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UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY REGIONAL BEDROCK GEOLOGIC MAPS ALONG THE DALTON HIGHWAY, YUKON CROSSING TO TOOLIK, ALASKA Compiled by W. P. ~ros& and W. W. Patton, Jr. Open-F i 1 e Report 82-1071 This report is preliminary and has not been reviewed for con- formity with U.S. Geological Survey editor i a1 standards and stratigraphic nomenclature.

BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

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Page 1: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY

REGIONAL BEDROCK GEOLOGIC MAPS ALONG THE DALTON HIGHWAY,

YUKON CROSSING TO TOOLIK, ALASKA

Compiled by

W. P. ~ r o s & and W. W. Patton, Jr.

Open-F i 1 e Report 82-1071

This report i s preliminary and has not been reviewed for con- formity w i t h U.S. Geological

Survey editor i a1 standards and stratigraphic nomenclature.

Page 2: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

TABLE OF CONTENTS

Page

Introduction ----------------c-q-----1------------------------------ 1

Correlation of map uni ts , Map A .................................... 3

Geologic symbols, Maps A and ..................................... 3

Map symbols, Maps A and & .......................................... 3

Description af map u n i t s , Map A .................................... 4

Sources of map infomation, Map A ................................. 5

Correlation of map units, Map B .................................... 6

Description of map units, Map B 7

Sources of map information, Map B .................................. 9

ILLUSTRATIONS

Figure 1, Index map ............................................... 2

Map A . Yukon Crossing t o Wiseman .............................. Plate 1

Map B. Wiseman t o Tool jk ....................................... P l a t e 1

Page 3: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

INTRODUCTION

The Dalton Highway was originally buff t as a haul road f o r construction o f the trans-Alaska p i p e l i n e , and has now been opened t o the public from L i vengood t o the southern Brooks Range. Reconnaissance geological quadrangle maps at 1:250,000 scale show the bedrock geology o f the region crossed by the highway between Livengood and the Nor th Slope; several o f these maps were published before the highway was b u i l t . In preparation for a highway f i e ld t r i p t o be sponsored by the Fourth International Conference on Permafrost in Fairbanks in 1983, we have s m a r i z e d the geology frm these maps f o r a 50-km wide strip along the highway from the Yukon River to the northern foothills of t he Brooks Range.

The strip map, a t 1:500,000 scale, i s i n two parts (Fig, 1 ) . Map A covers the region from the Yukon crossing t o the town of Wiseman i n the southern Brooks Range. Map 8 covers the region from Wiseman to the northern f o o t h i 11s af the Brooks Range near the abandoned Tool i k construct ion camp. These maps emphasize the regional differences i n character o f the various bedrock terranes crossed by the highway; t he re f ore, some geologic u n i t s r hown on the original maps have been grouped and generalized. An even broader regional overview i s given briefly i n the report by Patton and others (1977) l isted i n the references for Map A. The traveler interested in the details o f the roadside geology will need t o consult the original geologic quadrangle maps listed as sources o f map information as well as the new edit ions o f the topographic quadrangles t h a t show the 1 ocati on o f the highway.

Page 4: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

-- 1 Figure 1 . Index map o f Alaska I

showing l oca t i on of map

areas A and 0 . I

Page 5: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

CORRELATION OF MAP UNITS

Map A Yukon Crossing t o Wiseman

I Metamorphic I Igneous Sedimentary rocks rocks rocks

I Miocene

1 Pa 1 eocene

Upper Cretaceous

Lower Cretaceous

1 QUATERNARY d .

t

TERTIARY

CRETACEOUS

JURASSIC

TRIASSIC

PERMIAN

PENNSYLVANIAN

NISSISSIPPIAN

DEVON I A M

GEOLOGIC SYMBOLS Maps A and R

Contact. Incl udes some faults --- Faul t . Dashed where approximately

1 ocaled. - / = , . . .

Thrust f a u l t . Saw teeth on upper pla te . Dotted where concea 1 ed.

