Researchers: T.A. Stahl, University of Canterbury; N.A. Niemi, University of Michigan; and M.P. Bunds, J. Andreini, and J.D. Wells, Utah Valley University.
Written by Linda Rowan
27 March 2020
Extensive geologic and geodetic data, especially terrestrial lidar and GPS, help decipher the dynamics of the eastern Basin and Range in the Sevier Desert, Utah. Over the past 30,000 years, the extension rates on faults near the Basin and Range-Colorado Plateau Transition Zone are much higher than in the Basin and Range. In the Sevier Desert, these high rates are due to periods of volcanism that caused magma-assisted rifting to activate these faults. The exquisite exposure of the geology in the desert enhances our understanding of the interplay of faulting and volcanism in dynamic plate regions.
The Basin and Range Province is a physiographic region in the western United States and northwestern Mexico defined by an alternating series of fault-bounded mountain ranges adjacent to flat arid valleys or basins. The topography is the result of the extension and thinning of the crust and uppermost mantle.
The Sevier Desert in Utah is part of the eastern Basin and Range. The desert environment provides excellent exposure of the geology. Using terrestrial lidar (light detection and ranging), GPS (Global Positioning System), geochronology, geomorphology and mapping, the timing and rate of extension along several faults can be determined and compared to paleoseismic, geodetic and geologic rates throughout the region.
The extension rates on faults in the eastern Sevier Desert are 0.1 to 0.8 millimeters per year over the past 10,000 to 30,000 years and are much higher than extension rates in the western desert. These rates are much higher than current rates of extension measured by GPS. Ages of events and modeling of GPS rates suggest that magma-assisted rifting along the faults can account for the past high rates of extension. The differences in the eastern and western desert suggest segmentation of the faulting into tectonic versus volcanic processes, making the Sevier Desert a key location to study such processes.
Stahl, T.A., Niemi, N.A., Bunds, M.P., Andreini, J., and Wells, J.D., 2020, Paleoseismic patterns of Quaternary tectonic and magmatic surface deformation in the eastern Basin and Range, USA, Geosphere, v. 16, no. 1, p. 435–455, doi: 10.1130/GES02156.1 .
Bunds, M., Andreini, J., Wells, J.D., and Stahl, T.A., 2019, High Resolution Topography of a Portion of the House Range Fault and Pleistocene Lake Bonneville Shorelines, Sevier Desert, Utah, USA: Distributed by OpenTopography, 10.5069/G9348HH6.
Basin and Range Province, Colorado Plateau, extension, magma-assisted rifting
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Last modified: 2020-03-30 14:44:23 America/Denver