Testing an abrupt onset of the Little Ice Age

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The investigator will collect vegetation exposed along the margins of receding glaciers on Baffin Island, Canada and use radiocarbon dating to determine when it was frozen as glaciers advanced during the Little Ice Age. Samples from the same sites collected in 2005 suggest that ice may have expanded following volcanic activity. This study will address hypotheses about the rate of cooling by combining the distance of ice retreat since 2005 and difference in age of the mosses. A graduate student will participate in field work and prepare results of radiocarbon dating for publication.The goal of this project is to examine the rate of onset of persistent Little Ice Age (LIA) cold by dating 50 new samples from current ice margins from ice complexes in Baffin Island, Canada, and comparing them to similar collections from 2005. If LIA ice expansion was abrupt and persistent then dates on the new plants should be about the same age as the 2005 samples, 200 to 500 m distant. Whereas if summers slowly cooled over decades-to-centuries through the late Holocene, then the new dates will be significantly older than their 2005 counterparts. Collectively, these data will provide the most robust testing of an abrupt onset of LIA cold and will be of interest to the sea ice and climate modeling communities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.