EARLY HOLOCENE EVOLUTION OF THE LAURENTIDE AND GREENLAND ICE SHEETS

Gauging the sensitivity of ice sheets to short-term climate variability is at the forefront of the scientific community’s and public’s interest because short-term ice-sheet change will drive 21^st century sea-level rise. Do ice sheets react abruptly to centennial-scale climate forcing, or are millennial-scale climate trends required to elicit a large-scale ice-sheet response? The early Holocene is of particular interest because both the Laurentide and Greenland ice sheets were rapidly retreating at this time within a climate regime that was as warm or warmer than today, yet at least two abrupt (centennial scale) cooling events interrupted this warmth. Reconstructions of ice-sheet behavior through the early Holocene provide an ideal test for assessing the sensitivity of ice sheets to temperature change, both warming and cooling, on human-relevant timescales. Here, we present initial results from an extensive ¹⁰Be dating campaign aimed at gauging how both the Laurentide and Greenland ice sheets evolved through the earth Holocene in the Baffin Bay region. We will present ¹⁰Be results from two locations on Baffin Island and southwestern Greenland that host prominent moraine sequences: a land-terminating margin, and a location that hosts moraines deposited by both an ice sheet and an independent mountain glacier system. We will highlight the similarities and differences between our reconstructed ice-margin chronologies on opposite sides of Baffin Bay.