RECONSTRUCTING DETAILED PROGLACIAL LAKE SEDIMENTATION AND CLIMATE USING MULTIPLE CORES FROM BIG ROUND LAKE, NORTHEASTERN BAFFIN ISLAND, ARCTIC CANADA

Big Round Lake (BRD) is a proglacial lake located on northeastern Baffin Island, Arctic Canada. This 36-meter-deep lake is fed by glacial meltwater from an inflow channel to the east and drains from an outflow channel to the west. Cores of the upper 20-40 cm of lake sediment were taken along a transect from the inflow to the deep basin. BRD contains annually laminated sediment (varves), which has been analyzed in order to relate varve thickness to past climate change. Typically, one core is taken from a site for paleoclimate research as a representative of sedimentation within an entire lake. Cores taken along the transect have been compared to one another as a test of this approach. Magnetic susceptibility, organic matter content (loss-on-ignition), and plutonium data were all used to compare the cores. Known dates in the plutonium record are 1952 (start of nuclear testing) and 1963 (peak of nuclear testing). These dates have been used as time markers for determining age versus depth in individual cores and to correlate between cores. The depth to these time markers is greater near the inflow and shallower away from the inflow. A higher sedimentation rate near the inflow would account for this trend. Varve thicknesses in each core will be measured and presented. Although the practice of analyzing one core as a general representative of an entire lake basin is supported by this research, multiple cores taken from one lake allow for a more detailed view of lake sedimentation.