MAP SYMBOLS Maps A and B

Locat ion and name o f town o r cons t ruc t i on camp.

5 Locat ion and number o f pump s t a t i on.

3

Page 6: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

DESCRIPTION OF MAP UNITS

Map A, Yukon crossing t o Wiseman

Sedimentary Rocks

UNDIFFERENTIATED SURF I C I A L DEPOSITS (Quaternary) --Shown only in the 1 argest val I eys.

SEDIMENTARY ROCKS (Miocene?) --Tuff, s i 1 tstone, conglomerate and coal. flonmari ne.

CONGLOMERATE AND SANDSTONE (Upper and Lower Cretaceous)--Clasts o f quartz, quartz i te , schist and Igneous rocks. Nomar i ne.

IGNEOUS PEBBLE CONGLOMERATE (Lower Cretaceous; A 1 b i an)--Cl asts of mafic volcanic rocks, chert and graywacke. Marine(?).

MARINE GRAYWACKE AND MUDSTONE (Lower Cretaceous; A 1 b i an)--Cl asts o f volcanic rocks.

UNDIVIDED GRAYWACKE AND SILTSTONE (Upper and Middle(?) Devoni an)-- Dark gray phyll i t e and polymetamorphosed chl ori t i c wtas i l t s tone , T h i n beds o f marble i n upper part. Undivided u n i t a1 so i ncl udes metagraywacke fa r ther north {Map B) .

UNNAMED CHLORITIC AND CALCAREOUS METASEDIMENTS (Middle(?) Devonian)-- Brown and gray weathering partly calcareous sl ate and phyllite. Polymetamorphosed.

PHYLLITE AND GRAYWACKE (Devonian(?) or younger)--Dark gray phyllite and f ine-grai ned 1 ithic wacke. Sl i ght ly metamorphosed,

U N D I V I D E D CARBONATE ROCKS (Devoni an(?) or younger ) --Marble and cal c- s i l i c a t e hornfels.

Igneous Rocks

VOLCANIC ROCKS (Quaternary or Upper T e r t i ary) - -Fl a t - 1 y i ng f 1 om o f olivine basa l t ,

FELSIC AND INTERMEDIATE VOLCANIC ROCKS Paleocene) --Porphyr 1 t i c f 1 ows, brecci a, conglomerate and t u f f .

GRANITIC ROCKS (Lower Cretaceous) --Porphyri ti c quartz monzani t e ; granodiorite and monzonite.

ULTRAMAFIC ROCKS (Jurassic t o Mississippian)--0phiolitic assemblage o f serpentinized peridotite and dunite t h r u s t over volcanic rocks {TrMv) . Jurassic K/Ar ages may da te thrusting rather than pretol i t h (Patton and others, 1977).

Page 7: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

R Mv VOLCANIC ROCKS ( T r i a s s i c , Permi an, Pennsylvanian, and M i s s i s s i p p i an) --Pi 11 ow basa l t , d i abase and gabbro; che r t and che r t y mudstone; l imestone.

Metamorphic Rocks

D v VOLCANIC ROCKS (Upper and Midd le (? ) Devonian)--Mafic greenschis t .

qms UNDIVIDED QUARTZ-MICA SCHIST (Precambri an ( ? ) , 1 ower Paleozoic ( ? ) , Devonian(?), and M iss i ss i pp ian (? ) ) - -Quar tz -mica sch is t , c h l o r i t e s c h i s t and minor q u a r t z i t e . Lower greenschis t t o almandine-amphibol i te fac ies ; a n d a l u s i t e - c o r d i e r i t e ho rn fe l s near Cretaceous g ran i tes .

csm UNDIVIDED CALCAREOUS SCHIST AND MARBLE (Precambrian(?) t o Devoni an(? ) )--Brown-weathering muscov i te -quar tz -ca lc i te s c h i s t in terbedded w i t h sch is tose marble and quartz-mica sch is t .

