Cretaceous Olistostrome Model, Brooks Range, Alaska
The foothills area of the Brooks Range thrust belt in the area between the Itkillik River and the Etivluk River is composed dominantly of shallow, thrusted olistostrome sheets. Three olistostrome units can be recognized based on the dominant lithology of contained olistoliths and age of the matrix shales. The lower unit is Thithonian to mid-Valanginian in age and is characterized by abundant graywacke and turbidite, mafic rocks, black cherts, olistoliths of Norian-Rhaetic shales, Nuka sands, and glide sheets of Upper Devonian to Lower Mississippian rocks. Olistolights were derived from the Misheguk, Ipnavik, and Nuka Ridge allochthonous sequences. The middle unit is of late Valanginian age and has olistoliths of Norian shales; more abundant Upper Triassic chert; Otuk Formation; variegated, radiolarian, black and white cherts; Siksikpuk facies red, green and black shales; Upper Jurassic graywacke; and minor occurrences of mafic rocks. The unit is characterized by glide sheets of Triassic white and multicolor cherts. Olistoliths are derived from Nuka Ridge and Brooks Range sequences. The upper unit is Hauterivian in age and olistoliths included reworked material from all older units. Olistoliths are few and widely scattered. Isolated outcrops of white chert and conglomerate boulders are characteristic.
- Research Organization:
- Chevron Overseas Petroleum Inc., San Francisco, CA
- OSTI ID:
- 6319345
- Report Number(s):
- CONF-8505215-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 69:4; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Radiolarian biostratigraphy of the Otuk Formation in and near the National Petroleum Reserve in Alaska
Age and correlation of the Otuk formation, North-Central Brooks Range, Alaska
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALASKA
DEVONIAN PERIOD
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
LITHOLOGY
MESOZOIC ERA
MISSISSIPPIAN PERIOD
NORTH AMERICA
PALEOZOIC ERA
PETROLEUM GEOLOGY
ROCKS
SEDIMENTARY ROCKS
SHALES
TRIASSIC PERIOD
USA