 3 r d m u l t i p l e r e f l e c t i o n s were i n t e r p r e t e d as b e d -r o c k i f t h e y showed p o s i t i v e r e l i e f , and as b o u l d e r beds i f z e r o o r n e g a t i v e r e l i e f was i n d i c a t e d ( P l a t e 3 ) . K e l p bed s p r o d u c e d s t r o n g r e f l e c t i o n s a b o v e t h e r o c k - w a t e r i n t e r f a c e . (b ) D? s c u s s i o n K i n g (1967) f o u n d t h a t a r e l a t i v e l y h i g h f r e q u e n c y , s h o r t p u l s e - l e n g t h e c h o - s o u n d e r s u c h as t h i s , e n a b l e d h im t o d e l i n e a t e f o u r d i s t i n c t s e d i m e n t a r y t y p e s on t h e S c o t i a n S h e l f . 17. In t h e p r e s e n t s t u d y , e c h o r e f l e c t i o n i n t e n s i t y i n d i c a t e d a s i n g l e s e d i m e n t t y p e i n t h e b a y , and f r o m s a m p l i n g t h i s t u r n e d o u t t o be f i n e s a n d . B o u l d e r a r e a s shown on Map I c a n n o t r e p r e s e n t z o n e s o f b o u l d e r c o n c e n t r a t i o n , s i n c e a number o f them a p p e a r t o e x c e e d I t o n i n w e i g h t . R a t h e r , t h e y r e p r e s e n t a r e a s where s and has b e e n s e l e c t i v e l y w innowed o u t , l e a v i n g t h e b o u l d e r s as l a g d e p o s i t s . I t i s b e l i e v e d t h a t a " m a t " o f b o u l d e r s , d e r i v e d f r o m t h e g l a c i o f l u v i a l o u t w a s h , u n d e r l i e s t h e e n t i r e b a y . The l a r g e b o u l d e r a r e a i n t h e n o r t h w e s t c o r n e r o f t h e bay i s a r e s u l t o f two f a c t o r s : g r e y c o h e s i v e c l a y b e n e a t h t h e s and e f f e c t i v e l y p r o h i b i t s b o u l d e r s f r o m s i n k i n g ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) , and a p e r s i s t e n t r i p -c u r r e n t i n t h i s r e g i o n a l l o w s o n l y a t h i n c o v e r o f s and t o b l a n k e t t h e g r e y c l a y ( s e e F r o n t i s p i e c e , and c h a p t e r on PLANIMETRIC SHAPE ) . The e l o n g a t e b o u l d e r bed e x t e n d i n g f r o m S e a l Rock t o w a r d t h e mouth o f L o s t Shoe C r e e k , o c c u p i e s a d i s t i n c t t r o u g h and s u p p o r t s no k e l p ( P l a t e 3 - l i n e s GL2 and P L © ) I t p r o b a b l y r e p r e s e n t s an i n t e r - l o n g s h o r e - b a r t r o u g h , as does t h e s m a l l b o u l d e r a r e a c l o s e r t o s h o r e c o n t a i n i n g s a m p l e B 3 , s i n c e a s h o a l a r e a e x i s t s b e t w e e n them, and s e a w a r d o f t h e l a r g e r b o u l d e r b e d . M o t h e r s i I I (1969) f o u n d t h a t as a r e s u l t o f wave a c t i o n , l o n g s h o r e b a r s i n L a k e S u p e r i o r c o n s i s t e d o f 18. f i n e s a n d , w h e r e a s t h e i n t e r v e n i n g t r o u g h s c o n t a i n e d e x c e s s c o a r s e m a t e r i a l . Due t o t h e d e p t h o f t h e s e f e a t u r e s , t h e y most l i k e l y d e v e l o p e d i n r e s p o n s e t o l a r g e w i n t e r s t o r m w a v e s , and r e m a i n e d u n a f f e c t e d by s m a l l waves i n t h e summer. In c o n t r a s t , t h e l o n g s h o r e b a r i n f r o n t o f P r o f i l e D was d e f i n i t e l y f o r m e d by s m a l l summer waves ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) . The l a r g e b o u l d e r a r e a b e t w e e n P r o f i l e s E and F i s f l a t , and s u p p o r t s t h i c k bed s o f k e l p . A l t h o u g h i t o c c u p i e s a r o u g h l y e q u i v a l e n t p o s i t i o n r e g a r d i n g bay symmetry t o t h e e l o n g a t e b o u l d e r b e d d e s c r i b e d a b o v e , i t s e x p o s u r e i s due t o a d i f f e r e n t s e t o f f a c t o r s . S m a l l e r waves a f f e c t t h i s a r e a ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) , and i t l i e s i n s h a l l o w e r w a t e r . P r e s u m a b l y t h i s a r e a r e p r e s e n t s t h e s o u r c e o f s and f o r b e a c h a c c r e t i o n and b a r b u i l d i n g d u r i n g t h e summer, and i n w i n t e r i t becomes c o v e r e d w i t h s and as a r e s u l t o f b e a c h d e -g r a d a t i o n . S m a l l b o u l d e r a r e a s on t h e f l a n k s o f Sand P o i n t p r o b a b l y r e s u l t f r o m s i m i l a r c i r c u m s t a n c e s . In summer, s and i s t r a n s p o r t e d f r o m t h e s e a r e a s o n t o t h e p o i n t by c o n v e r g i n g wave t r a i n s i n t h e l e e o f S e a l R o c k , t h u s s u p p l e m e n t i n g t h e l i t t o r a l d r i f t p a t t e r n w h i c h e x i s t s i n t h i s a r e a ( s e e c h a p t e r s on SEDIMENT S I ZE ANALYSES and SAND MOVEMENT BASED ON WAVE PARA-METERS ) . In w i n t e r , a l l t h i s s a n d i s t r a n s p o r t e d o u t b e y o n d S e a l Rock t o b u i l d t h e s h o a l a r e a p r e s e n t t h e r e . . The l a r g e b e d r o c k and b o u l d e r a r e a n e a r P o c k e t B e a c h 19. has p o s i t i v e r e l i e f , and i t s l a c k o f s and i s due t o w i n n o w i n g by c u r r e n t s and waves . B e d r o c k a r e a s , where no t e x p o s e d a t t h e s u r f a c e as s m a l l i s l a n d s , a r e a l l t r u n c a t e d a t a d e p t h o f 40 f e e t ( P l a t e 3 - l i n e GL-1 I I ) . The r e a s o n f o r t h i s i s not known. I t may be a r e s u l t o f g l a c i a l d e c a p i t a t i o n , o r e l s e wave e r o s i o n d u r i n g a s t i l l s t a n d i n s e a l e v e l d u r i n g H o l o c e n e t i m e s . B. OFFSHORE TROUGH C o n t i n e n t a l s h e l f b a t h y m e t r y o f f s h o r e f r o m Wreck Bay i s shown i n F i g u r e 4. T h r e e e c h o - s o u n d i n g l i n e s were run a c r o s s t h e t r o u g h , a g a i n t o d e l i n e a t e d i f f e r e n t s e d i m e n t a r y f a c i e s i n d i c a t e d by s a m p l i n g . An EDO W e s t e r n S o n a r Mode l 185 was u s e d a b o a r d C a n a d i a n Nava l A u x i l i a r y V e s s e l LAYMORE. I n t e n s i t y o f t h e 1s t m u l t i p l e r e f l e c t i o n p r o v e d t o be d i a g n o s t i c ( F i g u r e 4 ) , and i n d i c a t e d s i l t y muds i n t he b o t t o m o f t h e t r o u g h , s and a l o n g i t s e d g e s , and g r a v e l on t o p o f La P e r o u s e Bank ( L i n e 3 , b e t w e e n t i m e s t a t i o n s 2145 and 2 2 1 5 ) . S t r o n g i n t e n s i t y p r o v e d t o be b e d r o c k c o v e r e d w i t h a t h i n v e n e e r o f r e l i c t g r a v e l s ( s e e c h a p t e r on COASTAL ROCKS). Maximum t r o u g h d e p t h i s a t 60 f a t h o m s l o c a t e d a t i t s head ( s a m p l e l o c a t i o n O S - 1 6 ) , and t h e s h a l l o w e s t d e p t h a t 50 f a t h o m s o c c u r s o v e r a b r o a d s i l l a r e a ( s a m p l e l o c a t i o n OS - 1 4 ) . The l a t t e r i s t h o u g h t t o be t h e l o c u s o f maximum c l a y p a r t i c l e d e p o s i t i o n a t t h e p r e s e n t t i m e ( s e e c h a p t e r on RECENT SEDIMENTS) . FIGURE 3 ECHO SOUNDING — WRECK BAY — 5 6 JULY 1968 Profile line extensions < P U Gr id l ines I G D NJ O FIGURE 4 ECHO SOUNDING - OFFSHORE TROUGH - 30 MAX 1968 FIRST MULTIPLE INTENSITY s t r o n g — — — — m o d e r a t e w * a k O P a b s e n t LINE 1 VERTICAL SCALE APPROX. : HORIZONTAL SCALE echo " V • 181S 1830 1845 191S 1920 LINE 2 2055 204S 2030 2015 50 •n , > 1945 LINE 3 211S echo l i r s t m u l t i p l e 2145 25 50 > I o 2 2242 22 P l a t e 3. Echograms o f some t r a v e r s e s In Wreck Bay . F o r l o c a t i o n o f t h e s e t r a v e r s e s , s ee F i g u r e 3. 23. IV. COASTAL ROCKS A. INTRODUCTION Rocks e x p o s e d a l o n g t h e s h o r e l i n e a t Wreck Bay have b e e n t e n t a t i v e l y named by M u l l e r and C a r s o n ( 1 9 6 9 ) , as t h e " T o f i n o G r e y w a c k e U n i t " . They a r e a p o o r l y s o r t e d a s s e m b l a g e o f s e d i m e n t a r y r o c k s r a n g i n g f r o m a r g i l l i t e s t o a r g i l l a c e o u s s a n d s t o n e s , and o u t c r o p i n t e r m i t t e n t l y a l o n g t h e west c o a s t o f V a n c o u v e r I s l a n d as a d i s c o n t i n u o u s p e r i p h e r a l b e l t . At t h e n o r t h e r n end o f t h e i s l a n d , t h e u n i t i s 3 ,000 f e e t t h i c k a t Kyuquot S o u n d , and 3 ,600 f e e t t h i c k a t Q u a t s i n o Sound ( S u t h e r -l a n d B r o w n , 1 9 6 6 ) . B. LOCAL D I STR IBUT ION, L ITH0L0GY AND STRUCTURE F l o r e n c i a I s l a n d and t h e s o u t h e r n p a r t o f Q u i s i t i s P o i n t a r e c h a r a c t e r i z e d by t h e a b s e n c e o f e x o t i c m a t e r i a l i n t h e s e d i m e n t s . The r o c k s a r e d a r k g r e y i s h - b r o w n , v e r y p o o r l y b e d d e d , i m p u r e s a n d s t o n e s , and c o n t a i n numerous l e n s e s o f b r o w n i s h - b l a c k m u d s t o n e ( P l a t e 4 a ) . S a n d s t o n e s f r o m s a m p l e s F I - 3 , F I - 8 , F l - l l , QP-2 and QP-3 ( F i g u r e 5) a r e a l l q u i t e s i m i l a r i n c o m p o s i t i o n , and f r o m v i s u a l e s t i m a t e s , c o n t a i n 15 - 2 0 % f e l d s p a r , 5 - 15% r o c k f r a g m e n t s , and more t h a n 15% m a t r i x ( P l a t e 4 c ) . . They t h e r e f o r e c o r r e s p o n d t o l i t h i c a r k o s e s and f e l s p a t h i c a r e n i t e s i n F o l k ' s (1968) c l a s s i f i c a t i o n . The p a r t i c l e s a r e a n g u l a r t o s u b - r o u n d e d , and c o n s i s t o f v a r y i n g p r o p o r t i o n s o f q u a r t z , c h e r t , K - f e l s p a r , p I a g i o c I a s e , b i o t i t e , m u s c o v i t e , e p i d o t e , h o r n b l e n d e , c I i n o p y r o x e n e , c h l o r i t e and 2k. o p a q u e m i n e r a l s . The q u a r t z i s p r e d o m i n a n t l y o f p l u t o n i c o r i -g i n ( s t r a i g h t e x t i n c t i o n ) , b u t v o l c a n i c ( r o u n d e d embayment s , and no m i c r o l i t e s ) and m e t a m o r p h i c ( u n d u l o s e e x t i n c t i o n ) v a r i e t i e s a r e p r e s e n t as w e l l . F e l s p a r s a r e h i g h l y a l t e r e d , m a i n l y t o s e r i c i t e , and o n l y 10 - 20% i s n o r m a l l y f r e s h . An i n c r e a s e i n g r a i n - s i z e t o w a r d s t h e n o r t h e a s t was n o t i c e d i n t h e s e s a m p l e s : QP-3 and F l-8 a r e v e r y f i n e - g r a i n e d , QP-2 i s f i n e - g r a i n e d , and F l-3 and F l - l l a r e m e d i u m - g r a i n e d . The m a t r i x c o n s i s t s o f c l a y , c h l o r i t e and s e r i c i t e . i n t h i n s e c t i o n a few m i c r o - s t r u c t u r e s a r e e v i d e n t . Samp le FI -3 a p p e a r e d t o be w e a k l y g r a d e d , and FI -8 showed a i i n c h deep e r o s i o n c h a n n e l , w h i c h was f i l l e d w i t h m a t e r i a l i d e n t i c a l t o t h a t b e l o w . The o t h e r s a m p l e s a r e m a s s i v e and s t r u c t u r e l e s s . A l l o f them e x h i b i t i r r e g u l a r s h e a r - s t r i n g e r s c a r r y i n g i r o n - o x i d e , and t h e s e i n t u r n , a r e c u t by w ide t e n s i o n f r a c t u r e s c o n t a i n i n g c a l c i t e . L a r g e s c a l e f o l d i n g was r a r e l y s e e n e x c e p t on F l o r e n c i a I s l a n d ( P l a t e ka)„ H e r e , n e a r s a m p l e l o c a t i o n F l - l l , an o v e r t u r n e d a n t i c l i n e , w i t h l i m b s s h o w i n g c o n s t a n t t h i c k n e s s o f c o m p e t e n t s a n d s t o n e , s u g g e s t s a c o n c e n t r i c t y p e o f f o l d i n g . H o w e v e r , t h e t i g h t n e s s o f t h e f o l d , a n d c r u s h e d s t a t e o f mud-s t o n e i n t h e c o r e , i n d i c a t e t h a t i t more l i k e l y r e p r e s e n t s a s lump s t r u c t u r e , d e v e l o p e d when t h e s e d i m e n t s were s t i l l i n a s e m i - c o n s o I i d a t e d s t a t e . No m e a s u r e m e n t s on t h e p l u n g e were p o s s i b l e , b u t t h e f o l d i s r ecumbent t o t h e e a s t . 25. F a u l t i n g seems t o h a v e b e e n much more s i g n i f i c a n t t h a n f o l d i n g , i n t h e d e f o r m a t i o n o f t h e s e s e d i m e n t s . M ost o f t h e f a u l t s t r e n d n o r t h - e a s t w a r d s , and d i p s t e e p l y t o w a r d s t h e n o r t h w e s t (Map I ) , L o c a l l y , c o m p e t e n t s a n d s t o n e s h a v e been m y l o n i t i z e d by i n t e n s e s h e a r i n g ( P l a t e kb)„ S a m p l e s QP-1 I , WP-3 and WP^-13 ( F i g u r e 5) were a l s o s a n d s t o n e s , b u t had b e e n s t r o n g l y m o d i f i e d f r o m t h e g e n e r a l : p i c t u r e p r e s e n t e d a b o v e . QP-1 I i s an i n t e n s e l y s h e a r e d s e q u e n c e o f r e l a t i v e l y t h i n s a n d s t o n e and b l a c k a r g i l l i t e b a n d s , I n t o w h i c h c a l c i t e and i r o n - o x i d e h a v e a p p a r e n t l y been d e p o s i t e d t o g e t h e r a l o n g t h e f r a c t u r e s . M i n u t e p y r i t e c u b e s and p y r r h o -t i t e n o d u l e s l i e embedded i n t h e c a l c i t e , and e p i d o t e has b e e n f o r m e d i n i s o l a t e d p a t c h e s , t h u s i n d i c a t i n g l o w - g r a d e m e t a m o r p h i s m i n t h i s a r e a . S ample WP-3 i s a l s o i n t e n s e l y s h e a r e d , and comes f r o m a f a u l t z o n e t r e n d i n g p a r a l l e l t o t h e c o a s t , t h a t has been i m p r e g n a t e d w i t h i r o n - o x i d e . Q u a r t z p a r -t i c l e s e x h i b i t c r e n u l a t e d b o r d e r s , u n d u l o s e e x t i n c t i o n , and a l i g n m e n t o f t h e i r l o n g e s t a x e s p a r a l l e l t o t h e s h e a r p l a n e s ; f e l s p a r s a r e a l l h i g h l y a l t e r e d . S a mple WP-13 t y p i f i e d much o f Wya P o i n t , i n t h a t c h e r t n o d u l e s and t h i n c h e r t b a n d s c o n -s t i t u t e d up t o 5 0 % o f t h e r o c k v o l u m e ( P l a t e 5 a ) . C a l c i t e was a l s o p r e s e n t i n s i g n i f i c a n t a m o u n t s , as f r a c t u r e f i l l i n g s , and l o c a l l y r e p l a c i n g q u a r t z . The s o u t h e a s t c o r n e r o f Wreck Bay i s i s o l a t e d f r o m P o c k e t B e a c h by a p i l l o w e d l a v a f l o w ( P l a t e 5 b ) . M o r e commonly 26. i t i s b r e c c i a t e d , and c o n t a i n s b l o c k y g r e y c h e r t . Nowhere was i t s e e n i n c o n t a c t w i t h t h e s a n d s t o n e s , and t h e r e f o r e i t s age r e l a t i o n s h i p i s unknown. I f t h e s i z e and s h a p e o f p i l l o w s c a n be c o n s i d e r e d a d i a g n o s t i c c r i t e r i o n , t h e y were i d e n t i c a l t o p i l l o w s s een i n K a r m u t s e n b a s a l t s on t h e n o r t h s i d e o f Kennedy L a k e . In t h i n - s e c t i o n , t h e r o c k i s c o m p l e t e l y a l t e r e d t o f i b r o u s a m p h i b o l e ( u r a l i t e ) , b u t s t i l l p r e s e r v e d a r e a few s m a l l a m y g d u l e s l i n e d w i t h c h l o r i t e , and f i l l e d w i t h z e o l i t e s ( Samp le W P - I ) . No m a g n e t i t e i s p r e s e n t , b u t t h e f e l t y g r o u n d -mass i s c r i s s - c r o s s e d by a g r e a t number o f c h l o r i t e v e i n s . T h e s e i n t u r n a r e c u t by q u a r t z , and l a t e r by c a r b o n a t e v e i n -l e t s . S e a l Rock c o n s i s t s o f a s i n g u l a r , u n i q u e r o c k t y p e . I t i s v e r y f i n e g r a i n e d and p a l e g r e e n i n c o l o u r , and i n t h i n s e c t i o n , a c r y p t o c r y s t a I I i n e f e l t y mass c o m p l e t e l y masks i t s o r i g i n a l i d e n t i t y ( S amp le S R - I ) . S c a t t e r e d t h r o u g h t h i s mass a r e t i n y a c i c u l a r c r y s t a l s w i t h p r e f e r r e d o r i e n t a t i o n , and a g r e a t many i r r e g u l a r f r a c t u r e s c o n t a i n c a l c i t e . I t i s t h o u g h t t o be an a l t e r e d t u f f , and p o s s i b l e c o r r e l a t e s w i t h t h e B o n a n z a G r o u p . C. EXOTIC MATERIAL Wya P o i n t s a n d s t o n e s , and t o a l e s s e r e x t e n t t h e m i d d l e and n o r t h e r n p a r t s o f Q u i s i t i s P o i n t , a r e c h a r a c t e r i z e d by e x o t i c b l o c k s o f c h e r t and m a r b l e . The o r i g i n o f t h i s m a t e r i a l i s unknown, b u t t h e l a r g e d i m e n s i o n s o f some o f t h e s e 27. b l o c k s s u g g e s t t h a t t h e y were t r a n s p o r t e d o v e r a r e l a t i v e l y s h o r t d i s t a n c e . S amp le s Q P - 4 , WP -31 , WP,-25 and WP-12 were o b -t a i n e d f r o m c h e r t . QP-4 i s a p a l e g r e e n i s h - g r e y , m o t t l e d c h e r t , c o n s i s t i n g o f c r y p t o c r y s t a I I i n e q u a r t z w i t h s c a t t e r e d " c o n -c r e t i o n s " o f m i c r o c r y s t a l l i n e q u a r t z , show ing u n d u l o s e e x -t i n c t i o n . T h e s e c o n c r e t i o n s may be r e c r y s t a I I i z e d r a d i o l a r i a n t e s t s , as v e i n l e t s o f i r o n - o x i d e do no t a p p e a r t o p a s s t h r o u g h them ( P l a t e 6 b ) . A number o f c l e a r q u a r t z s t r i n g e r s c u t t h e i r o n - o x i d e v e i n l e t s , and e l s e w h e r e , a p p e a r t o be c u t by them. S a m p l e WP-3I came f r o m a c h e r t o u t c r o p w h i c h a p p e a r e d t o o c c u p y most o f t h e s o u t h e r n b o u n d a r y o f P o c k e t B e a c h . I t i s d a r k g r e y i n c o l o u r , and c o n t a i n s numerous e l o n g a t e " c o n -c r e t i o n s " w h i c h a r e p e r h a p s r e c r y s t a I I i z e d sponge s p i c u l e s . B o t h q u a r t z and i r o n - o x i d e v e i n l e t s a r e p r e s e n t , b u t b o t h a r e c u t and l o c a l l y r e p l a c e d by c a l c i t e v e i n s . S amp le WP-25 came f rom a l a r g e b l o c k o f l a m i n a t e d c h e r t s how ing s m a l l - s c a l e f o l d i n g ( P l a t e 6 a ) . I t i s i d e n t i c a l t o s a m p l e QP-4 e x c e p t t h a t " c o n c r e t i o n s " a r e much more a b u n d a n t , and no i r o n - o x i d e v e i n l e t s a r e p r e s e n t . Q u a r t z - f i I Ied f r a c t u r e s a r e a l s o somewhat w i d e r , w i t h s m a l l c r y s t a l s o r i e n t e d p e r p e n d i c u l a r t o and a d j a c e n t t o t h e e d g e s , and l a r g e i n t e r l o c k i n g c r y s t a l s w i t h u n d u l o s e e x -t i n c t i o n i n t h e m i d d l e . S amp le WP-12 i s f r om a n o d u l e c o n t a i n e d i n t h e s a n d s t o n e ( P l a t e 5 a ) . The w e a t h e r e d e x t e r i o r i s w h i t e , b u t a f r e s h l y b r o k e n s u r f a c e p o s s e s s e s a m e d i u m - g r e y c o l o u r . In t h i n s e c t i o n i t i s i d e n t i c a l t o WP-31 , e x c e p t t h a t c a r b o n a t e 28. v e i n l e t s a r e more a b u n d a n t . L a r g e e x o t i c b l o c k s o f r e c r y s t a I I i z e d l i m e s t o n e o c c u r a t s a m p l e l o c a t i o n s WP-9 and WP-30. WP-9 i s an i r r e g u -l a r l y s h a p e d body w i t h b u l b o u s p r o t u b e r a n c e s e x t e n d i n g i n t o t h e s a n d s t o n e ( P l a t e 7 a ) , w h e r e a s WP-30 i s o v a l s h a p e d . They a r e b o t h g r e y i s h - w h i t e i n c o l o u r , and c o n s i s t o f f i n e - g r a i n e d i n t e r l o c k i n g c a l c i t e c r y s t a l s . I r r e g u l a r and i n t e r s e c t i n g s h e a r z o n e s have r e s u l t e d i n l o c a l r e c r y s t a I I i z a t i o n t o l a r g e t w i n n e d IameI I a ( P l a t e 7 b ) , t h e l a t t e r o f t e n b e i n g b e n t . In s a m p l e WP-30 , t h e c r y s t a l s e x h i b i t p r e f e r r e d a l i g n m e n t ( P l a t e 7 b ) , w h e r e a s WP-9 c o n s i s t s o f a m o s a i c o f e q u a n t g r a i n s . F u r t h e r m o r e , s a m p l e WP-30 i s c u t by s e v e r a l i r o n - o x i d e v e i n -l e t s , w h e r e a s WP-9 i s n o t . S amp le WP-7 i s c o a r s e g r a i n e d , p a l e g r e y , and has t h e a p p e a r a n c e o f an i n t r u s i v e r o c k . The s a m p l e l o c a t i o n was s e p a r a t e d f r o m s a n d s t o n e s t o t h e n o r t h e a s t by a s h a r p c o n t a c t , w h e r e a s t h e o t h e r b o u n d a r i e s were i n d i s c e r n i b l e . S e v e r a l o t h e r s m a l l o c c u r r e n c e s o f t h i s m a t e r i a l a r e e x p o s e d be tween t h i s l o c a t i o n , and t h e end o f t h e p r o m o n t o r y . In t h i n - s e c t i o n , i t c o n s i s t s o f c o a r s e g r a i n e d i n t e r l o c k i n g m e t a m o r p h i c q u a r t z g r a i n s , h i g h l y a l t e r e d f e l s p a r , a b u n d a n t l a r g e c h l o r i t e l a t h e s , and b l o t c h e s o f e p i d o t e . I t i s t h e r e f o r e a l o w - g r a d e r e g i o n a l l y m e t a m o r p h o s e d d e r i v a t i v e o f unknown s i l i c i o u s p a r e n t m a t e r i a l , t h a t was i n c o r p o r a t e d i n t o t h e T o f i n o G r e y w a c k e U n i t s i m i l a r t o o t h e r e x o t i c m a t e r i a l . 29. D. INTRUSIVES . Only one i n t r u s i v e body was found a l o n g the c o a s t a l s e c t i o n t h a t was examined. T h i s was an 8 f o o t wide d i a b a s e dyke (Map I) r e p r e s e n t e d by sample WP-26. I t c o n s i s t s o f l a b r a d o r i t e l a t h s showing a l i g n m e n t ( f l u i d a l t e x t u r e ) , and a few zoned e u h e d r a l f e l s p a r p h e n o c r y s t s , A u g i t e , p a r t i a l l y c h l o r i t i z e d , and m a g n e t i t e a r e the next most common c o n s t i t u e n t s 9 and o x i d a t i o n o f the l a t t e r has imparted a reddish-brown c o l o u r t o the weathered s u r f a c e . I t p r o b a b l y i s p a r t o f the b a s i c Kennedy I n t r u s i o n s o f Creta c e o u s o r T e r t i a r y age, d e s c r i b e d by Eastwood (19^ 8 ) . E. RELATIVE AGE S u t h e r l a n d Brown (1966) has a s s i g n e d a l a t e J u r a s s i c -e a r l y Cretaceous age t o the T o f i n o Greywacke U n i t ( C a l l o v i a -A p t i a n ) , i . e . 120-160 m i l l i o n y e a r s 3.P. Th i s c o n t e n t i o n i s i n d i r e c t l y s u p p o r t e d by a number o f f a c t o r s : 1. LOWER LIMIT I t s unmetamorphosed c o n d i t i o n and h i g h f e l s p a r con-t e n t , t o g e t h e r w i t h the f a c t t h a t i t c o n t a i n s a number o f low-grade r e g i o n a l metamorphic m i n e r a l s l i k e e p i d o t e , amphibole and c h l o r i t e , s u ggest t h a t i t was d e p o s i t e d a f t e r emplacement o f the Kennedy B a t h o l i t h , which has been dat e d a t 167 m i l l i o n y e a r s B.P. 2. UPPER LIMIT M u l l e r and Carson (1969) r e p o r t t h a t a q u a r t z - m o n z o n i t e 3 0 . s t o c k i n t r u d e s t h e u n i t on S t u b b s I s l a n d ( a c r o s s t h e i n l e t f r o m T o f i n o ) , w h i c h has been d a t e d as e a r l y T e r t i a r y , A l s o , t h e d i a b a s e dyke f o u n d c u t t i n g t h e u n i t on Wya P o i n t , i s most l i k e l y o f C r e t a c e o u s o r T e r t i a r y a g e . A g e n e r a l i z e d s t r a t i g r a p h i c c o l u m n o f r o c k s e x p o s e d a l o n g t h e c o a s t , and d i r e c t l y i n l a n d f r om Wreck B a y , i s g i v e n i n T a b l e IV. PERI0D UNI T L ITH0L0GY Q u a t e r n a r y WRECK BAY FORMATION G 1 a c i o f l u v i a l o u t w a s h and t i l l C r e t a c e o u s o r T e r t i a r y KENNEDY INTRUSIONS Basa11 and g a b b r o L a t e J u r a s s i c t o e a r l y C r e t a c e o u s TOFINO GREYWACKE UNI T A r g i l l a c e o u s s a n d -s t o n e s and m u d s t o n e s M i d d l e J u r a s s i c BATHOLITHIC INTRUSIONS (Kennedy B a t h o 1 i t h ) M a i n l y g r a n o d i o r i t e and q u a r t z m o n z o n i t e L a t e T r i a s s i c t o l ower Ju r a s s i c BONANZA GROUP P y r o c l a s t i c a n d e s i t e L a t e T r i a s s i c QUA T S IN0 GROUP M a s s i v e t o t h i n l y b e d d e d l i m e s t o n e , a r g i 1 l i t e and t u f f a -c e o u s a r g i 1 l i t e KARMUTSEN GROUP B r e c c i a t e d , a m y g d a l o i -da1 and p i 1 lowed b a s a l t s and a n d e s i t e Tab Ie IV - G e n e r a l i z e d s t r a t i g r a p h i c c o l u m n o f Rocks i n t h e V i c i n i t y o f Wreck Bay . 31, F. REGIONAL DISTRIBUTION AND RELATION TO PRESENT-DAY OFFSHORE  T R G U G H • The d e p o s i t i o n a l p a l e o s l o p e o f t h e T o f i n o G r e y w a c k e U n i t i s i n d i c a t e d by S u t h e r l a n d Brown ( 1966 ) as b e i n g d i r e c t l y s e a w a r d i n t h e v i c i n i t y o f Wreck B a y , and M u l l e r and C a r s o n ( 1969 ) n o t e t h a t t h e s e d i m e n t s d i p s t e e p l y t o w a r d s t h e s o u t h -w e s t . A p a r t f r o m t u f f c o m p o s i n g S e a l R o c k , and t h e l a v a f l o w n o r t h o f P o c k e t B e a c h , t h e s e c o a s t a l s e d i m e n t s a r e s e p a r a t e d f r o m K a r m u t s e n , Q u a t s i n o , B o n a n z a and B a t h o l i t h i c I n t r u s i o n s a r o u n d Kennedy L a k e , by a b r o a d b e l t o f u n c o n s o l i d a t e d g l a c i o -f l u v i a l o u t w a s h . Ea s twood ( 1 968 ) and M u l l e r and C a r s o n ( 1 9 6 9 ) have p r o p o s e d t h a t a m a j o r f a u l t u n d e r l i e s t h e s e g r a v e l s t o e x p l a i n t h e b r e a k i n b e d r o c k g e o l o g y . Ea s twood (1968 ) h o w e v e r , p o i n t s o u t t h a t t h i s f a u l t i s u n r e l a t e d t o a l l o t h e r f a u l t s i n t h e a r e a , b e c a u s e o f i t s n o r t h w e s t t r e n d . The n e c e s s i t y f o r t h i s i n f e r r e d f a u l t i s q u e s t i o n e d h e r e , on t h e b a s i s o f t h e f o l l o w i n g a r g u m e n t . S e d i m e n t s c o m p o s i n g t h e c o a s t a l r o c k s a r e d i s t i n c t l y g e o s y n c l i n a l i n c h a r a c t e r - t h e s a n d s t o n e s a r e f l y s c h - t y p e d e p o s i t s , and a l o n g Wya P o i n t , have b e e n m i x e d w i t h p r e - f l y s c h e x o t i c b l o c k s o f c h e r t and m a r b l e . A l t h o u g h A u b o u i n ( 1 965 ) s t a t e s t h a t t h e s e c o n s e c u t i v e s e d i m e n t a r y p e r i o d s n o r m a l l y p r e c e d e t h e a d v e n t o f a c i d i n t r u s i o n s , e v i d e n c e s u g g e s t s t h a t i n t h i s c a s e t h e s a n d s t o n e s were d e p o s i t e d a f t e r emp lacement o f t h e Kennedy B a t h o l i t h , and were i n f a c t l a r g e l y d e r i v e d t h e r e f r o m . The n o r t h e a s t e r n edge o f t h i s g e o s y n c l i n a l t r o u g h t h e n , n a t u r a l l y o v e r l i e s t h e a c i d i n t r u s i v e i n t h e 3 2 . r e g i o n now c o v e r e d by g I a c i o f I u v i a I o u t w a s h . C o n c e r n i n g t h e s e a w a r d e x t e n s i o n o f t h e s e s e d i m e n t s , two C o n t i n u o u s S e i s m i c P r o f i l e r e c o r d s o b t a i n e d by t h e U . B . C . M a r i n e G e o l o g y G roup were e x a m i n e d ( M u r r a y 1970, p e r s o n a l c o m m u n i c a t i o n ) . B o t h l i n e s e x t e n d f r o m a p o i n t l o c a t e d a p p r o x -i m a t e l y l\ n a u t i c a l m i l e s f r o m Wya P o i n t , # 6 7 - 2 6 o r i e n t e d norma l t o t h e c o a s t l i n e , and #67-27 p a r a l l e l t o i t i n a s o u t h -e a s t d i r e c t i o n (Map' 2 ) . The l a t t e r s i m p l y shows c r u m p l e d s e d i -ment , d i p p i n g g e n t l y s o u t h e a s t w a r d s a l o n g t h e b a s e o f t h e p r e s e n t - d a y o f f s h o r e t r o u g h , and u n d e r l y i n g a p p r o x i m a t e l y 100 f e e t o f u n d i s t u r b e d r e c e n t s e d i m e n t . Where t h e l i n e c r o s s e s t h e edge o f La P e r o u s e Bank j u s t n o r t h o f t i m e s t a t i o n 1930, t h e r e c o r d i s no t c l e a r ; h o w e v e r , on t h e s o u t h s i d e o f t h e bank where i t p a s s e s i n t o B a r k l e y Sound T r o u g h , f a u l t i n g i s c l e a r l y i n e v i d e n c e , and b a s e d on t h e b a t h y m e t r y , t h i s f a u l t c o n t i n u e s i n t o B a r k l e y Sound i n a n o r t h e a s t d i r e c t i o n . L i n e #67-26 t o o , shows c r u m p l e d s e d i m e n t d i p p i n g g e n t l y i n a s o u t h e r l y d i r e c t i o n a t t h e b a s e o f t h e o f f s h o r e t r o u g h . The u n c o n f o r m i t y b e t w e e n t h e s e c o n s o l i d a t e d s e d i m e n t s ( T o f i n o G r e y w a c k e U n i t ? ) and t h e o v e r l y i n g r e c e n t s e d i m e n t , i s a f a i r l y smooth p l a n e w h i c h a l s o d i p s g e n t l y s o u t h w a r d s . I t c o n t i n u e s u n d e r t h e s o u t h e r n r i m o f t h e p r e s e n t - d a y o f f s h o r e t r o u g h , w i t h no s i g n o f f a u l t i n g , u n t i l i t becomes masked by c l o s e l y s p a c e d m u l t i p l e r e f l e c t i o n s . At t i m e s t a t i o n 1830, i n d u r a t e d s e d i m e n t f o r m i n g t h e ba sement i s a g a i n v i s i b l e , and 33. d i p s m o d e r a t e l y s t e e p l y t o w a r d t h e n o r t h . T h i s r e g i o n may r e -p r e s e n t t h e s o u t h e r n b o u n d a r y o f t h e pa I e o g e o s y n c I i n a I t r o u g h i n t o w h i c h T o f i n o G r e y w a c k e U n i t s e d i m e n t s were d e p o s i t e d . Be tween t i m e s t a t i o n s 1830 and 1800, a s e c o n d t r o u g h i s j n d j s t i n c t l y s u g g e s t e d by t h e r e c o r d . The s e d i m e n t s c o m p o s -i n g t h i s t r o u g h a r e e i t h e r an e x t e n s i o n o f t h e T o f i n o G r e y -wacke U n i t a c r o s s an a n t i c l i n a l a r c h , o r e l s e c o n s i s t o f 0 1 i g o c e n e - M i o c e n e d e p o s i t s , i m p l i e d by S u t h e r l a n d Brown (1966) as e x i s t i n g i n t h i s a r e a . i t a p p e a r s t h e r e f o r e , t h a t t h e s o u t h e r n r i m o f t h e p r e s e n t - d a y o f f s h o r e t r o u g h i s , a t l e a s t i n p a r t , a r e s u l t o f u n c o n s o l i d a t e d d e t r i t a l f i l l , and t h a t i t s s l o p e o f 20 - 25 d e g r e e s r e p r e s e n t s t h e a n g l e o f r e p o s e o f t h i s m a t e r i a l . The s o u r c e o f t h e s e s e d i m e n t s was a l m o s t c e r t a r n f y t h e g l a c i a l d e p o s i t s o n L a f e r o u s e B a n k . A-s eea. l e v e l r o s e d u r i n g t h e Ho4c*cene P e r i o d , f i n e s a n d w o u l d be winnowed o u t o f t h e g l a c i a l d e p o s i t s by wave a c t i o n and swept l a n d w a r d , t o e v e n t u a l l y s p i l l i n t o t h e p r e s e n t - d a y t r o u g h . I n d i r e c t e v i d e n c e s u p p o r t i n g t h i s t h e o r y i s f u r n i s h e d b y : I r r e g u l a r i t y o f t h e 25 f a t h o m b a t h y m e t r i c l i n e on La P e r o u s e Bank (Map 2) i n d i c a t e s a b u n d a n c e o f g l a c i a l m a t e r i a l i n t h e f o r m o f e s k e r s , wherea s k a m e - k e t t l e t o p o g r a p h y a t o t h e h e a d o f t h e p r e s e n t - d a y t r o u g h ( l a t . 48 50 , l o n g , o , 125 50 - Map 2) s u g g e s t s r e l a t i v e l y l e s s g l a c i a l d e b r i s . Echogram L i n e 3 ( F i g u r e 4) has a m o d e r a t e f i r s t m u l t i p l e 34. r e f l e c t i o n i n t e n s i t y between t ime s t a t i o n s 2145 and 2215, c o n f i r m i n g the e x i s t e n c e o f a c o n s i d e r a b l e t h i c k n e s s o f u n c o n s o l i d a t e d m a t e r i a l on La Perouse Bank. The i n t e n s i t y o f f i r s t m u l t i p l e r e f l e c t i o n on L i n e s I, 2 and 3 at the head o f t he p r e s e n t - d a y t r ough i s s t r o n g , i n d i c a t i n g a t h i n u n c o n s o l i d a t e d s e d i m e n t a r y c o v e r above bed ro ck . Samples OS-19 and OS-20 from La Perouse Bank a r e r e l i c t g l a c i a l g r a v e l s c o n s i s t i n g a lmos t e n t i r e l y o f c o b b l e s and p e b b l e s , and appear i d e n t i c a l i n c o m p o s i t i o n and shape to t ho se found i n the g l a c i o f l u v i a l outwash a t Wreck Bay, A l t h o u g h no s e i s m i c r e c o r d s e x i s t a c r o s s t h e n o r t h -e rn r im o f t he p r e s e n t - d a y o f f s h o r e t r o u g h , i t i s r e a s o n a b l e to assume t h a t t h i s 15 - 20 degree s l o p e a l s o r e p r e s e n t s t he a n g l e o f repose o f r e cen t d e t r i t u s . C o n s i d e r i n g the amount o f f i n e g r a i n e d m a t e r i a ! w h i c h h-as b e e n removed f rom Wreck Bay and Long B e a c h , and assuming t h a t t he p r e s e n t s o u t h e a s t moving n e a r s h o r e c u r r e n t has p e r s i s t e d s i n c e the end o f t he H o l o c e n e , i n f i l l i n g o f t he n o r t h e r n f l a n k o f the o l d T o f i n o Greywacke U n i t d e p o s i t i o n a l b a s i n i s r e a d i l y e x p l a i n e d . In summary t h e n , the d e p o s i t i o n a l b a s i n o f t h e T o f i n o Greywacke U n i t i n t he v i c i n i t y o f Wreck Bay, was a na r row g e o s y n c l i n a l t r ough wh ich ex tended p a r a l l e l t o t he p r e s e n t - d a y c o a s t I i n e , T h e n o r t h e r n edge i s exposed a l ong the s h o r e , and based on i n c r e a s i n g g r a i n s i z e o f s ands tones towards t h e n o r t h e a s t , and abundance o f e x o t i c b l o c k s a l ong Wya P o i n t , t he s o u r c e o f t h e s e sed iment s was p r o b a b l y t he mounta inous 35. h i n t e r l a n d n o r t h e a s t o f Kennedy L a k e . The s o u t h e r n edge o f t h e g e o s y n c l i n a l t r o u g h , as s u g g e s t e d by s e i s m i c p r o f i l e #67-26, may l i e a l o n g La P e r o u s e Bank a t t i m e s t a t i o n 1830, a d i s t a n c e o f a p p r o x i m a t e l y 5i n a u t i c a l m i l e s f r o m Wya P o i n t . P l e i s t o c e n e c o n t i n e n t a l g l a c i e r s a p p e a r t o have p a s s e d r i g h t a c r o s s t h i s p a l e o t r o u g h , as e v i d e n c e d by t h e g e n t l y s o u t h w a r d d i p p i n g juncontfiortni ty« a t t h e b a s e o f t h e p r e s e n t - d a y o f f s h o r e t r o u g h , and a b u n d a n c e o f g l a c i a l d e b r i s on t o p o f La P e r o u s e Bank . The p r e s e n t - d a y o f f s h o r e t r o u g h o c c u p i e s t h e m i d d l e o f t h e p a l e o t r o u g h as a r e s u l t o f i n f i l l i n g f r o m t h e s o u t h by s e a l e v e l t r a n s g r e s s i o n o v e r t h i s g l a c i a l d e b r i s , and i n f i l l i n g f r o m t h e n o r t h due to e r o s i o n o f g I a c i o f I u v i a I o u t w a s h f r o m Wreck Bay and Long B e a c h . The g e o m e t r i c s h a p e o f t h e p r e s e n t -day o f f s h o r e t r o u g h r e f l e c t s t h e c o n t r a s t i n g a b u n d a n c e s o f g l a c i a l m a t e r i a l o n La P e r o u s e B a n k , and on t h e bank- a t i t s h e a d . 36 in Tofino 5 4 3 2 Ucluelet S A M P L E L O C A T I O N S QP QUISITIS POINT WP WYA POINT SR SEAL ROCK FI FLORENCIA ISLAND LSC LOST SHOE CREEK • sand o r gravel X rock FIGURE 5 S C A L E 1 2 Miltr 1.25 Inches t» 1 Mile approjcimtttiy P l a t e 4 a . T i g h t l y f o l d e d i m p u r e s a n d s t o n e and i n c o m p e t e n t b r o w n i s h - b l a c k m u d s t o n e . S amp le l o c a t i o n F l - l l . P l a t e 4 b . M y l o n i t i z e d s a n d s t o n e . Samp le l o c a t i o n F l-8. P l a t e 4 c . P h o t o m i c r o g r a p h o f m e d i u m - g r a i n e d impure s a n d s t o n e . A n g u l a r t o s u b - r o u n d e d q u a r t z , c h e r t , p l a g i o c l a s e , a l t e r e d f e l s p a r , m u s c o v i t e and b i o t i t e c a n be i d e n t i f i e d . S amp le l o c a t i o n F l - l l . P l a t e 5 a . C h e r t n o d u l e s and bands i n i m p u r e s a n d s t o n e . S a m p l e l o c a t i o n WP-12 and WP-13. P l a t e 5 b . P i l l o w s t r u c t u r e s i n an a l t e r e d l a v a f l o w , b e t w e e n t h e s o u t h e a s t c o r n e r o f Wreck B a y , and t h e P o c k e t B e a c h . Samp le l o c a t i o n WP- I . 38. P l a t e 6 a , L a m i n a t e d c h e r t s how ing s m a l l - s c a l e f o l d i n g , , S amp le l o c a t i o n WP-25. P l a t e 6b. P h o t o m i c r o g r a p h o f c h e r t s how ing " c o n c r e t i o n s " o f u n d u l o s e q u a r t z , i r o n - o x i d e , and q u a r t z v e i n l e t s . S amp le l o c a t i o n Q P - 4 . 39. P l a t e 7 a . L a r g e b l o c k o f m a r b l e w i t h b u l b o u s p r o t u b e r a n c e s p r o j e c t i n g i n t o t h e i m p u r e s a n d s t o n e . Samp le l o c a t i o n WP-9. P l a t e 7 b . P h o t o m i c r o g r a p h o f m a r b l e s h o w i n g a l i g n m e n t o f s m a l l c a l c i t e g r a i n s , and l a r g e t w i n n e d l a m e l l a i n v i c i n i t y o f s h e a r z o n e . Samp le l o c a t i o n WP-30. 4 1 . V. RECENT SEDIMENTS A. INTRODUCTION. G I a c i o f I u v i a I o u t w a s h , c o m p o s i n g most o f t h e c o a s t a l p i a i n a l o n g t h e west c o a s t o f V a n c o u v e r I s l a n d , and b e s t e x p o s e d a t Wreck B a y , was named by Do Image (1919) as t h e Wreck Bay F o r m a t i o n . The m i n e r a l o g y o f t h i s d e p o s i t and r e c e n t s e d i m e n t s d e r i v e d t h e r e f r o m , were s t u d i e d u s i n g two d i f f e r e n t t e c h n i q u e s . The v e r y f i n e s and f r a c t i o n ( 6 2 . 5 - 1 25.O/0 , w h i c h c o n t a i n e d a l m o s t a l l t h e m a g n e t i t e and a l a r g e p e r c e n t a g e o f o t h e r h e a v y m i n e r a l s , was i s o l a t e d f o r p o i n t - c o u n t a n a l y s i s . S i l t s ( 2 . 0 - 62.5/*) and c l a y s (<2.0yu) were s e p a r a t e d f o r X - r a y d i f f r a c t i o n a n a l y s i s . S amp le s s e l e c t e d f o r t h e two i n v e s t i g a t i o n s o v e r l a p t o a d e g r e e , as shown i n T a b l e V. F o r p o i n t - c o u n t a n a l y s i s , o n e s a m p l e was a r b i t r a r i l y s e l e c t e d f r o m f o u r t e e n e n v i r o n m e n t s i n o r d e r t o g a i n an i m p r e s s i o n o f t h e i r a s s o c i a t i o n and p r o -v e n a n c e . X - r a y a n a l y s i s was c o n d u c t e d on m a t e r i a l f r o m two s p e c i f i c r e g i o n s , t h e s e a c l i f f and o f f s h o r e t r o u g h , t o e x a m i n e t h e i r a f f i n i t y r e g a r d i n g r e c e n t s e d i m e n t d i s p e r s i o n . Sand c o a r s e r t h a n 125/^ c o n s i s t e d m a i n l y o f q u a r t z , f e l s p a r , r o c k f r a g m e n t s and s h e l l - h a s h ; no q u a n t i t a t i v e m i n e r -a l o g i c s t u d y was made on t h i s m a t e r i a l . G r a v e l s (>2.0 mm) t o o , were s i m p l y n o t e d f o r t h e i r c h a r a c t e r t o s u p p l e m e n t e v i d e n c e on t h e p r i m a r y s o u r c e o f t h e s e d i m e n t s . F o r s a m p l i n g p r o c e d u r e s and t h e i r l o c a t i o n s , s ee APPENDIX. 42 . B. POINT-COUNT ANALYSIS 1. LABORATORY PROCEDURE V e r y f i n e s and f r a c t i o n s were s c r e e n e d f r om 14 s e l e c t e d s a m p l e s t o d e t e r m i n e t h e i r w e i g h t p e r c e n t a g e s ( co l umn I, " f ab l e V I ) . M a g n e t i t e was t h e n s c r e e n e d f r o m t h e s e s i z e f r a c t i o n s and e x p r e s s e d as w e i g h t p e r c e n t a g e s ( c o l u m n 2, T a b l e V I ) . The b a l a n c e was t h e n s e p a r a t e d i n t o h e a v y and l i g h t m i n e r a l f r a c t i o n s u s i n g b r o m o f o r m ( S . G . = 2 .9 ) f o r p o i n t - c o u n t ana l y s i s . Twenty e i g h t t h i n - s e c t i o n s were p r e p a r e d , one e a c h f o r t h e l i g h t and heavy m i n e r a l s . A p p r o x i m a t e l y 300 g r a i n c o u n t s were made on b o t h l i g h t and h e a v y m i n e r a l t h i n - s e c t i o n s , and m i n e r a l p r o p o r t i o n s were c a l c u l a t e d as p e r c e n t a g e s o f t o t a l s a m p l e c o u n t s ( T a b l e V I ) . 2. RESULTS C o n c e r n i n g T a b l e V I , t h e n o n - m a g n e t i c o p a q u e c o l u m n c o n t a i n e d l e s s t h a n 5% r u t i l e , and t h e r e s t , t h o u g h u n i d e n t i -f i e d , was p r o b a b l y h e m a t i t e . G a r n e t , z i r c o n , e p i d o t e / c I i n o -z o i s i t e , h o r n b l e n d e and c h l o r i t e have d i a g n o s t i c o p t i c a l p r o p e r t i e s , and were r e a d i l y i d e n t i f i e d . The a u g i t e / d i o p s i d e c o l u m n c o n s i s t e d o f e q u a l p r o p o r t i o n s o f b o t h m i n e r a l s f o r t h e C l i f f s a m p l e , w h e r e a s a l l o t h e r s a m p l e s c o n t a i n e d r o u g h l y 75% d i o p s i d e . No a t t e m p t was made t o d i f f e r e n t i a t e t h e v a r i o u s t y p e s o f q u a r t z , h o w e v e r , g l a s s y p l u t o n i c m a t e r i a l made up t h e b u l k o f t h e c o l u m n . M l c r o c r y s t a l I i n e and c h a l c e d o n i c q u a r t z 4 3 . v a r i e t i e s were g r o u p e d i n t h e c h e r t c o l u m n . F e l s p a r s were g e n e r a l l y h i g h l y a l t e r e d t o s e r i c i t e and p o s s i b l y k a o l i n i t e , so b o t h K - f e l s p a r and p l a g i o c l a s e were d e t e r m i n e d u n d e r o n e c o l u m n . M u s c o v i t e and b i o t i t e o c c u r r e d i n t h e l i g h t and h e a v y m i n e r a l t h i n - s e c t i o n s ; g r a i n - c o u n t s f r o m b o t h were t h u s added t o g e t h e r , g i v i n g t h e f i g u r e s shown i n t h e c o l u m n . The c o l u m n h e a d e d by " U " i n c l u d e s unknown m i n e r a l s , m i n e r a l s not c o n s i d -e r e d i n t h e c o u n t i n g , and r o c k f r a g m e n t s ; a l a r g e p r o p o r t i o n o f t h e s e g r a i n s were p r o b a b l y a l t e r e d f e l s p a r s . 