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CONTENTS

Abstract
Introduction
Stratigraphy
Torok Formation (Unchanged)
Nanushuk Formation (Revised)
Colville Group (Abandoned)
Seabee Formation (Revised)
Tuluvak Formation (Revised)
Schrader Bluff Formation (Revised)
Prince Creek Formation (Revised)
Sagavanirktok Formation (Revised)
Sagwon Member (Revised)
White Hills Member (New)
Franklin Bluffs Member (Revised)
Summary
References Cited

FIGURES

  1. False-color composite Landsat image of northern Alaska showing quadrangles discussed in text and approximate outline of the Colville basin.
  2. False-color composite Landsat image of the Umiat, Sagavanirktok, Chandler Lake, and Philip Smith Mountains quadrangles, northern Alaska, showing township-range grid, streams, and other features mentioned in text and figure captions.
  3. Chronostratigraphic column for the Colville basin, northern Alaska, showing revised stratigraphic nomenclature and ages of units discussed in this paper.
  4. Chart illustrating relationships between former stratigraphic nomenclature and revised stratigraphic nomenclature as proposed in this paper for the Colville basin, northern Alaska.

5-7. Photographs of Torok Formation:

  1. Sandstone in turbidite channel incised into interbedded mudstone and thin turbidite sandstones of Torok Formation on Heather Creek, Killik River quadrangle.
  2. Poorly sorted pebble-cobble conglomerate in debris-flow deposit within Torok Formation, Autumn Creek, Chandler Lake quadrangle.
  3. Relatively incompetent folded and faulted mudstone in Torok Formation, Autumn Creek, Chandler Lake quadrangle.

8-11. Photographs of Nanushuk Formation:

  1. Slope Mountain, a prominent landmark in northwestern Philip Smith Mountains quadrangle near Mile 305 of the Dalton Highway, where upper part of mountain consists of dominantly nonmarine sandstone, conglomerate, and coal of upper Nanushuk Formation overlying dominantly marine sandstone of lower Nanushuk, which prograded over outer shelf silty mudstones of Torok Formation exposed in lowermost slope.
  2. Nanushuk Formation on south flank of Arc Mountain anticline at Nanushuk River, eastern Chandler Lake quadrangle.
  3. Resistant, crossbedded sandstone and conglomerate in characteristic exposure of upper part of Nanushuk Formation west of the Anaktuvuk River, Chandler Lake quadrangle.
  4. Crossbedded sandstone in upper part of lower Nanushuk Formation on Slope Mountain, Philip Smith Mountains quadrangle.

12-14. Photographs of Seabee Formation:

  1. Exposure of Seabee Formation overlain by Tuluvak Formation along Colville River at base of Umiat Mountain, central Umiat quadrangle.
  2. Seabee Formation at base of Umiat Mountain showing predominant mudstone lithology with yellow tuff interbeds.
  3. Bentonitic shale with large concretions in upper part of Seabee Formation, east fork of Tuluga River.

15-20. Photographs of Tuluvak Formation:

  1. Marine or marginal marine sandstone and pea-gravel conglomerate in Tuluvak Formation in May Creek syncline, north of May Creek, eastern Chandler Lake quadrangle.
  2. Discontinuous, resistant ledge of Tuluvak Formation on north flank of Big Bend anticline, south side of Outpost Mountain, southern Umiat quadrangle.
  3. Fluvial conglomerate of Tuluvak Formation near the Anaktuvuk River in the southern Umiat quadrangle.
  4. Crossbedded quartz- and chert-pebble conglomerate and sandstone in Tuluvak Formation at same outcrop shown in figure 17.
  5. Bioturbated marine sandstone in Tuluvak Formation along west side of Nanushuk River on south side of Rooftop Ridge, Chandler Lake quadrangle.
  6. Oil-stained sandstone in Tuluvak Formation, north flank of Big Bend anticline near Outpost Mountain.

21-25. Photographs of Schrader Bluff Formation:

  1. Exposure of upper part of Schrader Bluff Formation at Shivugak Bluff, along Colville River east of Umiat.
  2. Tuff beds intercalated with tuffaceous mudstone and bentonite in upper part of Schrader Bluff Formation at Shivugak Bluff.
  3. Shallow-marine sandstone in upper part of Schrader Bluff Formation at Shivugak Bluff showing lag of marine shells in a hummocky cross-stratified facies.
  4. Upper part of Shivugak Bluff showing section that includes the contact between the Schrader Bluff Formation and the overlying Prince Creek Formation.
  5. Nonmarine channel sandstone incised into shallow-marine sandstones in Schrader Bluff Formation at Shivugak Bluff.

