Age and correlation of the Otuk formation, North-Central Brooks Range, Alaska
Conference
·
· Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:6197325
Allochthonous Triassic rocks of the north-central Brooks Range thrust belt were originally mapped as part of the Middle to Upper Triassic Shublik Formation. Recently, these strata were named the Otuk Formation. Detailed paleontologic studies of 11 measured sections more precisely document the age of the Otuk and show that its base is older than the base of the Shublik and that its top is younger than the top of the Shublik. Megafossils (pelecypods and ammonites) and microfossils (radiolaria, conodonts, and foraminifers) indicate an age range of Early Triassic (Dienerian-Smithian or older) to Middle Jurassic (Bajocian). The lithology consists of 120 m (390 ft) of interbedded, very fine-grained rocks (shale, limestone, and chert) representative of very slow deposition, below wave base in an open marine environment. The Otuk formation does not contain suitable reservoir rocks, but organic geochemical data indicate that the shales are possible oil source rocks. The Otuk formation is disconformable with both the underlying Permian (Wolfcampian-Guadalupian) Siksikpuk Formation and overlying Lower Cretaceous (Valanginian) coquinoid limestone and shale. These unconformities are correlative with similar unconformities in the northeastern Brooks Range and subsurface of the North Slope. Thus, the Otuk formation is a condensed, deeper water, more distal equivalent of the Ivishak and Shublik Formations, Karen Creek Sandstone, and lower Kingak Shale of the northeastern Brooks Range and equivalent subsurface units of the North Slope.
- Research Organization:
- Sohio Petroleum Co., Houston, TX
- OSTI ID:
- 6197325
- Report Number(s):
- CONF-8505215-
- Conference Information:
- Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 69:4
- Country of Publication:
- United States
- Language:
- English
Similar Records
Facies correlation and basin analysis of Ivishak Formation, Arctic National Wildlife Refuge (ANWR), Alaska
Stratigraphic and structural framework of Ellesmerian and older sequences in Sadlerochit and Shublik Mountains, Arctic National Wildlife Refuge (ANWR), northeastern Alaska
Depositional setting, sequence stratigraphy, diagenesis and reservoir potential of a mixed-lithology, upwelling deposit: Upper Triassic Shublik Formation, Prudhoe Bay, Alaska
Conference
·
Sun Mar 31 23:00:00 EST 1985
· Am. Assoc. Pet. Geol., Bull.; (United States)
·
OSTI ID:5969436
Stratigraphic and structural framework of Ellesmerian and older sequences in Sadlerochit and Shublik Mountains, Arctic National Wildlife Refuge (ANWR), northeastern Alaska
Conference
·
Sun Jan 31 23:00:00 EST 1988
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
·
OSTI ID:5720891
Depositional setting, sequence stratigraphy, diagenesis and reservoir potential of a mixed-lithology, upwelling deposit: Upper Triassic Shublik Formation, Prudhoe Bay, Alaska
Journal Article
·
Fri Sep 01 00:00:00 EDT 1995
· AAPG Bulletin
·
OSTI ID:159906
Related Subjects
02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALASKA
CARBONATE ROCKS
DEPOSITION
FEDERAL REGION X
FOSSILS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LIMESTONE
MESOZOIC ERA
NORTH AMERICA
PETROLEUM GEOLOGY
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SHALES
TRIASSIC PERIOD
USA
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALASKA
CARBONATE ROCKS
DEPOSITION
FEDERAL REGION X
FOSSILS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LIMESTONE
MESOZOIC ERA
NORTH AMERICA
PETROLEUM GEOLOGY
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SHALES
TRIASSIC PERIOD
USA