ICE SHEET/OCEAN INTERACTIONS OBSERVED FROM LABRADOR SEA SEDIMENTS: THE LAURENTIDE ICE SHEET WITHIN THE GLOBAL CLIMATE SYSTEM

Heinrich Events are among the most studied paleoceanographic phenomena of the last climate cycle, yet our understanding of the dynamics of the Laurentide Ice Sheet (LIS) associated with these events is still relatively poor. Three piston cores from the Southern Labrador Sea: HU91-045-094 (50°12.26 N, 45°41.14 W, water depth 3448 m, length 10.99 m), MD95-2024 (lat/long: 50°12.40 N, 45°41.22 W water depth: 3539 m, length: 27.34 m) and MD99-2237 (50°12.93 N, 45° 41.03 W, water depth 3530 m, length 30.74 m) provide the most detailed marine records of LIS instability over the last 120 kyr. In these cores, rapidly deposited detrital layers, intercalated within background hemipelagic sediments, provide proximal analogues to the North Atlantic Heinrich layers. The cores also contain other rapidly deposited detrital layers that are not documented in the North Atlantic IRD belt. As in other records more proximal to Hudson Strait, the sediment within these detrital layers was delivered by a variety of sedimentation processes with only a limited amount IRD. Using the now robust Labrador sea paleointensity assisted chronostratigrahy (PAC), synchronized to GISP2 chronology, these southern Labrador Sea records provide a detailed lithostratigraphic template that can be correlated to the detailed observations of LIS instability made by John Andrews and Colleagues in and around Hudson Strait. As a result, the records of this instability and a better understanding of LIS behavior can be placed in a global paleoclimatic context to assess the role of the LIS both as a driver and a passenger within the global climate system.