Award Date

1-1-1988

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

First Committee Member

Margaret N. Rees

Number of Pages

112

Abstract

A depositional-tectonic model is proposed for the reconstruction of a Miocene lacustrine basin in the southern Las Vegas Range, Nevada, that was fragmented during a period of extensional tectonism. The model suggests that the sediments were deposited in an isolated basin during initiation of normal faulting in the Sheep Range extensional allochthon 12 to 16 Ma. After 12 Ma, deposition in this basin was terminated by normal faulting followed by oroflexural rotation along the Las Vegas Valley shear zone; The unique Middle Miocene sequence is 335-m-thick and consists of interbedded nonmarine limestone, siltstone, sandstone, conglomerate, megabreccia, and volcanic ash. The formation represents deposition in a shallow, permanent lake 12 to 16 Ma. Post 12 Ma, the formation was faulted by north-striking, normal faults. Subsequently, oroflexural bending along the Las Vegas Valley shear zone, rotated the faults into their present northeast-striking orientation.

Keywords

Constraints; Middle Miocene; Miocene; Nevada; Range; Sedimentological; Southern; Tectonism; Vegas; Las Vegas

Controlled Subject

Geology

File Format

pdf

File Size

3727.36 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Permissions

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Identifier

https://doi.org/10.25669/xzfv-h1j7


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