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Holocene lacustrine sedimentation in a small subalpine watershed in the Coast Mountains of British Columbia Souch, Catherine Jane 1984

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HOLOCENE LACUSTRINE SEDIMENTATION IN A SMALL SUBALPINE WATERSHED IN THE COAST MOUNTAINS OF BRITISH COLUMBIA By CATHERINE JANE SOUCH B.A., U n i v e r s i t y of Cambridge, 1982 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Geography) We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA October 1984 © Catherine Jane Souch, 1984 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e for reference and study. I further agree that permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head of my department or by his or her representatives. I t i s understood'that copying or p u b l i c a t i o n of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department Of Geography  The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date October / /98+ i i ABSTRACT The l a k e sed imen ts o f G a l l i e Pond, a s u b a l p i n e l a k e w h i c h d r a i n s t h e Goat Meadows w a t e r s h e d , a d r a i n a g e b a s i n i n t h e Coast M o u n t a i n s o f s o u t h w e s t e r n B r i t i s h C o l u m b i a , were i n v e s t i g a t e d t o d e t e r m i n e sed iment t r a n s f e r s o p e r a t i n g over t h e Ho locene Epoch. Samples were c o l l e c t e d f rom t h e t e r r e s t r i a l d e p o s i t s o f t h e Goat Meadows w a t e r s h e d and t w e n t y s i x c o r e s were t a k e n f rom t h e l a k e sed imen ts o f G a l l i e Pond. P h y s i c a l , c h e m i c a l and m i n e r a l o g i c a l a n a l y s e s were c o n d u c t e d on the t e r r e s t r i a l and l a k e sed iment samples i n o r d e r t o d e t e r m i n e sed iment d e p t h , s i z e range and v a r i a b i l i t y o f s p e c i f i c p r o p e r t i e s of t he s e d i m e n t s . The r e s u l t s i n d i c a t e t h a t t he Goat Meadows w a t e r s h e d has rema ined a r e l a t i v e l y low energy e r o s i o n a l sys tem over t h e Ho locene Epoch. The 1 i t h o s t r a t i g r a p h y of t h e sed imen ts b e s t r e c o r d s t h e deve lopment o f t h e l a k e f rom i n i t i a l c o n d i t i o n s o f f l o w i n g w a t e r , t o a pea t bog and s u b s e q u e n t l y t o . a n o l i g o t r o -p h i c l a k e ; a t r a n s i t i o n w h i c h may be r e l a t e d t o r e g i o n a l p a l a e o c l i m a t i c change . Sediment y i e l d f rom the w a t e r s h e d over t h e Holocene Epoch has v a r i e d by one o r d e r o f m a g n i t u d e . The mean r a t e i s one and two o r d e r s of magn i tude l ower t h a n t h e c o n t e m p o r a r y d a t a f o r t h e w a t e r s h e d and t h e Coast Moun ta ins r e g i o n r e s p e c t i v e l y . The source a r e a f o r t h e c l a s t i c sed iment w i t h i n t h e w a t e r s h e d ' h a s changed f rom p o o r l y wea the red t i l l t o pedogen ic sou rces w i t h t i m e , w h i l e t h e l a k e ' s o r g a n i c m a t t e r has rema ined p r i m a r i l y a l l o c h t h o n o u s i n o r i g i n . In the context of r e g i o n a l palaeoenvironments t h i s study i n d i c a t e s r a p i d p a r a g l a c i a l e r o s i o n of g l a c i a l sediment i n the immediate p o s t g l a c i a l completed by ca. 10,000 years B.P.; an e a r l y date f o r the h y p s i t h e r m a l - n e o g l a c i a l boundary ca. 6300 years B.P.; p r o g r e s s i v e c o o l i n g of the three post hypsithermal n e o g l a c i a l i n t e r v a l s ; and, i n c r e a s e d a e o l i a n a c t i v i t y over the l a t t e r part of the Holocene Epoch. i v TABLE OF CONTENTS Page ABSTRACT i i LIST OF TABLES v i i i LIST OF FIGURES x ACKNOWLEDGEMENTS x i i CHAPTER 1 INTRODUCTION 1 1.1 Regional context 1 1.2 Conceptual framework and O b j e c t i v e s 4 1.3 Research methodology 5 CHAPTER 2 THE LAKE-WATERSHED APPROACH 8 2.1 I n t r o d u c t i o n 8 2.2 . C a l i b r a t i o n and e x t r a p o l a t i o n of e r o s i o n r a t e s 9 2.2.1 Methodology 10 2.3 I d e n t i f i c a t i o n of sediment source areas 13 2.3.1 Mineralogy 13 2.3.2 M i n e r a l magnetic s t u d i e s 13 2.3.3 C:N r a t i o s 14 2.4 Palaeoenvironmental r e c o n s t r u c t i o n s 14 2.4.1 S t r a t i g r a p h y 15 2.4.2 T e x t u r a l c h a r a c t e r i s t i c s 15 2.4.3. Chemical c h a r a c t e r i s t i c s 16 2.4.4 Organic content 17 2.5 Watershed processes 17 V CHAPTER 3 STUDY AREA 19 3.1 L o c a t i o n 19 3.2 G a l l i e Pond 19 3.3 Climate 26 3.4 Geology 27 3.5 S u r f i c i a l sediments 27 3.6 S o i l s 29 3.7 Ve g e t a t i o n 29 3.8 Late Quaternary h i s t o r y 29 CHAPTER 4 FIELD AND LABORATORY METHODS 34 4.1 Fieldwork 34 4.1.1 Sampling of the lake sediments 34 4.1.2 Sampling of the h i l l s l o p e d e p o s i t s 37 4.2 Laboratory methods 37 4.2.1 P r e p a r a t i o n of f i e l d samples 37 4.2.2 P h y s i c a l a n a l y s e s 40 4.2.2.1 Bulk d e n s i t y , moisture and organic matter content 40 4.2.2.2 P a r t i c l e s i z e a n a l y s i s 40 4.2.3 M i n e r a l o g i c a l analyses 42 4.2.4 Chemical analyses 44 4.2.4.1 Measurement of pH 44 4.2.4.2 D i t h i o n i t e e x t r a c t a b l e i r o n and aluminium 44 4.2.4.3 T o t a l element a n a l y s i s 44 4.2.4.4 Organic carbon and n i t r o g e n 45 v i CHAPTER 5 RESULTS AND DISCUSSION 46 5.1 Temporal and s p a t i a l v a r i a b i l i t y of sedimentary c h a r a c t e r i s t i c s 46 5.1.1 S t r a t i g r a p h y 46 5.1.2 Minerogenic bulk d e n s i t y 51 5.1.3 Organic matter content 55 5.1.4 P a r t i c l e s i z e d i s t r i b u t i o n 58 5.1.5 Mineralogy 73 5.1.6 E x t r a c t a b l e i r o n and aluminium 76 5.1.7 Chemical p r o p e r t i e s of the sediments 78 5.1.8 Organic carbon, n i t r o g e n 83 5.2 Temporal v a r i a b i l i t y i n sediment y i e l d 84 5.2.1 E s t i m a t i o n of r a t e s of accumulation 84 5.2.2 The sampling technique 88 5.2.3 I n t e r p r e t a t i o n of r e s u l t s 90 5.2.4 The source of the sediment 96 5.3 I d e n t i f i c a t i o n of sediment sources 98 5.3.1 M i n e r a l o g i c a l evidence 98 5.4 D i s c u s s i o n 104 5.4.1 10,500 - 6600 years B.P. 104 5.4.2 6600 - 6340 years B.P. 107 5.4.3 6340 - 2400 years B.P. 108 5.4.4 2400 years B.P. to the present 109 5.5 Regional context 110 CHAPTER 6 CONCLUDING COMMENTS 114 REFERENCES CITED 117 APPENDICES v i 1 Appendix I Re p r e s e n t a t i v e s o i l p r o f i l e d e s c r i p t i o n s of the Goat Meadows watershed 127 Appendix II V e g e t a t i o n a s s o c i a t i o n s of the Goat Meadows watershed 131 Appendix III C h r o n o l o g i c a l c o n t r o l 134 Appendix IV L i t h o s t r a t i g r a p h y of the cores 136 Appendix V Lake sediment c h a r a c t e r i s t i c s : p a r t i c l e s i z e and t o t a l element content 143 Appendix VI X.R.D. d i f f r a c t o g r a m s 146 v i i i LIST OF TABLES Table Page 2.1 Core c o r r e l a t i o n methods 12 3.1 Morphometric c h a r a c t e r i s t i c s of G a l l i e Pond 23 3.2 Summary of s o i l and v e g e t a t i o n complexes that c h a r a c t e r i s e the Goat Meadows watershed 31 4.1 Sample s i z e s used i n l a b o r a t o r y analyses 41 4.2 Computational forms of graphic s t a t i s t i c s 43 5.1 Minerogenic bulk d e n s i t i e s by s t r a t i g r a p h i c h o r i z o n 53 5.2 Organic matter content by s t r a t i g r a p h i c h o r i z o n 56 5.3 Summary of p a r t i c l e s i z e c h a r a c t e r i s t i c s by s t r a t i g r a p h i c h o r i z o n 59 5.4 P a r t i c l e s i z e c h a r a c t e r i s t i c s of the s o i l s of the Goat Meadows watershed 71 5.5 R e l a t i v e abundance of c l a y m i n e r a l s i n < 2/LUTI f r a c t i o n i n the s t r a t i g r a p h i c h o r i z o n s of the master core 74 5.6 C o r r e l a t i o n c o e f f i c e n t s f o r each p a i r of elements , 81 5.7 Sedimentation i n G a l l i e Pond 87 5.8 Comparison of d i f f e r e n t methods f o r determining sediment volumes i n G a l l i e Pond 89 5.9 Sediment y i e l d from the Goat Meadows watershed 93 5.10 Contemporary sediment budget f o r the Goat Meadows watershed 94 5.-11 Regional r a t e s of sediment y i e l d 94 5.12 Pe t r o g r a p h i c d e s c r i p t i o n s of l i t h o l o g i e s 100 5.13 R e l a t i v e abundance of c l a y m i n e r a l s i n < 2nm f r a c t i o n s i n the hor i z o n s of r e p r e s e n t a t i v e pedons 101 5.14 R e l a t i v e abundance of m i n e r a l s i n the < 63um ix f r a c t i o n of contemporary l o e s s near Goat Meadows 103 III.1 Radiocarbon dates of Mazama and Bridge River ash d e p o s i t i o n 135 V.1 P a r t i c l e s i z e c h a r a c t e r i s t i c s f o r s e l e c t e d lake sediment samples 143 V.2 T o t a l element content of the s t r a t i g r a p h i c h o r i z o n s of the master core 145 X LIST OF FIGURES Fi g u r e Page 3.1 L o c a t i o n of the study area i n southern B r i t i s h Columbia 20 3.2 The three subcatchments 22 3.3 The Goat Meadows watershed 24 3.4 G a l l i e Pond 25 3.5 The s t r a t i g r a p h y of the s o i l s 28 3.6 S o i l - v e g e t a t i o n complexes of the Goat Meadows watershed 30 4.1 Co r i n g l o c a t i o n s i n G a l l i e Pond 35 4.2 Sampling l o c a t i o n s of the s o i l s i n the Goat Meadows watershed 38 5.1 S t r a t i g r a p h y of the master core 48 5.2 Temporal v a r i a b i l i t y of minerogenic bulk d e n s i t y , organic matter, carbon, n i t r o g e n and C:N r a t i o s down the master core 52 5.3 S p a t i a l v a r i a b i l i t y of minerogenic bulk d e n s i t y in the s u r f a c e sediments of G a l l i e Pond 54 5.4 S p a t i a l v a r i a b i l i t y of the organic matter content of the s u r f a c e sediments of G a l l i e Pond 57 5.5 T e x t u r a l t r i a n g l e 61 5.6 Temporal v a r i a b i l i t y of t e x t u r a l c h a r a c t e r i s t i c s f o r : (a) core C.2 62 (b) core F. 1 63 (c) core 1.1 64 5.7 T e x t u r a l c h a r a c t e r i s t i c s of the s u r f a c e sediments of G a l l i e Pond: (a) Mean s i z e 68 (b) Standard d e v i a t i o n 68 (c) Skewness 69 (d) K u r t o s i s 69 5.8 P l o t s of sediment s i z e : (a) Mean vs. Standard d e v i a t i o n 72 (b) Mean vs. Skewness 72 x i 5.9 E x t r a c t a b l e i r o n and aluminium content of the s t r a t i g r a p h i c u n i t s of the master core 77 5.10 T o t a l element content of the s t r a t i g r a p h i c u n i t s of the master core 79 5.11 Isopach maps of sediment accumulation i n G a l l i e Pond f o r four p e r i o d s : (a) Depth of sediment to top of t i l l 85 (b) Depth to s u r f a c e on which Mazama ash dep o s i t e d 85 (c) Depth to top of peat 86 (d) Depth to s u r f a c e on which Bridge River ash de p o s i t e d 86 x i i ACKNOWLEDGEMENTS I would l i k e to g r a t e f u l l y acknowledge the guidance of my su p e r v i s o r y committee: Dr. 0. Slaymaker f o r h i s encouragement and support throughout the study; Dr. M. Church f o r h i s advice and c o n s t r u c t i v e c r i t i c i s m ; and, Dr. L. L a v k u l i c h f o r a s s i s t a n c e with l a b o r a t o r y procedures. Many people have helped with f i e l d and l a b o r a t o r y work, to these I express my s i n c e r e thanks: P. C a r b i s ; V. Chamberlain; P. Jones; D. Kaye; D. M a r s h a l l ; T. Nguyen; Dr. C. Pharo; Dr. G. Rouse; I. Souch; and E. Wolterson. Most e s p e c i a l l y I would l i k e to thank G. B a r r e t t , T. G a l l i e and S. Grimmond f o r t h e i r a s s i s t a n c e and h e l p f u l d i s c u s s i o n s . T h i s r e s e a r c h was funded by a Canadian Commonwealth S c h o l a r s h i p and a Na t u r a l S c i e n c e s and E n g i n e e r i n g Research C o u n c i l o p e r a t i n g grant to Dr. 0. Slaymaker. 1 CHAPTER 1 INTRODUCTION The aim of t h i s study i s to undertake a lake sediment based i n v e s t i g a t i o n of sediment t r a n s f e r s o p e r a t i n g w i t h i n a subalpine drainage basin i n the Coast Mountains of south west-ern B r i t i s h Columbia over the Holocene Epoch. The r e s u l t s of t h i s i n v e s t i g a t i o n are c o n s i d e r e d i n the context of r e g i o n a l palaeogeomorphic episodes. 1.1 Regional context The landscape of the southern Coast Mountains of B r i t i s h Columbia embodies elements of th r e e d i s t i n c t temporal and s p a t i a l s c a l e s . At the r e g i o n a l l e v e l the mountains, major s t r u c t u r a l lineaments, fragments of e r o s i o n s u r f a c e s and asso-c i a t e d summit l e v e l s are the most e x t e n s i v e landscape f e a t u r e s . These are the product of t e c t o n i c processes and s u b a e r i a l denudation o p e r a t i n g over the T e r t i a r y p e r i o d . They provide the framework upon which more l o c a l i s e d forms have subsequently developed. During the P l e i s t o c e n e Epoch, v a l l e y s and mountain r i d g e s were mo d i f i e d by g l a c i a l p r o c e s s e s . The morphology of the r e s u l t a n t landforms e x h i b i t s some r e g i o n a l v a r i a b i l i t y , with d i s t i n c t i v e f e a t u r e s r e l a t i n g to the aggregate e f f e c t of g l a c i a t i o n s throughout the Quaternary. Over the p o s t g l a c i a l p e r i o d only minor m o d i f i c a t i o n of v a l l e y s has o c c u r r e d through the r e d e p o s i t i o n of g l a c i a l d r i f t by mass wasting and f l u v i a l p r o c e s s e s . The r e s u l t i n g landforms are e n t i r e l y l o c a l i n c h a r a c t e r (Ryder, 1981). P a t t e r n s of p o s t g l a c i a l sedimentation and e r o s i o n have 2 been l i t t l e s t u d i e d (Slaymaker and McPherson, 1977). Those i n v e s t i g a t i o n s that have been undertaken have been concerned p r i m a r i l y with lowland environments and the mountain f r o n t -g l a c i a t e d v a l l e y i n t e r f a c e , with a t t e n t i o n d i r e c t e d towards a l l u v i a l fans and c o l l u v i a l apron d e p o s i t s (Ryder, 1971; F u l t o n , 1975; Ryder, 1978). These s t u d i e s i n d i c a t e that throughout B r i t i s h Columbia a p e r i o d of intense geomorphic a c t i v i t y f o l l o w e d d e g l a c i a t i o n , d u r i n g which e r o s i o n a l and d e p o s i t i o n a l processes were c o n t r o l l e d p r i m a r i l y by the s u s c e p t i b i l i t y of g l a c i a l d r i f t t o r e d i s t r i b u t i o n under n o n - g l a c i a l c o n d i t i o n s . Rapid aggradation o c c u r r e d i n r i v e r v a l l e y s and on lowlands as g l a c i a l sediments w e r e . t r a n s f e r r e d from uplands and v a l l e y s i d e s to be d e p o s i t e d i n fans and d e l t a s on f l o o d p l a i n s , p o s i t i o n s of s t a b i l i t y i n the p o s t g l a c i a l environment (Church and Ryder, 1972). Slopes that had been steepened by g l a c i a l e r o s i o n , and d r i f t covered s l o p e s , were v u l n e r a b l e to f a i l u r e s of v a r i o u s types ranging from major l a n d s l i d e s to s u r f a c e creep (Ryder, 1978). T h i s i n t e r v a l i n which r a p i d n o n g l a c i a l sedimentation was d i r e c t l y c o n d i t i o n e d by g l a c i a t i o n has been termed the p a r a g l a c i a l p e r i o d (Church and Ryder, 1972). As s l o p e s s t a b i l i s e d and v e g e t a t i o n became e s t a b l i s h e d sediment supply to r i v e r s and streams decreased. T h i s i n con-j u n c t i o n with a f a l l i n base l e v e l , a s s o c i a t e d with g l a c i o -i s o s t a t i c u p l i f t , l e d to a t r a n s i t i o n from c o n d i t i o n s of r a p i d p a r a g l a c i a l sediment supply to gradual reworking and removal of 3 these d e p o s i t s . Throughout the southern i n t e r i o r of B r i t i s h Columbia, Mazama ash, d e p o s i t e d 6600 years B.P. (Powers and Wilcox, 1964) occurs c l o s e to the present land s u r f a c e i n t a l u s cones and other c o l l u v i a l d e p o s i t s , i n d i c a t i n g that mass was-t i n g p r o cesses, i n g e n e r a l , were most e f f e c t i v e i n e a r l y p o s t -g l a c i a l time. P a r a g l a c i a l sedimentation i n south c e n t r a l B r i t i s h Columbia was l a r g e l y complete by 8000 years B.P. (Church, p e r s . comm.). A e o l i a n sedimentation, l i k e f l u v i a l aggradation o c c u r r e d p r i m a r i l y d u r i n g the l a t e g l a c i a l and e a r l y p o s t g l a c i a l time ( F u l t o n , 1975). A l l e y (1976) has found that most l o e s s and sand d e p o s i t i o n i n the Okanagan v a l l e y , i n the southern i n t e r i o r of B r i t i s h Columbia, occurred p r i o r to 6600 years B.P., d u r i n g the hypsithermal i n t e r v a l . During d e g l a c i a t i o n a e o l i a n m a t e r i a l was d e r i v e d p r i m a r i l y from unvegetated areas and d e p o s i t e d i n p r o t e c t e d a r e a s . F l u c t u a t i o n s of temperature and p r e c i p i t a t i o n i n the l a t e Holocene Epoch were s u f f i c i e n t to cause the expansions of mountain g l a c i e r s and the onset of n e o g l a c i a l c o n d i t i o n s . These c l i m a t i c f l u c t u a t i o n s have occ u r r e d i r r e g u l a r l y but can be grouped i n t o three main n e o g l a c i a l i n t e r v a l s : 5800 - 4900 years B.P.; 3300 - 2300 years B.P.; and, from 1000 years B.P. to the present (Ryder, 1978). Most g l a c i e r s reached t h e i r maximum p o s t g l a c i a l extent w i t h i n the l a s t two c e n t u r i e s (Mathews, 1951; Ryder et a l . , 1981). In a d d i t i o n to the formation of n e o g l a c i a l moraines such i n t e r v a l s may have l e d to i n c r e a s e d f l u v i a l a c t i v i t y or the renewal of moisture dependent forms of mass 4 movement (Ryder, 1978). Over the Holocene Epoch l o c a l i s e d sediment r e m o b i l i s a t i o n between storage zones has had an important i n f l u e n c e upon the d e t a i l e d geomorphology of many small a l p i n e and sub a l p i n e watersheds, yet l i t t l e i s known of the chronology and importance of such events. For t h i s reason t h i s study was i n i t i a t e d to undertake a s t r a t i g r a p h i c a l l y based i n v e s t i g a t i o n of sediment t r a n s f e r s o p e r a t i n g over the Holocene Epoch. 1.2 Conceptual framework and O b j e c t i v e s The movement of sediment through a watershed may be e n v i -saged as a cascade of matter (Chorley and Kennedy, 1971) with m a t e r i a l moving e p i s o d i c a l l y between temporary storages (Swanson et a l . , 1982). The most comprehensive records of long term geomorphic h i s t o r y are found imprinted on sediments " s t o r e d " i n d e p o s i t i o n a l environments (Church, 1980). However, p r e s e r v a t i o n of such sediment v a r i e s and t e r r e s t r i a l d e p o s i t s are the ones l e a s t l i k e l y to be maintained u n a f f e c t e d , p a r t i c u l a r l y at high e l e v a t i o n s (Hilton-Johnson, 1982). Lakes, with a p p r o p r i a t e geometry and h y d r a u l i c c o n d i t i o n s , may t r a p a h i g h p r o p o r t i o n of i n f l o w i n g p a r t i c u l a t e s from t h e i r surroun-ding catchments, thus p r o v i d i n g o p p o r t u n i t i e s to determine temporal v a r i a b i l i t y of sediment movement i n a catchment, i n terms of both i t s volume and provenance ( O l d f i e l d , 1977, 1981; Jones and Bowser,1978; Dearing, 1982). The primary aim of t h i s study i s to undertake a lake sediment based i n v e s t i g a t i o n of the sediment t r a n s f e r s 5 o p e r a t i n g over the Holocene Epoch w i t h i n a subalpine watershed. T h i s w i l l be achieved through the c h a r a c t e r i s a t i o n of the p o s t g l a c i a l sediments of G a l l i e Pond, a small subalpine lake which d r a i n s the Goat Meadows watershed, a drainage b a s i n w i t h i n the L i l l o o e t R i v e r system i n the eastern Coast Mount-a i n s , near Pemberton, B r i t i s h Columbia. More s p e c i f i c a l l y t h i s w i l l e n t a i l : 1) an assessment of the temporal v a r i a b i l i t y of sedimen-t a r y c h a r a c t e r i s t i c s , and s p a t i a l v a r i a b i l i t y of s e l e c t e d p r o p e r t i e s of the sediments of G a l l i e Pond; 2) an assessment of the temporal v a r i a b i l i t y of sediment y i e l d of the Goat Meadows watershed from the accumulated s e d i -ments i n G a l l i e Pond; 3) an attempt to determine any v a r i a t i o n s i n the dominant source areas of the l a c u s t r i n e d e p o s i t e d c l a s t i c sediment over the p o s t g l a c i a l p e r i o d ; and, 4) r e c o n s t r u c t i o n of the sedimentary environment of the Goat Meadows watershed f o r four time p e r i o d s w i t h i n the Holocene Epoch. The f i n d i n g s of these s p e c i f i c o b j e c t i v e s w i l l be d i s c u s s e d i n the context of r e g i o n a l palaeogeomorphic episodes. 1 . 3 Research methodology The Goat Meadows watershed was s e l e c t e d f o r study as pa r t of ongoing r e s e a r c h i n t o the c l a s t i c sediment y i e l d of the L i l l o o e t R i v e r system (Slaymaker and G i l b e r t , 1972; G i l b e r t , 1973; Slaymaker, 1977; Hart, 1979; Jones, 1982). 6 The f i e l d w o r k f o r t h i s i n v e s t i g a t i o n was conducted d u r i n g the summer of 1983. G a l l i e Pond was s e l e c t e d f o r d e t a i l e d study a f t e r a p r e l i m i n a r y i n v e s t i g a t i o n of three l a k e s i n the v i c i n i t y of the Goat Meadows watershed: Ash Lake, Middle Lake and G a l l i e Pond, r e v e a l e d d i s c o n t i n u i t i e s i n the sedimentary records of the f i r s t two. Samples were c o l l e c t e d from the t e r r e s t r i a l d e p o s i t s of the Goat Meadows watershed, and twenty s i x cores were taken from the lake sediments i n G a l l i e Pond using a systematic sampling s t r a t e g y . P h y s i c a l , chemical and mineralo-g i c a n a l y s e s were conducted on the t e r r e s t r i a l and lake s e d i -ment samples. The r a t i o n a l e f o r the p a r t i c u l a r c h o ice of prop-e r t i e s , based on the r e s u l t s and recommendations of pre v i o u s r e s e a r c h , i s presented i n Chapter 2. L o g i s t i c a l c o n s t r a i n t s l e d to many of the more d e t a i l e d a n a l y ses being conducted on a l i m i t e d number of lake sediment and s o i l samples. Using the c r i t e r i a of g r e a t e s t accumulation and r e p r e s e n t a t i v e n e s s of a l l the s t r a t i g r a p h i c u n i t s present a master core was s e l e c t e d on which these analyses were conducted and a g a i n s t which a l l other cores were c r o s s - c o r r e l a t e d . A number of the analyses were conducted on s e v e r a l cores i n order to assess the r e p r e s e n t a t i -veness of the r e s u l t s of the master c o r e , and to o b t a i n some i n d i c a t i o n of s p a t i a l v a r i a b i l i t y i n sedimentary c h a r a c t e r i s t -i c s . The r e s u l t s of the analyses are i n t e r p r e t e d i n the context of temporal v a r i a b i l i t y i n sedimentary c h a r a c t e r i s t i c s , sedim-ent y i e l d and sediment source areas, and subsequently i n t e g -r a t e d to pr o v i d e i n s i g h t i n t o sediment t r a n s f e r s , sources and s i n k s o p e r a t i n g i n the Goat Meadows watershed over the 7 Holocene Epoch. The f i n a l s e c t i o n of Chapter 5 provides some d i s c u s s i o n of the c o n s i s t e n c y of these r e s u l t s with r e g i o n a l palaeoenvironmental h i s t o r y and an assessment of the approach i n the r e c o n s t r u c t i o n of sedimentary environments. 8 CHAPTER 2 THE LAKE-WATERSHED APPROACH 2.1 I n t r o d u c t i o n The lake-watershed approach may be envisaged as a m o d i f i c a t i o n of the sediment cascade i n which lakes are viewed as the primary sediment s i n k s i n a drainage b a s i n , the sediments co n t a i n e d i n which provide the most comprehensive r e c o r d of long term geomorphic h i s t o r y ( s e c t i o n 1.2). Sediment accumulation i n a lake i s a consequence of the net balance between input and l o s s through the outflow ( i . e . t r a p e f f i c i e n c y ) , which may be r e l a t e d to sediment type, water d e t e n t i o n time and lake morphometry ( O l d f i e l d , 1977). Inputs i n t o a lake c o n s i s t of org a n i c and i n o r g a n i c sediments that p o t e n t i a l l y are d e r i v e d from a number of sources. The sediments are a f u n c t i o n of the complex i n t e r a c t i o n s between mechanisms of d e p o s i t i o n , resuspension, chemical and bi o g e n i c t r a n s f o r m a t i o n s , exchange with water and organisms, and longer term d i a g e n e s i s (Dearing, 1982). T h i s chapter w i l l present a review of s e l e c t e d s t u d i e s of lake sediments conducted w i t h i n the lake-watershed framework which have p r o v i d e d i n s i g h t i n t o geomorphological processes that occur over a range of t i m e s c a l e s (10 1 — 10 5 y e a r s ) , i n order to introduce the r a t i o n a l e behind the techniques and methodologies used i n t h i s study. T h i s study i s concerned p r i m a r i l y with the c l a s t i c and chemical components of lake sediments. T h e r e f o r e t h i s review w i l l not c o n s i d e r the a d d i t i o n a l i n f o r m a t i o n that may be obtained from p a l y n o l o g i c a l , m a c r o f o s s i l or diatom analyses (as 9 reviewed by Berglund, 1979). For ease of d i s c u s s i o n the s t u d i e s reviewed w i l l be su b d i v i d e d by o b j e c t i v e , to p a r a l l e l three of the more s p e c i f i c o b j e c t i v e s of t h i s study ( s e c t i o n 1.3), i n t o those concerned with: 1) the c a l i b r a t i o n and e x t r a p o l a t i o n of e r o s i o n r a t e s ; 2) the i d e n t i f i c a t i o n of sediment source areas; and, 3) palaeogeomorphic r e c o n s t r u c t i o n s . 