Site Investigations at East Three: 1954

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Site Investigations at East Three: 1954

SITE INVESTIGATIONS AT EAST llHREE: 1954

by

R . J . E . Brown, G . H . J o h n s t o n , and J . A . P i h l a i n e n

_--P- -.-.-s,- " ..,,.

I

NA'T IONAL RESEARCH COUNCIL

i

CANADA I f

I

!

I

Y I P ? 1 i ? i 1 4

i

4

i

I

i

I

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I

[

1

f Ottawa December

1954

--

A N A L Y Z E D ( p r e p a r e d f o r t h e Department of Northern A f f a i r s and N a t i o n a l ~ e s o u r c e s ) Report No.

57

of t h e D i v i s i o n of B u i l d i n g Research

PREFACE

During t h e summer of 1953, t h e Permafrost Research S t a t i o n of t h e D i v i s i o n of B u i l d i n g Research c a r r i e d out an e x t e n s i v e i n v e s t i g a t i o n of s o i l conditions

a t Aklavik, N .W .T. T h i s program was c a r r i e d out j o i n t l y w i t h t h e Department of Northern p f f a i r s and N a t i o n a l Resources I n c o n j u n c t i o n w i t h t h e c o n s t r u c t i o n of a ten-room s c h o o l and a n e i g h t - a p a r t m e n t t e a c h e r a g e . The i n v e s t i g a t i o n s r e v e a l e d t h a t t h e s o i l s i n Aklavik a r e s i l t s and f i n e sands w i t h e x t r e m e l y h i g h i c e c o n t e n t s making

c o n s t ~ u c t i o n c o s t l y . I n view of a l a r g e a n t i c i p a t e d

Government c o n s t r u c t i o n program a t Aklavik, t h i s i n f o r m a t i o n formed p a r t of t h e b a s i s f o r c o n s i d e r i n g t h e r e l o c a t i o n of t h e town,

A t t h e r e q u e s t of t h e Department of Northern A f f a i r s , pe-sonnel from t h e Permafrost Research S t a t i o n , t o g e t h e r w i t h o t h e r i n t e r e s t e d F e d e r a l d e p a r t m e n t s , formed a survey team t o g a t h e r f i e l d i n f o r m a t i o n d u r i n g 1954 on t h e p o s s i b i l i t y of l o c a t i n g a more s u i t a b l e t o w n s i t e i n t h e v i c i n i - t y of t h e Mackenzie R i v e r d e l t a . M r , C.L. M e r r i l l , Department of Northern A f f a i r s and N a t i o n a l Resources, was l e a d e r of t h e

t eam

.

A e r i a l photographs of t h e Mackenzie D e l t a were assembled i n t o u n c o n t r o l l e d mosaics by t h e D i v i s i o n d u r i n g J a n u a r y , 1954. Analyses of t h e photographs l o c a t e d s i x p o t e n t i a l t o w n s i t e a r e a s and t h e s e were i n v e s t i g a t e d i n t h e f i e l d from A p r i l t o J u l y . A f i e l d a p p r a i s a l of t h e p o t e n t i a l s i t e s e s t a b l i s h e d one on t h e e a s t s i d e of t h e Mackenzie R i v e r d e l t a (known as "East T h r e e " ) as t h e mast s a t i s f a c t o r y and f u r t h e r s o i l i n v e s t i g a t i o n s were c a r r i e d out t h e s e d u r i n g August and September.

The purpose of t h i s r e p o r t fs t o make a v a i l a b l e t o t h o s e a c t i v e l y engaged on t h e Aklavik R e l o c a t i o n P r o j e c t , a r e c o r d of d a t a c o l l e c t e d by Permafrost Research S t a t i o n p e r s o n n e l a t t h i s most s u i t a b l e of t h e s f t e s , E a s t Three. The r e p o r t i s concerned mainly w i t h s o l 1 and p e r m a f r o s t c o n d i t i o n s . I n f o r m a t i o n on o t h e r p h y s i c a l a s p e c t s of E a s t Three i s i n c l u d e d because of i t s i n t e r - r e l a t i o n s h i p w i t h t h e s o i l and p e r m a f r o s t c o n d i t i o n s o r because t h e d a t a were c o l l e c t e d on r e q u e s t by

"Permafrost" p e r s o n n e l .

Ottawa,

TABLE

OF CONTENTS Page 1

.

Introduction

...

1

...

.

.

2 Exploratory Field Work Reconnaissance 3

3

.

Exploratory Field Work . Soil Sampling

...

3

3.1 Borehole Locations

...

3

3 . 2 Test Pits

...

3

3.3 3oj.l Samples

...

4

3.4 Presentation of Data by Physical Units

...

4

...

.

4.

Topographic Divisions Northern Flats

5

4.1 Relief

...

5

4 . 2 Drainage

...

5

4 0 3 Vegetation

...

6

4.4

Soils and Permafrost

...

6

5

.

Topographic Divisions

.

North Central Elevated Flats

...

6

5.1 Relief

...

6

5.2

Drainage

...

7

5.3

Vegetation

...

8

5.

4

Soils and Permafrost

...

9

...

.

6

.

Topographic Divisions South Centra 1 Lowland 11 6.1 Relief

...

11

6 0 2 Drainage

...

11

6.3 Vegetation

...

11

6

Soils and Permafrost

...

11

7

.

Topographic Divisions . South Central Ridges

...

12

...

7.1 Relief 12 7.2 Drainage

...

12

...

7.3

vegetation 12

...

7.4

Sof 1s and Permafrost 13

8

.

Topographic Divisions . Long Lake Flats and Ridges* 13 8.1 Relief

...

13

8.2 Draf nage

...

14

8.3

Vegetation

...

14

8.4

Soils and Permafrost

...

15

9.

Topographic Divisions . Eastern Upland . . . o ~ o o o . o ~ . 16 9 - 1 Relief

...

16

9 . 2 Drainage

...

17

9.3

Vegetation

...

17

9.4

Soils and Permafrost

...

18

.

....

.

TABLE OF CONTENTS ( ~ o n t i n u e d )

Appendix A

-

Break-up Observations

A 1, General D e s c r i p t i o n of I c e Movement

A 2 , D a i l y Log

A 3. Water Level Graph

Appendix B

-

T e s t P i t Logs and S o i l T e s t Summary S h e e t s B 1, S o i l Type B 2 , Gsaphisal S o i l Symbols B

3 0

I c e S e g r e g a t i o n i n S o i l s B

4 ,

Moisture Content ( I c e c o n t e n t ) B

5.

Grain S i z e s B

6,

P l a s t i c i t y B

7.

S p e c i f i c G r a v i t y B 8, F i e l d Unit Weight B 9 . Organic T e r r a i n

SITE INVESTIGATIONS AT EAST THREE: 1954

by R . J .E. Brown, G .H. J o h n s t o n , and J .A. P i h l a i n e n

The Mackenzie R i v e r d e l t a i s approximately 100 m i l e s l o n g and 50 m i l e s wide c o v e r i n g a n a r e a of more t h a n 5,000 s q u a r e m i l e s . Unlike a t y p i c a l d e l t a which f a n s o u t from i t s

s o u r c e , t h i s one i s long and narrow. The shape of t h e d e l t a i s c o n t r o l l e d by t h e a d j a c e n t upland and c u r v e s from t h e s o u t h t o t h e n o r t h w e s t . The west s i d e i s confined by t h e Richardson Mountains, a n o r t h e r n e x t e n s i o n of t h e Rocky Mountains. These mountains, which extend t o t h e northwest a r e predominantly

sandstone and s h a l e of Cretaceous Age, The e a s t s i d e i s confined by t h e Caribou H i l l s , morainic h i l l s , and e x t e n s i v e exposures of Palaeozoic l i m e s t o n e s , s a n d s t o n e s , and s h a l e .

A t t h e s o u t h e r n e x t r e m i t y of t h e d e l t a n e a r P o i n t S e p a r a t i o n , t h e Mackenzie R i v e r d i v i d e s i n t o t h r e e major

c h a n n e l s . The main o r middle channel f l o w s through t h e middle of t h e d e l t a , The E a s t Channel branches from t h e Middle Channel and f l o w s down t h e e a s t s i d e . The Peel C h a n n e l b r a n c h e s f r o m t h e Middle Channel and f l o w s down t h e west s i d e . Approximately

half-way t o t h e c o a s t , t h e Peel Channel becomes t h e West Channel. Aklavik i s s i t u a t e d on a s h a r p bend i n t h e Peel Channel t h r e e m i l e s upstream from t h e beginning of t h e West Channel. E a s t Thpee (68O 211 N , , 1 3 3 O 4 4 ' W . ) i s l o c a t e d on t h e E a s t Channel about t h e same l a t i t u d e a s Aklavik, It i s 35 m i l e s by a i r and 70 m i l e s by w a t e r from t h e s e t t l e m e n t ,

A t E a s t Three t h e r e i s an e x t e n s i v e a r e a of g l a c i a l l y d e p o s i t e d m a t e r i a l d i s p l a y i n g a v a r i e t y of landforms, South of E a s t Three a r e e x t e n s i v e a r e a s of Palaeozoic l i m e s t o n e s ,

sandstone^ and s h a l e s , which b o r d e r t h e e a s t s i d e of t h e

Mackenzie D e l t a . T h i s bedrock o u t c s ~ p s a s s t e e p b l u f f s on t h e n o r t h s h o r e of Dolomite Lake a few m i l e s e a s t of t h e s o u t h end of E a s t Three, These s e d i m e n t a r i e s a p p e a r t o d i p t o t h e n o r t h under t h e g l a c i a l d e p o s i t i o n and may e x e r t some t o p o g r a p h i c c o n t r o l on t h e landforms.

