Bedrock geology of the northernmost bulge of the Rocky Mountain Cordillera
- Dept. of Interior, Anchorage, AK (USA)
Analyses of LANDSAT imagery of the northernmost part of the Rocky Mountain Cordillera shows that rocks along the Alaska-Yukon border crop out in areally extensive predominantly curvilinear patterns. This area is a distinct and unique bulge in the mountain system where Upper Proterozoic sediments comprise most of the bedrock. At least two distinct and separate sedimentary successions are represented. The predominantly clastic Neruokpuk Group of the Inuvikian Sequence spans the international border. It exceeds 13,000 m of south-southwest-dipping, mildly metamorphosed slatey argillites, quartz arenites, argillitic limestones, and chert. Correlations indicate that there are eight units which crop out in elongate arcs. Coeval, south-dipping, predominantly carbonate rocks crop out in the Sadlerochit and Shublik Mountains and at Kikiktak Mountain. The Katakturak Formation is up to 2,400 m of dolomite, silicified dolomite, and stromatolitic limestone of Upper Proterozoic age. It is unconformably overlain by the massive limestones and shale of the Nanook Formation (U. Cambrian-U. Devonian). Undivided, the Nanook is 1,800 m thick with some sections removed by pre-Devonian erosion. As yet, the nature of the sedimentological relationships of these two successions is still unclear. CDP seismic shows two suites of pre-Ellesmerian, north-dipping and south-dipping reflectors beneath the Arctic Coastal Plain, north of the Sadlerochit Mountains. However, resolution deteriorates north of the Neruokpuk exposures, precluding attempts to tie seismically interpreted suites to outcrops. Also, exploration drilling has penetrated the north-dipping reflectors, but recovery and testing of interbedded argillites and limestones fails to resolve this enigmatic stratigraphic relationship.
- OSTI ID:
- 6064200
- Report Number(s):
- CONF-900702--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 74:6; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stratigraphic and structural framework of ellesmerian and older sequences in Sadlerochit and Shublik Mountains, Arctic National Wildlife Refuge (ANWR), northeastern Alaska
Depositional environments of Katakturuk Dolomite and Nanook Limestone, Arctic National Wildlife Refuge, Alaska
Related Subjects
580000* -- Geosciences
ALASKA
ARGILLITE
CANADA
CARBONATE ROCKS
DRILLING
EXPLORATION
EXPLORATORY WELLS
FEDERAL REGION X
GEOLOGIC FORMATIONS
GEOLOGY
LANDSAT SATELLITES
LIMESTONE
NORTH AMERICA
REMOTE SENSING
ROCKS
SATELLITES
SEDIMENTARY ROCKS
SHALES
STRATIGRAPHY
USA
WELL DRILLING
WELLS
YUKON TERRITORY