A REFINED MODEL OF THE LAST DEGLACIATION EVENT OF THE CURRENT ICE-AGE: ICE-5G

During the decade that has passed since publication of the ICE-4G model of Wurm-Wisconsin deglaciation, a significant quantity of high quality new data has been compiled which requires that this model be refined. These new data include critical observations of the LGM margins of the ice sheet that extended from the Barents Sea across Novaya Zemlya into the present Kara Sea, observations that have been compiled by the European QUEEN Group. Of equal importance have been the constraints on the LGM form of the Greenland Ice Sheet based upon the work of the European EISMINT project. Although of relatively minor global impact, the new work that has been completed in Britain to provide direct trim-line based estimates of the thickness of the LGM Scottish Ice Sheet has also been extremely informative. Of paramount importance importance, however, is most probably the new observations that have been forthcoming based upon absolute gravity and VLBI observations that are requiring a massive re-organization of the topography of the Laurentide Ice Sheet (LIS) itself. These observations have required us to recognize that the LGM form of the LIS was multi-domed rather than consisting of a single dome centred over Hudson Bay. In the ICE-5G reconstruction to be described in this paper, the Hudson Bay is covered by relatively thin ice, the time averaged thickness of which is controlled by the intense ice stream that flowed through Hudson Strait. This multi-domed form has now been predicted on a priori grounds using a modern three-dimensional thermo-mechanical model of ice sheet evolution.