Folded Brookian thrust faults: Implications of three geologic/geophysical transects in the western Brooks Range, Alaska
- Geological Survey, Anchorage, AK (United States)
- Geological Survey, Denver, CO (United States)
Three geologic/geophysical transects in the Baird Mountains quadrangle in the western Brooks Range, Alaska, provide important insights on the nature of major structures in the area. Independently constructed geologic and geoelectric cross sections show strong correspondence between modeled audiomagnetotelluric resistivity data and mapped surface and inferred subsurface geologic structures. Major features reinforced by this correspondence include (1) the great thickness of the Maiyumerak mafic igneous rocks, (2) the north-northwestward vergence of the duplex involving sedimentary rocks of the Baird, Endicott, and Lisburne groups, (3) folding and steep normal fault truncation of the thrust faults in this duplex, (4) the westward dipping structural contact between mixed lower Paleozoic metasedimentary rocks exposed along Tukpahlearik Creek and the more homogeneous underlying quartz-mica schists of the schist belt, (5) a structural detachment beneath Proterozoic metasedimentary and meta-igneous basement rocks exposed in the northeastern part of the quadrangle, and (6) prominent west dipping structures that represent lateral ramps associated with northward transport of thrust sheets in the western Brooks Range during regional north directed Brookian deformation and west dipping structures that developed during a post-Brookian east-west compressional event which folded the imbricated thrust sheets as a package. Audiomagnetotelluric (AMT) data provide a useful and effective mapping tool in areas of limited to poor exposure and in areas affected by permafrost such as northwestern Alaska. Modeled AMT data supplemented geologic data and constrained geologic interpretations.
- OSTI ID:
- 5014504
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:B6; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Low-angle normal faults in the south-central Brooks Range fold and thrust belt, Alaska
Lower Paleozoic and Proterozoic rocks of Southern Brooks Range, Alaska
Related Subjects
580000* -- Geosciences
ALASKA
BASEMENT ROCK
DEFORMATION
DEVELOPED COUNTRIES
DIMENSIONS
ELECTRICAL SURVEYS
ELECTROMAGNETIC SURVEYS
FEDERAL REGION X
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOLOGIC SURVEYS
GEOLOGY
GEOMORPHOLOGY
GEOPHYSICAL SURVEYS
IGNEOUS ROCKS
MAGNETOTELLURIC SURVEYS
MAPPING
METAMORPHIC ROCKS
MOUNTAINS
NORTH AMERICA
PERMAFROST
RESISTIVITY SURVEYS
ROCKS
SCHISTS
SEDIMENTARY ROCKS
SURVEYS
TECTONICS
THICKNESS
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