2.2 C a l i b r a t i o n and e x t r a p o l a t i o n of e r o s i o n r a t e s H i l l s l o p e processes are o f t e n slow and h i g h l y v a r i a b l e i n both space and time. T h i s i n e v i t a b l y leads to many problems a s s o c i a t e d with s c a l e and sampling procedures when attempts are made to monitor " r e p r e s e n t a t i v e " process r a t e s (Meade, 1969; Bovis, 1982). Recent rese a r c h has suggested that i n f l u x data from t o t a l sediment volumes i n lake b a s i n s may pro v i d e a crude b a s i s f o r determining or e x t r a p o l a t i n g contemporary sediment y i e l d data t o longer time i n t e r v a l s (Bloemandal et a l . , 1979; Dearing et a l . , 1981; Dearing et a l . , 1982). However, few attempts have yet been made to lengthen the temporal r e f e r e n c e s c a l e or to improve the r e s o l u t i o n of c a l c u l a t e d process r a t e s . In the context of such s t u d i e s c h r o n o l o g i e s , which are used not only f o r d a t i n g events, but a l s o c a l c u l a t i n g r a t e s of m a t e r i a l f l u x , are commonly p r o v i d e d by methods i n c l u d i n g : radiocarbon d a t i n g ; tephra l a y e r s ; annual laminae/varves; l e a d -210; and, caesium-137 ( f o r a review see O l d f i e l d , 1977, 1981). The p o t e n t i a l of lake sediments i n extending contemporary 10 o b s e r v a t i o n s i s at present l i m i t e d to s t u d i e s of p a r t i c u l a t e f l u x . Most s o l u t e s are l o s t from the catchment, they w i l l not s e t t l e out as most p a r t i c u l a t e s w i l l do. Hence the o b s e r v a t i o n s of s o l u t e f l u x e s through n u t r i e n t analyses are u n l i k e l y to be at a r e s o l u t i o n f i n e r than gross changes in n u t r i e n t loadings that accompany major environmental change (see s e c t i o n 2.2.3). 2.2.1 Methodology The idea of using a long continuous r e c o r d of d e p o s i t i o n i s not new (see review by Matter and Tucker, 1978). T o t a l sediment volumes have been estimated f o r r e s e r v o i r s (Rapp et a l . , 1972; Dendy et a l , 1973) by comparing p e r i o d i c measurements of water depth with o r i g i n a l basin form, and i n l a k e s , using e i t h e r s e i s m i c r e f l e c t i o n p r o f i l e s (Bruland et a l . , 1975) or the advance of d e l t a s ( G i l b e r t , 1973). However, where s t u d i e s r e q u i r e i n f o r m a t i o n on temporal v a r i a t i o n s i n e r o s i o n r a t e s , over p e r i o d s 10 1 — 1 0 5 y e a r s , such techniques are f r e q u e n t l y i n a p p r o p r i a t e , and c a l c u l a t i o n s are more a p p r o p r i a t e l y based on sediment t h i c k n e s s e s found between d i s t i n c t s t r a t i g r a p h i c or dated h o r i z o n s i n a sediment c o r e . Observed v a r i a b i l i t y in i n f l u x r a t e s at d i f f e r e n t stages of a l a k e ' s h i s t o r y are then e x p l a i n e d i n terms of a n t h r o p o g e n i c a l l y or e n v i r o n m e n t a l l y induced changes i n a watershed (Davis, 1976; Dearing, 1982; Dearing et a l . , 1982; O ' S u l l i v a n et a l . , 1982). The m a j o r i t y of s t u d i e s of lake sediment d e p o s i t i o n have been based on a s i n g l e core from the deepest p a r t of the l a k e , 11 making assumptions about " f o c u s i n g " of sediment to t h i s p o i n t (Likens and Davis, 1975; Davis, 1976; Edwards and Rowntree, 1980). However, sedimentation p a t t e r n s , e s p e c i a l l y i n small l a k e s , are i r r e g u l a r and may vary through time, thus imposing severe l i m i t a t i o n s on the amount of q u a n t i t a t i v e i n f o r m a t i o n that may be obtained from s i n g l e core records even when time-depth r e l a t i o n s h i p s are s a t i s f a c t o r i l y d e f i n e d . Recent s t u d i e s of s p a t i a l v a r i a t i o n s i n sediment accumulation (Bloemandal et a l . , 1979; Dearing et a l . , 1981; Dearing, 1983) do not support the u n i v e r s a l a p p l i c a t i o n of the concept of "sediment foc u s -i n g " , and thus c r i t i c i s e s t u d i e s that e x t r a p o l a t e sedimentation r a t e s from a s i n g l e core as advocated by Lehman (1975), suggesting that sediment volumes should be estimated from mean sediment t h i c k n e s s e s found i n many cores (Dearing, 1982). Cores are c r o s s - c o r r e l a t e d u s i n g sediment c h a r a c t e r i s t i c s that f u l f i l the c r i t e r i a of a r e a l c o n t i n u i t y and s y n c h r o n e i t y , that i s , the p r o p e r t y of i n t e r e s t i s d e p o s i t e d i n s i m i l a r p r o p o r t i o n s to other c o n s t i t u e n t s over the lake and once d e p o s i t e d i s immobile. The c h a r a c t e r i s t i c s which are commonly used, with comments on t h e i r r e l a t i v e advantages and disadvantages, are summarised i n Table 2.1. Problems of d i s c o n t i n u i t i e s are l i k e l y to be encoun-t e r e d as a consequence of b i o t u r b a t i o n , slumping, d i a g e n e s i s and r e s u s p e n s i o n / d e p o s i t i o n c y c l e s (Dearing, 1983). The need f o r independent s e t s of a n a l y s e s to c o r r o b o r a t e core c o r r e l a t -ions focuses a t t e n t i o n on l o s s on i g n i t i o n , s t r a t i g r a p h y and magnetic a n a l y s e s which are r a p i d , economical and n o n d e s t r u c t i v e 1 2 Table 2.1 Core c o r r e l a t i o n methods Method Comments Examples of s t u d i e s i n which used V i s i b l e s t r a t i g r a p h y  Regular Laminations I r r e g u l a r Sediment c o l o u r / t e x t u r e Most a c c u r a t e ; r e s t r i c t e d o ccurrence. B i o t u r b a t i o n & turbulence may d e s t r o y c o n t i n u i t y . Flat-bottomed lakes i n c o n t i n e n t a l / g l a c -i a t e d areas g r e a t e s t p o t e n t i a l . Problems duri n g e x t r u s i o n / c o r i n g ; smearing may make cores d i f f i c u l t to c r o s s -c o r r e l a t e . S p a t i a l v a r i a t i o n s in a l l o c h t h o n o u s input or chemical c o n d i t i o n s may r e s u l t in d i s c o n t i n u i t i e s . Renberg & (1981) Simola et a l . Segerstrom (1981 ) D i g e r f e l d t et a l . ( l 9 7 5 ) Tephra Good e s p e c i a l l y i n l a r g e l a k e s . Problems i f f o c u s i n g of sediment duri n g d e p o s i t i o n , or from secondary sources. O l d f i e l d et a l . (1980) Other s t r a t i g r a p h i e s : M i c r o f o s s i l R e l i e s on i d e n t i f i c a t i o n of O ' S u l l i v a n et a l . (1973) p o l l e n -diatom Chemical/ Organic matter assemblage boundaries. Time consuming and poor temporal r e s o l u t i o n . Magnetic p r o p e r t i e s S p a t i a l v a r i a t i o n s i n redox p o t e n t i a l and pH c o n d i t i o n s may a f f e c t p a r a l l e l i s m of chemical and O.M. p r o f i l e s . Loss on i g n i t i o n (as surrogate f o r O.M. content) r a p i d , easy to perform & cheap. A l l measurements cheap,rapid & n o n - d e s t r u c t i v e , c a n be done on unextruded c o r e s . Problems i f synchronous l a y e r s charac-t e r i s e d by d i f f e r e n t p a r t i c l e s i z e d i s t r i b u t i o n s , hence problems i f comparing cores i n the l i t t o r a l zone or i n small shallow l a k e s . B o r t l e s o n & Lee (1975) Bloemandal et a l O l d f i e l d (1981) Dearing (1983) (1979) 13 of the c l a s t i c component of the sample. The major problems that s t i l l remain are those of s t r a t i g r a p h i c completeness (Ager, 1973; T i p p e r , 1983), and poor temporal r e s o l u t i o n ( O l d f i e l d et a l . , 1983b). For example, w e l l w i t h i n the upper l i m i t of the temporal r e f e r e n c e frame of t h i s d i s c u s s i o n (10 5 y e a r s ) , changing t r a p e f f i c e n c y , as a consequence of the lake f i l l i n g up, may i t s e l f become a very important e f f e c t on the c h a r a c t e r of the sedimentary r e c o r d . 2.3 I d e n t i f i c a t i o n of sediment source areas Catchment s c a l e e r o s i o n s t u d i e s from lake sediment records tend to report e r o s i o n values averaged f o r the e n t i r e b a s i n . F r e q u e n t l y more s p e c i f i c data on sediment sources are r e q u i r e d . 2.3.1 Mineralogy Rock and mineral provenance s t u d i e s are u s e f u l techniques i n i d e n t i f y i n g source areas of sediments (Jones and Bowser, 1978). T h i s i n c l u d e s d i f f e r e n t i a t i o n of a l l o g e n i c and autogenic o sources, and between t e r r e s t r i a l sources. These i n v e s t i g a t i o n s tend to be h i g h l y q u a l i t a t i v e , although c l a y s i z e d p a r t i c l e mineralogy has proved to be a v a l u a b l e p r o p e r t y f o r d i s t i n g u i s h i n g between a e o l i a n , t e r r e s t r i a l and l i m n o l o g i c sources ( B i r k e l a n d and Andrews, 1982). 2.3.2 M i n e r a l magnetic s t u d i e s S t u d i e s of the m i n e r a l magnetic p r o p e r t i e s of lake sediments ( f o r example, s a t u r a t e d isothermal remanent magnetism 14 and s u s c e p t i b i l i t y ) now c o n t r i b u t e s i g n i f i c a n t l y to the t r a c i n g of sediment sources (Dearing and Flower, 1982; O l d f i e l d et a l . , 1983 a,b). However, the u t i l i t y of these depends upon the nature of the l i t h o l o g y on which the catchment has formed, and the e x i s t e n c e of strong magnetic c o n t r a s t s ( O l d f i e l d , 1981). 2.3.3 C/N r a t i o s B i r k e l a n d and Andrews (1982) have proposed that sediment sources p o t e n t i a l l y may be p i n p o i n t e d through the measurement of C/N r a t i o s (organic c a r b o n : n i t r o g e n content) of lake sediments and the surrounding s u r f a c e (Ah) h o r i z o n s of s o i l s . However, t h i s p r o p o s a l does not take i n t o account the i n f l u e n c e of organic p r o d u c t i o n w i t h i n the lake by a q u a t i c b i o t a , and remains u n s u b s t a n t i a t e d i n the f i e l d . 2.4 Palaeogeomorphic r e c o n s t r u c t i o n s Many r e s e a r c h e r s have c h a r a c t e r i s e d l a c u s t r i n e sediments with the aim of i n t e r p r e t i n g palaeoenvironmental c o n d i t i o n s from f l u c t u a t i o n s in t h e i r sedimentary c h a r a c t e r i s t i c s . The b a s i c r a t i o n a l e u n d e r l y i n g these s t u d i e s i s o u t l i n e d by Frey (1969) and by O l d f i e l d (1977). These r e c o n s t r u c t i o n s are the most complex and i n f e r e n t i a l of the t o p i c s d i s c u s s e d i n t h i s c hapter. Such r e c o n s t r u c t i o n s best r e l y on the f i n d i n g s of r a t e s and sources, so as not to o v e r - i n t e r p r e t change. T h i s s e c t i o n w i l l be concerned p r i m a r i l y with the i n t e r p r e t a t i o n of the d i f f e r e n t sedimentary c h a r a c t e r i s t i c s used r a t h e r than with the o v e r a l l o b j e c t i v e s of the i n v e s t i g a t i o n s . 1 5 2.4.1 S t r a t i g r a p h y Lake sediment s t r a t i g r a p h y has on many occasions been i n t e r p r e t e d on the assumption of a d i r e c t l i n k a g e between c l i m a t i c change and morphogenesis (Andrews et a l . , 1975; Davis et a l . , 1979; S o h l , 1983). For example, minerogenic sediments a s s o c i a t e d with e i t h e r d i r e c t g l a c i a l outwash or p e r i g l a c i a l c o n d i t i o n s and s o l i f l u c t i o n w i t h i n a drainage b a s i n , o f t e n a l t e r n a t e with more organic sediments r e p r e s e n t i n g p e r i o d s of r e l a t i v e warmth d u r i n g which s o i l development took p l a c e and the l a n d s u r f a c e became r e l a t i v e l y s t a b l e , as documented by M a l a u r i e et a l . (1972) in Greenland. A l t e r n a t i v e l y , s t r a t i g r a p h y may r e f l e c t changes i n water l e v e l , f o r example, Andrews et a l . (1975) have documented such f l u c t u a t i o n s over the Holocene time p e r i o d f o r the Front Range of Colorado, from the a l t e r n a t i o n s of peats and i n o r g a n i c s i l t s i n lake sediment c o r e s . 2.4.2 T e x t u r a l c h a r a c t e r i s t i c s T e x t u r a l parameters are c h i e f l y r e l a t e d to the mode of d e p o s i t i o n and the energy c o n d i t i o n s of the t r a n s p o r t i n g medium (Friedman, 1962). The a b i l i t y to i d e n t i f y and d e s c r i b e d e p o s i t i o n a l processes and/or s e d i m e n t o l o g i c a l environments from the t e x t u r a l c h a r a c t e r i s t i c s of a sediment has been the sub j e c t of much co n t r o v e r s y , see f o r example: Shepherd and Young (1961); Schlee et a l . , (1964); Gees (1965); compared with Folk and Ward (1957); Mason and Folk (1958); Friedman (1962); Moiola and Weiser (1968); and V i s h e r (1969). V a r i a t i o n s i n the t e x t u r a l p r o p e r t i e s of lake sediments, 1 6 whether g r a i n s i z e , i n d i c e s of s o r t i n g , the n o r m a l i t y of the d i s t r i b u t i o n or r a t i o s of d i f f e r e n t s i z e c l a s s e s , have been a t t r i b u t e d to a number of f a c t o r s : the source of the m a t e r i a l , so that the lake sediments d i r e c t l y r e f l e c t the nature of the s o i l s i n the catchment and t h e i r degree of weathering (Ostrem, 1975; Edwards and Rowntree, 1980); the e r o s i v e c a p a c i t y of the t r a n s p o r t i n g medium (Thomas et a l . , 1973); d i f f e r e n c e s i n d e p o s i t i o n a l environments and c i r c u l a t i o n p a t t e r n s i n l a k e s (Sly et a l . , 1982); and the impact of anthropogenic e f f e c t s and landuse changes (Warwick, 1980; B i n f o r d , 1983). T e x t u r a l i n f o r -mation i s most i n f o r m a t i v e when combined with other c h a r a c t e r i -s t i c s such as sedimentary s t r u c t u r e s and the morphology of d e p o s i t s . 2.4.3 Chemical c h a r a c t e r i s t i c s V a r i a t i o n s i n the inputs of c a t i o n s such as sodium, potassium and magnesium i n t o lake sediments have been i n t e r p r e t e d as i n d i c a t o r s of changes i n e r o s i o n a l a c t i v i t y w i t h i n a lake catchment (Mackereth, 1965, 1966; Pennington et a l . , 1972; Edwards and Rowntree, 1980). These elements are e a s i l y leached from s u b s t r a t e s , thus i t i s o f t e n i n f e r r e d that t h e i r presence i n the lake sediments i s a f u n c t i o n of the d e t r i t a l input of unweathered m a t e r i a l from which the elements had not p r e v i o u s l y been removed ( O l d f i e l d , 1981). However, the chemical composition of the lake sediment i s a f u n c t i o n of a number of f a c t o r s i n c l u d i n g : chemistry of the input water; source area of the sediment; degree of chemical weathering; and, 1 7 the balance of c l a s t i c and s o l u t e f l u x e s o p e r a t i n g on a h i l l s l o p e . For example, the input of a lake sediment with high adsorbed element content may be a consequence of more h i g h l y weathered m a t e r i a l , l e s s s o l u t e l o s s e s or a new source area. Thus the chemical r e c o r d i n lake sediments, n e g l e c t i n g any i n f l u e n c e of autogenic or endogenic processes, may be a complex response of e r o s i o n a l , pedogenic and h y d r o l o g i c a l regimes. M o d i f i c a t i o n of t h i s i n t e r p r e t a t i o n i s necessary i n lakes l e s s dominated by p h y s i c a l e r o s i o n e s p e c i a l l y where e u t r o p h i c a t i o n has a c c e l e r a t e d a q u a t i c p r o d u c t i v i t y . 2.4.4 Organic content Other c h a r a c t e r i s t i c s commonly used i n palaeoenvironmental r e c o n s t r u c t i o n s i n c l u d e organic matter, carbon and n i t r o g e n c o n t e n t s , which may be used to d i f f e r e n t i a t e autochthonous and a l l o c h t h o n o u s organic matter. In o l i g o t r o p h i c l a k e s , with p r i m a r i l y a l l o c h t h o n o u s input o r g a n i c carbon: n i t r o g e n r a t i o s may be used to i n f e r something of the s t a t u s of the s u r f a c e organic (Ah) h o r i z o n s of the watershed's s o i l s ( D i g e r f e l d t , 1972; B i r k e l a n d and Andrews, 1982). 2.5 Watershed processes The lake-watershed approach i s one example of a g e n e r a l methodology i n geomorphology, namely the open systems frame-work, in which the aim i s to monitor/model i n p u t s , throughputs and outputs of a system. In geomorphology t h i s approach, i n terms of the movement of sediment, has taken many forms, f o r 18 example, Rapp's (i960) e m p i r i c a l work in Karkevagge; K i r k b y ' s (1971, 1978) h i l l s l o p e m o delling based on the c o n t i n u i t y equation; and sediment budgeting, advocated by Swanson et a l . (1982) which attempts to i n t e g r a t e both the e m p i r i c a l and the t h e o r e t i c a l work. The lake-watershed approach p r o v i d e s probably the best c o n t r o l of system outputs and the g r e a t e s t p o t e n t i a l i n s i g h t i n t o palaeogeomorphic p r o c e s s e s . Although many s t u d i e s have been conducted w i t h i n the framework, whether to understand the e v o l u t i o n of drainage b a s i n s ; temporal v a r i a b i l i t y i n sediment sources; or to assess man's i n f l u e n c e on a watershed, there have been few attempts to i n t e g r a t e these r e s u l t s to provide the continuum of i n s i g h t and understanding of sediment movement w i t h i n a watershed which i s p o t e n t i a l l y p o s s i b l e from t h i s approach. I t i s the aim of the study to undertake such an i n v e s t i g a t i o n i n order to determine p o s t g l a c i a l sediment move-ment in a sma l l subalpine drainage b a s i n of the Coast Mountains of B r i t i s h Columbia. 19 CHAPTER 3 STUDY AREA 3.1 L o c a t i o n The Goat Meadows watershed i s a 0.024 km2, f i r s t order catchment which d r a i n s i n t o G a l l i e Pond, a small subalpine l a k e . The watershed i s s i t u a t e d approximately 120 km north of Vancouver, south western B r i t i s h Columbia, i n the P a c i f i c Ranges of the Coast Mountains (Figure 3.1). I t l i e s between 1800 and 1900 m a . s . l . , at the c r e s t of a north f a c i n g r i d g e , which runs p a r a l l e l between L i l l o o e t R i v e r and M i l l e r Creek (Figure 3.1). I t i s the uppermost of three subcatchments which c o n s t i t u t e an unnamed 2 km2 subalpine drainage b a s i n , which d r a i n s i n t o Ryan Ri v e r (Figure 3.1). 3.2 G a l l i e Pond A small unnamed l a k e , which w i l l be r e f e r r e d to as G a l l i e Pond, was s e l e c t e d f o r d e t a i l e d study a f t e r a p r e l i m i n a r y i n v e s t i g a t i o n of the three lakes i n the unnamed catchment (F i g u r e 3.2) re v e a l e d d i s c o n t i n u i t i e s i n the sedimentary r e c o r d of the lower two l a k e s . G a l l i e Pond i s a small o l i g o t r o p h i c lake (Table 3.1), the o u t l e t of which d e f i n e s the lower l i m i t of the Goat Meadows watershed. The lake i s fed by two streams, Hummingbird and Mosquito (Figure 3.3). Losses occur through an ephemeral o u t l e t stream on the north west margin of the l a k e , and groundwater drainage through the pond sediments ( G a l l i e , 1983). G a l l i e Pond i s a shallow l a k e , with a maximum depth d u r i n g the summer of 1983 of 1.26 m ( F i g u r e 3.4). The lake can be 20 F i g u r e 3.1 L o c a t i o n o f the s t u d y a r e a i n s o u t h e r n B r i t i s h Columbia (adapted from B a r r e t t , 1981; G a l l i e , 1983) 23 Table 3.1 Morphometric c h a r a c t e r i s t i c s of G a l l i e Pond G a l l i e Pond S i t e 50°24'N 123°57'W A l t i t u d e (approx.) 1850 m a . s . l . Maximum len g t h 54 m Maximum width 21 m Maximum water depth 1 .26 m Mean water depth 0.61 m Water volume 481 m3 N.B. Data r e f e r to the o u t l e t f l o o r l e v e l of the lake 2 4 F i g u r e 3.3 The Goat Meadows watershed (adapted from G a l l i e , 1983) N N.B. A r b i t r a r y base l e v e l a t o u t l e t t o l a k e 25 b) 26 s u b d i v i d e d i n t o two environments: a deeper c e n t r a l p o r t i o n u n d e r l a i n by f i n e l a c u s t r i n e s i l t s ; and, around the edge a " t i l l s h e l f " , a s i l l covered by a coarse boulder d e p o s i t . The o r i g i n of t h i s f e a t u r e i s u n c e r t a i n , but i t may p o s s i b l y have been formed through the a c t i o n of s u r f a c e i c e , and p e r i o d i c changes in water l e v e l . G a l l i e Pond i s c o n s t r a i n e d at i t s o u t l e t by a rock s i l l which has prevented s c o u r i n g and e r o s i o n of i t s sediments. The in f l o w to volume r a t i o of G a l l i e Pond i s s m a l l , t h e r e f o r e i t i s assumed that i t has operated as a sediment t r a p with g r e a t e r than 95% t r a p e f f i c i e n c y with r e s p e c t to the sand and s i l t s i z e sediments. 3.3 Climate The present mesoscale c l i m a t e may be d e s c r i b e d as c o l d , perhumid. Annual p r e c i p i t a t i o n exceeds 1600 mm ( G a l l i e and Slaymaker, 1983) most of which f a l l s d u r i n g the winter as snow. T e n q u i l l e Lake snowcourse which i s at a s i m i l a r e l e v a t i o n (1640 m) to that of the of Goat Meadows has an average May 1 snowpack of 1250 mm water e q u i v a l e n t (based on 26 years of record) (B.C. M i n i s t r y of Environment, 1984), however, because i t i s 15 km no r t h east of the re s e a r c h s i t e ( F i g u r e 3.1), snow accumulation i s s i g n i f i c a n t l y l e s s than at the study s i t e . Continuous snow cover at the re s e a r c h s i t e p e r s i s t s f o r seven to nine months of the year. In "the summer of 1983, when fiel d w o r k f o r t h i s study was conducted, snow remained i n some of the topographic hollows throughout the e n t i r e year. Ice c o v e r i n g the la k e s i n 1983 d i d 27 not melt completely u n t i l mid August, and began to reform by the end of September. 3.4 Geology The l o c a l bedrock i s ( i ) an a s s o c i a t i o n of metasediments, which were mapped by Woodsworth (1977) as l a t e Cretaceous Gambier group, and ( i i ) q uartz d i o r i t e which belongs to the Coast P l u t o n i c Complex (Roddick, 1976). The dominant l i t h o l o g y i s a q u a r t z - a c t i n o l i t e - c h l o r i t e s c h i s t , which covers approxima-t e l y 70% of the b a s i n ( G a l l i e , 1983), with quartz d i o r i t e outcropping along the north west boundary of the catchment. 3.5 S u r f i c i a l sediments The watershed i s covered by a d i o r i t i c stoney P l e i s t o c e n e t i l l , which i s o v e r l a i n by a number of f i n e t e x t u r e d Holocene d e p o s i t s , i n c l u d i n g two ash l a y e r s : the lower, Mazama (6600 years B.P.); the upper, Bridge R i v e r (2400 B.P.) (see Appendix I I I ) . The two tephra l a y e r s are d i s c o n t i n u o u s and are concen-t r a t e d i n l o c a l sediment t r a p s . The Bridge River ash i s more a r e a l l y e x t e n s i v e than the Mazama, and i s l e s s weathered and c o a r s e r . V a r i a b l e amounts (0.1-0.3 m) of f i n e t e x t u r e d organic r i c h l o e s s d e p o s i t s separate the s u r f a c e o r g a n i c , ash and t i l l l a y e r s (Figure 3.5). Colluvium o v e r l i e s the b a s a l t i l l i n a c t i v e s i t e s . Along the north west margin of the catchment t a l u s has accumulated beneath g l a c i a l l y oversteepened c l i f f s . 28 gure 3.5 The stratigraphy of the s o i l s of the Goat Meadows watershed (adapted from Barrett, 1981) jpper ash -oess loess lower ash loess ablation __ t i l _ l _ _ _ Jlodgement J 1 t i l l 1 loess upper ash loess ablation t i l l , lodgement i t i l l ' o o 3 29 3.6 S o i l s The s o i l s w i t h i n the watershed are a r e a l l y dominated by a c i d i c B r u n i s o l s and Cumulic Regosols, although the pedons present range from Ferro-Humic Podsols, beneath w e l l d r a i n e d t r e e i s l a n d s , to Rego G l e y s o l s i n p o o r l y d r a i n e d s i t e s i n the v i c i n i t y of G a l l i e Pond (F i g u r e 3.6). R e p r e s e n t a t i v e pedons of each s o i l order are d e s c r i b e d and c l a s s i f i e d i n Appendix I a c c o r d i n g to the Canadian system of c l a s s i f i c a t i o n (Canada S o i l Survey Committee, 1978). Furt h e r r e f e r e n c e i s made to the sampling and the s p e c i f i c c h a r a c t e r i s t i c s of these s o i l s i n Chapters 4 and 5. 3.7 V e g e t a t i o n The watershed i s l o c a t e d near the upper a l t i t u d i n a l l i m i t of the l o c a l a l p i n e - s u b a l p i n e ecotone, and i s c h a r a c t e r i s e d by d i s c o n t i n u o u s t r e e i s l a n d s which grade i n t o krummholz l i f e forms. G a l l i e (1983) has i d e n t i f i e d f i v e v e g e t a t i o n a s s o c i a -t i o n s i n the watershed, the s p e c i e s compositions of which are presented i n Appendix I I . T h e i r d i s t r i b u t i o n i s heterogeneous, although s t r o n g c o v a r i a n c e e x i s t s between s u r f i c i a l m a t e r i a l s , s o i l groups and v e g e t a t i o n a s s o c i a t i o n s . Contiguous s o i l -v e g e t a t i o n complexes are mapped i n F i g u r e 3.8 and d e s c r i b e d b r i e f l y i n Table 3.2. 3.8 Late Quaternary h i s t o r y Aspects of the l a t e Quaternary h i s t o r y of the Goat Meadows watershed are being r e c o n s t r u c t e d by Dr. G.E. Rouse, Dr. R.M. 30 F i g u r e 3.6 S o i l - v e g e t a t i o n complexes o f the Goat Meadows watershed (adapted from G a l l i e , 1983) 31 Table 3.2 Summary of s o i l and v e g e t a t i o n complexes that c h a r a c t e r i s e the Goat Meadows watershed (from G a l l i e , 1983) S o i l v e g e t a t i o n % area complex V e g e t a t i o n communities S o i l groups A c t i v e d e b r i s s l o p e s Heath communities 33 Tolmia, S a x i f r a g a Cassiope moss 30 Heath, Heather Sedge-Forb Regosols,Cumulic Regosols and D y s t r i c B r u n i s o l s O r t h i c D y s t r i c B r u n i s o l s and Sombric B r u n i s o l s Bedrock Dwarf sedge 16 E p i p e t r i c l i c h e n s 12 Dwarf sedge, Luetkea-moss-Li c h e n O r t h i c Sombric and D y s t r i c B r u n i s o l s Pond Wetland sedge 4 3 Sedge-Forb-moss, Sedge-Sphagnum Humic Rego G l e y s o l Tree i s l a n d 2 Tree i s l a n d s Humo F e r r i c Podsols 32 B u s t i n and Dr. T.M. G a l l i e of The U n i v e r s i t y of B r i t i s h Columbia. The r e c o n s t r u c t i o n i s based on s t r a t i g r a p h i c and p a l y n o l o g i c a l a n a l y s i s of lake cores e x t r a c t e d from G a l l i e Pond. Temporal c o n t r o l i s provided by f i v e radiocarbon dates and two v o l c a n i c ash d e p o s i t s , Mazama and Bridge River ( G a l l i e , 1983) (Appendix I I I ) . The study r e p r e s e n t s the f i r s t of a high e l e v a t i o n palynomorph assemblage in the north west Washington -south west B r i t i s h Columbia r e g i o n . Remarkable s i m i l a r i t i e s to the lowland p r o f i l e s of Mathewes (1973), Mathewes and Rouse (1975), Heusser et a l . , 1980, Barnosky (1981), and Mathewes and Heusser (1981) are evident (Rouse, p e r s . comm.). A b a s a l date on the lake sediments i n d i c a t e s that d e g l a c -i a t i o n o c c u r r e d p r i o r to 10,500 +500 years B.P. T h i s i s i n accordance with other dates of d e g l a c i a t i o n i n the ar e a : lake sediments i n the F r a s e r v a l l e y near Y a l e , 130 km south east of the study s i t e , date back to 11,430 +150 years B.P. (Mathewes et a l . , 1972); and bones from Lochore Creek, 40 km north east of the watershed, have been dated to 11,285 +100 years B.P. (Ryder, 1981). In the Goat Meadows watershed the immediate p o s t g l a c i a l p e r i o d was c o l d and wet. T h i s corresponds to a s i m i l a r r e g i o n a l p a t t e r n , when there probably were l o c a l i s e d resurgences of remanent P l e i s t o c e n e g l a c i e r s ( A l l e y , 1976; Clague, 1981). The subsequent i n t e r v a l , c a . 