Fsom t h e edge of t h e d e l t a t h e a d j a c e n t upland r i s e s g e n t l y f o r 1 t o 1$ m i l e s . T h i s r e l a t i v e l y low a r e a i s bounded on t h e e a s t by a h i g h i n t e r i o r upland s i s l n g over 150 f e e t .

E a s t Three i s l o c a t e d on t h i s lower l e v e l of t h e country a d j a c e n t t o t h e d e l t a , I t s e a s t e r n boundary is d e l i n e a t e d by t h e s t e e p s l o p e t o t h e h i g h e r l a n d lhihich r o u g h l y p a r a l l e l s t h e edge of t h e d e l t a . The E a s t Three a r e a e x t e n d s g e n e r a l l y i n a northwest-to- s o u t h e a s t d i r e c t i o n on which t h e lar,dEcms a r e o r i e n t e d i n a n o r t h w e s t - t o - s o u t h e a s t and w e s t - t o - e a s t d i r e c t i o n , The g e n e r a l w e s t - t o - e a s t o r i e n t a t i o n of t h e l a k e s er~~plhasfzes t h i s c o n d i t f o n .

The r e l i e f of t h e a r e a i s one of f l a t s a t varying e l e v a t i o n s , g e n t l e u n d u l a t i o n s s e p a r a t e d by shallow swales, rounded k n o l l s , hmnocky h i l l s , and r i d g e s of v a r y i n g h e i g h t s and l e n g t h s .

E a s t Three i s d r a i n e d t o t h e west and northwest by s t r e a m s which emanate from deep g u l l i e s i n t h e h i g h i n t e r i o r upland. The d r a i n a g e i s c o n t r o l l e d by t h e r e l i e f e s p e c i a l l y i n t h e s o u t h p a r t of t h e a r e a where t h e s t r e a m s flow i n p a r a l l e l c o u r s e s between t h e r i d g e s . As a r u l e t h e r i d g e s , k n o l l s , and 1~'1dulations a r e w e l l d r a i n e d w h i l e some of t h e r e l a t i v e l y lower f l a t s a r e n o t ,

Spruce and b i r c h a r e t h e dominant t r e e t y p e s w i t h s e c o n d a ~ y s t a n d s of willow and a l d e r , The ground i s g e n e r a l l y h l m o c k y w i t h a v e g e t a t i v e c o v e r c f ground b i r c h , r e i n d e e r and

sphagqm moss, g r a s s t u s s o c k s , Labrador t e a 2nd b e r r y p l a n t s . B'rch predominates on t h e s o u t h - f a c l n g s l o p e s of t h e landforms

and on w e l l - d r a i n e d a r e a s . Spruce p-edaminates on t h e n o r t h - f a c i n g s l o p e s w h i l e s t u n t e d s p r u c e , willow, and a l d e r a r e found on more p o o r l y d r a i n e d a r e a s . Few t r e e s grow on low f l a t a r e a s e x c e p t a l o n g s t r e a m c o u r s e s where t h e ~ e a r e dense t h i c k e t s of willow and a l d e r .

A t E a s t Three, f r o z e n ground i s encountered from

6

i n c h e s t o

4

f e e t

3

i n c h e s below t h e ground s u r f a c e and i s

covered by l i v i n g o r g a n i c m a t e r i a l 3 i n c h e s t o

9

i n c h e s i n d e p t h . S o i l s range from g l a c i a l t i l l ( s t o n y . s l L t y c l a y s w i t h v a r y i n g amounts of organic m a t e r i a l ) t o g ~ a v e l a , w l t h t h e f i n e - g r a i n e d mate-pi21 d e p o s j - t s b e i n g of g r e a t e ? exrsrt. The l a r g e s t d e p o s i t s of c o a r s e - g r a i n e d m a t e r i a l s ( s a n d s and g r a v e l s ) a r e found on t h e n o r t h e r n p o r t i o n of t h e s i t e immediately n o r t h of Boot Lake. T h i s a r e a i s thought t o be s u i t a b l e a s a t o w n s i t e l o c a t i o n w i t h Toom r o r expansion. Gravel d s p c a l t s a l o n g the east bank o t Tw.i.n Lake w i l l p r o v i d e much m a t e r l a l f o s f i l l , F u r t h e r deposS.tz. o? cosrse-graLned m a t e r i a l o c c u r , t o a l e s s e r e x t e n t , on and a d j a c e n t t o t h e proposed l o c a t i o n f o ~ t h e a i r s t y i p in t h e 3outhern p o r t i o n of

t h e a r e a j u s t n o r t h of Long Lake.

F i n e r g r a i n e d s o i l s ( s t a n y s l l t c l a y s ) a r e found over t h e r e s t of t h e s l t e a r e a -- i n t h e r i d g e s and i n t h e lower a r e a s . They a l s o occur on p a r t of the propcsed a i r s t r i p a r e a . While t h e s e s o f l s a r e l e s s d e s i r a b l e a s f o u n d a t i o n m a t e r l a l no

s e r i o u s t r o u b l e should o c c u r i f p r o p e r c a r e i s e x e r c i s e d . The l i m e s t o n e o u t c r o p s on Dolomite Lake t o t h e e a s t could p r o v i d e s u f f i c i e n t good a g g r e g a t e f o ~ c o n c r e t e ,

Ice s e g r e g a t i o n i n t h e g r a v e l s does not a p p e a r t o be s i g n i f i c a n t . However, t h e i c e phase i n t h e s i l t s and s i l t c l a y s r a n g e s from t h i n l e n s e s t o d e p o s i t s up t,o 1 5 i n c h e s i n t h i c k n e s s .

S o i l and p e r m a f r o s t c o n d i t i o n s v a r y from p l a c e t o p l a c e over t h e E a s t Three a r e a . Some p o r t l ' m s of t h e a r e a w i l l n o t prove s u l t a b l e f o r c o n s t r u c t i o r ~ p u r p o s e s , o t h e r s w i l l be found t o be w e l l s u i t e d . On t h e whole, however, t h e E a s t T h r e e a r e a ahould prove s a t i s f a c t o r y ,

It was t h e o n l y one of t h e s i t e s i n v e s t i g a t e d which had a p p r e c i a b l e a r e a s of c o a r s e - g r a i n e d s o i l s . With c a r e f u l s i t e planning a l l t h e o b j e c t i o n s t o t h e p r e s e n t s i t e of

Aklavik should be a b s e n t when t h e new town i s b u i l t a t East Three.

2 . E x ~ l o r a t o r v F i e l d Work

-

Reconnaissance

I n view of t h e s h o r t f i e l d s s a s o n and t h e l a r g e a r e a s t h a t had t o be i n v e s t i g a t e d , e x p l o r a t o r y s o i l sampling was

ca,rried out a t r e p r e s e n t a t i v e p o r t i o n s of each p o t e n t i a l s i t e . A c c o r d i n g l y . .-econnaissance surveys, by a i r and f o o t

,

preceded e x p l o r a t o r y d r i l l i n g and s o i l sampling,

3. E x p l o r a t o r y F i e l d Work

-

S o i l Samp1ixl.g 3 . 1 Aorehole Locations

A t E a s t Three, a s o i l expoau-e a t Twin Lake ( ~ i g .

7 )

suggested t h e presence of g r a n u l a r m a t e r i a l s i n t h e n o r t h e r n p o r t i o n of t h e s i t e . 'I'wo subsequen: d ~ i l l h o l e s confirmed t h e b e l i e f t h a t a n a r e a l a r g e enough f o r a t o w n s i t e had been l o c a t e d . S o i l sampling i n f r o z e n g r a v e l i s n o t p o s s i b f e w i t h t h e d ~ i l l r i g used and t h e h o l e s were abandoned a t t h % 13-foot d e p t h s b e f o r e any damage could be caused t o t h e Light r i g .

3.2 Test P i t s

Having proved t h e presence of g r a n u l a r m a t e r i a l s , twenty-four t e s t p i t s were l o c a t e d a t anticipated c o n s t r u c t i o n a r e a s of t h e s i t e i n a n a t t e m p t t o map and s m p l e t h e s o i l s . T e s t p i t s weye n o t excavated on t h e 0 t ~ 5 . e - a r e a s because t h e

ground appeased t o be less s u i t a b l e f o r c o n s t ~ u c t i o n and because of t h e l a c k of time d u r i n g t h e 1954 F i e l d season.

