Style and age of tectonism of Sadlerochit Mountains of Franklin Mountains, Arctic National Wildlife Refuge (ANWR), Alaska
The pre-Tertiary rocks north of the Franklin Mountains and south of the coastal plain in ANWR can be subdivided into two major structural units: (1) basement - Neruokpuk Formation, Nanook Limestone, and Katakturuk Dolomite - and (2) Lower Mississippian to Upper Cretaceous sedimentary rocks. Basement rocks underwent intense deformation prior to deposition of Lower Mississippian rocks; locally the contact is structural. Crustal shortening at the structural level exposed was accommodated primarily by concentric folding. Axial planes of major folds generally strike N70/sup 0/-90/sup 0/E and dip 50/sup 0/-80/sup 0/S, indicating north vergence, and can be subdivided into two groups: east-northeast trending and east trending. Major folds plunge subhorizontally and continue laterally for up to 10 mi (15 km). Exposed reverse faults show relatively small amounts of throw (<7500 ft or 2.5 km). Relative shortening decreases from greater than 41% at the northern margin of the Franklin Mountains to less than 16% in the Sadlerochit Mountains, amounting to approximately 14 mi (22 km) over 39 mi (64 km) of a north-south transect. Reverse/thrust faults are interpreted to sole out along a basal decollement. This detachment probably lies between the Neruokpuk Formation and overlying basement carbonate rocks between the Franklin and Sadlerochit Mountains, and ramps upward under the coastal plain. Field structurtal data of the study area, and well and seismic data of the area west of ANWR, constrain the principal post-Mississippian deformation, a phase of north-south compression to have occurred between the mid-Eocene and the present. East-trending folds suggest two deformational events. Relative timing of these events, based on field data, is equivocal.
- Research Organization:
- Gulf Oil Exploration and Production Co., Bakersfield, CA
- OSTI ID:
- 6131999
- Report Number(s):
- CONF-8505215-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 69:4; Conference: AAPG-SEPM-SEG Pacific section meeting, Anchorage, AK, USA, 22 May 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Related Subjects
ALASKAN NORTH SLOPE
GEOLOGIC HISTORY
TECTONICS
CRETACEOUS PERIOD
DOLOMITE
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
LIMESTONE
MISSISSIPPIAN PERIOD
ALASKA
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
FEDERAL REGION X
GEOLOGIC AGES
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MESOZOIC ERA
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
USA
020200* - Petroleum- Reserves
Geology
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