26-30. Photographs of Prince Creek Formation:

  1. Exposures of nearly horizontal Prince Creek Formation forming bluff on west side of the Colville River near confluence with the Anaktuvuk River, Umiat quadrangle.
  2. Exposure of Prince Creek Formation along west side of the Colville River, just north of confluence with the Anaktuvuk River where light-colored, nonmarine sandstones are interbedded with dark-colored coal and carbonaceous mudstone.
  3. Silty mudstone, coal, and sandstone in upper Prince Creek Formation at Sagwon Bluffs, central Sagavanirktok quadrangle.
  4. Conglomerate in Prince Creek Formation along Colville River in northern Umiat quadrangle.
  5. Medium- to coarse-grained, pebbly, crossbedded sandstone in Prince Creek Formation at Shivugak Bluff.

31-36. Photographs of Sagwon Member of Sagavanirktok Formation:

  1. Sandstones and conglomerates of Sagwon Member of Sagavanirktok Formation at VABM Gard on northwest side of Sagwon Bluffs, central Sagavanirktok quadrangle, overlying the Prince Creek Formation in lower slopes.
  2. Poorly consolidated conglomerates at base of Sagwon Member of Sagavanirktok Formation at VABM Gard on west side of Sagavanirktok River.
  3. Lower part of Sagwon Member of Sagavanirktok Formation, at north end of Sagwon Bluffs on east side of the Sagavanirktok River, dipping regionally northward beneath the Arctic Coastal Plain.
  4. Cliff-forming sandstone and conglomerate in lower part of Sagwon Member of Sagavanirktok Formation on east side of the Sagavanirktok River.
  5. Quartz-rich sandstone, with quartz- and chert-pebble lag, overlying coal in Sagwon Member of Sagavanirktok Formation.
  6. Oxidized clinker zone in coal-bearing upper part of Sagwon Member of Sagavanirktok Formation in southeast part of the White Hills.
37-42. Photographs of White Hills Member of Sagavanirktok Formation:
  1. White conglomerate cap of basal White Hills Member of Sagavanirktok Formation, at southwest end of the White Hills, western Sagavanirktok quadrangle.
  2. Outcrop in an unnamed stream drainage on northwest side of the White Hills where poorly consolidated sandstone and conglomerate yield the typical rounded hillsides pattern of the White Hills Member of Sagavanirktok Formation.
  3. Crossbedded fluvial sandstones and conglomerates in basal part of White Hills Member of Sagavanirktok Formation along the Toolik River.
  4. Bluff along east bank of Sagavanirktok River and southern end of Franklin Bluffs, showing contrast between Franklin Bluffs Member of Sagavanirktok Formation and brown-weathering, lignite-bearing silty mudstone of upper part of White Hills Member.
  5. Crossbedded sandstone and conglomerate in basal White Hills Member of Sagavanirktok Formation in an unnamed stream drainage on northwest side of the White Hills.
  6. Poorly consolidated, crossbedded sandstone and conglomerate of the White Hills Member of Sagavanirktok Formation in unnamed stream drainage on northwest side of the White Hills.

43-44. Photographs of Franklin Bluffs Member of Sagavanirktok Formation:

  1. White conglomerate cap and underlying sandstones of Franklin Bluffs Member of Sagavanirktok Formation at south end of Franklin Bluffs, Sagavanirktok quadrangle.
  2. White conglomerate cap and underlying pink-weathering sandstones of Franklin Bluffs Member of Sagavanirktok Formation at Franklin Bluffs.
  1. Wireline log of Mobil West Kadleroshilik Unit #1 well showing correlation of lower Tertiary stratigraphic nomenclature in Franklin Bluffs area with subsurface nomenclature to the northeast.

46-48. Photographs of Franklin Bluffs Member of Sagavanirktok Formation:

  1. Brown-weathering, sandy siltstones in lower part of Franklin Bluffs Member of Sagavanirktok Formation at Franklin Bluffs.
  2. Poorly consolidated, crossbedded fluvial sandstones in Franklin Bluffs Member of Sagavanirktok Formation at Franklin Bluffs.
  3. Pebble lag in crossbedded sandstone in Franklin Bluffs Member of Sagavanirktok Formation at Franklin Buffs.

TABLE

  1. New and revised Cretaceous and Tertiary stratigraphic nomenclature, Colville basin, northern Alaska.

CONVERSION FACTORS

INDEX OF FIGURES


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