A Be-10 chronology of lateglacial and Holocene mountain glaciation in the Scoresby Sund region, east Greenland: implications for seasonality during lateglacial time

Publication Type  Journal Article
Year of Publication  2008
Authors  Kelly, M. A.; Lowell, T. V.; Hall, B. L.; Schaefer, J. M.; Finkel, R. C.; Goehring, B. M.; Alley, R. B.; Denton, G. H.
Journal Title  Quaternary Science Reviews
Volume  27
Issue  25-26
Pages  2273-2282
Journal Date  Dec
ISBN Number  0277-3791
Accession Number  ISI:000262130000002
Key Words  abrupt climate-change; situ cosmogenic nuclides; younger dryas; ice-sheet; snow accumulation; oxygen-isotope; north-atlantic; arctic canada; baffin-island; polar ice

Thirty-eight new cosmogenic (Be-10) exposure ages from the Scoresby Sund region of east Greenland indicate that prominent moraine sets deposited by mountain glaciers date from 780 to 310 yr, approximately during the Little Ice Age, from 11660 to 10 630 yr, at the end of the Younger Dryas cold interval or during Preboreal time, and from 13 010 to 11630 yr, during lateglacial time. Equilibrium line altitudes (ELAs) interpreted from lateglacial to Early Holocene moraines indicate summertime cooling between similar to 3.9 and 6.6 degrees C relative to today's value, much less than the extreme Younger Dryas cooling registered by Greenland ice cores (mean-annual temperatures of similar to 15 degrees C colder than today's value). This apparent discrepancy between paleotemperature records supports the contention that Younger Dryas cooling was primarily a wintertime phenomenon. Be-10 ages of lateglacial and Holocene moraines show that mountain glaciers during the Little Ice Age were more extensive than at any other time since the Early Holocene Epoch. In addition, 10Be ages of lateglacial moraines show extensive reworking of boulders with cosmogenic nuclides inherited from prior periods of exposure, consistent with our geomorphic observations and cosmogenic-exposure dating studies in other Arctic regions. (C) 2008 Elsevier Ltd. All rights reserved.


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URL  <Go to ISI>://000262130000002
DOI  DOI 10.1016/j.quascirev.2008.08.004