3. D lSCUSS ION (a ) M l n e r a l o g i c A s s o c i a t i o n s G r e y c l a y and g l a c i o f l u v i a l o u t w a s h e x p o s e d i n t h e c l i f f , p r o v i d e d t h e m a t e r i a l f o r a l l o t h e r s e d i m e n t a r y e n v i r o n m e n t s c o n s i d e r e d i n t h i s s t u d y . I t i s t h e r e f o r e a p p a r e n t t h a t t h e l a t t e r s e d i m e n t s h a v e b e e n a f f e c t e d by a t l e a s t two c y c l e s o f d e p o s i t i o n . F i r s t a c o m p a r i s o n o f t h e two " p a r e n t " c l i f f m a t e r i a l s , g r e y c l a y and g I a c i o f I u v i a I o u t w a s h . The l a t t e r , f r o m T a b l e V I , c o n t a i n s a h i g h e r p r o p o r t i o n o f m i c a and h e a v y m i n e r a l s , p a r t i c u l a r l y m a g n e t i t e , and somewhat l e s s q u a r t z , t h u s s u p p o r t i n g t e x t u r a l e v i d e n c e t h a t t h e ou twash t r a n s -p o r t i n g medium had a h i g h c o m p e t e n c y . Brown c l a y , w h i c h o c c u r s a t t h e c o n t a c t b e t w e e n t h e s e two m a t e r i a l s ( P l a t e s 8a and 8 b ) , i s an a l t e r a t i o n p r o d u c t o f tbe g r e y c l a y . C o n t a m i -n a t i o n o f i t s v e r y f i n e s a n d , s i l t and c l a y f r a c t i o n s by t h e o v e r l y i n g g I ac i o f l u v i a I o u t w a s h i s r e a d i l y a p p a r e n t i n T a b l e s VI and V I I , a l t h o u g h i t s low m a g n e t i t e c o n t e n t b e l i e s i t s t r u e n a t u r e . The b o u l d e r , w h i c h i s an u n a r m o u r e d m u d b a l l , m e a s u r e d a p p r o x i m a t e l y 9 i n c h e s i n d i a m e t e r . A l a r g e number o f t h e s e i n c l u s i o n s a r e c o n t a i n e d i n t h e g I a c i o f I u v i a I o u t w a s h c l o s e t o t h e c o n t a c t w i t h brown c l a y , and t h e r e f o r e p r o b a b l y o r i g i n a t e d f r om t h e g r e y c l a y d u r i n g i n i t i a l s t a g e s o f o u t w a s h d e p o s i t i o n . I t s v e r y f i n e s and f r a c t i o n i s n o t i c e a b l y d e f i c i e n t i n a l l m i n e r a l c o m p o n e n t s e x c e p t m i c a , w h i c h was most l i k e l y d e r i v e d f r o m t h e o u t w a s h w h i l e b e i n g r o l l e d a l o n g g l a c i a l s t r e a m c h a n n e l s . The s a m p l e f r o m L o s t Shoe C r e e k d i f f e r e d v e r y l i t t l e f rom t h e c l i f f o u t w a s h s a m p l e . O n l y z i r c o n and m i c a c o n c e n -t r a t i o n s were i n c r e a s e d as a r e s u l t o f r e c e n t f l u v i a l p r o -c e s s e s . Of t h e t h r e e b e a c h s a m p l e s s t u d i e d , one r e p r e s e n t s m a t e r i a l a f f e c t e d by l a r g e waves d u r i n g t h e w i n t e r r e g i m e (NWR-2a) , and t h e o t h e r two r e p r e s e n t m a t e r i a l d e p o s i t e d by s m a l l w a v e s . d u r i n g t h e summer r e g i m e (NWR-2b, NWR-2c) . NWR-2a i s c h a r a c t e r i z e d by e x c e e d i n g l y l i t t l e v e r y f i n e s a n d , a l a r g e p r o p o r t i o n o f w h i c h i s made up o f m a g n e t i t e and n o n -m a g n e t i c o p a q u e s . I t a l s o c o n t a i n s a h i g h p r o p o r t i o n o f t h e more r e s i s t a n t heavy m i n e r a l s s u c h as g a r n e t , z i r c o n and d i o p s i d e , t h u s r e f l e c t i n g t h e h i g h e n e r g y e n v i r o n m e n t p r e v a l e n t d u r i n g w i n t e r ( s e e c h a p t e r on ECONOMIC GEOLOGY, f o r g o l d c o n -c e n t r a t i o n i n t h i s r e g i o n ) . The v e r y f i n e s a n d c o m p o s i t i o n o f f i v e s a m p l e s c o l -l e c t e d b e t w e e n t h e u p p e r f o r e s h o r e and t h e o f f s h o r e t r o u g h , f s g e n e r a l l y q u i t e c o n s i s t e n t , a p a r t f o r a few s i g n i f i c a n t d i f f e r e n c e s . T h e s e s a m p l e s i n c l u d e NWR-2b, NWR-2c, B-19, OS-k and O S - 1 6 , and c o v e r a d i s t a n c e o f abou t 8 n a u t i c a l m i l e s . In c o m p a r i s o n t o c l i f f m a t e r i a l , t h e g r o u p shows a d e c r e a s e i n f e l s p a r and m i c a c o n t e n t ; and s t a r t i n g w i t h a r e l a t i v e l y h i g h z i r c o n c o n c e n t r a t i o n f o r t h e b e a c h s a m p l e s , t h e l a t t e r m i n e r a l shows p r o g r e s s i v e i m p o v e r i s h m e n t f u r t h e r away f r o m s h o r e . F u r t h e r m o r e , t h e ( a u g i t e + d i o p s i d e ) / h o r n b l e n d e r a t i o f o r t h e g r o u p shows an i n c r e a s e f r o m a b o u t 0 .5 t o 1.0 as c o m p a r e d t o t h e c l i f f . The most s i g n i f i c a n t d e p a r t u r e s f r o m t h e g e n e r a l g r o u p c o m p o s i t i o n o c c u r w i t h s a m p l e s NWR-2b and O S - 4 . The f o r m e r was t a k e n f r o m t h e u p p e r f o r e s h o r e n e a r t h e swash l i m i t , where w a t e r movement i s p r e d o m i n a n t l y by l a m i n a r f l o w ; t h e s a m p l e t h e r e f o r e c o n t a i n s a low p r o p o r t i o n o f m a g n e t i t e and o t h e r h e a v y m i n e r a l s . Samp le OS-k on t h e o t h e r hand has a v e r y h i g h m a g n e t i t e c o n t e n t and i s e n r i c h e d w i t h o t h e r h e a v y m i n e r a l s as w e l l , t h u s s u g g e s t i n g t h e p r e s e n c e o f a r e l i c t b e a c h p l a c e r a t t h i s 20 f a t h o m b a t h y m e t r i c l e v e l ( s e e c h a p t e r on ECONOMIC GEOLOGY). The Long B e a c h s a m p l e was c o l l e c t e d f r o m a h i g h e n e r g y e n v i r o n m e n t s i m i l a r t o t h a t r e p r e s e n t e d by s a m p l e NWR-2a i n Wreck B a y , i . e . f r o m t h e b a c k s h o r e . A l t h o u g h i t c o n t a i n s a h i g h c o n c e n t r a t i o n o f n o n - m a g n e t i c o p a q u e m i n e r a l s and 46. ( a u g i t e + c ! : o P s i d e ) , i t i s r e l a t i v e l y s p a r s e i n m a g n e t i t e . In t h e l i g h t m i n e r a l f r a c t i o n , i t c o n t a i n s l e s s q u a r t z and more f e l s p a r t h a n t h e Wreck Bay m a r i n e e n v i r o n m e n t . T h e s e d i f f e r -e n c e s p e r h a p s r e f l e c t c o m p o s i t i o n a l v a r i a t i o n i n t h e " p a r e n t " c l i f f m a t e r i a l , o r e l s e a r e a r e s u l t o f t h e r e l a t i v e l y s m a l l amount o f c l i f f m a t e r i a l t h a t ha s b e e n e r o d e d f r o m Long B e a c h ( l o w c1 i f f p r o f i I e ) . Q u i s i t i s and Wya P o i n t s a m p l e s r e p r e s e n t d e p o s i t i o n by e x t r e m e l y h i g h w a v e - e n e r g y c o n d i t i o n s . T h e i r m i n e r a l o g i c c o m p o s i t i o n s a r e q u i t e s i m i l a r , and c o n t a i n low m a g n e t i t e and h i g h n o n - m a g n e t i c o p a q u e c o n c e n t r a t i o n s . An e x c e p t i o n t o t h e i r g e n e r a l u n i f o r m i t y o c c u r s w i t h t h e i r ( a u g i t e + d i o p s i d e ) / h o r n -b l e n d e r a t i o s ; f o r Q u i s i t i s P o i n t i t i s < l , and f o r Wya P o i n t i t i s > 3 . T h i s s u g g e s t s t h a t s e d i m e n t movement i s i n a s o u t h -e a s t d i r e c t i o n due t o i n c r e a s e d d i o p s i d e c o n c e n t r a t i o n a t Wya P o i n t , t h i s b e i n g t h e most r e s i s t a n t o f t h e t h r e e m i n e r a l s ( K r u m b e i n and P e t t i j o h n , 1 9 3 8 ) . An i n t e r e s t i n g p o i n t r e g a r d i n g T a b l e V I , i s t h e e x t r e m e v a r i a b i l i t y o f m a g n e t i t e , and a p p a r e n t u n i f o r m i t y o f n o n - m a g n e t i c o p a q u e m i n e r a l s i n t h e d i f f e r e n t s a m p l e s . T h i s may be a r e s u l t o f t h e p r e s e n t a t i o n , t h e f o r m e r b e i n g % by w e i g h t , and t h e l a t t e r % by c o u n t s , (b ) P r o v e n a n c e In g e n e r a l , s e d i m e n t s c o m p o s i n g t h e g l a c i o f l u v i a l o u t w a s h and g r e y c l a y a r e w e l l r e f l e c t e d by r o c k s e x p o s e d kl. i n l a n d f r om Wreck B a y . Ea s twood ( 1 9 6 8 ) has d e s c r i b e d s e v e n m a g n e t i t e o c c u r r e n c e s i n t h e a r e a , o n e o f w h i c h was m i n e d u n t i l r e c e n t l y by B r y n n o r M i n e s . No doub t t h e s e d e p o s i t s were i n s t r u m e n t a l i n p r o v i d i n g t h e m a g n e t i t e and o t h e r i r o n - o x i d e s now c o n t a i n e d i n t h e o u t w a s h . G a r n e t , d i o p s i d e and e p i d o t e p r o b a b l y came f rom t h e many s k a r n z o n e s i n t h e a r e a . T h e s e z o n e s have f o r m e d where a r g i l l i t e o f t h e Q u a t s i n o G roup and a n d e s i t e s o f t h e B o n a n z a Group l i e i n c o n t a c t w i t h t h e B a t h o l i t h i c I n t r u s i o n s . The l a t t e r c o n t a i n s r o u g h l y e q u i v a l e n t amounts o f q u a r t z and f e l s p a r , and o t h e r common m i n e r a l s i n -c l u d e h o r n b l e n d e , b i o t i t e and s e c o n d a r y c h l o r i t e . The f e l s p a r s c o n s i s t o f o r t h o c l a s e g e n e r a l l y h i g h l y a l t e r e d t o a l l o p h a n e , and p l a g i o c l a s e somewhat a l t e r e d t o s e r i c i t e , c l i n o z o i s i t e and e p i d o t e ( / E a s t w o o d , 1 9 6 8 ) . G r a v e l f o u n d on t h e b e a c h c a n u s u a l l y be c l a s s i f i e d p e t r o I o g i c a I Iy a c c o r d i n g t o p a r t i c l e s i z e and s h a p e . C o b b l e s a r e i n v a r i a b l y d i o r i t i c i n c o m p o s i t i o n , e l l i p s o i d a l i n s h a p e , and c o r r e I a t e a b I e w i t h t h e Kennedy B a t h o l i t h . C o a r s e p e b b l e s a r e g e n e r a l l y d i s c o i d a l t o e l l i p s o i d a l i n s h a p e , and commonly c o n s i s t o f p o r p h y r i t i c and a m y g d a l o i d a l b a s i c v o l c a n i c s , c h a l c e d o n y and j a s p e r , most l i k e l y d e r i v e d f r om t h e K a r m u t s e n G r o u p . F i n e p e b b l e s and g r a n u l e s a r e u s u a l l y i r r e g u l a r t o s p h e r o i d a l i n s h a p e , and c o n s i s t o f v e i n q u a r t z and some v o l -c a n i c s , b u t m o s t l y g r e y i s h - b r o w n i n d u r a t e d s e d i m e n t , w h i c h c a n be c o r r e l a t e d w i t h t h e Q u a t s i n o G r o u p and T o f i n o G r e y w a c k e U n i t . 48. Poi n t - c o u n t A n a 1 y s ! s X - r a y Di f f r a c t i o n Ana l y s i s Env i ronment L S C - 6 LOST SHOE CREEK ( F i g u r e 5) C - 1 C - 1 C-2 C-3 1 GREY CLAY C - 6 C - 2 C-3 C - 4 C-5 C-6 C - 7 • GLAC IOFLUV IAL OUTWASH . C L I F F (Map 1) C -2 C -2 BROWN CLAY BOULDER BOULDER BOULDER NWR-2a NWR-2D NWR-2c } } BERM FORESHORE . BEACH (Map 1 ) B - 19 BAY (Map 1 ) OS -4 SAND ^ OS-16 OS-I I OS- 12 OS- 13 OS- 14 OS-16 OS-17 OS-18 J MUD j . OFFSHORE (Map 2) L B - 4 LONG BEACH (Map 2) QP -4 QU IS IT I S POINT ( F i g u r e 5) WP- lb WYA POINT ( F i g u r e 5) r T a b l e V. S amp le s c o n s i d e r e d i n p o i n t - c o u n t and X - r a y d i f f r a c t i o n a n a l y s e s . Samp le l o c a t i o n s a r e i n d i c a t e d by r e f e r e n c e t o maps and f i g u r e s . 49. E n v i ronment Samp 1e % bv w e i a h t % bv c o u n t s Number Heavy M i n e r a l s T o t a l ! L i q h t Mi n e r a s T o t a l (62.5 - 125/0 s i z e f r a c t i o n i n s a m p l e MAGNETITE i n (62.5 - 125/0 s i z e f r a c t i o n NON-MAG. OPAQUES GARNET Zl RCON EPIDOTE + CLINOZO AUGITE + Dl OPS HBLD„ C H L O h l T E " QUARTZ CHERT K -FELS + PLAGIO, MUSCOV. + B l OTITE U LOST SHOE CHEEK L S C - 6 .04 5.17 8.4 .9 1,3 5.6 5.9 6.5 1,7 30.3 16.6 - 10.4 7?V 34.4 35,3 GKEY CLAY C - l 10.70 .84 5.0 .9 . 1 2.7 2.7 7,2 2.5 21,1 29,0 .3 14.4 3. 1 46.8 31.9 CLI FF< OUTWASH BKOWN CLAY C-6 C-2 3.75 13.40 5.47 .89 7.7 9.9 1.3 1.3 ..7 .9 4.4 3.1 4.2 3,7 8,6 8.4 2.0 2.4 28,9 29.7 20,2 19.2 2,9 1.3 13.8 19.3 5.0 3. 1 41,9 42.9 29.4 27.0 BOULDEK 16.85 - 7.2 .2 .2 1.6 .2 .2 2.7 12.3 14.0 - 11.7 5.4 31.1 56.6 NWR-2a .02 15.0 19,0 2.4 2.4 3.0 4.2 2.2 ,8 34.0 15.2 .4 6.8 1.8 24.2 41,8 B E A C H NWR-2b 4.22 .94 9.0 .3 1.9 2.8 3.6 4,7 1.6 23.9 24.8 .9 8.8 1.7 36.2 39.8 NWR-2c 8.75 2.85 8.3 1.8 1.4 3.2 3,4 5,2 2,8 26. 1 26,2 1.2 7. 1 ,8 35.3 38.7 BAY B- 19 12.02 2.22 7.8 .8 I.I 3.0 5.7 4.6 2. 1 25. 1 27.9 2. 1 7.4 2.8 40.2 35,0 OFFSHORE OS-4 OS- 16 21.22 15,10 10.49 1,6! 10.2 7.2 3.0 .6 .2 ,6 4.7 3.5 6.7 5.4 6,3 5,4 2,0 3,5 33. 1 26.2 23,8 29,4 1.0 2,3 6.9 5.6 1.2 2.7 32.9 40.0 33.5 34, 1 LONG BEACH LB-4 3.98 3.82 14.8 .5 I.I 4.1 6.9 5,5 4,9 37,8 15,9 .5 10.4 1.4 28.2 33.8 QUIS IT I S POINT QP-4 1 ,22 .67 1 1.2 - .7 3. 1 3.5 4,8 4,4 27,7 16,5 c9 7.9 1.8 26. 1 46.1 WYA POINT WP-lb 7.35 1 .91 15.3 . 1 . 1 4.2 6,2 2.0 2,8 30,7 1 17,6 .5 9. 1 1.5 28.7 40.7 Tab 1 e V I . P e t r o g r a p h y o f v e r y f i n e Sand f r o m F o u r t e e n R e l a t e d E n v i r o n m e n t s . U e q u a l s unknown M i n e r a l s , Rock F r a g m e n t s , and M i n e r a l S p e c i e s no t Cons i d e r e c L 5 0 . C. X-RAY D IFFRACTION ANALYSIS I . LABORATORY PROCEDURE C h e m i c a l p r e - t r e a t m e n t on 18 c l i f f and o f f s h o r e t r o u g h s a m p l e s i n v o l v e d t h e f o l l o w i n g ; C a r b o n a t e s and o t h e r s o l u b l e s a l t s were i n i t i a l l y removed by d i g e s t i n g i n NaOAc (pH = 5 . 0 ) . O x i d i z a b l e o r g a n i c m a t t e r was removed w i t h 30% H2®2 " E x t r a c t a b l e i r o n was i s o l a t e d f o r l a t e r a n a l y s i s , by b u f f e r i n g t h e s a m p l e s w i t h s o d i u m c i t r a t e , and s l o w l y a d d i n g s o d i u m d i t h i o n a t e D Two c l a y f r a c t i o n s (<0.2yu and 0 . 2 - 2 . 0 ^ ) , and two s i l t f r a c t i o n s ( 2 . 0 - 2 0 . 0 y u a n d 2 0 . 0 - 62.5/0 were i s o l a t e d f r o m e a c h s a m p l e , e x c e p t t h e c l i f f o u t w a s h s a m p l e s . The l a t t e r c o n t a i n e d l i t t l e f i n e m a t e r i a l , so t o t a l c l a y and t o t a l s i l t was i so I a t e d . The c l a y f r a c t i o n s were t h e n s p l i t i n two, o n e h a l f was K - s a t u r a t e d , and t h e o t h e r M g - s a t u r a t e d . A f t e r X - r a y i n g o r i e n t e d s l i d e s o f t h e s e m a t e r i a l s , t h e f o r m e r was h e a t e d t o 5 5 0 ° C , and t h e l a t t e r g l y c e r a t e d w i t h a 1:10 g I y c e r i n e : w a t e r s o l u t i o n , and b o t h were X - r a y e d a g a i n . S i l t s were s i m p l y mounted i n powder h o l d e r s and X - r a y e d o n c e . The p r o p o r t i o n o f c l a y , s i l t and v e r y f i n e s and i n e a c h s a m p l e was d e t e r m i n e d as f o l l o w s : V e r y f i n e s and was removed by s c r e e n i n g a known w e i g h t o f o r i g i n a l s a m p l e and d e t e r m i n i n g i t s w e i g h t p e r c e n t . M a g n e t i t e w e i g h t p e r c e n t a g e i n t h i s s i z e f r a c t i o n was a s c e r t a i n e d as d e s c r i b e d i n t h e 5 1 . p o i n t - c o u n t a n a l y s i s ( T a b l e V I I ) . 2 0 . 0 gms o f t h e m a t e r i a l <62.5yu.was s e p a r a t e d i n t o t h e v a r i o u s c l a y and s i l t f r a c t i o n s , and t h e s e were made up i n t o I l i t r e s u s p e n s i o n s . 5 0 . 0 ml o f t h e s e s u s p e n s i o n s were p i p e t t e d o u t i n t o w e i g h e d c r u c i b l e s , e v a p o r a t e d t o d r y n e s s , and w e i g h e d a g a i n . The w e i g h t p e r c e n -t a g e s were t h e n f o u n d by s i m p l e p r o p o r t i o n ( F i g u r e 6 ) . E x t r a c t a b l e i r o n was d e t e r m i n e d f r o m t h e l e c h a t e s o l u t i o n s o b t a i n e d d u r i n g c h e m i c a l p r e - t r e a t m e n t , on a P e r k i n E l m e r Mode l 303 A t o m i c A b s o r p t i o n S p e c t r o p h o t o m e t e r . The f r e e i r o n - o x i d e s i n c l u d e n o n - c r y s t a l l i n e c o a t i n g s on g r a i n s , and amorphous o x i d e s . V e r y l i t t l e i n t e r l a y e r i r o n o r c r y s t a l l i n e i r o n - o x i d e was i n c l u d e d i n t h e c h e m i c a l e x t r a c t i o n . The c o n -c e n t r a t i o n s were f o u n d i n p a r t s p e r m i l l i o n ( T a b l e V I I ) . T o t a l c a r b o n , w h i c h i n c l u d e s c a r b o n a t e , was d e t e r -m i n e d on a L e c o I n d u c t i o n F u r n a c e . Each s a m p l e was run t w i c e , and t h e a v e r a g e v a l u e s a r e e x p r e s s e d as w e i g h t p e r c e n t a g e s ( T a b l e V I I ) . 2. X-RAY ANALYSIS Cu r a d i a t i o n was u s e d f r om 3 - 3 0 d e g r e e s 20 a t 1 d e g r e e / m i n u t e f o r t h e c l a y s , and f r om 3 - 6 0 d e g r e e s 29 a t 2 d e g r e e s / m i n u t e f o r t h e s i l t s . The p r i n c i p a l c l a y m i n e r a l s and a m i x e d - l a y e r d e r i v a -t i v e were i d e n t i f i e d u s i n g t h e f o l l o w i n g c r i t e r i a : o l l l i t e - i n s e n s i t i v i t y o f i t s I OA peak t o a I I t r e a t m e n t s . Montmor i I l o n o i d (montmor i I I o n i t e + v e r m i c u l i t e ) - e x p a n s i o n 52 . o f i t s \k% peak t o 17 - 18$ on g l y c e r a t i o n , and c o l -l a p s e t o on h e a t i n g . V e r m i c u l i t e - p r e s e n c e o f a 12.2 - 12.6$ peak on t h e K-s a t u r a t e d , r o o m - t e m p e r a t u r e d i f f r a c t o g r a m . T h i s i s due •to p a r t i a l c o l l a p s e f rom l o s s o f i n t e r l a y e r w a t e r ( L a v k u l i c h , 1970, p e r s o n a l c o m m u n i c a t i o n ) . C h l o r i t e - i n s e n s i t i v i t y o f i t s IkA peak t o a l l t r e a t m e n t s . o K a o l i n i t e - c o l l a p s e o f i t s 7A peak on h e a t i n g . Montmor i I l o n o i d / c h l o r i t e m i x e d l a y e r - e x p a n s i o n t o 15.5 -on g l y c e r a t i o n , and c o l l a p s e t o I 1.0 - I 1.2A on h e a t i n g . K a o l i n i t e i s not e a s i l y d i s t i n g u i s h e d f r o m c h l o r i t e by X - r a y a n a l y s i s , as t h e l a t t e r p o s s e s s e s a s e c o n d - o r d e r b a s a l peak a t 7$ c o i n c i d e n t w i t h t h e k a o l i n i t e 7A p e a k . F o r t h i s i n -v e s t i g a t i o n , k a o l i n i t e p r e s e n c e was e s t a b l i s h e d b a s e d on t h e o d e g r e e o f 7A peak c o l l a p s e , when t h e K - s a t u r a t e d s l i d e was h e a t e d t o 5 5 0 ° C . S l i g h t c o l l a p s e was t a k e n as i n d i c a t i n g n e g l i g i b l e k a o l i n i t e , w h e r e a s c o m p l e t e c o l l a p s e i n d i c a t e d i t s p r e s e n c e . C o n f i r m a t o r y e v i d e n c e f o r t h e e x i s t e n c e o f k a o l i n i t e i n t h e g I a c i o f I u v i a I o u t w a s h was o b t a i n e d by B h o o j e d h u r ( 1 9 6 9 ) , who f o u n d i t i n a number o f s a m p l e s c o l l e c t e d f r o m a g r a v e l q u a r r y a t t h e T o f i n o - A I b e r n i - U c I u e I e t r o a d j u n c t i o n . S e m i - q u a n t i t a t i v e e v a l u a t i o n o f c l a y m i n e r a l p r o p o r -t i o n s was a c c o m p l i s h e d by c o m p a r i n g t h e f o u r d i f f r a c t o g r a m s o b t a i n e d by t h e d i f f e r e n t t r e a t m e n t s . No d e f i n i t e p e r c e n t a g e s 53. were c a l c u l a t e d m a i n l y because o f the d i v e r s i t y o f r e s u l t s o b t a i n e d from d i f f e r e n t t e c h n i q u e s ( P i e r c e and S i e g a l , 1969). A p r i o r i t y sy s tem d e v i s e d by L a v k u l i c h (1968) was employed i n -s t e a d ( T a b l e V I I ) . S i l t s were s i m p l y examined q u a l i t a t i v e l y f o r t h e i r m i n e r a l o g i c c o n t e n t . 3. RESULTS E x a m i n a t i o n o f c l i f f m a t e r i a l i n F i g u r e 6 i n d i c a t e s t h a t g l a c i o f l u v i a l outwash c o n t a i n s s m a l l , r ough l y equa l amounts o f c l a y and s i l t . Grey c l a y on t he o t h e r hand i s more v a r i a b l e i n t e x t u r e , b e i n g s i l t y i n samples C-2 and C - 3 , and c l a y - r i c h i n sample. C - I . T h i s i s p r o b a b l y a r e s u l t o f c o n t a -m i n a t i o n o f t h e fo rmer two samples by g I a c i o f I u v i a I outwash^ s i n c e t h i s m a t e r i a l o v e r l i e s the g rey c l a y i n t h e s e a r e a s , Compo s i t i ona I Iy, t he outwash i s a l s o more c o n s i s t e n t than t he g rey c l a y ( T a b l e V I I ) . I t s c l a y f r a c t i o n i s t y p i c a l l y c h l o r i t e -r i c h ( F i g u r e 7 ) , w i t h a f a i r amount o f i I l i t e and k a o l i n i t e ; t he s i l t f r a c t i o n (not shown) c o n s i s t s m a i n l y o f m i ca and a m p h i b o l e , w i t h l e s s e r q u a n t i t i e s o f m a g n e t i t e , e p i d o t e , d i o p s i d e and c h l o r i t e . C l a y i n the g rey c l a y i s a l s o p r e d o m i -n a n t l y c h l o r i t e i n samples C - l and C - 3 , but sample C-2 c o n -t a i n s r e l a t i v e l y more montmori I l o n o i d ; the s i l t f r a c t i o n c o n t a i n s m i ca and a l i t t l e m a g n e t i t e . As a g r oup , t he g rey c l a y and g I a c i o f I u v i a I outwash a r e bo th f a i r l y r i c h i n m i x e d - l a y e r m a t e r i a l , and c o n t a i n no v e r m i c u l i t e at a l l ; o f f s h o r e samples however, show e x a c t l y the o p p o s i t e r e l a t i o n s h i p . 54 . Brown c l a y c o n t a i n s more s i l t t h a n t h e g r e y c l a y a d j a c e n t t o i t ( F i g u r e 6 ) „ F u r t h e r m o r e , i t s c l a y f r a c t i o n has no montmor i I l o n o i d ( T a b l e V I I ) , t h e m a j o r component o f g r e y c l a y s a m p l e C - 2 a d j a c e n t t o i t ( F i g u r e 7K As i n d i c a t e d i n t h e p o i n t - c o u n t a n a l y s i s , i t s c o m p o s i t i o n c o r r e s p o n d s more c l o s e l y t o t h e o u t w a s h , t h a n i t doe s t o i t s p a r e n t m a t e r i a l . The b o u l d e r , a l t h o u g h s andy i n t e x t u r e , p o s s e s s e s r e l a t i v e l y more c l a y t h a n s i l t ( F i g u r e 6 ) . As was f o u n d f o r t h e v e r y f i n e s a n d , c l a y and p a r t i c u l a r l y s i l t f r a c t i o n s c o n -t a i n a b u n d a n t m i c a . The o f f s h o r e s a m p l e s a l l c o n t a i n a b o u t t w i c e as much s i l t as c l a y ( F i g u r e 6 ) . H o w e v e r , a d i s t i n c t t e x t u r a l t r e n d i n r e l a t i o n t o t h e i r g e o g r a p h i c l o c a t i o n s i s e v i d e n t . B o t h c l a y and s i l t p r o p o r t i o n s d e c r e a s e p r o g r e s s i v e l y f r o m s a m p l e 0 S - I 4 o u t i n t o t h e t r o u g h . T h i s s amp le came f r o m a b r o a d " s i l l " a r e a a t 50 f a t h o m s , and west f r o m h e r e , t h e t r o u g h a x i s d e e p e n s g r a d u a l l y t o 60 f a t h o m s a t s a m p l e l o c a t i o n OS-16 (Map 2 ) . The cI ay m i n e r a l o g y o f t h e s e s a m p l e s e x h i b i t t h e same t r e n d , 0 S - I 4 b e i n g c h l o r i t e - r i c h and m o n t m o r i I l o n o i d - p o o r , and s a m p l e s west f r o m h e r e b e c o m i n g p r o g r e s s i v e l y more montmor i I l o n o i d - r i c h and c h l o r i t e - p o o r ( F i g u r e 7 ) . O t h e r c l a y c o m p o n e n t s a r e l e s s s i g n i -f i c a n t , b u t s t i l l show t h e same t r e n d ( T a b l e V I I ) . The s i l t s a l l c o n t a i n g a r n e t , e p i d o t e and c a l c i t e , and i n a d d i t i o n , t h e more l a n d w a r d o n e s h a v e d i o p s i d e and t h e s e a w a r d o n e s have m i c a . 55; C l a y s r e p o r t e d a b o v e , and i n T a b l e V I I , a r e t h e c o a r s e f r a c t i o n s . F i n e c l a y s (<0„2 , u ) g e n e r a l l y showed some i n -c r e a s e i n t h e p r o p o r t i o n o f montmor i I l o n o i d o v e r c h l o r i t e , e x c e p t f o r t h e g i a c i o f I u v i a I o u t w a s h , w h i c h was a n a l y s e d f o r t o t a l c l a y . M a g n e t i t e i n t h e v e r y f i n e sand c h a r a c t e r i z e d t h e d i f f e r e n t e n v i r o n m e n t s v e r y w e l l ; g I a c i o f 1 u v i a I o u t w a s h i s r e l a t i v e l y r i c h i n m a g n e t i t e , g r e y c l a y i s i n t e r m e d i a t e , and t h e o f f s h o r e e n v i r o n m e n t i s p o o r i n m a g n e t i t e , , E x t r a c t a b l e i r o n and t o t a l c a r b o n show l e s s d i f f e r e n t i a t i o n , b u t i n a g e n e r a l way, c l i f f m a t e r i a l c o n t a i n s more o f t h e f o r m e r , and o f f s h o r e m a t e r i a l c o n t a i n s more o f t h e l a t t e r . F i n a l l y , q u a r t z and f e l s p a r c o n s t i t u t e t h e b u l k o f s i l t - s i z e d m a t e r i a l , t h e y a r e a l w a y s p r e s e n t i n c o a r s e c l a y s , and i n v a r i a b l y o c c u r i n f i n e c l a y s . T h i s i n d i c a t e s t h a t g l a c i a l r o c k f l o w e r has c o n t r i b u t e d s i g n i f i c a n t l y t o t h e com-p o s i t i o n o f t h e s e s i z e f r a c t i o n s . k. Pi SCUSSi ON C o n s i d e r i n g t h e d i s t r i b u t i o n o f c l a y and s i l t i n t h e o f f s h o r e t r o u g h , and a l s o t h e m i n e r a i o g i c s i m i l a r i t y b e t w e e n s a m p l e OS-14 and t h e c l i f f g I a c i o f I u v i a I o u t w a s h , l e a d s t o t h e s u g g e s t i o n t h a t t h e b r o a d " s i l l " a r e a i n t h e t r o u g h r e p r e s e n t s t h e l o c u s o f maximum f i n e s e d i m e n t d e p o s i t i o n a t t h e p r e s e n t t i m e . C l a y and s i l t m a t e r i a l e r o d e d f r o m t h e c l i f f i s i n i t i a l l y t r a n s p o r t e d s o u t h e a s t w a r d s by t h e n e a r s h o r e s u r f a c e c u r r e n t , and p r e s u m a b l y , i t s e t t l e s f r om s u s p e n s i o n i n t h e v i c i n i t y o f 56. the s i l l . A near-bottom c u r r e n t has been found by Gross et a l ( 1 9 6 9 ) , to move s l o w l y westwards a l o n g the t r o u g h towards i t s head, which would account f o r t h e d e c r e a s e i n c l a y and s i l t i n t h i s d i r e c t i o n . I t a l s o e x p l a i n s the i n c r e a s e o f the m o n t m o r i I l o n o i d / c h l o r i t e r a t i o i n a w e s t e r l y d i r e c t i o n , s i n c e montmori I l o n o i d p a r t i c l e s a r e s m a l l e r i n s i z e t o c h l o r i t e and remain i n s u s p e n s i o n longer ( L a v k u l i c h , 1968, p e r s o n a l commu<-ni c a t i o n ) . Other f a c t o r s s u p p o r t i n g the p r o p o s i t i o n t h a t the s i I I a r e a r e p r e s e n t s the locus o f maximum p r e s e n t - d a y sedimen-t a t i o n a r e : Of a l I the o f f s h o r e samples, OS-14 i s unique i n t h a t i t c o n t a i n s some m i x e d - l a y e r c l a y - a c h a r a c t e r i s t i c component o f the c l i f f m a t e r i a l ( T a b l e V I I ) . Samples OS-14 and OS-13 have the most t o t a l c arbon o f o f f -s h o re t r o u g h samples, s u g g e s t i n g i n t r o d u c t i o n o f c a r b o n a t e from sample OS-9 (Map 2 ) , which c o n t a i n e d 50% s h e l l - h a s h i n i t s c o m p o s i t i o n . A l t h o u g h k a o l i n i t e has been found i n a n c i e n t marine sediments ( G r i m , 1958), i t i s c h e m i c a l l y u n s t a b l e i n seawater due t o the a l k a l i n i t y (pH = 7.5 - 8.4) and h i g h c a t i o n concen-t r a t i o n ( Grim, 1968. D i a g e n e t i c a l t e r a t i o n o f t h i s c l a y m i n e r a l may account f o r i t s apparent d e c r e a s e i n the o f f s h o r e samples, and t h e c o r r e s p o n d i n g i n c r e a s e o f v e r m i c u l i t e and montmori I l o n o i d s ( T a b l e V I I ) . Other c o n t r i b u t i n g s o u r c e s o f 57. montmori I l ono id to the o f f s h o r e environment are the grey c l a y in the c l i f f , and p o s s i b l y the b a s a l t i c lava f low between the southeast c o r n e r o f Wreck Bay, and Pocket Beach. Brown c l a y in the c l i f f i s b e l i e v e d to o r i g i n a t e as a r e s u l t o f numerous h a i r - l i n e s y n e r i s i s c r ack s in the grey c l a y , which would be formed by a l t e r n a t e expans ion and c o l l a p s e o f i t s montmor i I l ono id c l a y component. M e t e o r i c water , o c c a -s i o n a l l y permeat ing through the o v e r l y i n g outwash g r a v e l s would produce these c r a c k s , and a l s o account f o r the h igh f r e e i r o n - o x i d e content o f the brown c l a y (15.6 ppm). A l t e r a t i o n has a p p a r e n t l y proceded i n t e r m i t t e n t l y as shown by dark c o n -c e n t r i c r i ng s o f abundant f r e e i r o n - o x i d e ( P l a t e 8b) . A number o f large c r a c k s extend ing s u b - p a r a l l e l to the c o n t a c t , have l o c a l l y r e s u l t e d in brown c l a y l y i n g s t r a t i g r a p h i c a I Iy below s e c t i o n s o f u n a l t e r e d grey c l a y ( P l a t e 8a) . C lay c o n t a i n e d in the bou lder i s very p o o r l y c r y s -t a l l i z e d as shown by low, broad d i f f r a c t o g r a m peaks, however, i t s c o h e s i v e p r o p e r t y was almost c e r t a i n l y r e s p o n s i b l e f o r b i n d i n g the u n i t t o ge the r when i t o r i g i n a l l y became i n c o r p o -ra ted i n t o the g I a c i o f 1uvia I outwash. Subsequent ly , a l t e r a t i o n o f magnet i te to f r e e i r o n - o x i d e has r e s u l t e d in i t s weakly cemented s t a t e . . D. GENERAL STRATIGRAPHY OF THE "PARENT" CLIFF  MATERIAL Grey c l a y in the c l i f f has been t e n t a t i v e l y c l a s s i -f i e d as g I a c i o I a c u s t r i n e in o r i g i n (Map I ) , due to the 58. p r e s e n c e o f i c e - r a f t e d p e b b l e s i n i t s c o m p o s i t i o n , and a l s o b e c a u s e o f t h e l i m i t e d a r e a l e x t e n t o f i t s e x p o s u r e . I t s low t o t a l c a r b o n c o n t e n t , and a p p a r e n t a b s e n c e o f s u l p h i d e s , i n -d i c a t e s low o r g a n i c p r o d u c t i v i t y i n an o x y g e n a t e d e n v i r o n -ment . G r i g g s and Kulm (1969) have d e s c r i b e d a p e b b l y c l a y d a t e d a t 3 7 , 0 0 0 y e a r s B . P . , on t h e s h e l f o f f t h e W a s h i n g t o n c o a s t , and A n d e r s o n (1968) has r e p o r t e d on a " d i a m i c t o n " p e b b l y c l a y f r o m t h e S t r a i t o f J u a n de F u c a o f 17 ,000 -2 1 , 0 0 0 y e a r s B .P . C o r r e l a t i o n o f t h e g r e y c l a y w i t h e i t h e r o f t h e s e u n i t s i s i m p o s s i b l e u n t i l i t s age i s d e t e r m i n e d by c '^ d a t i n g . P a t c h y o c c u r r e n c e s o f s i m i l a r m a t e r i a l h a v e b e e n f o u n d on t h e c o n t i n e n t a l s h e l f o f f V a n c o u v e r I s l a n d and i n B a r k l e y Sound ( B a r r , C a r t e r , 1970, p e r s o n a l c o m m u n i c a t i o n ) . B . E . B . Cameron o f t h e G e o l o g i c a l S u r v e y o f C a n a d a f o u n d t h a t f o r a m i n i f e r a c o n t a i n e d i n a s i n g l e s a m p l e f r o m B a r k l e y Sound ( C a r t e r , 1 9 7 0 ) , were m a r i n e s p e c i e s ; h o w e v e r , t h e " d i a m i c t o n " p e b b l y c l a y c o n t a i n e d f o r a m i n i f e r a r a n g i n g f r o m e s t u a r i n e s p e c i e s a t t h e b a s e , t o m a r i n e s p e c i e s n e a r t h e t o p ( A n d e r s o n , 1968) . The g r e y c l a y t h e r e f o r e has a l i m i t e d d i s t r i b u t i o n o v e r a p p a r e n t l y w i d e a r e a s , w h i c h s u g g e s t s t h a t i t was d e p o s i t e d i n i s o l a t e d d e p r e s s i o n s where c u r r e n t s were weak o r a b s e n t . The g I a c i o f I u v i a I o u t w a s h was p r o b a b l y d e p o s i t e d d u r i n g f i n a l r e t r e a t o f t h e V a s h o n i c e - s h e e t , 12,500 - 14,000 y e a r s B .P . C r o s s - b e d d i n g i n t h e c l i f f ( P l a t e 9 a ) i n d i c a t e s t h a t t h e m a t e r i a l was t r a n s p o r t e d f r o m t h e m o u n t a i n o u s h i n t e r -* See GLOSSARY 5 9 . l a n d n o r t h e a s t o f Wreck B a y , a c o n t e n t i o n s u p p o r t e d by t e x t u -raI v a r i a t i o n a t d i f f e r e n t l o c a t i o n s . Near t h e n o r t h end o f Long B e a c h i t i s e x p o s e d i n a r o a d q u a r r y as f i n e s a n d , a t Wreck Bay i t c o n s i s t s o f a p p r o x i m a t e l y 50% g r a v e l , and a t t h e n o r t h end o f Kennedy L a k e i t c o n s i s t s o f s u b - a n g u l a r b o u l d e r s and c o b b l e s w i t h r e l a t i v e l y l i t t l e m a t r i x . The mode o f d e p o s -i t i o n o f t h i s m a t e r i a l was p r o b a b l y q u i t e c o m p l e x , as e x h i b i t e d by an e x p o s u r e i n a q u a r r y j u s t n o r t o f U c l u e l e t . H e r e , c r o s s -b e d d e d g I a c i o f I u v i a I o u t w a s h i s o v e r l a i n i n p a r t by a wedge -s h a p e d sandy d e p o s i t o f p r o b a b l e m a r i n e o r i g i n , and t h i s i n t u r n i s c o v e r e d by a 3 f o o t l a y e r o f t i l l ( P l a t e 9 b ) . G r i g g s and Kulm ( I 9&9) h a v e i n d i c a t e d t h e maximum e x t e n t o f l a t e P l e i s t o c e n e g l a c i e r s as b e i n g a t t h e edge o f t h e c o n t i n e n t a l s h e l f o f f V a n c o u v e r I s l a n d . R e t r e a t o f t h e s e g l a c i e r s i n H o l o c e n e t i m e s , a c c o m p a n i e d by s e a l e v e l t r a n s g r e s -s i o n a c r o s s t h e c o n t i n e n t a l s h e l f , has r e s u l t e d i n t h e p r e s e n t d i s t r i b u t i o n o f r e c e n t s e d i m e n t s a l o n g t h e i n n e r s h e l f , and r e l i c t s e d i m e n t s o n bank s a l o n g t h e o u t e r s h e l f . As shown i n t h e p r e s e n t s t u d y , t h e c h a r a c t e r o f r e c e n t s e d i m e n t s i s w e l l e x p l a i n e d by t h e c o m p o s i t i o n o f t h e c l i f f m a t e r i a l , and by t h e o c e a n i c c u r r e n t s e x i s t e n t a t t h e p r e s e n t t i m e . 60. Envi ronment Sampie Number %_ by we J qht TOTAL CARBON % Coarse C 1 ay (0.2 - 2.0>L) IfrZ.b - I25A s i z e f r a c t i o r in sample F MAGNETlTE in i (62.5 - 125/0 s i z e f r a c t i o r tXTRACT-ABLE IRON , ( p . p . m . ) I LL IT E IMONTMOKI L L -ONOID VERMIC-ULITE CHLORITE KAOLINI TE MONTMORILL-ONOID/ CHLORIDE r < C - i , 10,70 .84 5.2 .6 JU /\ Pr ickick Pr * GREY C L A Y < 1 C-- 18, 10 ,66 4.0 .2 •JL> /V •kick Pr k-k Pr **• C-3 9,30 .75 4. -4 .6 * Pr k-kk •kit r C - 2 5,60 , 16 , 10.4 .5 •k Pr Pr kkk ** •k-k C-3 2.40 1 „ 03 6.1 . 1 Pr Pr *** * k-k CLI FF <J GLACIOFLUVIAL OUTWASH J C - 4 1.90 2,34 3.6 - ** Pr Pr kick ** •k C-5 2.65 3 = 58 . 4.2 - ** Pr Pr •kick ** k C-6 3.75 5.47 2.7 .1 ** Pr Pr kicks ** k C-7 3.00 3. I'8 3.8 1.6 ** Pr ickk ** Pr BROWN CLAY C-2 13.40 .89 15.6 . 1 ** Pr Pr *** BOULDER 16.85 - 9.4 .2 ** Pr Pr ** * OS- 1 i 66.00 .26 ; . 1.2 ,4 *** ** * Pr OS- I 2 51,40 . 19 2.7 it -ki; k* Pr OFFSHORE < MUD OS- 13 OS- 14 46 .CO 24.40 .46 ; •55 : | 3.9 4.8 1.3 •1.9 ** ** k-k Pr •k •ki-•kick kir-k Pr Pr Pr * OS- 16 15. 10 1.61 2.7 .7 ** k-k * Pr OS- 17 63 ,80 .27 2.5 .7 ** •k-k * Pr OS- 18 54.90 .36 2.7 .9 ** ** •kick Pr Pr | LEGEND ( L a v k u l i t c h , 1968): Pr = 0 - 10% ( p re sen t ) = ! I - 20% ( t r a c e ) = 2 1 - 40% (minor) = 4 1 - 60% (major) = 61 -100% ( d o m i n e n t ) k-k-k-k J a M e J / N ^ C o a r s e C l a y M i n e r a l o g y and o t h e r P r o p e r t i e s o f t h e C l i f f and O f f s h o r e T r o u g h E n v i r o n m e n t s . 61 brown clay mudball C2 -.. C1" S I ZE D ISTR IBUTION O F C L I F F & O F F S H O R E S A M P L E S fj CLAY QSILT GRAVEL + SAND : 5 0 o / c C3-C2'-.. OS10' OS11" of fshorg •6S17 OS15L ...-OS16 C4 OS12" "OS 18 C 5 C6-..- -OS 13 F I G U R E C7 OS 14 62 FIGURE 7 |C2 OUTWASH] X - r a y d i f f r a c t o g rams o f Mg-g I y c e r a t e d c o a r s e c l a y (0.2 -2.0/0. M = m o n t m o r i l l o n o i d , C = c h l o r i t e , I = i I l i t e , . K - C = k a o I i n i t e , c h l o r i t e , and Q - l = q u a r t z , i l l i t e . 6 3 . P l a t e 8 a . C o n t a c t b e t w e e n g r e y c l a y and o v e r l y i n g g l a c i o -f l u v i a l o u t w a s h . Brown c l a y o c c u r s b e t w e e n t h e s e h o r i z o n s , and a l s o a l o n g c r a c k s e x t e n d i n g i n t o t h e g r e y c l a y . No te g r a v e l f i l l e d s c o u r c h a n n e l i n t h e c l a y , and t r u n c a t e d c r o s s - b e d d i n g i n t h e g I a c i o f I u v i a I o u t w a s h . P l a t e 8 b . C l o s e - u p v i e w o f t h e c o n t a c t a r e a marked by i n s e t on P l a t e 8 a . C o n c e n t r i c a l t e r a t i o n r i n g s c a n be seen i n t h e brown c l a y . 6 4 . P l a t e 9 a . P o o r l y d e f i n e d c r o s s - b e d d i n g i n g I a c i o f I u v i a I o u t w a s h . C l i f f v i e w b e h i n d P r o f i l e D. PI a t e 9 b . G I a c i o f I u v i a I o u t w a s h , p a r t i a l l y o v e r l a i n by a wedge o f b e a c h ? s a n d , and c o v - r e d by 3 f e e t o f t i l l . E x p o s u r e i n r o a d - q u a r r y j u s t n o r t h o f U c l u e l e t . 65. V I . SED IMENT.S IZE ANALYSES A. INTRODUCTION G i a c i o f I u v i a 1 o u t w a s h and g r e y c l a y i n t h e c l i f f has been shown m i n e r a l o g i c a ; i y , t o have p r o v i d e d t h e m a t e r i a l f o r a l l o t h e r s e d i m e n t a r y e n v i r o n m e n t s i n t h e a r e a ( s e e h e a d i n g POINT COUNT A N A L Y S I S ) . A d e t a i l e d e x a m i n a t i o n o f t h e c l a y and s i l t c o m p o n e n t s i n t h e o f f s h o r e t r o u g h , l e d t o an u n d e r s t a n d i n g o f t h e i r d i s t r i b u t i o n i n t e rms o f known o c e a n i c c u r r e n t s ( s e e h e a d i n g on X-RAY D IFFRACTION A N A L Y S I S ) . The f i r s t p a r t o f t h e p r e s e n t i n v e s t i g a t i o n was u n d e r t a k e n t o d e t e r m i n e t h e r e g i o n a l p a t t e r n o f r e c e n t s e d i m e n t d i s p e r s a l e x c l u s i v e o f t h e c l a y / s i l t e n v i r o n m e n t o f t h e o f f -s h o r e t r o u g h , and g r e y c l a y i n t h e c l i f f „ T h i s was a c c o m -p l i s h e d by c h a r a c t e r i z i n g t h e t e x t u r a l p r o p e r t i e s o f t e n r e l a t -ed s e d i m e n t a r y e n v i r o n m e n t s i n t h e a r e a by means o f f r e q u e n c y d i s t r i b u t i o m c u r v e s , and t w o - d i m e n s i o n a l p a r a m e t e r p l o t s . The s e c o n d p a r t o f t h e i n v e s t i g a t i o n was c o n d u c t e d e n t i r e l y on t h e b e a c h e n v i r o n m e n t , t h e p r i n c i p a l s t u d y a r e a o f t h e t h e s i s . The p u r p o s e o f t h i s work was to d e t e r m i n e s e a s o n a l d i f f e r e n c e s i n t h e t e x t u r e o f s u r f i c i a l s e d i m e n t s on t h e b e a c h . T h i s was a c c o m p l i s h e d u s i n g two s e t s o f s a m p l e s ( s e e APPEND IX ) : L a r g e s a m p l e s ( a l s o u s e d i n t h e r e g i o n a l s t u d y ) were com-p a r e d u s i n g t h e i r s t a t i s t i c a l p a r a m e t e r s S m a l l s a m p l e s were c o m p a r e d u s i n g h i s t o g r a m s . 6 6 . B. METHODS I . SAMPLE COLLECT lON A t o t a l o f 123 l a r g e s a m p l e s were c o n s i d e r e d i n t h i s s t u d y . In a d d i t i o n t o t h e s e , 91 s m a l l s a m p l e s were c o l l e c t e d f r o m t h e p r o f i l e r o d s t a t i o n s on t h e b e a c h (See APPEND IX ) . 2. LABORATORY PROCEDURE A f t e r c o l l e c t i o n t h e s a m p l e s were l a i d o u t on c l e a n p a p e r t o d r y , so as t o a v o i d t h e f o r m a t i o n o f s a l i n e c r u s t s on t o p o f t h e s a m p l e b o x e s . Each s a m p l e was i n i t i a l l y p a s s e d t h r o u g h a T y l e r No .10 s i e v e (2 mm) t o s e p a r a t e t h e g r a v e l . T h i s g r a v e l f r a c -t i o n was t h e n s i e v e d t h r o u g h as many as e l e v e n s c r e e n s , t h e l a r g e s t h a v i n g a l\ i n c h mesh . The s a n d f r a c t i o n was r e d u c e d t o 100 gms on a m u l t i - r i f f l e s p l i t t e r , and t h e n s i e v e d f o r 10 m i n u t e s on a T y l e r R o - T a p s h a k e r . A s i e v e i n t e r v a l o f q u a r -t e r p h i was u s e d , w i t h s i e v e s r a n g i n g f r o m 1.6.8 mm ( - 0 . 7 5 0) t o 0 . 0 6 2 5 mm ( 4 . 0 0). O n l y o n e c l i f f s a m p l e had s i l t and c l a y s i z e m a t e r i -a l i n e x c e s s o f 1% o f t h e t o t a l s a m p l e w e i g h t . C o n s e q u e n t l y , a n a l y s i s o f t h i s m a t e r i a l was no t u n d e r t a k e n , and t h e s m a l l e r t h a n 4 . 0 0 f r a c t i o n was t r e a t e d as 6 .0 0 ( F r i e d m a n , 1967 ) . W e i g h i n g s t o t h e n e a r e s t 0.01 gm were done on a M e t t I e r B a I a n c e . 3. S T A T I S T I C A L PARAMETERS AND COMPUTER PROGRAM A p r o g r a m w r i t t e n by A . J . S i n c l a i r and J . W i l s o n was 67. u s e d on an IBr' c o m p u t e r , t o c a l c u l a t e t h e s e d i m e n t p a r a m e t e r s , b o t h g r a p h i c a l l y ( F o l k , 1968) and by t h e method o f moments ( P i e r c e and G o o d , 1966). Some o f t h e f o r m u l a e d e f i n e d by P i e r c e and Good (1966) d i f f e r f r om t h o s e o f F r i e d m a n (1961, 1967), and a r e : I k Mean X = - £ , f ( x ; ) x r . . ( I ) where n = t o t a l w e i g h t o f s a m p l e f ( x | ) = w e i g h t o f s i n g l e s i z e c l a s s x ; = m i d p o i n t o f same s i z e c l a s s i n 0 u n i t s k = t o t a l number o f s i z e c l a s s e s S t a n d a r d D e v i a t i o n s = ^ f ( x j ) ( x j - X ) 2 J•?• . . . . (2 ) k f ( x ? ) ( x j - * ) Skewness S k = 2"n £ 4 .....(3) Ku r t o s i s K u = -1 = 1 nsk ns k k f ( x . ) ( x . - X) y- i i In a d d i t i o n t o t h e s e p a r a m e t e r s , T r a s k ' s S o r t i n g C o e f f i c i e n t and p e r c e n t i l e s n e c c e s s a r y f o r d e t e r m i n i n g t h e g r a p h i c mea-s u r e s ( F o l k , 1968) were a l s o i n c l u d e d i n t h e c o m p u t e r p r i n t -o u t . F r e q u e n c e y d i s t r i b u t i o n c u r v e s f o r e a c h s a m p l e , and two -d i m e n s i o n a l p l o t s b e t w e e n v a r i o u s s t a t i s t i c a l p a r a m e t e r s were p r o d u c e d by a Ca l comp p l o t t e r c o n n e c t e d t o t h e c o m p u t e r . C. REGIONAL SEDIMENTARY PATTERN I. DERIVATION OF TYPE FREQUENCY CURVES The t e n e n v i r o n m e n t s c o n s i d e r e d i n t h i s s t u d y a r e 63. a r e l i s t e d i n T a b l e V I I I . A number o f s a m p l e s f r o m t h e s e e n -v i r o n m e n t s were r e j e c t e d ( T a b l e V I I I ) s i n c e t h e y c o n t a i n e d an e x c e s s o f 5% o f t h e t o t a l s amp le w e i g h t i n t h e f i r s t s i e v e f r a c t i o n ( c o a r s e g r a v e l ) , and t h e f r e q u e n c y c u r v e s were t h u s open e n d e d . Two s a m p l e s f r o m t h e Long Beach e n v i r o n m e n t were a l s o r e j e c t e d as o n e came c rom a c o a s t a l dune ( L B - 2 ) , and t h e o t h e r f r o m t h e mouth o f Sand H i l l C r e e k ( L B - 3 ) (Map 2 ) . The s t a t i s t i c a l p a r a m e t e r s and p e r c e n t a g e o f s i z e f r a c t i o n s l i s t e d i n T a b l e VI I I a r e t h e a r i t h m e t i c a v e r a g e s f o r e a c h e n v i r o n m e n t . As an i n d i c a t i o n o f t h e d i s p e r s i o n o f s a m p l e means a b o u t t h e a v e r a g e mean, t h e v a r i a n c e s o f e a c h e n v i r o n -ment were d e t e r m i n e d , and a r e shown a t t h e b o t t o m o f T a b l e V I I I . I t i s a p p a r e n t t h a t b e a c h ( b e r m , MHT, MWL), b a y , o f f -s h o r e and Long B e a c h e n v i r o n m e n t s a r e w e l l r e p r e s e n t e d by t h e a v e r a g e means , w h e r e a s g r a v e l - c o n t a i n i n g e n v i r o n m e n t s a r e much more v a r i a b l e i n mean s i z e . F r e q u e n c y c u r v e s i l l u s t r a t e d i n F i g u r e 8 were o b -t a i n e d f r om t h e Ca l comp p l o t s o f i n d i v i d u a l s a m p l e s . T h i s was done by c o m p a r i n g t h e a v e r a g e s t a t i s t i c a l p a r a m e t e r s o f an e n v i r o n m e n t ( T a b l e V I I I ) w i t h t h e s t a t i s t i c a l p a r a m e t e r s o f i n d i v i d u a l s a m p l e s w i t h i n t h a t e n v i r o n m e n t . The f r e q u e n c y c u r v e o f t h e b e s t - f i t t i n g s a m p l e was t h e n u s e d t o r e p r e s e n t t h e e n -v i r o n m e n t . E m p h a s i s i n s amp le s e l e c t i o n was b a s e d on t h e moment m e a s u r e s o f mean and s t a n d a r d d e v i a t i o n , and t h e s i z e -f r a c t i o n p e r c e n t a g e s . 69. 