Structural complexities that control localization of Mississippian shale-generated oil prospects in eastern Great Basin, Utah and Nevada
Mesozoic anticlinoria and synclinoria determine gross regional surface and subsurface distribution of Mississippian source rock shales. The original thicknesses of the shales are preserved only in the synclinoria. Over anticlinoria and on their flanks, shales were not deposited or were thinned by Late Jurassic to Early Cretaceous younger-over-older denudation thrusting. The Pilot, Joana, Chainman, and lower Ely Formations were eliminated either entirely or partly by shearing. The Chainman decollement zone is intruded by 110 m.y.-old quartz monzonite and 35 m.y.-old quartz latities within many mining district areas. In the synclinoria areas, post-Oligocene block faulting has produced a mosaic of horsts and grabens. In many places on the horst blocks, the Oligocene volcanics and the late Paleozoic sequence are removed by erosion, but in the graben blocks the entire Paleozoic and volcanic sequences are preserved in the subsurface. These graben blocks still contain complete subsurface sections of the Mississippian source rock shales. The block-faulted mosaic is outlined by an older northeast fault set that displaced the sub-Miocene volcanic terrane in the valleys and refracted through the Paleozoic bed rock of the ranges. A younger set of normal faults outlines the geomorphology of the mountain blocks, bajadas, and playas. Geomorphology, gravity, and magnetic surveys help define the suballuvial pattern of the fault mosaic.
- Research Organization:
- W and W Partners, Holladay, UT
- OSTI ID:
- 5589759
- Report Number(s):
- CONF-8408161-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 68:7; Conference: Energy and More in '84, Salt Lake City, UT, USA, 27 Aug 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NEVADA
PETROLEUM DEPOSITS
SOURCE ROCKS
UTAH
ANTICLINES
GEOLOGIC FAULTS
MISSISSIPPIAN PERIOD
SEDIMENTARY BASINS
SHALES
FEDERAL REGION IX
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MINERAL RESOURCES
NORTH AMERICA
PALEOZOIC ERA
RESOURCES
ROCKS
SEDIMENTARY ROCKS
USA
020200* - Petroleum- Reserves
Geology
& Exploration