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Rapid Glacial Erosion at 1.8 Ma Revealed by ^4He/^3He Thermochronometry

Shuster, David L. and Ehlers, Todd A. and Rusmore, Margaret E. and Farley, Kenneth A. (2005) Rapid Glacial Erosion at 1.8 Ma Revealed by ^4He/^3He Thermochronometry. Science, 310 (5754). pp. 1668-1670. ISSN 0036-8075. http://resolver.caltech.edu/CaltechAUTHORS:20121120-142240847

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Abstract

Alpine glaciation and river incision control the topography of mountain ranges, but their relative contributions have been debated for years. Apatite ^(4)He/^(3)He thermochronometry tightly constrains the timing and rate of glacial erosion within one of the largest valleys in the southern Coast Mountains of British Columbia, Canada. Five proximate samples require accelerated denudation of the Klinaklini Valley initiating 1.8 ± 0.2 million years ago (Ma). At least 2 kilometers of overlying rock were removed from the valley at ≥5 millimeters per year, indicating that glacial valley deepening proceeded ≥6 times as fast as erosion rates before ∼1.8 Ma. This intense erosion may be related to a global transition to enhanced climate instability ∼1.9 Ma.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1126/science.1118519 DOIUNSPECIFIED
http://www.sciencemag.org/content/310/5754/1668PublisherUNSPECIFIED
Additional Information:© 2005 American Association for the Advancement of Science. Received for publication 8 August 2005; accepted for publication 7 November 2005. We thank G. Woodsworth for assistance in sample collection and providing access to the Digital Elevation Model used in Fig. 1 through collaboration with the Geologic Survey of Canada. We also thank J. M. Sisterson for help with the proton irradiation, L. M. Hedges for help with sample preparation, and M. S. Densmore. This work was supported by NSF grants EAR-0408526 and 0309779.
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Funding AgencyGrant Number
NSFEAR-0408526
NSFEAR-0309779
Record Number:CaltechAUTHORS:20121120-142240847
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20121120-142240847
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35581
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:21 Nov 2012 00:21
Last Modified:27 Dec 2012 03:02

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