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Late Quaternary paleoclimate of western Alaska inferred from fossil chironomids and its relation to vegetation histories

Quaternary Science Reviews

By:
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DOI: 10.1016/j.quascirev.2008.12.001

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Abstract

Fossil Chironomidae assemblages (with a few Chaoboridae and Ceratopogonidae) from Zagoskin and Burial Lakes in western Alaska provide quantitative reconstructions of mean July air temperatures for periods of the late-middle Wisconsin (~39,000-34,000 cal yr B.P.) to the present. Inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordination. Paleotemperature trends reveal substantial differences in the timing of climatic warming following the late Wisconsin at each site, although chronological uncertainty exists. Zagoskin Lake shows early warming beginning at about 21,000 cal yr B.P., whereas warming at Burial Lake begins ~4000 years later. Summer climates during the last glacial maximum (LGM) were on average ~3.5C° below the modern temperatures at each site. Major shifts in vegetation occurred from ~19,000 to 10,000 cal yr B.P. at Zagoskin Lake and from ~17,000 to 10,000 cal yr B.P. at Burial Lake. Vegetation shifts followed climatic warming, when temperatures neared modern values. Both sites provide evidence of an early postglacial thermal maximum at ~12,300 cal yr B.P. These chironomid records, combined with other insect-based climatic reconstructions from Beringia, indicate that during the LGM: (1) greater continentality likely influenced regions adjacent to the Bering Land Bridge and (2) summer climates were, at times, not dominated by severe cold.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Late Quaternary paleoclimate of western Alaska inferred from fossil chironomids and its relation to vegetation histories
Series title:
Quaternary Science Reviews
DOI:
10.1016/j.quascirev.2008.12.001
Volume
28
Issue:
9-10
Year Published:
2009
Language:
English
Publisher:
Springer
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
Geology and Environmental Change Science Center
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Science Reviews
First page:
799
Last page:
811