While f o u n d a t i o n s normally extend t o d e p t h s below

5

f e e t , e n g i n e e r i n g problems i n a r e a s bccur w i t h i n t h e f i r s t 5 f e e t . Thus t h e m a j o ~ i t y of t h e t e s t p i t s on t h e E a s t Three s i t e were excavated t o a d e p t h of about

5

f e e t

a l t h o u g h s e v e r a l were continued below this d e p t h . The s u r f a c e dimensions of t h e t e s t p i t s averaged

5

by 7 f e e t .

A t f i r s t t h e t e s t p i t s were advanced by merely removing t h e thawed s o i l p e r i o d i c a l l y . I n o r d e r t o b r i n g t h e t e s t p i t s t o a d e p t h of a t l e a s t 5 f e e t b e f o r e t h e season ended, t h e remaining few f e e t i n o u t s t a n d i n g p i t s were picked by l o c a l l a b o u r . A l l s o i l samples were shipped ts Noman Wells where t h e y were t e s t e d a t t h e s o i l mechanics l a b o r a t o r y of t h e Permafrost Research S t a t i o n .

3 . 3

S o i l Samples

R e p r e s e n t a t i v e samples f o r i d e n t i f i c a t i o n by s o i l t e s t i n g were t a k e n wherever t h e r e was a n a p p a r e n t change I n s o i l t y p e . "Moisture'! o r , t o be more c o r r e c t , ' ' i c e " c o n t e n t samgles were t a k e n e v e r y f o o t i n f r o z m g r ~ a n d where p o s s i b l e . Samples f o r " i c e " c o n t e n t determinatrf-clns sse e x t r e m e l y d i f f i c u l t

i f n o t i m p o s s i b l e t o o b t a i n i n c o a r s e - g a i n e d s o i l s .

The form of i c e s e g r e g a t i o n i n t h e s o i l s was of t h r e e b a s i c t y p e s :

(1) i c e which c o a t e d i n d i v i d u a l p a r t i c l e s ( w e l l bonded m a t e r i a l ) but was not n e c e s s a r i l y G i s c e r n i b l e t o t h e

eye ;

( 2 ) i c e l e n s e s r e g u l a r l y ( h o r i z o n t a l ) o r i r r e g u l a r l y ( h o r i z o n t a l , v e r t i c a l and d i a g o n a l l y t o g e t h e r )

o r i e n t e d i n t h e s o i l . These Tenses, dykes o r - v e i n s ranged i n s i z e from h a i r l i n e [H.L.) t o 2 i n c h e s ;

( 3 )

"massive" i c e i n t h e s o i l : a r b i t r a r i l y any i c e

f o r m a t i o n s x c e e d i n g 2 in:.hes i:-A t h i c k n e s s was

c a l l e d "massive". These c c u l d b e , and were, o r i e n t e d i n a l l d i r e c t i o n s ,

An a e r i a l photograph of E a s t Three ( F i g . 1) shows t h e l o c a t i o n s of t h e v a r i o u s t e s t p i t s and b o s e h o l e s . A l o g of each t e s t p i t and a summary of s o i l t e s t i n g r e s u l t s from each p i t i s i n c l u d e d i n Appendix E.

3.4 P r e s e n t a t i o n of Data by P h y s i c a l LJnits

F o r t h e s a k e o f convenience and $ 6 s i m p l i f y t h e

p r e s e n t a t i o n of m a t e r i a l , t h e E a s t T h x e a x a h a s been d i v i d e d i n t o s e v e r a l t o p o g r a p h i c d l . v i s i o n s , Althoa.lgh t h e s e i s much v a r i e t y i n t h e landforms w i t h i n t h e area, i t h a s been p o s s i b l e t o d e l i n e a t e s i x d i v i s i o n s on t h e bas:s o f t h e c o n f i g u r a t i o n of t h e t e r r a i n . One of t h e s e divisions, t h e i n t e r l o r upland, forms t h e e a s t boundary of E a s t Three. T h e s i x d i v i s i o n s a r e :

Northern F l a t s , North C e n t r a l E l e v a t e d F P % t s u South C e n t r a l Lowland, South C e n t r a l Ridges, Long L ~ k e Fl.ats and Ridges, and E a s t e r n Upland. The f i r s t f-L,ve d i v i s i o r i s aFe l i s t e d i n o r d e r from n o r t h t o s o u t h , w h i l e t h e E a s t e r n Upland forms t h e e a s t e r n boundary of t h e s i t e a r e a . The name g i v e n t o e a c h d i v i s i o n d e s c r i b e s g e n e r a l l y i t s t o p o g r a p h i c appearance and p o s i t i o n w i t h r e s p e c t t o t h e o t h e r d i v i s i o n s . I n some c a s e s t h e t i 5 l e d e s c r i p t i o n can r e f e r o n l y t o t h e n u c l e u s of' t h e d i v i s i o n s i n c e most have i n t e r m e d i a t e a r e a s of t r a n s i t i o r l w i t h a d j z c e n t d i v i s i o n s . I n t h e s e i n s t a n c e s , t h e boundary i s a r b f t s a s l l y d e l i n e a t e d o n l y f o r t h e puypose of p r e s e n t i n g d a t a . ,

F i e l d d a t a w i l l be p r e s e n t e d under t h e s e s i x t o p o g r a p h i c d i v i s i o n s . A d e s c r i p t i o n of t h e topography, d r a i n a g e , and v e g e t a t i o n of e a c h d i v i s i o n i s p r e s e n t e d t o p r o v i d e a n

i n t r o d u c t i o n t o and t o c l a r i f y t h e s o i l s and p e r m a f r o s t

c o n d i t i o n s which a r e i n t e r - r e l a t e d wit.h t h e s e aforementioned f a c t o r s . An a t t e m p t h a s been made t o s i m a r i z e a l l t h i s

i n f o r m a t i o n on a n a e r i a l photograph and maps ( ~ i g s . 1 and 2 1 ) . D e t a i l e d i n f o r m a t i o n from which t h e maps were drawn i s i n t h e a p p e n d i c e s .

9.

P f v f s i o n s

-

Northerr?. F l a t s 4 . 1 R e l i e f

The Northern F l a t s a r e t h e northernmost d i v i s i o n of E a s t Three. It i s a f l a t a r e a r i s i n g g e n t l y from t h e E a s t Channel and Mackenzie D e l t a which bounds t h e a r e a on t h e w e s t . To t h e e a s t t h e ayea i s bounded by t h e west s l o p e of t h e E a s t e r n Upland which r i s e s s h a r p l y from t h e s e f l a t s . To t h e n o r t n , t h i s upland s l o p e c u r v e s t o t h e northwest tgward t h e d e l t a and

e n c l o s e s t h e a r e a a p p r o x i m a t e l y

3$

m i l e s n o r t h of Twin Lake. To t h e s o u t h , t h e s e n o r t h e r n f l a t s mepge i n t o t h e u n d u l a t i n g upper l e v e l s of t h e North C e n t r a l E l e v a t e d F l a t s . There i s a low-lying e x t e n s i o n of t h e s e f l a t s e x t e n d i n g t o t h e ~ 0 ~ 1 t h between t h e

North C e n t r a l E l e v a t e d F l a t s and E a s t e r n Upland which i s t e r m i n a t e d by Hidden Lake.

Tne g e n e r a l appearance of a f l a t a r e a r i s i n g g e n t l y from t h e E a s t Channel i s i n t e r r u p t e d by two low rounded k n o l l s , e a c h r i s i n g a p p r o x i m a t e l y 30 f e e t above t h e g e n e r a l l e v e l of t h e f l a t s . These k n o l l s a r e one m i l e a p a r t and a r e s e p a r a t e d by one

of t h e two major stream c o u r s ~ s which d r a l n t h e a r e a . The n o r t h e r n k n o l l i s a c t u a l l y a low rounded r i d g e o n e - t h i r d of a m i l e long

having a z o r t h w e s t - t o - s o u t h e a s t o r i e n t a t i o n . The only o t h e r l o c a l r e l i e f 1s some v e r y g e n t l e undulations a t t h e west edge of t h e f l a t s a l o n g t h e East Channel.

4 . 2 Drainage

Because of t h e g e n t l e downgrade from east-to-west t o t h e d e l t a , s u r f a c e d r a i n a g e i s a c r o s s t h e f l a t s i n t h i s downslope d i r e c t i o n . There a r e two main s t r e a m s a p p r o x i m a t e l y 1* m i l e s a p a r t emanating from deep V-shaped g u l l i e s i n t h e E a s t e r n Upland t o t h e e a s t , which f l o w a c r o s s t h e f l a t s t o t h e d e l t a , p r o v i d i n g d r a i n a g e f o r most of t h e a r e a . It a p p e a r s t h a t t h e l o s s i n v e l o c i t y when t h e s t r e a m s emerge from t h e g u l l i e s h a s been s u f f i c i e n t t o

b u i l d up e x t e n s i v e " a l l u v i a l f a n - l i k e " d e p o s i t s . These f a n - l i k e a r e a s which merge i m p e r c e p t i b l y w i t h t h e g e n e r a l f l a t a r e a , a r e more c l e a r l y d e f i n e d from t h e a i r . The main flow of w a t e r o c c u r s d u r i n g s p r i n g breakup and t h e s t r e a m s a r e reduced t o a t r i c k l e i n t h e summer. As a r e s u l t , downcutting i s slow and t h e s t r e a m eoupses a r e only a few f e e t i n d e p t h and w i d t h .