2. MODAL ANALYSIS C u r r a y ( I 9 6 0 ) f i r s t d e v e l o p e d t h i s t e c h n i q u e f o r t r a c i n g t h e g e o g r a p h i c d i s t r i b u t i o n o f s e d i m e n t mas se s i n t h e h i g h l y m i x e d r e c e n t sed i r r n t s o f t h e G u l f o f M e x i c o . E s s e n t i a l -l y h i s t h e s i s was t h a t i n d i v i d u a l no rma l c o m p o n e n t s i n p o l y -modal n o n - n o r m a l s e d i m e n t s , t e n d e d t o r e t a i n t h e i r own c h a r -a c t e r i s t i c s ( s t a t i s t i c a l p a r a m e t e r s ) . The p r e s e n t s t u d y d i f f e r s f r o m C u r r a y ' s ( I 9 6 0 ) i n t h a t t y p e f r e q u e n c y c u r v e s o f t e n known e n v i r o n m e n t s were c o m p a r e d f o r r e l a t e d modes , i n s t e a d o f i n d i v i d u a l s a m p l e f r e q u e n c y c u r v 3 s r e p r e s e n t i n g unknown e n v i r o n m e n t s . A s s u m i n g t h e s e t y p e c u r v e s ( F i g u r e 8) t o be t r u l y r e p r e s e n t a t i v e o f t h e t e n e n v i r o n m e n t s , a number o f d e d u c t i o n s on t h e r e g i o n a l s e d i m e n t a r y p a t t e r n c a n be made by modal c o m p a r i s o n s . The t y p e f r e q u e n c y c u r v e r e p r e s e n t i n g g I a c i o f I u v i a I o u t w a s h f r om t h e c l i f f i s c h a r a c t e r i z e d by f i v e p o o r l y d e f i n e d m o d e s , t h e p r i n c i p a l o n e b e i n g v e r y c o a r s e s and (0 t o - 1 . 0 0 ) . E x a m i n a t i o n o f i n d i v i d u a l s a m p l e f r e q u e n c y c u r v e s shows t h a t t h e p r i n c i p a l mode becomes p r o g r e s s i v e l y f i n e r s o u t h e a s t w a r d s f r om t h e t y p e s a m p l e l o c a t i o n C -2 (Map I ) , a n d a t C -7 i t o c c u r s a t 1.0 0 ( c o a r s e - medium s a n d ) . T h i s i s t h o u g h t t o r e f l e c t s a m p l i n g f r o m c o n s e c u t i v e l y h i g h e r s t r a t i g r a p h i c h o r i -z o n s w i t h i n t h e Wreck Bay F o r m a t i o n , and no t an i n d i c a t i o n o f t h e p a l e o - t r a n s p o r t d i r e c t i o n ( See APPEND IX ) . Not a l l s a m p l e s a r e c h a r a c t e r i z e d by t h e same f i v e modes , h o w e v e r , t h e s i z e 70. r a n g e o f s e d i m e n t f r o m a l l t h e s a m p l e s i s c o n s i s t e n t . The L o s t Shoe C r e e k e n v i r o n m e n t i s c h a r a c t e r i z e d by t h r e e p o o r l y d e f i n e d modes , t h e p r i n c i p a l o n e i n t h e medium sand r a n g e ( 1 .0 t o 2.0 0), and a l l o f them b e i n g c o r r e l a t a b l e w i t h t h e c o a r s e r c l i f f modes . The t h i r t e e n s a m p l e s f r om t h i s e n v i r o n m e n t a l l p o s s e s s e d t h e same p r i n c i p a l mode, b u t o n l y h a l f o f them had t h e g r a v e l mode ( -2.0 t o - 3 . 0 0). The r e l a -t i v e f i n e n e s s o f t h e p r i n c i p a l mode, i n d i c a t e s a p r e s e n t - d a y f l u v i a l t r a n s p o r t medium o f l e s s c o m p e t e n c y t h a n t h a t w h i c h t r a n s p o r t e d t h e g I a c i o f I u v i a I o u t w a s h . The s p a r s i t y o f f i n e s and o b s e r v e d i n t h e c r e e k bed and r e f l e c t e d i n t h e t y p e f r e q u e n c y c u r v e ( F i g u r e 8), t o g e t h e r w i t h t h e f a c t t h a t t h e c r e e k w a t e r d u r i n g t h e summer a p p e a r e d t o be f r e e o f s u s p e n d e d m a t e r i a l , i n d i c a t e s t h a t maximum c o m p e t e n c y e x p e r i e n c e d d u r i n g t h e s p r i n g thaw i s c a p a b l e o f t r a n s p o r t i n g a l l m a t e r i a l f i n e r t h a n 2 0 o u t o f t h e e n v i r o n m e n t . The b e a c h (berm) has a p r i n c i p a l mode i n t h e medium s and r a n g e ( 1 .0 t o 2.0 0) i d e n t i c a l t o t h a t o f L o s t Shoe C r e e k , and a m i n o r o n e c l o s e t o 2.0 0. The a b s e n c e o f modes c o a r s e r t h a n medium s and i n d i c a t e s t h a t t h i s m a t e r i a l i s u n -s t a b l e i n t h e e n v i r o n m e n t . The f o l l o w i n g model i s p r o p o s e d : The b e a c h c o n s i s t s o f a l t e r n a t i n g l a y e r s o f g r a v e l and sand ( P l a t e 2 3b ) , s u g g e s t i n g t h a t v i o l e n t w i n t e r s t o r m waves remove a l l s e d i m e n t a r y m a t e r i a l e x c e p t c o a r s e g r a v e l f r o m t h e b e a c h , w h i c h t h e n becomes c o n c e n t r a t e d as a l a g d e p o s i t . The backwash 71. f r om l e s s v i o l e n t s p r i n g s t o r m waves Is c a p a b l e o f r e m o v i n g f i n e s and a r d m a t e r i a l f i n e r t h a n t h i s f r om t h e b a c k s h o r e , and so a berm o f medium sand becomes e s t a b l i s h e d a b o v e t h e c o a r s e g r a v e l . As wave s i z e d e c r e a s e s e v e n f u r t h e r d u r i n g t h e summer, a n o t h e r berm i s b u i l t , t h i s t i m e o f f i n e s a n d , a l o n g t h e u p p e r f o r e s h o r e * So i n e f f e c t , t h e c o a r s e and h e a v y m a t e r i a l i s worked downward t h r o u g h t h e b e a c h s e c t i o n by a l t e r n a t i n g s e a -s o n a l wave c o n d i t i o n s . The s u g g e s t i o n o f a mode n e a r 2 0 a l -most c e r t a i n l y i n d i c a t e s r a p i d t r a n s f e r o f t h i s m a t e r i a l f r o m t h e c l i f f t o t h e f o r e s h o r e . From b e a c h (MHT) o u t t o t h e o f f s h o r e e n v i ronment s e d i m e n t s a r e a l l v e r y s i m i l a r , and c o r r e s p o n d t o t h e m i n o r modes b e t w e e n 1.0 and 2.0 0 a l r e a d y m e n t i o n e d i n t h e b e a c h (berm) and c l i f f e n v i r o n m e n t s . They do t e n d t o become s l i g h t l y f i n e r and more l e p t o k u r t i c f u r t h e r f r o m s h o r e , t h u s s u p p o r t -i n g t h e " c l a s s i c a l " c o n c e p t o f a s i z e - g r a d e d n e a r s h o r e modern s e d i m e n t p a t t e r n o f J o h n s o n ( 1 9 1 9 ) . T h e s e u n i m o d a l , v e r y w e l l s o r t e d s and s e x t e n d o v e r an e x t r e m e l y w i d e a r e a and c o n s i d -e r i n g t h e i n s i g n i f i c a n c e o f t h i s mode i n t h e t y p e f r e q u e n c y c u r v e o f t h e c l i f f ( and o t h e r c l i f f s amp le f r e q u e n c y c u r v e s ) , i t must e x i s t as a v e r y t h i n p r i s m on t o p o f t h e c o a r s e r s e d i -m e n t s . T h i s c o n t e n t i o n i s i n d i r e c t l y s u p p o r t e d by t h e " o u t c r o p " o f b o u l d e r bed s i n a r e a s a f f e c t e d by wave i n d u c e d c u r r e n t s ( s e e h e a d i n g WRECK BAY BATHYMETRY). The s m a l l r ange o f s t a n d a r d d e v i a t i o n s o f t h e s e e n v i r o n m e n t s ( T a b l e V I I I ) i n d i c a t e s t h a t 72. e x t r e m e l y u n i f o r m k i n e t i c e n e r g y c o n d i t i o n s p r e v a i l i n t h e s e h y d r o d y n a m i c r e g i o n s . An i n t e r e s t i n g p o i n t c o n c e r n i n g t h e o f f -s h o r e e n v i r o n m e n t i s a s m a l l mode o f v e r y f i n e s and ( 3 . 0 t o 4 . 0 0), T h i s s i z e f r a c t i o n c o n t a i n s most o f t h e h e a v y m i n e r a l s . The t y p e f r e q u e n c y c u r v e was o b t a i n e d f r o m s a m p l e OS-I ( F i g u r e 8), and t h i s same m i n o r mode e x i s t s i n s a m p l e s 0 S - 2 t o 0S-8 (Map 2 ) . Samp le 0 S - 4 was e x a m i n e d m i n e r a l o g i c a 1 Iy ( s e e h e a d -i n g POINT-COUNT A N A L Y S I S ) , and was f o u n d t o c o n t a i n an excep-t i o n a l l y h i g h h e a v y m i n e r a l c o n t e n t , s u g g e s t i n g t h e p r e s e n c e o f a r e l i c t b e a c h p l a c e r a t t h i s b a t h y m e t r i c l e v e l - a p p r o x i -m a t e l y 20 f a t h o m s ( s e e c h a p t e r on ECONOMIC GEOLOGY). The Long B e a c h e n v i r o n m e n t i s t y p i f i e d by a f r e q u e n c y c u r v e a l m o s t i d e n t i c a l t o t h e o f f s h o r e e n v i r o n m e n t . The c u r v e , d e r i v e d f r o m s a m p l e L B - 5 , a l s o r e f l e c t s a s m a l l mode b e t w e e n 3 .0 and 4 . 0 0, b u t t h i s i s u n i q u e t o s a m p l e L B - 5 . Samp le L B - 4 c o n t a i n e d a h i g h p r o p o r t i o n o f n o n - m a g n e t i c o p a q u e m i n e r a l s , b u t r e l a t i v e l y l i t t l e m a g n e t i t e ( s e e h e a d i n g POINT-COUNT A N A L Y S I S ) , t h u s s u g g e s t i n g t h a t no c o m p o s i t i o n a l r e l a t i o n s h i p b e t w e e n t h e two e n v i r o n m e n t s e x i s t s . Q u i s i t i s P o i n t has a p r i n c i p a l mode i n t h e c o a r s e t o v e r y c o a r s e s and r a n g e (-•'0 0), w h i c h has no c o r r e s p o n d e n c e t o o t h e r e n v i r o n m e n t s , and t h e r e f o r e p r o b a b l y r e p r e s e n t s m a t e r i a l d e r i v e d l o c a l l y f r o m wave d e s t r u c t i o n o f t h e h e a d l a n d . A v e r y m i n o r mode o f f i n e s and ( 2 . 0 t o 3 ,0 0) c o r r e s p o n d s to t h e Long B e a c h p r i n c i p a l mode b e c a u s e o f c l o s e p r o x i m i t y o f t h e 73. t y p e s a m p l e l o c a t i o n (QP-7) t o t h i s e n v i r o n m e n t ( F i g u r e 8 ) . O n l y s a m p l e r QP-1 and QP-2 p o s s e s s p r i n c i p a l modes c o r r e l a t a b l e w i t h t h e Wreck Bay b e a c h (berm) and b e a c h (MHT, MWL) e n v i r o n -m e n t s . Wya P o i n t i s c h a r a c t e r i z e d by a p r i n c i p a l mode o f medium s and ( 1 . 0 t o 2.0 0) w h i c h c o r r e s p o n d s t o t h e b e a c h (berm) e n v i r o n m e n t . Of t h e e l e v e n s a m p l e s c o l l e c t e d f r o m t h i s h e a d l a n d , o n l y t h r e e d i d no t p o s s e s s modes t y p i f i e d by t h e Wreck Bay s e d i m e n t s . T h e s e were WP-2 and WP-3, w h i c h came f r o m s m a l l p o c k e t b e a c h e s a t t h e h e a d o f n a r r o w g o r g e s , and WP-6, d e r i v e d f r o m a s a n d - f i l l e d r o c k d e p r e s s i o n on top o f t h e h e a d -l a n d . T h i s s u p p o r t s e a r l i e r i n d i c a t i o n s t h a t a s o u t h e a s t m o v i n g n e a r s h o r e c u r r e n t e x i s t s a l o n g t h i s p a r t o f t h e c o a s t ( s e e c h a p t e r on SEA CONDITIONS, and h e a d i n g on POINT-COUNT A N A L Y S I S ) . A m i n o r mode o f v e r y c o a r s e s and (0 t o - 1 . 0 0) p r o b a b l y r e f l e c t s l o c a l d e s t r u c t i o n o f t h e h e a d l a n d by h i g h -e n e r g y waves . 74. Normal t o c o a s t P a r a l l e i t o c o a s t • i LOST SHOE CREEK (LSC ) CLI FF GLAC1OFLUV1AL OUTWASH (C ) BEACH BERM 1 BEACH MHT BEACH MWL BAY (3) CFF:-;;3RE (CS) LONG BEACH (LB ) 0U I S I 7 I S POINT (CP) WYA POINT (WP) MEAN X .40 - 1 , 1 0 1.36 2.45 2 .60 2,71 2.84 2.72 , 06 1.18 MOMENTS STD.DEV. s SKEWNESS S. k 1.30 - .21 1.96 0.7 .71 - . 5 4 . 6 9 - 2 .21 .56 - 2 . 4 6 .44 - 2 . 3 8 . 3 4 - L 3 7 .25 " l o l l 1.21 ,26 . 6 7 - . 6 9 KURTOSIS K u .94 - . 0 6 2 .89 2 1 . 6 9 2 0 . 8 3 2 3 . 9 8 22, 19 ! 0 , 24 1. 1 i 2 .96 MEAN M z .47 - 1 . 1 2 1.39 2.51 2 .69 2.75 2,85 2.73 .01 1.20 GRAPHIC STD.DEV, CT SKEWNESS Sk 1 1.24 - . 1 3 1.95 - . 0 2 .65 - . 0 9 .50 - . 1 9 . 3 0 - . 19 .29 - . 19 , 2 7 .01 .22 14 1.16 .06 .62 , 1 8 KURTOSIS K_ G 1.08 . 9 0 1. 1 1 1.26 1,55 1.63 1.51 1.03 1. 17 h 17 TKASK SORTING COEFF. (mm) So 2. 18 2 .70 1.34 1. 13 ! . 12 1.13 1. 10 1. 1 1 " 1.99 1.39 MODE (0) Mo .05 - 2 , 4 2 1.52 2 .78 2.80 2.97 3.00 2,92 - . 14 1.23 MEDIAN (0) .64 - 1 . 8 2 1 .42 2.67 2.70 2.78 2,85 2,75 .25 1.25 g r a v e 1 18,08 51.31 .81 3 s 33 .65 1 .61 „ 1 1 - 2 3 . 9 8 8.31 7 Sand 81.81 4 8 . 13 9 9 . 19 96.67 9 9 . 3 5 9 9 . 3 6 9 9 - 8 2 9 9 , 9 8 , 7 6 , 0 0 9 1 . 6 9 S i It 5- C 1 ay . 1 1 .56 - - -c 0 3 - 0 7 ,02 , ..02 -Number o f s a m p l e s c o 1 1 e c t e d 13 6 14 14 14 25 13 5 8 1 1 Samp 1es no t 1 n c l u -ded i n a v e r a g e s LSC -3 C - 4 C - 7 NWR-2 SER-5 SER-7 B- 1 B-3 B-8 B- 18 B-23 OS-7 OS-9 OS- 10 OS- 15 OS- 19 OS -20 L B - 2 L B - 3 QP-3 V a r i a n c e o f means (x^) .81 .42 .21 .33 .01 .01 0 0 .42 .48 i ab I e V I M » A v e r a g e S t a t i s t i lea! P a r a m e t e r s o f Type S e d i m e n t f r o m Ten R e l a t e d E n v i r o n m e n t s . 75 FIGURE 8 FREQUENCY CURVES OF TYPE SEDIMENTS FROM TEN RELATED ENVIRONMENTS COLUMN 1 COLUMN 2 NE/SW NW/SE n o r m a l t o c o a s t p a r a l l e l t o c o a s t 300-1 200-150-U 100 75 50 -25-0 -v e r t i c a l s c a l e z UJ O COLUMN 1 - 2 - 1 0 1 2 COLUMN 2 76. 3. TWO-DIMENSIONAL PARAMETER PLOTS (a ) Moment M e a s u r e s v s „ G r a p h i c a l M e t h o d s F o r many y e a r s g e o l o g i s t s have a t t e m p t e d t o d i s t i n g u i s h b e t w e e n d i f f e r e n t s e d i m e n t a r y e n v i r o n m e n t s by means o f b i v a r i a t e p l o t s . . W i t h t h e r e c e n t i n c r e a s e d a v a i l a b i -l i t y o f c o m p u t e r s , many w o r k e r s ( K o l d i j k , 1967; C h a p p e l l , 1967; F r i e d m a n , 1961, 1967; G r e e n w o o d , 1969) have e x p r e s s e d a p r e f e r e n c e f o r moment m e a s u r e s o v e r g r a p h i c a l p r o c e d u r e s f o r d e t e r m i n g t h e g r a i n - s i z e p a r a m e t e r s . Moment m e a s u r e s r e q u i r e l e n g t h y c a l c u l a t i o n s , b u t c o n s i d e r t h e e n t i r e f r e q u e n c y d i s -t r i b u t i o n ; g r a p h i c a l methods i n v o l v e l e s s t e d i u m , bu t c o n -s i d e r o n l y a few s p e c i f i c p o i n t s on t h e c u m u l a t i v e c u r v e . F o l k (1966) has h i g h l i g h t e d some o f t h e d i s a d v a n t a g e s o f moment m e a s u r e s , b u t a d m i t s t h a t i t i s " t h e most e l e g a n t m a t h e m a t i c a l method f o r o b t a i n i n g p a r a m e t e r s " . R e f e r r i n g t o T a b l e V I I I , mean and s t a n d a r d d e v i a -t i o n v a l u e s o b t a i n e d by b o t h p r o c e d u r e s a r e q u i t e s i m i l a r . Skewness and e s p e c i a l l y k u r t o s i s v a l u e s t h o u g h , d i f f e r w i d e l y . I t i s g e n e r a l l y a g r e e d ( F r i e d m a n , 1961, 19^7; F o l k , 1968) t h a t b e a c h s and s a r e n e g a t i v e l y skewed b e c a u s e f i n e m a t e r i a l i s w innowed f rom t h e i r d i s t r i b u t i o n s by t h e swash and b a c k w a s h . T h i s c h a r a c t e r i s t i c i s i l l u s t r a t e d by t h e moment skewness v a l u e s f o r b e a c h (MHT, MWL), b a y , o f f s h o r e and Long B e a c h e n -v i r o n m e n t s . In c o n t r a s t , t h e g r a p h i c p r o c e d u r e i n d i c a t e s a l -most e q u i v a l e n t n e g a t i v e s kewnes s f o r L o s t Shoe C r e e k and 77 . Long B e a c h e n v i r o n m e n t s . F o r k u r t o s i s , t h e g r a p h i c method a p p e a r s t o be e v e n more e r r o n e o u s , s i n c e t h e L o s t Shoe C r e e k e n v i r o n m e n t i s i n d i c a t e d as b e i n g more l e p t o k u r t i c t h a n Long B e a c h . On t h e s t r e n g t h o f t h e s e a r g u m e n t s , a l l t w o - d i m e n -s i o n a l p l o t s were c o n s t r u c t e d f r o m s t a t i s t i c a l p a r a m e t e r s d e t e r m i n e d by t h e method o f moments. (b) E n v i r o n m e n t D i s c r i m i n a t i o n by T w o - d i m e n s i o n a l  P l o t s A l l t h e e n v i r o n m e n t s c o n s i d e r e d i n t h i s s t u d y i n -v o l v e s e d i m e n t d e p o s i t e d by w a t e r , and f u r t h e r m o r e , t h e s i z e -r ange o f s e d i m e n t i n some o f t h e s e e n v i r o n m e n t s i s v e r y l a r g e . G e o l o g i s t s c o n c e r n e d w i t h t h i s t y p e o f a n a l y s i s have u s u a l l y c o m p a r e d m a t e r i a l f r o m d i f f e r e n t d e p o s i t i o n a l e n v i r o n m e n t s e . g . w ind b l o w n d u n e s , r i v e r d e p o s i t e d s a n d s , e t c . , and t h e m a t e -r i a l u s e d g e n e r a l l y f a l l s w i t h i n a v e r y n a r r o w s i z e - r a n g e e . g . f i n e s and o r medium s a n d , e t c . T h i s p a r t i a l l y a c c o u n t s f o r t h e g r e a t v a r i a b i l i t y o f e n v i r o n m e n t a l d i v i d i n g l i n e s o b t a i n e d by d i f f e r e n t w o r k e r s , f o r p l o t s o f t h e same p a r a m e t e r s . T h e r e i s w i t h o u t d o u b t a c e r t a i n amount o f i n t e n t i o n a l b i a s on t h e p a r t o f some w o r k e r s t h o u g h , as many o f t h e d i v i - l i n g l i n e s a r e drawn i r r e g u l a r l y t o i n c l u d e o r e x c l u d e s a m p l e s f r o m a p a r t i c u -l a r e n v i r o n m e n t a t w i l l . F o r e x a m p l e , a commonly u s e d p l o t i s mean v s . s t a n d a r d d e v i a t i o n . F i g u r e 9 i s a p l o t o f t h e s e p a r a -m e t e r s , and t h e t i g h t c l u s t e r o f p o i n t s shown i n t h e b l o w n - u p i n s e t r e p r e s e n t s b e a c h (MHT, MWL), b a y , o f f s h o r e and Long B e a c h 78, e n v i r o n m e n t s . T h i s a r e a c o r r e s p o n d s t o a dune e n v i r o n m e n t o f F r i e d m a n (1961), c o a s t a l dune o r r i v e r e n v i r o n m e n t s o f M o i o l a and W e i s e r ( 1 9 6 8 ) , . b a r r i e r dune e n v i r o n m e n t o f H a i l s and Hoyt (1969), and t o o n l y o n e b e a c h e n v i r o n m e n t , t h a t o f F r i e d m a n (1967). T h i s means t h a t w a t e r - l a i d d e p o s i t s c a n n o t s i m p l y be d i f f e r e n t i a t e d u n i v e r s a l l y f r om o t h e r e n v i r o n m e n t s by a mean v s . s t a n d a r d d e v i a t i o n p l o t , b e c a u s e o f t h e g r e a t r ange o f s e d i m e n t s i z e s p o s s i b l e a t d i f f e r e n t l o c a t i o n s . F o u r o f t h e most common t w o - d i m e n s i o n a l p l o t s have b e e n c o n s t r u c t e d t o p o r t r a y t h e r a n g e o f i n d i v i d u a l s a m p l e p a r a m e t e r s , and t o a s s e s s t h e i r m e r i t i n d e f i n i n g t h e t e n e n -v i r o n m e n t s s e l e c t e d f o r s t u d y a t Wreck Bay ( F i g u r e s 9, 10, I I , 12). ( i ) Mean v s . s t a n d a r d d e v i a t i o n T h i s p l o t ( F i g u r e 9) i s s u p e r i o r t o t h e o t h e r s . The t i g h t c l u s t e r o f p o i n t s r e p r e s e n t i n g b e a c h (MHT, MWL), b a y , o f f s h o r e and Long B e a c h e n v i r o n m e n t s a r e a l l u n i m o d a l l e p t o k u r t i c s e d i m e n t s ( F i g u r e 8), y e t e x a m i n a t i o n o f t h e b l o w n -up i n s e t ( F i g u r e 9) r e v e a l s t h a t e n v i r o n m e n t d i s c r i m i n a t i o n , a l t h o u g h v a g u e , i s s t i l l p o s s i b l e . G I a c i o f I u v i a I o u t w a s h p o i n t s f a l l w i t h i n a r e l a t i v e l y s m a l l a r e a a t t h e o p p o s i t e c o r -n e r o f t h e d i a g r a m . In b e t w e e n t h e s e two a r e a s , t h e t r a n s i t i o -na l e n v i r o n m e n t s o f L o s t Shoe C r e e k and b e a c h (berm) o c c u r . The f o r m e r s a m p l e s a r e s p r e a d o v e r t h e e n t i r e r ange o f p a r a -m e t e r v a l u e s ( s e e h i g h v a r i a n c e o f means - T a b l e V I M ) , 79. w h e r e a s t h e l a t t e r a l m o s t a l l f a l l i n t h e m o d e r a t e l y w e l l s o r t e d , medium sand b r a c k e t . In c l o s e a s s o c i a t i o n w i t h t h e s e b e a c h (berm) p o i n t s a r e t h o s e o f Wya P o i n t , t h u s i n d i r e c t l y c o n -f i r m i n g t h e e x i s t e n c e o f a s o u t h e a s t m o v i n g n e a r s h o r e c u r r e n t . Q u i s i t i s P o i n t on t h e o t h e r h a n d , showed a w i d e r ange o f p a r a -m e t e r v a l u e s . I t i s a p p a r e n t t h a t e n v i r o n m e n t d i s c r i m i n a t i o n i s l a r g e l y d e t e r m i n e d by t h e mean g r a i n s i z e , and t h a t a weak c o r r e l a t i o n e x i s t s b e t w e e n t h e two p a r a m e t e r s v i z . a n i n c r e a s e i n g r a i n s i z e g e n e r a l l y r e f l e c t s a d e c r e a s e i n s o r t i n g . A s t r a i g h t d i v i d i n g l i n e drawn a l o n g mean 2.0 0 w o u l d s u c c e s s -f u l l y i s o l a t e t h e u n i m o d a l l e p t o k u r t i c s e d i m e n t s f r o m t h e o t h e r s , b u t t h i s l i n e w o u l d f a l l more o r l e s s a t r i g h t a n g l e s t o t h o s e f o u n d by o t h e r w o r k e r s . The r e a s o n f o r t h i s i s u n -d o u b t e d l y due t o t h e much w i d e r s e d i m e n t r a n g e u s e d h e r e by c o m p a r i s o n t o t h e s e d i m e n t u s e d by o t h e r w o r k e r s . ( i i ) Mean v s . Skewness Skewness has b e e n f o u n d by most g e o l o g i s t s ( F r i e d m a n , 1961; H a i l s , 1967; K o l d i j k , 1968, G r e e n w o o d , 1969) t o be t h e most s e n s i t i v e e n v i r o n m e n t a l i n d i c a t o r . The s i g n o f s kewnes s d e p e n d s w h o l l y on t h e t a i l s o f a f r e q u e n c y d i s t r i b u -t i o n c u r v e , and h e n c e b e a c h s e d i m e n t s a r e n e g a t i v e l y skewed ( l a c k o f f i n e t a i l ) ; i n l a n d w i n d - b o r n e s a n d s a r e p o s i t i v e l y skewed ( l a c k o f c o a r s e t a i l ) ; and r i v e r s e d i m e n t s h a v e c l o s e t o z e r o skewnes s ( p r e s e n c e o f c o a r s e and f i n e t a i l s ) . M o i o l a and W e i s e r (1968) h a v e , h o w e v e r , f o u n d t h a t c o a s t a l w i n d - b o r n e dunes p o s s e s s n e g a t i v e skewness a p p r o x i m a t e l y 50% o f t h e t i m e due to f i n e m a t e r i a ! remova l i n s u s p e n s i o n , and m i g r a t i o n o f t h e b a l a n c e by s a l t a t i o n . S amp le L B - 2 , t h e o n l y o n e f r o m a c o a s t a l d u n e , does i n f a c t p o s s e s s n e g a t i v e skewnes s ( F i g u r e 10) . Skewness r ange o f t h e u n i m o d a l l e p t o k u r t i c s e d i m e n t s i s much g r e a t e r t h a n t h e i r s t a n d a r d d e v i a t i o n s , and h e n c e t h e s e p o i n t s f a l l o v e r a w i d e r a r e a t h a n i n F i g u r e 9. I t i s t h e mean, and not s k e w n e s s , w h ? c h a g a i n i s most e f f e c t i v e i n d i s c r i m i n a t -i n g b e t w e e n t h e s e w a t e r - d e p o s i t e d e n v i r o n m e n t s . A s t r a i g h t l i n e drawn a t mean 2.0 0 w o u l d l i k e w i s e s e p a r a t e t h e u n i m o d a l l e p t o k u r t i c s e d i m e n t s f r o m t h e o t h e r s . A weak p a r a m e t e r c o r r e -l a t i o n i s a l s o e v i d e n t w i t h t h i s p l o t v i z . a n i n c r e a s e i n g r a i n s i z e i s u s u a l l y a c c o m p a n i e d by a more p o s i t i v e s k e w n e s s . ( i i i ) S t a n d a r d d e v i a t i o n v s . Skewness F r i e d m a n (1961) o b t a i n e d an e n v i r o n m e n t a l d i v i d i n g l i n e , w h i c h on t h e s c a l e o f F i g u r e II i s a l m o s t s t r a i g h t , and e x t e n d s a p p r o x i m a t e l y a l o n g t h e m i d d l e o f t h e w e l l s o r t e d c a t a g o r y . T h i s l i n e s e p a r a t e d a b e a c h e n v i r o n m e n t ( b e l o w ) f r o m a r i v e r e n v i r o n m e n t ( a b o v e ) , and i n t h e c a s e o f F i g u r e I I, w o u l d s e p a r a t e t h e u n i m o d a l l e p t o k u r t i c s e d i m e n t s ( b e l o w ) f r o m t h e o t h e r s . F u r t h e r d i s t i n c t i o n b e t w e e n t h e u n i -modal l e p t o k u r t i c e n v i r o n m e n t s t h o u g h , i s not p o s s i b l e . In t h i s p l o t , s t a n d a r d d e v i a t i o n i s more e f f e c t i v e 8 1 . t h a n skewnes s i n d i s c r i m i n a t i n g be tween t h e w a t e r - d e p o s i t e d e n v i r o n m e n t s . C o r r e l a t i o n be tween t h e two p a r a m e t e r s i s a p p a r e n t l y v e r y weak, ( i v ) Skewness vs., K u r t o s i s T h i s p l o t ( F i g u r e 12) i s t h e l e a s t e f f e c t i v e i n d i s c r i m i n a t i n g b e t w e e n t h e e n v i r o n m e n t s . I t w i l l be n o t i c e d t h a t a number o f s a m p l e s a r e i n d i c a t e d as h a v i n g n e g a t i v e k u r t o s i s , w h i c h i n f a c t i s p h y s i c a l l y i m p o s s i b l e . T h i s i s due t o t h e f o r m u l a s u p p l i e d by P i e r c e and Good ( 1 9 6 6 ) , i n w h i c h t h e y s u b t r a c t 1.5 f r o m t h e d e t e r m i n e d v a l u e . A f a i r l y good c o r r e l a t i o n b e t w e e n t h e two p a r a m e t e r s i s e v i d e n t t h o u g h , v i z , i n c r e a s e d n e g a t i v e skewnes s i s g e n e r a l l y a c c o m p a n i e d by i n -c r e a s e d k u r t o s i s . h. CONCLUSIONS The method e m p l o y e d i n modal a n a l y s i s , a l t h o u g h a p p r o x i m a t e , a l l o w e d e n v i r o n m e n t c h a r a c t e r i z a t i o n and j u d g m e n t on t h e d i s t r i b u t i o n o f n e a r s h o r e r e c e n t s e d i m e n t s . B i v a r i a t e a n a l y s i s was o n l y p a r t i a l l y e f f e c t i v e i n e n v i r o n m e n t d i s c r i m i -n a t i o n , bu t d i d i l l u s t r a t e t h e r a n g e o f s e d i m e n t p a r a m e t e r s c o n t a i n e d by any o n e e n v i r o n m e n t . The p l o t o f mean v s , s t a n -d a r d d e v i a t i o n was t h e most e f f e c t i v e i n d i s t i n g u i s h i n g b e t w e e n t h e d i f f e r e n t w a t e r - d e p o s i t e d e n v i r o n m e n t s . Moment m e a s u r e s o f s kewnes s and k u r t o s i s were t h e l e a s t e f f c i e n t p a r a m e t e r s . S i n c e mean and s t a n d a r d d e v i a t i o n v a l u e s f o u n d by moment and g r a p h i c p r o c e d u r e s a r e i n s u c h c l o s e a g r e e m e n t , v a l u e s d e r i v e d by t h e l a t t e r method may h a v e been e m p l o y e d w i t h e q u a l m e r i t . 82 O CM CM' O vary w e l l s o r t e d we l l s o r t e d 1 i _ moderate ly s o r t e d r: c - ro *- It K>LB3. p o o r l y s o r t e d v e r y w e l l s o r t e d w e l l s o r t e d v e r y •poo r l y I f s o r t e d • • • x •1 + A A • A A 0 3 S T D . DEV. i — 0-4 0-5 CM 6 2 < LU 2 12 ro o-o " c re > O T cp. T M E A N vs. S T A N D A R D DEV IAT ION ( M O M E N T S ) ID CM I eV i N O R M A L T O C O A S T L I N E P A R A L L E L TO C O A S T L I N E o L o s t S h o e C r e e k O L o n g B e a c h • C l i f f A Quis i t is Point « Berrr)") * , B e r m + M . K T . S B e a c h a Wya Point * M.W.L.J • B a y a O f f s h o r e CM —r— 0-5 — i 075 —I— 1 0 o-o •-F I G U R E 9 — i — 20 0-25 STD. DEV. 1-25 — i — 15 -T 175 83 * 1 1 1 i i c c ns w E g I xi (9 E X ^ 3 r B2 A • * * AJ I xi c ffl o u A -FIGURE TO MEAN vs. SKEWNESS (MOMENTS) rn u c ffl c > •4 > O l NORMAL TO COASTLINE PARALLEL TO COASTLINE o Lost Shoe Creek O Long Beach • Cliff A Quisitis Point * Berml * Berm + M . H . T A Beach a Wya Point x MW.L.J • Bay Q Offshore - 1 — -10 — I — -05 -30 I— -2-5 —i 1— -20 -1-5 SKEWNESS 0 0 84 o l _ o o a > •a o I/) S T A N D A R D DEV IAT ION VS. S K E W N E S S (MOMENTS) NORMAL TO COASTLINE PARALLEL TO COASTl INF o Lost Shoe Creek O Long Beach • Cliff A Quisitis Point * Berm ,| * Berm + M.H.T.l Beach A Wya Point * M. W.L.J • Bay Q Offshore FIGURE 11 o L o o a o I >• m c o E —+ . "o >>« x *>r! m o t - 10 •o o E •o X — w 1 • J o X a J 1 A ••A 4. * " + + * • • • o • + A Tf A OLB2 A * o A--0LB3 -30 -2-5 —I i " 2 ' ° S K E W N E S S " 1 ' 5 -10 1 — -05 00 %0 \ a • * X X X 8 5 -• « 1 I S K E W N E S S VS. K U R T O S I S (MOMENTS) N O R M A L T O C O A S T L I N E P A R A L L E L TO C O A S T L I N E o L o s t S h o e C r e e k 0 Long Beach • C l i f f A Qu is i t i s Point * Berm* j * B e r m + M. K T . V B e a c h A Wya Point * M.W.L.J • B a y Q O f f s h o r e F I G U R E 12 OLB3 o o O » * OLB2* . A o A — i — -20 — i i — -1-5 • -10 S K E W N E S S — i — -0 -5 -2-5 0-0 0 5 86. D. BEACH SEDIMENTARY ENVIRONMENT It s h o u l d be s t a t e d a t t h e o n s e t t h a t l a r g e s a m p l e s NWR-5 ( a 5 b , c ) were p r o b a b l y c o n t a m i n a t e d by m a t e r i a l f o r -e i g n t o t h e e n v i r o n m e n t , due t o dumping a t t h i s l o c a t i o n by a l o c a l b u i l d i n g c o n t r a c t o r p r i o r t o s a m p l e c o l l e c t i o n . I. SUMMER CHANGES C o n s i d e r a t i o n o f t h e s t a t i s t i c a l p a r a m e t e r s o f l a r g e s a m p l e s f rom t h e f o r e s h o r e (Map I, F i g u r e 13 ) , l e a d s t o t h e f o l l o w i n g o b s e r v a t i o n s : S p i t b a r s a m p l e s S E R - I ( b + c ) - S E R - 4 ( b +c ) a r e s l i g h t l y f i n e r and b e t t e r s o r t e d t h a n t h e s a m p l e s i m m e d i a t e l y n o r t h w e s t o f t h e mouth o f L o s t Shoe C r e e k , NWR-I(b + c ) - (NWR-Mb + c ) . T h i s s u g g e s t s l i t t o r a l d r i f t t o w a r d s t h e s o u t h e a s t i n t h e v i c i n i t y o f t h e s p i t b a r - a d i r e c t i o n o p p o s i t e t o t h a t w h i c h w o u l d p r o m o t e i t s " g r o w t h " ( s e e c h a p t e r on PLANIMETRIC SHAPE ) . T h i s d e d u c t i o n r e f l e c t s t h e t r a n s i e n t n a t u r e o f d r i f t d i r e c t i o n s a l o n g t h i s p a r t o f t h e b e a c h ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS) . Samp le SER-6(b + c ) , l o c a t e d on Sand P o i n t , i s f i n e r and b e t t e r s o r t e d t h a n a d j a c e n t s a m p l e s SER-5(b + c ) and SER-7(b + c ) . T h i s i n d i c a t e s d e p o s i t i o n a t Sand P o i n t and e r o s i o n on e i t h e r s i d e o f i t ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). Samp le S E R - 4 ( b + c ) , c o l l e c t e d n e a r P r o f i l e C , i s more 8 7 . n e g a t i v e l y skewed and I e p t o k u r t i c t h a n any o f t h e o t h e r f o r e -s h o r e s a m p l e s . T h i s means t h a t w i n n o w i n g o f f i n e m a t e r i a l by t h e s w a s h - b a c k w a s h i s most e f f i c i e n t i n t h i s a r e a . H i s t o g r a m p l o t s o f t h e s m a l l p r o f i l e s a m p l e s (Map I, F i g u r e s 14a, 16a, 18a, 2 0 a , 2 2 a , 2 4 a , 26a) i n d i c a t e t h e f o l l o w -i ng : A l i t t l e g r a v e l p e r s i s t e d on t h e f o r e s h o r e a t a few l o c a t i o n s e v e n t h o u g h i t was t h e n i n a s t a t e o f e q u i l i b r i u m . The d i s t r i b u t i o n o f v e r y f i n e s and (1 /16 - 1/8 mm) a c r o s s t h e p r o f i l e l i n e s i s i n d i c a t i v e o f t h e h y d r o d y n a m i c c o n d i -t i o n s a t e a c h l o c a t i o n . At P r o f i l e s D and E, g r a n u l e s and a few p e b b l e s e x i s t e d a t t h e l a n d w a r d end o f t h e two p r o f i l e s , and v e r y f i n e s and was c o n -c e n t r a t e d a t t h e s e a w a r d e n d s . T h i s was due t o h i g h waves e r o d i n g t h e s e a w a r d edge o f t h e w i n t e r b e r m , and t r a n s p o r t i n g a l l but t h e c o a r s e s t m a t e r i a ! down t h e f o r e s h o r e s ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). At P r o f i l e s A and G, s h e l l - h a s h e x i s t e d n e a r t h e m i d d l e o f t h e p r o f i l e l i n e s , and so t o o d i d t h e h i g h e s t c o n c e n t r a t i o n o f v e r y f i n e s a n d . The r e a s o n f o r t h i s was b e c a u s e o f a b u n d a n t s h e l l y m a t e r i a l ( s e e c h a p t e r on MARINE L I F E ) , and s m a l l waves a f f e c t i n g t h e s e a r e a s ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). At P r o f i l e s B, C and F, no g r a v e l was p r e s e n t , and v e r y f i n e s and was s p r e a d e r r a t i c a l l y a c r o s s t h e f o r e s h o r t . T h i s r e s u l t e d f r o m weak, v a r i a b l e l i t t o r a l c u r r e n t s i n th - 3 se a r e a s ( s e e * S e e GLOSSARY 8 8 . c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). 2. WINTER CHANGES L a r g e s a m p l e s c o l l e c t e d f r o m t h e b a c k s h o r e ( w h i c h was e s t a b l i s h e d d u r i n g t h e p r e c e e d i n g w i n t e r ) , i n d i c a t e t h e fo I lowi ng : Sample NWR-6a, l o c a t e d b e t w e e n P r o f i l e s A and B, was t h e o n l y o n e w i t h t e x t u r a l p r o p e r t i e s i d e n t i c a l t o t h e f o r e -s h o r e s e d i m e n t d e p o s i t e d d u r i n g t h e summer. T h i s i n d i c a t e s p e r s i s t e n c e o f a s o u t h e a s t m o v i n g l i t t o r a l c u r r e n t i n t h i s r e g i o n d u r i n g t h e w i n t e r , and no a d d i t i o n o f m a t e r i a l f r o m t h e c l i f f ( s e e c h a p t e r on PLAN IMETRIC SHAPE ) . Samp le s l o c a t e d a l o n g t h e c r e s t o f t h e s p i t b a r , S E R - l a -S E R - 4 a , show no c l e a r p a t t e r n w i t h r e s p e c t t o t h e s a m p l e s i m m e d i a t e l y n o r t h w e s t o f t h e mouth o f L o s t Shoe C r e e k , NWR-1 a - NWR-4a. T h i s i n d i c a t e s a c o m p l e x i n t e r p l a y o f h i g h e n e r g y waves w i t h o u t f l o w f r o m t h e r i v e r . Samp le S E R - 6 a , l o c a t e d on Sand P o i n t , i s c o a r s e r and s l i g h t l y l e s s w e l l s o r t e d t h a n a d j a c e n t s a m p l e s S E R - 5 a and S E R - 7 a , i n d i c a t i n g more i n t e n s e e r o s i o n a t t h i s l o c a t i o n t h a n on e i t h e r s i d e o f i t . I t t h u s seems a p p a r e n t t h a t m a t e r i a l d e p o s i t e d on Sand P o i n t d u r i n g t h e summer, i s s t r o n g l y e r o d e d d u r i n g t h e w i n t e r / s p r i n g s t o r m p e r i o d . T h i s a c c o u n t s f o r t h e b a t h y m e t r i c e x t e n s i o n o f Sand P o i n t i n t o t h e bay p a s t S e a l Rock ( s e e h e a d i n g on BAY BATHYMETRY). Samp le S E R - 4 a i s a l s o more n e g a t i v e l y skewed and l e p t o k u r t i c 89. than any o f the o t h e r back sho re s amp le s , i n d i c a t i n g t h a t : even d u r i n g w i n t e r , t he winnowing p r o c e s s o f swash-backwash i s most e f f i c i e n t at t h i s l o c a t i o n . Smal l p r o f i l e samples c o l l e c t e d d u r i n g the s u c c e e d i n g w i n t e r (Map I, F i g u r e s 14a, 16a, 18a, 22a, 24a, 26a) show the f o l l o w i n g changes : At P r o f i l e s D and E, the fo rmer c o n s i s t e d e n t i r e l y o f g r a v e l a t i t s landward end , and the l a t t e r po s -s e s s ed r e l a t i v e l y l e s s near t he m i d d l e o f t he p r o f i l e l i n e , and medium sand a t i t s landward end. T h i s i n d i c a t e s t h a t t h e h e i g h t o f waves a f f e c t i n g P r o f i l e E d u r i n g the w i n t e r i s l e s s than a t P r o f i l e D - a s i t u a t i o n wh ich a l s o e x i s t s d u r i n g the summer ( s ee c h a p t e r on TRANSVERSE PROFILES). At P r o f i l e s A and G, no s h e l l - h a s h was p r e s e n t , and the h i g h e s t c o n c e n t r a t i o n o f v e r y f i n e sand o c c u r r e d a t t h e landward end o f t he p r o f i l e l i n e s . T h i s means t h a t waves a f f e c t i n g the two a rea s were o n l y s l i g h t l y h i g h e r than t ho se measured d u r i n g the summer ( see c h a p t e r on SAND MOVEMENT CASED ON WAVE PARAMETERS). At P r o f i l e s B, C and F the c o a r s e s t m a t e r i a ! o c c u r r e d a t t he landward end o f t he p r o f i l e l i n e s , and t h e v e r y f i n e sand f r a c t i o n s i n -c r e a s e d i n a seaward d i r e c t i o n , T h i s s i m p l y r e f l e c t s b e a c h d e g r a d a t i o n by l a r g e waves. P r o f i l e C was by f a r t he c o a r s e s t o f t he t h r e e l i n e s and comparab le t o P r o f i l e D i n t e x t u r e , t hu s i n d i c a t i n g t he s e v e r i t y o f wave a t t a c k at t h i s l o c a t i o n ( see c h a p t e r on TRANSVERSE PROFILES). 90. 3. CONCLUSIONS In summer, f i n e . , l i g h t c o l o u r e d s and c h a r a c t e r i z e s t h e e n t i r e f o r e s h o r e e x c e p t f o r two s m a l l g r a v e l l y a r e a s a d -j a c e n t t o Sand P o i n t , and t h e two d i s t a l ends o f t h e b e a c h , t h e n o r t h w e s t and s o u t h e a s t c o r n e r s , w h i c h c o n t a i n e d some she I I - h a s h . In w i n t e r , t h e c e n t r a l p o r t i o n o f t h e b e a c h i s r e d u c -ed t o c o a r s e g r a v e l , a l m o s t a l l o f t h e s and b e i n g t r a n s p o r t e d o u t t o t h e m i d d l e o f t h e b a y . At P r o f i l e s B and F, t h e b e a c h becomes l a r g e l y composed o f m e d i u m - g r a i n e d b l a c k s a n d , a n d t h e two d i s t a l ends r e m a i n e s s e n t i a l l y u n a l t e r e d f r o m t h e f i n e -g r a i n e d , l i g h t - c o l o u r e d , s andy c o n d i t i o n s t h a t p r e v a i l d u r i n g t h e summer. L lUOST SH < N W R SAMPLE LINE N*S • 6 5 4 3 2 1, i i i i i i . O N G S H O R E S E D I M E N T P A R A M E T E R S DE CREEKl (MOMENTS) ISANDPOINTI S E R | ,1 2 3 4 5 6 7 8 M i l l 1 1 - i i M E A N 0 , c o a rser 3-0 fr p — o - - „ 15 \ . 0 S I D E Y i.-npr sort oved i n g 20 * '^^-^ " •as ^^^^^y^^^X. < * ^ ° ^ ° v > s symmc S K E W • n e g a t r l c a l t i v e -3-0 ^ \ -4.0 Y mo lepto^ KURT re t u r t l e i /\ / \ / \ y \ •400 ' \ / \ / \ . y \ •200 v / \ * \ y \ ^ APPROXIMATE HORIZONTAL SCALE: l" = 1875' F I G U R E 1 3 o — — — o BERM (a) o— o FORESHORE (b).(c) 92. VI I. TRANSVERSE PROFILES A . INTRODUCTION A l a r g e number o f i n v e s t i g a t i o n s have b e e n made 6h t h e t r a n s v e r s e c h a n g e s o f b e a c h e s r e s u l t i n g f r o m s e a s o n a l o r s t o r m e f f e c t s ( S h e p a r d and L a F o n d , 1940; Inman, 1953; W i e g e l , P a t r i c k and K i m b e r l e y , 1954; J o h n s o n , 1956; Z i e g l e r and T u t t l e , 1961; P i l k e y and R i c h t e r , 1964; H a r r i s o n , 1 9 6 4 ) , and l a b o r a t o r y i n v e s t i g a t i o n s h a v e been u n d e r t a k e n to e x a m i n e t h e r e l a t i v e i m p o r t a n c e o f t i d a l r a n g e and wave s t e e p n e s s i n d e -t e r m i n i n g e q u i l i b r i u m p r o f i l e s (Wa t t s and D e a r d u f f , 1954; R e c t o r , 1954 ) . The p r e s e n t s t u d y was c o n d u c t e d t o d e t e r m i n e t h e n a t u r e and m a g n i t u d e o f f o r e s h o r e p r o f i l e c h a n g e s a t Wreck B a y , d u r i n g t h e summer r e g i m e . An a t t e m p t was made t o i s o l a t e t h e v a r i o u s wave and t i d a l f a c t o r s c o n t r o l l i n g p r o f i l e d e v e l o p m e n t , and a summer s t o r m i n m i d - A u g u s t p r o v i d e d i n f o r m a t i o n on f o r e -s h o r e s t a b i l i t y u n d e r v i o l e n t h y d r o d y n a m i c c o n d i t i o n s . A s i n g l e s e t o f m e a s u r e m e n t s o b t a i n e d d u r i n g t h e w i n t e r o f 1968/ 1969 a l l o w e d a s s e s s m e n t on s e a s o n a l c h a n g e s t h a t m i g h t be e x -p e c t e d t o o c c u r on t h e b e a c h . B. F IELD TECHNIQUES Seven t r a n s v e r s e p r o f i l e s , numbered A t o G , were e s -t a b l i s h e d a c r o s s t h e f o r e s h o r e a t l o c a t i o n s shown on Map I. Rod #1 o f e a c h p r o f i l e was p l a c e d j u s t s e a w a r d o f t h e u p p e r l i m i t o f swash a c t i v i t y d u r i n g a p e r i o d o f s p r i n g t i d e s i n * S e e GLOSSARY 93. J u n e 1968. The o t h e r r o d s were s p a c e d f r o m 25 t o 150 f e e t a p a r t , d e p e n d i n g on t h e w i d t h and c h a r a c t e r o f t h e f o r e s h o r e . T h i s was a c c o m p l i s h e d u s i n g a K e u f f e l and E s s e r c l o t h t a p e , and no c o r -r e c t i o n was made f o r h o r i z o n t a l d i s t a n c e . The rod s were o f I i n c h s t e e l , c u t i n t o 4 f o o t l e n g t h s , They were e m p l a c e d on t h e f o r e s h o r e so t h a t e x a c t l y 2 .00 f e e t p r o t r u d e d a b o v e t h e s and s u r f a c e . At t h e c l i f f b a s e , and c l o s e l y i n l i n e w i t h e a c h p r o f i l e , a 6 i n c h s p i k e was d r i v e n i n t o t h e s tem o f a l i v i n g t r e e . T h e s e s p i k e s s e r v e d as p e r m a n e n t r e f e r e n c e p o i n t s f o r l o c a t i n g t h e r o d s t a t i o n s i n w i n t e r , when most o f them were d e s t r o y e d by l a r g e w a v e s . The r e l a t i v e e l e v a t i o n s o f r o d t i p s and r e f e r e n c e s p i k e s o f e a c h p r o f i l e were d e t e r m i n e d by p l a n e t a b l i n g i m m e d i a t e l y a f t e r t h e i r e m p l a c e m e n t . T h e s e v a l u e s were l a t e r t i e d i n t o t h e r e g i o n a l s u r v e y o f t h e b e a c h , t o o b t a i n t h e i r t r u e e l e v a t i o n s a b o v e sea l e v e l ( s e e h e a d i n g TOPOGRAPHY OF WRECK B A Y ) . D u r i n g t h e summer, c h a n g e s i n s and l e v e l were m e a s u r e d t o an a c c u r a c y o f 0.01 o f a f o o t w i t h r e s p e c t t o t h e r o d t i p s , u s i n g a g r a d u a t e d s t a f f ( P l a t e 10) . In w i n t e r , a s i n g l e s e t o f f o r e s h o r e e l e v a t i o n s were m e a s u r e d w i t h a dumpy I e v e I. C. STUDY AREAS M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f t h e s e v e n p r o f i l e s a r e shown i n F i g u r e s 14b, 16b, 18b, 2 0 b , 2 2 b , 24b and 2 6 b , and t h e t i m e d e v e l o p m e n t o f e a c h i s i l l u s t r a t e d i n F i g u r e s 15, 17, 19, 2 1 , 2 3 , 25 and 27 . 94, I. SUMMER CHANGES P r o f i l e s D and E, l o c a t e d a d j a c e n t t o Sand P o i n t , were a f f e c t e d by l a r g e waves t h a t b r o k e a t m o d e r a t e l y w i d e a n g l e s t o t h e b e a c h ( T a b l e X ) „ B o t h a r e a s were c h a r a c t e r i z e d by t h e same p r o f i l e c h a n g e s , v i z „ e r o s i o n o f t h e u p p e r and l ower f o r e s h o r e , and r i d g e - b u i l d i n g i n t h e m i d - f o r e s h o r e r e g i o n . The c h a n g e s w h i c h t o o k p l a c e a t P r o f i l e E were some-what l e s s p r o n o u n c e d t h a n a t P r o f i l e D, b e c a u s e t h e waves were l e s s v i o l e n t , and a l s o b e c a u s e t h e w i n t e r berm was l e s s e x t e n -s i v e . E r o s i o n o f t h e l a t t e r p r o v i d e d a l a r g e p o r t i o n o f t h e m a t e r i a l u s e d i n b u i l d i n g t h e r i d g e s . In l a t e s p r i n g , b o t h a r e a s p o s s e s s e d w i d e , f l a t p l a t f o r m s j u s t s e a w a r d o f t h e p r o -f i l e l i n e s . A t P r o f i l e D, t h e p l a t f o r m was r a p i d l y t r a n s f o r m e d i n t o a l o n g s h o r e b a r , w h i c h p r e v a i l e d t h r o u g h o u t t h e summer u n t i l a v i o l e n t s t o r m a t t a c k e d t h e b e a c h on t h e 18th A u g u s t , r e v e r t i n g i t b a c k t o i t s o r i g i n a l f o r m . A l o n g s h o r e b a r s e a -ward o f P r o f i l e E was n e v e r d i r e c t l y o b s e r v e d , b u t t h e p r e s e n c e o f o n e was s u g g e s t e d by t h e f a c t t h a t waves b r o k e i n t h i s v i c i n i t y , and t h e n r e f o r m e d c l o s e r t o s h o r e . The s e n s i t i v i t y o f t h e s e p r o f i l e s t o t i d a l r ange may be d e s c r i b e d as m o d e r a t e , b o t h o f them s h o w i n g s l i g h t a c c r e t i o n on t h e u p p e r f o r e s h o r e d u r i n g low neap - low s p r i n g t i d e p e r i o d s ( F i g u r e s 21 and 23). The two p r o f i l e s l o c a t e d a t t h e d i s t a l ends o f t h e b e a c h , P r o f i l e s A and G, were b o t h s u b j e c t e d t o v e r y s m a l l waves w h i c h i m p i n g e d on t h e b e a c h a t w i d e a n g l e s ( T a b l e X ) . 