10,000 to 6,500 years B.P., c o r r e s -ponds very c l o s e l y to the p e r i o d of maximum temperature-minimum p r e c i p i t a t i o n , r e c ognised i n lowland s i t e s as the "xerothermic h y p s i t h e r m a l i n t e r v a l " . Snowpacks i n the Goat Meadows watershed 33 in t h i s p e r i o d may have been reduced by as much as 50%, and the v e g e t a t i o n became s i g n i f i c a n t l y more a r b o r e a l . The onset of n e o g l a c i a t i o n appears to have been soon a f t e r 6000 years B.P. Although i t i s probable that i n the southern Coast Mountains temperatures, and t h e r e f o r e t r e e l i n e s , were higher than at present u n t i l c a . 5,200 years ago (Lowdon and Blake, 1968; Clague, 1981). Rouse has i n t e r p r e t e d an i n t e r v a l i n the uppermost 10 cm of the lake c o r e s , which i s c h a r a c t e r i s e d by a dramatic drop in t e r r e s t r i a l palynomorphs accompanied by a sharp i n c r e a s e i n a l g a l c y s t s , as one r e p r e s e n t i n g a p e r i o d of d e t e r i o r a t i n g c l i m a t e , l e a d i n g to i n c r e a s e d s n o w f a l l and a p r o l o n g i n g of snow cover, thereby p r e v e n t i n g the s p o r e s / p o l l e n r e a c h i n g the lake sediments. Such a c l i m a t i c s h i f t c o u l d be r e l a t e d to pul s e s of g l a c i a l advance, i n which snow and i c e cover c o u l d have been depressed c a. 300 m below the present permanent snow l e v e l s ( ca. 2150 m). Such p u l s e s i n g l a c i a l advance have been documented i n other mountains i n the pro v i n c e by A l l e y (1976); Duford and Osborn (1978) and Ryder et a l . (1981). Furthermore, the depauperate s p o r e / p o l l e n i n t e r v a l corresponds c l o s e l y to the i n t e r v a l of depressed average J u l y temperatures recorded by Heusser (1977) 800-1000 years B.P. f o r the P a c i f i c s l o p e s ( G a l l i e , 1983; Rouse, p e r s . comm.). 34 CHAPTER 4 FIELD AND LABORATORY METHODS Fieldwork was conducted i n order to determine the d i s t r i -b u t i o n of the l a c u s t r i n e sediments and the t e r r e s t r i a l d e p o s i t s of the Goat Meadows watershed, and to c o l l e c t samples of these f o r t h e i r c h a r a c t e r i s a t i o n i n the l a b o r a t o r y . T h i s chapter d i s c u s s e s the methods used i n the c o l l e c t i o n of the samples and the subsequent l a b o r a t o r y a n a l y s e s . 4. 1 Fieldwork 4.1.1 Sampling of the lake sediments Co n v e n t i o n a l sampling s t r a t e g i e s i n small lakes remove cor e s from the deepest or c e n t r a l zone of the l a k e , a c h o i c e not based on p r i o r knowledge of sediment accumulation p a t t e r n s , but on g e n e r a l l y accepted n o t i o n s of constant and conformable accumulation away from the shallow margins of a l a k e , known as "sediment f o c u s i n g " (Lehman, 1975). However, recent s t u d i e s of s p a t i a l v a r i a t i o n s i n sediment accumulation (Bloemandal et a l . , 1979; Dearing et a l . , 1981; Dearing, 1983) do not support the concept of sediment f o c u s i n g , but i l l u s t r a t e the complex nature of sedimentation i n many small l a k e s . In order to obt a i n a r e p r e s e n t a t i v e coverage of a l l the sedimentary environments i n G a l l i e Pond, the sampling s i t e s were s e l e c t e d using a 2 x 2 m g r i d , which was imposed from a b a s e l i n e l a i d along the northern edge of the pond, from which t r a n s e c t s were run acr o s s the l a k e . In t o t a l , twenty-six cores were c o l l e c t e d (Figure 4.1), ranging i n l e n g t h from 0.22 to 0.56 m. A l l but three of the cores p e n e t r a t e d i n t o the t i l l 35 Figure 4.1 Coring locations in G a l l i e Pond N 10 m T i l l shelf . Coring location N.B. For bathymetry of lake see Figure 3.4 36 u n d e r l y i n g the lake sediments. A d d i t i o n a l i n f o r m a t i o n on s e d i -ment depth w i t h i n the lake was obtained through the use of a probe along each of the t r a n s e c t s , a method which was s a t i s f a c -t o r y because of the marked change i n sediment r e s i s t a n c e at the t i l l s u r f a c e . The c o r i n g apparatus c o n s i s t e d of 1.83 m lengths of extruded p l a s t i c (abs) p i p i n g which were d r i v e n i n t o the sediments using a m a l l e t , with a p i e c e of plywood p l a c e d over the top of the pipe to prevent i t from s h a t t e r i n g . Each of the lengths had been cut along one s i d e and scored along the oppo s i t e s i d e , and d u r i n g i n s e r t i o n were h e l d together by f i b r e tape and j u b i l e e c l i p s . T h i s a d a p t a t i o n was designed to enable the pipes to be cut open on t h e i r r e t u r n to the l a b o r a t o r y with minimum d i s t u r b a n c e to the co n t a i n e d sample, and thus to overcome the problem of compaction d u r i n g e x t r u s i o n . Two s i z e s of pipe were used, with outer diamaters 32 and 50 mm, and inner diameters 30 and 48 mm r e s p e c t i v e l y . The l a r g e r diameter was p r e f e r a b l e i n terms of the volume of m a t e r i a l i t sampled per u n i t depth, but the 32 mm p i p i n g had the advantage of being much e a s i e r to i n s t a l l and remove. In g e n e r a l , the smaller diameter pipes were i n s t a l l e d around the edge of the l a k e , while the l a r g e r ones were used i n the c e n t r e of the l a k e . In order to minimise d i s t u r b a n c e of the lake sediments, the pipes were i n s t a l l e d by moving s y s t e m a t i c a l l y from the east to the west of the lake , and no cores were removed u n t i l a l l p i p e s had been put i n p l a c e . A f t e r i n s e r t i o n , d e t a i l e d mapping of the bathymetry of the lake and sampling l o c a t i o n s was con-37 ducted using a Wild RK 1 a l i d a d e and plane t a b l e . The cores were removed from the lake and the o v e r l y i n g water c o n t a i n e d w i t h i n the extruded p l a s t i c p i p i n g was c a r e f u l l y d r a i n e d o f f to minimise mixing and d i s r u p t i o n of m a t e r i a l at the sediment-water i n t e r f a c e . The p o r t i o n of the p i p i n g c o n t a i n i n g the sediment sample, was cut o f f , wrapped in p l a s t i c wrap and aluminium f o i l , and t r a n s p o r t e d to the l a b o r a t o r y . 4.1.2 Sampling of the h i l l s l o p e d e p o s i t s In order to sample the h i l l s l o p e s u r f i c i a l sediments of the Goat Meadows watershed, the catchment was s t r a t i f i e d a c c o r -ding to the s o i l - v e g e t a t i o n u n i t s i d e n t i f i e d by G a l l i e (1983) (Figure 3.6). Samples were c o l l e c t e d on s i x t r a n s e c t s o r t h o -gonal to G a l l i e Pond (Figure 4.2). D u p l i c a t e p i t s were dug and sampled i n each of the u n i t s to ensure that the c o v a r i a n c e between v e g e t a t i o n and s o i l s was as strong as that suggested by G a l l i e (1983). The p r o f i l e s at each s i t e were d e s c r i b e d and c l a s s i f i e d a c c o r d i n g to the Canadian system of c l a s s i f i c a t i o n (Canada S o i l Survey Committee, 1978); r e p r e s e n t a t i v e pedons are d e s c r i b e d i n Appendix I. Samples of approximately 500 g of the <5 mm f r a c t i o n were c o l l e c t e d from each of the m o r p h o l o g i c a l l y d i f f e r e n t h o r i z o n s and re t u r n e d to the l a b o r a t o r y f o r a n a l y s i s . 4 . 2 Laboratory methods 4.2.1 P r e p a r a t i o n of f i e l d samples A l l the cores were photographed and d e s c r i b e d i n terms of the l i t h o s t r a t i g r a p h i c u n i t s present, t e x t u r e and c o l o u r (using 38 F i g u r e 4.2 S o i l s a m p l i n g l o c a t i o n s i n t h e Goat Meadows watershed 39 the Munsell c o l o u r c h a r t ) . Greater d e t a i l s of the sedimentary s t r u c t u r e s present were obtained with an Olympus Sz III o p t i c a l microscope. Samples were taken from a l l of the c o r e s , from each of the s t r a t i g r a p h i c u n i t s , f o r the d e t e r m i n a t i o n of pH, mois-ture content, organic matter content and bulk d e n s i t y . The outer l a y e r s of the cores which may have been smeared along the core tube d u r i n g i n s e r t i o n were d i s c a r d e d and the c e n t r a l p o r t i o n s remaining were a i r d r i e d and s t o r e d f o r subsequent more d e t a i l e d a n a l y s e s . The bulk s o i l samples were subsampled on a r r i v a l at the l a b o r a t o r y f o r pH, and f i e l d moisture d e t e r m i n a t i o n s , the remainder was a i r d r i e d at room temperature. The s o i l s were s i e v e d to pass a 2 mm s i e v e . Large p i e c e s of organic matter were removed by hand or r e s i e v i n g . L o g i s t i c a l c o n s t r a i n t s l e d to many of the more d e t a i l e d p h y s i c a l , chemical and m i n e r a l o g i c a l analyses being conducted on a l i m i t e d number of lake sediment and s o i l samples. Using the c r i t e r i a of g r e a t e s t accumulation and r e p r e s e n t a t i v e n e s s of a l l the s t r a t i g r a p h i c u n i t s p r esent, core F1 was s e l e c t e d as a "master co r e " on which these analyses were conducted, and a g a i n s t which a l l other cores were c r o s s - c o r r e l a t e d (Appendix IV) . A number of the a n a l y s e s were conducted on s e v e r a l cores i n order to assess the r e p r e s e n t a t i v e n e s s of the r e s u l t s of the master core, and to o b t a i n some i n d i c a t i o n of s p a t i a l v a r i a b i l i t y i n sedimentary c h a r a c t e r i s t i c s . The master core was s u b d i v i d e d i n t o ten s t r a t i g r a p h i c u n i t s ( s e c t i o n 5.1.1). A f t e r p a r t i c l e s i z e a n a l y s i s was performed the i n d i v i d u a l u n i t s were 40 w e l l mixed. The m a t e r i a l i n the Bridge River and Mazama ash h o r i z o n s was supplemented with sediment from these h o r i z o n s i n cores E1 and E2, in order to o b t a i n s u f f i c e n t m a t e r i a l on which to conduct the a n a l y s e s . The s o i l pedons d e s c r i b e d i n Appendix I are those used f o r a n a l y s i s . Table 4.1 summarises the samples used i n each of the a n a l y s e s . D u p l i c a t e s were run i n a l l cases i n order to determine the e r r o r s i n each of the l a b o r a t o r y techniques; these are s t a t e d where a p p r o p r i a t e . 4.2.2 P h y s i c a l a n a l y s e s 4.2.2.1 Bulk d e n s i t y , moisture and o r g a n i c matter content Known volumes of each sample were weighed in order to a s c e r t a i n the wet bulk d e n s i t y ( H i l l e l , 1971). The samples were oven d r i e d f o r 24 hours at 105°C f o r the d e t e r m i n a t i o n of dry bulk d e n s i t y and moisture content ( H i l l e l , 1971), and then p l a c e d i n a m u f f l e furnace at 450°C f o r 3 hours to determine l o s s on i g n i t i o n , a surrogate f o r organic matter content ( L a v k u l i c h , 1981), and f o r the assessment of the c l a s t i c s e d i -ment bulk d e n s i t y ( H i l l e l , 1971). 4.2.2.2 P a r t i c l e s i z e a n a l y s i s P a r t i c l e s i z e a n a l y s i s of the l e s s than 2 mm (<-1tf>) f r a c -t i o n was conducted using standard dry s i e v i n g techniques and a SediGraph 5000 a n a l y s e r . F o l l o w i n g the removal of organic matter by i g n i t i o n ( s e c t i o n 4.2.2.1), samples of approximately 10 g were l i g h t l y crushed with a p e s t l e and mortar to break up any l a r g e aggregates, and were then dry s i e v e d from 2 mm (-1$) 41 Table 4.1 Sample s i z e s used i n l a b o r a t o r y analyses C h a r a c t e r i s t i c Technique Sample used Bulk d e n s i t y Organic matter Texture Mineralogy pH E x t r a c t a b l e Fe and A l T o t a l element Organic Carbon Organic n i t r o g e n Core method Loss on i g n i t i o n Dry s i e v i n g , SediGraph X-ray d i f f r a c t i o n pH meter D i t h i o n i t e - c i t r a t e -b i c a r b o n a t e e x t r a c t i o n T e f l o n bomb e x t r a c t i o n , I CAP Walkley-Black t i t r a t i o n Colour i m e t r i c a l l y a u t o - a n a l y s e r A l l * A l l At r e g u l a r i n t e r v a l s in a l l s t r a t i g . u n i t s cores C2, F1, 11, s u r f a c e sediments cores B2, C1, D3, F2, R1 , V1 F1 A l l F1 F1 F1 F1 N.B. *- A l l s t r a t i g r a p h i c u n i t s i n a l l cores 42 to 63 Mm (40), using s i e v e s with 1/20 spacings, employing the standard techniques d e s c r i b e d by G r i f f i t h s (1967) and Bray (1972). A l l measurements of weight were r e p o r t e d to the nearest 0.01 g. A sample of 1.5-2.0 g of that m a t e r i a l r e t a i n e d on the 63 Mm s i e v e was d i s p e r s e d i n sodium hexametaphosphate using a sonic bath, and run on a SediGraph 5000 a n a l y s e r . The o p e r a t i n g procedure that was used i s documented i n M i c r o m e t r i c s (1978). The SediGraph measures the sedimentation r a t e s of p a r t i c -l e s i n suspension and p r e s e n t s these data as a cumulative percent f i n e r d i s t r i b u t i o n i n terms of the S t o k e s i a n e q u i v a l e n t ( s p h e r i c a l d i a m e t e r ) . The t h e o r e t i c a l p r i n c i p l e s are summa-r i s e d i n Karasek (1970) and M i c r o m e t r i c s (1978). The cumulative p l o t s produced i n t h i s a n a l y s i s were d i g i t i s e d and combined with the s i e v e data to c a l c u l a t e the graphic s t a t i s t i c s of Folk and Ward (1957), the computational forms of which are r e p o r t e d i n Table 4.2. 4.2.3 M i n e r a l o g i c a l analyses The mineralogy of the <2 um f r a c t i o n was determined through the use of X-ray d i f f r a c t i o n (X.R.D.), the p r i n c i p l e s of which are d e s c r i b e d by C a r o l l (1970). Samples of a p p r o x i -mately 20 g of sediment were t r e a t e d f o r the removal of organic matter, carbonates and f r e e i r o n oxides, before the <2 nm f r a c t i o n was separated out by c e n t r i f u g a t i o n . O r i e n t e d s l i d e s which had undergone f i v e treatments (Mg s a t u r a t i o n ; Mg s a t u r a -t i o n and g l y c o l s o l v a t i o n ; K s a t u r a t i o n ; K s a t u r a t i o n and heated to 300°C; K s a t u r a t i o n and heated to 500°C) were pre-43 Table 4.2 P a r t i c l e s i z e a n a l y s i s : computational form of graphic s t a t i s t i c s (Folk and Ward, 1957) S t a t i s t i c Computational form Graphic mean (Mz) (016 + 050 + 084) 3 I n c l u s i v e graphic standard d e v i a t i o n ( a i ) 084 - 016 + 095 - 05 4 6.6 I n c l u s i v e graphic skewness (Ski) 016 + 084 ~ 2050 + 05 + 095 -2050 2(084 - 016) 2(095 - 05) Graphic k u r t o s i s (KG) 095 - 05 2.44 (075 - 025) Normalised graphic k u r t o s i s (KG') KG (1 + KG) 44 pared in accordance with the procedures developed by the Unive-r s i t y of B r i t i s h Columbia's S o i l Science Laboratory ( L a v k u l i c h , 1981). I d e n t i f i c a t i o n of the mi n e r a l s present i n each sample was conducted through the comparison of the X-ray d i f f r a c t i o n p a t t e r n s with standard r e f e r e n c e t a b l e s of r e f l e c t i o n s r e p o r t e d i n B r i n d l e y and Brown (1980) and L a v k u l i c h (1981). 4.2.4 Chemical analyses 4.2.4.1 Measurement of pH Sediment pH was determined i n water (1:1) and i n 0.01 m C a C l 2 (Black, 1965) using a F i s h e r Acumet pH meter model 620. 4.2.4.2 D i t h i o n i t e e x t r a c t a b l e i r o n and aluminium The d i t h i o n i t e - c i t r a t e - b i c a r b o n a t e e x t r a c t i o n procedure of Mehra and Jackson (1960) was conducted on 2 g unground samples of <2 mm as o u t l i n e d by L a v k u l i c h (1981). The c o n c e n t r a t i o n s of i r o n and aluminium were determined from the e x t r a c t s on a Perkin-Elmer 306 atomic a b s o r p t i o n spectrophotometer. Values were c a l c u l a t e d i n both ppm and % of sediment. » 4.2.4.3 T o t a l element a n a l y s i s T o t a l element a n a l y s i s was conducted using the t e f l o n bomb e x t r a c t i o n procedure (Rantala and L o r i n g , 1973), the method f o r which i s d e s c r i b e d by L a v k u l i c h (1981). The c o n c e n t r a t i o n s of 23 elements ( A l , As, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mo, Na, N i , P, Se, S i , Sr, T i , Zn, Zr) were determined s i m u l t a n e o u s l y using a J a r e l l - A s h Adam Comp, 1100 s e r i e s ICAP and converted i n t o ppm 45 and % of sediment. 4.2.4.4 Organic carbon and n i t r o g e n Organic carbon was determined by the Walkley-Black t i t r i m e t r i c method (Black, 1965). T o t a l n i t r o g e n was determined c o l o u r i m e t r i c a l l y by auto a n a l y s e r ( L a v k u l i c h , 1981). 46 CHAPTER 5 RESULTS AND DISCUSSION T h i s chapter w i l l present the r e s u l t s of the p h y s i c a l , m i n e r a l o g i c a l and chemical analyses o u t l i n e d i n chapter 4. These w i l l be d i s c u s s e d i n the context of the f i r s t three of the more s p e c i f i c o b j e c t i v e s of t h i s study (enumerated i n s e c t i o n 1.3): s e c t i o n 5.1 i s concerned with the temporal and s p a t i a l v a r i a b i l i t y of sedimentary c h a r a c t e r i s t i c s of G a l l i e Pond; s e c t i o n 5.2 with the temporal v a r i a b i l i t y of sediment y i e l d from the Goat Meadows watershed; and, s e c t i o n 5.3 with the i d e n t i f i c a t i o n of sediment source areas and t h e i r v a r i a t i o n over the Holocene p e r i o d . Data of both the lake sediments and watershed s o i l s w i l l be i n c o r p o r a t e d . The chronology of events f o r the study i s p r o v i d e d through two radiocarbon dates and the p o s i t i v e i d e n t i f i c a t i o n of Bridge R i v e r and Mazama tephra i n the sediments of G a l l i e Pond (Appendix I I I ) . The r e s u l t s w i l l be i n t e g r a t e d and d i s c u s s e d i n s e c t i o n s 5.4 and 5.5 i n the context of the o v e r a l l o b j e c t i v e of t h i s study: the i n f e r e n c e of palaeogeomorphic processes over the Holocene Epoch. 5.1 Temporal and s p a t i a l v a r i a b i l i t y of sedimentary  c h a r a c t e r i s t i c s 5.1.1 S t r a t igraphy The l i t h o s t r a t i g r a p h y of the d e p o s i t s i n G a l l i e Pond provi d e s a continuous imprint of changes i n sedimentation and palaeoenvironments. T h i s i s i n d i c a t e d by the u n d i s t u r b e d nature of the d e p o s i t s , most notab l y the Bridge R i v e r ash, which i s 47 continuous throughout the lake with very d i s t i n c t boundaries with the over and u n d e r l y i n g 'sediment, i n d i c a t i n g l i t t l e mixing or r e d i s t r i b u t i o n of the sediments once i n the l a k e . The major l i t h o s t r a t i g r a p h i c u n i t s of each core are i l l u s t r a t e d i n Appendix IV. A l l the cores e x h i b i t sharp and s i g n i f i c a n t changes in t h e i r d e p o s i t i o n a l r e c o r d s , the major f e a t u r e s of which are the a l t e r n a t i o n s between peats, h i g h l y organic s i l t s and i n o r g a n i c sediments, which occur i n a f a i r l y r e g u l a r manner i n each of the c o r e s . The s t a t i g r a p h y of the master core, F.I, i s shown i n F i g u r e 5.1. T h i s core was s e l e c t e d , f o r i t s r e p r e s e n t a t i v e e x p r e s s i o n of the d i f f e r e n t s t r a t i g r a p h i c u n i t s present i n the lake sediments ( s e c t i o n 4.2.1), and p r o v i d e s a u s e f u l standard f o r comparison i n the d e t e r m i n a t i o n of s p a t i a l v a r i a t i o n s i n l i t h o s t r a t i g r a p h y . At the base of the master core o v e r l y i n g the coarse sand/ g r a v e l l y t i l l i s a shallow d e p o s i t (4 cm) of dark g r a y i s h brown s i l t s (Munsell c o l o u r 10 YR 5/2) e n r i c h e d with fragments of f a i r l y w e l l decomposed or g a n i c matter. Above t h i s i s a s u b s t a n t i a l accumulation of peat (25 cm) with woody segments. In the upper t h i r d of t h i s d e p o s i t i s a d i s c o n t i n u o u s l a y e r of Mazama ash, a very pale brown/orange (10 YR 7/6), f i n e t e x t u r e d d e p o s i t with a maximum t h i c k n e s s of 0.5 cm. The Mazama ash i s not continuous throughout the l a k e , but i s c o n c e n t r a t e d i n lenses of d e p o s i t i o n . The peat i s o v e r l a i n by dark gray s i l t s (10 YR 4/1) (6 cm) e n r i c h e d with organic matter which grade i n t o i n o r g a n i c sediments (4 cm). A s u b s t a n t i a l d e p o s i t 48 Figure 5.1 Stratigraphy of the master core 0 I — n — m — r -E o •H xi 4J a> Q 10 20 30 40 50' + + • + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Lacustrine s i l t s Bridge River ash Lacustrine s i l t s Lacustrine s i l t s & Organic matter Peat Mazama ash Peat Lacustrine s i l t s & Organic matter T i l l 49 (2-3 cm) of Bridge River ash occurs i n the top 5-15 cm of a l l c o r e s . In many of the cores t h i s i s i n f a c t two d i s t i n c t u n i t s : the lower, much coars e r unweathered shards of ash; the upper, a much f i n e r d e p o s i t , a product of f i n e r ash f a l l o u t i ntermixed with watershed sediments. The uppermost lake sediments (9 cm) are g r a y i s h brown (10 YR 5/2) i n o r g a n i c l a c u s t r i n e s i l t s , which become l e s s w e l l c o n s o l i d a t e d near the s u r f a c e . These e i g h t d i s t i n c t p o s t g l a c i a l l i t h o s t r a t i g r a p h i c u n i t s are represented i n a f a i r l y r e g u l a r f a s h i o n throughout the l a k e . A f u r t h e r u n i t i s i d e n t i f i e d f o r subsequent analyses through the s u b d i v i s i o n of the s u r f a c e s i l t s i n t o w e l l c o n s o l i d a t e d and l e s s w e l l c o n s o l i d a t e d h o r i z o n s (although t h i s i s not ev i d e n t i n the master c o r e ) . Other s t r a t i g r a p h i c u n i t s present but not evident i n the master core i n c l u d e coarse sand/gravel d e p o s i t s i n cores V1 and V2, both i n the v i c i n i t y of the incoming Hummingbird stream, and a t h i n , d i s c o n t i n u o u s d e p o s i t of black c h a r c o a l i n cores C1 and H1, approximately 11 cm above the t i l l w i t h i n the peat u n i t , which may be i n t e r p r e t e d as i n d i c a t i v e of a f i r e i n the catchment i n e a r l y p o s t g l a c i a l time. Throughout much of the lake s t r o n g brown (7.5 YR 5/8) o x i d i z e d sands o v e r l i e the t i l l , r e p r e s e n t i n g c o n d i t i o n s of f l u c t u a t i n g water l e v e l d u r i n g the i n i t i a l p e r i o d of pond formation. The s i g n i f i c a n t changes i n the s t r a t i g r a p h y of the sediments of G a l l i e Pond may be i n t e r p r e t e d as i n d i c a t i v e of changes i n the water balance of the lake and may be used to 50 i n f e r changes i n p a l a e o c l i m a t e and c o n s e q u e n t l y movements o f t h e t r e e l i n e wh ich have o c c u r r e d and a f f e c t e d the Goat Meadows w a t e r s h e d over t he Holocene Epoch. For example , t h e woody p e a t s i n d i c a t e an e n v i r o n m e n t t h a t was s i g n i f i c a n t l y d r i e r t h a n a t p r e s e n t and p o s s i b l y warmer w i t h reduced snowpacks. C o n s e q u e n t l y t he t r e e s were a b l e t o advance i n t o t h i s a rea t h a t c u r r e n t l y has t o o s h o r t a g r o w i n g season . Th is , advance i s e v i d e n c e d by t h e p resence o f many undecomposed n e e d l e s i n t h e d e p o s i t s . D u r i n g t h i s p e r i o d t h e w a t e r l e v e l f e l l and the pond d e v e l o p e d i n t o a pea t b o g . Peat g r o w t h has been succeeded by i n o r g a n i c c l a s t i c sed iment d e p o s i t s wh ich i n d i c a t e f l o o d i n g o f t h e s i t e t o fo rm a s h a l l o w l a k e . The most r e c e n t i n o r g a n i c u n i t s r e p r e s e n t an e n v i r o n m e n t w i t h i n c r e a s e d f l u v i a l r u n o f f and sed iment y i e l d . The c o a r s e sand h o r i z o n s i n t h e c o r e s V1 and V2 r e p r e s e n t p e r i o d s o f i n c r e a s e d e r o s i o n a l a c t i v i t y i n t h e Hummingbi rd subcatchment and t h e f l u v i a l i n p u t o f c o a r s e sand i n t h e e a r l y p o s t g l a c i a l i n t e r v a l . The s t r a t i g r a p h y o f t h e d e p o s i t s i s an i m p o r t a n t i n d i c a t o r o f m i n c r o g e n i c b u l k d e n s i t i e s and o r g a n i c m a t t e r c o n t e n t o f t h e s e d i m e n t s . I n g e n e r a l f o u r main c l a s s e s can be i d e n t i f i e d : t h e t i l l and o x i d i z e d sands w i t h h i g h b u l k d e n s i t y and low o r g a n i c m a t t e r c o n t e n t ; t h e p e a t y h o r i z o n s and t h o s e s i l t s e n r i c h e d w i t h o r g a n i c m a t t e r , w i t h h i g h o r g a n i c m a t t e r c o n t e n t and t h e l o w e s t c l a s t i c sed iment b u l k d e n s i t y ; t he ash l a y e r s w i t h t h e h i g h e s t v a l u e s of b u l k d e n s i t y and l o w e s t o r g a n i c m a t t e r c o n t e n t ; and t h e uppermost s e d i m e n t s , w i t h i n t e r m e d i a t e v a l u e s o f o r g a n i c m a t t e r and b u l k d e n s i t y . 