A PALEOCEANOGRAPHIC PERSPECTIVE ON THE FINAL DAYS OF GLACIAL LAKE RUSSELL, PUGET SOUND, WASHINGTON
Preliminary analysis of CT-scan imagery, Multi-sensor Core Logger data (gamma density, magnetic susceptibility), and scanning X-ray Fluorescence (XRF) geochemical data indicate that these cores capture the deglacial Pleistocene/Holocene transition and ultimate retreat of the Puget Lobe of the Cordilleran ice sheet, including inputs from the drainage of Glacial Lake Russell. Downcore δ18O on benthic foraminifera places the timeline of regional glacial retreat into global context, while radiocarbon dates constrain the absolute timing of these events. Salinity estimated from δ18O values on planktonic foraminifera as well as benthic and planktic foraminiferal faunal data identify major changes in ambient ocean conditions and fresh-water discharge to the ocean. This study will provide insight into the retreat of the southwestern Cordilleran Ice sheet and the impact of regional freshwater inputs associated with drainage of Glacial Lake Russell on the adjacent marine environment.