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Geologic Unit: Torok
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Map showing publication footprint
  • Usage in publication:
    • Torok formation*
  • Modifications:
    • Named
    • Biostratigraphic dating
  • Dominant lithology:
    • Silt
    • Shale
    • Conglomerate
    • Graywacke
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Gryc, George, Patton, W.W., Jr., and Payne, T.G., 1951, Present Cretaceous stratigraphic nomenclature of northern Alaska: Washington Academy of Sciences Journal, v. 41, no. 5, p. 159-167.


Summary:

Type locality designated as Torok Creek, tributary to Chandler River in vicinity of Castle Mountain, Southern Foothills [at about 68 deg 34'N, 152 deg 35"W, Chandler Lake quad] northern AK. Well exposed on Chandler and Kiruktagik Rivers in vicinity of Tuktu Bluff about 11 mi north of Castle Mountain. Also widely exposed in east-west belt in Southern Foothills. Comprises 2000 ft of dark silt and clay shale with limestone concretions in lower part and about 8500 ft of dark shale and marine conglomerate and graywacke sandstone in upper part at Castle Mountain. Total thickness at Castle Mountain is 10,500 ft, at Tuktu Bluff, 6000 ft. Unconformably overlies Okpikruak formation (new) at most places. Underlies Nanushuk group; contact believed to be gradational. Contains scarce Aptian and early Albian fauna. Age given as Early Cretaceous.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok formation*
  • Modifications:
    • Revised
    • Biostratigraphic dating
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Patton, W.W., Jr., 1956, New and redefined formations of Early Cretaceous age, IN Gryc, George, and others, Mesozoic sequence in Colville River region, northern Alaska: American Association of Petroleum Geologists Bulletin, v. 40, no. 2, p. 219-223. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Torok formation of Gryc and others (1951) is redefined to exclude coarse clastic facies of sandstone, conglomerate and intercalated shale sequence that overlies Okpikruak formation and crops out along southern margin of Foothills; these beds now named Fortress Mountain formation (new). Type locality of Torok formation designated as Torok Creek and Chandler River between mouth of Torok Creek and mouth of Kiruktagiak River. Type section (approximately 6000 ft thick) is between 68 deg 40'N and 68 deg 43'45"N along Chandler River and Torok Creek. Fossils indicate late Early Cretaceous age.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Robinson, F.M., 1958, Test well Grandstand area, Alaska, with section on micropaleontologic study of Grandstand Test Well 1, northern Alaska, by H.R. Bergquist, IN Exploration of Naval Petroleum Reserve No. 4 and adjacent areas, northern Alaska, 1944-53; Part 5, Subsurface geology and engineering data: U.S. Geological Survey Professional Paper, 305-E, p. E317-E339. [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/pp/pp305E]


Summary:

Upper part of Torok formation recognized in subsurface of Grandstand Test Well 1 (68 deg 57'58"N, 151 deg 55'02"W) on Grandstand anticline, 30 mi south of Umiat, Northern Foothills, northern AK. Top surface of Torok reached at depth of 2650 ft. No appreciable lithologic break found between overlying Tuktu formation and Torok. Foraminifers from Torok identified by H.R. Bergquist are listed in report.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Chapman, R.M., and Sable, E.G., 1960, Geology of the Utukok-Corwin region, northwestern Alaska, IN Exploration of Naval Petroleum Reserve No. 4 and adjacent areas, northern Alaska, 1944-53; Part 3, Areal geology: U.S. Geological Survey Professional Paper, 303-C, p. C48-C167, (incl. geologic map, scale 1:125,000) [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/pp/pp303C]


Summary:

In Utukok-Corwin region unit is exposed in 3- to 12-mile-wide lowland belt that lies along boundary between southern and northern foothills as far west as Ipewik and Kukpuk Rivers. Is about 6458 ft thick. Overlies Fortress Mountain formation and may be in part equivalent to it; underlies Kukpowruk formation with contact gradational and intertonguing. Measured section on Archimedes Ridge anticline, lists of fossils with locations, and geologic map of Utukok-Corwin region included in report.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok Formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Brosge, W.P., and Whittington, C.L., 1966, Geology of the Umiat-Maybe Creek region, Alaska, with section on heavy mineral studies of the Umiat-Maybe Creek region by R.H. Morris, IN Exploration of Naval Petroleum Reserve No. 4 and adjacent areas, northern Alaska, 1944-53; Part 3, Areal geology: U.S. Geological Survey Professional Paper, 303-H, p. H501-H638, (incl. geologic map, scale 1:125,000)


Summary:

Torok Formation of Early Cretaceous (Albian) age recognized in report area [Umiat-Maybe Creek in southeastern part of Naval Petroleum Reserve No.4, Arctic Slope, northern AK] at expense of Oumalik and overlying Topagoruk Formations of Robinson and others (1956).

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok Formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Molenaar, C.M., 1988, Depositional history and seismic stratigraphy of Lower Cretaceous rocks in the National Petroleum Reserve in Alaska and adjacent areas: U.S. Geological Survey Professional Paper, 1399, p. 593-621.


Summary:

Isopach map shows extent of Torok Formation in surface and subsurface of National Petroleum Reserve in Alaska and adjacent areas. Is represented on seismic lines by bottomset (basinal), foreset (slope), and topset (shelf) reflectors described as facies of Torok. Rocks formerly called Oumalik Formation now recognized as Torok. Topagoruk Formation is part of highly-transgressive zone between Torok and Nanushuk Group. Names Oumalik and Topagoruk Formations are here abandoned. Torok Formation overlies pebble shale unit in subsurface; overlies Fortress Mountain Formation in southern foothills. Underlies Nanushuk Group. Age remains Early Cretaceous.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Torok Formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Mull, C.G., Houseknecht, D.W., and Bird, K.J., 2003, Revised Cretaceous and Tertiary stratigraphic nomenclature in the Colville basin, northern Alaska; Version 1.0: U.S. Geological Survey Professional Paper, 1673, 51 p., Prepared in cooperation with Alaska Dept. Nat. Resources, Div. Geol. Geophys. Surveys and Div. Oil and Gas [http://ngmdb.usgs.gov/Prodesc/proddesc_54811.htm]


Summary:

Pg. 5 (fig. 4), 6-8 (Table 1), 9-11. The Torok Formation, as revised by Patton (1956), is used here. Chiefly dark-gray to black silty shale, mudstone, and clay shale with interbedded thin-bedded siltstone and lesser amounts of greenish-gray, thin-bedded siltstone and fine-grained sandstone. Fine- to medium-grained sandstone common in lower part. Southern outcrop belt 18,500+ feet thick, thins to <3,100 feet beneath northern Arctic Coastal Plain. Fossils. Age is Early to early Late Cretaceous (Aptian to Cenomanian); the Torok becomes younger from west to east. Type section stated.
Type section of Patton (1956): approx. 6,000 ft section along Torok Creek and Chandler River [between approx. Lat. 68 deg. 40 min. and 68 deg. 44 min. 30 sec. N., in northwestern Chandler Lake C-4 quadrangle, scale 1:63,360, Alaska-North Slope Borough], northern AK; lower part along Torok Creek, in secs. 2, 3, 4, and 9, T. 9 S., R. 2 W., and continues up-section along Chandler River, in secs. 1 and 2, T. 9 S., R. 2 W., and in secs. 23, 25, and 36, T. 8 S., R. 2 W.

Source: Publication.


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