MICROFOSSIL AND SEDIMENT GRAIN SIZE RECORDS FROM INTERMEDIATE DEPTHS IN THE LABRADOR SEA

Modern-day convection in the Labrador Sea is the source of Labrador Sea Water (LSW), an intermediate-depth contribution to the Atlantic Meridional Overturning Circulation. Microfossil studies have shown that while LSW may have been present in the Labrador Sea during the early Holocene, persistent convection and production of LSW similar to modern conditions seems to have begun ~7 ka, possibly as part of a reorganization of North Atlantic deep circulation (Hillaire-Marcel et al., 2001; Hoogakker et al., 2011). We will present new benthic foraminiferal stable isotopic records from sediment cores at 1400-1900 m water depth, today lying in the core of LSW, as a record of changes in bottom water chemistry on the western margin of the southern Labrador Sea. New sortable silt grain size records from these cores will provide a dynamical proxy for bottom water current velocity changes. This multiproxy approach will allow us to reconstruct and characterize intermediate-depth circulation regimes associated with the Last Glacial Maximum, deglaciation, and Holocene.