AN ALKENONE-BASED HOLOCENE TEMPERATURE RECORD FOR SOUTHEASTERN GREENLAND FROM KULUSUK LAKE

The Arctic is currently undergoing rapid climate and cryosphere changes due to anthropogenic global warming. Abundant lakes around the perimeter of the Greenland Ice Sheet contain valuable sediment archives for paleoclimate reconstruction, critical for understanding the sensitivity of arctic regions to climate forcing. Here we report a 12,000 yr-long quantitative summer temperature record from Kulusuk Lake in southeastern Greenland, based on lacustrine alkenone paleothermometry. Lake Kulusuk (65.56° N, 37.12°W) is a 0.8 km2 cirque lake with a maximum depth of 69 m; the lake shares a catchment with two small glaciers. Previously published work (Balascio et al., 2015) reported a continuous record of minerogenic flux to Kulusuk Lake that was used to infer changes in the size of the cirque glaciers. The record documents glacier response across the 8.2 ka Event; glacier demise during the local Holocene Thermal Maximum; and glacier expansion across the Neoglacial period, marked by sporadic episodes of advance, beginning ca. 4.2 ka and culminating in the 20th Century, prior to the recent melting (Balascio et al., 2015). The new summer temperature record from Kulusuk Lake spans the past 12,000 years with sub- to multi-centennial-scale sampling resolution and reveals a temperature range for summer lakewater of up to 8 °C during the past 12,000 yrs. The highest resolution sampling was conducted across two intervals of rapid glacier change: ca. 8.2 ka and 3.9 ka. Inferred temperature and inferred glacier size show remarkable similarity at all time scales analyzed, highlighting the role of summer temperature in determining glacier size in this low arctic maritime region. We will compare these records to examine the sensitivity of small glaciers to temperature forcing and discuss the climate history of Kulusuk Lake with respect to the climate history and dynamics of the greater North Atlantic region.