Amino acid ratios in reworked marine bivalve shells constrain Greenland Ice Sheet history during the holocene

Jason P. Briner, Darrell S Kaufman, Ole Bennike, Matthew A. Kosnik

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Reconstructions of ice sheet fl uctuations during the Holocene, which encompassed cooler and warmer conditions than those that are captured in the historic record, help to elucidate ice margin sensitivity to climate change. We used amino acid geochronology to constrain the history of the western Greenland Ice Sheet margin during intervals of relative warmth in the middle Holocene. We measured the extent of amino acid racemization in 251 ice sheet-reworked marine bivalve shells from three locations spanning western Greenland. A signifi - cant relationship between shell age and the ratio of aspartic acid (Asp) isomers (Asp D/L) was revealed using Bayesian model fi tting on 20 radiocarbon-dated shell fragments. The range of Asp-inferred bivalve ages at each site corresponds well with independent records of early Holocene ice retreat and late Holocene ice advance. Furthermore, the frequency of Aspinferred bivalve ages from the three widely separated locations is nearly identical, with most ages between 5 and 3 ka, coinciding with optimum oceanic conditions. Because ice margin changes in western Greenland are tightly linked with oceanographic conditions, the distribution of reworked bivalve ages provides important information about relative ice margin position during smaller-than-present ice sheet confi gurations. This approach adds a new chronometer to our toolkit for constraining smaller-than-present ice sheet confi gurations and may have wide applicability around Greenland.

Original languageEnglish (US)
Pages (from-to)75-78
Number of pages4
JournalGeology
Volume42
Issue number1
DOIs
StatePublished - Jan 2014

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ice sheet
bivalve
amino acid
aspartic acid
Holocene
ice margin
shell
history
racemization
ice retreat
geochronology
ice
climate change

ASJC Scopus subject areas

  • Geology

Cite this

Amino acid ratios in reworked marine bivalve shells constrain Greenland Ice Sheet history during the holocene. / Briner, Jason P.; Kaufman, Darrell S; Bennike, Ole; Kosnik, Matthew A.

In: Geology, Vol. 42, No. 1, 01.2014, p. 75-78.

Research output: Contribution to journalArticle

Briner, Jason P. ; Kaufman, Darrell S ; Bennike, Ole ; Kosnik, Matthew A. / Amino acid ratios in reworked marine bivalve shells constrain Greenland Ice Sheet history during the holocene. In: Geology. 2014 ; Vol. 42, No. 1. pp. 75-78.
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