HR: 11:50h
AN: C52A-07    [Abstracts]
TI: Slow Erosion by a Fast Glacier
AU: * Huerta, A D
EM: ahuerta@geosc.psu.edu
AF: The Pennsylvania State University, Department of Geosciences, University Park, PA 16802, United States
AU: Winberry, J P
EM: pwinberr@geosc.psu.edu
AF: The Pennsylvania State University, Department of Geosciences, University Park, PA 16802, United States
AB: The dramatic imprints left on landscapes by Quaternary glaciations provide abundant evidence that glaciers can be efficient erosive agents. Understanding their erosive capability is key to unravelling the complex coupling of climate and the dynamics of the solid earth. Recent studies have focused on quantifying rates of glacial erosion to provide key data for understanding the physics that drives glacial erosion. While these studies concur that glacial erosion can outpace fluvial erosion, the magnitude of the measured erosion rates varies from ≫10 to <1.0 mm/yr. This discrepancy is, in part, because these studies estimate erosion rates over vastly different spatial and time scales. One excellent region for addressing the long-term, orogen-scale impact of glaciers on the landscape is the tectonically quiescent Transantarctic Mountains (TAM) that have been glaciated since ~34 Ma. Recent geomorphic investigations in the region of Byrd Glacier (the largest glacier in the TAM) indicate that the current geomorphology reflects ancient fluvial and tectonic processes active in the Cretaceous through Eocene, suggesting minimal reshaping of the landscape by glacial processing during the past ~34 Ma. These geomorphic conclusions are supported by new apatite fission track thermochronology from the valley wall of the Byrd Glacier that show that average erosion rates have been minimal since onset of glaciation (≪ 1 mm/yr). In light of the high ice velocities of the Byrd Glacier, these surprisingly low erosion rates challenge the current paradigm that erosion rate simply scales with ice flux. These results indicate that critical physics is missing from our glacial erosion laws.
DE: 0720 Glaciers
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1824 Geomorphology: general (1625)
DE: 1827 Glaciology (0736, 0776, 1863)
DE: 9310 Antarctica (4207)
SC: Cryosphere [C]
MN: 2007 Fall Meeting