2009 Portland GSA Annual Meeting (18-21 October 2009)
Paper No. 5-7
Presentation Time: 9:30 AM-9:45 AM

A LATEST PLEISTOCENE AND HOLOCENE CHRONOLOGY OF ALPINE GLACIATION FOR WESTERN NORTH AMERICA

MARCOTT, Shaun A.1, CLARK, Peter U.1, SHAKUN, Jeremy D.1, BROOK, Edward J.2, NOVAK, Anthony M.2, DAVIS, P. Thompson3, and CAFFEE, Marc W.4, (1) Departmet of Geosciences, Oregon State University, Corvallis, OR 97331, marcotts@geo.oregonstate.edu, (2) College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, (3) Department of Natural & Applied Sciences, Bentley University, 175 Forest St, Waltham, MA 02452-4705, (4) Department of Physics, Purdue University, 1396 PHYSICS BLDG, W. Lafayette, IN 47907-1396

We are developing a cosmogenic 10Be chronology of late-Pleistocene and Holocene alpine glaciation from sites across the western United States and southwestern Canada in order to address spatial and temporal glacier variability in response to postulated climate forcings. A number of studies have interpreted several Holocene glacial advances in western North America, but age control is based largely on relative dating techniques or limiting radiocarbon ages. Our 10Be chronology will provide new constraints on late-Pleistocene and Holocene climate change and their impact on the mass balance of western North American alpine glaciers. We present ~80 new 10Be ages from eight mountain ranges in the western United States and a single site in southwestern Canada. These initial results indicate that the majority of glacial deposits previously mapped as late Holocene are instead late Pleistocene or early Holocene. Our new 10Be ages imply retreat from moraine positions occurring at roughly 2.5, 9.0, 10.5, 11.5, 12.5, and 14.0 ka.

2009 Portland GSA Annual Meeting (18-21 October 2009)
General Information for this Meeting
Session No. 5
Quaternary Geology: Glaciation, Paleoclimate, and Landscape History
Oregon Convention Center: B114/115
8:00 AM-12:00 PM, Sunday, 18 October 2009

Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 34

© Copyright 2009 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.