SOURCES OF MAP INFORMATION

Map A, Yukon c ross ing t o Wiseman I

Brosge, W. P., and Reiser , H. N., 1964, Geologic map and sec t i on o f t h e Chandal ar quadrangle, Alaska: U.S. Geolog ica l Survey M i s c e l l aneous Geologic I n v e s t i g a t i o n s Map 1-375, sca le 1:250,000.

1971, P r e l i m i n a r y bedrock geolog ic map, Wiseman and eastern Survey Pass quadrangles, A1 aska: U.S. Geolog ica l Survey Open-F i l e Report 71-56, 2 sheets, sca le 1:250,000.

~ r o s ~ ; , W. P., Reiser, H. N., and Yeend, Warren, 1973, Reconnaissance geolog ic map o f t h e Beaver quadrangle, A1 aska: U.S. Geolog ica l Survey Miscel laneous F i e l d Studies Map MF-525, sca le 1:250,000.

Chapman, R. M., Weber, F. R., and Taber, Bond, 1971, P re l im ina ry geolog ic map o f t he Livengood quadrangle, Alaska: U.S. Geolog ica l Survey Open-File Report 71-66, 2 sheets, sca le 1:250,000.

I

Chapman, R. M., Yeend, Warren, Brosge, W. P., and Reiser, H. N., 1982, Reconnaissance geo log ic map o f t h e Tanana quadrangle, A1 aska: U.S. Geolog ica l Survey Open-File Report 82-734, sca le 1:250,000.

Patton, W. W., Jr., and M i l l e r , T. P., 1973, Bedrock geolog ic map o f B e t t l e s and southern p a r t o f Wiseman quadrangles, Alaska: U.S. Geolog ica l Survey Miscel laneous F i e l d Stud ies Map MF-492, sca le 1:250,000.

Patton, W. W., Jr., T a i l l e u r , I. L., ~ r o s ~ ; , W. P., and Lanphere, M. A., 1977, P re l im ina ry r e p o r t on t he o p h i o l i t e s o f nor thern and western Alaska, in Nor th American Oph io l i t es : Oregon S ta te Department o f Geology and Minera l I n d u s t r i e s , B u l l e t i n 95, p. 51-57.

Page 8: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

CORRELATION OF MAP UNITS

Map B Wiseman t o Toolik

r 1 Metamorphic 1 Igneous I Sedimentary 1 I rocks I rocks I rocks I

} QUATERNARY

CRETACEOUS

Cretaceous

JURASSIC

i' """an

I

t Upper o r Middle Devonian

j Middle Devoni an

) TRIASSIC

\ PERMIAN PENNSYLVANIAN

) KISSISSIPPIAN

' DEVONIAN

SILURIAN

ORDOVICIAN

CAFIBR IAN

PRECAMBRIAN ( ? ) I I

Page 9: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

DESCRIPTION OF MAP UNITS

Map B, Wisenan to Toolik

Sedimentary Rocks

UNDIFFERENTIATED SURFICIAL DEPOSITS (QUATERNARY) --S hown only I n the largest valleys.

COLVILLE GROUP (Upper Cretaceous)--Sandstone, shale and tu f f . Mostly nomarine. Exposed thickness about 60 m.

NANUSHUK GROUP AND TOROK FORMATION (Upper and Lower Cretaceous; Cenmani an and A1 b i an)--Nanushuk Group: congl merate, sandstone and shale; fluvial and shallow marine; thickness a t least 600 rn. Underlying Torok Formati on: marine shale and s i 1 tstone; more than 130 m thick,

FORTRESS MOUNTAIN FORMATION Lower Cretaceous; A 1 b i an)--Pol ymi ct conglmcrate, wacke, siltstone and shale. Marine and nomarine. Thickness 1300 rn,

OKPIKRUAK F O R M U I O N (Lower Cretaceous)--Rhythmically-bedded siltstone, graywacke and cangl merate. Marine. More than 600 m th ick .