To t h e s o u t h of t h e s e two major s t r e a m s a r e two s m a l l e r c r e e k s emanating from t h e E a s t e r n Upland.

4 . 3 V e g e t a t i o n

Throughout t h e f l a t s , e x c e p t on t h e a l l u v i a l f a n - l i k e a r e a of t h e two major s t r e a m s , s c a t t e r e d growths of w h i t e s p r u c e predominate. Low willow and a l d e r scrub,and ground b i r c h ? ~ p t o

4

f e e t h i g h i n s c a t t e r e d clumps form t h e underbrush. I n t h e e x t e n s i o n of t h e f l a t s between t h e North C e n t r a l E l e v a t e d F l a t s and t h e E a s t e r n Upland t h e r e a r e dense s t a n d s of s p i n d l y s p r u c e w i t h a willow and a l d e r underbrush. The ground v e g e t a t i o n i s predominantly r e i n d e e r moss and g r a s s t u s s o c k s growing on

hummocks 2 f e e t h i g h . Other ground p l a n t s i n c l u d e Labrador t e a and v a ~ i o u s b e r r y p l a n t s .

On t h e a l l u v i a l f a n - l i k e d e p o s i t s of t h e two major s t r e a m c o u r s e s , t h e v e g e t a t i o n i s s c r u b willow and a l d e r i n

s c a t t e r e d s t a n d s i n t e r m i x e d w i t h ground b i r c h . The ground c o v e r i s r e i n d e e r moss and g r a s s . There a r e many polygonal c r a c k s and f r o s t b o i l s .

B i r c h up t o 25 f e e t h i g h w i t h s c a t t e r e d s p r u c e up t o 3 O f e e t h i g h a r e found on t h e s o u t h - f a c i n g s l o p e s of t h e low k i i o l l and ~ i d g e . On t h e n o r t h - f a c i n g s l o p e s t h e r e i s mixed s p r u c e and b i r c h . The d i a m e t e r s of t h e t r e e t r u n k s a v e r a g e 6 t o 9 i n c h e s a t b r e a s t - h e i g h t .

4 . 4 S o i l s and Permafrost

The Northern F l a t s were a p p r a i s e d i n t h e f i e l d as

u n s u i t a b l e f o r c o n s t r u c t i o n and t h u s o n l y a c u r s o r y examinatior* w a s made. No b o r e h o l e s o r t e s t p i t s were l o c a t e d i n t h i s a r e a

s o t h a t s o i l s and p e r m a f r o s t i n f o r m a t i o n i s l i m i t e d t o i n f e r e n c e from v e g e t a t i o n and t e r r a i n n o t e s .

The e x t e n s i v e a l l u v i a l f a n - l i k e d e p o s i t s emanating f r m t h e F a s t e r n Upiand a r e t3. '?Ti" t o be f i n e - g r a i n e d s o i l s , silts and s i l t c l a y s , w i t h v a r y i n g amounts of o r g a n i c m a t e r i a l .

I n t e n s i v e f r o s t a c t i o n as evidenced by polygonal c r a c k s and f r c s t b o i l s i n t h e a r e a a r e g e n e r a l l y i n d i c a t i v e of f i n e r - g r a i n e d

m a t e r i a l s . The d e p t h t ( c ! f r o z e n ground v a r i e s from

3

f e e t 2.3 areas

~ ~ 7 3 t h l i t t l e v e g e t a t i v e coTrer, t o 1 2 o r 18 i n c h e s i n moss eovered a y e a s ( h u g u s t 27 1.954) 8

5 , Topographic D i v i s i o n s

-

North C e n t r a l E l e v a t e d F l a t s 5 . 1 R e l i e f

T h i s i s one of t h e most c l e a r l y d e f i n e d d i v i s i o n s of

t h e s i t e a r e a . To t h e n o r t h , j u s t n o r t h of Twin Lake, a r e t h ~ Northern F l a t s . To t h e e a s t i s t h e E a s t e r n Upland r i s i n g from t h e e a s t s h o r e of Hidden Lake. To t h e s o u t h i s Boot Lake V a l l e y which p r o v i d e s t h e most d i s t i n c t boundary l i n e . To t h e west i s t h e E a s t Channel and Mackenzie D e l t a .

There a r e two g e n e r a l l e v e l s which a r e e l e v a t e d above t h e l e v e l of t h e d e l t a and t h e Northern F l a t s . They a r e n o t a s h i g h a s t h e E a s t e r n Upland, however9 but a c t a s a s e r i e s of s t e p s from t h e d e l t a t o t h i s h i g h a r e a ,

The lower l e v e l i s a p p r o x i m a t e l y 60 f e e t above Boot Lake and t h e l e v e l of t h e d e l t a . The s o u t h e r n s l o p e down t o t h e l a k e i s approximately 20 d e g r e e s . F-am t h e t o p of t h i s s l o p e t h e r e i s a n almost i m p e r c e p t i b l e d o w n g r ~ d e t o t h e n o r t h .

There a r e t h r e e p a r a l l e l rounded r i d g e s and k n o l l s whose t o p s a r e a t t h e same l e v g l a s t h e l c w e ~ f l a t , These

r l d g e s and k a o l l s l i e between t h e f l a t and t h e d e l t a t o t h o w e s t . The r i d g e 8 have a g e n e r a l e a s t - t o - w e s t o r i e n t a t i o n . The solathern r i d g e e x t e n d s t o t h e d e l t a between Boot. Lake and Twin Lake,, The c e n t r e r i d g e e x t e n d s t o t h e s o u t h end of t k e :?orth h a l f of Twin Lake. The exposed bank o f s o i l h e r e g i v e s a c r o s s - s e c t i o n of t h e r i d g e , The n o ~ t h e s q ~ i d g e e x t e n d s t o t h e n o r t h end of t h e n o r t h h a l f of Twin Lake whose c r o s s - s e c t l o n i s r e v e a l e d i n t h e exposed banks of s o i l h e s e . These ~ l d g e s

and k n o l i s a r e s e p a r a t e d by s w a l e s , t h e most prominent of which i s t h e d e p r e s s i o n e x t e n d i n g s o u t h e a s t from Twin Lake. These

r l d g e s a r e ~ o t c o n t i n u o u s w i t h t h e lower f l a t but a r e i n t e r r u p t e d by sbal33w swales and d e p r e s s i o n s .

The upper level. t o t h e n o r t h e a s t i . s approximately 40 feet above t h e lower f l a t . It i s n o t f l a t and l e v e l n o r a s c l e a r l y d e f i x d b u t c o n s i s t s of t h r e e p a r a l l e l . subdued and rounded

~ n d u . l a t i a n s e x t e n d i n g from t h e s o u t h e a s t t o t h e n o r t h w e s t . There i s a c o n t i n u a l d r o p i n e l e v a t i o n t O t h e northwest where t h e s e

u n d u l a t i o n s merge w i t h t h e Northern F l a t s n o r t h of Twln Lake. Between t h e undu2ations a r e wide shallow s w a 1 . e ~ appsoxlrnately

20 f e e t deep. To t h e n o r t h of Hidden Lake and. b o r d e r i n g the ?as% edge of t h i s second upper l e v e l a r e s e v e r a l p-oml,ner_t k-rlolls

approximately

50

f e e t above t h e g e n e r a l l e v e l w l t h side s l o p e s of 30 d e g r e e s . E a s t of t h e lo we^ f l a t t h e s i d e of Boot Gulley r i s e s c o n t i n u o u s l y f o r 100 f e e t t o t h e second eleva2ed leve:.

5.2 Drainage

The main f e a t u r e i s t h e l s c k of w e l l - d e f i n e d stream c o u r s e s . During t h e s p r i n g t:gcuk I* m e l t w a t e r i s c a r r i e d In

r i v u l e t s which flow through t h e marly s l a a l 2 9 w swales down t o t3?.e

d e l t a . The most prominent s t r e a m f l o w s I n t o t h e s o u t h ha:? of Twin Lake through t h e depressiora b e t w e ~ n the s ~ u t h agd c e n t r a l r i d g e s e x t e n d i n g from t h e lower e l e v a t e d f l a t ,

N o r t h e a s t of 'Twin Lake i n t h e shallow swalea bezweer, t h e low u n d u l a t i o n on t h e upper f l a t s t F ~ e - 2 ape polygoEal f i s s u r e s a ~ r r o x i m a t e l y 1$ f e e t wide and 2 f e e t deep. Dusing

s p r i n & bl?l-:.~i;,.:.-~ Lhese a r e f l . l l e d w i t h wa.te? .tlcwing downsispe t o t h e nortk.west. On t h e lower f l a t , , s p r l n g me?t,water s t 2 y s t.h?

s c a t t e ~ e d polvgonal c r a c k s and I n t,he depress'ons between t.he

h ~ m o c k s urt.21 semcved by s u r f a c e e v a p o r a t i . ? n , A srn.al-2. stagnant. l a k e a p p r s x i m a t e l y 200 f e e t i n d.i.ameter a t t h e e a s t end 0% t h e

Hidden Lake, between t h e e a s t boundary of t h 3 s e c o r d

l e v e l and t h e E a s t e r n Upland, has a small catchment basin ar.d does n o t a p p e a r t o have any o u t l e t .

