DETRITAL CARBONATE EVENTS IN BAFFIN BAY DURING THE LAST CLIMATIC CYCLE: THEIR TIMING VS. THE GREENLAND DANSGAARD-OESCHGER CYCLES AND NORTH ATLANTIC HEINRICH EVENTS

Ice sheets dynamics has received a lot of attention by the scientific community during the years as it represents a key component of the Earth’s climate system, playing an important role in parameters such as freshwater budget, sea-level fluctuations and ocean circulation. However, the detailed relationship between ice sheet behavior and late Quaternary climate variability such as Dansgaard-Oeschger cycles remains somewhat poorly understood. Here, we propose a multi-proxy study on a 7.4 m-long deep Baffin Bay sediment core (HU2008-029-016PC) to document northeastern Laurentide, Innuitian and Greenland ice margin activities during the last 115 ka. The core yielded a high-resolution record of detrital carbonate events (mostly dolomitic) associated with ice streaming episodes from Devon and Ellesmere islands in the northern area of Baffin Bay. Earlier studies assigned these Baffin Bay Detrital Carbonate (BBDC) layers to interstadial episodes. A paleomagnetic-based chronology now provides the means to better date these events. Grain size and mineralogical (XRD) analyses at 4 cm intervals together with high-resolution environmental magnetism and µXRF scanner proxies were used to link the sedimentary features to specific northeastern Laurentide - Innuitian and/or Greenland ice margin events. Cluster analysis indicates the recurrence of two major facies. Fine-grained and Ti-rich sediments indicate steady sedimentary supplies from Greenland ice margins. They contrast with the coarser detrital dolomite-rich layers associated with ice surging episodes from the northern Baffin Bay. We conclude that these episodes are mostly a record of local Innuitian ice dynamics in phase with Dansgaard-Oeschger events or of pervasive IRD delivery process due to fast flowing ice stream at distinct periods of glaciations during MIS5.