Date of Award

2024-08-01

Degree Name

Master of Science

Department

Geological Sciences

Advisor(s)

Jason W. Ricketts

Abstract

Laramide-style intracontinental deformation occurred throughout a large area in the western United States from the late Cretaceous through the Eocene. This event is largely investigated and viewed from classic exposures in Colorado and Wyoming, extending south to southern New Mexico. In this region the Laramide orogen merges with the Mexican fold and thrust belt (MFTB) and the northern limits of the Mexican orogen along a blurry boundary. In the Indio Mountain range in western Texas, Cretaceous sediments were deposited in the Jurassic-Cretaceous Chihuahua trough. They were inverted due to contraction and emplaced adjacent to the Diablo Plateau. This region lies within the boundary between the Laramide orogen and the MFTB, and deformation overlaps in time with both provinces. Bedding orientations divide the map area into five distinct structural domains. Structural domains are typically divided along major faults that are in the map area, such as the Bennett thrust fault and the younger Indio normal fault. Some of these structural domains are dominated by consistent bedding orientations, such as the region west of the Bennett thrust fault and east of the Indio fault, where bedding consistently strikes NW and dips moderately to the northeast. In other structural domains, bedding is extremely chaotic, such as in and around the Indio Mountains Research Station. Here, intense faulting and folding is concentrated in the immediate footwall of a sub-horizontal thrust fault. Cross-section reconstructions indicate that sub-horizontal thrust faults that lie to the west of the Indio fault are erosional remnants of the Bennett thrust fault and that this fault system has been dissected during the later Rio Grande rift extension. Contractional deformation in the map area is almost entirely characterized by displacement along shallowly dipping to horizontal thrust fault systems. Drone photogrammetry is utilized to help identify and resolve geometry in structurally complex areas. Together, these observations suggest that Laramide-age deformation in the Indio Mountains is more like deformation within the MFTB to the south and is unlike classic Laramide structures to the north.

Language

en

Provenance

Received from ProQuest

File Size

58 p.

File Format

application/pdf

Rights Holder

David w West

Included in

Geology Commons

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