9 5 . S i m i l a r c h a n g e s o c c u r r e d i n t h e s e a r e a s as w e l l , v i z . e r o s i o n o f t h e l ower f o r e s h o r e , and b e r m - b u i I d i n g on t h e u p p e r f o r e -s h o r e . Changes a t P r o f i l e A were l e s s p r o n o u n c e d t h a n a t P r o f i l e G due t o r e l a t i v e l y s m a l l e r waves a f f e c t i n g t h i s a r e a . F u r t h e r -m o r e , g r e y c l a y was i n t e r m i t t e n t l y e x p o s e d a l o n g t h e l ower f o r e s h o r e h e r e , i n d i c a t i n g a v e r y t h i n c o v e r o f s a n d a b o v e b a s e m e n t . A t P r o f i l e G , a summer berm was b u i l t t o s u c h a h e i g h t , t h a t t h e u p p e r f o r e s h o r e was no t a f f e c t e d by t h e s t o r m on t h e 18th A u g u s t . T h e s e p r o f i l e s may be d e s c r i b e d as b e i n g m o d e r a t e l y s e n s i t i v e t o t i d a l r a n g e as w e l l , b o t h s h o w i n g s l i g h t a c c r e t i o n on t h e u p p e r f o r e s h o r e d u r i n g low s p r i n g t i d e p e r i o d s ( F i g u r e s 15 and 2 7 ) . P r o f i l e s B, C and F were a l l a f f e c t e d by m o d e r a t e l y l a r g e waves w h i c h i m p i n g e d on t h e b e a c h a t v e r y s m a l l a n g l e s ( T a b l e X ) „ G r o s s p r o f i l e c h a n g e s were a l l s i m i l a r i n t h a t a c -c r e t i o n p e r s i s t e d a c r o s s t h e e n t i r e f o r e s h o r e . The a r e a a r o u n d P r o f i l e B d i s p l a y e d e x t r e m e s e n s i t i v i t y t o t i d a l r a n g e , w h e r e a s t h e o t h e r a r e a s were v i r t u a l l y i n s e n s i t i v e . At P r o f i l e B, t h e u p p e r f o r e s h o r e was e r o d e d d u r i n g s p r i n g t i d e s , and b e r m - b u i I d i n g and c u s p d e v e l o p m e n t commenced d u r i n g low neap - low s p r i n g t i d e p e r i o d s ( F i g u r e 17 ) . At P r o f i l e C , berm b u i l d i n g was i n h i b i t e d by t h e p r e s e n c e o f a r e l i c t c o b b l e c u s p on t h e u p p e r f o r e s h o r e ( F i g u r e 3 5 ) , and a t P r o f i l e F , u n i n t e r -r u p t e d f o r e s h o r e a c c r e t i o n r e s u l t e d i n a w e l l d e f i n e d berm a t i t s l a n d w a r d end ( F i g u r e 2 4 b ) . 96, G e n e r a l f o r e s h o r e a c c r e t i o n c a n be s een a t t h e mouth o f L o s t Shoe C r e e k where s t r e a m e r o s i o n c u t s through t h e b e a c h s a n d a t e a c h low t i d e p e r i o d ( P l a t e s I l a and l i b ) . 2. WINTER CHANGES C l i f f u n d e r c u t t i n g as a r e s u l t o f wave a c t i o n was nowhere i n e v i d e n c e i n e a r l y F e b r u a r y 1969. The b a c k s h o r e howr e v e r , a p p e a r e d t o d i p u n i f o r m l y s e a w a r d f r o m t h e c l i f f b a s e a t e a c h p r o f i l e l o c a t i o n . Removal o f m a t e r i a l f r o m t h e b a c k s h o r e r e s u l t e d i n a c c r e t i o n o v e r t h e f o r e s h o r e , t h e r e b y c r e a t i n g a b e a c h f a c e t h a t s l o p e d more g e n t l y s e a w a r d t h a n t h e c o r r e s p o n d i n g summer p r o f i l e . T h i s g e n e r a l t r e n d was e v i d e n t a l l a l o n g t h e b e a c h e x c e p t i n t h e v i c i n i t y o f P r o f i l e F , where no p r e c e e d i n g w i n t e r berm had e x i s t e d on t h e b a c k s h o r e d u r i n g t h e summer ( s e e c h a p t e r on BEACH STRUCTURES) . T h e r e was t h u s no m a t e r i a l a v a i l a b l e a t t h i s l o c a t i o n f o r f o r e s h o r e a c c r e t i o n , and t h e p r o f i l e t h e r e f o r e showed a s l i g h t i n c r e a s e . i n b e a c h s l o p e . F i g u r e 14a. H i s t o g r a m p l o t s o f s m a l l s a m p l e s f r o m P r o f i l e A, - T h e s e s a m p l e s r e p r e s e n t s u r f i c i a l f o r e s h o r e s e d i m e n t a r y c o n d i t i o n s d u r i n g t h e summer and w i n t e r r e g i m e s . - Each h i s t o g r a m d e p i c t s a r od s t a t i o n s a m p l e s c r e e n e d a t I 0 i n t e r v a l s . - Rod numbers a r e i n d i c a t e d by c i r c l e d n u m e r a l s b e t w e e n t h e two h i s t o g r a m c o l u m n s . - The f o r e s h o r e s l o p e a t e a c h rod s t a t i o n i s shown by f i g u r e s a d j a c e n t t o t h e b o t t o m r i g h t -hand c o r n e r o f t h e h i s t o g r a m s , i n d e g r e e s . - The number o f g r a v e l p a r t i c l e s i n t h e s a m p l e s i s i n d i c a t e d on t h e ? 4 mm h i s t o g r a m b l o c k ; M = many. - F i g u r e s 16a, 18a, 2 0 a , 2 2 a , 2 4 a , 26a a r e s i m i -l a r p r e s e n t a t i o n s o f P r o f i l e s B, C f D, E, F , G r e s p e c t i v e l y . F i g u r e 14b. M o r p h o l o g i c a l c h a r a c t e r i s t i c s o f P r o f i l e A a t f o u r d i s c r e t e t i m e s . - C i r c l e d n u m e r a l s a l o n g t h e a b s c i s s a d e n o t e r o d l o c a t i o n s . B o t h axe s o f t h e d i a g r a m a r e g r a d -u a t e d i n f e e t , and v e r t i c a l e x a g g e r a t i o n i s 20 X. - The f i r s t c u r v e , f o r 12 J u n e 1968, r e p r e s e n t s t h e p r o f i l e on t h e day o f r o d e m p l a c e m e n t . The o t h e r t h r e e c u r v e s have a l l b e e n p l o t t e d a t e q u i v a l e n t t i m e s w i t h r e s p e c t t o t i d a l r ange -a t low s p r i n g t i d e . The 22 Augu s t c u r v e , how-e v e r , d e p i c t s t h e b e a c h p r o f i l e s h o r t l y a f t e r a summer s t o r m , and t h e 3 F e b r u a r y 1969 c u r v e i s t h e w i n t e r b e a c h p r o f i l e , when s t o r m f r e -q u e n c y was h i g h e s t . - The w a t e r t a b l e (WT) l i n e o f e m e r g e n c e i s i n -d i c a t e d f o r t h e two summer c u r v e s - 26 J u l y 1968 and 22 A u g u s t 1968. Mean h i g h t i d e (MHT) . mean w a t e r l e v e l (MWL) and mean low t i d e (MLT) v a l u e s a r e shown as h o r i z o n t a l l i n e s a c r o s s t h e d i a g r a m . - F i g u r e s 16b, 18b, 2 0 b , 2 2 b , 2 4 b , 26b a r e s i m i -l a r r e p r e s e n t a t i o n s o f P r o f i l e s B, C , D, E, F , G r e s p e c t i v e l y . no 10-0 s.o — © © © <Z) © © © •T lOfr-O T 2QOO T 300.CJ T 1 1 1 1 j 1 1 1 1 1 1 1 1 1 1 1 1 1 l F I FEET FROM CLIFF v\ V WT -MWL P R O F I L E @ •• Late spring 12 June 1968 ••• Early summer 26July 1968 "• Mid summer 22 Aug. 1969 » Late winter 3 Feb. 1969 M HT \ - v k — - MLT F I G U R E 1 4 b W I N T E R 75 SO 23 75 SO 23 73 SO 25 h=J2.0* 17* tdis* 1.1* 4 1 I 1^  I, mm JOT* P R O F I L E ® S U M M E R — 26 July 1968 W I N T E R — 3 Feb. 1969 F I G U R E 1 4 a F i g u r e 15. F o r e s h o r e m o d i f i c a t i o n a t P r o f i l e A as a f u n c t i o n o f t i m e , - C i r c l e d n u m e r a i s a l o n g t h e u p p e r l e f t - h a n d edge o f t h e d i a g r a m d e n o t e rod number s . O r d i n a t e g r a d u a t i o n s a r e s c a l e d i n f e e t o f a c c r e t i o n o r e r o s i o n a t any r o d s t a t i o n . - F o r e s h o r e e l e v a t i o n a t e a c h r o d s t a t i o n was p l a c e d a t z e r o on t h e day o f r o d e m p l a c e m e n t ; a l l s u c c e e d i n g f o r e s h o r e m e a s u r e m e n t s were b a s e d on t h i s . - In o r d e r t o m i n i m i z e c u r v e d i s t o r t i o n r e s u l t i n g f r o m s h o r t - t e r m wave e f f e c t s , f o r e s h o r e e l e v a -t i o n s p l o t t e d on t h e d i a g r a m s a r e a v e r a g e s o f t h r e e c o n s e c u t i v e f i e l d m e a s u r e m e n t s : t h e s p e c i f i c o n e , and t h e p r e c e e d i n g and s u c c e e d i n g o n e s . T h e s e v a l u e s have been j o i n e d by s o l i d l i n e s t o f o r m t h e c u r v e . H o w e v e r , when e i t h e r t h e p r e c e e d i n g o r s u c c e e d i n g f i e l d m e a s u r e m e n t s were s p a c e d by f o u r o r more day s f r om t h e s p e c i f i c o n e , t h e v a l u e o f t h e l a t t e r was p l o t -t e d d i r e c t l y o n t o t h e d i a g r a m , and a d o t t e d l i n e drawn b e t w e e n i t and t h e d i s t a n t f i e l d v a l u e . - S i n g l e m e a s u r e m e n t s made d u r i n g t h e w i n t e r a r e shown e n c l o s e d i n c i r c l e s a t t h e r i g h t - h a n d s i d e o f t h e d i a g r a m . - The t i d a l r ange c u r v e d e p i c t e d a t t h e b o t t o m o f t h e d i a g r a m , was p l o t t e d f r o m p o i n t s o b t a i n e d by s u b t r a c t i n g e a c h d a y ' s l ower low t i d e v a l u e f r o m i t s h i g h e r h i g h t i d e v a l u e . - F i g u r e s 17, 19, 2 1 , 2 3 , 2 5 , 27 a r e s i m i l a r p r e s e n t a t i o n s o f P r o f i l e s B, C , D, E, F, G r e s p e c t i v e I y . J O N E J U L Y AUGUST 196S FEB. 1969 15 20 25 30 5 10 15 20 25 30 5 10 15 20 25 30 11 11 11 j i i 11 | 11 »i '• i i i | r r n p T f F j r i i i j r r n j-r-rrt-j T r r TTTI I I [ i I l » | 1 T f I | i i 1 I | t t i t | © LU LU LL 130 120 | 110-10-C-l / \ / \ 9 0 -8 0 -7 0 -6 0 -5 0 -I A. . • o V \7 N V T I D A L R A N G E O © © © © © © © © ,T, X "jM> • , T, aopo ,T , , I, nnrffl ,T , , , , , , T, *9°9 , T FEET FROM CLIFF P R O F I L E ( i ) • - — - • Late spring 12 June 1968 • • Early summer 26July 1968 •• ~* Mid summer 22 Aug. 1968 « • Late winter 2 Feb. 1969 F I G U R E 1 6 b S U M M e R W I N T E R 73 •/. 30 23 73 •/. 30 23 75 •/. 50 25 73 •/. SO 25 75 V. SO 25 73 •/. 50 23 75 V. 30 25 73 50 25 75 •/. 30 23 © 46* 19* 32* © 2cr 1-4* 0-5* © 1=1-0.4* 1.4* 1-2* 73 V. SO 23 75 •/. 50 25 75 •/. 50 25 75' •/. SO 25< 7 •/. SO 2 75 •/. SO 25 75 1. 30 23 46* 34* 1-tf 13* I f 10* J=l2f/ 4 2 ' ''2 % 'fe 't PROF ILE S U M M E R — 26 July 1968 W I N T E R — 2 Feb. 1969 F I G U R E 1 6 a 4 J ' llj \ Vs mm F I G U R E 17 P R O F I L E Cg) S U M M E R W I N T E R 75 SO 23 75 'U SO 25 75 •/. SO 25 75 SO 25 75 •/. 50 25 75 25 75 V. 50 25 (2d) J J , 75 V. 50 25 75 V. 50 25 75 •/. 50 25 31* 0-7* LOT 4 5 ' 36* 75 4 2 I I, I, I, I, 35* \ i '<* l» PROFILE 10* S U M M E R - 2 6 July 1968 W I N T E R — 2 F«t> 1969 © the 4 2 ' WW F I G U R E 1 8 a FIGURE 2 0 b S U M M E R W I N T E R 75 •/. 50 23 75 •/. SO 25 Lll 75 V. 30 25 73 V. 30 23 •/. 50 25 73 •/. 30 23 73 50 25 J7.CT 4.1* 1 3T 75 V. SO 25 73 •/. 50 25 J3S* 31* 3-1* mm. © 12* 20- P R O F I L E © S U M M E R — 26 July 1963 W I N T E R — 2 FeD. 1969 26* 75 •/. 30 23 FIGURE 2 0 a O FIGURE 22b SUMMER W I N T E R 75 7. 30 25 0 •/. SO 73 •/. 50 25 m d 73 7. 30 25 73 •/. 30 25 73 •/. 30 23 J6-2* 3 B f J2-S* © 73 7. SO' 2! 73 7. SO 25 73 7. SO 25 ' B u d 1 r 4 i f 32* 20* 17* \ \ \ \ JlV 75 7. 30 23 75 7. 30 25 © 4 2 I b I, I, \ \ \ \ '<* 307* P R O F I L E SUMMER -26 Jul/ 1968 WINTER— 2 Feb. 1969 FIGURE 22a FIGURE 23 P R O F I L E (E) (D (2) . ® ® © — , i ° ° 0 , — J L . — , m-9 , r-L 2S.O 20.0 IS.O — 10.0 — so — S U M M E R 73 •/. 30 25 75 •/. SO 25 75 •/. =0 25 75 •/. 5 0 25 75 V, 50 25 73 30 25 75 •/. SO 25 75 •;. so 23 73 •/. 30 23 © 29" 0 3 " 2 3" &9* 08" 1-Cf 10* 4 2 I l> 1/ 1/ I, 75 V. SO 25 75 V. 30 25' 73 •/. 30 25 W I N T E R OLh 2.8* 3 4 * 25* 4) V. SO 25 75 V. SO 25 73 •/. 50 23 JJ 20* bdi.af © 4 3 '4 \'t PROF ILE © S U M M E R — 26 July 1968 W I N T E R — 1 Fetx 1969 F I G U R E 2 4 a O F I G U R E 2 5 P R O F I L E © J U N E JULY AUGUST 1968 F E B . ^ 9 6 9 15 2 0 25 30 5 10 15 2 0 25 30 5 10 15 20 25 30 . - ' 1 •I 1 " 1 I ' • " I 1 1 I ' 1 " I " ' I 1 1 I ' ' " I' ' 1 • I ' ' " I' ' '' )' • " | LU LU Lu © 13 0 120 -110 -, 100-9 0-ao-7 0 6 0 -•v A / \ A 1 - ^ V \ / v \ / n A i \ / V R A N n F Q © ® © © © © T | 1 T , »Qp.g J , , T , »y-B4 p"T^ FEET FROM CLIFF M.O — P R O F I L E (S) Latt spring 14 June 1968 •—•—• Early summer 26July 1968 *" • Mid summer 22 Aug. 1968 ' • Late winter 1 Feb. 1969 SCO — -MWL 5.0 — ' MLT  FIGURE 2 6 b o»— S U M M E R W I N T E R 75 •/. 30 25 75 V. 30 25 73 V. 30 25 73 V. SO 25 75 V, SO 25 73 V. 30 25 75 V. 50 25 © 06* 26 ' 1-9* 75 V. SO 25 75 •/. SO 25 75 •/. SO 25 ( ^ ) •/. 50 18* 18* 13* 4 , I U H mm. © 73 •/. 30 23 73 V. 50 25 75 •/.' SO 23 12* 16* 4* 10* tdi-3* 1.3* 1-3* = » 9 * 4 2 ''4 \ '<6 PROFILE S U M M E R — 26 July 1966 W I N T E R — 1 Feb. 1969 FIGURE 26a FIGURE 27 P R O F I L E (g) I I I . 3. STORM CHANGES A s e v e r e s t o r m a t t a c k e d t h e b e a c h i n t h e e a r l y h o u r s o f t h e 18th A u g u s t 1968, W e a t h e r maps c o m p i l e d by t h e G e o g r a -phy D e p a r t m e n t a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , were e x a m i n e d t o t r a c e t h e t r a c k o f t h e s t o r m c e n t e r , and t o n o t e i t s c h a r a c t e r i s t i c s . On t h e l 4 t h A u g u s t , a s m a l l l o w - p r e s s u r e a r e a d e v e l o p e d i n t h e B a r i n g S e a , w h i c h p a s s e d s l o w l y a c r o s s t h e A l e u t i a n I s l a n d s , and e n t e r e d t h e G u l f o f A l a s k a on t h e 17th A u g u s t . By t h i s t i m e i t had d e v e l o p e d i n t o a m a j o r w e a t h -e r s y s t e m , t h e f r o n t o f w h i c h e x t e n d e d o v e r t h e west c o a s t o f V a n c o u v e r I s l a n d , Winds a l o n g t h e c o a s t a t t h i s t i m e were b e t w e e n 15 and 20 mph f r o m t h e s o u t h e a s t , b u t a p p r o x i m a t e l y 200 mi l e s due west o f Wreck B a y , t h e w i n d s p e e d was 50 mph f rom t h e s o u t h e a s t . By t h e 19th A u g u s t t h e s t o r m had waned i n i n -t e n s i t y , and i t s c e n t e r had moved s o u t h e a s t w a r d s t o t h e W a s h i n g t o n c o a s t . On t h e m o r n i n g o f t h e l 8 t h A u g u s t , waves were o b -s e r v e d b r e a k i n g o v e r t h e s h o a l a r e a j u s t s e a w a r d o f t h e e l o n -g a t e b o u l d e r z o n e , and a b o u t i m i l e f r o m t h e mouth o f L o s t Shoe C r e e k . Depth o f t h e s h o a l i s a p p r o x i m a t e l y 15 f e e t , and t i d e h e i g h t a t t h e t i m e o f o b s e r v a t i o n was abou t 7 f e e t . B a s e d on t h e p r e m i s e t h a t waves b r e a k when w a t e r d e p t h i s k/3 t h e wave h e i g h t (Munk, 19^9; q u o t e d i n S h e p a r d , 1 9 6 3 ) , a w a t e r d e p t h o f 22 f e e t g i v e s a f i g u r e o f I62 f e e t f o r t h e b r e a k e r h e i g h t s i n t h i s r e g i o n . Up t o 8 rows o f b r e a k e r s c o u l d be s een f r o m the t o p o f t h e c l i f f a d v a n c i n g on t h e b e a c h a t any o n e 112. t i m e ( P l a t e 2 ) , and t h e b r e a k e r p e r i o d was f o u n d t o h a v e i n -c r e a s e d f r o m 10 t o 12 s e c o n d s . L i t t o r a l c u r r e n t i n t e n s i t i e s were o b s e r v e d t o be much g r e a t e r t h a n t h a t e n c o u n t e r e d d u r i n g t h e summer, and a t P r o f i l e s B, C and F, t h e c u r r e n t d i r e c t i o n s were o p p o s i t e t o t h e mean summer d i r e c t i o n s ( T a b l e X ) . V a s t p i l e s o f k e l p were d e p o s i t e d on t h e b e a c h where o p p o s i n g l i t t o -r a l c u r r e n t s met ( P l a t e 2 5 a ) . The s t o r m o c c u r r e d d u r i n g a p e r i o d o f low neap t i d e s , when t h e r ange was o n l y a b o u t 6 f e e t ; had i t c o i n c i d e d w i t h a s p r i n g t i d e p e r i o d , b e a c h d e s t r u c t i o n w o u l d have b e e n f a r more s e v e r e . E f f e c t s o f t h e s t o r m on t h e b e a c h a r e shown i n F i g u r e 28. The c h a n g e s i n c u r r e d a r e s u r p r i s i n g l y s i m i l a r t o t h e o v e r a l l summer c h a n g e s ( F i g u r e s 14b, 16b, 18b, 2 0 b , 22b , 2 4 b , 2 6 b ) , p r o b a b l y as a r e s u l t o f t h e s m a l l t i d a l r ange d u r i n g t h e s t o r m . The s c a l e o f a c c r e t i o n and e r o s i o n ( a n t i n o d e s ) how-e v e r , i s much g r e a t e r i n t h e s o u t h e a s t p a r t o f t h e b e a c h ( P r o -f i l e s D, E, F and G) t h a n i n t h e n o r t h w e s t p a r t ( P r o f i l e s A , B, and C ) . The most l a n d w a r d a n t i n o d a l z o n e s a r e a l s o much l o n g e r i n t h e s o u t h e a s t p a r t o f t h e b e a c h r e l a t i v e t o t h e n o r t h w e s t p a r t . The r e a s o n f o r t h e s e d i f f e r e n c e s i s p r o b a b l y due t o t h e f a c t t h a t t h e s o u t h e a s t p a r t o f t h e b e a c h i s d i r e c t -l y e x p o s e d t o a t t a c k f r o m w i n d - b l o w n s t o r m waves o r i g i n a t i n g i n t h e s o u t h e a s t . A n o t h e r d e p a r t u r e f r o m u n i f o r m i t y i s e x h i b i -t e d by ne t a c c r e t i o n a t P r o f i l e s B and G, w h e r e a s t h e o t h e r p r o f i l e s a l l s u f f e r e d ne t e r o s i o n ( s e e t a b u l a t i o n b e l o w 113, F i g u r e 2 8 ) . L i k e l y r e a s o n s f o r t h i s a r e t h a t a t P r o f i l e B, more s a n d was t r a n s p o r t e d i n t o t h e e n v i r o n m e n t by a r e v e r s e d l i t t o -r a l c u r r e n t t h a n c o u l d be removed by backwash e r o s i o n , and a t P r o f i l e G, r e l a t i v e l y s m a l l waves i n t h e l e e o f Wya P o i n t p e r h a p s r e s u l t e d i n o n s h o r e movement o f s a n d . B e c a u s e o f i n c r e a s e d wave l e n g t h s and b r e a k e r h e i g h t s d u r i n g t h e s t o r m , much l a r g e r v o l u m e s o f w a t e r washed up t h e b e a c h f a c e w i t h e a c h swash . The r e t u r n i n g backwash had as a r e s u l t , e x t r e m e e r o s i v e c a p a c i t y , and t h e s andy f o r e s h o r e b e t w e e n P r o f i l e s C and D, and b e t w e e n P r o f i l e s E and F , was r e d u c e d t o c o a r s e g r a v e l . A t t i m e s , t h e backwash e n e r g y was s u f f i c i e n t l y h i g h t o s t o p t h e n e x t i n c o m i n g wave a t t h e b o t t o m o f t h e backwash z o n e , and a h y d r a u l i c jump w o u l d f o r m up t o 2 f e e t h i g h ( s e e h e a d i n g MINOR WAVES ASSOC IATED WITH BEACH STRUCTURES) . F i g u r e 28. P r o f i l e c h a n g e s as a r e s u l t o f t h e summer s t o r m 17-19 A u g u s t I 9 6 8 „ - C i r c l e d l e t t e r s a d j a c e n t t o t h e o r d i n a t e a r e t h e p r o f i l e n u m b e r s , and c i r c l e d n u m e r a l s a l o n g t h e p r o f i l e l i n e s a r e rod number s , - The p r o f i l e s a r e p l o t t e d as s t r a i g h t l i n e s f o r t h e 17th A u g u s t , t h e day p r e c e e d i n g t h e s t o r m , and t h e c u r v e d l i n e s a r e c h a n g e s i n c u r r e d by t h e 19th A u g u s t . - H a t c h u r i n g i n d i c a t e s e r o s i o n ; d o t s i n d i c a t e a c c r e t i o n , - Noda l p o i n t s a r e marked w i t h s h o r t v e r t i c a l l i n e s , and a n t i n o d a l z o n e s by n u m b e r s , t h e l a t t e r b e i n g t h e v o l u m e o f m a t e r i a l a c c r e t e d o r e r o d e d i n c u b i c f e e t . T h e s e v o l u m e s were d e t e r m i n e d by m u l t i p l y i n g t h e a n t i n o d a l a r e a s by a p r o f i l e w i d t h o f I f o o t . - Net v o l u m e c h a n g e s and p r o f i l e l e n g t h s a r e t a b u l a t e d a t t h e b o t t o m o f t h e d i a g r a m . - Rods D6, D7 and E7 were washed o u t d u r i n g t h e s t o r m , and d a s h e d c u r v e s f o r t h e s e p r o f i l e s a r e h y p o t h e t i c a I . S T O R M W A V E E F F E C T S 17 - 19 A u g u s t , 1 9 6 8 -32 -40 TZZZZZZZZZZZZZZZCcrz=~ ML •8 ® -10 CD f e e t 5 0 0 © CD + 3 7 W I O O 2 0 0 © 3 0 0 • 3 4 0 0 ® © ©' © D i s t a n c e f r o m c l i f f b a s e (Tt) 380 535 515 370 350 510 370 N e t a c c r e t i o n o r e r o s i o n ( c u b . f t ) -4 + 56 -28 -134 -118 -67 + 30 FIGURE 28 I 15. D. DISCUSS!ON Change s i n t r a n s v e r s e p r o f i l e s a t Wreck Bay d u r i n g t h e summer a p p e a r t o be a f u n c t i o n o f t h r e e d i s t i n c t f a c t o r s - t h e b r e a k e r a n g l e c f i n c i d e n c e , t h e b r e a k e r h e i g h t , and t h e l i n e o f e m e r g e n c e o f t h e w a t e r t a b l e on t h e b e a c h . U n d e r v i o l e n t h y d r o d y n a m i c c o n d i t i o n s p r e v a l e n t d u r i n g w i n t e r , t h e w a t e r t a b l e f a c t o r becomes i n s i g n i f i c a n t , and t h e b r e a k e r h e i g h t becomes t h e d o m i n a n t c o n t r o l l i n g i n f l u e n c e . The a n g l e o f b r e a k e r i n c i d e n c e a p p a r e n t l y d e t e r m i n e s t h e a v a i l a b i l i t y o f s and i n t h e v i c i n i t y o f t h e p r o f i l e s , and i n d i r e c t l y c o n t r o l s t h e i r s e n s i t i v i t y t o t i d a l r a n g e : At P r o f i l e s D, E and A , G , t h e a n g u l a r a p p r o a c h o f b r e a k e r s i s g r e a t e r t h a n o r e q u a l t o 3 ° ( T a b l e X ) , and as a r e s u l t p o r t i o n s o f t h e f o r e s h o r e a c c r e t e a t t h e e x p e n s e o f o t h e r s , and t h e i r s e n s i t i v i t y t o t i d a l r ange i s m o d e r a t e . At P r o f i l e s B, C and F , t h e b r e a k e r a n g l e o f i n c i d e n c e i s l e s s t h a n 3 ° ( T a b l e X ) , and a c c r e t i o n o c c u r s a c r o s s t h e e n t i r e f o r e s h o r e . S e n s i t i v i t y t o t i d a l r a n g e i s e x t r e m e a t P r o f i l e B, and P r o f i l e s C and F a r e v i r t u a l l y i n s e n s i t i v e . T h i s a p p a r e n t c o n t r a d i c t i o n i s e x p l a i n e d by t h e f a c t t h a t a t P r o f i l e B, t h e b r e a k e r i n c i d e n t a n g l e i s s m a l l b u t c o n s i s t e n t , wherea s a t P r o f i l e s C and F , t h e a n g l e s a r e v e r y s m a l l and h i g h l y v a r i a b l e ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). To s u m m a r i s e t h e n , t h e f o r e s h o r e i s most s e n s i t i v e t o t i d a l r a n g e where s and i s a b u n -d a n t , and l i t t o r a l c u r r e n t s a r e weak and u n i f o r m ; i t i s 116. i n s e n s i t i v e where l i t t o r a l c u r r e n t s a r e weak and v a r i a b l e , and m o d e r a t e l y s e n s i t i v e where sand i s s c a r c e . The b r e a k e r h e i g h t d e t e r m i n e s w h e t h e r o n s h o r e move-ment o f s and o c c u r s o r n o t : At P r o f i Ies D and E, t h e b r e a k e r h e i g h t s a r e g r e a t e r t h a n 3 f e e t ( T a b l e X ) , and as a r e s u l t , s and i s e r o d e d f r o m t h e u p p e r f o r e s h o r e and t r a n s p o r t e d s e a -wards t o t h e r i d g e s . At P r o f i l e s A , G and B, C , F, t h e b r e a k e r h e i g h t s a r e l e s s t h a n 3 f e e t ( T a b l e X ) , and sand i s t r a n s -p o r t e d l a n d w a r d s t o t h e u p p e r f o r e s h o r e . The v i c i n i t y o f t h e w a t e r t a b l e l i n e o f e m e r g e n c e b e h a v e s I i k e a n o d a l z o n e w i t h r e s p e c t t o f o r e s h o r e p r o f i l e c h a n g e s , i . e . t h e m a g n i t u d e o f a c c r e t i o n o r e r o s i o n i s l e a s t h e r e . At P r o f i l e s D and E, b e a c h r i d g e s were b u i l t i m m e d i a t e -l y s e a w a r d o f t h e s e z o n e s , and e r o s i o n p r o g r e s s e d i m m e d i a t e l y l a n d w a r d o f them ( F i g u r e s 20b and 2 2 b ) . At P r o f i l e s A and G, e r o s i o n o c c u r r e d s e a w a r d o f t h e n o d a l z o n e s , and b e r m - b u i I d i n g p r o g r e s s e d i m m e d i a t e l y l a n d w a r d o f them ( F i g u r e s \kb and 2 6 b ) . At P r o f i l e B, s and was t r a n s p o r t e d r a p i d l y a c r o s s t h i s z o n e i n a l a n d w a r d o r s e a w a r d d i r e c t i o n , d e p e n d i n g on t i d a l r ange ( F i g u r e 17) . At P r o f i l e C , t h e m a g n i t u d e o f a c c r e t i o n was much l e s s l a n d w a r d o f t h i s z o n e , t h a n i t was i m m e d i a t e l y s e a w a r d o f t h e z o n e ( F i g u r e 18b ) . At P r o f i l e F, t h e b e a c h s l o p e d i p p e d g e n t l y s e a w a r d s , and t h e l i n e o f w a t e r t a b l e e m e r g e n c e was t h e r e f o r e no t s t a t i c ; c o n t i n u a l , u n i f o r m a c c r e t i o n was t h e r e s u l t ( F i g u r e 2 5 ) . In summary t h e n , f o r e s h o r e c h a n g e s d i c t a t e d * See GLOSSARY 117. by summer wave c o n d i t i o n s a r e c o n t r o l l e d by t h e p r e s e n c e and p e r m a n e n c e o f t h e w a t e r t a b l e l i n e o f e m e r g e n c e . I m p l e m e n t a t i o n o f B a s c o m ' s (1951) " r e f e r e n c e l e v e l " f o r c o r r e l a t i n g f o r e s h o r e s l o p e w i t h s and s i z e , was m o d e r a t e l y s u c c e s s f u l a t Wreck Bay , A f a i r l y w i d e r ange o f f o r e s h o r e s l o p e s , 0.8° t o 2.6°, i s i n d i c a t e d f o r v e r y f i n e sand a t t h e m i d - w a t e r l e v e l on t h e 2 6 t h J u l y 1968 ( F i g u r e s 14a, 16a, 18a, 2 0 a , 2 2 a , 2 4 a , 2 6 a ) . H o w e v e r , e x c l u s i o n o f t h e P r o f i l e D s l o p e , where r i d g e b u i l d i n g was i n p r o g r e s s a t t h e t i m e , r e d u c e s t h i s r ange t o 0.8° t o 1.4°. I n c o m p l e t e p r o f i l e m e a s u r e m e n t s i n w i n t e r p r o h i b i t e d s i m i l a r c o m p a r i s o n s f o r t h i s p e r i o d , h o w e v e r , t h e f o r e s h o r e s l o p e s were g e n e r a l l y l e s s s t e e p and c o n s i d e r a b l y c o a r s e r g r a i n e d ( F i g u r e s 14a, 16a, 18a, 2 0 a , 2 2 a , 2 4 a , 26a). T a b l e IX i s a l i s t i n g o f maximum p r o f i l e c h a n g e s w i t n e s s e d d u r i n g t h e summer, and o t h e r p e r t i n e n t b e a c h d a t a . I 18. P r o f i Ie M a x . a c c r e l * : i on Max. e r o s i o n Berm e l e v a t i o n ( f e e t ) W a t e r t a b l e e 1 e v a t i on ( f e e t ) Summer Da te Rod No F e e t D a t e Rod No F e e t W i n t e r Summer A 22 Aug? 2 0 , 3 9 29 Aug? 2 1.08 12,5 12.5 8.5 B 22 Aug? 6 l „ 4 4 29 Aug? 6 1. 20 13.0 1 1,0 8 .5 C I 7 Aug , 4 1,38 3 J u l y 3 1. 15 25 ,5 - 9 , 0 D II Au g o 4 2.47 30 Ju 1 y 2 2,73 20,5 - 1 1.0 E I I Aug . 4 2,02 1 1 Aug, 6 1. 16 19,0 - 10,0 F I 7 Aug , 6 2 ,00 5 Aug , 1 0 . 5 2 - 15.5 12.0 G 28 Aug? 2 2.41 22 Aug. $ 5 0 . 9 9 15.5 17.0 13,5 * R e l a t i v e t o t h e day o f p r o f i l e emp lacement i n J u n e , u n t i l t h e end o f A u g u s t 1968. $ A f t e r t h e summer s t o r m on ! 8 t h A u g u s t , 1 9 6 8 . Tab 1e IX. Maximum A c c r e t i o n and E r o s i o n V a l u e s a t e a c h P r o f i l e d u r i n g t h e Summer. W i n t e r B e r m , Summer Berm and W a t e r T a b l e E l e v a t i o n s a r e a l s o shown. I t i s a p p a r e n t t h a t a c c r e t i o n v a l u e s were h i g h e r f o r t h e s o u t h e a s t p a r t o f t h e b e a c h ( P r o f i l e s D. E, F and G) r e l a -t i v e t o t h e n o r t h w e s t p a r t ( P r o f i l e s A , B and C ) . C o n v e r s e l y , e r o s i o n v a l u e s were l e s s f o r t h e s o u t h e a s t p a r t o f t h e b e a c h , ( P r o f i l e s E, F and G) r e l a t i v e t o t h e n o r t h w e s t p a r t ( P r o f i l e s A , B, C and D ) , T h e s e two o b s e r v a t i o n s s u g g e s t t h a t t h e m a g n i -t u d e o f a c c r e t i o n d u r i n g summer i s g r e a t e s t on t h e s o u t h e a s t p a r t o f t h e b e a c h . E x a m i n a t i o n o f a e r i a l p h o t o g r a p h s i n d i c a t e t h a t s w e l l e n t e r i n g t h e s o u t h e a s t p o r t i o n o f t h e bay has a d i f f e r e n t f o rm to i t s c o u n t e r p a r t i n t h e n o r t h w e s t , t h i s b e i n g p r i m a r i l y due t o d i f f r a c t i o n a r o u n d F l o r e n c i a I s l a n d , In t h e I 19. s o u t h e a s t p o r t i o n o f t h e bay s w e l l a p p e a r s t o h a v e a s h a r p c r e s t , and g e n e r a t e s 2 - 3 rows o f b r e a k e r s on t h e b e a c h ; i n t h e n o r t h w e s t , s w e l l has a r o u n d e d f o r m , and g e n e r a t e s 4 - 5 rows o f b r e a k e r s on t h e b e a c h ( s e e F r o n t i s p i e c e and F i g u r e 2 ) . Waves a f f e c t i n g t h e s o u t h e a s t p a r t o f t h e b e a c h t h e r e f o r e , a p p e a r t o have l o s t a l a r g e p o r t i o n o f t h e i r t o t a l e n e r g y i n t h e p r o c e s s o f b e i n g d i f f r a c t e d , and a r e i n a l l p r o b a b i l i t y r e s p o n s i b l e f o r t h e g r e a t e r m a g n i t u d e o f a c c r e t i o n t h e r e r e l a -t i v e t o t h e n o r t h w e s t p a r t . P r o f i l e D, l o c a t e d i n t h e m i d d l e o f t h e b e a c h a d j a -c e n t t o Sand P o i n t , i s e x p o s e d t o waves w h i c h have b e e n o n l y s l i g h t l y a f f e c t e d by r e f r a c t i o n a c r o s s t h e s h o a l i n g b a y . T h i s p r o f i l e e x p e r i e n c e d b o t h t h e g r e a t e s t amount o f a c c r e t i o n and e r o s i o n d u r i n g t h e summer ( T a b l e I X ) , i n d i c a t i n g t h a t i t r e -p r e s e n t s t h e most a c t i v e h y d r o d y n a m i c e n v i r o n m e n t on t h e b e a c h . P r o f i l e s A and G, l o c a t e d i n t h e l e e o f Q u i s i t i s P o i n t and Wya P o i n t r e s p e c t i v e l y , e x p e r i e n c e d maximum a c c r e -t i o n on t h e u p p e r f o r e s h o r e due t o berm b u i l d i n g ( r o d s # 2 ) . P r o f i l e s D and E, on e i t h e r s i d e o f Sand P o i n t , e x p e r i e n c e d maximum a c c r e t i o n on t h e m i d - f o r e s h o r e due t o r i d g e b u i l d i n g ( r o d s #4), and P r o f i l e s B, C and F e x p e r i e n c e d maximum a c c r e -t i o n on t h e l ower and m i d - f o r e s h o r e ( r o d s #6 and 4). I t i s i n t e r e s t i n g t o n o t e t h a t t h e e q u i l i b r i u m p r o -f i l e s l o c a t e d i n s e m i - p r o t e c t e d a r e a s o f t h e b e a c h , P r o f i l e s A, I 20 , B and G were a l l most s e v e r e l y a f f e c t e d by t h e summer s t o r m . The o t h e r p r o f i l e s a t t a i n e d t h e i r maximum a c c r e t i o n and e r o -s i o n v a l u e s p r i o r t o t h e s t o r m ( T a b l e I X ) . W i t h r e s p e c t t o w a t e r t a b l e and summer berm e l e v a -t i o n s , i t w i l l be s e e n t h a t t h e f o r m e r i s h i g h e r i n t h e s o u t h -e a s t p a r t o f t h e b e a c h , and t h a t summer berms a r e e s t a b l i s h e d f r om 2 r 5 - 4 „ 0 f e e t a b o v e i t . W i n t e r berm e l e v a t i o n s have no r e l a t i o n t o t h e w a t e r t a b i e e l e v a t i o n s , b e i n g d i c t a t e d m a i n l y by b r e a k e r h e i g h t s i n e a c h a r e a . Be tween P r o f i l e C and t h e s p i t b a r (Map I ) , 4 d i s t i n c t g r a v e l berms e x i s t e d on t h e b a c k -s h o r e , t h e most e x t e n s i v e o n e b e i n g a t 25 .5 f e e t , w h i c h was a l s o t h e h i g h e s t w i t h i n Wreck Bay ( T a b l e I X ) . B a s e d on model t a n k s t u d i e s ( B a g n o l d , 1 9 4 0 ) , t h e h e i g h t o f a berm a b o v e s e a l e v e l i s 1,3 t i m e s t h e h e i g h t o f deep w a t e r waves w h i c h f o rmed i t , t h u s g i v i n g an a p p r o x i m a t e a m p l i t u d e o f 19 f e e t f o r t h e waves w h i c h f o r m e d t h i s be rm. B a s e d on t h e o b s e r v a t i o n s made i n F e b r u a r y 1969, i t i s b e l i e v e d t h a t v i o l e n t w i n t e r s t o r m waves a r e not r e s p o n s i b l e f o r berm b u i l d i n g a l o n g t h e b a c k s h o r e , b u t a c t u a l l y d e s t r o y any t h a t happen t o e x i s t t h e r e a t t h e t i m e . R e l a t i v e l y l e s s v i o l e n t s p r i n g s t o r m waves a r e t h o u g h t t o be t h e a g e n t p r o d u c i n g t h e s e h i g h berms ( s e e c h a p t e r on SEDIMENT S I Z E A N A L Y S I S ) , and t h e r e f o r e wave h e i g h t s i n e x c e s s o f 19 f e e t must o c c u r a t Wreck Bay d u r i n g w i n t e r s t o r m s . E. PROF ILE CHANGES T H K O U G H ONE T IDAL CYCLE P r o f i l e s B, C and D were m e a s u r e d a t h a l f - h o u r l y 121. i n t e r v a l s i n c o n j u n c t i o n w i t h t r a c e r d i s p e r s i o n e x p e r i m e n t s c o n d u c t e d a t t h e s e l o c a t i o n s ( s e e c h a p t e r on SAND MOVEMENT BASED ON TRACER D ISPERS ION) . I. GROSS CHANGES E x a m i n a t i o n o f F i g u r e s 29 , 3 0 , 3 1 , i n d i c a t e t h a t a s m a l l amount o f a c c r e t i o n o c c u r s as t h e f i r s t swashes wash o v e r t h e f o r e s h o r e w i t h r i s i n g t i d e l e v e l - a p o i n t n o t i c e d by S t r a h l e r (1964) i n a s i m i l a r s e t o f e x p e r i m e n t s . H o w e v e r , t h i s a c c r e t i o n s t a g e i s s h o r t - l i v e d , s i n c e c l o s e b e h i n d t h e swash z o n e , e r o s i o n becomes t h e d o m i n a n t p r o c e s s i n t h e b a c k -wash z o n e . As t h e s e z o n e s a d v a n c e l a n d w a r d w i t h f l o o d t i d e , m a t e r i a l i n i t i a l l y d e p o s i t e d by t h e s w a s h , t o g e t h e r w i t h some o r i g i n a l s e d i m e n t , i s t h e n s c o u r e d o u t a n d t r a n s p o r t e d s e a w a r d t o t h e b r e a k e r zone s t e p b y - t h e b a c k w a s h . D u r i n g ebb t i d e , t h e r e v e r s e s e q u e n c e o c c u r s , i . e . t h e b r e a k e r z o n e s t e p i s e r o d e d by r e t r e a t i n g b a c k w a s h , and t h e l a s t z o n e t o i n f l u e n c e t h e b e a c h s u r f a c e , t h e swash , c o m p l e t e l y r e s t o r e s t h e f o r e s h o r e p r o f i l e b a c k t o i t s e q u i l i b r i u m . ' s h a p e . I n i t i a l swash a c c r e t i o n a t P r o f i l e s B and C ( F i g u r e s 29 and 30) i s g r e a t e r above t h e w a t e r t a b l e l i n e o f e m e r g e n c e , t h a n b e l o w i t . The r e a s o n f o r t h i s i s t h a t some o f t h e swash w a t e r s i n k s i n t o d r y s and a b o v e t h e w a t e r t a b l e , and i t s s e d i -ment l o a d i s d e p o s i t e d . B e l o w t h e w a t e r t a b l e l i n e o f e m e r g e n c e h o w e v e r , t h e swash w a t e r a l l r e t u r n s s e a w a r d as b a c k w a s h , and a p o r t i o n o f t h e s e d i m e n t l o a d i s t r a n s p o r t e d w i t h i t ( G r a n t , 1948) . * S e e GLOSSARY 122. A d v a n c e and r e t r e a t o f t h e b r e a k e r z o n e s t e p t h r o u g h t h e t i d a ! c y c l e i s c l e a r l y e v i d e n t a t P r o f i l e B ( F i g u r e 2 9 ) , b u t a t P r o f i l e C ( F i g u r e 3 0 ) , t h i s phenomenon i s o n l y a p p a r e n t i n t h e v i c i n i t y o f t h e w a t e r t a b l e . At P r o f i l e D ( F i g u r e 3 1 ) , c o n t i n u o u s h a l f - h o u r l y m e a s u r e m e n t s a t h i g h t i d e were not p o s s i b l e , b e c a u s e o f h i g h waves w h i c h a f f e c t e d t h e a r e a . C a r e f u l e x a m i n a t i o n o f F i g u r e s 2 9 , 30 and 31 i n d i -c a t e t h a t a n a r r o w z o n e o f 15 - 25 f e e t , l o c a t e d i m m e d i a t e l y l a n d w a r d o f t h e w a t e r t a b l e l i n e o f e m e r g e n c e , s u f f e r s more i n t e n s i v e backwash e r o s i o n d u r i n g ebb t i d e t h a n i t does d u r i n g f l o o d t i d e . T h i s i s p r o b a b l y t h e r e s u l t o f a I - 3 h o u r t i m e l a g b e t w e e n t h e t i d e and w a t e r t a b l e p e r i o d s (Emery and F o s t e r , 1948 ) . A h i g h e r w a t e r t a b l e d u r i n g ebb t i d e w o u l d e n h a n c e e l u t r i a t i o n o f f i n e m a t e r i a l f r o m t h i s z o n e , t h e r e b y a c c o u n t -i n g f o r i t s i n c r e a s e d e r o s i o n . F i g u r e 29. Changes at P r o f i l e B through one t i d a l c y c l e . - C i r c l e d numerals on the diagram denote p r ima -ry rod numbers; smal l l e t t e r s between them denote secondary rod numbers. The l a t t e r were emplaced at low t i d e on the 9th August 1968, the day t r a c e r d i s p e r s i o n exper iments were conducted on the f o r e s h o r e , and were spaced 5 f e e t a p a r t . - The p r o f i l e was measured at h a l f - h o u r l y i n t e r -v a l s , and f o r e s h o r e e l e v a t i o n changes were expressed r e l a t i v e to the p r o f i l e at t ime o f secondary rod emplacement. - F i gu re s 30 and 31 are s i m i l a r p r e s e n t a t i o n s o f P r o f i l e s C and D r e s p e c t i v e l y . P R O F I L E (D , 1 2 3 MID-TIDE HW MID-TIDE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 TIME IN HALF HOUR UNITS FIGURE 29 P r o f i Ie c h a n g e s t h r o u g h one t i d a l c y c l e i—i—i—r~r HW 2k "i—i—r a o -o a i—i—i—i—r j—i—i—r g © e h o -< I o C o — "XX. r— \ / \ \ / \ x ' . \ V ^ \ / \ V r ~~\ \ / \ v C o o f — — \ g c <r- " h o *• — " ° * I I e o - o — - o 5 s r~ I 1 1 III 1 I g h - — o I — o f —• 3 —» c ~« f o ) 5 6 7 8 9 10 11 12 13 14 15 16 17 T I M E IN HALF HOUR UNITS F I G U R E 3 0 P r o f i l e c h a n g e s t h r o u g h o n e t i d a l c y c l e P R O H L E {Q) i—i—i—i—i i I i—r i i r o » — h o t o h b 0 C c » ' ' e t>- o t »- -g <--I O -O , d o o-~ ~ Z 0 o i 0 — g o — b o- o C o o- -<J o or" J— - o - — - o o b * -o b --o C . M i l ^ °. d *> - ° , f o-h « r - - - o 0 g e--i—9''--c-6!r;'__0_.--g=- = =8--l--<>" aY-'--IT;'.> = » b d o 0 g o— —o( 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1« 17 18 19 20 TIME IN HALF HOUR UNITS F I G U R E 31 P r o f i I e , c h a n g e s t h r o u g h o n e t i d a l c y c l e 126. 2. NET CHANGES E x t r e m e v e r t i c a l e x a g g e r a t i o n o f t h e s e d i a g r a m s (100 X ) , and c l o s e s p a c i n g o f t h e p r o f i l e r o d s , i l l u s t r a t e s t h a t e r o s i o n does i n f a c t o c c u r a t P r o f i l e s B and C. T h i s was no t a p p a r e n t i n t h e l o n g - t e r m m e a s u r e m e n t s o f P r o f i l e C, p r o b -a b l y b e c a u s e t h e d a y - t o - d a y c h a n g e s i n t i d a l r ange r e s u l t e d i n a c c r e t i o n a t d i f f e r e n t p l a c e s on t h e f o r e s h o r e , t h e r e b y g i v i n g t h e i m p r e s s i o n o f o v e r - a l l a c c r e t i o n . Berm b u i l d i n g a t P r o f i l e s B and C and r i d g e b u i l d i n g a t P r o f i l e D a r e , h o w e v e r , c l e a r l y e v i d e n t . The two p e a k s on P r o f i l e D r i d g e a r e most l i k e l y t h e r e s u l t o f e r o s i o n on e i t h e r s i d e o f t h e r i d g e - on t h e u p p e r and l ower f o r e s h o r e . The most d r a m a t i c e v e n t d i s p l a y e d by t h e s e d i a g r a m s i s t h e a p p a r e n t c o n f i n e m e n t o f e r o s i o n be tween t h e w a t e r t a b l e and t h e h i g h t i d e mark . W i t h P r o f i l e C, i t w i l l be s een t h a t t h e s p a t i a l r e l a t i o n s h i p be tween t h e s e marks i s r e v e r s e d r e l a -t i v e t o P r o f i l e s B and D, and y e t t h e same p a t t e r n o c c u r s . T h i s phenomenon must be a r e s u l t o f d i f f e r e n t i a l f o r e s h o r e e r o s i o n above and b e l o w t h e w a t e r l i n e o f e m e r g e n c e ( G r a n t , 1948) as s een a t P r o f i l e C , and a l s o b e c a u s e a h i g h e r w a t e r t a b l e e l e v a t i o n d u r i n g ebb t i d e e n h a n c e s e r o s i o n i m m e d i a t e l y l a n d w a r d o f i t (Emery a n d F o s t e r , 1948) as s e e n a t P r o f i l e s B and D. F i g u r e 32 , Net c h a n g e s a t P r o f i l e s B, C and D a f t e r o n e t i da I eye Ie, - C i r c l e d n u m e r a l s a l o n g t h e b o t t o m o f e a c h p r o -f i l e d i a g r a m d e n o t e p r i m a r y rod number s ; s m a l l l e t t e r s be tween them d e n o t e s e c o n d a r y r o d s . - B o t h axe s o f t h e d i a g r a m s a r e g r a d u a t e d i n f e e t , and v e r t i c a l e x a g g e r a t i o n i s 100 X, - The p r o f i l e s a r e p l o t t e d as s t r a i g h t l i n e s f o r t h e f o r e s h o r e e l e v a t i o n s a t low t i d e p r e c e e d i n g t h e t r a c e r d i s p e r s i o n e x p e r i m e n t s . The c u r v e d l i n e s r e p r e s e n t ne t p r o f i l e c h a n g e s i n c u r r e d a f t e r o n e t i d a l c y c l e . They were d e r i v e d f r om F i g u r e s 2 9 , 30 and 31 by s u b t r a c t i n g t h e s and e l e v a t i o n s a t e a c h rod s t a t i o n on t h e r i g h t -hand s i d e o f t h e d i a g r a m s , f r om t h o s e on t h e l e f t - h a n d s i d e . - P o s i t i o n o f t h e l i n e o f e m e r g e n c e o f t h e w a t e r t a b l e , and t h e h i g h t i d e mark a r e shown on t o p o f t h e d i a g r a m s . - P o s i t i o n o f t h e s and t r a c e r s a m p l i n g g r i d s a r e i n d i c a t e d f o r e a c h p r o f i l e , and t h e a r e a o f g r a v e l t r a c e r d i s p e r s i o n i s shown f o r P r o f i Ie D. F I G U R E 32 • t>2 • O l Hinh t i d e Net p r o f i l e c h a n g e s a f t e r o n e t i d a l c y c l e W a t e r t a b l e - O l - 0 2 0 a b c d © a b c d e f g h i © a b c d e f g h i © P R O F I L E (B) -•02 . O l W a t e r t a b l e ~\> o o~ -LU 6 \E F - P R O F H igh t i d e I L E G R I D LxJ ^-01 -02 v--b c © a b c d e f g h i © a b c d e f g h i © a b c d e f g h i j © P R O F I L E O -•02 •Ol o -01 -02 \ /•..., H i g h t i d e U P P E R G R I D r V P E B B L E / C O B B L E C O N C E N T R A T I O N W a t e r t a b l e L O W E R / G R I D " P R O F I L E a © a b c d e © a b c d e f g h i © a b c d e f © a b c d e f g 1 I I 1 1 1 I I I I 1 I I 1 I J I _ L S O I O O I S O F E E T 200 2 5 0 -128. P l a t e 10, P r o c e d u r e u s e d f o r m e a s u r i n g s and e l e v a t i o n c h a n g e s d u r i n g t h e summer. G r a d u a t e d s t a f f , w i t h f l a t b a s e , i s p l a c e d a d j a c e n t t o t h e p r o f i l e r o d , and t h e e l e v a t i o n o f i t s t i p above t h e s and s u r f a c e i s m e a s u r e d . 129. PI a t e I 1 a . Mouth o f L o s t Shoe C r e e k on 3 0 t h J u n e 1968. P l a t e 1 l b . Mouth o f L o s t Shoe C r e e k on 3 1 s t J u l y 1968. N o t e t h e t h i c k l a y e r o f s and ( I . I f e e t ) above b o u l d e r s i n t h e s t r e a m b e d . 130. V I I I . SAND MOVEMENT BASED ON WAVE PARAMETERS A. INTRODUCTION The wave p a t t e r n i n Wreck Bay i s a c o m p l e x o n e ( F i g u r e 2 ) , and e v a l u a t i o n o f s and movement a l o n g t he s h o r e b a s e d on wave p a r a m e t e r s , c a n o n l y be s e m i - q u a n t i t a t i v e i n v a l u e . H o w e v e r , t h e p u r p o s e o f t h e i n v e s t i g a t i o n was s i m p l y to g a i n an i m p r e s s i o n o f l i t t o r a l d r i f t a l o n g t h e b e a c h , d u r i n g a t y p i c a l summer r e g i m e . Wave g e n e r a t e d l i t t o r a l c u r r e n t s a r e u s u a l l y t o o weak t o t r a n s p o r t b e a c h m a t e r i a l t h e m s e l v e s , b u t t u r b u l e n c e c r e a t e d by b r e a k i n g waves c a n s e t a l l b u t c o b b l e s and b o u l d e r s i n t o a s t a t e o f s e m i - s u s p e n s i o n ; t h e p a r t i c l e s t h e n move by r o l l i n g a l o n g t h e f o r e s h o r e and s a l t a t i o n rn t h e n e a r s h o r e z o n e ( B a s c o m , 1964 ) . As a r e s u l t o f t h i s , a p p r o x i m a t e Iy 80% o f l i t t o r a l d r i f t o c c u r s w i t h i n a n a r r o w z o n e l y i n g be tween t h e b r e a k e r z o n e and t h e b e a c h ( J o h n s o n , 1956 ) . A method d e v i s e d by C a l d w e l l ( 1956) f o r d e t e r m i n i n g l i t t o r a l d r i f t has been c l o s e l y f o l l o w e d i n t h i s s t u d y . The t e c h n i q u e i n v o l v e s wave p a r a m e t e r measurement c l o s e t o s h o r e , and t h u s t a k e s i n t o a c c o u n t t h e s p a t i a l v a r i a b i l i t y o f waves i n a c o m p l e x h y d r o d y n a m i c e n v i r o n m e n t such as a t Wreck Bay . B. WAVE PARAMETERS V i s u a l e s t i m a t e s o f wave p a r a m e t e r s were made e a c h t i m e t h e p r o f i l e s were m e a s u r e d ( s e e c h a p t e r on TRANSVERSE PRO F I L E S ) , and i n c l u d e d t h e h e i g h t , a p p r o a c h a n g l e , and p e r i o d o f b r e a k e r s a f f e c t i n g t h e d i f f e r e n t l o c a t i o n s . A number o f 131. b r e a k e r he ight , m e a s u r e m e n t s - e r e a l s o made u s i n g g r a d u a t e d p o l e s , w h i c h were e m p l a c e d on t h e lower f o r e s h o r e i n m i d - J u l y 1968. The a v e r a g e i n c i d e n t a n g l e o f b r e a k e r s a t t h e d i f f e r e n t p r o f i l e l o c a t i o n s were a l s o d e t e r m i n e d by e x a m i n i n g s i x s e t s o f a e r i a ! p h o t o g r a p h s and t h e s e f i g u r e s c o r r e s p o n d e d v e r y w e l l w i t h t h e f i e l d e s t i m a t e s { T a b l e i l l ) . B r e a k e r p e r i o d s were m e a s u r e d by c o u n t i n g t h e number t o p a s s a p r o f i l e r o d i n o n e mi nu t e , A summary o f p a r a m e t e r s u s e d i n t h e c a l c u l a t i o n s a r e shown i n T a b l e X, The s i g n i f i c a n t b r e a k e r h e i g h t i s t h e a v e r a g e o f t h e h i g h e s t 1/3 o f a l l b r e a k e r h e i g h t s m e a s u r e d , and t h e s i g n i f i c a n t b r e a k e r p e r i o d i s t h e a v e r a g e o f p e r i o d s a s s o c i a -t e d w i t h t h e s i g n i f i c a n t b r e a k e r s . P r o f i Ie S i g n i f i c a n t b r e a k e r h e i g h t ( f e e t ) S i g n i f i c a n t b r e a k e r p e r i o d ( s e c o n d s ) B r e a k e r i n c i d e n t a n g l e ( d e g r e e s ) * A .75 10 - 7 B 2 .50 10 - 2 C 2,75 10 1 D 4 . 