KONGAKUT FORMATION (Lower Cretaceous) --B 1 ack shale and s i 1 tstone; f l o a t t n g chert pebbles i n l o w e r part. Marine, More t h a n 300 m thick,

KONGAKUT FORMATION AND KINGAK SHALE, UNDIVIDED (Lower Cretaceous and Jurassic)--Black shale and siltstone. Marine. As much as 700 m th ick ,

SHUBLIK FORMATION, OTUK FORMATION, SAOLEROCHIT GROUP, LISBURNE GROUP AND KAYAK SHALE UNOJVIDED ( T r i a s s i c , Perrnjan, and Carboniferous)--Shublik Formati on: black calcareous phosphati c shale and s i 1 tstone and gray limestone; marine; 30 t a 150 rn th ick , Otuk Formation: varicolored chert 1 atera1 ly equivalent t o Shubl ik Formation. Sadlerochit Group: siltstone, shale, sandstone and limestone; marine in this area; about 500 m thick. Lisburne Group: gray cherty l imestone and do1 omite; marine; about TOO t o 1000 rn thick. Kayak Shale: black shale, 1 irnestone and sandstone; marine; about 300 rn thick.

L 1 SBURHE GROUP, KAYAK SHALE AND KEKI KTUK CONGLOMERATE UMDIV I DED (Pennsylvanian and Mississippian)--Pennsylvanian part o f Lirburne Group i s t h i n t o absent in t h i s area. Kekiktuk Conglomerate: quartzite and granule conglomerate about 10 m thick present only i n southernmost outcrops, where it under1 i es Kayak Shale and rests unconformabl y on Lower Paleozoic racks.

Page 10: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

Dk KANAYUT CONGLOMERATE (Mississippi an ( ? ) and Upper Devoni an)--Quartz1 te , sandstone, conglomerate and gray to red shale and s i l tstone. F l u v i a1 ; deposited by southwestward flowing streams. About 1000 m thick; absent where Keki k t u k Congl merate rests on Lower Paleozoic rocks.

Oh NOATAK SANDSTONE, HUNT FORK SHALE AND BEAUCOUP FORMATION UNDIVIDED (Upper Oevoni an)--Mostly dark gray shale and s i l tstone; interbedded wacke jn upper par t ; some reef a1 1 imestone and conglomerate i n 1 ower part ; mi nor sandstone throughout. Marine. Upper part consists of prodel t a i c and shore1 i ne deposits gradational i n t o Kanayut Conglomerate. About 1500 to 200Q m t h i c k ; absent where Keki ktuk Congl merate rests on Lower Pal eozaic rocks. Metamorphosed t o s 1 ate and phyl 1 i t e i n southern part o f area.

Dg UNDIVlDED GRAYWACKE AND SILTSTONE (Upper and Middle I?) Devoni an )--Dark gray and gray-green slate and phyllite, meta-graywacke with m a f i c rock cl asts , and chlori t i c meta-si ltstone; t h in f o s s i 1 iferous Upper Devoni an 1 imcstones i n upper part. Pol ymetamorphosed.

Dc UNNAMED CHLOR ITIC AND CALCAREOUS METASEDIMENTS (Middle(?) Devonian) -- Green, red, purple and dark gray slate and phyll i t e ; brown and orange weatheri ng calcareous sl ate, met asandstone and rchi st; gray marble. P o l ymetamorphosed.

Pa UNNAMED VOLCANIC CONGLOMERATE {Devonian(?))--Sheared rnafic pebble conglomerate and breccia grades i n t o volcanic phyllite,

DSs SKAJIT LIMESTONE (Middle Devoni an and S i l uri an)--Gray, non-cherty marble, and gray and orange dolomite. As much as 600 m thick.

Pzcs UNNAMED CALCAREOUS METASILTSTONE (Lower Paleozoic)--Gray and gray-green partly calcareous sl ate and metas i 1 tstone, and gray t h i n-bedded mfcaceous l imestone. Weathers brown and orange.

