Kinematics of faulting in Mine Mountain area of southern Nevada: Evidence for pre-middle Miocene extension

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

OSTI ID:5019060

Hudson, M R; Cole, J C ^[1]

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1. Geological Survey, Denver, CO (United States)

Structural analysis has revealed widespread extension associated with discontinuous fault segments previously considered to represent a Mesozoic thrust in the Mine Mountain area, Nevada Test Site, of southern Nevada. Complex fault and stratigraphic relations characterize allochthonous Ordovician to Devonian dolomite and local quartzite that are in fault contact above less deformed (but anticlinally arched) Mississippian siltstone in this area. Although initial juxtaposition of the older and younger rocks probably occurred during Mesozoic thrusting, most of 714 small faults examined at 25 sites within the upper plate reflect later extension. Normal faults that chiefly accommodated S.55[degree] W.-directed extension are earliest and widespread in the upper plate. These faults are concentrated above the basal fault surface and have dominantly top-to-the-southwest slip, except on the east-dipping flank of the keel where top-to-the-northeast slip is indicated. These relations suggest that the upper plate was extended mostly in place after or, permissibly, during development of the lower plate anticline. Faults that accommodated S.55[degree] W.-directed extension are unconformably overlain by middle Miocene volcanic rocks; younger faults that accommodated northwest-directed extension are also interpreted to predate middle Miocene volcanism, although a depositional onlap relation is not preserved. Deformation at Mine Mountain may have been coeval with Oligocene to early Miocene extension that is well known in areas farther north and south in the Basin and Range province but poorly documented in southern Nevada. The authors cannot preclude, however, that extension might have occurred within upper structural levels of the Mesozoic Sevier hinterland.

• OSTI ID: 5019060
• 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

Related Subjects

58 GEOSCIENCES
GEOLOGIC FAULTS
GEOLOGY
GEOMETRY
NEVADA TEST SITE
CARBONATE ROCKS
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
MIOCENE EPOCH
NEVADA
STRATIGRAPHY
TECTONICS
CENOZOIC ERA
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MATHEMATICS
NATIONAL ORGANIZATIONS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
TERTIARY PERIOD
US DOE
US ORGANIZATIONS
USA
580000* - Geosciences