HR: 11:35h
AN: T22B-06    [Abstracts]
TI: Ideas on the Cenozoic Evolution of the Colorado Plateau Mantle Based on Geophysical Observations, Mantle Xenoliths, Magmatic Patterns, and Rock Uplift and Exhumation
AU: * Roy, M
EM: mroy@unm.edu
AF: University of New Mexico, MSC 03-2040, 1 University of New Mexico, Albuquerque, NM 87131
AU: Selverstone, J
EM: selver@unm.edu
AF: University of New Mexico, MSC 03-2040, 1 University of New Mexico, Albuquerque, NM 87131
AU: Jordan, T
EM: tjordan@usc.edu
AF: University of Southern California, Zumberge Hall, USC, 3651 Trousdale Parkway, Los Angeles, CA 90089
AU: Kelley, S
EM: sakelley@ix.netcom.com
AF: New Mexico Institute of Mining and Technology, Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Soccorro, NM 87801
AU: Pederson, J
EM: bolo@cc.usu.edu
AF: Utah State University, Department of Geology, Logan, UT 84321
AU: Stockli, D
EM: stockli@ku.edu
AF: University of Kansas, 1475 Jayhawk Boulevard 120 Lindley Hall, Lawrence, KS 66045-7613
AU: Callahan, C
EM: ccallaha@unm.edu
AF: University of New Mexico, MSC 03-2040, 1 University of New Mexico, Albuquerque, NM 87131
AU: MacCarthy, J
EM: jkmacc@unm.edu
AF: University of New Mexico, MSC 03-2040, 1 University of New Mexico, Albuquerque, NM 87131
AB: The rock and surface uplift of the Colorado Plateau and its relative tectonic stability remain enigmatic features of the Cenozoic evolution of North America. In this work we bring together observations from a range of datasets: patterns of Tertiary magmatism, rock exhumation, and erosion, the composition and physical properties of mantle xenoliths hosted in Tertiary-age igneous rocks, and geophysical observations of present-day upper mantle seismic and buoyancy structure. We use these diverse datasets to develop ideas for the Cenozoic evolution of the Colorado Plateau, focussing on processes that may have modified (or are modifying) the upper mantle of the plateau and its surroundings. We will specifically address some of the salient physical and chemical consequences of possible removal of the Farallon slab in middle Tertiary time from beneath North America. The removal of the Farallon slab is generally thought to have triggered the voluminous, widespread, middle-Tertiary ignimbrite volcanism that affected the western US, including the margins (but not the interior) of the Colorado Plateau. We will present simple models of how Cenozoic rock and surface uplift of the Colorado Plateau could be driven by a combination of isostatic responses to erosion, the chemical and physical modification of the upper mantle during and following ignimbrite magmatism, and the thermal effects of slab removal and subsequent conductive relaxation of North America lithosphere.
DE: 8103 Continental cratons
DE: 8110 Continental tectonics: general (0905)
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: Fall Meeting 2005