0 0 10 - 4 E 3 .50 10 3 F 2 .50 10 - 1 G 1 .00 10 6 * - s i g n i n d i c a t e s a s o u t h e a s t d i r e c t i o n , no s i g n i n d i c a t e s a n o r t h w e s t d i r e c t i o n . Tab Ie X. Summary o f Wave P a r a m e t e r s u s e d i n L i t t o r a l D r i f t C a l c u l a t i o n s . I32v C. LITTORAL ZONE The z o n e i n w h i c h most o f t h e l i t t o r a l d r i f t o c c u r s , d e p e n d s on t h e w a t e r d e p t h a t w h i c h waves b r e a k , Emery (I960) s t a t e s t h a t t h i s d e p t h i s a p p r o x i m a t e l y k/3 t h e wave h e i g h t ; t h e y b r e a k when w a t e r p a r t i c l e s a r e u n a b l e t o c o m p l e t e f u l l c i r c u l a r o r b i t s due t o b o t t o m f r i c t i o n . p r o f i l e was s u f f i c i e n t l y w i d e , w a t e r d e p t h s were s e t a t t w i c e t h e s i g n i f i c a n t b r e a k e r h e i g h t ( T a b l e X I ) . The z o n e w i d t h s t h u s e x t e n d e d f r o m j u s t s e a w a r d o f t h e b r e a k e r z o n e s t o t h e u p p e r l i m i t s o f swash a c t i v i t y . p a r a m e t e r s w e re made a t a b o u t t h e m i d - t i d e l e v e l . I t was t h e r e -f o r e d e c i d e d t o b a s e t h e c a l c u l a t i o n s on a t i m e i n t e r v a l o f o n e h o u r . T h i s was c o n s i d e r e d s a t i s f a c t o r y t o p r o v i d e s e m i -q u a n t i t a t i v e e s t i m a t e s on t h e d i r e c t i o n a nd i n t e n s i t y o f l i t -t o r a l d r i f t a t t h e d i f f e r e n t l o c a t i o n s , D. CALCULATIONS To e n s u r e t h a t t h e l i t t o r a l z o n e c o n s i d e r e d a t e a c h F i n a l l y , most o f t h e f i e l d m e a s u r e m e n t s on wave I. SHALLOW WATER WAVE LENGTH The c l a s s i c a l e q u a t i o n o f h y d r o d y n a m i c s s t a t e s : c 2 = | L t a n h 2 i d 2M L . ( I ) w h e re c wave v e l o c i t y 9 g r a v i t a t i o n a l a c c e l e r a t i o n L = wave l e n g t h d = w a t e r d e p t h 133. F o r s h a l l o w w a t e r c o n d i t i o n s , d becomes s m a l l c o m p a r e d t o L, and t a n h ~ - t e n d s t o ™ - ( I n m a n , i n S h e p a r d , 1963 ) . T h e r e -f o r e The v e l o c i t y o f waves i n w a t e r o f any d e p t h i s g i v e n by C = /j where T i s t h e p e r i o d , and by s u b s t i t u t i n g t h i s i n t o e q u a t i o n ( 2 ) , t h e wave l e n g t h c a n be f o u n d i n t e rms o f t h e p e r i o d and w a t e r d e p t h : L = Ts/gd . . . ( 3 ) 2. TOTAL FORWARD MOVING WAVE ENERGY The t o t a l e n e r g y p e r u n i t l e n g t h o f a s i n g l e wave i s a p p r o x i m a t e l y g i v e n by t h e f o l l o w i n g r e l a t i o n ( C a l d w e l l , 1956) : 2 2 2iid £ = HIT H t a n h -j-- (4) where H i s t h e b r e a k e r h e i g h t i n f e e t , and t h e o t h e r q u a n t i t i e s a r e a l s o i n f . p . s . u n i t s . A m a j o r p o r t i o n o f t h i s t o t a l e n e r g y t r a v e l s f o r w a r d w i t h t h e wave f o r m . The t o t a l f o r w a r d m o v i n g e n e r g y o f a wave t r a i n c a n be f o u n d f o r s h a l l o w w a t e r c o n d i -t i o n s , by mu 11 i p I y i r.g £ by Vj where t h i s t h e s e l e c t e d i n t e r -v a l o f t i m e : E = 4 l T H 2 ( t a n h - ~ ) t (5) bu t s i n c e t a n h ^iid t e n d s t o ^ ™ i n s h a l l o w w a t e r , t h e e q u a t ; o p r e d u c e s t o : 2 E = 2 5 7 . 7 (6) 3. ALONGSHORE ENERGY COMPONENT The a n g l e b e t w e e n b r e a k i n g waves and t h e b e a c h 134. d e t e r m i n e s t h e d i r e c t i o n and s t r e n g t h o f t h e a l o n g s h o r e compo-nent o f t h e tota l f o r w a r d m o v i n g wave e n e r g y . T h i s i s d e t e r -m i n e d f r o m t h e r e l a t i o n s h i p ( C a l d w e l l , 1956 ) : e = E s i nOcosQ (7) 2 t h a t i s , = 2 5 7 . 7 ( I t p L £ ) s i n Q c o s 0 (8) where e = t o t a l a l o n g s h o r e e n e r g y i n f o o t - p o u n d s 0 = a n g l e o f i n c i d e n c e o f b r e a k e r s 4. L ITTORAL DKIFT S t u d i e s made by t h e B e a c h E r o s i o n B o a r d (1952) i n F l o r i d a , and by C a l d w e l l (1956) i n C a l i f o r n i a , l e d t o an e m p i r i c a l r e l a t i o n s h i p b e t w e e n t h e amount o f l i t t o r a l d r i f t and t h e a l o n g s h o r e wave e n e r g y : Q = k e 0 * 8 . . ( 9 ) w h e r e 0 = a l o n g s h o r e s and movement i n c u b i c y a r d s e = a l o n g s h o r e wave e n e r g y i n m i l l i o n s o f f o o t - p o u n d s p e r f o o t o f b e a c h p e r h o u r k = p r o p o r t i o n a l i t y f a c t o r ( t e n t a t i v e l y 210) w h i c h g i v e s t h e f i n a l e q u a t i o n u s e d i n t h i s s t u d y : Q = 2 l 0 J 2 5 7 . 7 ( - ~ ^ ) s i n e c o s e | ' (10) I t s h o u l d be p o i n t e d o u t t h a t e q u a t i o n (9 ) d e v e l o p e d by t h e two s t u d i e s m e n t i o n e d a b o v e , was d e t e r m i n e d on b e a c h m a t e r i a l w i t h m e d i a n d i a m e t e r o f a b o u t 0 .4 mm. At Wreck Bay t h e s and i s much f i n e r w i t h a v e r a g e m e d i a n o f 0 .15 mm; t h e r e s u l t s o b t a i n e d i n t h e p r e s e n t s t u d y s h o u l d t h e r e f o r e be c o n -s i d e r e d as minimum v a l u e s . 135, E. RESULTS The r e s u l t s a r e i n d i c a t e d i n t a b u l a r f o r m : P r o -f i Ie W a t e r d e p t h ( f e e t ) Sha11ow Wate r wave 1 e n g t ( f e e t ) T o t a l f o r w a r d m o v i n g wave e n e r g y ( f o o t - p o u n d s / h o u r / f o o t o f b e a c h ) T o t a l a l o n g -s h o r e e n e r g y ( f o o t - p o u n d s / h o u r / f o o t o f b e a c h ) * L i t t o r a l d r l f t ( c u b . y d s . / h o u r ) * A 1.5 49 161,400 - 1 9 , 5 3 0 - 9 . 0 B 5.0 89 3 , 2 7 3 , 0 0 0 - 1 1 4 , 1 0 0 - 3 7 . 0 C 5.5 93 4 , 155,000 7 2 , 4 9 0 25 .7 D 8 . 0 1 12 1 0 , 6 0 0 , 0 0 0 - 7 3 7 , 9 0 0 - 1 6 4 , 6 E 7.0 105 7 , 5 9 5 , 0 0 0 3 9 6 , 9 0 0 100.2 F 5 .0 89 3 , 2 7 3 , 0 0 0 - 5 7 , 1 2 0 - 2 1 . 3 G 2.0 56 331 ,300 3 4 , 4 3 0 14.2 * - s i g n i n d i c a t e s a s o u t h e a s t d i r e c t i o n , no s i g n i n d i c a t e s a n o r t h w e s t d i r e c t i o n . Tab Ie XI . L i t t o r a l D r i f t a t P r o f i l e s A t o G D u r i n g t h e Summer Reg ime. F. DISCUSSION A d j a c e n t t o t h e two h e a d l a n d s , l i t t o r a l d r i f t a t P r o f i l e s A and G was a l w a y s u n i d i r e c t i o n a l , . The a n g l e s o f wave i n c i d e n c e a t b o t h l o c a t i o n s were l a r g e , bu t t h e waves t h e m s e l v e s were s m a l l , t h u s r e s u l t i n g i n v e r y l i t t l e s and movement. A d j a c e n t t o Sand P o i n t , P r o f i l e s D and E were a f f e c t -ed by u n i f o r m l i t t o r a l c u r r e n t s f o r most o f t h e t i m e , bu t t h e s e were a l w a y s c o m p l i c a t e d by s m a l l wave t r a i n s r e s u l t i n g f r o m 136. d i f f r a c t i o n a r o u n d S e a l Rock and F l o r e n c i a I s l a n d ( s e e c h a p t e r on PLANIMETRIC S H A P E ) , and a t P r o f i l e D, by r e f r a c t i o n on t h e l o n g s h o r e b a r a t c e r t a i n t i d e l e v e l s ( s e e c h a p ' . e r on SAND MOVE-MENT BASED ON TRACEK DI S P E K S 1 ON),. F u r t h e r m o r e , w i n d - b l o w n s t o r m waves f r o m t h e s o u t h o c c a s i o n a l l y r e v e r s e t h e p r e v a i l i n g l i t t o -r a l c u r r e n t d i r e c t i o n s a r o u n d t h e w h o l e bay ( T a b l e I I I ) . How-e v e r , a l t h o u g h t h e a v e r a g e i n c i d e n t a n g l e o f waves d u r i n g t h e summer i s s m a l l e r a t t h e s e two l o c a t i o n s t h a n a t P r o f i l e A and G, t h e wave h e i g h t s a r e much l a r g e r , r e s u l t i n g i n c o n s i d e r a b l e v o l u m e s o f s a n d movement . The s and t r a n s p o r t e d t h r o u g h P r o f i l e s D and E i s d e p o s i t e d on t h e f o r e s h o r e a t Sand P o i n t , r e s u l t i n g i n s i g n i f i c a n t a c c r e t i o n a t t h i s l o c a t i o n . P r o f i l e B was g e n e r a l l y s u b j e c t e d t o a u n i f o r m l i t t o -r a l c u r r e n t d i r e c t i o n , bu t t h e s m a l l i n c i d e n t a n g l e o f waves r e s u l t e d i n o n l y m i n o r q u a n t i t i e s o f s and b e i n g t r a n s p o r t e d t h r o u g h t h e p r o f i l e . P r o f i l e s C and F were c h a r a c t e r i z e d by n e g l i g i b l e s a n d d r i f t , t h i s b e i n g l a r g e l y due t o t h e v e r y s m a l l wave i n -c i d e n t a n g l e s u s e d i n t h e c a l c u l a t i o n s . In t h e f i e l d , l i t t o r a l c u r r e n t s were o b s e r v e d t o be f a i r l y s t r o n g a t t i m e s , bu t a t b o t h l o c a t i o n s , t h e d i r e c t i o n s were h i g h l y v a r i a b l e . Sand t r a n s p o r t e d o n e way d u r i n g f l o o d t i d e was o f t e n b r o u g h t b a c k a g a i n d u r i n g ebb t i d e . T h e r e was t h u s an e x c e s s o f m a t e r i a l a t t h e s e l o c a t i o n s d u r i n g summer, a f a c t s u p p o r t e d by t h e i r c o n t i -n u a l a c c r e t i o n and l a c k o f p r o f i l e s e n s i t i v i t y t o t i d a l r ange 137. ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) . A p e r s i s t e n t r i p - c u r r e n t e x i s t e d b e t w e e n P r o f i l e s A and B, due p r o b a b l y t o o p p o s e d l i t t o r a l and l o n g s h o r e c u r r e n t d i r e c t i o n s i n t h i s a r e a ( s e e c h a p t e r on PLANIMETRIC S H A P E ) , and s i m i l a r l y b e t w e e n P r o f i l e s F and G ( f r o m o b s e r v a t i o n ) . Be tween P r o f i l e s B and D, and E and F , n a r r o w r i p - c u r r e n t c h a n n e l s f r e q u e n t l y c u t a c r o s s b e a c h r i d g e s where t h e y e x i s t e d , and were o b s e r v e d t o m i g r a t e up and down t h e l e n g t h o f t h e b e a c h . T h e s e r i p - c u r r e n t s d e v e l o p e d where two o p p o s i n g l i t t o r a l c u r -r e n t s c o n v e r g e d , and a s l i g h t c h a n g e i n t h e a n g l e o f a p p r o a c h o f d e e p - w a t e r waves was p r o b a b l y s u f f i c i e n t t o a l t e r t h e l i t -t o r a l c u r r e n t d i r e c t i o n s and i n t e n s i t i e s i n t h e s e a r e a s c o n -s i d e r a b l y . 138. I X , S A N D MOVEMENT 3A S E D ON T K A C E K DISPERSION A. I N T K O D U C T I Q N T h i s i n v e s t i g a t i o n was c o n d u c t e d t o e x a m i n e t h e manner o f s e d i m e n t movement a c r o s s t h e f o r e s h o r e . T h r e e e n -v i r o n m e n t s were s e l e c t e d f o r t h i s p u r p o s e , e a c h one h a v i n g d i s t i n c t f o r e s h o r e c h a r a c t e r i s t i c s - P r o f i l e s B, C and D ( s e e c h a p t e r on TRANSVEhSE P R O F I L E S ) . The d u r a t i o n o f e a c h e x p e r i -ment was o n e t i d a l c y c l e , and t h e r e f o r e , t h e d i r e c t i o n and i n -t e n s i t y o f i n d i c a t e d l i t t o r a l d r i f t f o r t h e t h r e e a r e a s a r e no t t y p i c a l o f t h e summer r e g i m e ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS), A s p a c e i n t e g r a t e d t e c h n i q u e was e m p l o y e d ( W r i g h t , 1962; Y a s s o , 1962) u s i n g s and t r a c e r s a t P r o f i l e s B and C, and sand as w e l l as g r a v e l t r a c e r s a t P r o f i l e D. Sand t r a c e r d i s -p e r s i o n s were a n a l y s e d w i t h t h e a i d o f t r e n d s u r f a c e a n a l y s i s ( B o o n , 1 9 6 8 ) , and g r a v e l t r a c e r s by d e t e r m i n i n g t h e i r mean v e c t o r d i s p l a c e m e n t s . P e b b l e o r i e n t a t i o n m e a s u r e m e n t s were a l s o made a t P r o f i l e D, t o s u p p l e m e n t t h e g r a v e l t r a c e r i n f o r m a t i o n . In c o n j u c t i o n w i t h t h e s e e x p e r i m e n t s , t h e p r o f i l e s t h e m s e l v e s were m e a s u r e d a t h a l f - h o u r i n t e r v a l s , t o d e t e r m i n e t h e d e p t h o f f o r e s h o r e d i s t u r b a n c e d u r i n g t h e t i d a l c y c l e ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) . B. TECHNIQUES I. TKACER PREPARATION At e a c h o f t h e t h r e e a r e a s s t u d i e d , s and t o be u s e d 139. as t r a c e r m a t e r i a l was d e r i v e d from two l o c a t i o n s , one above and the o the r below the l i n e o f emergence o f the water t a b l e ( F i gu re s 33, 35 and 37) . At low t i d e on the day p receed ing each exper iment , the sand was c o l l e c t e d us ing a c y l i n d r i c a l t i n measuring 0.35 f e e t in d iameter and depth. Th i s depth was found s u f f i c i e n t to i n su re c o n t i n u a l t r a c e r supply so long as e r o s i o n p r e v a i l e d at the source l o c a t i o n s du r ing the exper iments ( F i gu re 32) . A f l u o r e s c e n t p a i n t with brand name " K r y l o n " was used f o r marking the t r a c e r s . It c o n t a i n e d an a c r y l i c e s t e r r e s i n which rendered i t r e s i s t a n t to a b r a s i o n , and the c o l o u r s u sed , r e d , b l u e and g reen , were b r i l l i a n t in both d a y l i g h t and u 1 1 r a v i o l e t I i gh t . Sand marking was accompl i shed by sp ray ing the d e s i r e d p a i n t i n t o a p l a s t i c bag c o n t a i n i n g the dry sand. Through v i go rous shak ing , the sand e v e n t u a l l y became s a t u r a t e d with p a i n t . It was then spread t h i n l y over paper to d r y , , a n d a f t e r -wards passed through a 0.25 mm screen (except D red) to remove cIumps, Be fo re mark ing,approx imate 1y 50 gms o f sand was r e t a i n e d f o r s i z e a n a l y s i s , the r e s u l t s o f which are shown in Tab!e X I I : I ko. P r o f i Ie T r a c e r Mean (0) S t a n d a rd Devi a t i on (0) V e r b a l s o r t i n g s c a l e ( F r i e d m a n , 1962) B Red B i u e 2,63 2,64 0 ,28 0 , 3 0 V e r y we 1 1 s o r t e d V e r y we 11 so r t e d C R e d / B I u e G r e e n 2„G7 2,65 0 , 2 9 0 , 3 0 V e r y wei 1 s o r t e d V e r y we 11 s o r t e d D Red G r e e n 0 ,78 2. 22 1,47 0 .79 P o o r l y s o r t e d M o d e r a t e l y w e l l s o r t e d T a b l e XI I „ T e x t u r a l P a r a m e t e r s o f Sand T r a c e r s At low t i d e on t h e e x p e r i m e n t a l d a y s , t h e t r a c e r s were r e t u r n e d to t h e i r r e s p e c t i v e s o u r c e l o c a t i o n s . T h r e e g r a v e l s i z e s were h a n d - p i c k e d a l o n g t h e b e a c h f o r u s e as t r a c e r s a t P r o f i l e D. They were s p r a y p a i n t e d w i t h d i f f e r e n t c o l o u r s , and t h e n p l a c e d i n c i r c u l a r a r e a s on t h e f o r e s h o r e where t h e i r s i z e s m a t c h e d g r a v e l e x p o s e d a t t h e t i m e . B l u e p e b b l e s were p o s i t i o n e d on a n a r r o w s t r i p o f e q u i v a l e n t s i z e d m a t e r i a l , i n t h e m i d d l e o f a c o a r s e p e b b l e s e c t i o n ( s e e p a n e l a d j a c e n t t o p r o f i l e l i n e i n F i g u r e 3 7 ) . The p r o p e r t i e s and p e r c e n t a g e r e c o v e r y o f g r a v e l t r a c e r s a r e shown i n T a b l e X I I I . C o l o u r Mean G e n e r a 1 Number o f p a r t i c l e s % i n t e rmedi a t e a x i s ( i ) (mm) s h a p e Emp1aced R e c o v e r e d R e c o v e r y Whi t e 76 El 1 i p s o i da 1 16 4 25 Red 32 Di s c o i da 1 100 64 64 B Iue 16 1 r r e g u 1 a r 300 238 79 Tab Ie X I I I . P r o p e r t i e s and P e r c e n t a g e R e c o v e r y o f G r a v e l T r a c e r s , 141. 2. GRID DIMENSIONS AND SAMPLE RECOVERY R e c t a n g u l a r g r i d s were e m p l o y e d f o r r e c o v e r i n g s and t r a c e r s , t h e d i m e n s i o n s and l o c a t i o n s o f w h i c h were b a s e d on h o u r l y o b s e r v a t i o n s o f h y d r o d y n a m i c c o n d i t i o n s a t e a c h l o c a -t i o n . A t P r o f i l e D, h o w e v e r , g r i d l o c a t i o n s were d i c t a t e d by t h e t e x t u r e o f t h e f o r e s h o r e . To i n s u r e t o t a l t r a c e r r e c o v e r y , s a m p l i n g d e p t h was d e s i g n e d t o e x c e e d f o r e s h o r e e r o s i o n as i n -d i c a t e d by t h e h a l f - h o u r l y p r o f i l e m e a s u r e m e n t s . T h i s d e p t h was 0 . 4 f e e t , ^nd was a c c o m p l i s h e d u s i n g a p l a s t i c c o r i n g t u b e w i t h i n s i d e d i a m e t e r o f 0.I I f e e t . G r a v e l t r a c e r s were s i m p l y p o s i t i o n e d by t a p i n g t h e i r l o c a t i o n s f r o m two w i d e l y s p a c e d p r o f i l e r o d s . 3. ENVIRONMENTAL CONDITIONS Whereas t h e e x p e r i m e n t a t P r o f i Ie B was c o n d u c t e d on a f o r e s h o r e i n e q u i l i b r i u m w i t h t h e summer r e g i m e , a v i o -l e n t summer s t o r m a f f e c t e d t h e f o r e s h o r e p r i o r t o t h e e x p e r i -ments at P r o f i l e s C and D. P r o f i l e C was r e l a t i v e l y l i t t l e d i s t u r b e d , b u t P r o f i l e D was r e d u c e d to a c o n d i t i o n s i m i l a r t o t h a t i n l a t e S p r i n g ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) . H y d r o d y n a m i c and a t m o s p h e r i c c o n d i t i o n s t h a t p r e -v a i l e d on t h e e x p e r i m e n t a l day s a r e shown i n T a b l e X IV. 142. P r o f i Ie B r e a k e r Swash Wi nd H e i g h t ( f t ) P e r i o d ( s e e s ) Di r e c t i on P e r i o d ( s e e s ) B i - 2 10 Weak SE 13 L i g h t NW C i - 3 iO S t r o n g MW 1 1 L i g h t S D 2 - 5 9 S t r o n g SE/NW 10 None Tab Ie X I V c H y d r o d y n a m i c P a r a m e t e r s and A t m o s p h e r i c C o n d i t i o n s on E x p e r i m e n t a l Days. 4. SURVEY AND PHOTOGRAPHS As soon as t h e t r a c e r s were e m p l a c e d , e a c h a r e a was p l a n e - t a b l e d on a s c a l e o f I i n c h = 200 f e e t ( F i g u r e s 3 3 , 35 and 3 7 ) . P h o t o g r a p h s o f t h e a r e a s were t a k e n a t i t - h o u r i n t e r -v a l s t o p o r t r a y t h e h y d r o d y n a m i c c o n d i t i o n s w i t h t i d e l e v e l ( P l a t e s 12a, b , c; 13a,b, c; 14a, b, c ) . The t i m e s a t w h i c h t h e y were t a k e n , and p e r t i n e n t t i d a l i n f o r m a t i o n a r e g i v e n i n T a b l e XV. P r o f i Ie Day T i d a l H i g h Ti de P h o t o g r a p h t i m e ( h r s ) Range ( f t ) T i me ( h r s ) He i q h t \ f t j a b c B Aug.9 6.9 1430 10.9 1500 1630 1800 C Aug.23 5.7 1340 10.0 1430 1600 1730 D Aug.25 7.8 1440 10.8 1500 1630 1800 T a b l e XV. T i d a l I n f o r m a t i o n and P h o t o g r a p h T i m e s on E x p e r i m e n t a l D a y s , 5. COUNTING PROCEDURES Each s a m p l e was s p l i t f o u r t i m e s w i t h a m i c r o s p I i t t e r , 143. and t h e b a l a n c e s p r e a d t h i n l y o v e r w h i t e p a p e r f o r e x a m i n a t i o n u n d e r u l t r a v i o l e t l i g h t . The lamp u s e d was a M i n e r a l i g h t M-15, w h i c h c o m b i n e d b o t h l ong and s h o r t w a v e r a d i a t i o n . When doub t e x i s t e d as t o t h e i d e n t i t y o f a p a r t i c l e , i n s p e c t i o n u n d e r w h i t e l i g h t was u s u a l l y s u f f i c i e n t t o d e c i d e . C . TREND SURFACE ANALYSIS AND COMPUTER PKOGKAHMING S p a c e i n t e g r a t e d s t u d i e s were u n t i l r e c e n t l y o f l i t t l e v a l u e i n e x p l a i n i n g f o r e s h o r e s e d i m e n t movement , s i n c e l o c a l v a r i a b i l i t y o f t h e raw d a t a c o u l d n o t be a c c o u n t e d f o r ( W r i g h t , 1962; Y a s s o , 1962). By t h e a p p l i c a t i o n o f t r e n d s u r -f a c e a n a l y s i s t o t h e p r o b l e m , Boon (1968) was t h e f i r s t i n v e s -t i g a t o r t o make o b j e c t i v e a s s e s s m e n t s on r e a l t r e n d s . T r e n d s u r f a c e a n a l y s i s i s a p r o c e d u r e w h i c h d i s s e c t s t h e raw d a t a i n t o two c o m p o n e n t s : X = x + e ( I ) n n n where X p = raw d a t a x n = t r e n d component e p = r e s i d u a l component The t r e n d component c a n be d e f i n e d by a g e n e r a l p o l y n o m i a l : x = a + a.U + a 0 V + a 3 U 2 + a,UV + a c V 2 + (2) n o I l j> H b t- h where x n = i s t h e t r e n d component o f t h e n o b s e r v a t i o n p o i n t ( U , V ) = g e o g r a p h i c c o o r d i n a t e s o f t h e n o b s e r v a t i o n on a g r i d aQ,aj,a2i..= c o e f f i c i e n t s . B o t h X and x may be c o n s i d e r e d t o be v a l u e s a l o n g a n n \kk. p e r p e n d i c u l a r l i n e w i t h c o o r d i n a t e s (U ,V ) on t h e 2 - d i m e n s i o n a I g r i d . P o l y n o m i a l s o f any o r d e r may be f i t t e d t o t h e raw d a t a 0 F o r e a c h o f t h e s e t r e n d s u r f a c e s ( i i n e a r , q u a d r a t i c , e t c . ) , t h e c o e f f i c i e n t s a Q , a | , a a r e d e t e r m i n e d by l e a s t s q u a r e s p r o c e d u r e s such t h a t 2 £ ( X „ - x ) = minimum ..,.(3) n n The c o e f f i c i e n t s a r e t h e n s u b s t i t u t e d i n t o t h e p o l y n o m i a l e q u a t i o n , and t r e n d c o m p o n e n t s a r e f o u n d f o r e a c h s a m p l e on t h e g r i d . As t h e p o l y n o m i a l o r d e r i s i n c r e a s e d , t h e s m a l l e r t h e d e v i a t i o n b e c o m e s , and t h e c l o s e r t h e t r e n d s u r f a c e a p -p r o a c h e s h a n d - c o n t o u r e d raw d a t a . In most g e o l o g i c a l a p p l i c a t i o n s o f t r e n d s u r f a c e a n a l y s i s e . g . r e g i o n a l g e o c h e m i c a l a s s a y s , t h e p u r p o s e i s t o e l i m i n a t e r e g i o n a l t r e n d s o f s y s t e m a t i c v a r i a t i o n i n o r d e r t o a l l o w c o n c e n t r a t i o n on t h e a n o m a l o u s d e v i a t i o n s . In t h i s t y p e o f s t u d y t h e i n t e n t i o n i s j u s t t h e r e v e r s e , t h a t i s , r e a l t r e n d s i n p a r t i c l e d i s p e r s i o n a~e s o u g h t by e l i m i n a t i n g t h e l o c a l v a r i a b i l i t y o f e a c h s a m p l e . A p r o g r a m w r i t t e n by A . J , S i n c l a i r f o r u s e on an IBM 70k0/kk c o m p u t e r was u s e d t o c a l c u l a t e t h e c o e f f i c i e n t s f o r l i n e a r t o s i x t h o r d e r p o l y n o m i a l s . T w e l v e p l o t s were t h u s o b t a i n e d f o r e a c h t r a c e r c o l o u r - s i x t r e n d s u r f a c e maps , and t h e c o r r e s p o n d i n g s i x r e s i d u a l p o i n t p l o t s . C o m p u t e r o u t p u t a l s o i n c l u d e d t h e s t a n d a r d d e v i a t i o n , t o t a l v a r i a t i o n , v a r i a -\ks. t i o n e x p l a i n e d , and c o e f f i c i e n t o f d e t e r m i n a t i o n f o r e a c h s u r -f a c e . T r e n d s u r f a c e d i a g r a m s shown i n F i g u r e s 34, 36 and 38 were s e l e c t e d f o r i n t e r p r e t a t i o n f r om 84 c o m p u t e r p l o t s f o r t h e f o l l o w i n g r e a s o n s : E x p e r i m e n t s a t P r o f i l e s B and C show r e m a r k a b l y s i m i l a r t r e n d p a t t e r n s , a p p a r e n t l y r e l a t e d t o b e a c h c u s p f o r m a t i o n . The t r e n d p a t t e r n s shown f o r P r o f i l e D, t o g e t h e r w i t h g r a v e l d i s p e r s i o n p a t t e r n s , and p e t r o f a b r i c a n a l y s i s o f p e b b l e o r i e n t a t i o n s , s u c c e s s f u l l y e x p l a i n t h e c o m p l e x h y d r o -d y n a m i c e n v i r o n m e n t p r e s e n t t h e r e . A l l t h e t r e n d s u r f a c e s p r e s e n t e d , f o r P r o f i l e s B, C and D, show good d e f i n i t i o n and h i g h r e s o l u t i o n . C o e f f i c i e n t s o f d e t e r m i n a t i o n f o r l i n e a r , q u a d r a t i c and c u b i c s u r f a c e s shown f o r P r o f i l e D a r e a l l s i g n i f i c a n t l y n o n - r a n d o m a t t h e 5% l e v e l o f s i g n i f i c a n c e ( H o w a r t h , 1967). The c o e f f i c i e n t s o f d e t e r m i n a t i o n o f q u a r t i c s u r f a c e s shown f o r P r o f i l e s B and C a r e a l l s u f f i c i e n t l y h i g h t o be c o n -s i d e r e d as n o n - r a n d o m . S t a t i s t i c a l d a t a and o t h e r i n f o r m a t i o n p e r t a i n i n g t o t h e s e s u r f a c e s , a r e shown i n T a b l e X V I „ 146. P ro - Fi gure T r a c e r G r i d Number Trend C o e f f . o f Standard f i le Number co iou r s i ze o f su r f a c e d e t e r m i - devi at ion ( f e e t ) samp 1es deg ree na t i on B 34 - 2a Red 40 x 90 50 4 0.647 1.43 34 - l a B Iue 40 x 90 50 4 0.492 2.83 C 36 - 3a B iue 80 x 90 50 4 0.373 1.85 36 - 2a Red P0 x 90 50 4 0.830 2.92 36 - l a G reen 80 x 90 50 4 0.522 2.49 D 38 - 3a Red 60 x 30 28 3 0.308 4.55 38 - 2a Red 25 x 10 15 3 0.650 15.47 38 - l a Green 60 x 30 28 3 0.755 2.27 38 - 3c Red 60 x 30 28 1 0. 195 4.91 38 - 2c Red 25 x 10 15 2 0.605 16.45 38 - Ic Green 60 x 30 28 1 p.514 i 3. 19 Tab Ie X V I . T r e n d S u r f a c e S t a t i s t i c a l D a t a , and S a m p l i n g I n f o r m a t i o n a t P r o f i l e s B,C, and D. D. RESULTS I . PROF ILE B ENVIRONMENT The d i s p e r s a l p a t t e r n s o f b l u e and r e d t r a c e r a r e v e r y s i m i l a r , as i n d i c a t e d i n t h e t r e n d s u r f a c e d i a g r a m s ( F i g u r e s 34 - l a , 2a ) . T h i s f a c t w o u l d h a v e b e e n m i s s e d had t h e h a n d -c o n t o u r e d raw d a t a d i a g r a m s b e e n c o n s i d e r e d ( F i g u r e s 34 - l b , 2b) . N o t e t h a t t h e two t r a c e r s o u r c e s were l o c a t e d 75 f e e t a p a r t , and t h e edge o f t h e s a m p l e g r i d c o i n c i d e d w i t h t h e p r o f i l e l i n e ( F i g u r e 33). From h a l f - h o u r l y p r o f i l e m e a s u r e m e n t s ( F i g u r e 29 ) , i t a p p e a r s t h a t t h e b l u e t r a c e r s o u r c e was p r o b a b l y a f f e c t e d t w i c e by t h e backwash i . e . d u r i n g f l o o d t i d e as w e l l as ebb t i d e . The r e d t r a c e r h o w e v e r , was e r o d e d o n l y o n c e v i z , a t h i g h t i d e . F o r t h i s r e a s o n , b l u e t r a c e r i s o p l e t h v a l u e s a r e h i g h e r t h a n t h e r e d o n e s i n t h e t r e n d s u r f a c e d i a g r a m s ( F i g u r e s 147. 34 - l a , 2 a ) . The main f e a t u r e s o f these diagrams a r e : D i s p e r s a l p a t t e r n s a r e s i m i l a r r e g a r d l e s s o f t r a c e r s o u r c e l o c a t i o n . Two e l o n g a t e h i g h - c o n c e n t r a t i o n zones, w i t h long axes o r i e n t e d normal to the c o a s t l i n e , o c c u r a p p r o x i m a t e l y 30 f e e t a p a r t i n both diagrams. The l o c i o f maximum t r a c e r c o n c e n t r a t i o n a r e l o c a t e d at a p p r o x i m a t e l y c o i n c i d e n t p o i n t s w i t h i n the h i g h zone a d j a -cent t o the p r o f i l e l i n e , and c l o s e to the water t a b l e l i n e o f emergence ( F i g u r e s 33 and 3 4 ) . R e s i d u a l diagrams ( F i g u r e s 34 - I c , 2c) have been i n c l u d e d s i m p l y t o i l l u s t r a t e the e x t e n t o f d e v i a t i o n o f the q u a r t i c t r e n d s u r f a c e s from the hand-contoured raw d a t a . FIGURE 34 P R O F I L E © P l a t e 12a, P r o f i l e B s h o r t l y a f t e r p e a k h i g h t i d e . P h o t o g r a p h t i m e - 1500 h o u r s . P l a t e 12b, P r o f i l e B, P h o t o g r a p h t i m e 1630 h o u r s . P l a t e 12c. P r o f i Ie B, P h o t o g r a p h t i m e 1800 h o u r s . 150 151. 2. PROF ILE C ENVIRONMENT The t h r e e t r e n d s u r f a c e s ( F i g u r e s 36 - l a , 2 a , 3a) show t h a t a s i m i l a r d i s p e r s a l p a t t e r n has a g a i n e m e r g e d , and f u r t h e r m o r e , t h a t t h e y b e a r a r e m a r k a b l e r e s e m b l a n c e t o t h e d i s -p e r s a l p a t t e r n s f o u n d at P r o f i l e B, a l t h o u g h on a l a r g e r s c a l e . H e r e t o o , a b a s i c t r e n d w o u l d have b e e n o b s c u r e d by l o c a l v a r i -a b i l i t y i n t h e h a n d - c o u n t o u r e d raw d a t a ( F i g u r e s 36 - l b , 2 b , 3 b ) . N o t e t h a t t h e t r a c e r s o u r c e s were l o c a t e d 50 f e e t a p a r t , and t h e edge o f t h e s amp le g r i d was l o c a t e d 20 f e e t d o w n d r i f t f r o m t h e p r o f i l e l i n e ( F i g u r e 3 5 ) . From h a l f - h o u r l y p r o f i l e m e a s u r e m e n t s ( F i g u r e 3 0 ) , i t a p p e a r s t h a t t h e g r e e n t r a c e r s o u r c e was e r o d e d c o n t i n u o u s l y d u r i n g f l o o d t i d e . The r e d / b l u e t r a c e r s o u r c e h o w e v e r , was e r o d e d t w i c e , t h e r e d ( t o p ) a l m o s t t o t a l l y by f l o o d t i d e b a c k -w a s h , and t h e b l u e ( b o t t o m ) o n l y s l i g h t l y by ebb t i d e b a c k -wash . F o r t h e s e r e a s o n s , g r e e n i s o p l e t h v a l u e s a r e i n t e r m e d i a t e b e t w e e n h i g h r e d v a l u e s and low b l u e v a l u e s i n t h e t r e n d s u r -f a c e d i a g r a m s ( F i g u r e s 36 - l a , 2 a , 3 a ) . The ma in f e a t u r e s o f t h e s e d i a g r a m s a r e : D i s p e r s a l p a t t e r n s a r e s i m i l a r r e g a r d l e s s o f t r a c e r s o u r c e l o c a t i o n Two e l o n g a t e h i g h c o n c e n t r a t i o n z o n e s , w i t h l ong a x e s o r i e n t e d norma l t o t h e c o a s t l i n e , o c c u r a p p r o x i m a t e l y 60 f e e t a p a r t f o r t h e g r e e n t r a c e r . F o r r e d and b l u e t r a c e r s , t h e s e same z o n e s a r e o c c u p i e d by low c o n c e n t r a t i o n s . 152. The locus o f maximum green t r a c e r c o n c e n t r a t i o n l i e s w i t h i n the h i g h zone n e a r e s t t o the p r o f i l e l i n e . Maximum red and b l u e t r a c e r l o c i o c c u r w i t h i n a h i g h - c o n c e n t r a t i o n tongue i n t h e m i d d l e o f the g r i d . The red t r a c e r stems from a h i g h c o n c e n t r a t i o n area i n the upper l e f t - h a n d c o r n e r o f the g r i d , and was t r a n s p o r t e d i n a d i r e c t i o n opposed to the d r i f t d i r e c t i o n . B l u e t r a c e r was s i m p l y t r a n s p o r t e d d i r e c t l y from the sour c e i n the same d i r e c t i o n as the d r i f t d i r e c t i o n . Both red and b l u e tracer maxima l i e c l o s e to the water t a b l e l i n e o f emergence ( F i g u r e s 35 and 3 6 ) . PROFILE © Primary rods O Secondary rods # Tracer source 0 Grid samples F I G U R E 35 1C 5 o o o -120-o _o_ -115-MHT . P.. -o— RED/ BLUE -11 0-• a a a a a Q~ W j ( « r " t a ? c O O • D O High tide o o o o • GREEN o o o o -10-5--10 o-o o o o o o o 9-5 P R O F I L E © quartic trend surface hand-contoured raw data Feet O 10 ' 20 P l a t e 13a. P r o f i l e C s h o r t l y a f t e r peak h i g h t i d e . P h o t o g r a p h t i m e 1430 h o u r s . P l a t e 13b. P r o f i l e C. P h o t o g r a p h t i m e 1600 h o u r s . P l a t e 13c. P r o f i l e C. P h o t o g r a p h t i m e 1730 h o u r s . 156. 3. PROFILE D ENVIKONMENT (a) Sand T r a c e r s These t rend s u r f a c e diagrams (F i gu re s 38 - l a , 2a, 3a and Ic, 2c , 3c) are comp le te l y d i f f e r e n t from those o f P r o f i l e s B and C, a l though a d i s t i n c t d i s p e r s a l p a t t e r n does e x i s t between them. T h i s p a t t e r n i s aga in obscured by l oca l v a r i a b i l i t y in the hand-countoured raw data diagrams (F i gu re s 38 - l b , 2b, 3b) . Due to the p r e v a l e n c e o f g rave l in the mid -f o r e s h o r e r e g i o n , the two t r a c e r sources were spaced w ide ly apart v i z . 150 f e e t ( F i gu re 37) . A l s o , two sampling g r i d s were n e c c e s s a r y , both be ing p o s i t i o n e d over the p r o f i l e l i n e due to u n c e r t a i n t y about the observed d r i f t d i r e c t i o n (Tab le X IV). From h a l f - h o u r l y p r o f i l e measurements ( F i gu re 31 ) , i t i s impos s i b l e to assess the f requency and i n t e n s i t y o f e r o s i o n o f the green t r a c e r sou rce , but i t i s c l e a r that some d i d occur dur ing f l o o d t i d e . The red t r a c e r source was eroded on l y once v i z . at h igh t i d e . An i n s i g n i f i c a n t amount o f green t r a c e r was t r a n s p o r t e d up the f o re sho re acros s the g rave l dur ing f l o o d t i d e , a t o t a l o f ten p a r t i c l e s be ing noted from a l l o f the small g r i d samples, C o n v e r s e l y , a c o n s i d e r a b l e amount o f red t r a c e r was c a r r i e d down the f o re sho re with ebb t i d e . It was d i s p e r s e d over the large g r i d in q u a n t i t i e s s i m i -l a r to the green t r a c e r , as shown by roughly e q u i v a l e n t i s o -p l e t h v a l u e s on the t rend s u r f a c e diagrams ( F i gu re s 38 - l a , 2a , 3a and Ic, 2c, 3 c ) . The small g r i d , due to c l o s e p r o x i m i t y 157.-o f t h e r e d t r a c e r s o u r c e , and a l s o b e c a u s e o f i t s s m a l l a r e a ; has v e r y h i g h r e d t r a c e r i s o p l e t h v a l u e s ( F i g u r e s 38 - 2 a , 2 c ) . The ma in f e a t u r e s o f t h e s e t r e n d s u r f a c e d i a g r a m s a r e : S i m i l a r i t y o f g r e e n and r e d d i s p e r s a l p a t t e r n s on t h e l a r g e g r i d , r e g a r d l e s s o f t r a c e r s o u r c e l o c a t i o n . A h i g h c o n c e n t r a t i o n z o n e , o r i e n t e d s u b - p a r a l l e l t o t h e c o a s t l i n e , o c c u r s on b o t h l a r g e and s m a l l g r i d s ( c / f P r o f i l e s 8 and C ) . The l o c i o f maximum g r e e n and r e d t r a c e r c o n c e n t r a t i o n s l i e b e l o w t h e b o t t o m r i g h t - h a n d c o r n e r o f t h e l a r g e g r i d ( F i g u r e 3 7 ) , r e s u l t i n g i n s l i g h t skewnes s o f t h e i s o p l e t h l i n e s f r o m t r u e c o a s t l i n e p a r a l l e l i s m ( F i g u r e 38 - l a , 3a and I c , 3 c ) . The l o c u s o f maximum r e d t r a c e r c o n c e n t r a t i o n on t h e s m a l l g r i d l i e s a b o v e t h e t o p r i g h t - h a n d c o r n e r o f t h e d i a g r a m s , r e s u l t i n g i n s l i g h t s kewnes s o f t h e s e i s o -p l e t h l i n e s as w e l l ( F i g u r e s 38 - 2a and 2 c ) . No te t h a t s kewnes s d i r e c t i o n s o f t h e l a r g e and s m a l l g r i d s a r e o p p o s i t e t o e a c h o t h e r , i n d i c a t i n g t h a t t r a c e r m a t e r i a I was c a r r i e d s o u t h e a s t w a r d s ( r i g h t - h a n d s i d e o f t h e p r o -f i l e l i n e - F i g u r e 37) a b o v e and b e l o w t h e g r a v e l z o n e . The w a t e r t a b l e l i n e o f e m e r g e n c e on t h e l a r g e g r i d , marks z o n e s o f mTnltnum g r e e n and r e d t r a c e r c o n c e n t r a t i o n s , (b) G r a v e l T r a c e r s P a r t i c l e d i s p e r s i o n o f t h e t h r e e g r a v e l f r a c -t i o n s i s shown In F i g u r e 37. The s t a t i s t i c a l l y h i g h p e r c e n t a g e o f r e c o v e r y and d i s t i n c t i v e s p r e a d o f t h e two p e b b l e c l a s s e s , 158. s u g g e s t s t h a t t h e i r d i s p e r s i o n p a t t e r n s a r e m e a n i n g f u l . C o b b l e r e c o v e r y , c o n t r a r y t o e x p e c t a t i o n , was p o o r ( T a b l e X I I I ) , and i t s d i s p e r s i o n p a t t e r n s h o u l d be c o n s i d e r e d w i t h r e s e r v a t i o n . T r e n d s u r f a c e a n a l y s i s c o u l d h a v e b e e n a p p l i e d t o t h i s d a t a , b u t due t o t h e r e l a t i v e l y low c o n c e n t r a t i o n c'f t r a -c e r p a r t i c l e s o v e r a f a i r l y l a r g e a r e a , i t was c o n s i d e r e d im -p r a c t i c a l . I n s t e a d , a p o i n t - c o u n t e r was e m p l o y e d t o a s s i g n t r a c e r p a r t i c l e c o n c e n t r a t i o n s on a r e c t a n g u l a r g r i d . T h e s e v a l u e s were t h e n h a n d - c o n t o u r e d , and a r e shown as i n s e t s i n F i g u r e 37. Mean v e c t o r d i s p l a c e m e n t f o r e a c h g r a v e l s i z e was c a l c u l a t e d w i t h t r a c e r s o u r c e as o r i g i n i . e . (^-—- ^-LQ) 3 n n where x and y a r e t h e c o o r d i n a t e s , c i s t h e c o l o u r , a n d n i s t h e number o f p a r t i c l e s r e c o v e r e d . The mean v e c t o r s were t h e n t r a n s p o s e d b a c k t o t h e b e a c h p l a n o f F i g u r e 37* The ma in f e a t u r e s o f g r a v e l d i s p e r s i o n a r e as f o l l o w s : A l l b u t one o f t h e p a r t i c l e s moved n o r t h w e s t f r o m t h e p r o -f i l e l i n e (a c o a r s e r e d p e b b l e moved t o t h e r i g h t - h a n d s i d e o f t h e s m a l l g r i d ) . B a s e d on mean v e c t o r d i r e c t i o n s , t h e b l u e p e b b l e s m i g r a t e d up t h e f o r e s h o r e , c o a r s e r e d p e b b l e s r e m a i n e d on c o n t o u r , and w h i t e c o b b l e s m i g r a t e d down t h e f o r e s h o r e . T h i s t r e n d i n d i c a t e s a c o a r s e n i n g t e x t u r e t o w a r d s t h e l ower f o r e s h o r e . B a s e d on mean v e c t o r l e n g t h s , i t i s e v i d e n t t h a t t h e r a t e o f p a r t i c l e movement ?s i n v e r s e l y p r o p o r t i o n a l t o t h e p a r t i c l e s i z e i . e . b l u e p e b b l e s moved ?4,5 f e e t , c o a r s e r e d p e b b l e s moved 23.5 f e e t , a n d w h i t e c o b b l e s moved !2,0 f e e t . P R O F I L E © RED c u b i c t r e n d s u r f a c e , RED IT 1216% 12 8 8 8 > 4 ^ ////// t /—N \ h a n d - c o n t o u r e d r a w d a t a c u b i c t r e n d s u r f a c e RED ^ 8 g V ^ 6 0 , 8 0 _£2_ 2b h a n d - c o n t o u r e d r a w d a t a c u b i c t r e n d s u r f a c e h a n d - c o n t o u r e d r a w d a t a Feet 0 10 20 l i n e a r t r e n d s u r f a c e h a n d - c o n t o u r e d l i n e a r r e s i d u a l i n u n i t s o f s t a n d a r d d e v i a t i o n 2c q u a d r a t i c t r e n d s u r f a c e GREEN GREEN l i n e a r t r e n d s u r f a c e h a n d - c o n t o u r e d l i n e a r r e s i d u a l i n u n i t s o f s t a n d a r d d e v i a t i o n P l a t e 14a. P r o f i l e D s h o r t l y a f t e r peak h i g h t i d e . P h o t o g r a p h t i m e 1500 h o u r s . P l a t e 14b. P r o f i l e D. P h o t o g r a p h t i m e 1630 h o u r s . P l a t e 14c. P r o f i l e D, P h o t o g r a p h t i m e 1800 h o u r s . 162. ( c ) P e b b l e O r i e n t a t i o n and Movement A t o t a l o f 68 p e b b l e o r i e n t a t i o n m e a s u r e m e n t s were made a l o n g a o n e f o o t w i d e s t r i p a d j a c e n t t o t h e p r o f i l e l i n e when t h e t i d e had r e c e e d e d „ T h i s was a c c o m p l i s h e d u s i n g a 3 f o o t l ong s t e e l r o d , w h i c h was o r i e n t e d v i s u a l l y t o a l i g n w i t h t h e p e b b l e s h o r t a x e s . The b e a r i n g and p l u n g e o f t h e r o d a t e a c h p e b b l e l o c a t i o n was t h e n m e a s u r e d and r e c o r d e d . A l ower h e m i s p h e r e , e q u a l a r e a S c h m i d t p r o j e c t i o n o f t h e r e s u l t s i s shown i n F i g u r e 39, t h e ma in f e a t u r e o f w h i c h a r e : The m a j o r i t y o f p e b b l e s l i e f l a t on t h e b e a c h f a c e i . e . s h o r t axe s a r e v e r t i c a l . Some p e b b l e s a r e t i l t e d so t h a t t h e i r s h o r t a x e s p l u n g e d i r e c t l y l a n d w a r d - p r i m a r y t r e n d . Some p e b b l e s a r e t i l t e d so t h a t t h e i r s h o r t a x e s p l u n g e l a n d w a r d a t an a n g l e t o t h e p r o f i l e l i n e - s e c o n d a r y t r e n d . From o b s e r v a t i o n , p e b b l e t i l t i n g o n l y o c c u r r e d i n t h e u p p e r p o r t i o n o f t h e s w a s h - b a c k w a s h z o n e . At t h e e x t r e m e t o p o f t h i s z o n e c l o s e t o t h e swash l i m i t , p e b b l e s r e m a i n e d s t a t i o n a r y , and were u s u a l l y c o v e r e d by a t h i n v e n e e r o f l i g h t - c o l o u r e d s and by t h e swash . A t t h e b o t t o m p a r t o f t h e s w a s h - b a c k w a s h z o n e , p e b b l e s were r o l l e d down t h e f c r c s h o r e by t h e t u r b u l e n t b a c k w a s h . To c h e c k t h e manner i n w h i c h d i s c o i d a l p e b b l e s were r o l l e d a p p r o x i m a t e l y 50 o f them were p a i n t e d b l u e , and p l a c e d 163. on the beach face near the midd le o f the swash-backwash zone. It was apparent tha t by f a r the m a j o r i t y o f them r o l l e d edge-ways l i k e a wheel - an o b s e r v a t i o n supported by d i f f e r e n t i a l a b r a s i o n o f pa in t from the pebb le s . The edges were scoured c l e a n , whereas the f l a t s i de s showed on l y a few c h i p s in the pai n t . T i l t i n g o f pebb les in the upper p o r t i o n o f the swash-backwash zone was not due to wave impact, as has been p o s t u l a t e d by Emery ( I960). Rather , i t was due to the f o r c e o f backwash, which s imply l i f t e d the landward edges o f the d i s c s as i t became d e f l e c t e d around the pebb le s . These t h r e e areas o f pebb le behav iour in the swash-backwash zone are i l l u s t r a t e d in P l a t e 15. The secondary t r e n d e x h i b i t e d by the p e t r o f a b r i c diagram (F i gu re 39) i n d i c a t e s tha t backwash moved in a n o r t h -w e s t e r l y d i r e c t i o n , and by a s s o c i a t i o n , so d i d the swash. 