News & Events

Grad student talk - Baffin Island ice caps: A story of rise and demise

Thursday, November 06, 2014, 4:30PM - 5:30PM

Speaker

Simon Pendleton

Location:

RL-1 room 269

Reconstructed glacier and ice cap histories in the Arctic play an important role in deciphering past climate forcing mechanisms and allow for a better understanding of current and future cryosphere changes in response to a changing climate. In order to better resolve these paleo-ice histories, we apply a number of different techniques to the ice caps and glaciers in the Penny Ice Cap region of Cumberland Peninsula, Baffin Island. The 14C age of in situ dead vegetation emerging from beneath cold-based ice is interpreted as the time when ice growth resulting from summer cold killed the vegetation. This "kill date" for each plant records when cold summers dropped regional snowline below the site, and remained below until our collection date. The kill dates also represent the last time that the climate was warm enough to expose the sampling location. Some of these emergent vegetation samples returned ages beyond the range of 14C, which suggests these locations have not been explosed for at least 50 ka, and likely not since the last interglaciation. We are currently applying in situ 14C dating from rocks at these locations to test this hypothesis. Additionally, we have collected dozens of rock samples for Al/Be cosmogenic dating to better model the complex exposure and burial histories of the ice caps and glaciers in the Penny Ice Cap region. This combination of techniques will provide an improved reconstruction of ice fluctuations and allow for a better understanding of regional and even local scale variations in climate forcings and ice response over the last 2 million years.