5.3

V e g e t a t i o n

Or! t h e lower e l e v a t e d f l a t and k ~ o l l s and r i d g e s t~ t h e west between t h e f l a t and t h e E a s t Channel., t h e t r e e s a s e

mixed spruce and b i r c h i n open s t a n d s , The s p r u c e r e a c h a

maximum dlarneter of

9

i n c h e s a t b r e a s t - h e i g h t . The b l r c h , with

a v e r a g e t - w k d i a m e t e r s of 6 i n c h e s , r e a c h a maximum height o f

30 f e e t . There a r e s e v e r a l c h a r r e d s t l m p s i n d i c a t i v e ~ f " C ~ m e y burns. I n t e r s p e r s e d w i t h t h e s p r u c e and b i r c h a s e s 2 a t t e ~ e d willow and a l d e r . The ground cover c o n s i s t s of r e d and gseen

s2hagnum moss, Labrador t e a , b e r r y p l a n t s and i s o l a t e d p a t c h e s of r e i n d e e r moss and g r a s s t u s s o c k s . Hummocks up t o 1 f o o t h i g b occur i n s c a t t e r e d a r e a s . There i s sedge and g r a s s growLng F ~ o m

t h e b o t t ~ m o f t h e s t a g n a n t l a k e on t h e lower f l a t .

Willow t h i c k e t up t o 12 f e e t h i g h grows on t h e lower p a r t of t h e s l o p e from Boot Lake. F u r t h e r up t h e s l o p e t h e r e i s mixed s p r u c e and b i r c h which i s c o n t i n u o u s w i t h t h e t s e e v e g e t a t i o n on t h e f l a t . The g r a v e l l y banks on Twin Lake a t t h e west end of t h e r i d g e s e x t e n d i n g f ~ o n t h e lower f l a t s u p p o ~ t gr?wt,h of s c a t t e r e d willow t h i c k e t and a few b i r c h t r e e s . T k s e i s a d e m e willow t h i c k e t approximately 10 f e e t h i g h i n t h e

d e p r e s s i o n e x t e n d i n g s o u t h e a s t from t h e s o u t h h a l f of Twin Lake, T h i s willow growth e x t e n d s n o r t h a l o n g t h e e a s t s h o r e of t h e

l a k e where t h e r e i s a s m a l l s t a n d o r s p r u c e 60 f e e t h i g h .

On t h e second e l e v a t e d l e v e l , t h e vegetation mixed

s p r u c e and b i r c h up t o 30 f e e t h i g h w i t h

5

t o 10 f e e t b e t w ~ e r , i n d i v i d u a l t r e e s , and willow and a l d e r , and grourld b i r c h

undergrowth. The ground i s hummocky w i t h a v e g e t a t i v e e w e r + 0%

g r e e n sphagnum and r e i n d e e r moss, Labrador t ? a arAd b e r ~ y p l a n t s , There a s e c h a r r e d stumps and s t i c k s i n d i c a t i r i g a f o m e r bu,-!~-,.

I n t h e polygonal c r a c k s i n t h e shallow swales a t t,he

northwest end of t h e second l e v e l t h e r e a r e l i n e s of w l l l ~ w t h i c k e t . The r a i s e d c e n t r e s of t h e a r e a s e n c l o s e d by t h e s e c r a c k s a r e devoid of t r e e growth. Toward +he rlo~';hwest tk?? i n d i v i d u a l polygonal a r e a s become l a r g ? r and t h ? c e n t r e s more hummocky.

Spruce w i t h some b i r c h and s c a t f 2 2 e d clumps of willow and a l d e r t h i c k e t grow on t h e t o p s of t h e h2gh p ~ o m i n e n t k n o l l s ~ o r t h w e s t of Hidden Lake. On t h e s l o p e s b i r c h p~.?dornfnat.es w t t t r

some s p r u c e up t o 40 f e e t h i g h .

The t r e e v e g e t a t i o n of t h e No-th C e n t r a l E1,evsted F l a t s can be d e s c r i b e d under f o u r d i v i s i o n s . Mixed conifelslous-deciduous. a s s o c i a t i o r - of' spruce and b i r c h w 1 t . h s c a t ' t e ~ e d w l . l . 3 . ~ ~ and a l d . e r

t h i . c k e t grows OP. t h e e l e v a t e d l e v e l s . Ths t r e e s on t h e sle:qea ase

mostly b i r c h w i t h s c a t t e r e d s p r u c e , wj.llow, and a l d e r . Sturltsd s p r u c e predominates on t h e lower more pocrs1.y drained. a r e e s w i t h s c a t t e r e d b i r c h , willow, and a l d e r . Dense willow and a l d e r thl.clset

5 . 4 S o i l s and P e r m a f r o s t

The f i r s t e x p l o r a t i o n work on t h e E a s t Three s i t e was c e n t r e d i n t h i s a r e a . When t h e two b o r e h o l e s ( A R 26 and AB 2 7 )

a s w e l l as t e s t p i t AX 8 d i s c l o s e d t h e e x i s t e n c e of g r a v e l l y m a t e , ~ l a l s ; f u r t h e r t e s t p i t s were e x c a v a t e d i n t h e a r e a t o o b t a i n a d d i t i o n a l . f n f o r m a t i o n on the d i s t r l . b u t S o n of t h e g r a n u l a r d e p c s F t s . ExaninatSon o f s o i l t e s t i n g r e s u l t s , f i e i d n o t e s and l c c a t i o n of t.hs t e s t p i t . % s u g g e s t s t h a t s i m i l a r s o i l c o n d i t i o n s o c c u r f n t h r e e aubdlv3.s.9~?.:3 of t h e a r e a : f . a, l.-me: i l a t

-

p o t e n t i a l t o w n s i t 2 a r e a . ( b ; upper f l s t

-

p o t e n t i a l a i r s t r i p a r e a #1 ( c ) rTdges and s w a l e s . (a) L m e F F l a t

Bor3bole AB 26 and t e s t p i t s AX 10, 11, and 23 were locat.ed on t:he lower f l a t which is t h e a r e a j u s t n o r t h of Boot Lake. A we73.-graded sandy g r a v e l was covored by v a ~ y i n g d e p t h s of' d e c o m p ~ s e d and undecom c s e d organ1.c ma.teria1

(4

i n c h e s in AX 11 t.o 13 f e e t ir. AX 237. The d e p t h t o f r o z e n ground ranged

f ~ o m 5 i.;l.?hea t o 28 i n c h e s below t h e ground s u r f a c e ( ~ u g i ~ s t 1, 1 9 5 4 ) . The g r a v e l was p r ~ d o m i n a n t l y w e l l bonded by i c e a l t h o u g h nc: i c e

w a s di_sce.rnible. I c e segregation i n t h e o r g a n i c and s i l t y c o v e r m a t e r l a l ~ s n g o d from i r r e g u 1 a r l . y o r i e n t e d i e r i s e s , h a i r l i n e t o

4

i n c h t%.i.ck ( A X 1 0 ) t o i r r e g u l a r l y or'le.n+;ed n a s s i v e i c e 8 i n c h e s t h i c k (AX 23), No samples were t a k e n f-om t h e g r a v e l f o r m o i s t u r e

( i c e ) c o n t e n t d e t e m i n a t l . o n s b u t s e v e r a l were t a k e n f ~ o m t h e o v e r l y l . n g n?.aterlal

.

