Monday, March 29, 2010, 12:00PM - 1:00PM
Full title: "LGM-to-Present Greenland Ice Sheet history in the Disko and Umanak systems of West Greenland."
Recent observations suggest that the Greenland Ice Sheet (GIS) may have entered a state of rapidly increasing negative mass balance, which is a major concern, because the GIS stores enough fresh water to raise global sea level by c. 6.5 m. An understanding of the longer-term Late Quaternary-Holocene history of the GIS and its ice streams, and the ice sheet response to past climate would facilitate modeling of its response to future climate warming. Until recently, the late Quaternary and Holocene history of the GIS and its behavior during past warm climate intervals have been limited to studies of the ice-free land areas between the present-day ice sheet margin and the ocean, leaving the history of the 200 km wide shelf areas beyond the present day coast open to question. Marine geophysical and sediment core studies are beginning to make significant contributions to the knowledge of the glacial history, providing constraints on the Last Glacial Maximum extent of the GIS, the timing of deglaciation, and continuous records of the environmental and paleoceanographic conditions from deglaciation through the Holocene. This talk will present the first results from JR175, a geophysical and coring expedition to the Disko and Umanak systems of Western Greenland in late summer of 2009 on the British Antarctic Survey research ship, RRS James Clark Ross. Results of multibeam swath bathymetry, radiocarbon dating, and sediment cores from the trough-mouth fans on the contintental slope which were active during the LGM, along the shelf troughs that once served as ice-stream conduits, to the modern calving margin of the GIS will be shown (along with some nice photos!).