Earth and Planetary Sciences ETDs

Publication Date

5-1-2015

Abstract

The effects of large-scale landsliding on the continental-scale Colorado River system in Grand Canyon remain poorly understood. This paper describes deep-seated bedrock landslides in the Surprise Valley area by combining detailed mapping, volume-balanced cross-sections, strath terrace heights, and cosmogenic burial dating of river deposits buried by landslides. Mapping shows failures involving ~1000 m Paleozoic section localized within basal shale detachments, dammed and diverted the Colorado River and local tributaries, and forced the creation of epigenetic gorges. Restored cross-sections show pre-existing paleotopography in Surprise Valley possibly created by an older, through-flowing Colorado River. Two individual landslide segments dated to ~1 Ma with large errors via cosmogenic burial age dating. Detachment height, long-term bedrock incision rates, and structural relationships suggest major failures events occurred at 3 Ma, 1 Ma, <<1 Ma. Paleotopography, groundwater, and bedrock incision likely drove landsliding rather than lava-dammed lakes downstream based on geochronology.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Huntoon, Peter

Second Committee Member

Crossey, Laura

Third Committee Member

Schmandt, Brandon

Project Sponsors

Geological Society of America, National Park Service, University of New Mexico Career Services, University of New Mexico Graduate and Professional Student Association

Language

English

Keywords

landsliding, Colorado River, Grand Canyon, cosmogenic burial age dating

Document Type

Thesis

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