Mois5ure c o n t e n t s ( b y weigh.t.) ranged f r o m

60 p e r ?.era? i:Sn t h e san.dy e.i!!t) t o 1.,5(2C per sent.* (in t h e decoxr.posn.3 o r g a r ~ l . ~ ma-~e-!.al :I ,

( b )

-

3 p p e r P l a t

S w e x a l p i t s ( A X 1 2 , 13,

14,

aad 31.) were dug or2 t h ?

l o ~ g rY.c-gew ( u p p e r l e v e l ) on t h e n o r t h e s s t s i d e a? t h i s H o r t h C e n t r a l E l e v a t e d F l a t s r e g i o n . The sell was f r c z e n i ~ 9 X e d f a t e l y

below t h e l l v e a o s s c o v e r of

4

i n c h e s to 1.2 i,ri.ches ( ~ u g u s t 2 5 , 1 9 5 4 ) . Random s t o r ~ e s up t o 1 i n c h i~ d i a m e t e ? weye s . c a t t e r e c ! through3ut

the greyl.sEz brown s i l t y c l a y matezaial. R o , r i t n , t w i g s arid s t r e a k s of b l a c k o s g a n i c m a t e r i a l were e v i d e n t t h r o u g h o u t t h e d s p t k of t h e p i t . Jse s e g ~ e g a t . i o n in a 1 1 h o l e s r w g e d from m a t e r i a l v~el.1 bonded by :Lee ( i c e n o t d i s c e r n i b l e by e y e ) t o 2 s r e g u l a r l . y c r i ~ n f e d l&-in<:.h t h l . c k i c e l e n s e s . Massive i - e f s o m 1 foot. t.c 1* f e e t ,

t h i c k was fo1m.d a p p r o x i m a t e l y 2$ f e e t below t3he s u r f a c e . Rep-eseK- t a t i v e m o 1 3 t 7 ~ . r e c o ~ t e n t s ranged fr-OP,

40

p e r cc;'~.t $ 0 260 I;er c.en'C

mrlth. ,an a v e r a g e v ~ l . ~ e cf a b m t 95 p e r c ~ n t ; . The h i g h e r m ~ f s t - ~ l r e c o n t e n t c s c u r r e d w i t h i n t h e f i r s t . 2 f e e t a ~ d v a . l ? ~ e s d e c r c a s 2 d

general-lg w l t h d e p t h .

+ Moistux8e conT.ents o r a weigh^ D a s l a 1.2 c r g a r ~ i c m a t e r i a l t e n d

tr=: give e x a g g e ~ a t - e d r e s u l t s becau.je o f t h e rnluch l o w e r speci!;'lr:

grs7it.g of crga?.lc m a t e r i a l . On a vol-d'~!e Sasis t h e mois%ure

c n n t e n t o f t,ke m g a n i c s o i l would be a p p r o x i m a t e l y o n e - h s l f of 1t.s v a l a e on a weight b a s i s .

( c ) Ridges and Swales

The r e l a t i v e l y s h o r t r i d g e which r u n s i n t o t h e c e n t r e of t h e Twin Lake i n a n o r t h w e s t - s o u t h e a s t d i r e c t i o n exposed a g r a v e l l y m a t e r i a l on t h e e a s t bank of t h e l a k e . Samples t a k e n

from two t e s t p i t s on t h i s r i d e ( A X 8 on t h e northwest end exposure and AX 22 on t h e s o u t h e a s t end7 showed t h o m a t e r i a l t o be predorni- n a n t l y a well-graded sandy g r a v e l w i t h an o c c a s i o n a l l a y e r of

b r o w ~ i s h g r e y sandy s i l t 1 f o o t t h i c k , No f r o z e n m a t e r i a l was encourtered i n AX 8 because i t was d r y i n a n a t u r a l exposure. However, f r o z e n ground o c c u r r e d from

8

i n c h e s t o 1 5 i n c h e s below t h e s u r f a c e in AX 22, depending on t h e d e p t h of moss cover

(August 13, 1 9 5 4 ) . I r r e g u l a r l y o r i e n t e d i c e l e n s e s up t o

$

i n c h t h i c k were s c a t t e r e d t h r o u g h t h e f i n e s m z t e r i a l i n t h i s p i t . The c o a r s e r m a t e r i a l ( s t o n e s ) were c o a t e d w i t h i c e up t o 1/16 i n c h Thick. Moisture c o n t e n t s may be e x p e c t e d t o a v e r a g e about 50 p e r c e n t ( b y w e i g h t ) ,,

Although no samples were t a k e n i n b o r e h o l e AB 27 i t proved t h e e x i s t e n c e of g r a v e l l y m a t e r i a l i n t h e r i d g e which e x t e n d s t o t h e E a s t Channel j u s t s o u t h of t h e Twin Lake. Many s t o n e s made d r i l l i n g d i f f i c u l t i n t h i s h o l e snd wash-water

d e p o s i t e d m a t e r i a l appeared t o be a s i l t y w n d . A channel exposure of t h i s r i d g e c o ~ f i r m e d t h e p r e s e n c e cf t h e s e s o i l s .

T e s t p i t AX 21 was e x c a v a t e d Ln a 3wq.le between t h e s e two p r e v i o u s l y d e s c r i b e d r i d g e s . The s o i l was predominantly a g r e y c l a y e y s i l t c o n t a i n i n g many rol-wdec? t o s u b a n g u l a r s t o n e s r a n g i n g i n s i z e up t o 5 i n c h e s iri d i a r n e f e ~ , F r ~ z e n ground was encountered a p p r o x i m a t e l y 12 i n c h e s bslors t h e gnolmd s u r f a c e

( ~ u g u s t 13, 1 9 5 4 ) . Moisture c o n t e n t s ( b y weight; sanged from

35

p e r ce.nt t o

75

p e r c e n t , t h e s o i l cm.t.a-'.;rtl,ng i s r e g ~ l l a r l y o r i e n t e d i c e l e n s e s up t o

$

i n c h t h i c k .

T e s t p i t AX was l o c a t e d on a Low r i d g e between AB 27 and t h e lower f l a t .

Frozen

7

round was b s t w e x

9

m c h e s and

2 3 i n c h e s below t h e s u r f a c e July

25,

1954; The s o i l i n t h i s p i t was predominantly a s i l t y f i n e sand w i t h o c c a s i o n a l s t r e a k s of b l a c k t o brown o r g a n i c m a t e r i a l o Many s t o n e s up t o 6 i n c h e s i n d i a m e t e r l a y immediately below t h e moss cgves which v a r i e d from 4 i n c h e s t o 14 i n c h e s i n d e p t h . Some of t h e s t o n e s were c o a t e d w i t h a t h i n l a y e r of i c e . The s i l t y sand c ~ n t a i n e d h o r i z o n t a l i c e

l e n s e s from h a i r l i n e s i z e t o 1,116 i n c h t h i c k , Massive i c e 1 f o o t t h i c k was encountered a t a d e p t h of 4 f e e t 8 i n c h e s and was coritir,u ous from

6

f e e t

7

i n c h e s t o t h e bottom of t h e p i t a t 8 f e e t

5

i n c h e s . M o i s t u ~ e c o n t e n t s ( b y w e i g h t ) v a r i e d from 30 p e r c e n t t o 85 p e r c e r i t

b u t averaged 55 p e r c e n t .

I n summary t h e lower f l a t and w e s t e s n r i d g e p o r t i o n of t h e North C e n t r a l E l e v a t e d F l a t s a r e grsded g r a n u l a r d e p o s i t s w i t h a v a r y i n g o r g a n i c c o v e r , The upper flat r e g i o n 2s composed

6 .

Topographic D i v i s i o n s

----

-

South C e n t r a l Lowland

----

6 . 1 R e l i e f

T h i s i s a low f l a t a r e a e x t e n d i n g s o u t h e a s t from Boot Lake. A t t h e n o r t h edge of t h i s f l a t i s a group of low rounded k n o l l s r i s i n g 15 t o 2 0 f e e t above the l e v e l of t h e fiat To t h e n o r t h of t h e s e k n o l l s a r e low k n o l l s and s h o r t r i d g e s e x t e n d i n g a l o n g t h e s o u t h e a s t s h o r e of Boot Lake r i s i n g 60 f e e t above t h e l a k e l e v e l and 30 f e e t above t h e l e v e l of t h e f l a t t o t h e s o u t h . T h i s s o u t h c e n t r a l lowland a r e a i s bounded on t h e e z s t b y t h e E a s t e r n Upland.

G e n e r a l l y t h e d r a i n a g e i s t o t h e s o u t h away from Boot Lake. The k n o l l s and r i d g e s a r e w e l l d r a i n e d but t h e low f l a t a r e a between them and t h e two l a k e s a t t h e s o u t h e a s t end a r e p o o r l y d r a i n e d . S p r i n g m e l t w a t e r s t a y s i n t h e i n t e r s t i c e s

of t h e many polygons i n t h i s a r e a because of t h e poor d ~ a i n a g e c o n d i t i o n s .

6

- 3 V e g e t a t i o n

S c a t t e r e d s t u n t e d s p r u c e grows on t h e low f l a t a r e a . The groursd v e g e t a t i o n i s predominantly r e i r ~ d e e r moss w i t h

p a t c h e s of sphagnum moss, Labrador t e a s k)ePFy p l a t s , and g-ass t u s s o c k s . The ground hummocks r e a c h a h e i g h t of 2 f e e t w i t h t h e d e p r e s s i o n s between t h e hummocks v a r y i n g i n w i d t h from a few i n c h e s t o s e v e r a l f e e t .

Dense spruc2 completely c o v s ~ s t h e low rounded h o l i u a t t h e n o r t h end of t h e low f l a t c r e a t i n g a s h a r p c o n t ~ a s t i n

v e g e t a t i o n w i t h t h e s p a r s e t r e e growth on t h e f l a t . B i ~ c h

predominates on t h e s l o p e s of t h e low h i l l s b o r d e r i n g t h e s o t ~ t h s h o r e of Boot Lake, w h i l e mixed s p r u c e a ~ ~ d b i r c h grow on t h e t o p s .