164 PETROFABRIC DIAGRAM O F P E B B L E SHORT AXES (s), AT PROEILE © 165. f o r e s h o r e r e g i o n a t P r o f i Ie D. 166. E. DISCUSSION I. BEACH CUSP FORMAT I ON Gravel beaches are commonly marked by the presence o f runnels where l i t t o r a l c u r r e n t s are weak (Otvos, 1964) t It i s b e l i e v e d that these f ea tu re s are the p r e c u r s o r s to beach cusps , and form in response to d i f f e r e n t i a l f o r e s h o r e e r o s i o n by the backwash. The swash i s thought to be the agent r e s p o n s i b l e f o r t r an s fo rm ing these runnel forms i n t o cusp forms, by reduc ing the runnel lengths through wave impact. Due to the u n i f o r m i t y o f t e x t u r e o f sandy beaches, runnel format ion i s less e v i d e n t . However, P r o f i l e s B and C both e x h i b i t e l onga te zones o f t r a c e r c o n c e n t r a t i o n i n d i c a -t i v e o f t h e i r f o rma t i on . At P r o f i l e D, the on l y i n d i c a t i o n o f p o s s i b l e runnel development i s from the t h i r d o r d e r t rend su r -face o f red t racer 1 ( F i gu re 38 - 3a) . Here, a s h o r t , d i s t o r t e d tongue o f t r a c e r extends up the g r i d , suggest ing that a s t rong no r thwes te r l y moving longshore c u r r e n t i n h i b i t e d i t s proper development. At P r o f i l e C, a s e r i e s o f r e l i c t cobb le cusps e x i s t e d along the upper f o re sho re at the time o f the exper iment, wi th a wave length o f 90 fee t (F i gu re 35) . The e longa te zones o f t r a c e r c o n c e n t r a t i o n , however, were spaced 60 fee t a p a r t , thus negat ing any p o s s i b i l i t y o f a g e n e t i c r e l a t i o n s h i p . At P r o f i l e B, no r e l i c t cusps e x i s t e d ( F i gu re 33 ) , and the e l o n -gate t r a c e r c o n c e n t r a t i o n zones measured 30 fee t apa r t . The mechanism o f beach cusp ma in ta inance i s f a i r l y * See GLOSSARY 167. w e l l d o c u m e n t e d i n t h e l i t e r a t u r e , bu t t h e i r o r i g i n and r e g u l a r s p a c i n g r e m a i n e n i g m a t i c . Two r e c e n t t h e o r e t i c a l e x -p l a n a t i o n s o f t h i s p r o b l e m d e s e r v e c o n s i d e r a t i o n : C l o u d (1966) has a n a l o g i s e d a b r e a k i n g wave t o a l i q u i d c y l i n d e r , whose d i a m e t e r e q u a l s t h e wave h e i g h t . A p h y s i c a l r u l e e x i s t s w h i c h s t a t e s t h a t a l i q u i d c y l i n d e r becomes u n s t a b l e when i t s l e n g t h e x c e e d s 2 i l r , and i t t h e n s p l i t s i n t o s u b e q u a l d i v i s i o n s whose l e n g t h s a r e p r o p o r t i o n a l t o t h e c y l i n d e r ' s d i a m e t e r . C l o u d (1966) p o s t u l a t e d t h a t t h e moment a wave c o l l a p s e d , t h e segment s w o u l d s h o o t f o r w a r d as a r e g u l a r s p a c e d a r r a y o f j e t s , and t h a t i f c o n d i t i o n s were s u i t a b l e f o r r e g u l a r s e g m e n t a t i o n , b e a c h c u s p s w o u l d d e v e l o p . Bowen and Inman (1969) have s u g g e s t e d t h a t a f o r -m a t i v e r e l a t i o n s h i p e x i s t s b e t w e e n b e a c h c u s p s and r i p -c u r r e n t s , and t h a t b o t h a r e d e p e n d e n t on t h e wave h e i g h t . When t h e f o r e s h o r e d i p s g e n t l y s e a w a r d h o w e v e r , t h e y n o t e t h a t t h e wave l e n g t h o f c u s p s a r e g e n e r a l l y s m a l l c o m p a r e d t o t h e s p a c -i n g b e t w e e n r i p - c u r r e n t s . They s u g g e s t t h a t i n t h i s c a s e , c u s p s f o r m i n r e s p o n s e t o an i n t e r a c t i o n o f r e f o r m e d waves ( a s s o c i a -t e d w i t h t h e b o r e s o f b r e a k i n g w a v e s ) , and s m a l l edge waves t r a v e l l i n g i n t h e s u r f z o n e . The l e n g t h o f t h e edge waves w o u l d be d e t e r m i n e d by t h e d i s t a n c e be tween h e a d l a n d s e n c l o s i n g t h e b a y . P r a c t i c a l a p p l i c a b i l i t y o f e i t h e r o f t h e s e t h e o r i e s t o t n e f i e l d s i t u a t i o n i s d i f f i c u l t , s i n c e t h e wave c h a r a c t e r -* See GLOSSARY 168. I s t i e s w h i c h t h e y d e s c r i b e a r e not r e a d i l y a p p a r e n t . The b a c k -wash as t h e a g e n t r e s p o n s i b l e f o r c u s p g e n e s i s seems t o be a much more p r a c t i c a l answer t o t h e p r o b l e m . C o n s i d e r a t i o n o f a wedge o f w a t e r m o m e n t a r i l y p o s i -t i o n e d on a s l o p i n g f o r e s h o r e ( t h e i n s t a n t a swash r e a c h e s i t s u p p e r l i m i t ) , i t s w i t h d r a w l down t h e s l o p e ( t h e backwash ) w i l l n a t u r a l l y t a k e a d v a n t a g e o f any m i n o r t r a n s v e r s e d e p r e s s i o n s t h a t may e x i s t t h e r e . E r o s i o n i n t h e s e d e p r e s s i o n s w i l l be more i n t e n s e t h a n e l s e w h e r e , due t o t h e i n c r e a s e d v o l u m e o f w a t e r t h e r e ( G r a n t , 1948 ) . D e p e n d i n g on t h e t h i c k n e s s o f s u c c e e d i n g w a t e r w e d g e s , a m a l g a m a t i o n o f a number o f t h e s e t r a n s v e r s e d e p r e s s i o n s i n t o i n t e r - r u n n e l v a l l e y s , w i t h d i s t i n c t s p a c i n g s , w o u l d n a t u r a l l y f o l l o w . Runne l s h o r t e n i n g by wave i m p a c t , and v a l l e y t r a n s f o r m a t i o n i n t o r o u n d e d embayments by d i r e c t e d backwash e r o s i o n , w o u l d t h e n c r e a t e t h e p r o b l e m a t i c c u s p f o r m s . In c o n c l u s i o n t h e n , s e d i m e n t c o n c e n t r a t i o n on t h e f o r e s h o r e a p p e a r s t o be l a r g e l y c o n t r o l l e d by t h e c h a r a c t e r o f t h e b a c k w a s h . The swash s i m p l y c a r r i e s s e d i m e n t ( and t r a c e r m a t e r i a l ) up t h e b e a c h f a c e , and t h e r e t u r n i n g backwash d e t e r -m i n e s t h e l o c i , o f maximum t r a n s v e r s e e r o s i o n . The f a c t t h a t b e a c h c u s p s a p p a r e n t l y f o rm b e s t i n t h e r e g i o n o f t h e w a t e r t a b l e l i n e o f e m e r g e n c e , i s e x e m p l i f i e d a t P r o f i l e s B and C by maximum t r a c e r c o n c e n t r a t i o n s i n t h i s v i c i n i t y . P e r h a p s t h e d i f f e r e n t i a l s u s c e p t i b i l i t y t o e r o s i o n o f a d r y and wet 169. f o re sho re (Grant , 1948) accentua tes runnel development In t h i s a r e a . 2. LITTORAL DKIFT Space In teg ra ted t r a c e r s t u d i e s , by v i r t u e o f t h e i r d e s i g n , are not s u i t a b l e f o r de termin ing l i t t o r a l d r i f t v e l o -c i t i e s . Equa l l y good q u a l i t a t i v e i n f o r m a t i o n can be d e r i v e d s imply by o b s e r v i n g swash d i r e c t i o n s ac ros s the f o r e s h o r e (Tab le X IV) . From the p resent t r a c e r i n v e s t i g a t i o n s , a l l that can be s a i d i s that at P r o f i l e B, the l i t t o r a l d r i f t was weak, and in a s o u t h e a s t e r l y d i r e c t i o n ; at P r o f i l e C, i t was r e l a -t i v e l y s t r o n g e r , and in a n o r t h w e s t e r l y d i r e c t i o n . The P r o f i l e D environment was not so r e a d i l y apparent , and w i l l be d i s -cussed s h o r t l y . Severa l attempts have been made to measure beach d r i f t v e l o c i t i e s from t h i s type o f i n v e s t i g a t i o n , none o f which a re reaI Iy meaningfu I . Ing le (1966) measured the area between t r a c e r c o n c e n t r a t i o n contour s at d i f f e r e n t t imes dur ing the t i d a l c y c l e , to c a l c u l a t e t r a c e r d e p l e t i o n ra te s from h i s study a r e a . Wright (1962) drew a longshore s e c t i o n through h i s study area from the t r a c e r s ou r ce , and p l o t t e d t r a c e r p a r t i c l e counts on the s e c t i o n . Boon (1966) a l s o drew a longshore s e c t i o n , but p l o t t e d the t rend components i n s tead o f raw data v a l u e s . Both the l a t t e r p rocedures assumed that a zone o f h igh t r a c e r con -c e n t r a t i o n in a downdr i f t d i r e c t i o n rep re sen ted the "mode" o f t r a c e r p a r t i c l e movement. The present study has shown that 170. t h e s e " m o d e s " a r e a c t u a l l y r u n n e l s and b e a r no r e l a t i o n s h i p t o t h e l i t t o r a l d r i f t . At P r o f i l e D, s and t r a c e r s l o c a t e d s e a w a r d and l a n d -ward o f t h e g r a v e l f o r e s h o r e r e g i o n , b o t h m i g r a t e d i n a s o u t h -e a s t d i r e c t i o n . In t h e g r a v e l a r e a i t s e l f , g r a v e l t r a c e r s m i g r a t e d n o r t h w e s t w a r d s , and p e b b l e o r i e n t a t i o n m e a s u r e m e n t s i n d i c a t e d t h a t t h e s w a s h - b a c k w a s h a l s o moved i n a n o r t h w e s t d i r e c t i o n . T h i s c h a n g e i n d r i f t d i r e c t i o n w i t h t i d e l e v e l was v e r y l i k e l y a r e s u l t o f t h e n e a r s h o r e b a t h y m e t r y . The l o n g s h o r e b a r i n f r o n t o f P r o f i l e D, a l t h o u g h r e d u c e d t o a w i d e p l a t f o r m by t h e summer s t o r m ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) , was s e p a r a t e d f r o m Sand P o i n t by a b a t h y m e t r i c d e p r e s s i o n o f 6 - 8 f e e t (Map I ) . From m i d - t i d e u n t i l j u s t p r i o r t o h i g h t i d e , waves a p p r o a c h i n g t h i s r e g i o n w o u l d u n d e r g o a s h o a l i n g t r a n s f o r m a t i o n on t h e p l a t f o r m and Sand P o i n t , t h e r e b y c r e a t i n g a d i v e r g e n c e o v e r t h e b a t h y m e t r i c d e p r e s s i o n . T h i s wave d i v e r g e n c e p r e s u m a b l y , r e s u l t e d i n t h e n o r t h w e s t e r l y d r i f t a t P r o f i l e D, and a s o u t h e a s t e r l y d r i f t t o w a r d s Sand P o i n t . Be tween low t i d e and t h e m i d - t i d e l e v e l , waves s i m p l y b r o k e on t h e s e a w a r d edge o f t h e p l a t f o r m , and t h e e f f e c t s o f wave d i v e r g e n c e o v e r t h e b a t h y m e t r i c d e p r e s s i o n w o u l d be c o n c e n t r a t e d l o c a l l y on t h e f o r e s h o r e a d j a c e n t t o Sand P o i n t . Normal s o u t h e a s t e r l y d r i f t w o u l d p r e v a i l b e c a u s e o f t h e a n g u l a r r e l a t i o n s h i p b e t w e e n t h e b r e a k i n g waves and t h e p l a t f o r m . J u s t p r i o r t o h i g h t i d e , w a t e r d e p t h o v e r t h e p l a t -171. f o rm was p r o b a b l y j u s t t o o g r e a t t o h a v e any s h o a l i n g e f f e c t on t h e i n c o m i n g w a v e s , and norma l s o u t h e a s t e r l y d r i f t w o u l d a g a i n e n s u e . X. PLANIMETRIC SHAPE 172. A. INTRODUCTION To d a t e , r e l a t i v e l y l i t t l e e f f o r t has b e e n d i r e c t e d t o w a r d s a n a l y z i n g p l a n i m e t r i c s h a p e s o f b e a c h e s , w h e r e a s t h e l i t e r a t u r e i s w e l l d o c u m e n t e d w i t h i n v e s t i g a t i o n s i n t o t h e t o p o g r a p h i c c h a n g e s w h i c h o c c u r a l o n g t r a n s v e r s e p r o f i l e s . The r e a s o n f o r t h i s d i s p a r i t y i s due t o t h e f a c t t h a t c r o s s -s e c t i o n a l t o p o g r a p h i c v a r i a t i o n s r e s u l t f r o m s e v e r a l c y c l i c c h a n g e s i n t h e s e a c o n d i t i o n ( e . g . s e a s o n a l , 11 da I ) ; t h e y a r e r e l a t i v e l y r a p i d , and t h e r e f o r e e a s i l y f o l l o w e d . P l a n i m e t r i c c o n f i g u r a t i o n on t h e o t h e r h a n d , i s d i c t a t e d by an i r r e v e r s -i b l e p r o c e s s w h i c h becomes p r o g r e s s i v e l y s l o w e r as s t a b i l i t y i s a p p r o a c h e d , t h u s mak ing measurement o f i t s t i m e d e v e l o p " ment more d i f f i c u l t . An embayed c o a s t l i n e w i l l d e v e l o p w h e r e v e r u n c o n -s o l i d a t e d s e d i m e n t s e p a r a t e s two r e s i s t a n t h e a d l a n d s . The p l a -n i m e t r i c shape o f t h e embayment d e p e n d s p r i n c i p a l l y on t h e a n g u l a r a p p r o a c h o f s w e l l t o w a r d s t h e c o a s t l i n e - when i t i s p a r a l l e l , b e a c h e s s t a b i l i z e i n a c i r c u l a r a r c p l a n ( M c L e a n , 1967), and when i t a p p r o a c h e s o b l i q u e l y , as a t Wreck B a y , a c h a r a c t e r i s t i c s h a p e o f d i f f e r e n t g e o m e t r i c d i m e n s i o n s i s f o r m e d . S i l v e s t e r (I960) ha s named t h e l a t t e r " h a l f - h e a r t s h a p e d b a y s " , and Y a s s o (1964) " h e a d l a n d - b a y b e a c h e s " . The l a t t e r t e r m i s p r e f e r r e d , and i s d e f i n e d by Y a s s o as f o l l o w s : 173. " . . . t h e h e a d l a n d - b a y b e a c h c h a r a c t e r i s t i c a l l y has a s e a w a r d - c o n c a v e p l a n s h a p e , i n w h i c h t h e r a d i u s o f p l a n c u r v a t u r e becomes g r e a t e r w i t h i n c r e a s i n g d i s t a c e f r om t h e h e a d l a n d , " The c o a s t l i n e i n v i c i n i t y o f Wreck Bay i s o r i e n t e d a t a p p r o x i -m a t e l y 1 3 0 ° , and d e e p - w a t e r s w e l l f r o n t s , as m e a s u r e d f r om a e r i a l p h o t o g r a p h s , a v e r a g e 180° ( T a b l e I I I ) , The bay has d e -v e l o p e d i n r e s p o n s e t o wave d i f f r a c t i o n a r o u n d t h e h e a d l a n d s , wave r e f r a c J o n a l o n g i t s s h o a l i n g b o t t o m , and wave r e f l e c t i o n f r om F l o r e n c i a I s l a n d and S e a l Rock ( F i g . 4 0 ) . E x a m i n a t i o n o f t h e s h a p e o f Wreck Bay (Map I) imme-d i a t e l y s u g g e s t s c o n f o r m i t y b e t w e e n t h e s h o r e l i n e i n t h e n o r t h -west h a l f o f t h e b a y , and t h e s h a p e o f a h e a d l a n d - b a y b e a c h . The s o u t h e a s t h a l f a p p e a r s s i m i l a r t h o u g h l e s s w e l l d e v e l o p e d , and i s o r i e n t e d i n t h e o p p o s i t e d i r e c t i o n r e l a t i v e t o t h e h e a d -l a n d (Wya P o i n t ) , t h a t i s , c o u n t e r c l o c k w i s e , B o t h h a l v e s a r e n a t u r a l l y s e p a r a t e d by Sand P o i n t , w h i c h e x t e n d s s e a w a r d f rom t h e m i d d l e o f t h e b a y . I t was d e c i d e d t o t e s t b o t h h a l v e s a g a i n s t l o g - s p i r a l c u r v a t u r e , and f u r t h e r m o r e , t o t e s t a num-b e r o f s e c t i o n s w i t h i n e a c h h a l f , i n o r d e r t o e x a m i n e t h e i n -f l u e n c e o f t h e l a t t e r on t h e s p i r a l p a r a m e t e r s . B. PLAN DATA ACQU IS IT lON P l a n d a t a was o b t a i n e d f r om t h e b e a c h s u r v e y c a r r i e d o u t i n A u g u s t 1968. S i n c e o n e o f t h e o b j e c t i v e s o f t h i s s t u d y was t o d e t e r m i n e where c l i f f r e c e s s i o n had e x c e e d e d o r l a g g e d f r o m t h e o r e t i c a l l o g - s p i r a l c u r v a t u r e , t h e b a s e o f t h e c l i f f was u s e d f o r d e m a r c a t i o n o f t h e c o a s t l i n e . A t o t a l o f 73 r o d * The method e m p l o y e d f o r h o r i z o n t a l c o n t r o l , s e e h e a d i n g TOPOGRAPHY OF WRECK BAY 1 7 4 . s t a t i o n s were s u r v e y e d a l o n g t h e c l i f f b a s e , 4 9 f o r t h e n o r t h -wes t h a l f , and 2 4 f o r t h e s o u t h e a s t h a l f o f t h e b a y . The rod s t a t i o n s were p l o t t e d on a c a r t e s i a n g r i d w i t h a s c a l e o f ! i n c h = 200 f e e t . The g r i d wa s o r i e n t e d so t h a t t h e o r d i n a t e c o i n c i d e d w i t h g e o g r a p h i c n o r t h and l a y t a n -g e n t i a l t o t h e n o r t h w e s t c o r n e r o f t h e b a y , and t h e a b s c i s s a was f i x e d t a n g e n t i a l t o t h e s o u t h e a s t c o r n e r o f P o c k e t B e a c h . Each s t a t i o n was t h e n a s s i g n e d ( x , y ) c o o r d i n a t e s f r om t h e g r i d , w h i c h were a c c u r a t e l y s c a l e d t o 5 f e e t , and e s t i m a t e d t o t h e n e a r e s t o n e f o o t . C. DEF IN IT ION OF A LOGARITHMIC S P l K A L An e q u i a n g u l a r o r l o g a r i t h m i c s p i r a l i s e x p r e s s e d by t h e e q u a t i o n : ^ 9coto6 . . P = e ( I ) where l e n g t h o f t h e r a d i u s v e c t o r e = b a s e o f n a t u r a l l o g a r i t h m 0 = a n g l e b e t w e e n r a d i u s v e c t o r and a d e f i n e d a z i m u t h 06 = s p i r a l a n g l e , m e a s u r e d b e t w e e n t h e r a d i u s v e c t o r and a t a n g e n t drawn t o t h e c u r v e a t t h a t p o i n t . I t i s a c o n s t a n t f o r any g i v e n l o g - s p i r a l . F o r t h e s p i r a l n o m e n c l a t u r e u s e d h e r e , s e e i n s e t i n F i g u r e 40 . E q u a t i o n ( I ) c a n be r e w r i t t e n a s : I n/>= 9 c o t 06 (2) w h i c h a l l o w s p l o t t i n g o f /O vs 9 on s e m i - l o g p a p e r as a s t r a i g h t l i n e . V i s u a l i n s p e c t i o n o f p l a n d a t a d e v i a t i o n f r om t h i s 175. r e g r e s s i o n l i n e i s now p o s s i b l e as shown in F i gu re s 4 l a , b, c , D. TEST PROCEDURE The methods used in t h i s s tudy a re e s s e n t i a l l y the same as those d e v i s e d by Yasso (1364). The procedure i n v o l v e s s e l e c t i n g an a r b i t r a r y l o g - s p i r a l c e n t e r , and t e s t i n g the c u r -ve generated there f rom aga in s t the p l an data as f o l l o w s : The p l an data c a r t e s i a n c o o r d i n a t e s a re i n i t i a l l y conve r ted to p o l a r c o o r d i n a t e s us ing the f o l l o w i n g t r a n s f o r m a t i o n equat i ons : r, = Ju} ~ X ) 2 + (y, - Y ) 2 (3 ) y. - Y 9; = arc tan -—z~j (4) i where ( x j , y j ) = c a r t e s i a n c o o r d i n a t e s o f the p l an data (X,Y) = c a r t e s i o n c o o r d i n a t e s o f the a r b i t r a r y log-spi ra I c e n t e r . By the method o f leas t squares , the best f i t t i n g s t r a i g h t l i n e to ( 0 . , log r.) f o r a l l i i s determined. The equat ion o f the s t r a i g h t l i n e i s o f the form lnyO= aO + b (5) and so by m i n i m i z i n g the f u n c t i o n N 5 0n r i • ( a e + b l 2 _ _ _ _ _ _ _ _ . (6) N con s t an t s a and b a re found: a = N I ( e . . l n r.) - £ Q . . £ l n r. ( ? ) HIQ.2 - (10. ) 2 176. 2 , £ 9 . . In r. - £ 0 . . l ( 0 . . l n r. ) 2 2 N £ 0 . - ( 1 0 . ) i i ( T h e s e a r e shown on t h e s e m i - l o g p l o t s d e p i c t e d i n F i g u r e s 4 1 a , b , c and 4 2 a , b, c . ) The mean s q u a r e d e r r o r b e t w e e n a c t u a l r a d i u s v e c t o r s r j , and t h e c o r r e s p o n d i n g t h e o r e t i c a l r a d i u s v e c t o r s p- , a r e t h e n c a l c u l a t e d f o r e a c h 0. by means o f : N a 0 ; + b r. - e i (9) ,N By e m p l o y i n g a s e a r c h s q u a r e p r o c e d u r e , a l o g - s p i r a l i s e v e n t u a l l y f o u n d whose mean s q u a r e d e r r o r i s a min imum. The s p i r a l a n g l e o f t h i s b e s t f i t t i n g c u r v e i s d e t e r m i n e d by means o f : d = a r c t a n ( ' / a ) (10 ) E. COMPUTER TECHNIQUE A p r o g r a m w r i t t e n by P. L e B l o n d and J .W i I son was u s e d f o r e v a l u a t i n g p l a n d a t a on an IBM 3 6 0 / 6 7 computer. . The t e c h n i q u e e m p l o y e d was as f o l l o w s : A s i n g l e l o g - s p i r a i c e n t e r was a r b i t r a r i l y c h o s e n and s u p p l i e d t o t h e p r o g r a m , a r o u n d w h i c h was c r e a t e d a f a i r l y l a r g e s e a r c h s q u a r e - i n t h e o r d e r o f 50 s q . f t . The s e a r c h s q u a r e was ;made up o f 25 c e n t e r s . , e a c h o f w h i c h was t e s t e d i n -d e p e n d e n t l y a g a i n s t t h e c u r v a t u r e o f t h e c l i f f b a s e . A r o u n d t h e o n e w i t h l e a s t mean s q u a r e d e r r o r was c r e a t e d a s e c o n d s e a r c h 177. s q u a r e w i t h t h e same d i m e n s i o n s . T h i s p r o c e s s c o n t i n u e d u n t i l a c e n t e r was f i n a l l y l o c a t e d whose e r r o r was a min imum. The s e a r c h s q u a r e was t h e n r e d u c e d t o 1/5 o f i t s o r i g i n a l s i z e , and t h e p r o c e d u r e r e p e a t e d . When t h e s e a r c h s q u a r e d i m e n s i o n s were e v e n t u a l l y r e d u c e d t o l e s s t h a n I s q . f t . t h e p r o g r a m was t e r -mi n a t e d . C o m p u t e r p r i n t o u t i n c l u d e d c a r t e s i a n c o o r d i n a t e s f o r t h e b e s t f i t t i n g l o g - s p i r a l c e n t e r , r o o t mean s q u a r e d e r r o r b e t w e e n t h e a c t u a l and t h e o r e t i c a l r a d i u s v e c t o r s , a t a b u l a -t i o n o f t h e s e r a d i u s v e c t o r s f o r N0 v a l u e s , and t h e a and b r e g r e s s i o n l i n e c o n s t a n t s . A s u b - r o u t i n e was a l s o w r i t t e n t o p l o t t h e r e g r e s s i o n l i n e s shown i n F i g u r e s 4 l a , b , c and 4 2 a , b , c by a C a l c o m p P l o t t e r a t t a c h e d t o t h e c o m p u t e r . As an i n d i c a t i o n o f t h e e f f c i e n c y o f t h i s p r o g r a m , l e s s t h a n 3/4 h o u r o f c o m p u t e r t i m e was r e q u i r e d t o l o c a t e 6 b e s t f i t t i n g l o g - s p i r a l c e n t e r s , and t o p l o t t h e i r r e s p e c t i v e r e g r e s s i o n l i n e s . Y a s s o ( 1 9 6 4 ) , w i t h a s i m i l a r s t u d y p e r f o r m e d on s p i t b a r s , r e q u i r e d 260 h o u r s t o l o c a t e 33 s p i r a l c e n t e r s , u s i n g IBM 1620 and IBM 7090 c o m p u t e r s . F. DESCRIPTION OF BEACH SECT iONS STUDIED  I. NORTHWEST HALF OF WRECK BAY - C I i f f b a s e a t LSC - The c l i f f s e c t i o n e x t e n d s f r o m Q u i s i t i s P o i n t t o Sand P o i n t . 7 P l a n d a t a p o i n t s a r e l o c a t e d a t t h e c l i f f b a s e b e h i n d L o s t Shoe C r e e k . The b e s t f i t t i n g l o g -s p i r a l c u r v e i s shown as d a s h e d l i n e i n F i g u r e 4 0 , and t h e 173.. c e n t e r i s marked by a t r i a n g l e . S p i t c r e s t at LSC - Th i s c l i f f s e c t i o n a l s o extends from Q u i s i t i s Po in t to Sand P o i n t . The 7 p l an data p o i n t s l o ca ted at the c l i f f b a s e behind Lost Shoe Creek have been exchanged f o r 7 p o i n t s a long s p i t b a r c r e s t . The best f i t t i n g l o g - s p i r a l c e n t e r i s marked by a c i r c l e in F i g u r e 40. - NW Corner - Extends from Q u i s i t i s Po in t to the mouth o f Lost Shoe Creek. The bes t f i t t i n g l o g - s p i r a l c e n t e r i s marked by a c i r c l e in F i g u r e 40. 2. SOUTHEAST HALF OF WRECK BAY - SE Pocket Beach - Th i s c l i f f s e c t i o n extends from the southeas t c o r n e r o f Pocket Beach to Sand P o i n t . The bes t f i t t i n g l o g - s p i r a l cu rve i s shown as dashed l i n e in F i g u r e 40, and the c e n t e r i s marked by a t r i a n g l e , " SE Corner ( I) - The c l i f f s e c t i o n extends from the sou th -east c o r n e r o f Wreck Bay to Sand P o i n t . The best f i t t i n g l o g - s p i r a l c e n t e r i s marked by a c i r c l e in F i g u r e 40. " SE Corner (2) - Same as SE Corner ( I ) . Parameters o f the best f i t t i n g l o g - s p i r a l curves to these s e c t i o n s a re shown in Tab le XVI I , and where a v a i l a b l e , those from Yasso (1964) have been i n c l u d e d f o r compar i son. G. RESULTS I. NORTHWEST HALF OF WRECK BAY Examinat ion o f the p l o t s o f F i gu re s 41a, 4 l b , and 179. 41c c l e a r l y i l l u s t r a t e the e x c e l l e n t f i t between p l an data and t h e o r e t i c a l l o g - s p i r a l s . The dashed curve shown in F i gu re 40 ( C l i f f b a s e at LSC) has the g r e a t e s t root mean squared e r r o r o f the t h r e e t e s t s made in the northwest h a l f o f the bay, and yet the l o g - s p i r a l f i t i s s t i l l very good. By exchanging 7 c l i f f b a s e p o i n t s f o r 7 s p i t c r e s t p o i n t s , the root mean squared e r r o r decreased from 92.02 feet to 69.09 fee t i n d i c a t i n g improved l o g - s p i r a l c u r v a t u r e . F u r t h e r -more, the s p i r a l ang le decreased in s i z e (Tab le XV I I ) , and the s p i r a l c e n t e r moved towards the headland and beach (northwest di rect i o n ) . For the t h i r d t e s t (NW C o r n e r ) , the root mean squared e r r o r decreased s t i l l f u r t h e r to 31.02 f e e t , the s p i r a l ang le was reduced, and the s p i r a l c e n t e r moved c l o s e r towards the headland and beach. The improved f i t o f t h i s c l i f f s e c t i o n i s due to i t s s h o r t e r l eng th . It i n v o l v e s fewer data p o i n t s than the o t h e r two t e s t s , and t h e r e f o r e i n c o r p o r a t e s fewer l o c a l d i s t o r t i o n s i n to the c a l c u l a t i o n s . 2. SOUTHEAST HALF OF WRECK BAY The computer program was a l t e r e d here to genera te l o g - s p i r a l curves in a c o u n t e r c l o c k w i s e d i r e c t i o n , that i s , the m i r r o r image o f the s p i r a l nomenclature diagram shown in the i n s e t o f F i g u r e 40. It i s i n t e r e s t i n g to note that the 4 beaches s t u d i e d by Yasso (1964) on both the east and west c o a s t s o f the U n i t e d S t a t e s , the 6 beaches mentioned by 180. S i l v e s t e r ( I 9 6 0 ) a l o n g t h e e a s t c o a s t o f S o u t h A f r i c a , and t h e n o r t h w e s t h a l f o f Wreck B a y , a r e a l l c l o c k w i s e s p i r a l s . T h e s e a r e a s a r e a l l a f f e c t e d by waves w h i c h a p p r o a c h t h e c o a s t l i n e s on t h e same s i d e . E x a m i n a t i o n o f t h e p l o t s o f F i g u r e s 4 2 a , 42b and 42c shows t h a t o n l y p o o r c o r r e s p o n d e n c e b e t w e e n t h i s h a l f o f Wreck Bay and l o g - s p i r a l c u r v a t u r e e x i s t s . The d a s h e d c u r v e shewn i n F i g u r e 40 (SE P o c k e t B e a c h ) has a v e r y l a r g e r o o t mean s q u a r e d e r r o r , and i t s d e p a r t u r e f r o m t h e c l i f f b a s e i s s e e n t o be g r o s s . A l a r g e d e p a r t u r e i s e v i d e n t s o u t h e a s t o f Sand P o i n t where t h e c l i f f f a c e c o n s i s t s o f e x p o s e d g l a c i o f l u v i a l o u t w a s h ( F i g u r e 4 0 ) . T h i s a r e a i s m a r k e d b y - a n i n c i p i e n t c u s p a t e f o r e -l a n d ( s e e c h a p t e r o n BEACH STRUCTURES ) , and c a n be s e e n i n F i g u r e 2 as a s l i g h t l y c o n v e x s e a w a r d p o r t i o n o f t h e c l i f f -b a s e . The f a c t t h a t t h e s p i r a l a n g l e o f t h i s c u r v e i s s m a l l , and t h a t i t s s p i r a l c e n t e r i s c l o s e t o t h e h e a d l a n d , a p p e a r s t o c o n t r a d i c t e a r l i e r o b s e r v a t i o n s made f o r t h e n o r t h w e s t h a l f o f Wreck Bay . In r e a l i t y , c o m p a r i s o n o f t h e s p i r a l p a r a m e t e r s o f d i f f e r e n t b e a c h e s i s no t a v a l i d p r o c e d u r e , s i n c e t h e h y d r o d y n a m i c e n v i r o n m e n t a t e a c h l o c a t i o n i s no t t h e same. I t i s b e l i e v e d t h a t were t h e c l i f f b a s e t o a p p r o a c h l o g - s p i r a l c u r v a t u r e more c l o s e l y f o r t h i s h a l f o f t h e b a y , t h e s p i r a l a n g l e w o u l d d e c r e a s e f u r t h e r , and t h e s p i r a l c e n t e r w o u l d move c l o s e r t o t h e h e a d l a n d . The f i n a l c l i f f s e c t i o n t e s t e d (SE C o r n e r ) 1 3 1 . u n e x p e c t e d l y y i e l d e d two s p i r a l c e n t e r s , t h u s i n d i c a t i n g t h a t f o r v e r y p o o r l y f i t t i n g c u r v e s t h e r e may be no u n i q u e s o l u t i o n . They were f o u n d by s u p p l y i n g t h e c o m p u t e r a t d i f f e r e n t t i m e s w i t h c e n t e r s l o c a t e d a t w i d e l y s e p a r a t e p o i n t s . F o r ( I ) t h e f i r s t c u r v e o b t a i n e d , t h e r o o t mean s q u a r e d e r r o r i s v e r y l a r g e v i z . 196,02 f e e t , t h e s p i r a l a n g l e i s v e r y s m a l l , and t h e s p i r a l c e n t e r i s v i r t u a l l y a d j a c e n t t o t h e h e a d l a n d . T h i s l o g - s p i r a l c u r v e o p e n s r a p i d l y and i s c o n t r o l l e d m a i n l y by d a t a p o i n t s l o c a t e d a l o n g t h e " e l b o w " o f t h e c l i f f s e c t i o n ( n e a r Wya P o i n t ) , F o r ( 2 ) , t h e r o o t mean s q u a r e d e r r o r i m p r o v e d somewhat t o 143.96 f e e t , t h e s p i r a l a n g l e became v e r y l a r g e , and t h e s p i r a l c e n t e r i s l o c a t e d more t h a n a m i l e away f r o m t h e h e a d l a n d and b e a c h . T h i s l o g - s p i r a l c u r v e t h u s o p e n s s l o w -l y , p r o b a b l y t u r n i n g a b o u t t h e c e n t e r a t l e a s t o n c e b e f o r e c o -i n c i d i n g w i t h t h e c l i f f s e c t i o n , and d a t a p o i n t s l o c a t e d a l o n g t h e " a r m " ( n e a r Sand P o i n t ) b e a r s t r o n g e r i n f l u e n c e on t h e c u r v e s p o s i t i o n . Were t h e c l i f f b a s e o f t h i s s e c t i o n t o a p p r o a c h l o g - s p i r a l c u r v a t u r e more c l o s e l y , a u n i q u e s p i r a l c e n t e r w o u l d d e v e l o p w h i c h , as n o t e d e a r l i e r , w o u l d move t o w a r d s h e a d l a n d and b e a c h as t h e f i t i m p r o v e d s t i l l f u r t h e r . H. INFERENCES FKOM 6LAC IOFLUV IAL OUTWASH EXPOSED C L I F F SECTIONS W i t h r e f e r e n c e t o F i g u r e s 4 0 , 4 1 a , b , c and 4 2 a , b , c , i t i s a p p a r e n t t h a t a p p r o x i m a t e l y h a l f o f t h e c l i f f f a c e c o n -s i s t s o f e x p o s e d g l a c i o f l u v i a l o u t w a s h , t h e r e s t b e i n g d e n s e l y c o v e r e d w i t h u n d e r b r u s h and l a r g e t r e e s . The age o f t h e s e 182. t r e e s , some o f w h i c h grow a t t h e c l i f f b a s e , a r e e s t i m a t e d a t c l o s e t o 200 y e a r s o l d , t h u s i n d i c a t i n g t h e q u a s i - p e r m a n e n c e o f t h e s e c l i f f s e c t i o n s . C l i f f s e c t i o n s e x p o s i n g g I a c i o f I u v i a I o u t w a s h a r e g e n e r a l l y s e a w a r d o f t h e l o g - s p i r a l c u r v e s , and t i m b e r e d s e c t i o n s a r e g e n e r a l l y l a n d w a r d o f t h e c u r v e s , t h u s s u g g e s t i n g t h a t c l i f f e r o s i o n i s p r e s e n t l y a c t i v e i n a r e a s t h a t w o u l d b r i n g t h e two h a l v e s o f Wreck .Bay c l o s e r t o l o g - s p i r a l c u r v a t u r e . A n o t h e r p o i n t t o n o t i c e i n F i g u r e 4 0 , i s t h a t g l a c i o -f l u v i a l o u t w a s h i s g e n e r a l l y e x p o s e d i n c l i f f s e c t i o n s w h i c h f a c e t h e open o c e a n . T h e s e a r e a s a r e d i r e c t l y e x p o s e d t o s t r o n g m o i s t u r e - I a d e n w i n d d u r i n g t h e w i n t e r m o n t h s , s u g g e s t i n g t h a t t h i s i s t h e a g e n t r e s p o n s i b l e f o r c l i f f e r o s i o n a t t h e p r e s e n t t i m e . In s u p p o r t o f t h i s c o n t e n t i o n i s t h e f a c t t h a t nowhere was c l i f f u n d e r c u t t i n g t h r o u g h wave a c t i o n e v i d e n t i n F e b r u a r y 1969 ( s e e c h a p t e r on TRANSVERSE P R O F I L E S ) , wherea s numerous s m a l l l a n d s l i d e s c o u l d be h e a r d r a t t l i n g down t h e c l i f f f a c e e v e r y few m i n u t e s . S a t u r a t i o n o f t h e g I a c i o f I u v i a I o u t w a s h by w i n d - d r i v e n r a i n w o u l d i n c r e a s e t h e p o r e - w a t e r p r e s -s u r e and d e c r e a s e c o h e s i o n b e t w e e n t h e s e d i m e n t a r y p a r t i c l e s , t h e r e b y p r o m o t i n g t h e s m a l l l a n d s l i d e s . I t seems a p p a r e n t t h e r e f o r e t h a t t h e c l i f f b a s e a t Wreck Bay has been s t a b l e f o r a r e l a t i v e l y l ong t i m e and t h a t i t s p l a n i m e t r i c shape i s c l o s e t o e q u i l i b r i u m w i t h t h e p r e v a i l i n g h y d r o d y n a m i c e n v i r o n m e n t . L i m i t e d e r o s i o n o f * See GLOSSARY 183. t h e c l i f f seems t o o c c u r as a r e s u l t o f s a t u r a t i o n by m o i s t u r e -l a d e n w i n d , and t h i s i s c o n f i n e d t o a r e a s where r e t r e a t o f t h e c l i f f w o u l d b r i n g t h e p l a n i m e t r i c s h a p e o f t h e two h a l v e s o f Wreck Bay c l o s e r t o l o g - s p i r a l c u r v a t u r e . I. THE EFFECT OF WAVES AND CURRENTS IN THE DEVELOPMENT  OF HEADLAND-BAY BEACHES The r e l a t i v e i m p o r t a n c e o f r e f r a c t e d , d i f f r a c t e d and r e f l e c t e d waves i n s c u l p t u r i n g t h e g e o m e t r y o f h e a d l a n d -bay b e a c h e s i s unknown. I t i s a p p a r e n t h o w e v e r , t h a t t h e " a r m " s e c t i o n o f a h e a d l a n d - b a y b e a c h t e n d s t o a l i g n i t s e l f p a r a l l e l t o waves w h i c h h a v e been s i m p l y r e f r a c t e d i n t h e s h o a l i n g b a y . The " e l b o w " s e c t i o n on t h e o t h e r h a n d , i s s u b j e c t e d t o t h e c o m b i n e d e f f e c t s o f b o t h wave d i f f r a c t i o n a r o u n d t h e h e a d l a n d , and wave r e f r a c t i o n on t h e s h o a l i n g b o t t o m . L e M e h a u t e and B r e b n e r (1961) h a v e i n d i c a t e d t h e p r e s e n c e o f a " d i f f r a c t i o n c u r r e n t " l e e w a r d o f a h e a d l a n d , and s t a t e t h a t " . . . a c u r r e n t a l w a y s e x i s t s f r o m a h i g h wave r e g i o n t o a low wave r e g i o n " . T h i s phenomenon i s s i m i l a r t o l i g h t d i f f r a c t i o n a r o u n d an o b j e c t , r e s u l t i n g i n a penumbra z o n e . The e x i s t e n c e o f s u c h a c u r r e n t a t Wreck Bay i s i n d i c a t e d by two f e a t u r e s : The s p i t b a r i n f r o n t o f L o s t Shoe C r e e k p o i n t s n o r t h w e s t -wards t o w a r d s Q u i s i t i s P o i n t (Map I ) . Sand i n s u s p e n s i o n i s c a r r i e d f r o m t h e n e a r s h o r e z o n e i n t h e " e l b o w " , o u t t o w a r d s Q u i s i t i s P o i n t ( s e e F r o n t i s p i e c e ) . The s and i s i n i t i a l l y p u t i n t o s u s p e n s i o n by t u r b u l e n c e 184. c r e a t e d by vv~v.es i m p i n g i n g a g a i n s t t h e b o u l d e r bed i n t h i s a r e a (Map I ). Opposed t o t h i s n e a r s h o r e d i f f r a c t i o n c u r r e n t , a f o r e s h o r e l i t t o r a l c u r r e n t a l w a y s moves i n t h e o p p o s i t e d i r e c t i o n , t h a t i s , f r om Q u i s i t i s P o i n t t o w a r d s L o s t Shoe C r e e k ( s e e c h a p t e r on SAND MOVEMENT BASED ON WAVE PARAMETERS). T h i s s u g g e s t s t h a t a c i r c u l a r c u r r e n t c l o s e t o s h o r e may be r e s p o n s i b l e f o r s c u l p t u r i n g t h e a r e a l e e w a r d o f Q u i s i t i s P o i n t . S y l v e s t e r ( I 9 6 0 ) c o n d u c t e d a model t a n k s t u d y on s h o r e l i n e e r o s i o n , and assumed " e q u i I ibr ium" o f a h a l f - h e a r t s h a p e d bay t o e x i s t when a s i n g l e wave b r o k e s i m u l t a n e o u s l y a r o u n d t h e w h o l e l e n g t h o f t h e b a y . F o r t h i s a s s u m p t i o n t o be v a l i d , b a t h y m e t r i c c o n t o u r s w o u l d have t o be c o n c e n t r i c b e t w e e n h e a d l a n d s , and e a c h o n e w o u l d h a v e t o p o s s e s s l o g -s p i r a l c u r v a t u r e . T h e s e f e a t u r e s a r e no t a p p a r e n t a t Wreck B a y , b u t e x a m i n a t i o n o f t h e f i r s t d i a g r a m i n S y l v e s t e r ' s ( I 9 6 0 ) p a p e r r e v e a l s t h a t t h e r a t e o f e r o s i o n d e c r e a s e s s i g n i f i c a n t l y as t h e bay a p p r o a c h e s p l a n i m e t r i c e q u i I i b r i um. T h i s o b s e r v a -t i o n c o n f i r m s t h e e q u i l i b r i u m s t a t u s a r r i v e d a t e a r l i e r f o r Wreck Bay . J . GENERAL RELATIONSHIPS BETWEEN BAY GEOMETRY AND  LOG-SP IRAL PARAMETERS F o r t h e n o r t h w e s t h a l f o f Wreck Bay i t was f o u n d t h a t t h e p l a n i m e t r i c s h a p e a p p r o a c h e d l o g - s p i r a l c u r v a t u r e more c l o s e l y as t h e s p i r a l p a r a m e t e r s u n d e r w e n t t h e f o l l o w i n g c h a n g e s : 185. - The r o o t mean s q u a r e d e r r o r d e c r e a s e d , The s p i r a l a n g l e d e c r e a s e d . The s p i r a l c e n t e r moved i n t o w a r d s t h e h e a d l a n d and b e a c h . C l i f f s e c t i o n s e x a m i n e d i n t h e s o u t h e a s t h a l f o f Wreck Bay d e v i a t e d m a r k e d l y f r om l o g - s p i r a l c u r v a t u r e , and t h e s p i r a l p a r a m e t e r s were u n p r e d i c t a b l e . At t h e end o f t h e H o l o c e n e ' T r a n s g r e s s ijon, F l o r e n c i a I s l a n d p r e s u m a b l y c o n s t i t u t e d t h e u p c o a s t h e a d l a n d f o r a c l o c k w i s e h e a d l a n d - b a y b e a c h i n a s o u t h e a s t d i r e c t i o n and s u b s e q u e n t l y , S e a l Rock became t h e u p -c o a s t h e a d l a n d . A l t h o u g h b o t h a r e i s o l a t e d f r o m t h e c o a s t t o -d a y , t h e y s t i l l h a v e a p r o f o u n d e f f e c t on t h e m o r p h o l o g y o f t h e s o u t h e a s t p o r t i o n o f t h e b a y . I f t h e y were s u d d e n l y r e -moved , t h e s o u t h e a s t p o r t i o n w o u l d p r o g r a d e u n t i l Wya P o i n t became t h e downcoa s t h e a d l a n d o f a s i n g l e h e a d l a n d - b a y b e a c h o c c u p y i n g t h e w h o l e o f Wreck Bay . In c o n c l u s i o n , t h e f o l l o w i n g remark s on bay g e o -m e t r y and s p i r a l p a r a m e t e r s seem a p p r o p r i a t e . They were d e r i v e d a t f r o m l o g i c a l r e a s o n i n g , and t h e i r v a l i d i t y r e q u i r e s t e s t i n g i n a mode I t a n k : The e q u i l i b r i u m p o s i t i o n o f t h e s p i r a l c e n t e r , and t h e v a l u e o f t h e s p i r a l a n g l e , d e p e n d s on two f a c t o r s : The d i s t a n c e b e t w e e n h e a d l a n d s , and t h e a n g l e b e t w e e n p r e v a i l i n g d e e p - w a t e r wave f r o n t s and t h e c o a s t l i n e . Knowing t h e s e two f a c t o r s , c a l c u l a t i o n o f an e q u i l i b r i u m p l a n i m e t r i c s h a p e f o r an embayed c o a s t l i n e s h o u l d be p o s s i b l e . F u r t h e r m o r e , i f 186. s p i r a l p a r a m e t e r s c h a n g e s e q u e n t i a l l y as t h e c o a s t l i n e a p p r o a c h e s p l a n i m e t r i c e q u i l i b r i u m , t h e n v a l i d p r e d i c t i o n s on c o a s t a l m u t a t i o n s h o u l d be p o s s i b l e . I f two h e a d l a n d s a r e s e p a r a t e d by u n c o n s o l i d a t e d s e d i m e n t , t h e d o w n c o a s t o n e w i l l l i m i t t h e d e p t h o f c o a s t a l embay-ment s i n c e l i t t o r a l d r i f t p a s t i t w i l l c e a s e when t h e " a r m s e c t i o n i s p a r a l l e l t o t h e r e f r a c t e d waves i n t h e b a y . I f o n l y o n e h e a d l a n d e x i s t s , d o w n c o a s t embayment w i l l p r o -g r e s s u n t i l i t s l o g - s p i r a l c u r v a t u r e " c a p t u r e s " t h e u p -c o a s t s e c t i o n , and t h e h e a d l a n d becomes i s o l a t e d f r o m t h e c o a s t as an i s l a n d . 187. L o c a t i o n N o „ o f A p p r o x . C a r t e s i o n p l a n i e n g t h c o o r d i n a t e s d a t a o f o f l o g - s p i r a i p o i n t s j s e c t i o n j c e n t e r ( f e e t ) (mi I e s ) I X I Y App r o x . * d i s t a n c e o f c e n t e r t o h e a d -l a n d ( f t ) Sp ! r a I ang I e ( d e -g r e e s ) Root mean s q u a r e d e r r o r ( f e e t ) NORTHWEST HALF 0 C I i f f b a s e a t LSC Sp i t c r e s t a t LSC NW C o r n e r SE P o c k e t b e a c h SE C o r n e r ( I ) SE C o r n e r (2) 49 49 24 2k 20 20 I 3/k I 3/k 3/k i I 1/2 I \/k I \/k 7 I 2 0 0 6 2 4 . 0 5 2 6 . 7 7 6 3 6 . 0 7 7 4 4 , 0 7 9 1 9 . 8 WRECK BAY 320 290 280 5 3 . 18 5 1 . 0 2 4 8 . 7 7 SOUTHEAST HALF OF WRECK BAY 9 9 6 3 . 7 I 1203.0 5 2 9 4 . 4 287 .5 1358-2 -820.8 10 10 5500 4 4 . 0 2 24 .53 81.96 9 2 . 0 2 6 9 . 0 9 3 1 . 0 2 193.78 196.02 143. Sp i ra I B e a c h , New j e r s e y Ha I fmoon B a y , Ca I i f o r n i D r a k e s B e a c h , C a l i f o r n i a L i mantou r Sp i t , Ca I i f o r n i a Y a s s o (1964) 22 57 20 24 1/2 10 250 3000 14000 6 1 . 4 9 4 1 . 2 6 8 5 . 6 4 8 2 . 2 0 .82 183.7 16. I 2 3 4 . 4 * T h i s measurement was o b t a i n e d by s c a l i n g t h e d i s t a n c e b e t w e e n l o g - s p i r a l c e n t e r s and t h e n e a r e s t h e a d l a n d . S m a l l r o c k i s l a n d s a d j a c e n t t o t h e h e a d l a n d s p r o p e r a r e o f r e l a t i v e l y m i n o r i m p o r t a n c e , and were t h e r e f o r e no t c o n s i d e r e d . T a b l e XVI I P a r a m e t e r s o f B e s t F i t t i n g L o g - S p i r a l C u r v e s and O t h e r P e r t i n e n t I n f o r m a t i o n . F i g u r e 4 0 . P l a n i m e t r i c s h a p e o f Wreck Bay and f i t t e d l o g - s p i raI c u r v e s . - The l o g - s p i r a l c u r v e s shown as d a s h e d l i n e s , a r e f o r C l i f f b a s e a t L o s t Shoe C r e e k and S o u t h e a s t P o c k e t B e a c h , and t h e i r c e n t e r s a r e shown by s m a l l t r i a n g l e s . O t h e r s p i r a l c e n t e r s a r e i n c i -c a t e d by s m a l l c i r c l e s . - The s p i t b a r c r e s t i s shown as a d o t t e d l i n e , and c l i f f s e c t i o n s e x p o s i n g g I a c i o f I u v i a I o u t w a s h , as d o t t e d s t r i p s . - S p i r a l n o m e n c l a t u r e u s e d i n t h e t e x t i s shown i n t h e i n s e t . FIGURE 40 F i g u r e s 4 1 a , b , c . R e g r e s s i o n l i n e p l o t s o f t h r e e l o g - s p i r a l c u r v e s t e s t e d i n t h e n o r t h w e s t h a l f o f Wreck Bay . - R a d i u s v e c t o r / 0 i s p l o t t e d on a l o g a r i t h m i c s c a l e , and a r c 9 on an a r i thmet i c s ea Ie. - C o n s t a n t s a and b a r e i n d i c a t e d i n t h e r e -g r e s s i o n l i n e e q u a t i o n s o f e a c h d i a g r a m . - C l i f f s e c t i o n s e x p o s i n g g I a c i o f I u v i a I o u t w a s h a r e i n d i c a t e d by d o t t e d s t r i p s . N.W HALF OF WRECK BAY 189 — I I i I. CLIFF-DflSe RT L .S .C 6000-sooc -4000-3000 -2500-2000 -1500 -1000 -F I G U R E 4 1 a 100 120 &RC 8 (DEGREES) 6000 5000 4000 3000 2S00 2000 1S00 1 0 0 0 2. SPIT-CREST RT L .S .C F I G U R E 4 1 b 4 0 60 80 100 120 ARC 9 (DEGREES) 140 160 180 , 3000 2500 2000 g ISOO I— o U-l > o ac 1 0 0 0 l N.W. CORNER F I G U R E 4 1 c 40 BO 80 ARC 6 (DEGREES) F i g u r e s 4 2 a , b , c . R e g r e s s i o n l i n e p l o t s o f t h r e e l o g -s p i r a l c u r v e s t e s t e d i n t h e s o u t h e a s t ha I f o f Wreck Bay . - I n f o r m a t i o n i n d i c a t e d i s t h e same as F i gu r e s 4 I a , b , c . S B HALF OF WRECK BAY 190 60DfJ 5000 4000 3000 2500 200O 1500 1000 — 1 1 r 4. S.E. POCKET BEACH 5001 F I G U R E 4 2 a MO ARC 9 (DEGREES) 6000 5000 4000 ~ 3 0 O 0 1— U J 2 5 0 0 u . \—» .a. 2000 £> 1500 UJ > v> 10001 r> 1—• Q cc ot. soo & S . E . C O R N E R (D F I G U R E 4 2 b 200 220 6. S 7300 E. CORNER (2) 7000 6300, 240 260 230 ARC B (DEGREES) I I I 3 0 0 Log r--0.001070 9 - 3.801 J. 200 240 260 ARC 0 (DEGREES) 320 F I G U R E 4 2 c 191 XI. BEACH STRUCTURES A. INTRODUCTION A number o f d i f f e r e n t beach forms e x i s t on the beach at Wreck Bay. They can be n a t u r a l l y grouped a c c o r d i n g to s i z e , i n t o major and minor s t r u c t u r e s . The major s t r u c t u r e s a re semi -permanent in that they s u r v i v e f o r a p e r i o d o f a year o r l onger , and are o f importance in many e n g i n e e r i n g problems concerned wi th c o a s t a l s t a b i l i t y . The minor s t r u c t u r e s a r e c u r s o r y , u s u -a l l y be ing de s t royed a f t e r a few hour s ; however when they do become p r e s e r v e d i n the g e o l o g i c a l co lumn,they p r o v i d e v a l u a b l e i n f o r m a t i o n on the pa Ieo-env ironment. Some o f the s t r u c t u r e s l i s t e d below have been d i s -cussed in d e t a i l in o t h e r c h a p t e r s . They a re s imply mentioned here f o r comp le tenes s , and r e f e r e n c e to the p e r t i n e n t c h a p t e r s w i l l be made when a p p r o p r i a t e . B. MAJOR STRUCTUKES 1. BERMS In p l a c e s no berm e x i s t s at a l l , e . g . beh ind P r o f i l e F; whereas e l sewhere , up to f ou r berms c h a r a c t e r i z e the back-s h o r e , e . g . between P r o f i I e C and the s p i t b a r (see chap te r on TRANSVERSE PROFILES, and Map I). 