51 5.1.2 Minerogenic bulk d e n s i t y Minerogenic bulk d e n s i t y was determined p r i m a r i l y to convert the volume of accumulated sediment i n the lake i n t o a mass of c l a s t i c sediment; however, the values e x h i b i t d i s t i n c t i v e temporal v a r i a t i o n which may be r e l a t e d to the s t r a t i g r a p h i c u n i t s i n the lake sediments. The minerogenic bulk d e n s i t y (dry mass c l a s t i c sediment/unit volume) v a r i e s between 250 kg/m3 and 1380 kg/m3 f o r the d i f f e r e n t s t r a t i g r a p h i c u n i t s of the master core, F.1 (Fi g u r e 5.2). The d e n s i t y shows peaks i n the Bridge R i v e r , and to a l e s s e r extent, the Mazama ash h o r i z o n s , and i s lowest i n the peaty u n i t s and those e n r i c h e d with organic matter. Mean minerogenic bulk d e n s i t i e s f o r the d i f f e r e n t s t r a t i g r a p h i c h o r i z o n s of the lake sediments of G a l l i e Pond are re p o r t e d i n Table 5.1. Values were determined f o r samples taken from each of the s t r a t i g r a p h i c u n i t s i n each of the cores ( s e c t i o n 4.2.1). Some i n d i c a t i o n of the v a r i a b i l i t y of these values (both s p a t i a l and temporal) f o r each of the s t r a t i g r a p h i c u n i t s i s p r o v i d e d through the p r e s e n t a t i o n of the c o e f f i c e n t of v a r i a t i o n , which i s an index of v a r i a b i l i t y (Snedecor and Cochran, 1980) determined as: C o e f f i c e n t of v a r i a t i o n = Standard d e v i a t i o n (5.1) Mean For the purposes of t h i s d i s c u s s i o n , the higher the c o e f f i c e n t of v a r i a t i o n the grea t e r v a r i a b i l i t y . The g r e a t e s t values can be noted i n the peaty h o r i z o n s , and the lowest i n the l a c u s t r i n e s i l t s o v e r l y i n g these. F i g u r e 5.3 i l l u s t r a t e s the p a t t e r n of Lgure 5.2 Temporal v a r i a b i l i t y down the master c o r e o f : a) M i n e r o g e n i c b u l k d e n s i t y b) O r g a n i c m a t t e r c o n t e n t c) O r g a n i c Carbon d) N i t r o g e n e) C:N r a t i o s (a) (b) (c) (d) (e) (kg/m3) (% wt.) (%) (%) 53 Table 5.1 Minerogenic bulk d e n s i t i e s by s t r a t i g r a p h i c h o r i z o n (kg/m 3) S t r a t i g r a p h i c u n i t n x S.D. C.V. Upper l a c u s t r i n e s i l t s 52 L a c u s t r i n e s i l t s 54 L a c u s t r i n e s i l t s / B ridge R i v e r ash 5 L a c u s t r i n e s i l t s / o rganic matter 42 P e a t / l a c u s t r i n e s i l t s 52 Peat/Mazama ash 4 Peat 52 L a c u s t r i n e s i l t s / o rganic matter 52 870 120 0.14 880 140 0.16 1350 230 0.17 420 40 0.09 290 60 0.21 730 120 0.16 220 40 0.18 320 30 0.10 F i g u r e 5.3 S p a t i a l v a r i a b i l i t y o f m i n e r o g e n i c b u l k d e n s i t y i n t h e s u r f a c e s e d i m e n t s o f G a l l i e Pond 55 the s p a t i a l v a r i a b i l i t y of d e n s i t y v a l u e s i n the top l a c u s t r i n e u n i t . The valu e s are lowest i n the deepest p a r t of the l a k e , although there i s no c o n s i s t e n t t r e n d with water depth. V a r i a t i o n s i n the values of minerogenic bulk d e n s i t y e x h i b i t a s t r o n g i n v e r s e r e l a t i o n s h i p with o r g a n i c matter content (r=-0.31, n=85, s i g n i f i c a n t at p=0.0l). The most important f a c t o r i n c o n t r o l l i n g both s p a t i a l and temporal v a r i a b i l i t y appears to be depth ( F i g u r e 3.4), hence the t h i c k -ness of peat, which grows best at the lowest p o i n t of the lake hollow. A d d i t i o n a l f a c t o r s of importance i n e x p l a i n i n g the v a r i a b i l i t y are the water content of the sample, the overburden/degree of compaction, the t e x t u r a l c h a r a c t e r i s t i c s and packing. 5.1.3 Organic matter content The l o s s on i g n i t i o n at 450°C f o r three hours was taken as a measure of the organic matter content of the sediment ( s e c t i o n 4.2.2.1). Values f o r the master core range between 1.2% and 23.1% (by weight). Minimum valu e s are observed i n the o x i d i z e d sands and uppermost l a c u s t r i n e s i l t s ( F i g u r e 5.2). Table 5.2 summarises the mean va l u e s of org a n i c matter by s t r a t i g r a p h i c u n i t and i n d i c a t e s v a r i a b i l i t y through the c o e f f i c e n t of v a r i a t i o n . In gen e r a l v a r i a b i l i t y i s low, with a maximum i n the o x i d i z e d sands (C.V.=0.16), however, i n t h i s u n i t the mean i s lowest, hence the c o e f f i c i e n t of v a r i a t i o n i s the most u n s t a b l e . F i g u r e 5.4 i l l u s t r a t e s the s p a t i a l 56 Table 5.2 Organic matter content by s t r a t i g r a p h i c h o r i z o n (% by weight) S t r a t i g r a p h i c u n i t n x S.D. C.V. Upper l a c u s t r i n e s i l t s 52 7.28 0.39 0. 054 L a c u s t r i n e s i l t s 52 7.099 0.72 0. 1 02 L a c u s t r i n e s i l t s / B ridge R i v e r ash 5 2.016 0.24 0. 119 L a c u s t r i n e s i l t s / o r g a n i c matter 42 1 3.92 1 .38 0. 099 P e a t / l a c u s t r i n e s i l t s 52 18.65 2.09 0. 1 1 2 Peat/Mazama ash 4 5.33 0.56 0. 10 Peat 52 22. 1 3 1 .62 0. 073 L a c u s t r i n e s i l t s / o r g anic matter 52 18.65 1 .35 0. 072 O x i d i z e d sands 9 1 . 1 0.17 0. 16 57 Figure 5.4 Spatial v a r i a b i l i t y of the organic matter content of the surface sediments of G a l l i e Pond N Contour i n t e r v a l 0.5% m 58 v a r i a b i l i t y of organic matter content i n the s u r f a c e sediments. Values are g r e a t e s t i n the c e n t r a l part of the lake and lowest i n the v i c i n i t y of Mosquito Creek, a p a t t e r n i n accordance with the d i s t r i b u t i o n of minerogenic bulk d e n s i t y v a l u e s ( s e c t i o n 5.1.2). The temporal v a r i a b i l i t y e x h i b i t s a t r e n d that would be expected from the s t r a t i g r a p h y of the sediments, with the highest v a l u e s i n the peaty h o r i z o n s and those with v i s i b l e fragments of organic matter. The organic matter content of the s u r f a c e l a c u s t r i n e s i l t s i s s i m i l a r to that r e p o r t e d by B i r k e l a n d and Andrews (1982) f o r a l p i n e / s u b a l p i n e l a k e s i n the Colorado Front Range (5-10%). The nature of the o r g a n i c matter i n terms of a l l o c h t h o n o u s and autochthonous o r i g i n w i l l be d i s c u s s e d with regard to i t s carbon and n i t r o g e n contents i n s e c t i o n 5.1.8. 5.1.4 P a r t i c l e s i z e d i s t r i b u t i o n The t e x t u r a l c h a r a c t e r i s t i c s of a t o t a l of 46 samples were determined i n order to assess temporal and s p a t i a l v a r i a b i l i t y . Samples were s e l e c t e d to r e f l e c t changes i n d e p o s i t i o n a l environments and l i t h o s t r a t i g r a p h i c u n i t s . In order to compare the sedimentary environments q u a n t i t a t i v e l y mean s i z e , s o r t i n g , skewness and k u r t o s i s d i s t r i b u t i o n p r o p e r t i e s were c a l c u l a t e d a c c o r d i n g to the graphic s t a t i s t i c s of Folk and Ward (1957) (Table 4.2). These r e s u l t s are presented i n Appendix V and summarised by s t r a t i g r a p h i c h o r i z o n i n Table 5.3. The propor-t i o n s of s a n d / s i l t / c l a y are i l l u s t r a t e d i n a t e x t u r a l t r i a n g l e 59 Table 5.3 Summary of p a r t i c l e s i z e c h a r a c t e r i s t i c s by s t r a t i g r a p h i c h o r i z o n S t r a t i g r a p h i c n Mz(tf>) oi(tfi) Ski KG' uni t L a c u s t r i n e s i l t s 15 5.51 0.52 1.53 0.45 -0.47 0.20 0.52 0.09 L a c u s t r i n e s i l t s / B r i d g e River ash 3 3.56 0.15 1.19 0.25 0.17 0.04 0.60 0.04 L a c u s t r i n e s i l t s / o r g a n i c matter 6 5.80 0.89 1.52 0.43 -0.46 0.15 0.47 0.08 L a c u s t r i n e silts/Mazama ash 4 5.41 0.19 1.55 0.40 -0.32 0.33 0.64 0.15 Peat 5 4.82 0.37 1.41 0.02 -0.32 0.21 0.45 0.02 L a c u s t r i n e s i l t s / o r g a n i c matter 3 4.67 0.44 1.79 0.72 -0.15 0.32 0.39 0.02 T i l l / o x i d i z e d sands 6 2.27 1.44 2.24 0.69 0.15 0.33 0.46 0.08 N.B. n=42, excludes c o a r s e r sand h o r i z o n s i n core V1 60 ( F i g u r e 5.5), with sand (>63 nm) , s i l t (2-63 Min) and c l a y (<2 Mm) as i t s three a p i c e s . The mean p a r t i c l e s i z e r e f l e c t s the o v e r a l l average s i z e of the sediments and i s i n f l u e n c e d by the source of supply and the environment of d e p o s i t i o n (Folk, 1964). F i g u r e 5.6 (a,b,c) i l l u s t r a t e s the v a r i a t i o n of mean p a r t i c l e s i z e with depth i n three cores C2, F1 and 11. These i n c o n j u n c t i o n with Table 5.3 i l l u s t r a t e a f a i r l y c o n s i s t e n t , although s u b t l e , c o a r s e n i n g of the sediments with depth, with d e v i a t i o n s from the general trend in the Bridge River and Mazama ash h o r i z o n s . The major exception i s core 11 i n which the tr e n d i s more evident with a marked decrease i n the mean s i z e from the t i l l to the peaty sediments. Table 5.3 i l l u s t r a t e s t h a t the f i n e s t sediments (Mz 5.80) are found in the l a c u s t r i n e s i l t s d e p o s i t e d between the Mazama and Bridge River ash, although the most recent s i l t s (Mz 5.51c>) and the Mazama ash d e p o s i t (5.410) are of a very s i m i l a r c a l i b r e . T h i s p a t t e r n i s not evident i n the three cores i l l u s t r a t e d i n F i g u r e 5.6. In these cores the f i n e s t sediments occur i n the upper l a c u s t r i n e s i l t u n i t (5.460, 5.580 and 6.5 0 f o r cores C2, F1 and 11 r e s p e c t i v e l y ) . The c o a r s e s t sediments are the t i l l (Mz 2.270) and the Bridge R i v e r ash (Mz 3.560). The f i n e n e s s of the Mazama ash i s e x p l i c a b l e i n terms of the d i s t a n c e t o i t s source i n southern Oregon. The gen e r a l f i n i n g of the sediments may otherwise be e x p l a i n e d i n terms of e i t h e r a decrease i n the competence of the t r a n s p o r t i n g medium, or a change i n the nature of the source area and the weathering of 61 Figure 5.5 Textural tr i a n g l e 100A 0 % weight clay .50 % weight s i l t 100 100 50 % weight sand • Lacustrine s i l t s 0 • T i l l / O x i d i z e d sands O A S o i l s A Peat Ash (Bridge River & Mazama) Lacustrine s i l t s & organic matter 62 Figure 5.6 Temporal v a r i a b i l i t y of textural character for : (a) core C.2 Mz (0) 4 5.6 Sk .75 -.25 I .25 75 KG1 .5 63 F i g u r e 5.6 (continued) (b) core F l Mz(0) Sk_ KG' 2 3 4 5 6 7 -.75 -.25 .25 .4 .6 —i i i i J i i i i i i i i i i_ 65 the sediments r e s u l t i n g i n an i n c r e a s e i n the abundance of f i n e m a t e r i a l f o r e r o s i o n over time. The standard d e v i a t i o n of a p a r t i c l e s i z e d i s t r i b u t i o n i s a measure of the s o r t i n g of the sediments (Folk and Ward, 1957) and i s a u s e f u l parameter to d e s c r i b e the e f f e c t of flow on d e p o s i t i o n (Keulder, 1982). In w e l l s o r t e d sediments (a i 0-0.75) a constant h y d r a u l i c flow i s i n d i c a t e d , while p o o r l y s o r t e d sediments ( a i >2.0 ) i n d i c a t e f l u c t u a t i n g h y d r a u l i c c o n d i t i o n s ( V i s h e r , 1969). F i g u r e 5.6 (a,b,c) shows the standard d e v i a t i o n v a l u e s (+2ai) p l o t t e d as e r r o r bars around the mean. These f i g u r e s i n c o n j u n c t i o n with Table 5.3 show that the degree of s o r t i n g of sediments has v a r i e d over time although not s i g n i f i c a n t l y . The Bridge River ash d e p o s i t s appear to be the best s o r t e d ( a i 1.190), the lower l a c u s t r i n e s i l t s and organic matter the l e a s t w e l l s o r t e d ( a i 1.790), while the peaty h o r i z o n s show the most c o n s i s t e n c y (standard d e v i a t i o n of ai 0.020). A l l of the s t r a t i g r a p h i c u n i t s would be d e s c r i b e d as moderately s o r t e d , with the exception of the t i l l / o x i d i z e d sands which are p o o r l y s o r t e d a c c o r d i n g to Friedman's (1962) c r i t e r i a . T h i s i s p r i m a r i l y a consequence of the s i z e of the lake b a s i n and the c o n s i d e r a b l e mixing of sediments from a number of d i f f e r e n t sources: f l u v i a l , a e o l i a n and mass wasting. Skewness i s a measure of the d i s t r i b u t i o n about the mean. The parameter i s r e l a t e d to the environmental energy i n v o l v e d in the movement of p a r t i c l e s (Stephenson, 1970). A p o s i t i v e skewness i n d i c a t e s more l a r g e p a r t i c l e s than expected from a 66 normal d i s t r i b u t o n of s i z e s , with a t a i l i n the f i n e s . The converse i s t r u e with negative skewness (Keulder, 1982). The sediments of G a l l i e Pond have a dominantly negative skewness i n d i c a t i n g a predominance of f i n e sediments and a t a i l i n the d i r e c t i o n of the coarse p a r t i c l e s . The major ex c e p t i o n s are the Bridge River and t i l l h o r i z o n s which are p o s i t i v e l y skewed. The trends down the three cores C2, F1 and 11 are f a i r l y c o n s i s -t e n t , although as can be seen from the standard d e v i a t i o n s f o r each of the u n i t s there i s some degree of s p a t i a l v a r i a b i l i t y between the d i f f e r e n t samples. In general these skewness values i n d i c a t e environments with r e l a t i v e l y low energy, i n which the predominant e r o s i o n a l events t r a n s p o r t e d f i n e r m a t e r i a l , with l e s s frequent movement of the c o a r s e r f r a c t i o n . The exc e p t i o n s are the Bridge River and t i l l h o r i z o n s , the product of tephra f a l l o u t from a nearby source and g l a c i a t i o n r e s p e c t i v e l y . I t i s probable that the other sedimentary u n i t s were d e r i v e d from the winnowing of t e r r e s t r i a l d e p o s i t s , s e l e c t i v e l y removing f i n e r m a t e r i a l . K u r t o s i s i s a dimensionless value that i n d i c a t e s the r a t i o of the c e n t r a l s i z e f r a c t i o n to the f i n e r and c o a r s e r s i z e f r a c t i o n s . A value of 0.5 i n d i c a t e s a normal degree of s o r t i n g . A value above 0.5 i n d i c a t e s a sample i n which there i s more i n the c e n t r a l f r a c t i o n than might be expected i n r e l a t i o n to the amounts of f i n e r and c o a r s e r f r a c t i o n s , such a d i s t r i b u t i o n i s termed l e p t o k u r t i c . I f the value i s l e s s than 0.5 the s i t u a t i o n i s r e f e r r e d to as p l a t y k u r t i c . 67 If account i s taken of both the k u r t o s i s values and t h e i r standard d e v i a t i o n s r e p o r t e d i n Table 5.3 a l l h o r i z o n s , with the exception of the Bridge River ash (KG' 0.60) which i s l e p t o k u r t i c , and the l a c u s t r i n e s i l t s and organic matter (KG' 0.39) which i s p l a t y k u r t i c , may best be d e s c r i b e d as normal a c c o r d i n g to F o l k ' s (1964) c r i t e r i a . The v a r i a b i l i t y of the k u r t o s i s v a l u e s i s such that i t i s d i f f i c u l t t o i n t e r p r e t the r e s u l t s i n terms of environments of d e p o s i t i o n and e r o s i o n . F i g u r e 5.7 (a,b,c,d) i l l u s t r a t e s the s p a t i a l v a r i a b i l i t y of the t e x t u r a l c h a r a c t e r i s t i c s of the sur f a c e sediments i n G a l l i e Pond. The p a t t e r n of mean p a r t i c l e s i z e ( F i g u r e 5.7 a) and the degree of s o r t i n g (Figure 5.7 b) i s as would be expected, coarse l e s s w e l l s o r t e d sediments near the margins of the lake , f i n e r w e l l s o r t e d sediments i n the c e n t r e . T h i s p a t t e r n i s the product of f l u v i a l input from Mosquito and Hummingbird Creeks which has r e s u l t e d i n the c o n s t r u c t i o n of small l e s s w e l l s o r t e d d e l t a s , with the f i n e r sediment i n the ce n t r e of the l a k e , and slumping from the t i l l s h e l f and h i l l s l o p e s i n t r o d u c i n g coarse unsorted m a t e r i a l t o the system, a l l the way around the edge of the l a k e . A l l the s u r f a c e h o r i z o n s are n e g a t i v e l y skewed with a c o n s i d e r a b l e range of k u r t o s i s values (0.4-0.59). The degree of v a r i a b i l i t y i n terms of the mean g r a i n s i z e , 4.39 to 6.54 0 (2.15 0) i s of a s i m i l a r order to the temporal v a r i a b i l i t y observed i n cores C2 (1.96 <f>), F1 (2.14 <t>) and 11 (2.77 0), ex c l u d i n g the t i l l and o x i d i z e d sand u n i t s . The same i s true for the s o r t i n g of the sediments: s p a t i a l v a r i a b i l i t y 1.65 0, compared with temporal v a r i a b i l i t y of 1.11 0 f o r C2, 0.44 0 f o r 68 F i g u r e 5 . 7 T e x t u r a l c h a r a c t e r i s t i c s o f the s u r f a c e sediments o f G a l l i e Pond: (a) Mean s i z e (b) S t a n d a r d d e v i a t i o n b) 6 9 Figure 5. 7 (continued) (c) Skewness (d) Kurtosis 0 5 10 m 1 ' • 70 F1 and 0.87 <f> f o r I 1 . Comparison of the t e x t u r a l c h a r a c t e r i s t i c s of the r e p r e s e n t a t i v e s o i l p r o f i l e s (Appendix I) of the Goat Meadows watershed (Table 5.4, F i g u r e 5.5) with those of the lake sediments i l l u s t r a t e s marked d i s c r e p a n c i e s . The sand f r a c t i o n c o n s t i t u t e s 60-90% of the catchment s o i l samples. The t e r r e s t r i a l samples are composed of f i n e to very f i n e g r a i n e d sand. The decrease of sand in the lake sediments o v e r l y i n g the t i l l and o x i d i z e d sands may be e x p l a i n e d i n terms of the compe-tency of flows t r a n s p o r t i n g sediments from the h i l l s l o p e s to the l a k e . The t e x t u r a l c h a r a c t e r i s t i c s of each of the 46 samples were p l o t t e d a g a i n s t one another, the two most i n f o r m a t i v e , mean versus skewness, and mean versus standard d e v i a t i o n , are presented i n F i g u r e 5.8. The s t r a t i g r a p h i c u n i t s are d i f f e r e n -t i a t e d i n order to determine any c o n s i s t e n c y i n trends f o r the d i f f e r e n t p e r i o d s they r e p r e s e n t . There i s c o n s i d e r a b l e s c a t t e r i n the r e l a t i o n s h i p s , both w i t h i n and between the d i f f e r e n t s t r a t i g r a p h i c u n i t s . Skewness may be used to d e f i n e d i f f e r e n t g r a i n s i z e mixtures (Figure 5.8 b), p o s i t i v e skewness d e f i n e s a predominantly coarse s i l t p o p u l a t i o n , while negative skewness a medium to f i n e s i l t p o p u l a t i o n . A l l of the u n i t s , with the e x c e p t i o n of the t i l l and ash h o r i z o n s , d i f f e r e n t i a t e d on the graphs by dashed l i n e s , e x h i b i t a somewhat s i m i l a r p a t t e r n i n d i c a t i n g a s i m i l a r e r o s i o n a l and d e p o s i t i o n a l regime to that of today, with 71 Table 5.4 P a r t i c l e s i z e c h a r a c t e r i s t i c s of the s o i l s of the Goat Meadows watershed S o i l Horizon Gravel Sand S i l t C l a y Mz ai Ski KG' (%) (0) (0) 83-6- 1 Ae 0.4 68. 1 30. 1 1 .4 2.75 2.44 0.08 0.4 Bh 0.4 83.0 16. 1 0.6 2.18 2.16 0.23 0.49 Bf j 0.5 86.5 12.3 0.7 1 .80 1 .96 0.16 0.5 BC 3.9 83.5 11.9 0.7 1 .73 2.01 0.11 0.46 83-2 Ah 1 .0 90.2 8.2 0.6 1 .76 1 .87 0.17 0.5 Bm 5.2 79.8 14.3 0.6 1 .95 2.06 0.03 0.49 Bmb 5.1 81.3 11.8 2.8 1 .89 1 .97 0.09 0.48 C 4.2 83. 1 11.1 1 .7 2.39 2.02 -0.30 0.53 83-6- 2 Ah 0.8 74.4 23.7 1 . 1 2.58 2.48 0.19 0.46 Bm 4.9 73.9 20.2 1 .0 2.64 2.31 0.08 0.48 Bmb 5.9 71 .7 21.7 0.7 2.66 2.56 0.07 0.48 BC 5.1 82.8 11.0 1 .2 2.03 2.11 -0.12 0.5 Reg 3. 1 59. 1 34.5 3.3 3.36 2.79 0.0 0.45 Gley 2.3 61 .9 35.2 0.7 3.45 2.15 -0.02 0.45 N.B. S o i l i d e n t i f i c a t i o n s r e l a t e to Appendix I Organic m a t e r i a l removed p r i o r to t e x t u r a l d e t e r m i n a t i o n Only <2 mm f r a c t i o n a n a l y s e d f o r s t a t i s t i c s 72 Figure 5.8 Plots of mean sediment si z e : (a) Mean vs. standard deviation (b) Mean vs. skewness (0) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.6 0.4 0.2 Sk 0 -0.2 -0.4 -0.6 • A . o 0 A 0 • •O 0 o A O 0« A A • O A O A • Lacustrine s i l t s 0 Ash (Bridge River & Mazama) A Lacustrine s i l t s & organic matter « Peat • T i l l / O x i d i z e d sands 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 Mz (0) 73 f l u v i a l , a e o l i a n and mass wasting processes a l l of importance (Jones, 1982). Thus the t e x t u r a l c h a r a c t e r i s t i c s of the s e d i -ment represent the i n t e g r a t e d response to a number of processes o p e r a t i n g i n a low energy environment, hence they cannot be used to d i f f e r e n t i a t e any changes i n the e r o s i o n a l / d e p o s i t i o n a l processes i n the Goat Meadows watershed over the Holocene Epoch. 5.1.5 Mineralogy The r e s u l t s of the X-ray d i f f r a c t i o n a n a l y s e s of the nine s t r a t i g r a p h i c u n i t s of the master core, F1,.are presented i n Table 5.5. An i n d i c a t i o n of the r e l a t i v e abundance of the d i f f e r e n t c l a y m i n e r als w i t h i n each sample i s given through a q u a l i t a t i v e r a t i n g , 0,1,2,3 or 4, which r e l a t e s to the r e l a t i v e i n t e n s i t i e s of the peaks on the d i f f r a c t o g r a m s (Appendix V I ) . I t i s important to s t r e s s that these are e n t i r e l y q u a l i t a t i v e o b s e r v a t i o n s ; given the high n o i s e l e v e l on the t r a c e s and the r e l a t i v e l y low peaks, they should be i n t e r p r e t e d with some c a u t i o n . In a d d i t i o n , they p r o v i d e i n f o r m a t i o n only f o r the wi t h i n sample v a r i a t i o n s . The peak i n t e n s i t i e s from d i f f e r e n t s l i d e s cannot be compared because of p o s s i b l e d i f f e r e n c e s i n p r e p a r a t i o n , f o r example, o r i e n t a t i o n of the g r a i n s , t h i c k n e s s of the mounts, exact weight of c l a y sample X-rayed, evenness of spread and degree of h y d r a t i o n . K a o l i n i t e and two forms cf v e r m i c u l i t e are the c l a y m i n e r a ls which dominate the <2 urn f r a c t i o n . K a o l i n i t e i s i d e n t i f i e d by the c o l l a p s e of the 7 A peak on h e a t i n g to 550°C, 74 Table 5.5 R e l a t i v e abundance of c l a y m i n e rals i n < 2 nm f r a c t i o n i n the s t r a t i g r a p h i c h o r i z o n s of the master core S t r a t i g r a p h i c K a o l . V e r 1 . V e r 2 . Mica C h i . Qtz. Amph. P l a g . u n i t L a c u s t r i n e s i l t s 3 3 3 0 0 0 0 0 L a c u s t r i n e s i l t s 3 2 3 0 0 2 1 1 L a c u s t r i n e s i l t s / B r i d g e R i v e r ash 3 3 2 2 0 1 1 2 La c u s t r ine s i l t s / o r g a n i c matter 3 3 3 2 2 2 0 0 P e a t / L a c u s t r i n e s i l t s 4 3 3 2 2 2 0 0 Peat 3 3 3 2 2 2 0 0 Peat/Mazama 4 3 3 2 2 2 0 0 L a c u s t r i n e s i l t s / o r g a n i c matter 3 3 3 2 2 2 2 2 T i l l 4 3 3 3 2 2 1 2 N.B. K a o l = k a o l i n i t e ; V e r 1 = v e r m i c u l i t e ; V e r 2 = p o o r l y weathered v e r m i c u l i t e - m i c a / v e r m i c u l i t e i n t e r g r a d e ; C h i . = c h l o r i t e ; Qtz.=quartz; Amph.=amphibole; P l a g . = p l a g i o c l a s e 4=dominant; 3=abundant; 2=present; 1=trace; 0=not present 75 evident i n every sample, while v e r m i c u l i t e i s i n d i c a t e d by d e h y d r ation on heating from a 14 A peak when magnesium s a t u r a t e d , to a 10 A peak at K-550°C. There i s evidence for the occurence of a v e r m i c u l i t e - m i c a i n t e r g r a d e from the 14 A peak on the K s a t u r a t e d a i r d r i e d s l i d e . No enhancement of t h i s peak was evident on heating to 550°C, thus i t i s u n l i k e l y to be i n d i c a t i v e of c h l o r i t e . C h l o r i t e , i f present, as suggested by a minor peak of 4.7 A, i s present only i n small q u a n t i t i e s . I t i s probable t h a t the i n t e r g r a d e v e r m i c u l i t e , termed v e r 2 i n Table 5.5, i s a p o o r l y weathered form of v e r m i c u l i t e with i n t e r l a y e r aluminium which i n t e r f e r e s with the c o n t r a c t i o n and expansion of the l a t t i c e , thus c a u s i n g the r e g i s t r a t i o n of a 14 A spacing i n the a i r d r i e d s t a t e . There i s evidence i n four of the s t r a t i g r a p h i c u n i t s f o r f e l d s p a r , with strong r e f l e c t i o n s at 3.18-3.25 A. The p r e c i s e p o s i t i o n s of the peaks suggest that the f e l d s p a r s are p l a g i o c l a s e , i n c l u d i n g some c a l c i u m r i c h v a r i e t i e s , s i g n i f i e d by a peak at 3.15 A. I t i s probable that the s t r o n g quartz r e f l e c t i o n s at 3.35 A have masked the presence of any potassium f e l d s p a r s . Amphibole i s i n d i c a t e d by the e x i s t e n c e of an 8.4 A peak in many of the t r a c e s , however, i n no case i s i t l a r g e . The r e s u l t s i n d i c a t e a f a i r l y c o n s i s t e n t balance amongst the c l a y m i n e r a l s present, and t h e i r r e l a t i v e importance in each s t r a t i g r a p h i c u n i t over the p o s t g l a c i a l p e r i o d . For most of the Holocene k a o l i n i t e and v e r m i c u l i t e have dominated the mineralogy, with minor amounts of mica, c h l o r i t e , q u a r t z , 76 amphibole and p l a g i o c l a s e p r e s e n t . T h i s r e l a t i o n s h i p holds even i n those h o r i z o n s e n r i c h e d with Bridge River and Mazama v o l c a n i c ash, i n d i c a t i n g only l i m i t e d i n f l u x of weathered ash m a t e r i a l from the catchment. On the h i l l s l o p e s the ash h o r i z o n s have d i s t i n c t i v e s i g n a t u r e s i n the < 2 /im f r a c t i o n with a very high m o n t m o r i l l o n i t e content. Thus the c l a s t i c sediment f l u x e s in the catchment i n terms of source area are i n s t r o n g c o n t r a s t to the s o l u t e f l u x e s where the primary source of c a t i o n s i s the weathering of the v o l c a n i c ash ( G a l l i e , 1983). There would appear to be c e r t a i n d i f f e r e n c e s i n the mineralogy of the uppermost sediments as i n d i c a t e d by the absence of c h l o r i t e and mica, and the recent decrease i n the q u a r t z , amphibole and p l a g i o c l a s e c o n t e n t s . T h i s i s most pronounced in the uppermost, l e s s w e l l c o n s o l i d a t e d l a c u s t r i n e s i l t s . There w i l l be a f u l l e r d i s c u s s i o n of these trends i n the context of the i d e n t i f i c a t i o n of sediment source areas i n s e c t i o n 5.3. 