Jurassic tectonic wedging and crustal block rotation, northern Sierra Nevada California

Conference · Thu Apr 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5022281

Harwood, D S; Griscom, A ^[1]

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1. Geological Survey, Menlo Park, CA (United States)

Rocks in the northern Sierra Nevada east of the Feather River peridotite belt (FRPB) and south of 39[degree]45 minutes N. strike NNW, dip steeply E and form an east-facing homoclinal section as much as 35km thick. The lower Paleozoic Shoo Fly Complex (SFC), the oldest and western-most unit in the homoclinal section, is faulted against the FRPB. Middle Jurassic volcanic rocks (Jv) at the top of the homoclinal section are down-faulted against Paleozoic rocks to the east along the Talbot fault (TF). A positive aeromagnetic anomaly and east-sloping gradient south of 39[degree]45 minutes N. indicate that the east contact of the FRPB dips about 45[degree]E. beneath the homoclinal section and extends to a depth of at least 10km. The contact between the buried FRPB and the homoclinal section is interpreted to be the roof thrust of an east-tapering wedge of serpentinized oceanic crust and upper mantle, probably emplaced in the Early and Middle Jurassic. Normal, west-down displacement on the Talbot fault, contemporaneous with east-vergent edging, resulted in eastward block rotation of the rocks above the wedge, syndepositional thickening of the Early and Middle Jurassic Sailor Canyon Formation (Jsc) relative to the coeval rocks east of the Talbot fault, and structural control for Middle Jurassic magmatism.

• OSTI ID: 5022281
• Report Number(s): CONF-9305259-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

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58 GEOSCIENCES
CALIFORNIA
GEOLOGIC FAULTS
GEOLOGY
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOMETRY
INCLINED STRATA
JURASSIC PERIOD
MAGMATISM
OCEANIC CRUST
SIERRA NEVADA COLORADO
DEVELOPED COUNTRIES
EARTH CRUST
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
MATHEMATICS
MESOZOIC ERA
MOUNTAINS
NORTH AMERICA
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