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Fingerprinting of glacial silt in lake sediments yields continuous records of alpine glaciation (35–15 ka), western USA

Authors :
Steven M. Colman
Richard L. Reynolds
Joseph G. Rosenbaum
Source :
Quaternary Research. 78:333-340
Publication Year :
2012
Publisher :
Cambridge University Press (CUP), 2012.

Abstract

Fingerprinting glacial silt in last glacial-age sediments from Upper Klamath Lake (UKL) and Bear Lake (BL) provides continuous radiocarbon-dated records of glaciation for the southeastern Cascade Range and northwestern Uinta Mountains, respectively. Comparing of these records to cosmogenic exposure ages from moraines suggests that variations in glacial flour largely reflect glacial extent. The two areas are at similar latitudes and yield similar records of glacial growth and recession, even though UKL lies less than 200 km from the ocean and BL is in the continental interior. As sea level began to fall prior to the global Last Glacial Maximum (LGM), existing glaciers in the UKL area expanded. Near the beginning of the global LGM (26.5 ka), the BL record indicates onset of glaciation and UKL-area glaciers underwent further expansion. Both records indicate that local glaciers reached their maximum extents near the end of the global LGM, remained near their maxima for ~ 1000 yr, and underwent two stages of retreat separated by a short period of expansion.

Details

ISSN :
10960287 and 00335894
Volume :
78
Database :
OpenAIRE
Journal :
Quaternary Research
Accession number :
edsair.doi...........8e0a64ef889527a3cbe6297364f3b64d