06v UNNAMED VOLCANIC AND SEDIMENTARY ROCKS (Ordovic i an and Cambri an (? ) )-- Andesit i c and basal t i c pyroclastic rocks and volcanic conglomerate; black and green phyl l ite; s i l l s and dikes of gabbro and d ior i te .

6b UNNAMED B U C K METASILTSTONE (Cambri an)--&l ack, pyritic metasil tstone and phyl 1 i te; t h i n f ossi l i f eraus 1 lmestone 1 ocal 1 y i n upper part. Includes many small unmapped mafjc s i l l s and dikes.

Igneous Rocks

Dv UNNAMED VOLCANIC ROCKS (Upper and Middle( ?) Devoni an) --Gabbro and d i abase s i l l s as much as 100 m thick; pillow basalt flows 10-80 rn thick. Metamorphosed to greenstone and greenschist.

Pzg GRANITIC ROCKS (Devonian(?) and/or Ordovician(?))--Gneissic granodiorite and quartz monzonite with conflicting Ordovician, Devonian and Cretaceous i s o t o p i c ages.

Page 11: BEDROCK GEOLOGIC THE HIGHWAY, CROSSING TOINTRODUCTION The Dalton Highway was originally buff t as a haul road for construction of the trans-Alaska pipeline, and has now been opened

-.

Metamorphic Rocks

qms UNDIVIDED QUARTZ-MICA SCHIST (Precambri an ( ? ) , Devonian(?) and Mississippi an(?) )--Gray t o black, coarse t o fine-grained quartr- muscovite-chlorite-albjte schist , locally with b i o t i t e and garnet. f ncludes some maf i c greenschi s t . Polynetamorphosed. Ages are from D i l Ion, Hamj l ton, and Lueck (1981) and Nelson and Grybeck (1980).

csm UNDIVIDED CALCAREOUS SCHIST AND MARBLE (Precambri an( ?) to Oevanf an(?) ) -- Brown weatheri ng muscori te-quartz-ca1 ci t e sch is t interbedded w i t h schi stose marble and quartz-mi ca s c h i s t . Polynetamorphosed. A 1 tered to calc-silicate hornfels around granitjc rocks Pzg.

SOURCES OF MAP INFORMATION

Map 8, Wiseman t o Toolik

5rosg6, W. P . , Reiser, H. N., Dutro, J. T., Jr., and Detteman. R . L., 1979, Bedrock geologic map o f the Philip Smith Mountains quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-8798, 2 sheets, scale 1:250,000. I

Brosge, W. P., and Reiser, H. N., 1964, Geologic map and sect ion o f the Chandal ar quadrangle, A 1 aska: U ,S. Geologl cal Survey M i scel I aneous Geologic Invest iga t ions Map 1-375, scale 1:250,000.

~roscjh, U. P. , and Reiser, H. N., 1971, Prel i m l nary bedrock geologic map, Wiseman and eastern Survey Pass quadrangles, Alaska: U. S, Geological Survey Open-F i l e Report 71-56, 2 sheets, scale 1:256,000.

6rosgk, W. P., Reiser, H. N., Dutro , J. T., Jr., and Nilsen, T. H., 1979, Geologic map of Devonian rocks In parts of the Chandler Lake and Killik R i v e r quadrangles, Alaska: U.S. Gealogical Survey Open-File Report 79- 1224, scale 1:200,000.

D l 1 Ion, J. T., Hamll ton, W. $., and Lueck, Larry, 1981, Geologic map of the Wiseman A-3 quadrangle, Alaska: Alaska D l v i s i o n of Geological and Geophysj cal Surveys Open-Fi 1 e Report 119, seal e 1:63,360.

Nelson, S. W , , and GryGeck, Oonald, 1980, Geologic map o f the Survey Pass quadrangle, 8rooks Range, A ? aska: U. S. Geal ogical Survey Miscel 1 aneous F i e l d S t u d i e s Map MF-1176-A, 2 sheets, scale 1:250,600.