6.4 S o i l s and Permafrost

No e x p l o r a t o r y s o i l i n v e s t i g a t i o n s were c a r r i e d out i ~ , t h e South C e n t r a l Lowland. From an examination of t h e a e r i a l

photographs and s e v e r a l r e c o n n a i s s a n c e t r i p s t h e a r e a s a d j a c e n t t o t h e n o r t h and s o u t h s h o r e s of Boot Lake a p p e a r s i m i l a r . The

low a r e a s s u r r o u n d i n g t h e s m a l l k n o l l s a r e r e l a t i v e l y h i g h e r tha;? t h e d e l t a . Large polygons a r e e v i d e n t i c t h e s e lower a r e a s w i t h f r o z e n ground approximately

15

i n c h e s below t h e i r c e n t r e s

( J U I . ~ 24, 1 9 5 4 ) .

Although t h e a r e a i s low and was a p p r a i s e d i n t h e f i e l d a s u n s u i t a b l e , t h e c h a r a c t e r i s t i c s of t h e s u r r o u n d i n g t e ~ s a l r '

( e . g . , n o r t h of Boot ~ a k e ) s u g g e s t t h a t b e t t e r s o i l c o n d i t i ~ n s may e x i s t . E x p l o r a t o r y work should be c a r r i e d out s i n c e i t s

l o c a t i o n i s important both from t h e p o i n t of view of a c c e s s and p o s s i b l e f u t u r e expansion.

7 . Topographic Di.visions

-

South Central. Rldges

7 . 1

R e l i e f

The South C e n t r a l Ridges a r e a p a r a l l e l s e r i e s of r i d g e s oF v a r y i n g h e i g h t e x t e n d i n g I n a s w ~ t h e a s t - t o - n o r t h w e a t d i r e c t i o n from Long Lake t o t h e d e l t a whZch bounds t h e west s i d e of t h e a r e a . The r i d g e s a r e h i g h e a t and most p r s n o w c e d i n t h p n o r t h where t h i s a r e z b o r d e r s t h e E a s t e r n Upland and SOU$? C e n t r a l Lowland. To t h e s o u t h t h e y become more subdued and i n d i s t i x t i n t h e t r a n s i t i o n zone betwoen t h i s a r e a and t h e

e l o r ~ g a t e d p l a t s and r i d g e s t o t h a e 3 s t

The most prominent r i d g e i s approximately

80

f e e t h i g h e x t e n d i n g from t h e d e l t a a l o n g t h e n o r t h s h o r e of Lake

"B"

toward Long Lake f o r a t o t a l d i s t a n c e of 2 m i l e s , It i s breached by a ~ t ~ e a m f l o w i n g i n t o t h e n o r t h s h o r e of Lake

"B"

and becomes lowca. towasd t h e s a u t h e a s t .

To t h e n o r t h i s a n o t h e r r l d g e approximately t h e same hel.ght. It merges w i t h t h e E a s t e r n Upland a t i t s northwest end but t h e ~ e r n a i g d e r is s e p a r a t e d from t h e uplane by t h e lowlying a r e a extan.ding west from Dumbell Lake.

T o t h e s o u t h and e a s t t h e r e l l e f I s more subdued w i t h low s h o r t r i d g e s and u n d u l a t i o n s which merge w i t h t h e a r e a t o t h e e a s t , The low r i d g e between Lakes

"B"

and

"C"

i s about

40

f e e t h l g h .

7.2 Drainage

There i s d e f i n i t e t o p o g r a p h i c c o n t r s l on t h e s u s f a c s d r a i n a g e pat,t.erri. The s t r e a m s drai;c:.ng 502g Lake, D w b e l l Lake, and t h e two l a k e s a t t h e s o u t h e a s t erid of t h e South C e n t r a l

Lowland, f i ~ w i n p a r a l l e l c o u r s e s bstweeri the ~ i d g e s t o Lake

"B"

and t h e d e l t a . The stseams have c u t tr?r.fibes a b ~ u t

6

f e e t deep and 3.0 f e e t wide.

To t h e s o u t h and e a s t t h e r e ars no d l s t i n c t s t r e a m c o u r s e s and t h e lowlying a r e a s among t h e l.ow s h o r t r i d g e s and u n d u l a t i o n ? a r e p o o r l y d r a i n e d .

V e g e t a t i o n

B i r c h up t o 30 f e e t h l g h pr?dorni:~ate on t h e s o u t h - f a c i n g s l o p e s of t h e h i g h r i d g e s . On th? n o r t h - f a c i n g s l o p e s a r e mixed spruce and b i r c h . The g r o m d cover on both s l o p e s i s Labrador t e a and b e r r y p l a n t s c o v e r i n g subdued hummocks o f

l e s s than 1 f o o t i n h e i g h t . The i m d e r l y l n g s o i l i s exposed i n %he t o p s of some of t h e hummocks r e v e a l i n g p a t c h e s of s m a l l a n g u l a r and rounded sandstone and limes5ore p e b b l e s up t o

Between t h e r i d g e s t h e lowlying ground s u p p o r t s s c a t t e r e d s t u n t e d s p r u c e , grourlu b i r c h , w l ~ l o w and a l d e r , w i t h a gromd

cover of r e i n d e e r and sphagnum moss, Labyador t e a and b e r r y p l a n t s . Dense willow and a l d e r t h i c k e t grow a l o n g t h e banks and i n t h e stream beds.

I n t h e s o u t h p a r t of t h e a r e a whwe t h e r e l i e f i s more subdded, t h e r e i s some b i s c h growigg 3n t h e s o u t h - f a c i n g

s l o p e s . %herwise t h e v e g e t a t i o n i s u?ifarmly s c a t t e r e d s p r u c e , g ~ o u n d b i r c h , willow and a l d e r w i t h a g?wn.d c o v e r of r e i n d e e r and sphag~lxn moss, g r a s s t u s s o c k s , L a b ~ a d ~ ~ r tcta and b e r r y p l a n t s .

7.4 S o i l s and Permafrost

It was thought t h a t t h ? r i d g e s ~ l m n i n g w e s t - t o - s o u t h e a s t i n t h i s a r e a might p r o v i d e a s o u r c e f c - % > a r u e - g ~ a i n e d r n a t e r l a l . Three t e s t p i t s , AX 15, 1 6 , and

17

were 5xcavated on t o p of a h i g h ~ i d g e , i n a low a r e a , and on a low h i l l t o t h e sout,heast of Lake "5"

.

The ground,with a 5 - i n c h l i v e mos3 c o v e r , was thawed t o a d e p t h of from 12 i n c h e s t o 18 inches *;.?uly 30, 1 9 5 4 ) . The e c . x i c o n s i s t e d of a brown s i l t y c l a y w i f h p a t ~ ? ? ~ s of o r g a n i c rnatesial and s t o n e s lclp t o

3

i n c h e s i n diamet.e- rrik?ch d e c r e a s e d i n nimber wf t h d e p t h . Small p o c k e t s of a g r e y , , g ~ - a K u . l a r - l o o k i n g c l a y e y m a t e r i s l oc2ursed randomly throughout t h , ? d e p t h of t h e p i t . The

p a r t i c l e s i3 t h e p o c k e t s were t h i n l y c..=atsd w i t h i c e a l t h o u g h I,ce s e g r e g a t i o n throughout t h e o t h e r sci:. r a ~ g e d fsom m a t e r i a l w e l l bonded with i c e t o s o i l s c o n t a i n i n g s e g u l a - l y and i r r e g u l a r l y o r - i e n t e d i c e l e n s e s from h a i r l i n e t o

3

i r < c h i n t h i c k n e s s .

Moisture c o n t e n t s v a r i e d f ~ o m 22 p e r cen.5 ti] 6 1 p e r c e n t averagi:i.s

39

p e r c e n t ( 5 y w e i g h t ) . I n most 7asm3s t h e m o i s t u r e l ? o n t e n t s exceeded t h e l i q u i d l i m i t v a l u e s of the s ~ I 1 .

The above d e s c r i p t i - ? n applLi?3 % c t h e a r e a e a s t of Lake "9"

and n o r t h of Long Lake. No infomatlo:- I s available on t h e a r e a t o t h e soufh a3d west of t h e two la!~ss.

8.

Topographic D i v i s i o n s

-

Long Lake P l a t s and Ridges 8.1 R e l i e f

The t o p o g r a p h i c f e a t u ~ e s i c t.he Long Lake f l a t s and r i d g e s a r e a l i g n e d i n a n e a s t - w e s t d i ~ e c t 2 o ~ . The d e p r e s s i o n c o n t a i n i n g Long Lake i s p a r a l l e l t o and c o n t s o l l e d by t h i s

a l i g n m e n t . T h i s d i v i s i o n .is t h e soix+h end of t h e E a s t Three ~ i t e a r e a and i s bounded on t h e 3ou%h by th,? Mazkenzie D e l t a . To t h e west l i e t h e low r i d g e s and lmdulati2i-:s of t h e South Central. r i d g e s . To t h e n o r t h and e a s t 5 ' l l a t s and r l . d g e s of t h l s s o u t h e r n a r e a merge i n t o t h e Easteat-~. iJpla::!.d.