2. BARS A we l l d e f i n e d bar extended from the f o r e s h o r e between P r o f i les C and D southeastwards towards Sand Po in t dur -ing the summer o f 1968 ( P l a t e 16). I t s c r e s t was exposed at low 192. t i d e , and was s e p a r a t e d from t h e f o r e s h o r e by a 2 f o o t deep t r o u g h . A l e s s w e l l d e f i n e d bar extended i n t h e o p p o s i t e d i r e c -t i o n , from the f o r e s h o r e between P r o f i Ies E and F n o r t h w e s t -wards towards Sand P o i n t . T h i s bar was never exposed, and i t s p r e s e n c e was deduced l a r g e l y from t h e o b s e r v a t i o n t h a t waves broke i n t h i s r e g i o n , and then reformed c l o s e r to shore (see c h a p t e r on TRANSVERSE PROFILES, and Map I ) . 3. SPITBAR A body o f sand and g r a v e l has d i v e r t e d t h e mouth o f L o s t Shoe Creek f o r about 1250 f e e t northwestwards. I t does not f i t t he d e f i n i t i o n o f a s p i t p r e c i s e l y , s i n c e the l a t t e r s h o u l d t e r m i n a t e i n deep water. The term " s p i t b a r " has t h e r e f o r e been used t o d e s c r i b e i t (see c h a p t e r s on SEDIMENT SIZE ANALYSES, PLANIMETRIC SHAPE, and ECONOMIC GEOLOGY; a l s o Map I ) . 4. SYMMETRICAL CUSPATE FORELANDS Sand P o i n t , l o c a t e d i n the m i d d l e o f the beach, i s a good example o f a s y m m e t r i c a l c u s p a t e f o r e l a n d , and has formed i n response to wave d i f f r a c t i o n around Seal Rock. S w e l l e n t e r i n g the bay between Q u i s i t i s P o i n t and F l o r e n c i a I s l a n d i s s p l i t by S e a l Rock, and a p a t t e r n o f i n t e r s e c t i n g d i f f r a c t e d waves extends from i t s l e e back t o Sand P o i n t ( F r o n t i s p i e c e and F i g u r e 2 ) . These d i f f r a c t e d waves g e n e r a t e l i t t o r a l c u r r e n t s o v e r a r e l a t i v e l y s h o r t beach s e c t i o n , which converge i n the v i c i n i t y o f Sand P o i n t (see c h a p t e r s on SEDIMENT SIZE ANALYSES, and SAND MOVEMENT BASED ON TRACER DISPERSION; a l s o Map l)„ 193. An i n c i p i e n t c u s p a t e f o r e l a n d e x i s t s a p p r o x i m a t e l y £ m i l e s o u t h e a s t o f Sand P o i n t . I t owes i t s o r i g i n t o a s i m i -l a r b u t l e s s i n t e n s e wave p a t t e r n . S w e l l a p p r o a c h i n g t h e bay i s s p l i t by F l o r e n c i a I s l a n d , one p a r t d i f f r a c t i n g i n b e t w e e n S e a l Rock and t h e i s l a n d , and t h e o t h e r p a r t be tween Wya P o i n t and t h e i s l a n d . T h i s p a t t e r n o f i n t e r s e c t i n g d i f f r a c t e d waves e x t e n d s b a c k t o an a r e a on t h e b e a c h l o c a t e d a b o u t 500 f e e t s o u t h e a s t o f P r o f i l e E ( s e e F r o n t i s p i e c e and F i g u r e 2 ) . L i t t o -r a l d r i f t a t t h i s p r o f i l e was f o u n d t o be i n a n o r t h w e s t e r l y d i r e c t i o n , t h u s i n d i c a t i n g t h a t a v e r y s h o r t b e a c h s e c t i o n i s i n v o l v e d i n n o u r i s h i n g t h e i n c i p i e n t c u s p ( s e e c h a p t e r s on SAND MOVEMENT BASED ON WAVE PARAMETERS, and PLANI METRl C SHAPE; a I so Map I ) . C. MINOR STRUCTURES I. BEACH CUSPS D u r i n g t h e summer o f 1968 r e l i c t c o b b l e c u s p s e x i s -t e d on t h e b a c k s h o r e b e h i n d P r o f i l e C , and a l o n g t h e s e a w a r d edge o f t h e s p i t b a r . T h e s e f o rms s u r v i v e d t h r o u g h o u t t h e summer, bu t l o s t t h e i r c l a s s i c a l s h a p e w i t h t i m e ( F i g u r e 3 5 ) . A s e r i e s o f s e v e n p h o t o g r a p h s o f t h e r e l i c t c o b b l e c u s p b e h i n d P r o f i l e C were t a k e n at two day i n t e r v a l s , f r o m one neap t i d e p e r i o d t h r o u g h t i l l t h e n e x t . C o n t r a r y t o e x p e c t a -t i o n s , neap t i d e s 'were f o u n d t o be r e s p o n s i b l e f o r t h e p a r t i a l d e s t r u c t i o n o f t h e c u s p f o r m , by d i s l o d g i n g c o b b l e s and r o l l i n g them down t h e f o r & s h o r e . S p r i n g t i d e s on t h e o t h e r h a n d , p a c k e d 194. t h e c o b b l e s i n t o a n e a t p i l e , b u t i n so d o i n g , t h e h o r n o f t h e c u s p became r o u n d e d . T h r e e p h o t o g r a p h s o f t h e s e r i e s a r e shown i n P l a t e s 17a, b and c . C u s p s o f f i n e s and d e v e l o p e d p e r i o d i c a l l y a l o n g t h e f o r e s h o r e d u r i n g t h e summer a t l o c a t i o n s where l i t t o r a l c u r -r e n t s were w e a k e s t , f r o m P r o f i l e B t o P r o f i l e C , and f r o m P r o -f i l e E t o P r o f i l e F ( F r o n t i s p i e c e and P l a t e 1 8 b ) . T h e i r e x i s t -e n c e c o r r e l a t e d v e r y w e l l w i t h t i d a l r a n g e , b e i n g b e s t d e v e l o p -ed d u r i n g neap t i d e s , and a b s e n t d u r i n g s p r i n g t i d e s , A p o s i -t i v e c o r r e l a t i o n a p p e a r e d t o e x i s t b e t w e e n t h e c u s p a m p l i t u d e s , and t h e wave h e i g h t s a f f e c t i n g t h e d i f f e r e n t a r e a s ( s e e c h a p -t e r on SAND MOVEMENT BASED ON TRACER D ISPERSION; a l s o Map I ) . 2„ BEACH R IPPLES ( a ) . Backwash R i p p l e s T h e s e f e a t u r e s commonly o c c u r r e d on sandy f o r e s h o r e s b u t b e l o w t h e v a t e r t a b l e , t h e y were s l o w l y d e s t r o y e d by s a n d c r e e p and r i l l s . I n d i v i d u a l r i p p l e s were v e r y u n i f o r m and l o n g , u s u a l l y i n e x c e s s o f 50 f e e t ; t h e y had low a m p l i t i d e s o f a b o u t 0.1 f e e t , and w a v e l e n g t h s o f a p p r o x i m a t e l y 2 f e e t ( P l a t e s 18a and 1 9 a ) . In c r o s s - s e c t i o n t h e y a p p e a r e d t o be s l i g h t l y a s y m m e t r i c a l , w i t h t h e s e a w a r d s i d e s b e i n g f l a t t e r t h a n t h e l a n d w a r d s i d e s . They f o r m e d i n t h e t u r b u l e n t z o n e o f t h e b a c k -w a s h , and t h e r i p p l e f o rms w o u l d r e m a i n m o t i o n l e s s o r move s l o w l y s e a w a r d , b u t n e v e r o p p o s i t e t o t h e d i r e c t i o n o f backwash movement . T h e s e b e d f o r m s w o u l d a c t u a l l y be c l a s s i f i e d as dunes 195. by Simons et a l (1965), and b e l o n g t o t h e i r " l o w e r f l o w regime". They appeared t o form b e s t d u r i n g s p r i n g t i d e s ( P l a -t e s 17a, b, and c ) , and were commonly seen i n t h e embayments o f sandy cusps ( P l a t e I8b)„ (b) C u r r e n t R i p p l e s These o c c u r r e d i n s e v e r a l p l a c e s on t h e f o r e s h o r e where u n i d i r e c t i o n a l c u r r e n t s e x i s t e d , e.g. i n s h a l l o w c h a n n e l s b e h i n d beach r i d g e s where r i p p l e s i n d i c a t e d water movement p a r a l l e l t o the s h o r e ( o c c a s i o n a l l y p r e s e n t i n a r e a s between P r o f i l e s C and D, and E and F ) ; In r i p - c u r r e n t c h a n n e l s , where r i p p l e s i n d i c a t e d water movement towards the sea ( p r e s e n t throughout t h e summer between P r o f i l e s A and B ) ; and where the lower f o r e s h o r e was a f f e c t e d by v e r y s m a l l waves and a weak, u n i f o r m l i t t o r a l c u r r e n t e x i s t e d ( a t P r o f i l e A ) . I n d i v i d u a l r i p p l e s were c u r v e d i n shape, and s h o r t and i r r e g u l a r i n l e n g t h , a v e r a g i n g 0,5 f e e t ; they had low a m p l i t u d e s o f about 0.1 f e e t , and s h o r t wave l e n g t h s a p p r o x i -m a t e l y 0.4 f e e t ( P l a t e I8c)„ In c r o s s - s e c t i o n they were s t r o n g l y a s y m m e t r i c a l , w i t h the s i d e from which the c u r r e n t came b e i n g convex, and the leeward s i d e b e i n g s h o r t and s t e e p . These bedforms a l s o b e l o n g t o the " l o w e r f l o w regime" o f Simons et a l ( 1 9 6 5 ) , and would be c l a s s i f i e d as t r u e r i p p l e s . They formed as a r e s u l t o f a weaker c u r r e n t v e l o c i t y than t h a t which produced t h e backwash r i p p l e s . 196. 3. RHOMBOID PATTEKNS C o n s i d e r a b l e c o n f u s i o n e x i s t s i n t h e 1 1 t e r a t u r e r e -g a r d i n g t h e s e f e a t u r e s . F o r e x a m p l e , Emery (I960) and Hoyt and Henry (1963) r e f e r t o them as " r h o m b o i d r i p p l e m a r k s " , w h e r e a s Bascom (1964) c a l l s them " b a c k w a s h d i a m o n d s " . Emery (I960) s t a t e s t h a t t h e y f o rm o n l y on t h e l ower s a t u r a t e d p a r t s o f b e a c h e s , a t s l o p e a n g l e s b e t w e e n 2 ° and 1 0 ° . Hoyt and Henry (1963) on t h e o t h e r h a n d , f o u n d a t S a p e l o I s l a n d , G e o r g i a , t h a t t h e y f o rmed rn equal mirnber* i n t h e u p p e r and l ower f o r e s h o r e , a t s l o p e a n g l e s b e t w e e n 0,5° and 2 ° . B o t h Hoyt and Henry (1963) and Bascom (1964) d e s c r i b e t h e d i m e n s i o n s o f t h e rhombs , and r e f e r t o t h e i r " d e p t h " as b e i n g b e t w e e n 1/16 and 1/4 i n c h -h e n c e p r o b a b l y t h e i r d e s c r i p t i o n as " r i p p l e m a r k s " . The w r i t e r c o n s i d e r s t h i s d e p t h d i m e n s i o n i n s i g n i f i c a n t i n c o m p a r i -son t o t h e o t h e r rhomb d i m e n s i o n s , and t h e r e f o r e t h e t e r m " r h o m b o i d p a t t e r n " i s b e l i e v e d t o be more a p p r o p r i a t e . T h r e e d i s t i n c t t y p e s o f r h o m b o i d p a t t e r n were o b -s e r v e d a t Wreck B a y : The most common t y p e o c c u r r e d on t h e s l i g h t l y f l a t s e a w a r d s i d e o f backwash r i p p l e s ( P l a t e 1 9 a ) . B e a c h s l o p e s v a r i e d f r o m 0 . 8 ° t o 1.4°, and a l t h o u g h i t f o r m e d on b o t h u p p e r and l ower f o r e s h o r e s , i t r a p i d l y d i s i n t e g r a t e d b e l o w t h e w a t e r t a b l e due t o s and c r e e p and r i l l s . The rhomb a p i c e s m e a s u r e d a b o u t 45°, s h o r e w a r d p o i n t i n g o n e s c o n s i s t i n g o f l i g h t c o l o u r e d sand g r a i n s and s h e l l - h a s h , and seaward 197. p o i n t i n g o n e s o f d a r k c o l o u r e d h e a v y m i n e r a l s . I t a p p e a r e d t o f o rm s u d d e n l y as t h e l a s t t h i n f i l m o f backwash r e c e d e d f r o m t h e r i p p l e s . D e v e l o p e d o n l y i n t h e s o u t h e a s t p o r t i o n o f t h e bay b e t w e e n P r o f i l e s F and G, was a r h o m b o i d p a t t e r n q u i t e d i f f e r e n t i n d i m e n s i o n s and mode o f f o r m a t i o n t o t h e t y p e d e s c r i b e d a b o v e . I t d e v e l o p e d on a smooth u n r i p p l e d s a n d s u r f a c e w i t h b e a c h s l o p e o f 0 . 8 ° t o 1 . 0 ° . Two r e q u i r e m e n t s were a p p a r e n t l y e s s e n t i a l f o r i t s f o r m a t i o n ; a h i g h p r o p o r t i o n o f h e a v y m i n e r a l and s h e l l - h a s h c o m p o n e n t s i n t h e b e a c h s a n d , a n d a s u c c e s s i o n o f t h i n s h e e t s o f f r e s h w a t e r w a s h i n g o v e r t h e b e a c h s u r f a c e . Amp le f r e s h w a t e r emerges f r o m t h e c l i f f b a s e as s p r i n g s i n t h i s v i c i n i t y , b u t where i t washes down t h e b e a c h f a c e as an u n d i s t u r b e d g l a s s y s h e e t t h e p a t t e r n d o e s no t f o r m . Rhomb a p i c e s m e a s u r e d a p p r o x i m a t e l y 3 0 ° and t h e i r c o m p o s i t i o n s were e x a c t l y o p p o s i t e t o t h o s e d e s c r i b e d a b o v e v i z . s h o r e w a r d p o i n t i n g o n e s c o n s i s t e d o f d a r k c o l o u r -ed h e a v y m i n e r a l s , and s e a w a r d p o i n t i n g o n e s o f f i n e s h e l l -h a s h ( P l a t e 19b ) . The fo rms were r e l a t i v e l y u n s t a b l e , and s l o w l y m u t a t e d w i t h t i m e . The t h i r d t y p e was s i m i l a r t o o t h e r r h o m b o i d p a t t e r n s e x c e p t t h a t i t p o s s e s s e d no s e a w a r d p o i n t i n g a p i c e s , and a c t u a l l y r e s e m b l e d g l a c i a l c r a g - a n d - t a i I s t r u c t u r e s i n m i n i a t u r e ( P l a t e 1 9 c ) . I t was a common f e a t u r e on u n r i p p l e d s andy b e a c h e s c o n t a i n i n g s m a l l i s o l a t e d p e b b l e s , and was p a r t i c u -198. l a r l y n o t i c e a b l e i n a r e a s c o n t a i n i n g a b u n d a n t f i n e s h e l l -h a s h . The a p i c e s o f t h e f o r m s , w h i c h p o i n t e d l a n d w a r d s , m e a s u r e d a p p r o x i m a t e l y 7 0 ° , and were composed o f d a r k c o l o u r e d h e a v y m i n e r a l s t h u s r e s e m b l i n g t h e s e c o n d p a t t e r n d e s c r i b e d a b o v e . A l l a p i c a l p o i n t s were marked by s m a l l p e b b l e s , w h i c h i n e v e r y c a s e , were o r i e n t e d w i t h t h e i r l o n g e s t a x e s p a r a l l e l t o t h e b e a c h . They a p p e a r e d t o f o rm as t h e l a s t t h i n f i l m o f backwash r e t r e a t e d down t h e f o r e -s h o r e . As soon as a p e b b l e r o l l e d t o a s t o p , s h e l l - h a s h and l i g h t c o l o u r e d sand w o u l d m o m e n t a r i l y c o n t i n u e t o be t r a n s p o r t e d a r o u n d i t s e d g e s , u n t i l i t f i n a l l y s e t t l e d i n t o t h i s p s e u d o - r h o m b o i d p a t t e r n as t h e l a s t w a t e r d i s s i p a t e d . Above t h e w a t e r t a b l e t h e s e f o rms r e m a i n e d u n t i l t h e n e x t f l o o d t i d e , b u t b e l o w t h e w a t e r t a b l e , t h e y were r a p i d l y d e s t r o y e d by s and c r e e p . k.RILL MARKS T h e s e f o rms d e v e l o p e d on sandy f o r e s h o r e a r e a s , b e l o w t h e w a t e r t a b l e , and some t i m e a f t e r t h e t i d e had r e c e d e d . Two g e n e r a l t y p e s were r e c o g n i z e d , d e p e n d i n g on t h e c o n d i t i o n o f t h e f o r e s h o r e . Where t h e f o r e s h o r e was smooth and u n r i p p l e d , t h e y w o u l d commence " g r o w t h " w e l l b e l o w t h e w a t e r t a b l e as a s e r i e s o f t i n y i r r e g u l a r c h a n n e l s . T h e s e c h a n n e l s w o u l d e x t e n d t h e m s e l v e s up t h e b e a c h , u n t i l a number o f them u n i t e d i n t o a s i n g l e l a r g e c h a n n e l , w h i c h t e r m i n a t e d g r o w t h c l o s e t o t h e w a t e r t a b l e l i n e o f e m e r g e n c e . The d e n d r i t i c f o r m w h i c h 199. d e v e l o p e d r e s e m b l e d t h e l ower p a r t o f a r i v e r s y s t e m , where t h e r i v e r c h a n n e l o p e n s up i n t o a d e l t a t o w a r d s t h e s e a . • The o t h e r t y p e o f r i l l mark o c c u r r e d where t h e f o r e s h o r e p o s s e s s e d backwash r i p p l e s ( P l a t e 18a ) . H e r e , a s i m i l a r s e q u e n c e o f e v e n t s w o u l d commence on t h e s e a w a r d s i d e o f t h e r i p p l e s , bu t o n c e t h e r i l l had c r o s s e d a r i p p l e c r e s t , s u r p l u s w a t e r t r a p p e d i n t h e i n t e r - r i p p l e t r o u g h w o u l d be d r a i n e d , and a d e n d r i t i c p a t t e r n t o w a r d s t h e l a n d w o u l d d e v e l o p . A l t h o u g h t h i s f o r m was s h o r t e r t h a n t h e t y p e d e s c r i b e d a b o v e , i t r e s e m b l e d an e n t i r e r i v e r s y s t e m f r o m t h e s o u r c e t o t h e d e l t a . O c c a s i o n a l l y , r i l l " c a p t u r e " r e s u l t e d i n d o u b l i n g o f t h e r i l l l e n g t h , and w a t e r w o u l d be c h a n n e l e d a c r o s s t h e u p p e r d e l t a by s m a l l l e v e e s . The manner o f g r o w t h o f t h e s e f e a t u r e s i s r a t h e r c o m p l e x . G r o u n d w a t e r e s c a p i n g f r o m t h e b e a c h i s a p p a r e n t l y d i r e c t e d t o w a r d s t h e c h a n n e l s b e c a u s e o f t h e i r s l i g h t l y l ower e l e v a t i o n . The g r o w t h p o i n t o f a r i l l seems t o e x t e n d up t h e b e a c h f a c e as v e r y f i n e s and g e t s s l u m p e d i n t o t h e c h a n n e l h e a d ; t h e s a n d t h e n moves s l o w l y down t h e c h a n n e l i n a s e m i -s u s p e n d e d s t a t e l i k e a s l u r r y . 5. SWASH MARKS T h e s e f o r m e d r e g u l a r l y on s andy f o r e s h o r e a r e a s , and c o n s i s t e d o f a r c u a t e l i n e s o f s h e l l - h a s h , l i g h t c o l o u r e d s a n d and d e b r i s . Above t h e w a t e r t a b l e t h e i r o u t l i n e s l a s t e d f o r a few h o u r s , w h e r e a s b e l o w i t , t h e y were r a p i d l y d e s -t r o y e d by s and c r e e p 0 200. 6. SAND DOMES T h e s e o c c u r r e d o n t h e s andy f o r e s h o r e , a b o v e t h e w a t e r t a b l e , and c l o s e t o t h e swash l i m i t . They d e v e l o p when w a t e r f r o m t h e f i r s t swash s i n k s i n t o d r y b e a c h s a n d , and i n -t e r g r a n u l a r a i r becomes c o m p r e s s e d i n t h e more p o r o u s s a n d l a y e r s , t h u s f o r c i n g t h e o v e r i y i n g wet m a t e r i a l up I i k e a l a c c o l i t h . The s e c o n d swash u s u a l l y r e s u l t s i n t h e i r d e c a p i t a -t i o n , l e a v i n g a r i n g o f d a r k c o l o u r e d h e a v y m i n e r a l s a r o u n d t h e p o i n t o f a i r e s c a p e , 7. ORGANISM MARKINGS T h e s e were no t t o o common a t Wreck B a y , e x c e p t i n t h e l e e o f C u i s ' t i s and Wya P o i n t s ( s e e c h a p t e r o n MARINE L I F E ) . 201 P l a t e 16. V i e w l o o k i n g n o r t h w e s t f r o m Sand P o i n t a t low t i d e , waves c a n be s e e n b r e a k i n g on t h e l o n g s h o r e b a r i n f r o n t o f P r o f i Ie D. P l a t e !7a. V i e w o f a r e l i c t c o b b l e c u s p on t h e u p p e r f o r e s h o r e a t P r o f i l e C d u r i n g a p e r i o d o f neap t i d e s (22 J u l y 1968),, The p h o t o g r a p h was t a k e n f r o m r o d C3 ; C i i s e v i d e n t on tcp o f the c u s p , and C2 on t h e s andy f o r e s h o r e \r. f r o n t o f t h e c u s p . P l a t e 17b, As P l a t e 17a d u r i n g t h e s u c c e e d i n g h i g h t i d e p e r i o d (26th J u l y 1968). P l a t e 1 7 c As P l a t e 17a d u r i n g t h e s u c c e e d i n g neap t i d e p e r i o d (30th J u l y 1968), 202 P l a t e I8a„ R i l l s a c t i v e l y e r o d i n g backwash r i p p l e s i n t h e v i c i n i t y o f P r o f i l e C. Note r i l l " c a p t u r e " by some o f them a c r o s s two a d j a c e n t r i p p l e s . P l a t e I8b„ Sandy beach cu sps w i t h backwash r i p p l e s i n t h e embayments. V iew f rom the c l i f f edge between P r o f i Ie B and t he mouth o f L o s t Shoe C reek . (Compare t h i s pho tog raph w i t h P l a t e 23a, wh ich i s t he same v i e w t aken i n w i n t e r . P l a t e 1 8 c C u r r e n t r i p p l e s on t h e lower f o r e s h o r e a t P r o f i l e A, i n d i c a t i n g c u r r e n t movement towards t h e land ( r i g h t - h a n d s i d e o f p h o t o g r a p h ) . Rod A7 i s seen i n the f o r e g r o u n d , and Q u i s i t i s P o i n t i n the backg round. P l a t e 19a. Rhomboid p a t t e r n d e v e l o p e d on t h e s e a w a r d s i d e o f backwash r i p p l e s . Landward p o i n t i n g a p i c e s c o n s i s t o f l i g h t c o l o u r e d m i n e r a l s and s h e l l -hash,, The p h o t o g r a p h was t a k e n n e a r P r o f i Ie F. P l a t e 19b. Rhomboid p a t t e r n d e v e l o p e d on a g e n t l y s l o p i n g , u n r i p p l e d f o r e s h o r e b e t w e e n P r o f i l e s F and G. L a n d w a r d p o i n t i n g a p i c e s a r e o f d a r k c o l o u r e d h e a v y m i n e r a l s . P l a t e 1 9 c P s e u d o - r h o m b o i d p a t t e r n d e v e l o p e d i n t h e l e e o f s m a l l p e b M e s , L a n d w a r d p o i n t i n g a p i c e s a r e o f d a r k c o l o u r e d h e a v y m i n e r a l s . The p h o t o g r a p h was t a k e n b e t w e e n P r o f i l e s F and G„ 205. D, MINOR WAVE TYPES ASSOCIATED WITH BEACH STRUCTURES 1. REFLECTED WAVES AND WATER SPOUTS In t h e v i c i n i t y o f P r o f i l e D, a s t e e p g r a v e l s t e p e x i s t e d a t t h e b a s e o f t h e f o r e s h o r e i n e a r l y summer; Seaward f r o m t h e r e , a s h a l l o w c h a n n e l a p p r o x i m a t e l y 100 f e e t w ide arid 2 f e e t d e e p , i s o l a t e d t h e l o n g s h o r e b a r d e s c r i b e d e a r l i e r f rom t h e b e a c h ( s e e Map I ) . W i t h t h e s t a r t o f f l o o d t i d e , s m a l l s p i l l i n g waves w o u l d wash ov - r t h e b a r , c r o s s t h e c h a n -n e l , and i m p i n g e a g a i n s t t h e g r a v e l s t e p ( P l a t e 2 0 a ) . P a r t o f t h e waves e n e r g y was d i s s i p a t e d as swash w h i c h p e r m e a t e d r a p i d l y i n t o t h e g r a v e l , and t h e r e m a i n i n g e n e r g y was r e f l e c t -ed as an o n d u l a r b o r e (P . L e B l o n d , 1970 , p e r s o n a l commun i -c a t i o n ) , o r r e f l e c t e d wave ( P l a t e 2 0 b ) . T h i s e v e n t h e l p e d t o m a i n t a i n t h e c o n f i g u r a t i o n o f t h e g r a v e l s t e p . The r e f l e c t e d wave t h e n t r a v e l l e d b a c k a c r o s s t h e c h a n n e l , and c o l l i d e d w i t h t h e n e x t i n c o m i n g s p i l l i n g wave o v e r t h e c r e s t o f t h e l o n g s h o r e b a r . U s u a l l y t h e s e two waves a p p r o a c h e d e a c h o t h e r a t an a n g l e r e s u l t i n g i n a " w a t e r s p o u t " , w h i c h t r a v e r s e d r a p i d l y a l o n g t h e b a r c r e s t ( P l a t e 2 0 c ) . T h i s e v e n t h e l p e d t o m a i n t a i n t h e l o n g s h o r e b a r , by p r e v e n t i n g f i n e s and f r om b e i n g swept i n t o t h e c h a n n e l w i t h e a c h i n c o m i n g s p i l l i n g wave. 2. HYDRAULIC JUMP WAVES T h e s e waves were named by G r a n t ( 1 9 4 8 ) , b u t a r e a l s o known as o n d u l a r b o r e s by p h y s i c a l o c e a n o g r a p h e r s (P . L e B l o n d , 1970, p e r s o n a l c o m m u n i c a t i o n ) . They commonly o c c u r r e d a l o n g 206. s andy b e a c h s e c t i o n s where i n c i d e n t waves were h i g h . T h e i r f o r m a t i o n d e p e n d e d on t h e r e l a t i v e v r l o c i t i e s o f t h e backwash and i n c i d e n t waves . I f t h e i n c i d e n t t r a n s l a t o r y waves v e l o c i -t y e x c e e d e d t h a t o f " h e b a c k w a s h , i t w o u l d b r e a k and s p i l l o v e r t h e backwash f o r a s h o r t d i s t a n c e up t h e f o r e s h o r e . On t h e o t h e r h a n d , i f t h e backwash v e l o c i t y e x c e e d e d t h a t o f the n e x t i n c o m i n g t r a n s l a t o r y wave , t h e t u r b u l e n t backwash h e a v i l y c h a r g e d w i t h s u s p e n d e d s a n d , w o u l d o v e r - r i d e t h e c l e a r w a t e r o f t h e i n c i d e n t wave. In t h i s c a s e h y d r a u l i c jump waves o r o n d u l a r b o r e s w o u l d f o r m , and rema in e s s e n t i a l l y s t a t i o n a r y as t h e two w a t e r mas ses moved r a p i d l y i n o p p o s i t e d i r e c t i o n s , one on top o f t h e o t h e r ( P l a t e 2 1 a ) . On o c c a s i o n s , when i n c i -d e n t wave and backwa?'n v e l o c i t i e s were b o t h v e r y h i g h , a h y d r a u l i c jump wave w o u l d m o m e n t a r i l y r i s e up t o a b o u t 2 f e e t , and t h e n c o l l a p s e . The e f f e c t o f t h i s e v e n t on t h e f o r e s h o r e was t o t r a n s p o r t m a t e r i a l s c o u r e d by t h e b a c k w a s h , p a s t t h e s h o a l i n g z o n e , and t h u s t e m p o r a r i l y remove i t f r om t h e b e a c h env i r onment . 3. SANU WAVES The s o u t h e a s t c o r n e r o f t h e b e a c h be tween P r o f U e s F and G was u n i c u e , i n t h a t a number o f p e r e n n i a l f r e s h w a t e r s p r i n g s emerged f rom t h e c l i f f b a s e . T h e s e s p r i n g s c o a l e s c e d on t h e b a c k s h o r e i n t o s m a l l c r e e k s , w h i c h c u t t h r o u g h t h e summer berm and l e f t i t as a s e r i e s o f d i s c r e t e s andy mounds (Map I ) . On t h e 30th J u l y 1968, 32 o f t h e s e c r e e k s were f o u n d 207 . c u t t i n g t h r o u g h t h e summer b e r m , and i n so d o i n g , b e h a v e d as n a t u r a l f l u m e c h a n n e l s r e s p o n s i b l e f o r t h e f o r m a t i o n o f s and w a v e s l ower down on t h e f o r e s h o r e . The s and waves were s p a c e d f a i r l y r e g u l a r l y a t a b o u t ! „ 5 f e e t a p a r t , and a f t e r a few s e c o n d s , w o u l d d i s i n t e -g r a t e due t o some f l o w r a t e d i s t u r b a n c e h i g h e r up i n t h e f l u m e . T h i s f o r m a t i o n - d i s i n t e g r a t i o n p r o c e s s had a p e r i o d i c i t y o f a b o u t 6 p e r m i n u t e . A c c o r d i n g t o Inman ( i n : S h e p a r d , 1 9 6 3 ) , t h e f l o w r a t e c h a n g e d f r o m h i g h ( s h e e t f l o w ) t o v e r y h i g h ( s a n d w a v e s ) , and Bascom (1964) s t a t e s t h a t when t h e f l o w r a t e i s b e t w e e n 2,2 and 2,5 f e e t p e r s e c o n d , t h e f o r m s m i g r a t e a g a i n s t t h e c u r r e n t . They w o u l d t h e r e f o r e b e l o n g t o t h e " u p p e r f l o w r e g i m e " o f S imons e t a l ( 1 9 6 5 ) , and c o r r e s p o n d t o t h e " a n t i - d u n e s " o f G i l b e r t ( 1 9 1 4 ) . M i g r a t i o n r a t e o f t h e s and waves up t h e f o r e s h o r e was a p p r o x i m a t e l y 2 f e e t p e r m i n u t e , and was a c h i e v e d by s h e e t f l o w o f s and p a r t i c l e s f r o m t h e l e e o f o n e s and wave , t o t h e f r o n t o f t h e n e x t o n e . J u s t p r i o r t o d i s i n t e g r a t i o n o f t h e s and w a v e s , t h e y c h a r a c t e r i s t i c a l l y a s sumed t h e s h a p e o f a b u l l ' s h o r n s ( P l a t e 2 1 b ) . The waves t h e m s e l v e s had l i t t l e r e l e v a n c e t o b e a c h s t r u c t u r e s , b u t as m e n t i o n e d e a r l i e r , t h e f r e s h w a t e r c r e e k s were r e s p o n s i b l e f o r c o n s i d e r a b l e e r o s i o n o f t h e summer berm and u p p e r f o r e s h o r e . P l a t e 2 0 a . A s m a l l s p i l l i n g wave a p p r o a c h e s t h e g r a v e l s t e p n e a r P r o f i l e D„ The p h o t o g r a p h was t a k e n a t t h e s t a r t o f f l o o d t i d e . P l a t e 20b. A few s e c o n d s a f t e r P l a t e 2 0 a . A s h o r t swash t r a v e r s e d up t h e g r a v e l f o r e s h o r e , and a r e f l e c t e d wave t r a v e l l e d b a c k a c r o s s t h e t r o u g h t o w a r d s t h e l o n g s h o r e b a r . P l a t e 2 0 c . A few s e c o n d s a f t e r P l a t e 20b. The r e f l e c t e d wave ( l e f t - h a n d s i d e o f p h o t o g r a p h ) c o l l i d e d w i t h t h e n e x t i n c o m i n g s p i l l i n g wave ( r i g h t - h a n d s i d e o f p h o t o g r a p h ) , A w a t e r s p o u t f o r m e d w h i c h t r a v e l l e d a l o n g t h e c r e s t o f t h e l o n g s h o r e be , No te waves b r e a k i n g i n t h e d i s t a n c e on Sand P o i n t . PI a t e 2 1 a . H y d r a u l i c jump waves o r o n d u l a r b o r e s , d e v e l o p e d by t u r b u l e n t backwash o v e r - r i d i n g t h e i n c o m i n g s p i l l i n g wave. The p h o t o g r a p h was t a k e n a t Sand Po i n t » PI a t e 21b . Sand waves w i t h c h a r a c t e r i s t i c " b u l l ' s h o r n " shape The p h o t o g r a p h was t a k e n be tween P r o f i l e F and G, j u s t s e a w a r d f r o m where a f r e s h - w a t e r c r e e k c u t t h r o u g h t h e summer b e r m . 209 210 X I I . EC0N0MIC GEOLOGY A. REGIONAL ASPECTS E c o n o m i c i n t e r e s t i n t h e r e g i o n a r o u n d Wreck Bay began i n 1898, a t a t i m e when l ode and p l a c e r p r o d u c t i o n o f g o l d was a t h i g h l e v e l i n B r i t i s h C o l u m b i a . P r o s p e c t o r s were s u c c e s s f u l i n l o c a t i n g f i n e p l a c e r g o l d on t h e b e a c h a t Wreck B a y , and a l o n g Kennedy R i v e r , a number o f s m a l l g o l d - b e a r i n g q u a r t z v e i n s were w o r k e d . V. Do lmage o f t h e G e o l o g i c a l S u r v e y o f C a n a d a b r i e f l y d e s c r i b e d t h e a r e a i n 1919 and 1920, and m e n t i o n e d t h a t : " T h i s p a r t o f t h e i s l a n d i s t h i n l y p o p u l a t e d , c h i e f l y by Indians o f a most p r i m i t i v e t y p e . " S i n c e t h i s t i m e , a number o f s m a l l c o m p a n i e s and p r o m o t i o n g r o u p s h a v e shown i n t e r e s t i n t h e b e a c h p l a c e r s , and e v e n t o d a y a few i n d i v i d u a l s d e r i v e some income f r o m w o r k i n g b e a c h c o n c e n t r a t e d u r i n g t h e w i n t e r ( P l a t e 23a). In t h e l a t e 1 9 5 0 ' s a t t e n t i o n was b r i e f l y d i r e c t e d t o w a r d s t h e " b l a c k s a n d s " m a g n e t i t e c o n t e n t a t Wreck Bay ( H o l l a n d and N a s m i t h , 1 9 5 8 ) , and i n 1961, B r y n n o r M i n e s commenced d e v e l o p m e n t o f a m a g n e t i t e o r e - b o d y on Draw C r e e k , w h i c h f l o w s e a s t i n t o B a r k l e y S o u n d . S i n c e p r o d u c t i o n began i n A p r i l 1962 u n t i l t h e end o f 1966, t h e m i n e p r o d u c e d 4 , 400 ,000 t o n s o f o r e ( E a s t w o o d , 1968 ) . S e v e r a l o t h e r s m a l l i r o n and c o p p e r s h o w i n g s i n t h e a r e a have b e e n known f o r a l ong t i m e , and o c c u r where g r a n o d i o r i t e o r d i o r i t e o f t h e Kennedy B a t h o l i t h h a v e i n t r u d e d Q u a t s i n o L i m e s t o n e s . 211. B . SUMMARY OF G O L D P K O D U C T I O N AND SAMPLING AT W R E C K BAY The t o t a l amount o f g o l d e x t r a c t e d f r o m t h e b l a c k s and s Is unknown, bu t f r o m r e c o r d s t h a t were k e p t In t h e p a s t , It Is a p p a r e n t t h a t r i c h pay s t r e a k s were l o c a t e d and m i n e d . From 1896 u n t i l 1901, $20,589 w o r t h o f g o l d was r e -c o v e r e d ($ 15 .20 / oz„ ) , and i n 1919, when Do lmage v i s i t e d t h e a r e a , two s a m p l e s c o l l e c t e d a t t h e c l i f f b a s e p r o d u c e d p h e n o -menal a s s a y s : ( i ) c o n c e n t r a t e s f r o m 3 pan s - $ 4 1 6 . 7 0 / c u . y d . , ( i i ) u n p a n n e d a v e r a g e b l a c k s and - $ I 1 5 .20 / c u , y d . ($20.67/oz). In 1920, t h e U c l u e l e t P l a c e r M i n i n g Company was f o r m e d , and du r i n g t h a t summer, $ 9 , 4 0 0 w o r t h o f g o l d was r e c o v e r e d f r o m 600 y a r d s o f g r a v e l ( $ l 5.75 / o z ) . From 1931 t o 1935, a t o t a l o f $ 1 , 9 9 7 was t a k e n ($21„60 /oz ) . In 1936, S t e v e n s o n c o n d u c t e d a s e m i q u a n t i t a t i v e i n v e s t i g a t i o n on t h e r e c o v e r a b i I i t y o f g o l d f r o m a number o f d i f f e r e n t e n v i r o n m e n t s , t h e r e s u l t s o f w h i c h a r e s u m m a r i s e d i n T a b l e X V I I I . Sample l o c a t i o n s N u mb e r o f samp 1es 0 z ' s / c u . y d . A v e r a g e 1 va l u e / ^ c u . y d . Range A v e r a g e B e a c h b l a c k s and s 5 0 , 0 4 8 - 3 .488 1.086 $38.01 G r a v e l f r om c l i f f f a c e 7 T r - 0 . 0 9 6 0 . 0 3 0 $1 .05 G r a v e ' f r o m b e h i n d c l i f f 4 T r - 0 . 0 0 9 0 . 0 0 2 $ 0 . 0 8 G r a v e l i n L o s t Shoe C r e e k I 0 . 0 2 4 0 . 0 2 4 $ 0 . 8 4 * ( $ 3 5 . 0 0 / o z ) Tab Ie XVI I I. Summary o f s e m i - q u a n t i t a t i v e I n v e s t i g a t i o n o f G o l d R e c o v e r a b i I i t y by S t e v e n s o n ( 1 9 3 6 ) . 212. A l l mining and sampl ing was conducted i n the v i c i n i t y o f Lost Shoe Creek„ On the s t r eng th o f t h i s , the present i n v e s t i g a t i o n was des igned to emphasise examinat ion o f t h i s p a r t i c u l a r beach s e c t i o n , C. PRESENT INVESTIGATION AND RESULTS In c o n j u n c t i o n with genera l f i e l d sampl ing o f the a rea (see APPENDIX), a number o f a d d i t i o n a l samples were panned to c o n c e n t r a t e go ld and magnet i te f o r l a t e r e v a l u a t i o n in the l a b o r a t o r y . Approx imate ly 10 lbs . o f m a t e r i a l was used in each c a s e , and t h i s was panned down to about I l b . In the l a b o r a t o r y , magnet i te was f i r s t e x t r a c t e d with a hand-magnet, and I t s p r o p o r t i o n by weight roughly e s t i m a t e d . The ba l ance o f the heavy minera l c o n c e n t r a t e was then p roces sed on a Super Panner, and the number o f " c o l o u r s " counted and i s o l a t e d * The r e s u l t s o f t h i s work are l i s t e d in Tab le XIX, It should be mentioned here that dur ing the summer Of 1968, f i v e p r o s p e c t - h o l e s were dug at v a r i o u s p l a c e s on the beach by an unnamed e x p l o r a t i o n company. A mechanica l shovel was u sed , and the ho les measured about 6 f ee t a c r o s s , and 6 f ee t deep. An attempt by the w r i t e r to sample the beach in depth with hand-auger and c a s i n g met with l i t t l e succes s ; c o n s e q u e n t l y , one o f the p ro spec t ho les was channel sampled in four 1,3 foot leng ths . Th i s p a r t i c u l a r ho le was l oca ted 850 f e e t northwest o f P r o f i l e D, and 90 f e e t from the c l i f f b a s e , 213, j u s t b e h i n d t h e w i n t e r berm c r e s t ( P l a t e 23b). P. ESTIMATED VALUE OF GOJLD NEAR LOST SHOE CREEX The d i a m e t e r o f g o l d c o l o u r s was a r b i t r a r i l y b r o k e n down i n t o t h r e e c a t a g o r i e s , as shown i n T a b l e X I X , t o s i m p l i f y d e t e r m i n a t i o n o f a mean p a r t i c l e s i z e . C o l o u r s were e x a m i n e d u n d e r a p e t r o g r a p h i c m i c r o s c o p e w i t h a m i c r o m e t e r e y e - p i e c e ( P l a t e 2 2 ) . R e s u l t s i n T a b l e X I X c o n f i r m t h a t t h e b a c k s h o r e n e a r L o s t Shoe C r e e k c o n t a i n s t h e h i g h e s t g o l d v a l u e s . We w i I I t h e r e f o r e c o n s i d e r s a m p l e s f r o m NWR-5a ( 1 , 3 7 5 f e e t n o r t h w e s t o f L o s t Shoe C r e e k ) t o S E R - 5 a ( 1 , 2 5 0 f e e t s o u t h e a s t o f L o s t Shoe C r e e k ) , f o r a t o t a l b e a c h s e c t i o n o f 2,625 f e e t (Map I ) . T h e s e 9 s a m p l e s t o g e t h e r c o n t a i n e d a t o t a l o f 72 g o l d c o l o u r s . A s s u m i n g t h e c a t e g o r y m i d p o i n t s t o b e : l a r g e = 3 0 Q u , medium = 150/x, and s m a l l = 50»a, m u l t i p l y i n g t h e s e v a l u e s by t h e number o f p a r t i c l e s i n e a c h c a t e g o r y , and d i v i d i n g t h e summed t o t a l by 72, we o b t a i n t h e mean d i a m e t e r o f t h e c o l o u r s , vI z . I I I. I/JL. H i t e ( q u o t e d i n B a t e m a n , 1965) has e s t i m a t e d t h a t 17 x 10 g o l d d i s c s h a v i n g an a r e a o f 0.1 s q . m m . , a v e r a g e d a b o u t I o z . t r o y f o r t h e Snake R i v e r , U . S . A . No s p e c i f i c a t i o n on d i s c t h i c k n e s s was made, so t h i s v a l u e i s a s sumed t o be c o n s t a n t r e g a r d l e s s o f s o u r c e . T h e s e d i s c s have a d i a m e t e r o f 1 1 . 2 8 ^ ( f r o m f i r 2 = lOOp.). T h e r e f o r e (17 x IO 6 x l l . 2 8 ) / l l l . l = 1 ,700,000 c o l o u r s ( a p p r o x i m a t e l y ) , w i t h d i a m e t e r I I I . w o u l d a v e r a g e I o z . t r o y . 214. Now e a c h o f t h e 9 s a m p l e s o r i g i n a l l y c o n s i s t e d o f a b o u t 10 l b s . o f m a t e r i a l . We c a n t h e r e f o r e say t h a t 72/1,700,000 o z ' s o f g o l d were r e c o v e r e d f r om 9/200 t o n s o f m a t e r i a l f r om t h e b a c k s h o r e . The amount o f g o l d c o n t a i n e d i n I t o n o f b a c k s h o r e m a t e r i a l i s g i v e n b y : 72 200 1,700,000 * — = 0.0009412 o z ' s . The v a l u e o f t h i s a t $35.00/oz = 3 .289c/ton o r 5 . 2 7 1 c / cu .yd . ( u s i n g t h e e q u i v a l e n t : J<j/ton = l . 6 c / c u . y d . , B a t e m a n , 1965). T h i s f i g u r e r e p r e s e n t s t h e t e n o r o f s u r f a c e m a t e r i a l d e r i v e d f r o m 2,625 f e e t o f b a c k s h o r e . The a v e r a g e w i d t h o f b a c k s h o r e i n t h i s r e g i o n i s 100 f e e t , and u s i n g t h e r e p o r t e d d e p t h o f 20 f e e t ( o r more ) t o t h e s u r f a c e o f t h e g r e y c l a y ( S t e v e n s o n , 1936), g i v e s d i m e n s i o n s f o r t h e z o n e i n y a r d s as f o l l o w s : l e n g t h 875, b r e a d t h 33, and d e p t h 7. T h e r e f o r e v o l u m e o f t h e z o n e = 202,100 c u . y d s . A s s u m i n g e x t e n s i o n o f t h e s u r -f a c e t e n o r w i t h d e p t h , we o b t a i n t h e a p p r o x i m a t e v a l u e o f g o l d c o n t a i n e d i n t h i s z o n e : V a l u e = 0.05271 x 202,100 = $10,650.00. E. DISCUSSION AND ECONOMIC S IGNIF ICANCE The f i g u r e d e r i v e d a t above s h o u l d be r e g a r d e d as a m i n i m a l v a l u e f o r t h e f o l l o w i n g r e a s o n s : R e s u l t s f r o m t h e p r o s p e c t h o l e ( T a b l e X IX) i n d i c a t e an i n c r e a s i n g number o f g o l d c o l o u r s w i t h d e p t h - a s i t u a t i o n p r o b a b l y v a l i d f o r t h e r e s t o f t h e b e a c h as w e l l . F u r t h e r m o r e , i t i s f i ke1y t h a t a 215. number o f v e r y f i n e g o l d p a r t i c l e s were l o s t t h r o u g h a e r a t i o n d u r i n g f i e l d - p a n n i n g , o r d i d not s e p a r a t e c l e a n l y f rom t h e he heavy m i n e r a l c o n c e n t r a t e s on t h e S u p e r P a n n e r , T h i s f a c t i s b o r n e o u t by t h e l a c k o f r e s u l t s f r o m e i t h e r t h e c l i f f - f a c e o r L o s t Shoe C r e e k , s i n c e S t e v e n s o n (1936) and o t h e r s r e p o r t t h a t " c o l o u r s c a n be o b t a i n e d a l m o s t anywhere i n t h e g r a v e l s " o f t h e c l i f f - f a c e . Due t o t h e e x p l o r a t o r y n a t u r e o f t h i s s t u d y , t h e e x p e n s e o f f i r e - a s s a y i n g l a r g e b u l k s a m p l e s was no t deemed n e c c e s s a r y . The t e n o r d e r i v e d a t f o r t h e s u r f a c e m a t e r i a l (5.27 I C / c u . y d . ) i s s u b - m a r g i n a l , h o w e v e r , i n c o n s i d e r i n g a c c e s s i b i l i t y t o t h e a r e a , and t h e i m m e d i a t e a b u n d a n c e o f w a t e r , r e - e v a l u a t i o n i n l i g h t o f s i m i l a r l o w - g r a d e p l a c e r d e p o s i t s e l s e w h e r e i s r e q u i r e d . Bateman (1965) r e p o r t s t h a t p a r t o f t h e K l a m a t h M o u n t a i n P l a c e r s , c o n s i s t i n g o f c e m e n t e d M i o c e n e g r a v e l s , were e c o n o m i c a l l y h y d r a u l i c k e d w i t h a t e n o r o f 2 i - 3< i / cu .yd , S i m i l a r l y , some T e r t i a r y S i e r r a Nevada P l a c e r s a v e r a g i n g I O c / c u . y d . , were a l s o e c o n o m i c a l l y m i n e d . I t t h e r e f o r e a p p e a r s l i k e l y , t h a t hy e m p l o y i n g a c h e a p method o f c o n c e n t r a t i o n s u c h as t h e h y d r a u l i c m e t h o d , t h e e n t i r e c a l -c u l a t e d z o n e c o u l d be m i n e d a t a p r o f i t d u r i n g o n e summer s e a s o n . C o n f i r m a t i o n o f t h i s v i e w s h o u l d , h o w e v e r , f i r s t be s o u g h t t h r o u g h a d e t a i l e d s a m p l i n g p r o g r a m c o n d u c t e d i n t h r e e d i m e n s i o n s . A p o i n t i n f a v o u r o f t h i s t y p e o f m i n i n g , i s t h a t w i t h t h e p a s s i n g o f w i n t e r , t h e b e a c h w o u l d be n a t u r a l l y 216 . r e s t o r e d t o t h e s a t i s f a c t i o n o f c o n s e r v a t i o n i s t s . The h i g h s u r f i c i a l v a l u e s o b t a i n e d by Do lmage ( 1 9 1 9 ) , and i n d e p t h by e a r l y p r o s p e c t o r s and S t e v e n s o n ( 1 9 3 6 ) , was a r e s u l t o f c o n c e n t r a t i o n o v e r h u n d r e d s o f y e a r s due t o t h e c o n -t i n u a l " j i g g i n g " a c t i o n o f t h e s u r f . Low s u r f i c i a l v a l u e s o b -t a i n e d i n t h e p r e s e n t s t u d y s u g g e s t t h a t most o f t h e g o l d has a l r e a d y b e e n t a k e n , and t h e r e f o r e t h e d e p o s i t w o u l d a p p e a r t o be c a p a b l e o f s u p p o r t i n g o n l y a s i n g l e s e a s o n ' s w o r k . C o n c e r n i n g m a g n e t i t e e s t i m a t e s shown i n t h e r i g h t -hand c o l u m n o f T a b l e X I X , a p o s i t i v e c o r r e l a t i o n i s i n d i c a t e d w i t h g o l d i n s a m p l e s f r o m B e a c h (berm) and t h e p r o s p e c t h o l e . F u r t h e r m o r e , H o l l a n d and N a s m i t h (1958) r e p o r t t h a t t h e b e a c h i s most c o n c e n t r a t e d "w i th m a g n e t i t e a l o n g t h e b a c k s h o r e , b e t w e e n berm c r e s t and c l i f f b a s e ( a p p r o x i m a t e l y 100 f e e t ) . D e p e n d i n g on a d e t a i l e d q u a n t i t a t i v e e x a m i n a t i o n o f t h e m a g n e t i t e c o n -t e n t i n t h e c a l c u l a t e d z o n e , a p r o f i t a b l e b y - p r o d u c t t o g o l d m i n i n g s u c h as t h i s , c o u l d e l e v a t e t h e s t a t u s o f t h e m i n i n g p r o p o s i t i o n as a w h o l e . The o n l y o t h e r m i n e r a l o f p o s s i b l e e c o n o m i c s i g n i f i -c a n c e f o u n d t o be c o n c e n t r a t e d on t h e b a c k s h o r e , was z i r c o n ( T a b l e V I ) . F i n a l l y , a s m a l l q u a n t i t y o f p l a t i n u m has b e e n r e p o r t e d t o o c c u r w i t h t h e g o l d by a l o c a l m i n i n g company who r e c e n t l y e x a m i n e d t h e p r o p e r t y . F. SOURCE OF GOLD AND POSS IBLE 0FFSH0KE PLACER DEPOSITS S e v e r a l g o l d - b e a r i n g q u a r t z v e i n s were m i n e d a l o n g t h e Kennedy R i v e r a t t h e t u r n o f t h e c e n t u r y , T h e s e o c c u r r e n -c e s a r e u n i q u e t o t h i s p a r t o f t h e west c o a s t ( D o l m a g e , 1 9 2 0 ) , and as p o s t u l a t e d by h i m . a l m o s t c e r t a i n l y g a v e r i s e t o t h e b e a c h p l a c e r s a t Wreck Bay* S t e v e n s o n (1936) n o t i c e d t h e s h a l l o w d e p r e s s i o n i n c l i f f t o p e l e v a t i o n 1000 f e e t n o r t h w e s t o f t h e mouth o f L o s t Shoe C r e e k (Map l ) „ He s u g g e s t e d t h a t t h e c o n t i n u e n c e o f t h i s d e p r e s s i o n i n l a n d p o s s i b l y r e p r e s e n t s t h e o r i g i n a l s t r e a m bed o f L o s t Shoe C r e e k , p r i o r t o c o a s t a l u p -l i f t . The l i k e l i h o o d o f t h i s c h a n n e l b e i n g the c o u r s e o f g o l d t r a n s p o r t a t i o n f r o m t h e h i n t e r l a n d i s , h o w e v e r , most i m p r o b a b l s i n c e t h e f i n e g o l d i s d i s p e r s e d t h r o u g h o u t t h e g I a c i o f I u v i a I g r a v e l s . P a y - s t r e a k s may w e l l e x i s t i n t h e g r a v e l s , bu t t h e i r s e a r c h w o u l d be e x t r e m e l y d i f f i c u l t and c o s t l y * E v i d e n c e f o r t h e e x i s t e n c e o f an o f f s h o r e p l a c e r was d e r i v e d a t f r o m two i n d e p e n d e n t s t u d i e s : ( i ) A m i n o r mode i n t h e v e r y f i n e s a n d f r a c t i o n ( 0 . 