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Estimate of three-dimensional flexural-isostatic response to unloading; rock uplift due to late Cenozoic glacial erosion in the Western United States

Jon D. Pelletier
Estimate of three-dimensional flexural-isostatic response to unloading; rock uplift due to late Cenozoic glacial erosion in the Western United States
Geology (Boulder) (February 2004) 32 (2): 161-164

Abstract

Alpine glacial erosion may strongly influence mountain building through erosionally driven rock uplift and relief production. In this paper I use a three-dimensional model for the flexural-isostatic response of the lithosphere to estimate the potential for late Cenozoic erosionally driven rock uplift in the western United States. Specifically, I present a map of the ratio of erosionally driven rock uplift to glacial erosion for this region. This ratio depends on the magnitude of the flexural bending stresses that act to limit differential uplift. The map is created by constraining the extent of Pliocene-Quaternary alpine glacial erosion in the western United States and solving the three-dimensional flexure equation for the resulting lithospheric deflection. The map indicates that the magnitude of erosionally driven uplift depends sensitively on the size of the glaciated range and the presence of nearby glaciated ranges. As a result, regional-scale patterns must be considered in order to correctly estimate local amounts of erosionally driven rock uplift. The ranges in the western United States with the greatest ratios of uplift to erosion are the San Juan Mountains and the Yellowstone Plateau-Absaroka Range, because these are extensively glaciated and have glaciated ranges nearby. In contrast, the Wind River Range and Sierra Nevada have ratios of uplift to erosion that are only half as large. These results identify which ranges likely underwent the greatest erosionally driven uplift and relief production and provide a widely applicable technique for modeling the flexural-isostatic response to loading and unloading in three dimensions.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 32
Serial Issue: 2
Title: Estimate of three-dimensional flexural-isostatic response to unloading; rock uplift due to late Cenozoic glacial erosion in the Western United States
Author(s): Pelletier, Jon D.
Affiliation: University of Arizona, Department of Geosciences, Tucson, AZ, United States
Pages: 161-164
Published: 200402
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 17
Accession Number: 2004-021724
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: sketch maps
N42°45'00" - N43°30'00", W109°30'00" - W108°30'00"
N43°30'00" - N45°00'00", W110°15'00" - W109°00'00"
N37°00'00" - N37°45'00", W107°30'00" - W106°30'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200407
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