Variable responses of western U.S. glaciers during the last deglaciation
- 1Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
- 2Department of Geosciences, Oregon State University, Corvallis, Oregon 97331, USA
- 3Department of Geology and Program in Environmental Science, Washington State University, Vancouver, Washington 98686, USA
- 4Department of Physics, PRIME Lab, Purdue University, West Lafayette, Indiana 47907, USA
Abstract
Cosmogenic 10Be exposure ages from moraines in the Wallowa Mountains, Oregon, identify two maximal late Pleistocene glaciations at 21.1 ± 0.4 ka and 17.0 ± 0.3 ka and a minor glacial event at 10.2 ± 0.6 ka. Our new high-resolution chronology, integrated with other well-dated glacial records from the western United States, demonstrates substantial differences in the synoptic responses of western U.S. glaciers to climate forcing associated with the global Last Glacial Maximum and subsequent millennial-scale events originating in the North Atlantic region. These variable synoptic glacier responses identify large changes in the relative contributions of regional to global controls on the climate of the western United States that accompanied the deglaciation.
Footnotes
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↵*Present addresses: Licciardi—Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA; joe.licciardiunh.edu. Sharma—Discovery Park, Purdue University, West Lafayette, Indiana 47907, USA
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↵GSA Data Repository item 2004013, methods, measurements, and uncertainties, Table DR1 (beryllium data for Wallowa moraines), and Figure DR1 (glacial deposits in Glacier Lake cirque area), is available online at www.geosociety.org/pubs/ft2004.htm, or an request from editinggeosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, USA.
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- Accepted October 7, 2003.
- Received May 27, 2003.
- Revision received October 1, 2003.
- Geological Society of America