5.1.6 E x t r a c t a b l e Iron and Aluminium D i t h i o n i t e - e x t r a c t a b l e Fe and A l was determined as an index of the r e l a t i v e weathering of the sediments ( B i r k e l a n d , et a l . , 1979; Arduino, 1984). F i g u r e 5.9 p r e s e n t s the r e s u l t s of the a n a l y s e s , i n which the v a l u e s are expressed as % of sediment. There i s a d i s t i n c t i n c r e a s e i n the content i n the most recent sediments. The i r o n content i n c r e a s e s c o n s i s t e n t l y over time, although the aluminium content shows v a r i a t i o n s from t h i s t r e n d , r e l a t i n g p r i m a r i l y to the lowermost l a c u s t r i n e s i l t 77 F i g u r e 5.9 E x t r a c t a b l e i r o n and aluminium c o n t e n t o f the s t r a t i g r a p h i c u n i t s o f the master c o r e 78 u n i t e n r i c h e d with organic matter and Mazama ash d e p o s i t i o n . These r e s u l t s may be i n t e r p r e t e d as i n d i c a t i v e of more weathered sediments accumulating in G a l l i e Pond in the recent p e r i o d , suggesting a pedogenic source fo r the m a t e r i a l i n the l a t t e r part of the Holocene. These i n f e r e n c e s are f u r t h e r s u b s t a n t i a t e d by the r e s u l t s of t o t a l element content (5.1.7) and the mineralogy of the sediments (5.1.5 and 5.3.1). 5.1.7 Chemical p r o p e r t i e s of the sediments The pH of the lake sediments was determined i n 1:2 0.01 M C a C l 2 , which more a c c u r a t e l y r e p r e s e n t s the sediment pH under f i e l d c o n d i t i o n s ( S c h o f i e l d and T a y l o r , 1955). Readings taken vary between 4.5 and 5.3, with the lowest v a l u e s i n the peaty h o r i z o n s . However, there was no systematic t r e n d with depth, nor a c r o s s the l a k e . The t o t a l element content of the d i f f e r e n t s t r a t i g r a p h i c u n i t s of the master core was determined. Previous r e s e a r c h has suggested that i n c r e a s e s i n the inputs of c a t i o n s such as sodium, potassium and magnesium i n t o lake sediments may be i n t e r p r e t e d as i n d i c a t o r s of e r o s i o n a l a c t i v i t y w i t h i n a lake catchment ( s e c t i o n 2.2.3). The major and t r a c e element content, expressed as % sediment, of the d i f f e r e n t s t r a t i g r a p h i c u n i t s are presented i n Appendix V and F i g u r e 5.10. The r e s u l t s are r e p o r t e d f o r only 11 of the 23 elements an a l y s e d because the estimates f o r the other 12 elements were found to be u n s t a b l e , and there was 79 F i g u r e 5.10 T o t a l element c o n t e n t o f t h e d i f f e r e n t s t r a t i g r a p h i c h o r i z o n s o f the master c o r e (% o f sediment) 80 g r e a t e r than +10% v a r i a t i o n on some of the r e s u l t s determined f o r standards. In g e n e r a l , the most recent lake sediments and the s i l t s u n d e r l y i n g the Bridge R i v e r ash d e p o s i t e x h i b i t the highest element content. T h i s t r e n d i s most pronounced i n the cases of A l , Ca, Fe, Mn and S i . Secondary peaks occur i n the u n d e r l y i n g t i l l and the Mazama ash d e p o s i t . The Mazama ash i s e s p e c i a l l y e n r i c h e d with Mg, while the Bridge River ash has the lowest content of a l l elements with the exce p t i o n of Na and P. T h i s p a t t e r n of i n c r e a s i n g content i n the l a t t e r part of the Holocene i s o p posite to that found i n many s t u d i e s ( c . f . Hutchinson, 1957) which document a decrease over the p o s t g l a c i a l . Such decreases have been a t t r i b u t e d to p r o g r e s s i v e l e a c h i n g of s o i l s w i t h i n the watershed under study which a f f e c t the c h a r a c t e r i s t i c s of the sediment d e p o s i t e d i n the l a k e . There would appear to be somewhat s i m i l a r trends i n the f l u c t u a t i o n s of the d i f f e r e n t element c o n c e n t r a t i o n s with depth. In order to assess the c o n s i s t e n c y of these r e l a t i o n -s h i p s the c o r r e l a t i o n c o e f f i c e n t (r) was determined between each p a i r of elements (Table 5.6). The s i g n a t u r e s of the ash hor i z o n s are so strong that they are l i k e l y to b i a s the nature of the r e l a t i o n s h i p s f o r the remainder of the sedimentary column. Hence these v a l u e s were omitted from the c a l c u l a t i o n s . There would appear to be c o n s i d e r a b l e v a r i a b i l i t y i n the nature of the r e l a t i o n s h i p s , for example, A l and Ca are s i g n i f i c a n t l y p o s i t i v e l y c o r r e l a t e d with Ba, Fe, Mn, S i , Sr and T i ; Na i s n e g a t i v e l y c o r r e l a t e d with a l l the elements but not at a 81 Table 5.6 C o r r e l a t i o n c o e f f i c e n t s f o r each p a i r of elements A l Ba Ca Fe Mg Mn Na P S i Sr T i A l 1.0 Ba 0.88* 1 .0 Ca 0.93* 0.71* 1 .0 Fe 0.80* 0.50 0.96* 1 .0 Mg 0.29 0.14 0.46 0.47 1.0 Mn 0.67 0.32 0.85* 0.92* 0.61 1 .0 Na -0.18 • -0.31 -0.05 0.05 0.21 0.06 1 . 0 P -0.51 • -0.61 -0.34 -0.19 -0.20- 0.49 0. 93* 1 .0 S i 0.93* 0.86* 0.81* 0.59 0.20 0.49 -0. 17 -0 .50 1 .0 Sr 0..70* 0.67 0.59 0.35 0.14 0.17 0. 09 -0 .33 0 .85*1 .0 T i 0.82* 0.55 0.97* 0.98* 0.47 0.98* 0. 05 -0 .20 0 .64 0 .40 N.B. * i n d i c a t e s s i g n i f i c a n c e at p=0.05 82 s i g n i f i c a n t l e v e l ; and Ba e x h i b i t s both p o s i t v e and negative r e l a t i o n s h i p s with d i f f e r e n t elements. I t would appear that although no one element can be used as a s u r r o g a t e f o r the v a r i a b i l i t y of a l l others ( c . f . Edwards and Rowntree, 1980), three subgroups of s t r o n g l y c o r r e l a t e d elements: P - Na; Fe -Mn - Ca - T i ; and, S i - A l - Sr may be i d e n t i f i e d . I t i s proposed that these groups r e l a t e to the weathering products d e r i v e d and t r a n s l o c a t e d from the ash l a y e r s , the weathering of the dark m i n e r a l s , and weathering of the f e l d s p a r s r e s p e c t i v e l y . The v a l u e s f o r t o t a l Fe and A l content e x h i b i t a s i m i l a r t r end to those of the d i t h i o n i t e e x t r a c t i o n procedure ( s e c t i o n 5.1.6) suggesting that the i n c r e a s e i n the chemical content of the most recent sediments can be i n t e r p r e t e d as an i n c r e a s e d input of weathered m a t e r i a l from which the s o l u t e s have not been l o s t . The high element content of the sediments d e p o s i t e d in the p e r i o d s immediately preceding Bridge R i v e r ash d e p o s i -t i o n and the p e r i o d subsequent to that may be e x p l a i n e d i n terms of t r a n s l o c a t i o n of elements from the ash e n r i c h e d l a y e r by d i f f u s i o n processes through the sedimentary column, and the input of the weathering products from the ash l a y e r from the catchment. The low content i n the peaty h o r i z o n s may i n d i c a t e e i t h e r an input of sediment with low adsorbed chemical content or a l t e r n a t i v e l y may be a t t r i b u t e d to the markedly d i f f e r e n t h y d r o l o g i c a l regime of that time p e r i o d . During the hypsithermal i n t e r v a l before 6300 years B.P. the lake had d r i e d up, and p e r c o l a t i n g water through the peaty d e p o s i t s combined 83 with the a c i d i f y i n g i n f l u e n c e of the peat may have been respon-s i b l e f o r m o b i l i s a t i o n / r e m o v a l of exchangeable elements. Thus in s i t u l e a c h i n g would have been the cause of the low chemical content of the sediments. 5.1.8 Organic carbon, n i t r o g e n The changes of organic carbon and n i t r o g e n , and the r a t i o of one to the other, the C/N q u o t i e n t , are presented f o r the master core i n F i g u r e 5.2. Organic carbon e x h i b i t s a st r o n g c o v a r i a n c e with the organic matter content (Figure 5.2). The organic carbon content ranges from 0.8 to 8.8% with peak values i n the peaty h o r i z o n s and those e n r i c h e d with the organic matter, with the lowest values i n the two ash and t i l l h o r i z o n s . The t o t a l n i t r o g e n content e x h i b i t s a somewhat s i m i l a r t r e n d , although there i s l e s s of a decrease i n the peat u n d e r l y i n g the Mazama ash h o r i z o n . The g r e a t e s t values occur i n the lowermost l a c u s t r i n e s i l t s e n r i c h e d with organic matter, content ranging 0.08 to 0.66%. In g e n e r a l , the carbon content of the organic matter i s at l e a s t an order of magnitude g r e a t e r than n i t r o g e n . The C/N q u o t i e n t may be used to i n t e r p r e t a l l o c h t h o n o u s and autochthonous sources of the organic matter (Hutchinson, 1957). In general a l l o c h t h o n o u s organic matter, d e r i v e d from peaty m a t e r i a l e i t h e r i n the lake sediments or from marginal bogs adjacent to the lake or i n f l u e n t streams, has a C:N r a t i o of between 40 and 50:1, whereas autochthonous m a t e r i a l produced by the decomposition of plankton w i t h i n the lake has a C:N r a t i o approximately 12:1 (Wetzel, 1983). The values f o r G a l l i e 84 Pond vary between 11 and 35, with peak r a t i o s i n the peat and t i l l , and lowest values i n the two ash h o r i z o n s . The v a l u e s i n the peat and t i l l are r e l a t i v e l y h i g h ( c . f . B i r g e and Juday, 1934) i n d i c a t i n g that the m a t e r i a l has been d e r i v e d from peat p r o d u c t i o n i n a p e r i o d when the lake d r i e d up. The organic matter i n the ash h o r i z o n s , which i s a low percentage ( s e c t i o n 5.1.3), i s d e r i v e d p r i m a r i l y from the decomposition of plankton. In the remaining h o r i z o n s both sources are probably of importance. 5.2 Temporal v a r i a b i l i t y i n sediment y i e l d 5.2.1 E s t i m a t i o n of r a t e s of accumulation The t o t a l volume of sediment accumulated i n G a l l i e Pond was determined through the combination of the c o r e , probe and survey data. The cores were c r o s s c o r r e l a t e d on the b a s i s of s t r a t i g r a p h y (Appendix IV) to produce a s e r i e s of isopach maps (Fig u r e 5.11) which enables the v a r i a t i o n of i n f l u x through time to be estimated (Table 5.7). The v o l u m e t r i c data were converted to a mass of c l a s t i c sediment i n f l u x u s i n g the minerogenic bulk d e n s i t y data r e p o r t e d i n Table 5.1. The e r r o r bars around the estimates of accumulated mass i n Table 5.7 (+2o) r e l a t e to the v a r i a b i l i t y of the bulk d e n s i t y data w i t h i n each s t r a t i g r a p h i c u n i t (Table 5.1) d i s c u s s e d i n s e c t i o n 5.1.2. C h r o n o l o g i c a l c o n t r o l f o r the r a t e of i n f l u x c a l c u l a t i o n s i s p r o v i d e d by the two ash l a y e r s and radiocarbon dates (Appendix I I I ) . Further e r r o r s are a s s o c i a t e d with these, and 85 igure 5.11 Isopach maps of sediment accumulation in G a l l i e Pond for four periods: (a) Depth of sediment to top of t i l l (b) Depth of surface on which Mazama ash deposited 86 F i g u r e 5.11 (continued) (c) Depth t o t o p o f peat (d) Depth t o s u r f a c e on which B r i d g e R i v e r ash d e p o s i t e d 0 ,5 1,0 m • C o r i n g l o c a t i o n C ontour i n t e r v a l i n cm 87 Table 5.7 Sedimentation i n G a l l i e Pond S t r a t i g . Date Volume Mass u n i t (yr.B.P.) (m 3)(m 3/yr) (kg) (kg/m 2) (kg/m 2/yr) L a c u s t r i n e s i l t s 6. 7 5829+1632 16. 3 + 4 .6 > L a c u s t r i n e s i l t s 8. 9 0 .008 7832+2506 21 . 9 + 7 .0 \ 0.022 + 0 .007 / [0.01 - 0.0 L a c u s t r i n e s i l t s / B r i d g e River ash 3. 6 4860+1652 13. 6 + 4 .6 > 2400 L a c u s t r i n e s i l t s / o r g a n i c matter 20. 2 0 .005 8484+1527 23. 7 + 4 .3 0.006+0 .001 6340 [0.004 - 0. Peat/ l a c u s t r i n e s i l t s 9. 7 2813+1181 7. 9 + 3 .3 0 .04 I 0.05+0. 02 Peat/ / [0.01 - 0.0 Mazama ash 2. 2 1606+514 4. 5+1 .4 J 6600 Peat 38. 6 8492+3057 23. 8 + 8 L a c u s t r i n e 0 .01 > 0.007+0 .002 s i l t s / o r g a n i c [0.004 - 0. matter 6. 7 2144+429 6. 0 + 1 .2 > 1 0500 T o t a l 96.6 Mean 0.0092 0.0112+0.003 N.B. Volume - T o t a l volume i n c l u d i n g organic matter Mass - Mass of c l a s t i c sediment E r r o r bars +2 standard d e v i a t i o n [] Minimum - maximum range (see tex t ) 88 are i n c o r p o r a t e d i n the f i n a l column of Table 5.7. The range presented w i t h i n the square b r a c k e t s represents the extreme v a l u e s of i n f l u x p o s s i b l e t a k i n g i n t o account v a r i a b i l i t y of bulk d e n s i t y and maximum e r r o r s i n the dates. 5.2.2 The sampling technique In order to gain an impression of the p o s s i b l e e r r o r s i n v o l v e d when e s t i m a t i n g volumes of t o t a l sediment i n f l u x from only one core i n the l a k e , t o t a l sediment i n f l u x has been c a l c u l a t e d using a number of methods (Table 5.8): f i r s t l y , u s i n g the data c o l l e c t e d from the 2 x 2 m g r i d to estimate volumes using d i f f e r e n t g r i d s i z e s and o f f s e t s ; and, secondly, to c a l c u l a t e sediment volumes from assumptions about the shape of accumulated sediment. The g r i d e s t i m a t i o n s a l l g i v e an underestimate when compared to the values o b t a i n e d from the 2 x 2 m g r i d , while the shape r e c o n s t r u c t i o n s p r o v i d e an overestimate. T h i s i s a consequence of the shallow e l l i p t i c a l nature of the sediments i n the l a k e , with no r e g u l a r p a t t e r n of accumulation about a s i n g l e c e n t r e of d e p o s i t i o n . The t r e n d of i n c r e a s i n g b i a s with widening g r i d may be a t t r i b u t e d to the a n i s o t r o p i c c o n d i t i o n s of sediment accumulation i n G a l l i e Pond ( F i g u r e 5.11 a ) . I t would not be expected to occur i n s t r a i g h t s i d e d f l a t - b e d d e d l a k e s . The i n c r e a s i n g s i z e of g r i d i n c r e a s e s the p r o b a b i l i t y of mis s i n g the major peak of accumulation towards the western end of the G a l l i e Pond. To o b t a i n an ac c u r a t e estimate of the accumulated sediment the g r i d should be t i g h t e r than the l e n g t h s c a l e of 89 Table 5.8 Comparison of d i f f e r e n t methods f o r determining sediment volumes i n G a l l i e Pond Method T o t a l volume of % d i f f e r e n c e from f i n e s (m 3) 2 x 2 m g r i d G r i d : 2 x 2 m 96.65 4 x 4 m 75.04 -22.36 (4 o f f s e t s ) 78.29 -18.99 76.95 -20.35 78.50 -18.78 8 x 8 m 51.78 -46.43 (2 o f f s e t s ) 53.45 -44.70 Shape: C i r c u l a r cone 392.93 243.43 H a l f -e l l i p s o i d 169.28 75.15 P a r a b o l o i d of r e v o l u t i o n 361.79 274.33 N.B. Diameter of the major d e p o s i t i o n a l area to the west of the lake 12 m; focus of accumulation w i t h i n t h i s 5 m 90 any c h a r a c t e r i s t i c peaks i n accumulation, hence of c h a r a c t e r i s -t i c bottom roughness l e n g t h s . In the s p e c i f i c example of G a l l i e Pond, the diameter of the major d e p o s i t i o n a l area to the west of the lake i s 12 m; however, the diameter of the major c e n t r e of accumulation w i t h i n t h i s i s 5 m (Figure 5.11 a ) . Hence the 4 and 8 m g r i d s i n a l l p r o b a b i l i t y missed the g r e a t e s t depth of accumulation, while the 2 m g r i d produced two readings of depth w i t h i n t h i s area g r e a t l y enhancing the accuracy of the estimate of accumulated sediment volume. I t i s not p o s s i b l e to estimate the e r r o r s a s s o c i a t e d with the 2 x 2 m g r i d and probe data which are i n c o r p o r a t e d i n the i n f l u x r e s u l t s used as a standard. 5.2.3 I n t e r p r e t a t i o n of r e s u l t s The isopach maps i n F i g u r e 5.11 i l l u s t r a t e t h a t the the g r e a t e s t depth of sediment accumulation has occurred near the i n l e t of Mosquito Creek, with secondary c e n t r e s i n the v i c i n i t y of Hummingbird Creek ( F i g u r e 5.11 a) and the c e n t r e of the l a k e ( F i g u r e 5.11 b ) . Sediment accumulation i n G a l l i e Pond does not conform to a simple c o n c e n t r i c model of sediment f o c u s i n g . There i s a f a i r l y c o n s i s t e n t p a t t e r n of accumulation over time which e x h i b i t s a s t r o n g correspondance with contemporary water depth ( F i g u r e 3.4), g r e a t e s t accumulation under the g r e a t e s t depth of water. However, the importance of the secondary centre of accumulation to the f a r east of the lake would appear to have d e c l i n e d i n importance over time 91 (compare F i g u r e 5.11 a with c and d ) , probably a consequence of a d e p r e s s i o n i n the o r i g i n a l t i l l morphology being f i l l e d i n . T h i s i n d i c a t e s the r e l a t i v e importance of the Hummingbird sub-catchment, at l e a s t i n the e a r l y p o s t g l a c i a l p e r i o d , i n terms of the input of f i n e sediment d e r i v e d from f e a t u r e s such as d e b r i s l o b e s , i n c o n t r a s t to the Mosquito catchment, where the s u r f i c i a l m a t e r i a l s c o n s i s t of much co a r s e r t a l u s . D e s p i t e the obvious l i m i t a t i o n s of the lake sedimentation approach i n the d e t e r m i n a t i o n of i n f l u x r a t e s i n terms of the r e s o l u t i o n and e r r o r s inherent i n the methodology, the v a l u e s of i n f l u x presented i n Table 5.7 o f f e r some i n d i c a t i o n of the v a r i a b i l i t y of accumulation over time. The r a t e s of accumulation, i n v o l u m e t r i c terms, were g r e a t e s t d u r i n g the e a r l y p o s t g l a c i a l and hypsithermal i n t e r v a l s , and lowest i n the p e r i o d s preceding and subsequent to t h i s . A p o s s i b l e non-p h y s i c a l e x p l a n a t i o n f o r which i s t h a t t h i s i s the s h o r t e s t time p e r i o d c o n s i d e r e d (6000-6340 years B.P.), consequently the e r r o r s a s s o c i a t e d with the r a d i o c a r b o n (6340 +150) and ash (Table 111. 1 ) dates have the g r e a t e s t e f f e c t ( l a s t column i n Table 5.7). When the lower l i m i t of the range i s c o n s i d e r e d (0.01 kg/m 2/yr) the i n f l u x of c l a s t i c sediment i n the l a t e h y p s i t h e r m a l i n t e r v a l i s of a s i m i l a r order to that i n the most recent p e r i o d . The same p a t t e r n i s evident even i f account i s made of the maximum p o s s i b l e c o n t r i b u t i o n s of Mazama and Bridge R i v e r ash (2.2 and 3.6 m3 r e s p e c t i v e l y ) . The p a t t e r n f o r i n f l u x of c l a s t i c sediment i s somewhat s i m i l a r , the major d i f f e r e n c e i s 92 in terms of the g r e a t e r r e l a t i v e importance of the most recent p e r i o d , above average i n terms of the mass of i n f l u x , but below average i n v o l u m e t r i c terms, a consequence of the low organic content and high minerogenic bulk d e n s i t y of the sediments (sect ion 5.1.2). The c l a s t i c sediment i n f l u x data to G a l l i e Pond can be converted to sediment y i e l d f o r the Goat meadows watershed (Table 5.9) to enable comparison with contemporary r a t e s documented by Jones (1982) (Table 5.10) and r e g i o n a l data (Table 5.11). In the case of sediment y i e l d i n t e r e s t i s r e s t r i c t e d to that m a t e r i a l d e r i v e d from the Goat Meadows watershed. Hence, the Bridge R i v e r ash, which i s known to be formed p r i m a r i l y from ash f a l l , was d e l e t e d from the assessment of l o c a l sediment y i e l d s , r e s u l t i n g i n an e r o s i o n r a t e of 2.3 x 10"" r a t h e r than 3.7 x 10"" kg/m 2/yr f o r the post 2400 years B.P. time p e r i o d . The p a t t e r n i s s i m i l a r to that determined f o r the i n f l u x v a l u e s of c l a s t i c sediment, the highest r a t e s being observed d u r i n g the h ypsithermal i n t e r v a l (7 x 10"" +2.7 x 10~"), and the lowest values i n the p e r i o d 6340 to 2400 years B.P. (8.8 x 10" 5 +1.6 x 1 0 ~ 5 ) . High values i n the l a t e hypsithermal i n t e r v a l (6600 - 6340 years B.P.) are i n p a r t a consequence of the d i r e c t input of Mazama ash d u r i n g t h i s p e r i o d . However, i t i s d i f f i c u l t to determine the exact input of such m a t e r i a l from d i r e c t ash f a l l because the Mazama ash h o r i z o n i s d i s c o n t i n u o u s through p a r t s of the l a k e , an i n d i c a t i o n of some reworking and 93 Table 5.9 Sediment y i e l d from the Goat Meadows watershed S t r a t i g r a p h i c Date E r o s i o n r a t e u n i t ( y r s . B.P.) (kg/m 2) E r o s i o n r a t e (kg/m 2/yr) L a c u s t r i n e s i l t s L a c u s t r i n e s i l t s L a c u s t r i n e s i I t s / o r g a n i c matter Peat/ L a c u s t r i n e s i l t s Peat/Mazama ash Peat L a c u s t r i n e s i l t s / o r g a n i c matter 2400 6340 6600 0.24 +0.06 0.32 +0.10 0.35 +0.06 0.12 +0.05 0.07 +0.02 0.35 +0.13 0.09 +0.02 2.3+0.67x10"" [1.5-3.1x10""] 0.88+0.16x10"" [0.69-0.12x10""] 7.0+2.7x10"" [1.3-13x10""] 1.14+0.37x10"" [0.59-2.0x10""] 10500 Mean 1.47+0.42x10"" [1.0-1.98x10""] N.B. Area of the Goat Meadows watershed 0.024 km2 E r r o r bars +2 standard d e v i a t i o n [] Minimum - maximum range (see t e x t ) 94 Table 5.10 Contemporary sediment budget f o r the Goat Meadows watershed (from data i n Jones, 1982) Process Rate of t r a n s f e r (kg/m 2/yr) Animals 0.3 - 3 x 10"" A e o l i a n (summer) 8 x 10"" Snowpack 4 - 40 x 10"' Splash 3 - 9 x 1 0 " " T o t a l 15 - 60 x 10"" Table 5.11 Regional r a t e s of sediment y i e l d (from Slaymaker, 1977) Region Basin area (km 2) Y i e l d (kg/m 2/yr) Coast Mts: C e n t r a l 2.4 M i l l e r Creek 21.6 B r i t i s h Columbia: L i l l o o e t 3800 Fr a s e r 200,000 0.0053 0.034 1 .097 0.114 95 input from secondary watershed sources. T h i s r a i s e s the is s u e as to whether the Mazama ash i s l o c a t e d at i t s c h r o n o l o g i c a l l y c o r r e c t p o s i t i o n i n the s t r a t i g r a p h i c column. I f there had been much reworking on the h i l l s l o p e s and a delayed input the s e d i -mentation and y i e l d r a t e s c a l c u l a t e d i n t h i s study would be a r t i f i c i a l l y low, a s i t u a t i o n that i s u n l i k e l y to be the case as the y i e l d v a l u e s f o r t h i s p e r i o d are the h i g h e s t documented over the Holocene Epoch. Another p o s s i b i l i t y i s that the ash once d e p o s i t e d i n the peaty environment of G a l l i e Pond at that time f i l t e r e d down through the accumulating sediments to form a l a y e r some cm below the s u r f a c e (documented i n W i l l i a m s Lake, Washington by Anderson et a l . (1984)) a r t i f i c a l l y i n f l a t i n g the r e s u l t s c a l c u l a t e d here. However, both of these s c e n a r i o s have been d i s m i s s e d because the Mazama ash d e p o s i t i s r e l a t i v e l y coherent and where present there i s no evidence f o r i n t e r m i x i n g or contamination from other sources. The y i e l d data f o r the Goat Meadows watershed as d e t e r -mined from the accumulation of lake sediments i s approximately one order of magnitude lower than the contemporary y i e l d e stimated by Jones (1982). Jones determined sediment y i e l d by s p a t i a l l y i n t e g r a t i n g a number of i n d i v i d u a l p l o t s t u d i e s f o r the d i f f e r e n t sediment t r a n s f e r processes assessed to be important. I t i s apparent from the lake data that sediment t r a n s f e r s from a e o l i a n sources are a p p a r e n t l y exaggerated, as i s the animal c o n t r i b u t i o n which i s h i g h l y s i t e s p e c i f i c . Given the slow t r a n s f e r of sediment through the system and the e x i s t e n c e of many t e r r e s t r i a l storage u n i t s , f o r example d e b r i s lobes and 96 the s o i l mantle, i t i s not s u r p r i s i n g that the r a t e s of sediment t r a n s f e r s summed f o r the h i l l s l o p e s of the b a s i n do not equal the l o s s of sediment i n t o the l a k e . The e r o s i o n values f o r the Goat Meadows watershed are one and two orders of magnitude lower than those of the C e n t r a l Coast Mountains and M i l l e r Creek r e s p e c t i v e l y (Table 5.11). A p o t e n t i a l e x p l a n a t i o n f o r the d i s c r e p a n c i e s i n y i e l d data i s that the study watershed i s a small subalpine drainage basin which has not experienced the e f f e c t s of l a r g e s c a l e f l u v i a l channel and bank e r o s i o n , l a r g e s c a l e mass movements, or a n t h r o p o g e n i c a l l y induced landuse changes. These f a c t o r s and processes are r e s p o n s i b l e f o r high sediment y i e l d s from the l a r g e r watersheds of the Coast Mountains and southern B r i t i s h Columbia (Slaymaker and G i l b e r t , 1972; G i l b e r t , 1973; Hart, 1979). The e x p l a n a t i o n of l i m i t e d f l u v i a l a c t i v i t y has been invoked p r e v i o u s l y i n the a l p i n e environment by Caine (1974) and Slaymaker (1977). 