Thursday, February 11, 2010, 4:30PM - 5:30PM
Stratospheric aerosols from explosive volcanism can alter the radiative balance of the planet. Eruptions are increasingly considered a powerful forcing on climate variability and tephras (volcanic ash), from Quaternary Icelandic volcanism, are used to independently date sediments across the British Isles and northwest Europe. Volcanoes in the Arctic System (VAST), a collaborative NSF grant awarded in 2007, seeks to better understand the role of volcanism in the Arctic System and to optimize the utility of tephra layers deposited across the Arctic. Here I present the current status of the VAST project including the extraction of tephras from distal lacustrine archives on Ellesmere Island, Baffin Island and Svalbard, Norway. Geochemical fingerprinting via microprobe analysis of these tephras is necessary to identify a volcanic source and potential eruption date, however this remains challenging when dealing with extremely small (20-50 micron) tephra shards. In addition to plume trajectory, the distribution and abundance of tephras within marine cores on the Icelandic and east Greenland shelf, provides insight into modes of delivery (primary air fall, glacial outwash, sea ice transport) and the associated climatic and oceanic conditions. The VAST project also attempts to evaluate the sensitivity of the Arctic System to high- and low-latitude eruptions through climate modeling and comparisons of model output to paleoenvironmental reconstructions. Future work includes developing tephra stratigraphy from sites on Baffin Island and northwest Iceland and investigating land-cover response to eruptions.