T216 Late Cretaceous to Early Paleogene Tectonic Development of the North American Cordillera II

Tuesday, 24 September 2019
1:30 PM - 5:30 PM
Room 231ABC, North Building

EOCENE ORIGIN OF OWENS VALLEY, CALIFORNIA

Paper number: T216-14
Program: Technical Sessions
Time: 4:50 PM – 5:05 PM

Authors

Abstract

Bedrock apatite and zircon (U-Th)/He data reveal an Eocene exhumation difference greater than four kilometers athwart Owens Valley, California near the Alabama Hills. This difference is localized at the eastern fault-bound edge of the valley between the Owens Valley Fault and the Inyo-White Mountains Fault. Time-temperature modeling of published data reveal a major phase of tectonic activity circa 54 Ma of a magnitude equivalent to the total modern bedrock relief of Owens Valley. Exhumation of the Inyo Mountains in early Eocene time at a rate of circa 1000 m/m.y. was contemporaneous with exhumation of the high Sierra Nevada immediately to the west at a much lower rate, roughly 50 m/m.y. in the vicinity of Mt Whitney. This difference was most likely accommodated by one or both of the Owens Valley and Inyo-White Mountains fault zones, requiring an Eocene structural origin of Owens Valley, 40 million years earlier than previously estimated.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-337792

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