5.2.4 The source of the sediment It i s important to determine from where the volume of f i n e sediment i n the lake has been d e r i v e d ; whether i t i s s o i l l o s s from the h i l l s l o p e s d e l i v e r e d by s u r f a c e p r o c e s s e s , a e o l i a n r e d i s t r i b u t i o n of s u r f i c a l m a t e r i a l , or the product of e r o s i o n from the lake's t i l l s h e l f and banks. T h i s i s s u e w i l l be d i s c u s s e d both in terms of v o l u m e t r i c c o n s i d e r a t i o n s i n t h i s s e c t i o n , and through sedimentary c h a r a c t e r i s t i c s and source 97 area i d e n t i f i c a t i o n i n s e c t i o n 5.3. It i s p o s s i b l e to estimate the magnitude of the net c o n t r i b u t i o n of a e o l i a n d e p o s i t i o n and the processes of h i l l s l o p e r e d i s t r i b u t i o n over the p o s t g l a c i a l p e r i o d from the accumulation of a e o l i a n m a t e r i a l as a l o e s s capping o v e r l y i n g the t i l l i n the m a j o r i t y of the watershed's s o i l p r o f i l e s (Figure 3.7). A reasonable estimate of accumulation, based on observa-t i o n s d u r i n g f i e l d w o r k , i s 20 cm (depths range 10-40 cm). However, a c c o r d i n g to Jones (1982), G a l l i e (1983) and the p r o f i l e d e s c r i p t i o n s made i n t h i s study, approximately 33% of t h i s depth i s ash, and 25-30% of the <2 mm f r a c t i o n i s organic matter. The s o i l matrix a l s o c o n s i s t s of 10% g r a v e l and 30% boulders, hence only about 30% or 6 cm depth can be a s c r i b e d to wind d e p o s i t i o n . An average bulk d e n s i t y of 1100 kg/m3 (Jones, 1982), may be used to convert t h i s volume to an accumulation of 66 kg/m2 or an average of 0.0063 kg/m 2/yr f o r the Holocene Epoch. However, t h i s estimate i s s e n s i t i v e to the value s e l e c -ted f o r the bulk d e n s i t y : f o r example, 1300 kg/m3 r e s u l t s i n an accumulation of 0.0074 kg/m 2/yr, whereas 900 kg/m3 produces a r a t e 0.0051 kg/m 2/yr. The value of 0.0063 kg/m 2/yr i s one order of magnitude lower than the mean i n f l u x r a t e i n t o G a l l i e Pond (0.0112 +0.003 kg/m 2/yr) and i s almost i d e n t i c a l to those r a t e s determined f o r the p e r i o d s 10,500-6600, and 6340-2400 years B.P. In the p e r i o d 6600-6340 years B.P. and the post Bridge R i v e r p e r i o d i n f l u x has been of an order of magnitude g r e a t e r (0.05 and 0.022 kg/m 2/yr r e s p e c t i v e l y ) . 98 An a l t e r n a t i v e p o t e n t i a l source of sediment i s the t i l l s h e l f around the edge of the lake ( s e c t i o n 3.2). An approximate estimate of the volume of m a t e r i a l eroded from t h i s p a r t of the l a k e , based on survey, probe and s o i l p r o f i l e data, assuming there was once a continuous smooth slope i n t o the l a k e , i s 29.3 m3. If the estimate i s c o r r e c t i t may account f o r ca. 25% of the c l a s t i c sediment input i n t o the l a k e . T h i s area was p o t e n t i a l l y a major source of f i n e sediment i n p e r i o d s when the water l e v e l f e l l , f o r example d u r i n g the hypsithermal i n t e r v a l , or a l t e r n a t i v e l y d u r i n g p e r i o d s of i c e b u i l d up and more severe bank e r o s i o n . Other sediment t r a n s f e r processes of importance i n the Goat Meadows watershed, which are not q u a n t i f i a b l e i n terms of t h e i r c o n t r i b u t i o n to the sediments of G a l l i e Pond over the Holocene time p e r i o d , i n c l u d e the onward t r a n s f e r of a e o l i a n sediment by water, r i l l or s u r f a c e wash e r o s i o n over the d r a i n -age b a s i n , m a t e r i a l d e r i v e d from stream channel beds and banks, and m i c r o g e l i v a t i o n products washed o f f bedrock s u r f a c e s . The r e l a t i v e importance of these sources w i l l be assessed i n the next s e c t i o n through m i n e r a l o g i c a l evidence. 5.3 I d e n t i f i c a t i o n of sediment source areas 5.3.1 M i n e r a l o g i c a l evidence In a d d i t i o n to f u n c t i o n i n g as an a i d i n the c h a r a c t e r i s a t i o n of the l a c u s t r i n e sediments of G a l l i e Pond c l a y s i z e d p a r t i c l e mineralogy may p o t e n t i a l l y be used i n the 99 i d e n t i f i c a t i o n of dominant sediment source areas ( s e c t i o n 2.4.1). Throughout the basin there e x i s t many bedrock outcrops and unyegetated t a l u s s l o p e s , p o t e n t i a l l y a major source of c l a s t i c sediment. However, comparison of rock mineral abundances and lake sediment mineralogy r e v e a l s s e v e r a l d i s c r e p a n c i e s . The two major rock types are quartz d i o r i t e and quartz a c t i n o l i t e s c h i s t . The percentage m i n e r a l compositions of each of these are presented i n Table 5.12. Quartz, although a dominant component of both rock types, i s only present as a low percentage i n the lake sediments. However, t h i s i s probably a consequence of the s i z e f r a c t i o n analysed f o r X.R.D. Jones (1982) notes that D i o r i t i c Quartz i s found i n g r a i n s 0.05-0.5 mm i n diameter, w e l l in excess of the e x c l u s i o n of 2 urn f o r X.R.D. a n a l y s i s . Both l i t h o l o g i e s are q u i t e r i c h i n c h l o r i t e : however, t h i s m i neral i s present i n only small q u a n t i t e s i n the lake sediments, and has decreased with time i n d i c a t i n g that the bedrock outcrops do not provide the dominant d i r e c t sediment source i n the b a s i n , although they may have had a g r e a t e r r e l a t i v e importance i n the e a r l i e r p o s t g l a c i a l p e r i o d . A much gr e a t e r correspondence i n m i n e r a l o g i c a l composition i s e v i dent when the lake sediment r e s u l t s are compared with data f o r r e p r e s e n t a t i v e s o i l pedons of the Goat Meadows watershed, obtained from G a l l i e (1983) (Table 5.13). The s u r f a c e h o r i z o n s of the Sombric B r u n i s o l and the Regosol p r o f i l e s both i l l u s t r a t e a predominance of k a o l i n i t e and v e r m i c u l i t e . The apparent absence of smec t i t e s i n the lake 100 Table 5.12 P e t r o g r a p h i c d e s c r i p t i o n s of l i t h o l o g i e s (from G a l l i e , 1983) L i t h o l g y M i n e r a l % Composition Q u a r t z - a c t i n o l i t e -c h l o r i t e s c h i s t Quartz A c t i n o l i t e C h l o r i t e * Epidote D i o p s i t e Sphene B i o t i t e 60 21 1 3 3 1 1 1 Q u a r t z - d i o r i t e 30 20 1 5 1 5 10 3 N.B. * C h l o r i t e i s the weathering product of the amphiboles 101 Table 5.13 R e l a t i v e abundance of c l a y m i n e r a l s i n < 2 Mm f r a c t i o n s i n the h o r i z o n s of r e p r e s e n t a t i v e pedons (from G a l l i e , 1983) S o i l Parent Kao. Smc. Ver. M/V M/S C h i . Mic. P i g . Amp. Qtz. m a t e r i a l Humo-F e r r i c Podsol Ae A 1 4 0 Bfh L 2 1 4 Bf T 4 2 4 BC T 3 1 2 Sombric B r u n i s o l Ah L 3 0 3 Bm A 3 3 2 Bmb L 4 3 3 Bmb A 0 0 0 Bmb C,L 3 3 1 Regosol Ahj C,L,A 3 3 2 Bm C,L,A 3 3 2 G l e y s o l Cg C,F 3 3 1 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 0 2 0 0 1 0 2 0 3 2 2 2 1 0 0 2 1 0 1 1 0 0 2 1 3 0 1 0 0 3 1 0 1 1 0 0 0 0 1 0 0 0 0 3 1 0 1 1 1 0 2 2 2 0 1 0 0 2 2 0 0 0 0 0 3 2 1 0 2 N.B. A=volcanic ash; C=colluvium; F = f l u v i a l ; L=loess; T = t i l l K a o . = k o a l i n i t e ; Smc.=smectite; V e r . = v e r m i c u l i t e ; M/V, M/S m i c a - v e r m i c u l i t e , mica-smectite i n t e r g r a d e s ; C h i . = c h l o r i t e ; Mic.=mica; P i g . = p l a g i o c l a s e ; Amp.=amphibole; Qtz.=quartz. 4=dominant; 3=abundant; 2=trace; 1=present; 0=not present 1 02 sediments may p o s s i b l y be e x p l a i n e d i n terms of the degree of weathering of the v o l c a n i c g l a s s i n the l a c u s t r i n e and t e r r e s t r i a l environments i n the l a s t 2000 y e a r s . The s m e c t i t e s , in g e n e r a l , have been produced i n subsurface h o r i z o n s , the ash (the source area) subsequently being covered by a e o l i a n d e p o s i t s , and thus not d i r e c t l y a v a i l a b l e f o r e r o s i o n by overland flow. The s i m i l a r i t y i n the mineralogy of the lake sediments and t i l l (stratum 9), suggests that the dominant sources of sediments i n the basin i n c l u d e those unvegetated a c t i v e areas, with l i m i t e d pedogenic development, which are adjacent to and u n d e r l i e the b a s i n ' s two streams, and the t i l l s h e l f w i t h i n the lake ( s e c t i o n 3.2; s e c t i o n 5.2.4). These sources have been supplemented i n the post hypsithermal p e r i o d with the g r e a t e r input of pedogenic m a t e r i a l d e r i v e d from Regosolic and B r u n i s o l i c t e r r e s t r i a l s i t e s . Jones (1982), a f t e r a study of the mineralogy of a e o l i a n m a t e r i a l d e p o s i t e d i n the catchment (Table 5.14), suggested a r e g i o n a l source f o r windblown m a t e r i a l , as i t r e f l e c t s the r e g i o n a l q u a r t z d i o r i t e r a t h e r than the l o c a l Gambier Group rock composition. However, there would appear to be l i t t l e s i m i l a r i t y i n terms of the mineralogy of the m a t e r i a l c o l l e c t e d in that study and that d e p o s i t e d i n the l a k e , a somewhat s u r p r i s i n g r e s u l t given that the lake c o n s t i t u t e s the primary sedimentary sink i n the b a s i n . However, i t i s important to s t r e s s that Jones's c o n c l u s i o n s are based on a n a l y s i s of the < 63 /im f r a c t i o n , whereas t h i s study i s concerned with that 1 03 Table 5.14 R e l a t i v e abundance of minerals i n the < 63 vm f r a c t i o n of contemporary l o e s s near Goat Meadows in d e c r e a s i n g order (Jones, 1982) M i n e r a l R e l a t i v e abundance P l a g i o c l a s e Most abundant Mica K a o l i n i t e V e r m i c u l i t e C h l o r i t e O r t h o c l a s e Quartz Least abundant 1 04 f r a c t i o n < 2 nm. The i n f o r m a t i o n on mineralogy does not exclude the importance of l o c a l i s e d a e o l i a n r e d i s t r i b u t i o n from i n t r a b a s i n sources. 5.4 D i s c u s s i o n T h i s s e c t i o n w i l l i n t e g r a t e the r e s u l t s presented in s e c t i o n s 5.1, 5.2 and 5.3 i n order to provide a summary of the palaeogeomorphic processes of the Goat Meadows watershed, recorded i n the sediments of G a l l i e Pond, f o r each of four time p e r i o d s over the Holocene Epoch: 10,500 - 6600; 6600 - 6340; 6340 - 2400; and, 2400 years B.P. to the p r e s e n t . 5.4.1 10,500 - 6600 years B.P. The i n t e r v a l 10,500 - 6600 B.P. encompasses that time between d e g l a c i a t i o n and Mazama ash d e p o s i t i o n . In the Goat Meadows watershed the immediate p o s t g l a c i a l i n t e r v a l was c o l d and wet; however, the subsequent i n t e r v a l c a . 10,000 to 6500 B.P. corresponds to the p e r i o d of maximum temperatures and minimum p r e c i p i t a t i o n r e cognised i n lowland s i t e s as the xerothermic hypsithermal i n t e r v a l . Throughout t h i s p e r i o d the v e g e t a t i o n i n the watershed was c o n s i d e r a b l y more a r b o r e a l and winter snow-packs may have been reduced by as much as 50% ( s e c t i o n 3.9). The p e r i o d embraces three s t r a t i g r a p h i c u n i t s : o x i d i z e d coarse sands; l a c u s t r i n e s i l t s e n r i c h e d with fragments of p a r t l y decomposed organic matter; and, f i b r o u s p e a t s . These r e f l e c t a t r a n s i t i o n from i n i t i a l c o n d i t i o n s of f l o w i n g water substan-t i a t e d by diatom evidence (Rouse, pers. comm.), to the formation 105 of a shallow lake d u r i n g the e a r l y p o s t g l a c i a l , to a f a l l i n water l e v e l and the development of a peat bog durin g the e a r l y h y p s i t h e r m a l , a consequence of the changes i n p a l a e o c l i m a t e . These changes i n d i c a t e a p r o g r e s s i v e decrease i n the r e l a t i v e e r o s i o n a l energy i n the watershed. The c l a s t i c sediment d e p o s i t e d i n the l a c u s t r i n e s i l t and peat h o r i z o n s has mean s i z e 4.67 and 4.820; standard d e v i a t i o n s 1.79 and 1.490; and, skewness -0.15 and -0.32 r e s p e c t i v e l y . These i n d i c a t e the accumulation of p r o g r e s s i v e l y f i n e r , i n c r e a s i n g l y w e l l s o r t e d and f i n e r skewed sediments, suggesting an i n c r e a s e i n the r e l a t i v e importance of the f i n e s i l t f r a c t i o n , which may p o s s i b l y be a t t r i b u t e d to e i t h e r an i n c r e a s e d p r o d u c t i o n by weathering ( s u b s t a n t i a t e d i n pa r t by s o i l p r o f i l e data) or an in c r e a s e i n the r e l a t i v e importance of a e o l i a n r e d i s t r i b u t i o n of sediment as documented by A l l e y (1976) i n the Okanagan. However, the s t r a t i g r a p h y of the s o i l p r o f i l e s on the h i l l s l o p e s ( F igure 3.5) i n d i c a t e s that the Mazama ash i s l o c a t e d near the base of the p r o f i l e s and i s o v e r l a i n by s u b s t a n t i a l accumulations of a e o l i a n m a t e r i a l . T h i s suggests that most a e o l i a n a c t i v i t y w i t h i n the catchment has occur r e d i n the l a t t e r p a r t of the p o s t g l a c i a l , i n d i r e c t c o n t r a s t to the f i n d i n g s of A l l e y (1976). During t h i s p e r i o d e p i s o d i c high frequency events i n the Hummingbird subcatchment were r e s p o n s i b l e f o r i n t r o d u c i n g d e p o s i t s of coarse sand i n t o the ea s t e r n part of the lake ( e v i d e n t i n cores V1 and V2). In a d d i t i o n , the isopach maps of 1 06 sediment accumulation i n d i c a t e that the sediment c o n t r i b u t i o n from the Hummingbird subcatchment d u r i n g t h i s p e r i o d may have dominated, r e s u l t i n g i n the i n f i l l i n g of a d e p r e s s i o n i n the t i l l u n d e r l y i n g the east end of the l a k e . The mineralogy of the lake d e p o s i t s i s very s i m i l a r to that of the t i l l , r e f l e c t i n g the input of sediment from u n s t a b l e , p o o r l y vegetated areas i n the v i c i n i t y of both the pond and incoming streams. During the hypsithermal i n t e r v a l , when the v e g e t a t i o n cover became more e x t e n s i v e , i t i s probable that the dominant source of sediment was that d e r i v e d from the t i l l s h e l f , exposed by a f a l l i n Water l e v e l . The mineralogy of the peaty h o r i z o n s i s very s i m i l a r t o that of the t i l l , how-ever, there i s an absence of amphibole and p l a g i o c l a s e , which p o t e n t i a l l y may have been among the f i r s t m i n e r a ls to have been weathered out d u r i n g the warm c o n d i t i o n s . The C:N r a t i o s of 15 -20 f o r p e r i o d i n d i c a t e both an autochthonous and a l l o c h t h o n o u s o r i g i n f o r the o r g a n i c matter, although p r i m a r i l y the l a t t e r . The i n f l u x of sediment i n v o l u m e t r i c terms was 0.01 m 3/yr, the second h i g h e s t r a t e f o r the p o s t g l a c i a l p e r i o d , however, the c l a s t i c sediment i n f l u x 0.007 +0.002 kg/m 2/yr ranked t h i r d , below the mean. T h i s d i s c r e p a n c y i s a consequence of the high organic matter content and low bulk d e n s i t y of the sediments. There i s no evidence f o r the p a r a g l a c i a l sedimentation documented in lowland areas ( s e c t i o n 1.1). However, i t i s probable that i n the p e r i o d immediately f o l l o w i n g d e g l a c i a t i o n that the h i g h energy c o n d i t i o n s of f l o w i n g water through G a l l i e Pond, as evidenced by the o x i d i z e d sands ( s e c t i o n 5.1.1), were 1 07 r e s p o n s i b l e f o r the removal of g l a c i a l sediment from the water-shed. T h i s removal of sediment to lowland s i t e s was completed by c a . 10,000 years B.P. when c l a s t i c sediment d e p o s i t i o n began. I t i s probable that t h i s marked the development of r e l a t i v e l y s t a b l e environment with poor c o u p l i n g between the f l u v i a l and h i l l s l o p e systems in which the sediments of G a l l i e Pond responded p r i m a r i l y to the development of the l a k e , r a t h e r than the h i l l s l o p e p r o c e s s e s . 5.4.2 6600 ~ 6340 years B.P. The p e r i o d 6600 - 6340 years B.P. repr e s e n t s the end of the warm dry c o n d i t i o n s of the hypsithermal i n t e r v a l . The s t r a t i g r a p h i e s of the d e p o s i t s f o r t h i s p e r i o d are a d i s c o n t -inuous l a y e r of Mazama ash and f i b r o u s peat with woody f r a g -ments i n d i c a t i n g a t r e e l i n e above that of present. Consequent-l y the organic matter of the sediments i s high, and d e r i v e d from i n s i t u peat p r o d u c t i o n . The Mazama ash i n c o r p o r a t e d i n t h i s s e c t i o n of the sedimentary column i s a f i n e t e x t u r e d , w e l l s o r t e d d e p o s i t , a consequence of the d i s t a n c e from i t s source i n southern Oregon. The peat h o r i z o n i n which i t i s i n c o r p o r a t e d i s f i n e r ( i n terms of Mz) than those peaty h o r i z o n s below (Figure 5.7) although l e s s w e l l s o r t e d , a consequence of the i n t e r m i x i n g of ash and watershed sediments. The mineralogy of the sediments shows a strong imprint of t i l l , i n d i c a t i n g a s i m i l a r source area to that evident i n the 108 e a r l y p o s t g l a c i a l . A s l i g h t i n c r e a s e i n the e x t r a c t a b l e i r o n and aluminium content of the samples i n d i c a t e s that the h i l l s l o p e s were c o n t r i b u t i n g and i n c r e a s i n g l y weathered m a t e r i a l was accumulating. The element content of the stratum i s dominated by the enrichment of the Mazama ash h o r i z o n with Mg. The i n f l u x r a t e s f o r t h i s p e r i o d , i n terms of both volume and mass of c l a s t i c sediment, are the h i g h e s t recorded over the p o s t g l a c i a l time p e r i o d . However, at t h i s time the lake had d r i e d up and the Mosquito and Hummingbird streams were flowing i n f r e q u e n t l y , i f at a l l . P o s s i b l e e x p l a n a t i o n s f o r the i n f l u x r a t e s i n c l u d e : a l a r g e input of Mazama ash by d i r e c t a i r - f a l l ; , the exposure of the t i l l s h e l f by a f a l l i n water l e v e l and an i n c r e a s e i n a e o l i a n a c t i v i t y w i t h i n the catchment; a f i r e i n the catchment during t h i s i n t e r v a l , as evidenced by the char-c o a l i n c o r e s C1 and H1; or, the r e l a t i v e l y high t r a p e f f i c e n c y of the peat during i t s growth phase, f o r a l l s i z e f r a c t i o n s , a l s o e x p l a i n i n g the poor s o r t i n g of the d e p o s i t s . 5.4.3 6340 - 2400 years B.P. T h i s p e r i o d i s one c h a r a c t e r i s e d by g e n e r a l c o o l i n g and the onset of n e o g l a c i a l c o n d i t i o n s . T h i s i s evidenced i n the s t r a t i g r a p h y by the accumulation of i n o r g a n i c c l a s t i c sediments which rep r e s e n t a r i s e of the water t a b l e and the f l o o d i n g of the s i t e to form a shallow l a k e . The organic matter i n c o r -porated i n the sediments i s p r i m a r i l y a l l o c h t h o n o u s fragments of woody m a t e r i a l d e r i v e d from the i n f l u x of decomposing v e g e t a t i o n and dead t r e e s l e f t behind as the t r e e - l i n e 109 r e t r e a t e d . The d e p o s i t s are the f i n e s t that have accumulated in the lake r e c o r d (Mz 5.80). They are moderately s o r t e d (1.520) and n e g a t i v e l y skewed (-0.46). T h i s i n d i c a t e s the importance of the input of the f i n e s i l t s and coarse c l a y i n t o the l a k e . Pedogenic development d u r i n g the warm c o n d i t i o n s of the hypsithermal i n t e r v a l r e s u l t e d i n g r e a t e r weathering of the h i l l s l o p e d e p o s i t s . T h i s i s i n d i c a t e d by the f a c t that the element content of the sediments i n t h i s p e r i o d i s one of the highest recorded, most no t a b l y f o r A l , Ba, Ca, S i , and Sr. An increase i s a l s o evident i n the e x t r a c t a b l e i r o n and aluminium content, i n d i c a t i n g i n f l u x of sediment from the h i l l -s l o p e s . R e t r e a t of the t r e e l i n e and a decrease i n the v e g e t a t -ion cover exposed these d e p o s i t s d u r i n g t h i s p e r i o d r e s u l t i n g in g r e a t e r s u r f a c e e r o s i o n . The accumulation of sediment both in terms of volume and i n f l u x of c l a s t i c sediment i s the lowest recorded i n the p o s t g l a c i a l p e r i o d . Hence t h i s p e r i o d i s one of l i m i t e d a c t i v i t y i n terms of the volume of sediment moved, but marks the onset of the input of dominantly pedogenic weathered sediments. 5.4.4 2400 years B.P. to the present The sediments accumulating i n the p e r i o d 2400 - 0 years B.P. are the most i n o r g a n i c s i l t s , r e f l e c t i n g the onset of the c o o l e s t n e o g l a c i a l c o n d i t i o n s (Ryder et a l . , 1981). At the base 110 of the d e p o s i t s i s a s u b s t a n t i a l accumulation of Bridge R i v e r ash, c o n s i s t i n g of coarse shards of w e l l s o r t e d v o l c a n i c g l a s s r e f l e c t i n g the proximate source of the ash (Meager mountain ca. 45 km from the study a r e a ) . There i s an absence of m o n t m o r i l l o n i t e i n the lake sediments, one of the primary weathering products of Bridge River ash evident i n the s o i l s of the catchment, i n d i c a t i n g that the ash was d e p o s i t e d d i r e c t l y i n t o the lake with l i t t l e subsequent m o b i l i s a t i o n . The Bridge River ash p r o v i d e s an important input of p l a g i o c l a s e i n t o the system, and i s a l s o very high i n Na and P. The o v e r l y i n g l a c u s t r i n e s i l t s have the lowest organic matter content of the d e p o s i t s i n the l a k e . These s i l t s are f i n e t e x t u r e d , Mz 5.51c6, moderately s o r t e d , and s t r o n g l y n e g a t i v e l y skewed. T h e i r mineralogy, e x t r a c t a b l e i r o n and aluminium and element content a l l i n d i c a t e a pedogenic source fo r the sediment, probably the s u r f a c e of the h o r i z o n s of the b r u n i s o l s and r e g o s o l s . The p e r i o d i s c h a r a c t e r i s e d by an i n c r e a s e i n c l a s t i c sediment e r o s i o n from the catchment to 2.3 x 10-" + 6.7 x 10- 5 kg/m 2/yr. T h i s appears to be r e l a t e d to the wetter c o n d i t i o n s and the r e l a t i v e importance of f l u v i a l and the s u r f a c e wash pro c e s s e s . 5.5 Regional context I n t e r p r e t a t i o n of the c h a r a c t e r i s t i c s of the lake s e d i -ments of G a l l i e Pond i n d i c a t e s r e l a t i v e s t a b i l i t y and quiescence 111 in terms of geomorphic a c t i v i t y i n the Goat Meadows watershed throughout much of the Holocene Epoch. In gen e r a l the water-shed's response, as recorded i n the lake sediments, was r e l a t -i v e l y i n s e n s i t i v e to palaeoenvironmental change, however, a number of events with r e g i o n a l s i g n i f i c a n c e can be commented upon. The c o n d i t i o n s of flo w i n g water i n the p e r i o d immediately f o l l o w i n g d e g l a c i a t i o n at t h i s s i t e i n d i c a t e a p e r i o d of high energy e r o s i o n a l c o n d i t i o n s r e s p o n s i b l e f o r the removal of g l a c i a l ' s e d i m e n t s from the watershed. Such events are i n accordance with the suggestions of Church and Ryder (1972) of p a r a g l a c i a l sedimentation i n lowland s i t e s throughout southern B r i t i s h Columbia i n the e a r l y p o s t g l a c i a l p e r i o d . The i n d i c a t i o n from t h i s study i s that t h i s episode of inc r e a s e d geomorphic a c t i v i t y may have been completed, at l e a s t i n a l p i n e / s u b a l p i n e catchments, much e a r l i e r than the 6600 years B.P. which they suggest. I t i s probable that the hig h energy e r o s i o n a l c o n d i t i o n s at t h i s s i t e r e s u l t e d i n the removal of g l a c i a l sediment p r i o r to 10,000 years B.P. and a f t e r that c o n d i t i o n s of s t a b i l i t y and low e r o s i o n a l energy c h a r a c t e r i s e d the drainage b a s i n . The h y p s i t h e r m a l - n e o g l a c i a l boundary i s time t r a n s g r e s s i v e and at present there i s no consensus of o p i n i o n r e g a r d i n g the time of t h i s c l i m a t i c t r a n s i t i o n to southwestern B r i t i s h Columbia (Ryder et a l . , 1981). Some p a l y n o l o g i c a l s t u d i e s conducted near the coast suggest that the r e l a t i v e l y c o o l , wet 1 1 2 c o n d i t i o n s commenced about 3000 years B.P. (Heusser, 1973, 1981), w h i l s t s t u d i e s of the moraines of four Coast Mountains g l a c i e r s (Ryder et a l . , 1981) and of a l p i n e g l a c i e r s near G l a c i e r Peak in the northern Cascades (Beget, 1984) i n d i c a t e dates much e a r l i e r ca. 6000 and 5100 years B.P. r e s p e c t i v e l y . The r e s u l t s of t h i s study support the e a r l i e r date, as evidenced by the s t r a t i g r a p h i c change from peaty m a t e r i a l to more i n o r g a -n i c l a c u s t r i n e s i l t s ca. 6300 years B.P., i n d i c a t i n g the onset of wetter c o n d i t i o n s . The p r o g r e s s i v e decrease i n organic matter content i n the lake sediments r e p r e s e n t i n g the l a s t 6000 years, an index of net organic p r o d u c t i v i t y i n the catchment, lends support f o r the argument of p r o g r e s s i v e c o o l i n g of the three n e o g l a c i a l i n t e r v a l s . However, i t i s not p o s s i b l e to r e s o l v e each n e o g l a c i a l i n the lake sediment r e c o r d . T h i s study provides some i n d i c a t i o n that lake sediments p o t e n t i a l l y have much to o f f e r i n terms of i n s i g h t i n t o palaeo-geomorphic change, whether d e t e r m i n a t i o n s of sedimentation r a t e s , mechanisms of sediment t r a n s f e r or sediment sources. The h i g h l y c o n s e r v a t i v e nature of G a l l i e Pond's sedimentary response i n d i c a t e s that the Goat Meadows watershed has remained a r e l a t i v e l y low energy e r o s i o n a l system throughout the Holocene Epoch which has e x h i b i t e d l i t t l e s e n s i t i v i t y to palaeoenvironmental change, a r e s u l t probably r e p r e s e n t a t i v e of most b e d r o c k / t i l l veneer catchments at t h i s e l e v a t i o n . The g e o p h y s i c a l c h r a c t e r i s t i c s i n v e s t i g a t e d i n t h i s study provide i n s i g h t i n t o changes i n the water balance of the l a k e , gross changes in sediment sources, net o r g a n i c p r o d u c t i v i t y and s e d i -1 1 3 mentation r a t e s . I n s i g h t i n t o the more exact nature of palaeo-c l i m a t e i s dependent on p a l a e o b o t a n i c a l i n f o r m a t i o n . A more r i g o r o u s i n v e s t i g a t i o n of the methods and techniques employed i n t h i s study would be ob t a i n e d i n an a l p i n e / s u b a l p i n e water-shed which has experienced the e f f e c t s of Holocene a l p i n e g l a c i a t i o n or more e x t e n s i v e f l u v i a l a c t i v i t y . 