TIMING OF NEOGLACIAL ADVANCES FROM RADIOCARBON DATING OF ICE-KILLED IN-SITU VEGETATION: CASE STUDIES FROM EAST AND NORTHWEST GREENLAND

Constraining the timing of past glacial fluctuations improves understanding of the climate system by evaluating the responses of glaciers to changing climate. Recent studies employed radiocarbon dating of glacier-entombed plants at receding ice margins to constrain past glacial advances. Here we investigate the timing of Neoglacial advances on Greenland in two case studies: local ice caps in the Scoresby Sund region of East Greenland and of the Greenland Ice Sheet at Prudhoe Dome in Northwest Greenland. We collected dead moss samples from cold-based ice margins in these two regions and dated them to constrain past periods of ice growth. We found evidence of ice advances at ~2550 cal yr BP and ~490 cal yr BP in Scoresby Sund. At Prudhoe Dome, three uncalibrated radiocarbon ages range from 155 to 190 cal yr BP; the calibrated age solutions range broadly over the Little Ice Age, from the late 1600s to the early 1900s. We use our results to test for synchronicity of the effects of cooling trends on glacier fluctuations with other locations in the Arctic. The timing of Neoglacial advances in Scoresby Sund coincide with records from West Greenland and Svalbard, indicating synchronicity of climate responses. The episodic glacial advances at Prudhoe Dome coincide with the cooling trend toward the end of the Little Ice Age. This project contributes to the expansion of our collective observational database on glacier history. Paired with established proxy records of changing temperature throughout the Holocene, the resultant glacial chronology adds insight into the climate forcings of glacier change.