HR: 14:55h
AN: H53I-05    [Abstracts]
TI: Response of a glaciated, steady-state critical wedge orogen to changes in climate
AU: Tomkin, J H
EM: tomkin@geol.lsu.edu
AF: Louisiana State University, Department of Geology and Geophysics, Baton Rouge, LA 70803 United States
AU: * Roe, G
EM: gerard@ess.washington.edu
AF: Washington State University, Department of Earth and Space Sciences, Seattle, WA WA 98195 United States
AB: There is much interest in determining the influence of climate change on orogen evolution, with recent analytical studies focusing on the influence of rivers on critical wedge systems (Hilley and Strecker, 2004; Whipple and Meade, 2004; Roe et al, in press). We present an analogous analytical study that examines the evolution of a glaciated orogen. Glacial erosion in this study is process based, where the rate of surface erosion is linked to the sliding velocity of the ice. The orogen is assumed to retain its critical angle, with matching rock uplift and erosion rates that are spatially non-uniform. Under these conditions, the rates of rock uplift are highest toward the edges of the orogen and lowest at the centre. Furthermore, the erosional flux is very sensitive to changes in climate. The total rate of erosion is approximately linearly sensitive to the precipitation rate, so precipitation and orogen width also scale approximately linearly. The distribution of rock uplift across the glaciated orogen is maximized at the glacier's equilibrium line altitude, which is largely controlled by temperature. These results stand in contrast to those expected for fluvially dominated orogens, as the rock uplift pattern is opposite and the sensitivity to climate change is much greater.
DE: 0720 Glaciers
DE: 0798 Modeling
DE: 1815 Erosion
DE: 8175 Tectonics and landscape evolution
SC: Hydrology [H]
MN: Fall Meeting 2005