1 1 4 CHAPTER 6 CONCLUDING COMMENTS The contemporary sediments of G a l l i e Pond are f i n e to medium s i l t s with r e l a t i v e l y low organic matter content of a l l o c h t h o n o u s o r i g i n . The temporal v a r i a b i l i t i e s of sedimentary c h a r a c t e r i s t i c s are v a r i e d : minerogenic bulk d e n s i t y and organic matter content e x h i b i t c o n s i d e r a b l e v a r i a b i l i t y c l o s e l y r e l a t e d to the l i t h o s t r a t i g r a p h y of the sediments; the t o t a l element content shows a marked i n c r e a s e with time; whereas, the mineralogy and t e x t u r a l p r o p e r t i e s have remained r e l a t i v e l y constant and i n s e n s i t i v e to palaeoenvironmental change. Sediment y i e l d as determined f o r four time p e r i o d s over the Holocene Epoch has v a r i e d by an order of magnitude. The g r e a t e s t v a l u e s were observed d u r i n g the hypsithermal i n t e r v a l (7.0 +2.7 x 10- 4) and over the l a s t 2400 years (3.17+0.97 x 10-"), with the lowest i n the p e r i o d 6300 to 2400 years B.P. (8.8 +1.6 x 1 0 - 5 ) . The mean r a t e of e r o s i o n (1.47_+0.42 x 10-") i s one order of magnitude lower than contemporary process measure-ments made at slope s i t e s i n the catchment. T h i s i l l u s t r a t e s one of the problems of p o i n t process measurements and s p a t i a l i n t e g r a i o n of r a t e s i n the d e t e r m i n a t i o n of sediment y i e l d , which i n t h i s case has undoubtedly r e s u l t e d i n an overestima-t i o n of the a e o l i a n and animal c o n t r i b u t i o n s . The r e s u l t s of the study i n d i c a t e that the Goat Meadows watershed has remained a r e l a t i v e l y low energy e r o s i o n a l system throughout the Holocene Epoch, which has e x h i b i t e d l i m i t e d s e n s i t i v i t y to palaeoenvironmental change. Those changes which have been recorded i n the lake sediments, through the l i t h o -1 15 s t r a t i g r a p h y of the d e p o s i t s , r e l a t e p r i m a r i l y to the water balance of the l a k e . In the immediate p o s t g l a c i a l i n t e r v a l c o n d i t i o n s of flowing water w i t h i n the lake p r e v a i l e d d u r i n g which coarse o x i d i z e d sediments accumulated. During t h i s i n t e r v a l g l a c i a l sediment was removed from the watershed as p a r t of the. r e g i o n a l p a r a g l a c i a l episode to be d e p o s i t e d i n lowland s i t e s . I t i s probable that t h i s episode of enhanced geomorphic a c t i v i t y was completed by 10,000 years B.P., much e a r l i e r than the 6600 years B.P. c i t e d f o r lowland a r e a s . The remainder of the Holocene Epoch can be s u b d i v i d e d i n t o two time p e r i o d s c h a r a c t e r i s e d by d i s t i n c t i v e s e d i m e n t o l o g i c a l regimes. The f i r s t p e r i o d encompasses the e a r l i e r p a r t of the Holocene Epoch, 10,000 to 6300 years B.P. During the e a r l y part of t h i s i n t e r v a l the lake developed from c o n d i t i o n s of fl o w i n g water to a shallow lake with c l a s t i c sediment d e p o s i t i o n . The onset of warm dry c o n d i t i o n s of the hypsithermal i n t e r v a l r e s u l t e d i n a f a l l i n water l e v e l and development of a peat bog. During t h i s warmer d r i e r p e r i o d the watershed was charac-t e r i s e d by a higher t r e e l i n e and the sediment accumulating i n the lake was r e l a t i v e l y coarse, p o o r l y s o r t e d and d e r i v e d from t i l l d e p o s i t s . A r a p i d r i s e of water l e v e l c a . 6300 years B.P. r e s u l t e d i n the f l o o d i n g of the s i t e and the onset of i n o r g a n i c c l a s t i c sediment d e p o s i t i o n . T h i s t r a n s i t i o n suggests an e a r l y date f o r the h y p s i t h e r m a l / n e o g l a c i a l boundary i n south western B r i t i s h Columbia, i n accordance with c h r o n o l o g i e s f o r a l p i n e g l a c i e r s in the southern Coast Mountains and northern Cascades. 1 16 Throughout the l a s t 6000 years the watershed has had a lower t r e e l i n e than d u r i n g the e a r l y p o s t g l a c i a l and the m a t e r i a l accumulating in G a l l i e Pond has been f i n e r and d e r i v e d from pedogenic sources. The p r o g r e s s i v e decrease i n the organic matter content of the sediments r e p r e s e n t i n g the l a s t 6000 years, an index of net organic p r o d u c t i v i t y w i t h i n the c a t -chment, lends support f o r the p r o g r e s s i v e c o o l i n g of the three n e o g l a c i a l i n t e r v a l s . In g e n e r a l the sedimentary c h a r a c t e r i s t i c s f o r the post h y p s i t h e r m a l i n t e r v a l can best be e x p l a i n e d i n terms of the g r e a t e r c o u p l i n g between the h i l l s l o p e and l a k e sedimentary systems r e l a t e d to c o o l e r / w e t t e r c l i m a t i c c o n d i t i o n s and an i n c r e a s e d i n c i d e n c e of s u r f a c e wash. In a d d i t i o n the s t r a t i g -raphy of the s o i l s w i t h i n the catchment i n d i c a t e s that most a e o l i a n d e p o s i t i o n and r e m o b i l i s a t i o n has o c c u r r e d throughout t h i s p e r i o d i n c o n t r a s t to i t s supposed predominance in the pre-6000 year B.P. i n t e r v a l documented i n other p a r t s of the p r o v i n c e . 1 17 REFERENCES CITED Ager, D.V., 1973: The nature of the s t r a t i g r a p h i c r e c o r d . Wiley, New York, I22p. A l l e y , N.F., 1976: The palynology and p a l a e o c l i m a t i c s i g n i f i c a n c e of a dated core of Holocene peat, Okanagan v a l l e y , southern B r i t i s h Columbia. Canadian J o u r n a l of  Earth S c i e n c e s , 13, 1131-1144. Anderson, R.Y., Nunfer, E.B. and Dean, W.E., 1984: S i n k i n g of v o l c a n i c ash i n uncompacted sediment i n W i l l i a m s Lake, Washington. Science, 225, 505-508. Andrews, J.T., C a r r a r a , P.E., King, F.B. and Stuckenrath, R., 1975: Holocene environmental change i n the a l p i n e zone, Northern San Juan Mts., Colorado: Evidence from bog s t r a t i g r a p h y and p a l y n o l o g y . Quaternary Research, 5, 173-197. Arduino, E., B o r b e r i s , E., C a r r a r o , F. and Forno, M.G., 1984: E s t i m a t i n g r e l a t i v e ages from i r o n o x i d e / t o t a l i r o n r a t i o s of s o i l s i n the western Po v a l l e y . Geoderma, 33, 39-52. Barnosky, C.W., 1981: Late Quaternary v e g e t a t i o n from Davis Lake, Southern Puget Lowland; Washington. Quaternary  Research, 16, 221-240. B a r r e t t , G.E., 1981: Streamflow gener a t i o n i n the Coast Mountains of B r i t i s h Columbia. Unpubl. M.Sc. T h e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 89p. Beget, J.E., 1984: Tephrochronology of l a t e Wisconsin d e g l a c i a t i o n and Holocene g l a c i e r f l u c t u a t i o n s near G l a c i e r Peak, N. Cascade Range, Washington. Quaternary  Research, 21, 304-317. Berglund, B.E., 1979: P a l a e o h y d r o l o g i c a l changes i n the temperate zone i n the l a s t 15000 years. Subproject B, Lake  and Mire environments. Dept. Quaternary Geology, Lund, 140p. B i n f o r d , M.W., 1983: Palaeolimnolgy of the Peten Lake d i s t r i c t , Guatemala 1. E r o s i o n and d e p o s i t i o n of o r g a n i c sediments as i n f e r r e d from granulometry. H y d r o b i o l o g i a , 103, 119-204. B i r g e , E.A. and Juday, C , 1934: P a r t i c u l a t e and organic matter i n i n l a n d l a k e s . E c o l o g i c a l Monograph, 4, 440-474. B i r k e l a n d , P.W. and Andrews, J.T., 1982: Lake sediment and s o i l c hemistry i n an a l p i n e area of the Colorado Front Range. F i n a l r e port to the Colorado commission on higher 1 18 education p r o j e c t . B i r k e l a n d , P.W., Burke, R.M. and Walker, A.L., 1979: V a r i a t i o n in chemical parameters of Quaternary s o i l s with time and a l t i t u d e , S i e r r a Nevada, C a l i f o r n i a . G e o l o g i c a l S o c i e t y  America A b s t r a c t s with Programs, 11, 388. Black, C.A., 1965: Methods of s o i l a n a l y s i s . American S o c i e t y of Agronomy, Monograph 9, v o l 1, 770p. Bloemandal, J . , O l d f i e l d , F. and Thompson, R., 1979: Magnetic measurements used to assess sediment i n f l u x at L l y n Goddiondun. Nature, 200, 50-53. B o r t l e s o n , G.C. and Lee, G.F., 1975: Recent sedimentary h i s t o r y of Lake Monona, Wisconsin. Water, A i r and S o i l P o l l u t i o n , 4, 89-98. Bovis, M.J., 1982: The s p a t i a l v a r i a t i o n of s o i l l o s s and s o i l l o s s c o n t r o l s . In Thorn, C.E., (ed.) Space and time i n  Geomorphology. A l l e n and Unwin, London, 1-25. Bray, D.I., 1972: G e n e r a l i s e d regime-type a n a l y s i s of A l b e r t a r i v e r s . Unpubl. Ph.D. T h e s i s , U n i v e r s i t y of A l b e r t a , Edmonton, 232p. B r i t i s h Columbia, M i n i s t r y of Environment, 1984: Snow survey  b u l l e t i n . Water management branch, May .1 , 1984. Bruland, K,W., Koide, M., Bowser, C , Maher, L . J . and Goldberg, E.D., 1975: Lead 210 and p o l l e n geochronologies of Lake S u p e r i o r . Quaternary Research, 5, 89-98. Caine, T.N., 1974: The geomorphic processes of the a l p i n e environment. In Ives, J.D. and Barry, R.G., (eds.), A r c t i c  and a l p i n e environments. Methuen, London, 721-748. Canadian S o i l Survey Committee, 1978: The system of s o i l c l a s s i f i c a t i o n f o r Canada. A g r i c u l t u r e Canada, Queens P r i n t e r , Ottawa, 164p. C a r r o l l , D., 1970: Clay m i n e r a l s : a guide to t h e i r X-ray i d e n t i f i c a t i o n . G e o l o g i c a l S o c i e t y America S p e c i a l Paper 126, 80p. Chorley, R.J. and Kennedy, B.A., 1971: P h y s i c a l geography: a  systems approach. P r e n t i c e - H a l l , London, 370p. Church, M., 1980: Records of recent geomorphological events. In C u l l i n g f o r d , R.A., Davidson, D.A., and Lewin, J . , (e d s . ) , Timescales in geomorphology. Wiley and Sons L t d . , C h i c h e s t e r , 13-29. 1 1 9 Church, M. and Ryder, J.M., 1972: P a r a g l a c i a l sedimentation: a c o n s i d e r a t i o n of f l u v i a l processes c o n d i t i o n e d by g l a c i a t i o n . G e o l o g i c a l S o c i e t y America B u l l e t i n , 83, 3059-3072. Clague, J . J . , 1981: Late Quaternary geology and geochronology of B r i t i s h Columbia. Part 2: summary and d i s c u s s i o n of radiocarbon dated Quaternary h i s t o r y . G e o l o g i c a l Survey  of Canada Paper, 80-35, 41p. Davis, M.B., 1976: E r o s i o n r a t e s and land.use h i s t o r y i n southern Michigan. Environmental Conservation, 3, 139-148. Davis, P.T., Upson, S. and Waterman, S.E., 1979: L a c u s t r i n e sediment v a r i a t i o n as an i n d i c a t o r of l a t e Holocene c l i m a t i c f l u c t u a t i o n . G e o l o g i c a l S o c i e t y America  A b s t r a c t s with Programs, 11, 410. Dearing, J.A., 1982: Core c o r r e l a t i o n and t o t a l sediment i n f l u x . In Berglund, B.E., (ed.), P a l a e o h y d r o l o g i c a l  changes i n the temperate zone i n the l a s t 15,000 years.  Sub-project B, Lake and Mire environments. IGCP 158, 1-21 . Dearing, J.A., 1983: Changing p a t t e r n s of sediment accumulation i n a small lake i n Scania, southern Sweden. H y d r o b i o l o g i a , 103, 59-65. Dearing, J.A. and Flower, R.J., 1982: The magnetic s u s c e p t i b i l i t y of sedimentary m a t e r i a l trapped i n Lough Neagh, Northern I r e l a n d , and i t s e r o s i o n a l s i g n i f i c a n c e . Limnology Oceanography, 27, 969-975. Dearing, J.A., E l n e r , J.K., and Happey-Wood, C.N., 1981: Recent sediment f l u x and e r o s i o n a l processes i n a Welsh upland lake-catchment based on magnetic s u s c e p t i b i l i t y measurements, Quaternary Research, 16, 356-372. Dearing, J.A.-, F o s t e r , I.D.L. and Simpson, A.D., 1982: Timescales of denudation: the lake drainage b a s i n approach. In Recent developments i n e x p l a n a t i o n and p r e d i c t i o n of e r o s i o n and sediment y i e l d . IAHS Publ., 137, 351-360. Dendy, F.E., Champion, W.A and Wilson, R.B.. 1973: R e s e r v o i r sedimentation surveys i n the United S t a t e s . In Ackerman, W.C., White, G.F. and Worthington, E.B., (e d s . ) , Man-made  l a k e s : t h e i r problems and environmental e f f e c t s , American G e o p h y s i c a l Union Monograph, 17, 349-359. D i g e r f e l d t , G., 1972: The p o s t g l a c i a l development of Lake Trummen. F o l i a L imnologica S c a n d i n a v i c a , 16. 1 20 D i g e r f e l d t , G., Battarbee, R.W. and Benglsson, L., 1975: Report of a n n u a l l y laminated sediments in lake J a r l a s j o n . G e o l ogiska Foreningens i Stockholm F o r h h a n l i n g e r , 97, 29-40. Duford, J.M. and Osborn, G.D., 1978: Holocene and l a t e s t P l e i s t o c e n e c i r q u e g l a c i a t i o n s i n the Shuswap Highland, B r i t i s h Columbia. Canadian J o u r n a l of E a r t h S c i e n c e s , 15, 865-873. D i s c u s s i o n by A l l e y , N.F. and r e p l y by Duford, J.M. and Osborn, G.D. (1980), Canadian J o u r n a l  of E a r t h S c i e n c e s , 17, 797-800. Edwards, K.J., and Rowntree, K.M., (1980) Radiocarbon and palaeoenvironmental evidence f o r changing r a t e s of e r o s i o n at a F l a n d r i a n s i t e i n S c o t l a n d . In C u l l i n g f o r d , R.A., Davidson, D.A., and Lewin, J . , (e d s . ) , Timescales in Geomorphology. John Wiley and Sons L t d . , 207-223. Fol k , R.L., 1964: A review of g r a i n - s i z e parameters. Sedimentology, 6, 73-93. F o l k , R.L. and Ward, W.L., 1957: Brazos r i v e r bar: a study on the s i g n i f i c a n c e of g r a i n s i z e parameters. J o u r n a l of  Sedimentary P e t r o l o g y , 27, 3-26. Frey, D.G., 1969: The r a t i o n a l e of palaeolimnology. M i t t e i l u n g e n I n t e r n a t i o n a l e r V e r e i n fur Limnologie, 17, 7-18. Friedman, G.M., 1962: On s o r t i n g , s o r t i n g c o e f f i c e n t s , and the l o g n o r m a l i t y of the g r a i n s i z e d i s t r i b u t i o n of sandstones. J o u r n a l Geology,.70, 737-756. F u l t o n , R., 1971: Radiocarbon geochronology of southern B r i t i s h Columbia. G e o l o g i c a l Survey of Canada Paper, 71-37. F u l t o n , R.J., 1975: Quaternary s t r a t i g r a p h y south c e n t r a l B r i t i s h Columbia. In The l a s t g l a c i a t i o n , IUGS-UNESCO I n t e r n a t i o n a l G e o l o g i c a l C o r r e l a t i o n Programme, P r o j e c t 73-1-24, Western Washington S t a t e C o l l e g e , Department of Geology, Bellingham, Washington, Guidebook f o r F i e l d conference, 98-124. G a l l i e , T.M., 1983: Chemical denudation and hydrology near t r e e l i m i t , Coast Mountains, B r i t i s h Columbia. Unpubl. Ph.D. T h e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 262 p. G a l l i e , T.M. and Slaymaker, H.O., 1983: V a r i a b l e s o l u t e sources and h y d r o l o g i c pathways i n a c o a s t a l s u balpine environment In W a l l i n g , D.E. and Burt, T.P., (e d s . ) , Watershed  experiments, Geo Books, Norwich, 347-359. 121 Gees, R.A. , 1964: Momement measures i n r e l a t i o n to the d e p o s t i o n a l environment of sands. E c l o g . g e o l . Helv., 58, 209-213. G i l b e r t , R., 1973: Observations of l a c u s t r i n e sedimentation at L i l l o o e t Lake, B r i t i s h Columbia. Unpubl. Ph.D. T h e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, I93p. G r i f f i t h s , J.C., 1967: S c i e n t i f i c method i n a n a l y s i s of  sediments. McGraw-Hill, New York, 508 p. Hart, J.S., 1979: C l a s t i c sediment sources and suspended sediment y i e l d i n a Coast Mountains watershed, B r i t i s h Columbia. Unpubl. M.Sc. T h e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 75p. Heusser, C.J., 1973: Environmental sequence f o l l o w i n g the Fr a s e r advance of the Juan de Fuca lobe, Washington. Quaternary Research, 3, 284-306. Heusser, C.J., 1977: Quaternary palynology of the P a c i f i c slope of Washington. Quaternary Research, 8, 282-306. Heusser, C.J., 1978: Palynology of Quaternary d e p o s i t s of the lower B o g a c c h i e l R i v e r area, Olympic P e n i n s u l a , Washington. Canadian J o u r n a l of E a r t h S c i e n c e s , 15, 1568-1578. Heusser, C.J., Heusser, L.E. and S t r e e t e r , S.S., 1980: Quaternary temperatures and p r e c i p i t a t i o n from North west coast of N. America. Nature, 286, 702-704. H i l l e l , D., 1971: S o i l and water: P h y s i c a l p r i n c i p l e s  and processes. Academic Press, New York, 288p. Hilton-Johnson, W., 1982: I n t e r r e l a t i o n s h i p s among geomorphic i n t e r p r e t a t i o n s of the s t r a t i g r a p h i c r e c o r d , process geomorphology and geomorphic models. In Thorn, C.E., (ed.), Space and Time i n Geomorphology. A l l e n and Unwin, London, 219-243. Hutchinson, G.E., 1957: A t r e a t i s e on limnology. Wiley, New York, V o l . 1. Jones, B.F. and Bowser, C.J., 1978: The mineralogy and r e l a t e d chemistry of lake sediments. In Lerman, A., (ed.), Lakes: Chemistry, Geology and P h y s i c s . S p r i n g e r -V e r l a g , New York, 179-236. Jones, P.S.A., 1982: Sediment movement i n a sub- a l p i n e b a s i n i n the Coast Mountains of B r i t i s h Columbia. Unpubl. M.Sc. T h e s i s , The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 1 7 1 p. 1 22 Karasek, F.W., 1970: M i c r o m e t r i c s . . . Research/Development, 21, 59-62. Keulder, C , 1982: P a r t i c l e s i z e d i s t r i b u t i o n and chemical parameters of the sediments of a shallow t u r b i d impoundment. H y d r o b i o l o g i a , 91, 341-353. Ki r k b y , M.J., 1971: H i l l s l o p e process-response models. I n s t i t u t e  of B r i t i s h Geographers S p e c i a l P u b l i c a t i o n , 3, 15-30. Ki r k b y , M.J., 1978: I m p l i c a t i o n s f o r sediment t r a n s p o r t . In Kirkby, M.J., (ed.) H i l l s l o p e hydrology, Wiley, 325-364. L a v k u l i c h , L.M., 1981: Methods manual, pedology l a b o r a t o r y . Department of S o i l Science, The U n i v e r s i t y of B r i t i s h Columbia, Vancouver, 121p. Lehman, J.T., 1975: R e c o n s t r u c t i n g the r a t e s of accumulation of lake sediments. E a r t h P l a n e t a r y Science L e t t e r s , 11, 407-414. Li k e n s , G.E. and Davis, M.B., 1975: Post g l a c i a l h i s t o r y of M i r r o r Lake and i t s watershed i n New Hampshire, U.S.A. I n t e r n a t i o n a l e V e r e i n Theor. Agnew. Limnologie Verh., 19, 982-993. Lowdon, J.A. and Blake, W., 1968: G e o l o g i c a l Survey of Canada radiocarbon dates V I I . Radiocarbon, 10, 207-245. Mackereth, F.J.H., 1965: Chemical i n v e s t i g a t i o n s of lake sediments and t h e i r i n t e r p r e t a t i o n . Proceedings Royal  S o c i e t y B, 161, 295-309. Mackereth, F.J.H., 1966: Some chemical o b s e r v a t i o n s on post-g l a c i a l sediments. P h i l o s o p h i c a l T r a n s a c t i o n s Royal  S o c i e t y B, 250, 165-213. Ma l a u r i e , J . , V a s a r i , V., Hyvarinen, H., D e l i b r i a s , G. and Labeyne, J . , 1972: P r e l i m i n a r y remarks on Holocene p a l a e o c l i m a t e i n the regions of Thule and I n g l e f i e l d l a n d . In V a s a r i , V., (ed.) C l i m a t i c changes i n a r c t i c areas  d u r i n g the l a s t 10,000 ye a r s . Acta U n i v e r s i t y , O u l u e n s i s , S e r i e s A, U n i v e r s i t y , Oulu, F i n l a n d , 105-133. Mason, C.C. and F o l k , R.L., 1958: D i f f e r e n t i a t i o n of beach, dune and a e o l i a n f l a t environments by s i z e a n a l y s i s , Mustang I s l a n d , Texas. J o u r n a l of Sedimentary  P e t r o l o g y , 28, 211-226. Mathewes, R.W., 1973: A p a l y n o l o g i c a l study of p o s t g l a c i a l v e g e t a t i o n changes i n the U n i v e r s i t y r e s e a r c h f o r e s t , south-western B r i t i s h Columbia. Canadian J o u r n a l of  Botany, 51, 11, 2085-2103. 1 23 Mathewes, R.W. and Heusser, L.E., 1981: A 12,000 year p a l y n o l -g i c a l r e c o r d of temperature and p r e c i p i t a t i o n trends i n south western B r i t i s h Columbia. Canadian J o u r n a l of  Botany, 59, 707-710. Mathewes, R.W. and Rouse, G.E., 1975: Palynology and palaeoecology of p o s t g l a c i a l sediments from the lower F r a s e r R i v e r canyon of B r i t i s h Columbia. Canadian  J o u r n a l of E a r t h S c i e n c e s , 12, 745-756. Mathewes, R.W. and Westgate, J.A., 1980: Bridge River t e p h r a : r e v i s e d d i s t r i b u t i o n and s i g n i f i c a n c e f o r d e t e c t i n g o l d carbon e r r o r s i n radiocarbon dates of l i m n i c sediments i n southern B r i t i s h Columbia. Canadian J o u r n a l of E a r t h  S c i e n c e s , 17, 1454-1461. Mathewes, R.W., Borden, C.E. and Rouse, G.E., 1972: New radiocarbon dates f o r the Yale area of the lower F r a s e r R i v e r canyon, B r i t i s h Columbia. Canadian J o u r n a l of E a r t h  S c i e n c e s , 9, 1055-1057. Mathews, W.H., 1951: H i s t o r i c and p r e h i s t o r i c f l u c t u a t i o n s of a l p i n e g l a c i e r s i n the Mount G a r i b a l d i map area, south western B r i t i s h Columbia. J o u r n a l of Geology, 59, 357-380. Matter, A. and Tucker, M.E., 1978: Modern and a n c i e n t lake sediments: an i n t r o d u c t i o n . S p e c i a l P u b l i c a t i o n of the  I n t e r n a t i o n a l A s s o c i a t i o n of S e d i m e n t o l o g i s t s , 2, 1-6. Meade, R.H., 1969: E r r o r s i n using modern stream load data to estimate n a t u r a l r a t e s of denudation. G e o l o g i c a l S o c i e t y  America B u l l e t i n , 80, 1265-1274. Mehra, O.P. and Jackson, M.L., 1960: Iron oxide removal from s o i l s and c l a y s by a d i t h i o h i t e - c i t r a t e system b u f f e r e d with sodium b i c a r b o n a t e . C l a y s and c l a y m i n e r a l s , 5, 317-327. M i c r o m e t r i c s , 1978: Sedigraph p a r t i c l e s i z e a n a l y s e r . M i c r o m e t r i c s . M o i o l a , R.J. and Weiser, D., 1968: T e x t u r a l parameters an e v a l u a t i o n . J o u r n a l of Sedimentary P e t r o l o g y , 38, 45-53. Nasmith, H., Mathews, W.H. and Rouse, G.E., 1967: Bridge River ash and some other recent ash beds i n B r i t i s h Columbia. Canadian J o u r n a l of E a r t h Science, 4, 163-170. O l d f i e l d , F., 1977: Lakes and t h e i r drainage basins as u n i t s of sediment based e c o l o g i c a l study. Progress i n P h y s i c a l  Geography, 1, 460-504. 124 O l d f i e l d , F., 1981: Peats and lake sediments: formation, s t r a t i g r a p h y d e s c r i p t i o n and nomenclature. In Goudie, A., (ed.), Geomorphological Techniques. A l l e n and Unwin, London, 306-326. O l d f i e l d , F., Appleby, P.G. and Thompson, R., 1980: P a l a e o e c o l o g i c a l s t u d i e s of three lakes i n the highlands of Papua New Guinea: Chronology and sedimentation. J o u r n a l  of Ecology, 68, 457-477. O l d f i e l d , F., Barnosky, C , Leopold, E.B. and Smith, J.P., 1983 a: M i n e r a l magnetic s t u d i e s of lake sediments. H y d r o b i o l o g i a , 103, 37-44. O l d f i e l d , F., Battarbee, R.W. and Dearing, J.A., 1983 b: New approaches to recent environmental change. Geo g r a p h i c a l  J o u r n a l , 149, 167-181. Ostrem, G., 1975: Sediment t r a n s p o r t i n g l a c i e r meltwater streams. In G l a c i o f l u v i a l and g l a c i o l a c u s t r i n e  s edimentation. S p e c i a l P u b l i c a t i o n S o c i e t y Econ. Palaeont. Miner., T u l s a , 23, 101-122. O ' S u l l i v a n , P.E., Coard, M.A. and P i c k e r i n g , D.A., 1982: The use of laminated lake sediments on the e s t i m a t i o n and c a l i b r a t i o n of e r o s i o n r a t e s . In Recent developments i n the e x p l a n a t i o n and p r e d i c t i o n of e r o s i o n and sediment y i e l d . IAHS Publ., 137, 385-396. O ' S u l l i v a n , P.E., O l d f i e l d , F. and Battarbee, R.W., 1973: P r e l i m i n a r y s t u d i e s of Lough Neagh sediments: S t r a t i g r a p h y chronolgy and p o l l e n a n a l y s i s . In B i r k s , H.J.B. and West, P.G., (eds . ) , Quaternary p l a n t ecology. B l a c k w e l l , Oxford. Pennington, W., Howarth, E.Y., Bonny, A.P. and Lishman, J.P., 1972: Lake sediments i n northern S c o t l a n d . P h i l o s o p h i c a l  T r a n s a c t i o n s Royal S o c i e t y , B, 264, 191-294. Powers, H.A. and Wilcox, R.E., 1964: V o l c a n i c ash from Mt. Mazama and from G l a c i e r Peak. Science, 144, 1334-1335. Rantala, R.T.T. and L o r i n g , D.H., 1973: New low c o s t t e f l o n decomposition v e s s e l . Atomic Ab s o r p t i o n Newsletter, 12, 97-99. Rapp, A., 1960: Recent development of mountain sl o p e s i n Karkevagge and surroundings, northern S c a n d i n a v i a . Geographiska Annaler A, 42, 65-200. Rapp, A., Murray-Rust, D.H., C h r i s t i a n s o n , C. and Berry, L., 1972: S o i l e r o s i o n and sedimentation i n four catchments near Dodoma, Tanzania. G e o g r a f i s k a Annaler A, 54, 255-318. 