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Detailed Reference Information |
Densmore, M.S., Ehlers, T.A. and Woodsworth, G.J. (2007). Effect of Alpine glaciation on thermochronometer age-elevation profiles. Geophysical Research Letters 34: doi: 10.1029/2006GL028371. issn: 0094-8276. |
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Low-temperature thermochronometers are widely used to quantify exhumation histories, typically by interpreting sample cooling age-elevation relationships. However, the effects of specific geomorphic processes on age-elevation profiles are seldom considered. We integrate apatite (U-Th)/He , apatite fission track, and zircon (U-Th)/He thermochronometry with numerical modeling to determine the effect of glacial erosion on an age-elevation profile from the heavily glaciated southern Coast Mountains, British Columbia. AHe data show a distinct break in slope in age-elevation between 1900--2100 m. We interpret this break in slope as an acceleration of erosion associated with the onset of alpine glaciation. We use a 3-D thermo-kinematic model to constrain pre- and synglacial erosion rates. Results indicate a preglacial erosion rate of ~0.4 mm/yr that accelerated by a factor of ~2 since ~6 Ma. We propose that glacial valley widening and deepening are responsible for the observed nonlinear AHe age-elevation profile. |
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Abstract |
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Keywords
Cryosphere, Glaciers, Cryosphere, Modeling, Geochronology, Thermochronology, Global Change, Geomorphology and weathering (0790, 1824, 1825, 1826, 1886) |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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