Retreat and stabilization of a marine-based ice margin along a high arctic fjord-cross-shelf trough system

• Published in: Quaternary Science Reviews
• Main Authors: Couette, Pierre-Olivier, Lajeunesse, Patrick, Ghienne, Jean-François, Dorschel, Boris, Gebhardt, Catalina, Hebbeln, Dierk, Brouard, Etienne
• Other Authors: Université Laval Québec (ULaval), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association, Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen, Université du Québec à Montréal = University of Québec in Montréal (UQAM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Laurentide Ice Sheet; Baffin Island; Deglaciation; Holocene; Submarine landforms; Marine sediment cores; Abrupt climatic events; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Arctic; Canadian Arctic Archipelago; Arctic Archipelago; Baffin; Ice Sheet; Ice Shelf; Iceberg*
• Online Access: https://hal.science/hal-04066114; https://hal.science/hal-04066114/document; https://hal.science/hal-04066114/file/Couette_et_al_2023_ClydeDeglaciation_ManuscriptQSR.pdf; https://doi.org/10.1016/j.quascirev.2022.107949

International audience Multibeam bathymetric and seismostratigraphic data collected in the Clyde fjord-cross-shelf trough system (eastern Baffin Island, Canadian Arctic Archipelago) display glacial landforms and depositional assemblages that enable the identification of the maximal extent of the Laurentide Ice Sheet (LIS) margin and delineating the patterns and controls on its subsequent retreat. Additionally, 10 new sediment cores – from which seven radiocarbon ages were acquired – allow the recognition of depositional processes. Results show that, during the Last Glacial Maximum, the LIS margin extended almost to the edge of the continental shelf. Early deglaciation of the trough was marked by an initial ice-shelf collapse and rapid retreat of the ice stream, as evidenced by the absence of ice marginal landforms and the presence of extensive iceberg ploughmarks across a large portion of the outer trough. It was followed by a slow retreat and successive stabilizations of the ice margin that led to the deposition of recessional moraines and GZWs. Deglaciation of the fjord in the early Holocene occurred in an episodic style, whereby rapid retreat was punctuated by relatively long standstills that enabled major moraine formation. Long-term stabilizations of the ice margin in the Clyde fjord-cross-shelf trough system are interpreted to coincide with major climatic cooling events, such as the Younger Dryas and early Holocene cold reversals. Ages derived from sediment cores and previous work suggest that higher retreat rates correspond with periods of significant global sea level rise, suggesting that oceanic forcing exerted a minor control on the deglaciation. GZWs and large moraine ridges are observed at pinning points in the trough, indicating that the location of ice margin stabilizations was influenced by topography. The reconstruction of the deglaciation of the Clyde fjord-cross-shelf trough system allows us to refine deglacial models for similar systems of northeastern Baffin Island, in particular beyond the ...