0 6 2 5 mm to 0 .105 mm), w h i c h c o n t a i n e d most o f t h e h e a v y m i n e r a l s , was f o u n d t o c h a r a c t e r i z e s a m p l e s c o l l e c t e d a l o n g t h e 20 f a t h o m l i n e ( s e e c h a p t e r on SEDIMENT S I ZE ANALYSES, T a b l e V I ) . ( i i ) P e t r o l o g i c e x a m i n a -t i o n o f t h i s s i z e f r a c t i o n i n s a m p l e s B -19 ( m i d d l e o f Wreck Bay - Map I ) , OS-k (20 f a t h o m l i n e - Map 2 ) , and 0 S - I 6 (60 f a t h o m s - Map 2 ) , r e v e a l e d t h a t 0S-4 c o n t a i n e d f i v e t i m e s as much m a g n e t i t e as t h e o t h e r two s a m p l e s ( T a b l e V I ) . I t a l s o p o s s e s s e d a h i g h e r p r o p o r t i o n o f o t h e r heavy m i n e e a l s , name l y n o n - m a g n e t i c o p a q u e s , g a r n e t e p i d o t e , p y r o x e n e and h o r n b l e n d e , 2I'8. bu t somewhat l e s s z i r c o n ( s e e h e a d i n g on POINT-COUNT A N A L Y S I S ) . G o l d b e a r i n g b e a c h p l a c e r s p r o d u c e d d u r i n g s t i l l -s t a n d s o f s e a l e v e l i n H o l o c e n e t i m e s , a r e known o f f t h e c o a s t o f Nome, A l a s k a , and i n s o u t h e r n O r e g o n . In t h e l a t t e r a r e a , t h r e e z o n e s o f b l a c k s and h a v e been l o c a t e d on t h e c o n t i n e n t a l s h e l f by p o s i t i v e m a g n e t i c r e s p o n s e o f t h e d e p o s i t s ( C h a m b e r s , 1968 ) . They c o n t a i n m a g n e t i t e , i l m e n i t e , c h r o m i t e and g o l d , and o c c u r a t kO, 2 3 , and 10 f a t h o m s . The f a c t t h a t t h e i n d i -c a t e d Wreck Bay o f f s h o r e p l a c e r c o r r e s p o n d s c l o s e l y i n d e p t h t o t h e Oregon 23 f a t h o m p l a c e r i s p r o b a b l y f o r t u i t o u s , s i n c e p o s t - P l e i s t o c e n e i s o s t a t i c a d j u s t m e n t s o f t h e c r u s t i n t h e two r e g i o n s h a v e not b e e n t h e same. 219. Env i ronment Samp 1e Number G o l d " c o l o u r s V L a r g e 4 0 0 - 2 0 0 Medi um 2 0 0 - IOQM-Sma 1 1 < i oo> T o t a l M a g n e t i t e BEACH (berm) (Map r ( n o r t h w e s t o f r i v e r ) * ! ( L o s t Shoe C r e e k ) y ( s o u t h e a s t ! o f r i v e r ) ( Sand P o i n t ) - -) NWR-6a IWk-5a NWR-4a NWK-3a NWR-2a NV.'R- 1 a 'S ZR~! a S c . R - 2a S E R - 3 a SEK~4a S E R - 5 a tSEK-6a S E K - 7 a S £ R - 8 a 1 j i 3 1 1 2 6 6 1 5 4 5 1 1 1 3 12 7 3 1 3 4 4 3 2 6 18 13 4 3 8 3 8 9 4 1 1 * * •kicic icicic ieick ickic ickk •kick •kick ickic ic ic •k ic C L I F F FACE GLAC IOFLUV IAL OUTWASH (Map 1 ) -•k * •k-k ic* •k-kic „ . ( . . . ' . •kick ( Sand P o i n t ) — C -2 C-3 C-5 C-6 C - 7 --LOST SHOE CREEK (F i g „ 5) LSC-3 LSC-6 L S C - 9 L S C - 12 --- -ickic •k •k LONG BEACH (Map 2) LB - ! !_3-3 LB - 4 L B - 5 --- -•k •k •k * PROSPECT HOLE P - l P-2 P-3 P-4 1 1 2 1 2 3 ic •kit x M a g n e t i t e c o n t e n t e s t i m a t e d v i s u a l l y f r o m p a n n e d c o n c e n t r a t e * = l i t t l e (^10%) T a b l e X IX . * * = f a i r (10 - 30%) G o i d and M a g n e t i e f r o m F i v e a b u n d a n t ( 30%) E n v i r o n m e n t s a t Wreck Bay , 220 . P l a t e 22 . P h o t o m i c r o g r a p h o f t h e l a r g e s t g o l d " c o l o u r s " o b t a i n e d f r o m Beach (berm) and P r o s p e c t H o l e s a m p l e s . 221. P l a t e 23a. View o f the f o r e s h o r e from the c l i f f edge between P r o f i l e B and the mouth o f Lost Shoe Creek. The photograph was taken dur ing the w in te r o f 1968/69. Compare the dark c o l o u r e d m a t e r i a l on the f o r e -shore (b lack sand) with l i g h t m a t e r i a l p resent dur ing the summer ( P l a t e 18b). P l a t e 23b. Prospect ho le l oca ted near P r o f i l e D, and j u s t landward o f the w in te r berm c r e s t . The measuring s t a f f i s graduated in tenths o f a f o o t . The sampl ing channel i s v i s i b l e to the r i g h t o f the measuring s t a f f . Note a l t e r n a t i n g g rave l and sand ho r i zon s in the waI I o f the ho Ie„ 222. X I I I . HARINE L I F E A. INTRODUCTION T a b l e XX i s a l i s t o f a n i m a l m a r i n e l i f e c o l l e c t e d , o r o b s e r v e d , f r o m Wreck Bay and v i c i n i t y d u r i n g t h e summer o f 1968. The i n t r a t i d a l z o n e c o n s i s t i n g o f s andy b e a c h e s and r o c k y s h o r e s , p r o v i d e d by f a r t h e most i n t e r t e b r a t e s ; a few s p e c i m e n s f r om t h e n e r i t i c e n v i r o n m e n t were o b t a i n e d d u r i n g s e d i m e n t s a m p l i n g i n t h e bay and o f f s h o r e . The l i s t i s by no means a c o m p l e t e s y n o p s i s o f l o c a l m a r i n e f a u n a , b u t does r e -p r e s e n t an o u t l i n e o f t h e more common s p e c i e s . B. INTRATIDAL ZONE I. SANDY BEACHES At Wreck Bay t h e b e a c h i s v i r t u a l l y b a r r e n , e x c e p t f o r t h e two d i s t a l e n d s , t h e n o r t h w e s t and s o u t h e a s t c o r n e r s , The f o r m e r a r e a i s most p r o t e c t e d f r o m w a v e s , and s h e l l s c o l -l e c t e d t h e r e u s u a l l y show l i t t l e damage. The s o u t h e a s t c o r n e r i s a more a c t i v e h y d r o d y n a m i c e n v i r o n m e n t , and i s c h a r a c t e r i z e d by s h e l l - h a s h r a n g i n g f r om 0 .5 t o 4 . 0 mm i n g r a i n s i z e . C lams and o t h e r m o l l u s c s h a v e b e e n r e p o r t e d f r o m t h i s a r e a as w e l l . In t h e s m a l l b e a c h s e c t i o n b e t w e e n P r o f i l e A and Q u i s ' t i s P o i n t (Map I ) , B u t t e r and L i t t l e - n e c k C l ams a r e p a r t i c u l a r l y common. T h e i r e x i s t e n c e t h e r e w o u l d a p p e a r t o be t h r e a t e n e d by c a m p e r s , who v i g o r o u s l y hun t them d u r i n g t h e summer f o r t h e i r f o o d v a l u e . H o w e v e r , a v a s t p i l e o f s h e l l s j u s t a b o v e t h e c l i f f , a t t h e s i t e o f an o l d i n d i a n v i l l a g e , 223. i n d i c a t e s t h e i r p e r s i s t e n c e and d u r a b i l i t y i n t h i s e n v i r o n m e n t . A l s o p r e s e n t h e r e , bu t l e s s common, a r e C o c k l e s , Red T u r b a n s and P u r p I e 0 1 i v e s , Sand F l e a s o c c u r o v e r most o f t h e b e a c h , e x c e p t where t h e f o r e s h o r e i s g r a v e i l y . They a r e p a r t i c u l a r l y a b u n -d a n t i n t i d e - p o o l s a r o u n d b o u l d e r s i n t h e n o r t h w e s t c o r n e r o f t h e b e a c h , and a r e c a p a b l e o f i n f l i c t i n g p a i n f u l b i t e s w h i c h b l e e d p r o f u s e l y . Red worms o c c u r j u s t b e n e a t h t h e s and s u r f a c e . They m e a s u r e up t o 5 cms l o n g , and where t h e f o r e s h o r e i s d r y , t h e y r e n d e r i t s s u r f a c e f u l l o f t i n y h o l e s ( P l a t e s 2 4 a ) . Ravens e a g e r l y s e e k them f o r f o o d , by c h o p p i n g up t h e b e a c h s u r f a c e w i t h t h e i r b e a k s ( P l a t e 2 4 b ) . How t h e worms s u r v i v e i n t e n s e s c o u r i n g o f t h e backwash w i t h e a c h t i d a l c y c l e , i s u n -known. P r e s u m a b l y t h e y m i g r a t e d e e p e r i n t o t h e s and t o e s c a p e i t s d e s t r u c t i v e e f f e c t . R a z o r C l am s h e l l s , Dead M a n ' s F i n g e r s ( s p o n g e ) , c a r a p a c e s f r o m E d i b l e C r a b s , and f r a g m e n t s o f M o t t l e d S t a r s , a r e o c c a s i o n a l l y washed up a t v a r i o u s p l a c e s a l o n g t h e b e a c h . Sand d o l l a r s were f o u n d i n o n l y o n e a r e a a l o n g t h e c o a s t , a t P a r a d i s e B e a c h , w h i c h i s l o c a t e d a few m i l e s s o u t h o f T o f i n o . 2. ROCKY SHOKES The Wreck Bay e n v i r o n m e n t c o n s i s t s o f f o u r d i s t i n c t r e g i o n s : Q u i s i t i s P o i n t , Wya P o i n t , F l o r e n c i a I s l a n d , and S e a l Rock . 224 Q u i s i t i s P o i n t i s c h a r a c t e r i z e d by an a b u n d a n c e o f l i m p e t s , B l u e M u s s e l s and A c o r n B a r n a c l e s ; t h e l a t t e r two c o m p l e t e l y o b s c u r i n g a few i s o l a t e d b o u l d e r s on t h e a d j a c e n t b e a c h . T e s t s o f a n i m a l s no t a c t u a l l y s een a l i v e on t h e r o c k s , b u t f o u n d i n n e a r b y t i d a l p o o l s , i n c l u d e : Hooked S l i p p e r S n a i l s , B l a c k Top S h e l l s ( i n v a r i a b l y h o u s i n g G r a n u l a r H e r m i t C r a b s ) , S l e n d e r B i t t i u m , L i r u l a t e M a r g a r i t e s , C h a n n e l e d Dog W h e l k s , and W r i n k l e d P u r p l e s . Wya P o i n t p o s s e s s e s a b u n d a n t B l u e M u s s e l s and A c o r n B a r n a c l e s , and a s h o r t d i s t a n c e d o w n c o a s t f r o m Wreck B a y , Goose B a r n a c l e s t o o become common. N o r t h e r n A b a l o n e has been r e p o r t e d f r o m r o c k s e n c l o s i n g t h e p o c k e t b e a c h , b u t o n l y a few s h e l l f r a g m e n t s were a c t u a l l y r e c o v e r e d . F l o r e n c i a I s l a n d s u p p o r t s i n v e r t e b r a t e f a u n a o n l y on t h e p r o t e c t e d s i d e f a c i n g i n t o t h e b a y . T h r e e s m a l l b e a c h e s o f s h e l l - h a s h e x i s t a b o v e t h e h i g h - t i d e mark on t h i s s i d e o f t h e i s l a n d (Map I ) , and d o u b t l e s s , were c r e a t e d by w i n t e r s t o r m w a v e s . P a r t i c u l a r l y common i n t h i s d e b r i s a r e B l u e M u s s e l S h e l l s (some l o n g e r t h a n 8 i n c h e s ) , W e a t h e r v a n e S c a l l o p s , P u r p l e - h i n g e d Rock S c a l l o p s , L e a f y H o r n m o u t h s , P u r p l e O l i v e s , and C a r p e n t e r Dwar f T u r b a n s , S e a l Rock i s p r a c t i c a l l y b a r r e n e x c e p t f o r a few l i m p e t s . I t d o e s , h o w e v e r , s u p p o r t a f a m i l y o f H a i r S e a l s , n u m b e r i n g abou t e i g h t , who o c c a s i o n a l l y r ange down t o t h e s o u t h e a s t c o r n e r o f t h e b a y , and o u t to F l o r e n c i a I s l a n d . 225 . Wor th m e n t i o n i n g h e r e i s a c o l o n y o f N o r t h e r n Sea L i o n , w h i c h p o p u l a t e o n e o f t h e s m a l l i s l a n d s s o u t h o f T o f i n o . They were n e v e r s e e n a t Wreck B a y , b u t . p e r i o d i c a l l y a d e a d a n i m a l w o u l d wash up o n t o t h e n o r t h e r n p a r t o f Long B e a c h . U b i q u i t o u s a l o n g t h e r o c k y s h o r e s a r e P u r p l e and O c h r e S t a r f i s h , and t h e somewhat l e s s common S u n f l o w e r S t a r s . L e a t h e r C h i t o n s , P u r p l e and G r e e n Sea U r c h i n s , and G r e e n Anemones i n h a b i t i n t e r t i d a l p o o l s i n r o c k c r e v i c e s a l l a l o n g t h e c o a s t . On F l o r e n c i a I s l a n d , Sea U r c h i n s have c a r v e d numerous round h o l e s i n t o t h e r o c k , some o f w h i c h e x c e e d I i n c h i n d e p t h , C. NERIT1C ZONE 1. BENTHOS S e v e r a l s a m p l e s c o l l e c t e d i n t h e bay y i e l d e d L i t t l e O l i v e s and baby C l a m s . Muds f r o m t h e o f f s h o r e t r o u g h c o n t a i n e d Sea Cucumber s and U b i q u i t o u s B r i t t l e S t a r s . Be tween t h e s e two a r e a s , s a m p l e s OS-I t o OS-9 (Map 2) a l l c o n t a i n e d some s h e l l d e b r i s , m o s t l y b i v a l v e s , p a r t i c u l a r l y s a m p l e OS-9 w h i c h c o n -t a i n e d an e x c e s s o f 50% s h e l l s . I n c l u d e d i n t h e l a t t e r were W e a t h e r v a n e S c a l l o p s , C l a m s , P u r p l e U r c h i n s p i n e s , S l e n d e r Blttium/Blue M u s s e l and B a r n a c l e f r a g m e n t s . 2. NEKTON On t h e 2 8 t h J u l y 1968, a number o f Humpback Wha le were o b s e r v e d s o u n d i n g i n t h e bay j u s t n o r t h o f S e a l Rock . W h i l e e c h o - s o u n d i n g t h e bay i n e a r l y J u l y , s c o r e s o f f i s h 226^ ( p r o b a b l y s a lmon ) were s een l e a p i n g f r o m t h e w a t e r a t t h e s o u t h s i d e o f F l o r e n c i a I s l a n d . D. LAND MAMMALS, SEA BIRD AND SEA WEED B l a c k B e a r a r e common a l o n g L o s t Shoe C r e e k , where b e r r i e s g row i n p r o f u s i o n , and R a c c o o n were o f t e n s e e n t h e r e as w e l l . M i n k were f r e q u e n t l y s een r u n n i n g a l o n g t h e s h o r e -l i n e a t t h e w a t e r s e d g e , p a r t i c u l a r l y on t h e s o u t h e a s t p a r t o f t h e b e a c h . B i r d s s e e n i n c l u d e d t h e B a l d E a g l e , R a v e n s , B a i r d Sand P i p e r s , B l a c k O y s t e r C a t c h e r s and G l a u c o u s - w i n g e d G u l l s . The l a t t e r two a r e e s p e c i a l l y common on F l o r e n c i a I s l a n d , and t h e b a r e r o c k on t h e s e a w a r d s i d e o f t h e i s l a n d s e r v e s as a n e s t i n g g r o u n d f o r h u n d r e d s o f g u l l s . S e v e r a l v a r i e t i e s o f seaweed t h r i v e i n Wreck B a y , t h e most i m p r e s s i v e b e i n g K e l p , w h i c h grows i n t h i c k beds o v e r b o u l d e r a r e a s l y i n g c l o s e t o s h o r e (Map I ) . D u r i n g A u g u s t 1968, a s t o r m t o r e v a s t q u a n t i t i e s o f t h e weed l o o s e f r o m t h e i r a n c h o r s , and o p p o s i n g l i t t o r a l c u r r e n t s d e p o s i t e d i t i n huge p i l e s on t h e b e a c h ( P l a t e 2 5 a ) . Some o f them s t i l l had l a r g e c o b b l e s f i r m l y a t t a c h e d t o t h e i r h o l d f a s t s ( P l a t e 2 5 b ) . 227. T a b l e XX. L i s t o f A n i m a l M a r i n e L i f e C o l l e c t e d o r O b s e r v e d a t Wreck B a y . MOLLUSCA GASTROPODA Acmaea i n s t a b i 1 i s ( G o u l d ) A. m i t r a F s c h s c h o l t z A. p e l t a E s c h s c h o l t z p e r s o n a E s c h s c h o l t z s cu tum E s c h s c h o l t z A. t e s t u d i n a I i s D i o d o r a a s p e r a E s c h s c h o l t z C r e p i d u l a a d u n c a Sowerby H a l i o t i s k a m t s c h a t k a n a J o n a s T e g u l a f u n i b r a l ? s (A. Adams) T . pu I I i go GmeIi n C a l I i o s t o m a l i q a t u m G o u l d M a r g a r i t e s l i r u l a t u s ( C a r p e n t e r ) MV he Ii c ? nus P h i p p s A s t r a e a g i b b e r o s a Di I Iwyn Homalopoma c a r p e n t e r l ( P i I s b u r y ) S e a r Ies i a d i r a Reeve N a s s a r i u s f o s s a t u s Gou Id Tha i s I ame1 lo sa GmeIi n 01 i v e l l a b i p l i c a t a Sowerby 0. b a e t i c a C a r p e n t e r C e r a t o s t o m a f o i i a t a GmeIi n B i t t i u m a t t e n u a t u m C a r p e n t e r PELECYPODA My11 lus edu1 i s L i n n a e u s Sax ldomus g i g a n t e u s ( D e s h a y e s ) P r o t o t h a c a s t a m i n e a ( C o n r a d ) Si 1? qua p a t u I a ( D i x o n ) C l i n o c a r d i u m n u t t a l I ? ( C o n r a d ) P e c t e n c a u r i n u s Gou Id H i n n i t e s m u l t i r u q o s U s ( G a l e ) AMPHIN.EURA K a t h a r i n a t u n i c a t a Wood ARTHftOPODA CKUSTACEA B a l a n u s c a r i o s u s ( P e l l a s ) Lepa s a n a t j f e r a L i n n a e u s C a n c e r magi s t e r Dana i ? a g u r u s g r a n o s i m a n u s ( S t i m s o n ) O r c h e s t o i d e a C a l i f o r n f a n a U n s t a b l e L i m p e t W h i t e c a p L i m p e t S h i e l d L i m p e t Mask L i m p e t P l a t e L i m p e t Rough K e y h o I e L i m p e t Hooked S.I i p p e r S n a i I N o r t h e r n A b a l o n e B I a c k T o p - s h e l I Dusky T u r b a n B I ue T o p - s h e I I L i ru I a t e M a r g a r i t e Smooth M a r g a r i t e Red T u r b a n C a r p e n t e r Dwarf Tu rban Di re Whe lk C h a n n e l e d Dog Whe lk W r i n k l e d P u r p l e Pu r p I e 01i v e L i t t l e 0 1 i v e L e a f y Hornmouth S l e n d e r B i t t i u m B Iue Musse I B u t t e r C l am L i t t I e - n e c k CI am R a z o r C l am Cock Ie W e a t h e r v a n e Sea I l op Pu r p I e - h i nged Rock Sea I l op L e a t h e r C h i t o n A c o r n B a r n a c l e Goo se B a r n a c l e E d i b l e C r a b G r a n u l a r H e r m i t C rab Sand F l e a 228. ECHINODERMATA ASTEKOIDEA P i s a s t e r o c h r a c e u s ( B r a n d t ) P y c n o p o d i a h e ! { a n t h o i d e s ( B r a n d t ) E v a s t e r i a s t r o s c h e l i i ( S t i m s o n ) O p h i o p h o l i s a c u l e a t a ECHINOIDEA S t r o n q v l o c e n t r o t u s d r o b a c h ? e n s i s ( M u ! l e r ) D.en'draster e x c e n t r i c u s . E s c h s c h o I t z HOLOTHUROI DEA L e p t o s v n a p t a a l b i c a n s COELENTERATA ANTHOZOA A n t h o p l e u r a x a n t h o q r a m m i c a PORIFERA DEMCSPONGIAE HADROMERINA P o l y m a s t i a p a c h y m a s t J a Pu rp I e o r O c h r e S t a r f i sh S u n f l o w e r S t a r M o t t l e d S t a r Ubi qu i t o u s B r i t t l e S t a r G r e e n Sea U r c h i n Sand Do I I a r Sea Cucumber G r e e n Anemone Dead M a n ' s F i n g e r s ANNELIDA POLYCHAETA T h o r a c o p h e l ? a m u c r o n a t a Red Worm MAMMAL I A Phoca v i t u I i na L i n n a e u s E u m e t o p i a s j u b a t a ( S c h r e b e r ) M e q a p t e r a n o v a e a n g l i a e ( B o r o w s k i ) H a l r Sea I N o r t h e r n Sea L i o n Humpback Wha le 229 . P l a t e 2 4 a . A Red Worm i s shown on t h e n o t e b o o k , and t h e mesh o f t i n y h o l e s i n t h e b e a c h s u r f a c e i s t h e r e s u l t o f t h e i r b u r r o w i n g . The l ong t r a c k s on t h e s and s u r f a c e a r e s n a i l m a r k i n g s . P l a t e 24b. Raven d i g g i n g s f o r Red Worms. 230. P l a t e 2 5 a . P i l e s o f d e l p d e p o s i t e d on t h e f o r e s h o r e where o p p o s i n g l i t t o r a ' c u r r e n t s c o n v e r g e d . The p h o t o g r a p h was t a k o n on t h e 19th A u g u s t I 9 D 8 , j u s t a f t e r t h e Summer S t o r m . Note t h e i n f l u e n c e o f t h e k e l p p i l e s on f o r e s h o r e e r o s i o n . P l a t e 25b. K e l p t e r n from - b ^ M ' . r ' ;Jr !n t h e bay by l a r g e s t o r m w a v e s . The c o b b l e s a t t a - - ' .d t o t h e k e l p h o l d f a s t s were s i m i l a r t o t h o s e i n t h e g I a c i o f I u v i a I o u t w a s h . 231 . REFERENCES A n d e r s o n , F . E . , 1 9 6 8 , Seaward t e r m i n u s o f t h e v a s h o n c o n t i n e n t a l c l a c i e r i n t h e S t r a i t o f J u a n de F u c a . M a r i n e G e o l . , v . 6 , p p . 4 1 9 - 4 3 3 . A u b o u l n , J . , 1965. G e o s y n c I i nes.. E l s e v i e r Pub I . C o . , New Y o r k , 288 p. B a g n o l d , R . A . , 1 9 4 0 . B e a c h f o r m a t i o n by waves ; some model e x p e r i m e n t s i n a wave t a n k . J . I n s t . C i v . E n o r s . , v . I , P a p e r 5 2 3 7 , p , 2 7 - 5 2 „ B a s c o m , W . N . , 1951. The r e l a t i o n s h i p b e t w e e n sand s i z e and b e a c h - f a c e s l o p e . T r a n s . A m e r . G e o p h y s . U n i o n , v o l . 3 2 , p. 866-874,, , 1964 . Waves and b e a c h e s . D o u b l e d a y and C o . , N . Y . 2 6 7 p . B a t e m a n , A . M . , 1 9 6 5 . E c o n o m i c m i n e r a l d e p o s i t s . J o h n W i l e y & Sons I n c . , 916 p, B h o o j e d h u r , S . , 1 9 6 9 . G e n e s i s o f a p o d z o l s e q u e n c e on t h e west c o a s t o f V a n c o u v e r I s l a n d . U n p u b l i s h e d M . S c . t h e s i s , D e p t . o f S o i l S c i e n c e , U . B . C , V a n c o u v e r . B o o n , J . D. , I'I I , 1968. T r e n d s u r f a c e a n a l y s i s o f s and t r a c e r d i s -t r i b u t i o n s on a c a r b o n a t e b e a c h , B i m i n i , B.W.I . J . G e o l . , v . 7 6 , p p . 7 1 - 8 7 . Bowen, A . J . , 1 9 6 9 . R i p c u r r e n t s , P a r t I - T h e o r e t i c a l i n v e s t i -g a t i o n s . J . G e o p h y s . R e s . , v o l . 7 4 , n o . 2 3 , p . 5 4 6 7 - 5 4 7 8 . f a n c j 1 nman, D . L . , 1 9 6 9 . R i p c u r r e n t s , P a r t 2 - L a b o r a -t o r y and f i e l d o b s e r v a t i o n s . J . G e o p h y s . R e s . , v . 7 4 , n o . 2 3 , p . 5 4 7 9 - 5 4 9 0 . C a l d w e l l , J . M . , 1956. Wave a c t i o n and sand movement n e a r A n a h e i m B a y , C a l i f o r n i a . B . E . B . T e c h . M e m o . N o . 6 8 , p . 1 - 1 9 . C a n a d i a n H y d r o g r a p h i c S e r v i c e , 1968. T i d e and c u r r e n t t a b l e s , v . 6 . C h a m b e r s , D . , 1 9 6 8 . A n c i e n t s h o r e l i n e s and p o t e n t i a l e c o n o m i c p l a c e r d e p o s i t s o f f S o u t h e r n O r e g o n . 0 c e a n r C o n f . , U n i v . o f W a s h . , S e s s i o n IV, N o . I , ~ F e b . 1 0 , 1 9 6 8 . C h a p p e l l , J . , 1 9 6 7 . R e c o g n i z i n g f o s s i l s t r a n d l i n e s f r om c r a i n -s i z e a n a l y s i s . J . S e d . P e t r . , v . 3 7 , No.I , p . 1 5 7 - 1 6 5 . 232. C l o u d , P . E . , J r . , 1 9 6 6 . B e a c h c u s p s : R e s p o n s e t o P l a t e a u ' s R u l e ? S c i e n c e , v , 154, p. 890-39 I. C u r r a y , J . R . , I960. T r a c i n g s e d i m e n t mas ses by g r a i n s i z e modes. I n t . G e o I . C o n q r . , 2 1 s t S e s s i o n N o r d e n , C o p e n h a g e n , p . 1 1 9 - 1 3 0 . Do I mage, V . , 1 9 1 9 . B e r k l e y S o u n d , V a n c o u v e r I s l a n d , B . C . B . C M i n i s t e r o f M i n e s Annua l R e p o r t , p . l 2 B - 2 0 B . , 1920, West c o a s t o f V a n c o u v e r I s l a n d be tween B a r k l e y and Q u a t s i n o S o u n d s . B . C . M i n i s t e r o f M i n e s Annua l R e p o r t , p . l 2 A - 2 2 A . E a s t w o o d , G . E . P . , 1 9 6 3 . G e o l o g y o f t h e Kennedy L a k e a r e a . B .C . D e p t . o f M i n e s and P e t r . R e s . , B u l l . N o . 5 i > , 63p. E m e r y , K . O . , and F o s t e r , J . F . , 1 9 4 8 . Wa te r t a b l e s i n m a r i n e b e a c h e s . J . M a r . R e s . , v . 7 , N o . 3 , p.644-654. E m e r y , K . O . , I960. The sea o f f s o u t h e r n C a l i f o r n i a . J o h n W i l e y and Sons I n c . , 366 p. F o l k , R . L . , 1 9 6 6 . A r e v i e w o f g r a i n - s i z e p a r a m e t e r s . S e d i m e n t o -l o g y , v . 6 , p .73-93 . } 1968. P e t r o l o g y o f s e d i m e n t a r y r o c k s . H e m p h i l l ' s , T e x a s , 170 p. F r i e d m a n , G . M , , l 9 6 l . D i s t i n c t i o n b e t w e e n d u n e , b e a c h and r i v e r s and s f r om t h e i r t e x t u r a l c h a r a c t e r i s t i c s . J . S e d . P e t r . , v . 3 l , p . 5 1 4 - 5 2 9 . - , 1 9 6 2 . On s o r t i n g , s o r t i n g c o e f f i c i e n t s and l o g -n o r m a l i t y o f t h e o r a i n - s i z e d i s t r i b u t i o n o f s a n d -s t o n e s . J . G e o l . , v.7 0 , N o . 6 , p . 7 3 7 - 7 5 3 . - , 1 9 6 7 , Dynamic p r o c e s s e s s and s t a t i s t i c a l p a r a m e t e r s c o m p a r e d f o r s i z e f r e q u e n c y d i s t r i b u t i o n o f b e a c h and r i v e r s a n d s . J . Sed..Pet r. , v . 3 7 , p . 3 2 7 - 3 5 4 . G i l b e r t , G . K . , 1 9 1 4 . The t r a n s p o r t a t i o n o f d e b r i s by r u n n i n g w a t e r . U . S . G e o I . S u r v . , P r o f . P a p e r 86, 263 p. G r a n t , U . S . , 1 9 4 8 . I n f l u e n c e o f t h e w a t e r t a b l e on b e a c h a g g r a d a t i o n and d e g r a d a t i o n . J . M a r . R e s . , v . 7 , p . 6 5 5 - 6 6 0 . G r e e n w o o d , B . , 1 9 6 9 . S e d i m e n t p a r a m e t e r s and e n v i r o n m e n t d i s c r i -m i n a t i o n : An a p p l i c a t i o n o f m u l t i v a r i a t e s t a t i s t i c s . C a n . J . E a r t h S c . , v . 6 , p .1347 -1353. 233. G r i g g s , G . B . , and K u l m , L . D . , 1969. G l a c i a l m a r i n e s e d i m e n t s f r om t h e n o r t h e a s t P a c i f i c . J . S e d . P e t r . , v . 3 9 , p . 1 1 4 2 - 1 1 4 8 . G r i m , R . E . , 1958. C o n c e p t o f d i a q e n e s i s i n a r g i l l a c e o u s s e d i ' m e n t s . A . A . P . G . , v . 4 2 ~ p . 2 4 6 - 2 5 3 . 1968. C l a y m i n e r a l o g y . M c G r a w - H i l l Book C o . , 596 p. G r o s s , M . G . , McManus, D .A . , and L i n g , H - Y . , 1967. C o n t i n e n t a l s h e l f s e d i m e n t , n o r t h w e s t e r n U n i t e d S t a t e s . J . S e d . P e t r . , v . 3 7 , p . 7 9 0 - 7 9 5 -? M o r s e , B . A . , and B a r n e s , C . A . , 1969. Movement o f n e a r - b o t t o m w a t e r s on t h e c o n t i n e n t a l s h e l f o f f n o r t h w e s t e r n U n i t e d S t a t e s . A m e r . G e o p h y s . U n i o n , p . 7 0 4 4 - 7 0 4 7 . H a i l s , J . R . , 1967. S i g n i f i c a n c e o f s t a t i s t i c a l p a r a m e t e r s f o r d i s t i n g u i s h i n g s e d i m e n t a r y e n v i r o n m e n t s i n New S o u t h W a l e s , A u s t r a l i a . J . S e d . P e t r . , v . 3 7 , p . 1 0 5 9 - 1 0 6 9 . 1 a n c j H o y t , J . H . , 1969. The s i g n i f i c a n c e and l i m i t a -t i o n s o f s t a t i s t i c a l p a r a m e t e r s f o r d i s t i n g u i s h i n g a n c i e n t and modern s e d i m e n t a r y e n v i r o n m e n t s o f t h e Lower G e o r g i a c o a s t a l p l a i n . J . S e d . P e t r . , v . 3 9 , p . 5 5 9 - 5 8 0 . H a r r i s o n , W., 1964. B e a c h c h a n g e s a t V i r g i n i a B e a c h , V i r g i n i a . C . E . R . C . , M i s c . P a p e r N o . 6 - 6 4 , p . 1 - 2 5 . H i t e - i n B a t e m a n , A . M . , 1965. E c o n o m i c m i n e r a l d e p o s i t s . J o h n W i l e y and Sons I n c . , 916 p. H o l l a n d , S . S . , and N a s m i t h , H.W., 1958. I n v e s t i g a t i o n o f b e a c h s a n d s . B . C . D e p t . o f M i n e s , M a r c h , 19.58, p . 3 . H o l l a n d , S . S . , 1964. L a n d f o r m s o f B r i t i s h C o l u m b i a : A p h y s i o -g r a p h i c o u t l i n e . B . C . D e p t . o f M i n e s and P e t r . R e s . , Bu i I . N o . 4 8 , 138 p. H o w a r t h , R . J . , 1967. T r e n d s u r f a c e f i t t i n g t o random d a t a -an e x p e r i m e n t a l t e s t . A m e r . J . S c . , v . 2 6 5 , p . 6 1 9 - 6 2 5 . H o y t , J . H . , and H e n r y , J . J . , 1963. Rhomboid r i p p l e m a r k , i n d i -c a t o r o f c u r r e n t d i r e c t i o n and e n v i r o n m e n t . J . S e d . Pet r . , v . 3 3 , p . 6 0 4 - 6 0 8 . I n g l e , J . C . , J r . , 1964. The movement o f b e a c h s a n d . E l s e v i e r Pub I . Co . , 22 I p. 234. Inman, D . L . , 1953- A e r i a l and s e a s o n a l v a r i a t i o n s i n b e a c h and n e a r s h o r e s e d i m e n t s a t La J o l l a , C a l i f o r n i a . B . E . B . Tech.Memo, No .39 , p. I-132. , 1963, J_n: S h e p a r d , F . P . , S u b m a r i n e g e o l o g y . H a r p e r and Row, 555 p. J o h n s o n , D.W., 1919. S h o r e p r o c e s s e s and s h o r e l i n e d e v e l o p m e n t . H a f n e r , New Y o r k , 534 p. J o h n s o n , J . W . , 1956, Dynamic s o f n e a r s h o r e s e d i m e n t movement. A m . A s s . P e t r . G e o I .Bui I., v . 4 0 , p . 2 2 1 1 - 2 2 3 2 . K i n g , L . H . , 1967. Use o f a c o n v e n t i o n a l e c h o - s o u n d e r and t e x -t u r a l a n a l y s e s i n d e l i n e a t i n g s e d i m e n t a r y f a c i e s : S c o t i a n s h e l f . C a n . J . E a r t h S c . , v . 4 , p . 6 9 1 - 7 0 7 . K o l d i j k , W . S . , 1968. On e n v i r o n m e n t s e n s i t i v e o r a i n - s i z e p a r a -m e t e r s . S e d i m e n t o l o g y , v . 1 0 , p . 5 7 - 6 9 . K r u m b e i n , W . C . , and P e t t i j o h n , E . F . , 1938. Manual o f s e d i m e n -t a r y p e t r o g r a p h y . A p p l e t o n - C e n t u r y - C r o f t s , I n c . , 549 p. L e M e h a u t e , B . , and B r e b n e r , A . , 1961. An i n t r o d u c t i o n t o c o a s t a l m o r p h o l o g y and l i t t o r a l p r o c e s s e s . Queens U n i v . C i v i l E n g r . R e p o r t No. 14, 46 p. M c L e a n , R., 1967. P l a n s h a p e and o r i e n t a t i o n o f b e a c h e s a l o n g t h e e a s t c o a s t , S o u t h I s l a n d . New Z e a l a n d G e o g r a p h e r , v . 2 3 , no. I, p. 16 -22 . M o i o l a , R . J . , and W e i s e r , D. , 1968. T e x t u r a l p a r a m e t e r s : an e v a l u a t i o n . J . S e d . P e t r . , v . 3 3 , p . 4 5 - 5 3 . M o t h e r s i l l , J . S . , 1969. A g r a i n s i z e a n a l y s i s o f l o n g s h o r e b a r s and t r o u g h s , L a k e S u p e r i o r , O n t a r i o . J . S e d . P e t r . , v . 3 9 , p. 1317 -1324 . M u l l e r , J . E . , and C a r s o n , D . J . T . , 1969. G e o l o g y and m i n e r a l d e p o s i t s o f A l b e r n i m a p - a r e a , B r i t i s h C o l u m b i a ( 92F ) Geo I . S u r v , C a n a d a P a p e r 6 8 - 5 0 , 52 p. Munk, W.H. - _i_n S h e p a r d , F . P . , 1963. S u b m a r i n e G e o l o g y . H a r p e r and Row, 555 p. N i c h o l s o n , G . , 1966. V a n c o u v e r I s l a n d ' s west c o a s t 1762 -1962 . M o r r i s P r i n t i n g C o . , V i c t o r i a , 356 p. O t v o s , E . G . , J r . , 1964. O b s e r v a t i o n s o f b e a c h c u s p and b e a c h r i d g e f o r m a t i o n on t h e Long I s l a n d S o u n d . J . S e d . P e t r . v . 3 4 , p . 6 0 4 - 6 0 9 . 235. P i e r c e , J .W. , and G o o d , D . K , 1966. F o r t r a n I I p r o g r a m f o r s t a n d a r d s i z e a n a l y s i s o f u n c o n s o l i d a t e d s e d i m e n t s u s i n g an IBM 1620 c o m p u t e r . S t a t e G e o l . S u r v e y , U n i v . o f K a n s a s , L a w r e n c e , S p . P u b l . 28 , 19 p.. P i e r c e , J . W . , and S i e g e l , F . R . , 1969. Q u a n t i f i c a t i o n o f c l a y m i n e r a l s t u d i e s o f s e d i m e n t s and s e d i m e n t a r y r o c k s . J . S e d . P e t r . , v . 3 9 , p . 1 8 7 - 1 9 3 . P i l k e y , O . H . , and R i c h t e r , D.M. , 1964. B e a c h p r o f i l e s o f a G e o r g i a b a r r i e r i s l a n d . U n i v . o f G e o r g i a M a r i n e I n s t . No. 71 , p. I I - 1 9 -R e c t o r , R . L . , 1954. L a b o r a t o r y s t u d y o f e q u i l i b r i a m p r o f i l e s o f b e a c h e s . B . E . B . , T e c h . M e m o . N o . 4 I, 33 p. S h e p a r d , F . P . , and L a F o n d , E . C . , 1940. Sand movement a l o n g t h e S c r i p p s I n s t i t u t e p i e r . A m e r . J . S c i . , v . 2 3 8 , p.212-285. S i l v e s t e r , R., I960. S t a b i l i z a t i o n o f s e d i m e n t a r y c o a s t l i n e s . N a t u r e , v . 1 8 8 , p . 4 6 7 - 4 6 9 . S i m o n s , D .B . , R i c h a r d s o n , E . V . , and N o r d i n , C . F . , 1965. S e d i m e n t a r y s t r u c t u r e s g e n e r a t e d by f l o w i n a l l u v i a l c h a n n e l s . S . E . P . M . Sp .Pub I.No.I 2, p . 3 4 - 5 2 . S t e v e n s o n , J . S . , 1936. Wreck Bay . B . C . M i n i s t e r o f M i n e s Annua l R e p o r t , P a r t F - S p e c i a l R e p o r t . S t r a h l e r , A . N . , I 964 . T i d a I c y c l e o f c h a n g e s i n an e q u i l i b r i a m b e a c h , Sandy Hook , New Y e r s e y . U . S . D e p t . o f N a v y , P r o j . NR 3 8 8 - 0 5 7 , T e c h . R e p . N o . 4 , 51 p. S u t h e r l a n d B r o w n , A . , 1966. T e c t o n i c h i s t o r y o f t h e i n s u l a r b e l t o f B r i t i s h C o l u m b i a . C a n . I n s t . M i n . M e t . , S p e c . v o l . N o . 8 , p . 3 3 - 1 0 0 . W a t t s , G „ M . , and D e a r d u f f , R . F . , 1954. L a b o r a t o r y s t u d y o f e f f e c t o f t i d a l a c t i o n on wave f o rmed b e a c h p r o f i l e s . B . E . B . T e c h . M e m o . N o . 5 2 , 2 1 p. W a t t s , J . S . , and F a u l k n e r , R . E . , 1968. D e s i g n i n g a d r i l l i n g r i c f o r s e v e r e s e a s . Ocean I n d u s t r y , v o l . 3 , n o . 2 , p . 2 3 - 3 7 . 236. W i e g e l , R . L . , P a t r i c k , D .A . , and K i m b e r l e y , H .L . , 1954. Wave l o n g s h o r e c u r r e n t , and b e a c h p r o f i l e r e c o r d s f o r S a n t a M a r g a r i t a R i v e r b e a c h , O c e a n s i d e , C a l i f o r n i a . T r a n s . A m e r . G e o p h y s , U n k o n , v . 3 5 , p . 3 3 7 - 3 9 6 . W r i g h t , F 0 F „ , 1962. The d e v e l o p m e n t and a p p l i c a t i o n o f a f l o u r e s c e n t m a r k i n g t e c h n i q u e f o r t r a c i n g 0 s a n d movements on b e a c h e s , U . S t D e p t . o f N a v y , P r o j . NR388-0 5 7 , T e c h . R e p . N o . 2 , 31 p. Y a s s o , W . E . , 1962. F l o u r e s c e n t c o a t i n g s on c o a r s e s e d i m e n t s : an i n t e g r a t e d s y s t e m . U . S . D e p t . o f N a v y , P r o j . N R 388-0 5 7 , T e c h . R e p . N o , I , 48 p. - , 1964. Geomet ry and d e v e l o p m e n t o f s p i t b a r s h o r e -l i n e s a t H o r s e s h o e C o v e , Sandy Hook , Kevj Y e r s e y . U . S . D e p t . o f N a v y , P r o j . NR 3 8 8 - 0 5 7 , T e c h . R e p . N o . 5 , 106 p. - , 1964. Use o f f l o u r e s c e n t t r a c e r s t o d e t e r m i n e f o r e s h o r e s e d i m e n t t r a n s p o r t , Sandy Hook, New Y e r s e y . U . S . D e p t . o f Navy , P r o j . NR 3 8 8 - 0 5 7 , T e c h . R e p . N o . 6 , 13 p. 237. APPENDIX SEDIMENT SAMPLE COLLECTION A t o t a l o f 135 s e d i m e n t s a m p l e s were c o l l e c t e d f o r l a b o r a t o r y s t u d y . They were p a r t i a l l y u s e d i n t h r e e d i f f e r e n t i n v e s t i g a t i o n s , and w i l l be r e f e r r e d t o u n d e r t h e a p p r o p r i a t e h e a d i ng s : - RECENT SEDIMENTS - P o i n t - c o u n t a n a l y s i s - X - r a y d i f f r a c t i o n a n a l y s i s - SEDIMENT S I ZE ANALYSES - ECONOMIC GEOLOGY In a d d i t i o n t o t h e s e s a m p l e s , 91 s m a l l s a m p l e s were c o l l e c t e d f r o m p r o f i l e r o d - s t a t i o n s s p e c i f i c a l l y t o e x a m i n e s e a s o n a l f o r e s h o r e v a r i a b i l i t y - s ee SEDIMENT S I Z E ANALYSES. A b r i e f d e s c r i p t i o n o f s a m p l e p r o c e d u r e s and l o c a t i o n s a r e g i v e n . F u r t h e r m o r e , i n o r d e r t o a p p r e c i a t e t h e c h a r a c t e r o f m a t e r i a l f r o m t h e d i f f e r e n t e n v i r o n m e n t s , a v e r b a l r a n g e f o r mean and s t a n d a r d d e v i a t i o n i s i n c l u d e d , t h e f o r m e r b e i n g W e n t w o r t h s i z e c l a s s e s ( F o l k , 1 9 6 8 ) , and t h e l a t t e r F r i e d m a n ' s (1962) s o r t i n g d e s i g n a t i o n . The f o l l o w i n g l i s t i s f o r l a r g e s a m p l e s , t h e s m a l l s a m p l e s a r e i n c l u d e d i n t h e BEACH e n v i r o n -ment . F o r c o n v e n i e n c e , t h e e n v i r o n m e n t s h a v e b e e n s e p a r a t e d i n t o two b r o a d c a t a g o r i e s , one e x t e n d i n g p a r a l l e l t o t h e c o a s t f r o m n o r t h w e s t t o s o u t h e a s t , and t h e o t h e r norma l t o t h e c o a s t p a s s i n g t h r o u g h Wreck B a y . 238 . PARALLEL TO COAST LONG BEACH (LB) - Map 2, 5 s a m p l e s , a p p r o x i m a t e l y 1000 gms e a c h . Top one i n c h o f b e a c h s u r f a c e s c r a p e d t o g e t h e r . C o l l e c t e d b e h i n d a p o o r l y d e f i n e d w i n t e r b e r m , e x c e p t L B - 2 w h i c h came f r o m a c o a s t a l d u n e , and L B - 3 f r o m t h e mouth o f Sand H i l l C r e e k . F i n e s a n d : v e r y w e l l t o m o d e r a t e l y w e l l s o r t e d , QU IS IT I S POINT (QP) - F i g u r e 5 , 8 s a m p l e s , a p p r o x i -m a t e l y 1000 gms e a c h , Top one i n c h o f b e a c h s u r f a c e s c r a p e d t o g e t h e r . C o l l e c t e d f r o m s m a l l p o c k e t b e a c h e s i n r o c k c r e v a s s e s . Med ium s and t o g r a n u l e s ; v e r y p o o r l y t o m o d e r a t e l y w e l l s o r t e d . WYA POt NT (WP) - F i g u r e 5, I I s a m p l e s , a p p r o x i m a t e l y 1000 gms e a c h . Top one i n c h o f b e a c h s u r f a c e s c r a p e d t o g e t h e r . C o l l e c t e d f r om s m a l l p o c k e t b e a c h e s i n r o c k c r e v a s s e s . F i n e t o v e r y c o a r s e s a n d ; v e r y we Ii t o m o d e r a t e l y w e l l s o r t e d , NORMAL TO COAST LOST SHOE CREEK (LSC ) - F i g u r e 5, 13 s a m p l e s , a p p r o x i m a t e l y 1000 gms e a c h . C o l l e c t e d f r o m a c t i v e m i d - c h a n n e l s e d i m e n t . S amp le s 800 f e e t a p a r t be tween T o f i n o - U c I u e I e t h i ghway b r i d g e , and r i v e r mouth (2 m i l e s ) . Medium s and t o g r a n u l e s ; m o d e r a t e l y t o v e r y p o o r l y s o r t e d . 239 . C L I F F (C) GLAC !OFLUV IAL OUTWASH - Map I, 6 s a m p l e s , a p p r o x i m a t e l y 1000 gms e a c h . 5 f o o t c h a n n e l s a m p l e s f r o m h a l f w a y up c l i f f - f a c e , e x c e p t C -2 i m m e d i a t e l y a b o v e brown c l a y n e a r t o p o f c l i f f . C l i f f s e c t i o n f r o m P r o f i l e B t o P r o f i l e G (2j m i l e s ) . V e r y c o a r s e s and t o g r a n u l e s ; p o o r l y t o v e r y p o o r l y s o r t e d . GREY CLAY - Map I, 3 s a m p l e s , a p p r o x i m a t e l y 500 gms e a c h . One f o o t c h a n n e l s a m p l e s j u s t a b o v e b a c k s h o r e , e x c e p t C -2 i m m e d i a t e l y b e l o w brown c l a y n e a r t o p o f c l i f f . C l i f f s e c t i o n f r o m P r o f i l e A t o r e g i o n b e h i n d s p i t - b a r (I m i l e ) , . C o h e s i v e , s i l t y , few p e b b l e s . BROWN CLAY - One s a m p l e , a p p r o x i m a t e l y 500 gms. One f o o t c h a n n e l s amp le b e t w e e n g I a c i o f I u v i a I o u t w a s h and g r e y c l a y a t C-2. F r i a b l e , s i l t y , i r o n - o x i de r i n g s , MUDBALL - One s a m p l e , a p p r o x i m a t e l y 1500 gms. C o l l e c t e d a d j a c e n t t o C-3 i n g I a c i o f I u v i a I o u t w a s h . S p h e r o i d a l , s a n d y , b r o w n . BEACH L a r g e s a m p l e s (NWR, S E K ) - Map I, 42 s a m p l e s , a p p r o x i m a t e l y 1000 gms e a c h . Top one i n c h o f b e a c h s u r f a c e s c r a p e d t o g e t h e r . 6 s a m p l e l i n e s n o r t h w e s t , 2kC. and 8 s a m p I e s l i n e s s o u t h e a s t o f L o s t Shoe C r e e k m o u t h , e a c h l i n e c o n t a i n i n g 3 s a m p l e s : B ERM (a) •- C o l l e c t e d on b a c k s h o r e b e h i n d w i n t e r berm c r e s t c V e r y c o a r s e s and t o g r a n u l e s ; v e r y w e l l t o m o d e r a t e l y s o r t e d , MEAN HIGH Ti DE (b) - C o l l e c t e d b e l o w h i g h t i d e swash mark . F i n e t o c o a r s e s a n d ; v e r y w e l l t o p o o r l y s o r t e d . MEAN WATER LEVEL ( c ) - C o l l e c t e d a t B a s c o m ' s (1951) " r e f e r e n c e p o i n t " , a p p r o x i m a t e l y t h e m i d - t i d e l e v e l . F i n e s a n d ; v e r y w e l l t o m o d e r a t e l y s o r t e d . S m a l l s a m p l e s ( p r o f i l e r o d numbers ) - Map I, 91 s a m p l e s , a p p r o x i m a t e l y 100 gms e a c h , 54 f r o m summer f o r e s h o r e and 37 f r o m w i n t e r f o r e s h o r e . F i n e s and t o p e b b l e s ; v e r y w e l l s o r t e d t o e x t r e m e l y p o o r l y so r t e d . BAY (B) - Map I, 25 s a m p l e s , a p p r o x i m a t e l y 500 gms e a c h . S amp led f r o m m o t o r l a u n c h u s i n g D i e t z -L a F o n d , Eckman and Van Veen g r a b s . F i n e t o c o a r s e s a n d ; v e r y w e l l t o e x t r e m e l y p o o r l y s o r t e d , OFFSHORE (CS) - Map 2, 20 s a m p l e s , a p p r o x i m a t e l y o n e c u . f t . e a c h . S a m p l e d f r o m C . N . A . V , L A Y M 0 R E u s i n g P e t t e r s s o n and Van Veen g r a b s . 13 Samp le s s u b - s a m p l e d t o a p p r o x i m a t e l y 1000 gms e a c h ; 2kl. f i n e s and t o c o b b l e s ; v e r y w e l l t o p o o r l y s o r t e d . 7 s a m p l e s s u b - s a m p l e d t o a p p r o x i m a t e l y 500 gms e a c h ; s andy g r e e n - g r e y s i l t . 242. GLOSSARY The f o l l o w i n g l i s t o f t e rms a r e d e f i n e d i n t e r m s o f t h e m e a n i n g s i n w h i c h t h e y have b e e n u s e d i n t h i s t h e s i s : BEACH RIDGE - An e l e v a t e d body o f s e d i m e n t o c c u r r i n g on t h e f o r e s h o r e , and o r i e n t e d p a r a l l e l t o t h e s h o r e l i n e . BEACH RUNNELS - E l e v a t e d b o d i e s o f c o a r s e s e d i m e n t o c c u r r i n g on t h e f o r e s h o r e , and o r i e n t e d a t r i g h t - a n g l e s t o the s h o r e l i n e . They a r e u s u a l l y s e p a r a t e d by " v a l l e y s " c o n s i s t i n g o f r e l a t i v e l y f i n e m a t e r i a l . DIAMICTON - N o n - s o r t e d t o p o o r l y s o r t e d c l a s t i c s e d i m e n t c o n -s i s t i n g o f s and and l a r g e r p a r t i c l e s i n a muddy m a t r i x . A D IAMICTITE i s a l i t h i f i e d d i a m i c t o n . B o t h a r e n o n - g e n e t i c a I Iy d e f i n e d t e r m s ( F l i n t e t a l . , I 9 6 0 ) . EDGE WAVE - A wave f o r m t r a p p e d i n t h e n e a r s h o r e z o n e due t o c o n t i n u a l r e f l e c t i o n o f f t h e f o r e s h o r e , and r e l a t i v e l y r a p i d movement o f i t s deep w a t e r e n d . T h i s r e s u l t s i n t h e wave f o r m r o t a t i n g a b o u t i t s s l o w e r mov ing l a n d w a r d e n d . EQUIL IBR IUM - I. A t r a n s v e r s e p r o f i l e on a b e a c h , w h i c h d e s p i t e m i n o r f l u c t u a t i o n s , m a i n t a i n s i t s f o r m f o r r e l a t i v e l y l ong p e r i o d s o f t i m e . 2. A p l a n i m e t r i c c o a s t a l s h a p e w h i c h m a i n t a i n s c o n s t a n t g e o m e t r i c d i m e n s t i o n s f o r r e l a t i v e l y l ong p e r i o d s o f t i m e . 243. B o t h i and 2 r e p r e s e n t a g e n e r a l s t e a d y s t a t e i n t h e a c t i o n o f waves and c u r r e n t s , and t h e r a t e o f s e d i m e n t movements L ITTORAL CURRENT - A c u r r e n t g e n e r a t e d i n t h e s u r f z o n e by waves b r e a k i n g a t an a n g l e t o t h e s h o r e l i n e . L ITTORAL DRIFT - S e d i m e n t movement a l o n g t h e f o r e s h o r e due t o l i t t o r a l o r l o n g s h o r e c u r r e n t s . LONGSHORE CURRENT - A c u r r e n t g e n e r a t e d i n t h e s h o a l i n g , b r e a k e r and s u r f z o n e s by wave d i v e r g e n c e and d i f f r a c t i o n . WATER TABLE L INE OF EMERGENCE - The l i n e o f i n t e r s e c t i o n b e t w e e n t h e f o r e s h o r e and u p p e r s u r f a c e o f a z o n e o f s a t u r a t i o n . 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0053108/manifest

Comment

Related Items