1 25 Read, P.B., 1977: Meager Creek v o l c a n i c complex, southwestern B r i t i s h Columbia. Report of a c t i v i t i e s , Part A. G e o l o g i c a l  Survey of Canada, Paper, 77-1A, 277-281. Renberg, I. and Segerstrom, U., 1981: A p p l i c a t i o n s of varved lake sediments i n palaeoenvironmental s t u d i e s . Wahlenbergia, 7, 125-129. Roddick, J.A., 1976: Summary of the coast p l u t o n i c complex of B r i t i s h Columbia. G e o l o g i c a l S o c i e t y America A b s t r a c t s  with Programs•, 8, 405. Rubin, M. and Alexander, C , 1960: American J o u r n a l Science  Radiocarbon Supplement, 2, 161. Ryder, J.M., 1971: The s t r a t i g r a p h y and morphology of para-g l a c i a l fans i n s o u t h - c e n t r a l B r i t i s h Columbia. Canadian  J o u r n a l of E a r t h S c i e n c e s , 8, 279-298. Ryder, J.M., 1978: Geomorphology and l a t e Quaternary h i s t o r y of the L i l l o o e t a r e a . In S t r y d , A.H. and Lawhead, S., (eds.), Report of the L i l l o o e t a r c h a e o l o g i c a l p r o j e c t , 1 . A r c h a e o l o g i c a l Survey of Canada, Paper 73, 56-67. Ryder, J.M., 1981: Geomorphology of the southern part of the C o a s t a l Mountains of B r i t i s h Columbia. Z e i t s c h r i f t fur  Geomorpholgie Supplementband, 37, 120-147. Ryder, J.M., Thomson, B. and A l l e y , N.F., 1981: N e o g l a c i a l chronology f o r the southern Coast Mountains of B r i t i s h Columbia. Unpublished manuscript. . Schlee, J . , Uchupi, E. and Trumbell, J.V.A., 1964: S t a t i s t i c a l parameters of Cape Cod beach and a e o l i a n sands. G e o l o g i c a l  Survey of America P r o f e s s i o n a l Paper, 501-D, 118-122. S c h o f i e l d , R.K. and T a y l o r , A.W., 1955: The measurement of s o i l pH. S o i l Survey S o c i e t y America Proceedings, 23, 152-156. Shepherd, F.P. and Young, R., 1961: D i s t i n g u i s h i n g between beach and dune sands. J o u r n a l of Sedimentary P e t r o l o g y , 31, 196-214. Simola, H.L.K., Coard, M.A. and O ' S u l l i v a n , P.E., 1981: Annual l a m i n a t i o n s i n the sediments of Loe Pool, C o r n w a l l . Nature, 290, 238-241. Slaymaker, H.O., 1977: E s t i m a t i o n of sediment y i e l d s i n temperate a l p i n e environments. In E r o s i o n and s o l i d matter t r a n s p o r t i n i n l a n d waters. IAHS, Publ. 122, 109-117. Slaymaker, H.O. and G i l b e r t , R.E., 1972: Geomorphic process and lan d use changes i n the Coast Mountains of B r i t i s h 1 26 Columbia: a case study. In Macar, P. and P i s s a r t , A., (eds.) Processus p e r i g l a c i a i r e s e s t u d i e s sur l e t e r r a i n . U n i v e r s i t e de Lie g e , 269-279. Slaymaker, H.O. and McPherson, H.J., 1977: An overview of geomorphic process i n the Canadian C o r d i l l e r a . Z e i t s c h r i f t  f ur Geomorphologie, 21, 169-186. S l y , P.G., Thomas, R.L. and P e l l e t i e r , B.R., 1982: Comparison of sediment energy-texture r e l a t i o n s h i p s i n marine and l a c u s t r i n e environments. H y d r o b i o l o g i a , 91, 71-84. Snedecor, G.W. and Cochran, W.G., 1980: S t a t i s t i c a l Methods. (7th ed.), Iowa State Press, Ames, Iowa, 507p. Sohl, H., 1983: A p a l a e o e c o l o g i c a l i n v e s t i g a t i o n of the l a t e g l a c i a l and Holocene lake sediments of the Uddelelrmeer; methods and some p r o v i s i o n a l r e s u l t s . Quaternary Stud i e s  in Poland, 4, 237-247. Stephenson, R.A., 1970: On the use of g r a i n s i z e a n a l y s i s i n geomorphic s t u d i e s . P r o f e s s i o n a l Geographer, 22, 200-203. Swanson, F . J . , Janda, R.J., Dunne, R. and Swanston, D.N., 1982: Sediment budgets and r o u t i n g i n f o r e s t drainage b a s i n s . USDA F o r e s t S e r v i c e , PNW-141. Ti p p e r , J.C., 1983: Rates of sedimentation and s t r a t i g r a p h i c a l completeness. Nature, 302, 696-698. Thomas, R.L. , Kemp, A.I.W. and Lewis, C.F.M., 1973: The s u r f i c i a l sediments of Lake Huron. Canadian J o u r n a l E a r t h  S c i e n c e s , 10, 226-271. V i s h e r , G.S., 1969: Grain s i z e d i s t r i b u t i o n s and d e p o s i t i o n a l p r o c e s s e s . J o u r n a l of Sedimentary P e t r o l o g y , 39, 1074-1106. Warwick, W.F., 1980: Palaeolimnology of the Bay of Quinte, Lake O n t a r i o : 2800 years of c u l t u r a l i n f l u e n c e . Canadian  B u l l e t i n of F i s h e r i e s and Aquatic Scie n c e s , 206, 1-117. Westgate, J.A., 1977: I d e n t i f i c a t i o n and s i g n i f i c a n c e of l a t e Holocene tephra from O t t e r Creek, southern B r i t i s h Columbia, and l o c a l i t i e s i n w e s t - c e n t r a l A l b e r t a . Canadian  J o u r n a l of E a r t h S c i e n c e s , 14, 2593-2600. Wetzel, R.G., 1983: Limnology. Saunders C o l l e g e P u b l i s h i n g , P h i l a d e l p h i a , 767p. Woodsworth, J . , 1977: Geology Pemberton (92 J) map area. G e o l o g i c a l Survey of Canada, Ottawa. 1 27 APPENDIX I REPRESENTATIVE SOIL PROFILE DESCRIPTIONS OF THE GOAT MEADOWS WATERSHED For exact sampling l o c a t i o n s see F i g u r e 4.2. PEDON: ORTHIC HUMO FERRIC PODSOL (83-6-1) Topography: C r e s t of a small h i l l 5 m above G a l l i e Pond. Surface i s g e n t l y s l o p i n g at 5° to the southwest Hydrology: Well d r a i n e d , snow melts e a r l y i n the season Parent m a t e r i a l : Boulders and stones from t i l l c o n s t i t u t e at l e a s t 30% of p r o f i l e . Compacted t i l l o v e r l i e s bedrock q u a t r z d i o r i t e . Capped by l o e s s , organic h o r i z o n s and at l e a s t one v o l c a n i c ash V e g e t a t i o n : Tree i s l a n d c a . 50 m2 surrounded by heath and dwarf t r e e a s s o c i a t i o n Horizon Depth(cm) D e s c r i p t i o n LFH 3.0-0.0 Dark r e d d i s h brown (5YR 2.5/2); compressed org a n i c mat composed of f i r needles i n a matrix of organic matter; abrupt wavy boundary; 1 to 5 cm t h i c k . Ae 0.0-0.5 Brown (7.5YR 5/2) loam; loose f r i a b l e , s l i g h t l y s t i c k y , not p l a s i c ; s t r u c t u r e l e s s abrupt, i r r e g u l a r boundary; 1 to 6 cm t h i c k . V o l c a n i c g l a s s ca. 10% i n very f i n e and coarse s i l t f r a c t i o n . II Bhf 5.0-11.0 Dark r e d d i s h brown (5YR 3/2) loam; s o f t f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; s t r u c t u r e l e s s ; abrupt i r r e g u l a r boundary; 3 to 7 cm t h i c k . III B f j 11.0-27.0 Y e l l o w i s h yellow (5YR 5/6) g r a v e l l y , sandy loam with many coarse d i s t i n c t dark r e d d i s h brown (5YR 3/2) mottles o c c u r i n g mostly along t r e e r o o t s and cobbles i n the matrix; s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c , very weak subangular coarse blocky s t r u c t u r e ; smooth c l e a r boundary; 14-17 cm t h i c k . I l l BC 27.0-38.0 L i g h t o l i v e gray (5Y 6/2) g r a v e l y loam sand with medium, d i s t i n c t dark r e d d i s h brown (2.5YR 3/4) mo t t l e s ; stones > 30% of h o r i z o n ; s l i g h t l y hard; compacted, 128 f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; few coarse r o o t s ; s t r u c t u r e l e s s ; i r r e g u l a r , abrupt boundary; 10-20 cm t h i c k . IV R 38.0 + Quartz d i o r i t e PEDON: ORTHIC DYSTRIC BRUNISOL(83-6-2) Topography: Quite steep s l o p i n g h i l l s l o p e to NW of pond ca. 20 m i n l e n g t h , SW f a c i n g . Hydroloogy: Well d r a i n e d , snow f r e e e a r l y i n the season Parent m a t e r i a l : C o n s o l i d a t e d t i l l o v e r l a i n by t h i n veneer of a e o l i a n l o e s s . P r i m a r i l y c o l l u v i u m . V e g e t a t i o n : Heather-Sedge a s s o c i a t i o n c a . 80% cover. Horizon Depth(cm) D e s c r i p t i o n LFH 1.0-0.0 Moss and l i c h e n mat o v e r l i e decomposing heath needles; t h i c k ; abrupt, smooth boundary; 0.5-1.5 cm t h i c k . Ah 0.0-6.0 Gray (10YR 5/1) f i n e sandy loam; s o f t f r i a b l e ; non s t i c k y , s l i g h t l y p l a s t i c ; weak p l a t y to s t r u c t u r e l e s s ; abundant very f i n e and f i n e v e r t i c a l r o o t s ; few medium r o o t s ; c l e a r wavy boundary; 5 to 9 cm t h i c k . Bm 6.0-18.0 Brown (10 YR 4/3) f i n e sandy loam; s o f t , very f r i a b l e ; non s t i c k y , s l i g h t l y p l a s t i c ; s t r u c t u r e l e s s ; p l e n t i f u l very f i n e and f i n e v e r t i c a l r o o t s ; gradual i r r e g u l a r boundary; 5 to 20 cm t h i c k . II Bmb 18.0-30.0 Brown (7.5 YR 4/4) g r a v e l l y loam; s o f t f r i a b l e ; non s t i c k y , non p l a s t i c , s t r u c t u r e l e s s p l e n t i f u l very f i n e , f i n e and coarse r o o t s ; gradual i r r e g u l a r boundary; 10 to 14 cm t h i c k . II BC 30.0-48.0 Y e l l o w i s h red (5YR 4/6) g r a v e l l y sandy loam; s o f t , very f r i a b l e ; non s t i c k y , non p l a s t i c ; s t r u c t u r e l e s s ; p l e n t i f u l very f i n e and coarse h o r i z o n t a l r o o t s ; gradual i r r e g u l a r boundary; 10 to 25 cm t h i c k . II C 48.0 + Y e l l o w i s h red (5YR 4/6) very g r a v e l l y 1 29 c o n s o l i d a t e d t i l l . PEDON: ORTHIC REGOSOL (Reg) Topography: C o l l u v i a l l y mantled a c t i v e slope i n excess of 60°. Subject to slumping and e r o s i o n . Hydrology: Well d r a i n e d l a t e snowpack. Parent m a t e r i a l : Colluvium from bedrock o v e r l y i n g Quartz d i o r i t e . V e g e t a t i o n : Unvegetated. Horizon Depth(cm) D e s c r i p t i o n C 0-15.0 O l i v e (5Y 5/3) g r a v e l l y coarse sand. Coarse fragments exceed 60% of h o r i z o n ; very f r i a b l e ; s t r u c t u r e l e s s ; 10 to 30 cm. t h i c k . II R 15 + Quartz d i o r i t e . PEDON: ORTHIC SOMBRIC BRUNISOL (83-2) Topography: WNW f a c i n g slope c a . 15-20°. A c t i v e with o c c a s i o n a l outcrops of quartz d i o r i t e . Hydrology: Well d r a i n e d , snow f r e e r e l a t i v e l y e a r l y i n the season. Parent m a t e r i a l : Compacted t i l l o v e r l a i n by c o l l u v i u m and f i n e r a e o l i a n m a t e r i a l . Near many exposed Marmot burrows. Gr a v e l at l e a s t 30% of a l l h o r i z o n s . V e g e t a t i o n : Sedge, Luetkea-Moss-Lichen a s s o c i a t i o n . Horizon Depth(cm) D e s c r i p t i o n Ah 0-4.0 Gray (10YR 5/1), g r a v e l l y sandy loam; f r i a b l e , s l i g h t l y s t i c k y , non p l a s t i c , s t r u c t u r e l e s s to f i n e g r a n u l a r ; t u r f y with abundant very f i n e , f i n e and medium v e r t i c a l r o o t s ; continuous smooth boundary; 3 to 6 cm t h i c k . Bm 4.0-15.0 Brown (10YR 5/3), g r a v e l l y sandy loam; s o f t , very f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; s t r u c t u r e l e s s to f i n e 1 30 g r a n u l a r ; abundant f i n e and medium v e r t i c a l r o o t s ; abrupt wavy boundary; 6 to 12 cm t h i c k . II Bmb 15.0-30.0. Strong brown (7.5 YR 5/6) g r a v e l l y sandy loam; s o f t , very f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; s t r u c t u r e l e s s ; abundant f i n e and medium v e r t i c a l r o o t s ; abrupt smooth boundary; 8 to 20 cm t h i c k . I I I C 30.0 + Compacted lodgement t i l l . PEDON: ORTHIC GLEYSOL (Gley) Topography: F l a t hollow, s i t e of incoming stream. Hydrology: Late l y i n g snow. Saturated at a l l times. P i t f i l l e d with water w i t h i n hours. Parent m a t e r i a l : Organic m a t e r i a l and f l u v i a l l y d e r i v e d e l a s t i c s o v e r l y i n g t i l l . V e g e t a t i o n : Sedge a s s o c i a t i o n . Horizon Depth(cm) D e s c r i p t i o n LFH 1.5-0.0 Sedge mat. Bmg 0.0-42.0 L i g h t brownish gray (10YR 6/2) with many f i n e y e l l o w i s h brown (10YR 5/8) mo t t l e s ; very f r i a b l e , s l i g h t l y s t i c k y , s l i g h t l y p l a s t i c ; s t r u c t u r e l e s s ; abundant f i n e medium r o o t s ; abrupt smooth boundary; 35 to 40 cm t h i c k . II C 42.0 + G r a v e l l y c o n s o l i d a t e d lodgement t i l l . 131 APPENDIX II MAJOR VEGETATION ASSOCIATIONS OF THE GOAT MEADOWS WATERSHED The taxonomic i d e n t i f i c a t i o n s i n t h i s Appendix are taken from G a l l i e (1983). The r e l a t i o n s h i p of these v e g e t a t i o n a s s o c i a t i o n s to the s o i l groups are repor t e d i n Table 3.2. TOLMIE SAXIFRAGA: C h a r a c t e r i s t i c : S a x i f r a g a t o l m i e i M a r s u p e l l a b r e v i s s i m a Luzula p i p e r i Juncus drummondi i I n c i d e n t a l : Carex p y r e n a i c a P o l y t r i t i c h u m sexangulare T h i s a s s o c i a t i o n i s found on a c t i v e d e b r i s lobes and t a l u s , cover approximately 5%. CASSIOPE, MOSS: C h a r a c t e r i s t i c : Cassiope mertensiana P o l y t r i c h u m sexangulaie I n c i d e n t a l : Juncus drummondi Luzula p i p e r i Carex n i g r i c a n s Rhancomitrium sudeticum Stereocaulon sp. Phyllodoce sp. Cassiope and Pol y t r i c h u m form moss and cobble meadows on pre-hypsithermal d e b r i s l o b e s . HEATH WITH DWARF TREES: C h a r a c t e r i s t i c : Cassiope mertensiana Phyllodoce empetriformis, intermedia, g l a n u f l o r i a  Abies l a s i o c a r p a  Luetka p e c t i n a t a  Lycopodium s i t c h e n s e  G a u l t h e r i a humifusa  Clado n i a sp. 1 32 I n c i d e n t a l : A r n i c a r y d b e r q i i E r i g e r o n p e r egrinus  Hieracium q r a c i l e  Deschampsia atropurpurea  P e d i c u l a r i s a r nithorhyncha T h i s a s s o c i a t i o n i n t e r g r a d e s with Lutkea, Moss, Lichens i n topographic d e p r e s s i o n s . LUTKEA, MOSS, LICHEN: C h a r a c t e r i s t i c : Lutkea p e c t i n a t a Rhasomitrium sudeticum S t e r o c a u l a n sp. S o l o r i n a crocea I n c i d e n t a l : Juncus p a r r y i , drummondii Carex s p e c t a b i l i s , n i g r i c a n s Lycopodium s i t c h e n s e H i e i a c i u m g r a c i l e Cassiope mertensiana C l a d o n i a sp. Luzula p i p e r i T h i s a s s o c i a t i o n i s commonly i n areas of s u r f a c e d e t e n t i o n storage adjacent to Heath and Heath-Sedge-Forb a s s o c i a t i o n s , DWARF SEDGE: C h a r a c t e r i s t i c : Carex n i g r i c a n s Juncus drummondi i  Deschampsia atropurpurea  Carex s p e c t a b i l i s  P o l t r i c h u m sexangulaie T h i s i s an a s s o c i a t i o n i n d i c a t i v e of s u r f a c e d e t e n t i o n storage and the most a c t i v e areas of ove r l a n d flow g e n e r a t i o n . HEATH, SEDGE, FORB: C h a r a c t e r i s t i c : Phyllodoce empetriformis Cassiope mertensiana  Leutkea p e c t i n a t a  Juncus p a r r y i  Pinus a l b i c a u l i s  Abies l a s i o c a r p a  Lupinus l a t i f o l i u s  Anemone o c c i d e n t a l i s  Deschampsia atropurpurea  Carex s p e c t a b i l i s 1 33 I n c i d e n t a l : Carex p y r e n a i c a S a x i f r a q a f e r r u q i n e a  E r i g e r o n p e r e i g i n u s  A r n i c a r y d b e r g i i  P e d i c u l a r i s racemosa  C l a d o n i a s p . H i e i a c i u m g r a c i l e  R h i z o c a r p o n g e o g r a p h i c a  A n t e n n a r i a a l p i n a P o t e n t i l l a f l a b e l l i f o l i a TREE ISLANDS: C h a r a c t e r i s t i c Inc i d e n t a l : A b i e s l a s i c a r p a  Tsuga m e r t e n s i a n a  P inus a l b i c a u l i s  V a c c i n i u m membranaccum  Rhododendron a l b i f o r u m  P h y l l o d o c e s p . Cass iope m e r t e n s i a n a  L u t k e a p e c t i n a t a  R i b i e s l a z i f o l i u m  L e t h a r i a c o l u m b i a n a  C l a d o n i a s p . T h i s a s s o c i a t i o n i s f ound o n l y on t h e h i g h e s t w e l l d r a i n e d s i t e s , w i t h l i g h t w i n t e r snowpacks. SEDGE, FORB, MOSS: C h a r a c t e r i s t i c : Carex n i g r i c a n s , s p e c t a b i1 i s Juncus d r u m m o n d i i , m e r t e n s i a n u s  E p i l o b i u m a l p i n u m , l a t i f o l i u m P h i l o n t i s f o n t a n a Inc i d e n t a l : Deschampsia a t r o p u r p u r e a  L e p t a r r h e n a p y r o l i f o l i a  S a x i f r a g a f e r r u g i n e a  V a l e r i a n a s i t c h e n s i s V e r a t r u m v i r i d e These s i t e s a r e c r y o t u r b a t e d and u n d e r l a i n by G l e y s o l s , SEDGE, SPHAGNUM: C h a r a c t e r i s t i c : Carex n i g r i c a n s , s p e c t a b i l i s Sphagnum o t h e r mosses T h i s a s s o c i a t i o n i s l i m i t e d t o t h e banks o v e r h a n g i n g t h e pond and seeps where wa te r i s a lways a b u n d a n t . 1 34 APPENDIX I I I CHRONOLOGICAL CONTROL C h r o n o l o g i c a l c o n t r o l f o r t h i s study i s p r o v i d e d through two r a d i o c a r b o n dates ( G a l l i e p e r s . comm.) and the p o s i t v e i d e n t i f i c a t i o n of Mazama and Bridge River ash i n the sediments of G a l l i e Pond (Rouse p e r s . comm.). The radiocarbon dates used are one of 10,510 +500 years B.P. on m a t e r i a l o v e r l y i n g the t i l l , and a date of 6340 +150 years B.P. on m a t e r i a l at the top of the peaty d e p o s i t s . The dates f o r the d e p o s i t i o n of the two ash l a y e r s , obtained from a review of p r e v i o u s s t u d i e s conducted i n southern B r i t i s h Columbia, are r e p o r t e d i n Table A I I I . 1 . For the purposes of t h i s study i t i s assumed that Mazama d e p o s i t i o n o c c u r r e d 6600 years B.P., and Bridge River ash 2400 years B.P. Table III.1 i n d i c a t e s the p o t e n t i a l e r r o r s a s s o c i a t e d with t h i s assumption. 135 Table III.1 Radiocarbon dates of Mazama and Bridge River ash d e p o s i t i o n Ash I n v e s t i g a t o r Study s i t e Lab. no, Date Mazama:Powers & Arrow lak e , Wash. W-776 Wilcox (1964) Rubin & Toketee F a l l s , Oregon W-888 Alexander (1960) 6600 + 400 6640 + 250 Bridge R i v e r : F u l t o n (1971) Mica Creek, B.C. Nasmith et a l . , Jesmond, B.C. (1967) Read (1978) Meager Mt.,B.C, Westgate (1977) P l i n t h Mt., B.C. GSC-1532 GSC-539 GSC-2587 S-581 2450 + 1 30 2440 + 1 40 2350 + 50 2550 + 80 1 3 6 A P P E N D I X I V L I T H O S T R A T I G R A P H Y O F T H E L A K E S E D I M E N T C O R E S T h i s a p p e n d i x p r e s e n t d i a g r a m s o f t h e s t r a t i g r a p h y o f e a c h o f 2 6 c o r e s c o l l e c t e d f r o m G a l l i e P o n d . E a c h s t r a t i g r a p h i c u n i t i s i d e n t i f i e d b y a s p e c i f i c s h a d i n g , t h e k e y t o w h i c h i s g i v e n b e l o w . T h e n u m b e r s t o t h e r i g h t o f e a c h o f t h e c o r e s r e p r e s e n t t h e M u n s e l l c o l o u r c o d e s t o b e s t d e s c r i b e t h e u n i t , a n d t h o s e t o t h e l e f t t h e d e p t h i n c m d o w n t h e c o r e . L a c u s t r i n e s i l t s L a c u s t r i n e s i l t s ft- + + • +• + & O r g a n i c m a t t e r B r i d g e R i v e r ash Mazama ash Peat O x i d i z e d sands Coarse sands T i l l B l B2 (10 YR 6 / 2 ) (10 YR 4 / 2 ) (10 YR 6 /2 ) 10 20 (10 YR 6 / 2 ) (10 YR 4 / 1 ) (10 YR 2 / 2 ) "-J«apDi (10 YR 7 / 4 ) (10 YR 6 / 2 ) C I C2 C3 + + + h + + + + + + + + h + + - 1 L + + + 4 (10 YR 6 / 1 ) (10 YR 7 / 2 ) (10 YR 3 / 2 ) (10 YR 4 / 2 ) (10 YR 5 / 2 ) C h a r c o a l ( 7 . 5 YR 5 / 8 ) (10 YR 6 / 2 ) 10 20. 30 J-40 + + t ,t t. J + + + + + + + + + + + + + + + + + + + + + + + (10 YR 6 / 2 ) 10 ( 7 . 5 YR 5 / 0 ) (10 YR 4 / 2 ) (10 YR 6 / 3 ) (10 YR 4 / 2 ) 20 (10 YR 6 / 1 ) ( 7 . 5 YR 5 / 0 ) (10 YR 6 / 3 ) (10 YR 3 / 2 K (10 YR 3 / 2 ) (10 YR 4 / 2 ) ( 2 . 5 Y 7 / 2 ) 138 D2 + + + h + + + + + v + + + + +, | + + + + + L* + - i . . - i (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 6 / 1 ) (10 YR 4 / 3 ) (10 YR 7 / 4 ) (10 YR 3 / 2 ) (10 YR 4 / 3 ) (10 YR 6 / 2 ) D3 10 20 30 40 50 + + + + + + + + + + + + + + + + + + + + (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 6 / 1 ) (10 YR 4 / 3 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) + + + ^  + + + (10 YR 4 / 2 ) (10 YR 4 / 3 ) (10 YR 6 / 1 ) E l 10 .20 30 40 + + + + + 10 YR 6 / 2 ) (10 YR 5 / 1 ) (10 YR 7 / 1 ) (10 YR 5 / 1 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 3 / 2 ) (10 YR 4 / 3 ) (10 YR 6 / 2 ) 139 E2 F l F2 h + + + + h + + + + + I- + + + + + I- + + + + + + + + + + K + + + + h + + + + + I + + + + + ^ + + + + + 1 + + + (10 YR 5 / 2 ) (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 4 / 1 ) (10 YR 4 / 2 ) (10 YR 3 / 2 ) (10 YR 7 / 4 ) (10 YR 3 / 2 ) (10 YR 4 / 2 ) (10 YR 6 / 2 ) 10\ 2W 30 + + -H + + + + + 4| - J L . _ 1 —I— ' — L | 40 50 J + + ^  + + + + + 4 + + (10 YR 6 / 3 ) (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 6 / 1 ) (10 YR 5 / 1 ) (10 YR 3 / 2 ) (10 YR 7 / 4 ) (10 YR 3 / 2 ) (10 YR 4 / 2 ) (10 YR 6 / 2 ) 10 204 30 40. 50 + + + •v. M + + -I + + + + + • + + + (10 YR 6 / 1 ) ( 7 . 5 YR 6 / 0 ) ( 7 . 5 YR 5 / 2 ) (10 YR 4 / 2 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 4 / 3 ) (10 YR 6 / 2 ) G l 10-+ + + + + + + + 20h 30 " J -4 0-+ + + + + H + + + + (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 4 / 3 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 4 / 3 ) (10 YR 6 / 2 ) ' H I I I 10 20 30 40 + + + + + +1 + + INIIIIIII —n + + + + (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 4 / 2 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 3 / 2 ) C h a r c o a l C h a r c o a l (10 YR 4 / 2 ) (10 YR 4 /3 ) ) (10 YR 6 / 2 ) 10 20 30 + + +1 + + + + +1 + + + + + +! 40-" J - " - A "a- -A 10 YR 6 / 2 ) (10 YR 7 / 1 ) (10 YR 6 / 2 ) (10 YR 5 / 1 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 Y r 4 / 2 ) + + i- + +1 + + t...t., (10 YR 4 / 3 ) (10 YR 5 / 8 ) (10 YR 6 / 2 ) J l O r ^ r - r r -2d TTTt 11 unrr + + + + + + + + + + + + + + + + (10 YR 6 / 2 ) (10 Y r 7 / 1 ) (10 YR 6 / 3 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 4 / 3 ) o Kl LI 10 j i 20'. 3 0 ' (10 YR 6 / 2 ) (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 5 / 1 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 4 / 3 ) ( 2 . 5 Y 7 / 2 ) 10 + + +, + + + + + + + + • + + + + + + + + + + + + + + + + + + 20-3a (10 YR 6 / 2 ) (10 YR 7 / 2 ) (10 YR 4 / 2 ) (10 YR 3 / 2 ) (10 YR 4 / 2 ) (10 YR 5 / 3 ) (10 YR 4 / 3 ) (10 YR 6 / 2 ) M l PI 10 20 -30 T + + + + + + + + + + + + + + + + + + + + + + + + + + + -JL-Ka IILII'.llll . _i_ _i y + + + + y + + +_ + (10 YR 6 / 1 ) (10 YR 7 / 1 ) (10 YR 4 / 1 ) (10 YR 5 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 4 / 1 ) (10 YR 6 / 1 ) 10 20 . + + + + • + + ^ (10 YR 6 / 2 ) (10 YR 7 / 3 ) (10 YR 6 / 1 ) (10 (10 YR YR 4 / 2 ) 7 / 4 ) (10 YR 4/2)1 (10 YR 4 / 3 ) . (10 YR 5 / 8 ) (10 YR 6 / 1 ) R l SI + •+ + f + + 4- * + 10 l l l l l l l l l l l l mmm. S2 (10 YR 6 / 1 ) (10 YR 5 / 2 ) (10 YR 4 / 2 ) 1 0 (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 5 / 2 ) (10 YR 6 / 1 ) 20 + + T + + + + + + + + + + + + + + ' + + +' k + + + + + (10 YR 6 / 1 ) • + + + + -t y + + + + H :uo (10 10 .(io (10 YR 5 / 2 ) (10 YR 4 / 2 ) (10 YR 4 / 1 ) (10 Y r 6 / 1 ) VI V2 (10 YR 6 / 1 ) (10 YR 4 / 2 ) (10 YR 7 / 4 ) (10 YR 4 / 2 ) (10 YR 6 / 1 ) (10 YR 5 / 8 ) (10 YR 6 / 1 ) (10 YR 6 / 1 ) (10 YR 4 / 2 ) (10 YR 6 / 2 ) 10 YR 6 / 1 ) 143 APPENDIX V LAKE SEDIMENT CHARACTERISTICS: PARTICLE SIZE AND TOTAL ELEMENT CONTENT Table V.1 P a r t i c l e s i z e c h a r a c t e r i s t i c s f o r s e l e c t e d lake sediment samples Core S t r a t i g r a p h i c Sand S i l t Clay Mz ai Ski KG' u n i t (%) (</>) (0) B2 CI C2 D3 F1 F2 I 1 L.S. L.S. L.S. L.S. L.S./B.R. L.S./O.M. P L . S . /O . M. O.S. L.S. L.S. L.S. L.S. L.S. L.S./B.R. L.S./O.M. L.S./O.M. P P/M P P L.S./O.M. T L.S. L, L. L, L, L, P/M O.S. T /B.R. /O.M. 23. 0 69 .9 7. 1 5. 1 5 1 .59 -0. 1 5 0. 4 30. 0 62 .2 7. 8 5. 18 1 .89 -0. 29 0. 5 17. 1 80 .4 2. 5 5. 46 1 .43 -0. 56 0. 68 30. 5 64 .8 4. 7 5. 0 1 .79 -0. 39 0. 47 81 . 2 17 .8 1 . 0 3. 5 1 .35 0. 1 5 0. 6 38. 9 56 .3 4. 8 4. 76 2 . 1 1 - o . 45 0. 47 48. 7 49 .6 • 0 . 9 4. 9 1 .43 - o . 19 0. 46 58. 1 40 .0 1 . 9 4. 1 7 2 .46 - o . 22 0. 39 60. 4 39 .2 0. 4 3. 97 1 .78 0. 22 0. 37 38. 2 56 . 1 5. 7 5. 08 1 .84 -0. 47 0. 45 18. 5 78 .4 3. 1 5. 54 1 .49 -0. 54 0. 69 20. 2 77 .5 2. 3 5. 58 1 .58 -0. 62 0. 61 25. 7 73 .4 0. 9 5. 37 1 .76 - o . 72 0. 45 30. 2 68 .3 1 . 5 5. 2 1 .51 -0. 64 0. 41 83. 6 16 .2 0. 2 3. 44 1 .32 0. 21 0. 64 27. 0 72 .2 0. 8 5. 45 1 .61 -0. 69 0. 41 44. 8 51 .3 3. 9 5. 07 1 .87 -0. 35 0. 42 47. 9 51 .3 0. 4 4. 96 1 .43 -0. 1 1 0. 41 17. 6 80 .8 1 . 5 5. 45 1 .48 -0. 7 0. 73 46. 5 53 . 1 0. 4 5. 05 1 .42 -0. 29 0. 46 49. 1 49 .6 0. 3 4. 90 1 .30 -0. 37 0. 47 48. 1 50 .9 0. 9 4. 84 1 .89 -0. 37 0. 38 5 . 0 . 0 48 . 1 1 . 9 3. 64 2 .23 0. 67 0. 4 28. 5 68 .8 2. 7 5. 1 3 1 .91 -0. 74 0. 48 0. 0 97 .6 2. 4 6. 5 0 .52 -0. 25 0. 56 2. 1 95 .6 2. 3 6. 31 0 .87 -0. 35 0. 52 76. 8 22 .7 0. 5 3. 73 0 .91 0. 1 5 0. 57 15. 6 82 .0 2. 4 5. 93 0 .95 - o . 54 0. 61 17. 9 80 .6 1 . •5 5. 86 1 . 1 9 -0. 24 0. 4 18. 5 80 .6 1 . 5 5. 63 .1 .35 - o . 45 0. 66 89. 8 9 .4 0. 8 2. 85 1 . 36 0. 5 0. 58 90. 2 9 .7 0. 1 0. 34 2 .56 0. 34 0. 45 144 Table V.1 (cont.) Core S t r a t i g r a p h i c Sand S i l t Clay Mz ox Ski KG' un i t (%) (<f>) (0) L.S. 0. 0 96. 3 3. 7 6. 54 0 .92 - o . 40 0. 52 •L. S. 25. 0 72. 9 2. 1 5. 19 1 .69 - o . 71 0. 5 L.S. 26. 3 63. 2 10. 5 5. 44 2 .17 - o . 1 9 0. 53 L.S./O.M. 12. 2 78. 3 9. 5 5. 76 1 .41 - o . 47 0. 53 P/M 26. 3 63. 5 10. 2 5. 38 2 . 13 - o . 18 0. 42 L.S./O.M. 37. 0 58. 1 8. 9 5. 01 1 .03 - o . 31 0. 41 O.S. 75. 0 23. 0 2. 0 1 . 6 3 .36 0. 18 0. 48 L.S./C.Sand 39. 9 56. 8 3. 3 4. 39 2 .0 - o . 51 0. 51 C.G. 73. 1 25. 0 1 . 9 3. 25 1 .52 0. 32 0. 38 L.S./C.Sand 50. 6 47. 9 1 . 5 4. 05 1 .73 - o . 69 0. 55 M 25. 4 72. 7 1 . 9 5. 1 7 1 .23 0. 07 0. 75 L.S./C.Sand 67. 6 32. 8 2. 8 3. 35 2 .51 0. 1 5 0. 47 O.S. 86. 5 12. 6 0. 9 1 . 22 2 . 14 0. 4 0. 5 N.B. L . S . = l a c u s t r i n e s i l t s ; B.R.=Bridge R i v e r ash; O.M.=organic matter; P=peat; M=Mazama ash; O.S=oxidised sands; T = t i l l ; C.Sand=coarse sands; C.G.=coarse g r a v e l . 145 Table V.2 T o t a l element content of the s t r a t i g r a p h i c h o r i z o n s of the master c o r e . Element 1 2 3 4 5 6 7 8 9 1 0 A l 6.17 4.0 4.37 5.95 2.94 3.55 4.07 3.31 4.30 5.20 Ba 0.04 0.03 0.04 0.05 0.02 0.03 0.03 0.02 0.03 0.05 Ca 1.63 1.06 0.66 1.32 0.78 0.97 1.11 0.83 1.19 1.16 Fe 2.38 1.64 0.88 1.62 1.11 1.11 1.5 1.14 1.61 1.44 Mg 1.12 0.8 0.21 0.77 0.56 0.68 1.67 0.48 0.82 0.68 Mn 0.05 0.04 0.02 0.04 0.03 0.03 0.04 0.03 0.04 0.03 Na 5.67 3.52 7.33 3.26 6.43 4.34 5.13 4.02 4.31 4.61 P 3.73 2.5 5.59 1.07 5.76 3.0 3.87 2.85 2.95 2.67 S i 23.2 16.0 19.6 24.8 16.0 16.8 18.1 17.7 20.3 22.4 Sr 0.03 0.02 0.01 0..03 0.01 0.02 0.02. 0.-02 .0.02 0.03 T i 0.32 0.22 0.16 0.23 0.16 0.19 0.21 0.15 0.24-0.21 N.B. 1 = l a c u s t r i n e s i l t s ; 2 = l a c u s t r i n e s i l t s ; 3 = l a c u s t r i n e s i l t s e n r i c h e d with Bridge R i v e r ash; 4 = l a c u s t r i n e s i l t s ; 5= l a c u s t r i n e s i l t s e n r i c h e d with o r g a n i c matter; 6=peat; 7=peat e n r i c h e d with Mazama ash; 8=peat; 9 = l a c u s t r i n e s i l t s and organic matter; 10=ti11. 146 Appendix VI X.R.D. diffractograms Sample 1 K saturated a i r dried K saturated - 550 C Mg saturated a i r dried V Mg saturated & g l y c o l . N.B. Ka = k a o l i n i t e ; V = two forms of vermiculite discussed in section 5.1.5; A = amphibole; Q = quartz; F = feldspar; M = mica; C = c h l o r i t e . 14 7 Sample 2 K s a t u r a t e d a i r d r i e d K s a t u r a t e d - 550 C Mg s a t u r a t e d . & g l y c o l . 14 8 Sample 3 K s a t u r a t e d a i r d r i e d 14 9 Sample 4 K s a t u r a t e d a i r d r i e d M g . s a t u r a t e d & g l y c o l . Ka K 150 Sample 5 151 Sample 6 152 Sample 7 K s a t u r a t e d a i r d r i e d K s a t u r a t e d - 300 C K s a t u r a t e d - 550 C Mg s a t u r a t e d a i r d r i e d Mg s a t u r a t e d & g l y c o l . 153 Sample 8 K s a t u r a t e d a i r d r i e d K s a t u r a t e d - 300 C K s a t u r a t e d - 550 C Mg s a t u r a t e d a i r d r i e d Mg s a t u r a t e d & g l y c o l . 154 Sample 9 

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