The transition from marine to continental ice-fronts at retreating ice-sheet margins: lessons from the sedimentary archives of ice-front stabilizations

During a deglaciation, what happens formally at the time of the transition between marine ice fronts and terrestrial ice fronts? A stabilization often seems to occur, which can at least locally delay the deglaciation calendar. In the framework of the STABIL-ICE project, we want to test the hypothesis that the transition between marine and continental ice fronts induces an exceptional glacial behavior and sedimentary record -which mimic a signal of climatic deterioration-, and to characterize the processes at the origin of such stabilizations, the understanding of which will allow a better deciphering of the paleoglacial archives.

This research is based on the study of sedimentary records offered at outcrops by the post-glacial isostatic rebound. We are targeting the late Pleistocene-Lower Holocene successions of two similar sites in Disko Bay (Greenland, subject of the present IPEV project) and on the Quebec-Labrador margins (in collaboration with Laval University, Takuvik, Canada). These sites allow us to work on: (1) sedimentology, through a detailed analysis of depositional facies, morphostratigraphy and the temporal framework of glacial stabilization prisms; (2) methodology, for the calibration of age models by estimating cosmonuclide production rates in areas of significant glacio-isostatic rebound; (3) paleoglaciology, through the characterization (dynamics, ages) of the successive fronts of glacial retreat of the Laurentide and Greenland ice sheets; these three components being in fact linked two by two.