Leaf wax δ2H and varve-thickness climate proxies from proglacial lake sediments, Baffin Island, Arctic Canada
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We present a multiproxy paleoclimate record using leaf wax hydrogen isotopes (δ2Hwax) and varve thickness from Arctic proglacial lake sediments. We also provide one of the first evaluations of the utility of δ2Hwax as a paleoclimate proxy in Arctic proglacial lakes. We compare varve thickness and δ2Hwax at sub-decadal resolution from 1948 to 2004 AD, and at sub-centennial resolution from 1450 to 2004 AD. Varve thickness and δ2Hwax both contain large interannual variability and are anti-correlated during the late twentieth century, suggesting that both proxies respond rapidly, but by different mechanisms, to catchment-scale forcings. At longer time scales, varve thickness exhibits a strong response to Little Ice Age cooling (1661–1827 AD in this record) but does not show evidence for twentieth century warming recorded throughout the Arctic. δ2Hwax does record regional-scale temperature changes, with more 2H-depleted values during the Little Ice Age and an abrupt change to more 2H-enriched values in the twentieth century. This corresponds well with a recent Arctic-wide temperature reconstruction in which the seventeenth century is the coldest interval, and the twentieth century is the warmest interval. Our results suggest that δ2Hwax is a promising proxy that can be applied at high resolution in proglacial Arctic lakes.
KeywordsArctic climate Baffin Island Biomarker Compound-specific isotopes Holocene Leaf wax Proglacial lake Varve
We thank N. Young, J. Qillaq, S. Gearhard, M. Badding, and N. Michelutti for help in the field. We also thank J. Qillaq for information about modern Ayr Lake conditions. We thank M. Ketterer, R. Tarozo, J. Tierney, and D. Murray for their help in the lab. S. Gearhard, G. Liston and participants in the Silalirijiit Project graciously provided us with their weather station data. We thank D. Kaufman (editor) and three reviewers for helpful comments. Funding for this project was provided to JPB by NSF ARC-0909334 and to YH by NSF EAR-0902805. EKT was supported by an NSF Graduate Research Fellowship. SM’s varve thickness research was funded in part by a grant from the University at Buffalo Mark Diamond Research Fund.
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