That s e c t i o n of t h e d i v i s i o n l y i n g s o u t h of Long Lake r i s e s from t h e d e l t a i n a s e r i e s of naysow e h n g a t e d f l a t s and r i d g e s o r i e n t e d i n an e a s t - t o - w e s t d i . r e c t i o n . The h i g h e s t r i d g e i s a b o u t . 3 0 0 y a r d s s o u t h of Long Lake a2d approximately l , O O f e e t above t h e d e l t a . From h e r e , t h e r e I s a s t e a d y drop of

8~

f e e t to t h e s h o r s of Long Lake. T h i s ~ l d g e i s h l g h r s t a t t h e e s s t

riear t h z Eastern Upland and becomes lower azzd more subdued t c t h e west. Opposite t h e s o u t h sho-?e of' Lor'g Lake i t i s 30 f e e t

high afid

60

t o 130 f e e t wide. It s e p a r a t e s two e l o n g a t e d narrow f l a t s e a c h 1 m i l e long and 200 t o 300 y a r d s wide.

Y:r.3m t h e 2nd of Long Lake t h e m 1s a low a r e a e x t e n d i ~ g

1 _{m i l ? t.:? f h s e a s t . It i s bo!.~.ded on t , h e ,?as% by an e a s t w e s t}

:;t?f,2g%

l5Q

f 3 2 t hXgh which e x t e n d s t o tSh4 Eas'yern Upland. N o ~ t h of L:ng Lake i s a s e r i e s of s l o p e s , f 13% and low r i d g e s ~ l s l n g

c o ~ t i c ~ a L l y t o t h e Eastesr, Upla?d t o t.ht7 no:<th and merging i n t . 0

+9e South C e n t ~ a l Ridge. The wideat 3:::d m3st .;ontSnuous f l.af 1,s t h ? f lrat one n z t h of Long Lake at f3;e t c p of a g e n t l e s l o p e approximately 25 f e e t above t h e l a k e , Th'.? &-\:.?rage width SF t h e f l a t I s

$

m i l e and e x t e n d s from opposi?? t h e middle of Long Lske

t o t h e east f s r I-$ m i l e s .

The Long Lake catzhment b a s x i n c l u d e s a l l t h e r i d g e and f l a t ar?a except

for

some p a r t s soufh of Lmg Lake. Long Lake d r a i n s t b r o l ~ g h a stl.eam f l o w f ~ g t.h-ough t h e South C e n t r a l ~ i d g e s to Lake "B"

.

Spruce up t o 20 f e e t h.?-gh and avesaging 1 0 r e e t a p z r t w i t h s c a t t e s e d b i r c h and alas,- cover t!?.e f ' l r s t s l o p e r . i s i n g f-on +,he d e i k a at t h e soixth end of t h e a-ea,, The g:?amd cover i s pr.edominaaS1y s e l n d e e r moss which i s d ~ y ar,d s p r i n g y . The d e p t h

t o f r o z e n g r o u n d a v e r a g e s 1 5 au:d follows t h e c o n t o w s 13.i

the hummocks (July 24,

1954).

T5ere i s a s h o r t draw 1eadir.g weat and t h e n s o u t h i.nto a s m a l l lak2 a t t h e s o u t h edge of +-he a r e a . Open s t a n d s of

s t u n t e d s p r u c e up t o 20 f e e t h i g h c o v e r t,he n o r t h - f a c i n g s l o p e . ,The ground i s hummocky and covered w i t h . a s i n d e e r moss. On t h e

s o u t h - f a c i n g s l o p e is a dense s t a n d o-i' sp:T7.r2e up t o 45 f e e t 9,tgh.

The average t r u n k d i a m e t e r a t b s e a s t - h e i g h . t i s 9 i n c h e s . The ground hummocks a r e v e r y subdued and have a c o v e r i n g of Labsadas

t e a 9 bekry p l a n t s , and g s a s s .

01:. t h e two long and naysow e ! _ ~ ? . g a t e d f l a t s s o u t h of Long Lake theye I s s c a t t e r e d s t u n t e d sprl.lce up t o

15

f e e t h i g h .

The g r o m d cover i s predominantly reir.d.ee:? moss forming a s p c r ~ ~ y l a y e r . The d e p t h tc; f r o z e n ground !.s

15

lnches [ ~ u l y 2 4 ,

~954).

The v e g e t a t i o n o? t h e r i d g e between t h e two f l a t s

i~ 2redomlnantly s p r u c e up $ 3

25

f e e t h i g h with s c a t t e r e d

b i r c h and a l d e r . The ground hummocks a r e

3

f e e t h i g h and 4 f e e t i n d i a m e t e r covered w i t h apongy r e i n d e e r moss, The moss

averages 8 i n c h e s i n d e p t h below which a r e approximately 7

i n c h e s of thawed o r g a n i c m a t e r i a l ( ~ u l y 1 4 , 1 9 5 4 ) . T h e f r o s t t a b l e f o l l o w s t h e c o n t o u r s of t h e hummock6. To t h e e a s t where t h e ~ i d g e becomes h i g h e r t h e r e a r e o c c a s i o n a l pure s t a n d s of b i r c h i n t e r s p e r s e d w i t h t h e mixed s t a n d s of s p r u c e and b i r c h .

On t h e s l o p e r i s i n g from t h s sou-th s h o r e of Long Lake a-e mixed s p r u c e and b i r c h up t o E 5 'eet h i g h . The ground

hummock^ ai?e covered w i t h r e i n d e e r m a s s a v e r a g i n g 12 i n c h e s i n d e p t h , , Beneath t h e moss a r e a fsw i n c h e s of wet unfrozen

brownish g r e y c l a y e y s i l t w i t h f i n e sand and a n g u l a r and rounded s t o n e 3 up 5 3

6

i n c h e s i n d i a m e t e r .

On t h e s l o p e s n o r t h of Long Lake a r e mixed s t a n d s of s p r u c e and b i r c h up t o 1 5 f e e t h i g h wizh heavy ground b i r c h , willow and a l d e r . Ground hummocks up t o 1 f o o t h i g h have a

c o v e r i n g of sphagnum and r e i n d e e r moss, Labrador t e a and b e r r y plan+,s. To t h e e a s t on t h e most prominent f l a t n o r t h of Long Lake t h e become more s p a r s e and t h z r e i n d e e r moss mcse c o n t i n u o u s . To t h e n o r t h and upslope i n t o t h e E a s t e r n Upland, t h e b i r c h become more dense.

8.4 Sof l a and Permafrost

A f i e l d a p p r a i s a l of t h e Long Lake f l a t s and r i d g e s showed promise f o r a p o t e n t i a l a i r s t r i p on a l o n g f l a t a r e a j u s t n o r t h of Long Lake. S e v e r a l t e s t p i t s (AX 1 9 , 20, 24, 25, 26,

z7

and 28) were excavated on and a d j a c e n t t o t h i s f l a t t e r a r e a , Three o t h e r t e s t p i t s were a l s o ?xcavated i n t h e v i c i n i t y

(AX 18, 29, 391,

Tea5 p i t s AX

19,

20, and 27 l o c a t e d n e a r t h e c e n t r e of t h e f l a t a r e a n o r t h of Long Lake wers $hawed t o an a v e r a g e d e p t h of 12 i n c h e s (August 9 t o 23, 1954) and were covered by

3

i n c h e s oP l i v i n g o r g a n i c m a t e r i a l . The f i r s t 2 t o 4 f e e t of t h e s o i l p r o f i l e c o n s i s t e d of a y e l l a w i s h s i l t c l a y w i t h random s t o n e a up t o 3 i n c h e s i n d i a m e t e r . S t ~ e a k s of b l a c k o r g a n i c m a t e r i a l , t w i g s , and r o o t s were s c a t t e r e d t.hrough t h i s d e p t h .

I c e s e g r e g a t i o n ranged from v e r y f i n s t o 1 - i n c h t h i c k r e g u l a r l y and i r r e g u l a r l y o r i e n t e d l e n s e s . Moisture c o n t e n t s r a n from 30 p e r c e n t t o 166 p e r c e n t , a v e r a g i n g 106 p e r c e n t (by w e i g h t ) ,

A s i l t y g r a v e l l y sand w i t h p a t c h e s of b l a c k o r g a n i c

m a t e r i a l , t w i g s , and r o o t s m d e r l i e s the yellow s i l t c l a y . S t o n e s ranged from 1 i a z h t o

8

i n c h e s i n d i a m e t e r but averaged about

2 i n c h e s I n d i a m e t e r . Some of t h e m a t e s k a l was w e l l bonded w i t h i c e , t h e ~ e r n a i n d e r c o n t a i n i n g i r ~ e g u l a ~ l y o r i 2 n t e d I c e l e n s e s up t o 318 l n c h t h i c k . Moisture c o n t e n t d e t e r m i n a t i o n s ranged from 20 per c e n t t o 95 p e r c e n t and averaged approximately 45 p e r c e n t ( b y w e i g h t ) .