Accelerated retreat of northern James Ross Island ice streams (Antarctic Peninsula) in the Early-Middle Holocene induced by buoyancy response to postglacial sea level rise

• Published in: Earth and Planetary Science Letters
• Main Authors: Roman, Matěj, Nývlt, Daniel, Davies, Bethan, Braucher, Régis, Jennings, Stephen J.A., Břežný, Michal, Glasser, Neil, Hambrey, Michael, Lirio, Juan, Rodés, Ángel
• Other Authors: Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, Wales, Masaryk University Brno (MUNI), Centre for Quaternary Research, Royal Holloway University of London (RHUL), Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego ´ 5A, Warsaw 02–106, Scottish Universities Environmental Research Centre (SUERC), University of Glasgow-University of Edinburgh (Edin.), Operational Programme Research,Development, and Education – Project Postdoc@MUNI (No. CZ.02.2.69/0.0/0.0/16_027/0008360) at Masaryk University, NERC grant to N.Glasser: “Glacial history of the NE Antarctic Peninsula Region overcentennial to millennial timescales” (reference NE/F012942/1), andCzech Science Foundation (GACR) ˇ grant No. 22–20621O. The authorsappreciate the use of the Czech Antarctic Research Programme infrastructure, supported by the MEYS projects VAN 2021/1, VAN 2020/1,LM2015078, CZ.02.2.69/0.0/0.0/16_027/0008360, and CZ.02.1.01/0.0/0.0/16_013/0001708
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU]Sciences of the Universe [physics]; Antarc*; Antarctic; Antarctic Peninsula; Ice Sheet; James Ross Island; Ross Island
• Online Access: https://hal.science/hal-04628471; https://doi.org/10.1016/j.epsl.2024.118803

International audience The knowledge of dynamics and retreat patterns of marine-based ice streams under multiple stressors are offoremost importance for predicting Antarctic Ice Sheet response to climate changes. The Holocene palaeoglaciological record of former ice streams draining the northeast Antarctic Peninsula can elucidate the influences of changes in atmospheric and oceanic circulation and sea-level oscillations on the ice thinning andgrounding line retreat. Here, terrestrial cosmogenic nuclide (TCN) dating of erratic boulders across the JamesRoss Island group sheds light on the pattern and timing of the ice recession along the two main arteries of thepalaeo-ice drainage: Croft Trough and Prince Gustav Channel. The approach of using paired 10Be-26Al nuclidesenabled an assessment of cosmogenic isotope inheritance and complex burial-exposure history, notably on thehigh-altitude volcanic mesas. The TCN ages suggest that the Prince Gustav Channel Ice Stream was thinning fromat least ~12 ka, with subsequent separation of the Antarctic Peninsula and James Ross Island ice masses by 10–8ka. The transition from grounded ice to open marine conditions in the Croft Trough occurred rapidly at 8.6–7.2ka, following the Early Holocene Warm Period, concomitant with eustatic and relative sea-level rise and incursions of warmer circumpolar waters. Grounding line retreat was possibly further accelerated by buoyancyresponse of thinning ice stream to low-gradient bed topography. The lessons of rapid deglaciation of James RossIsland palaeo-ice streams may provide analogues for recent or future intensification of pressures on Antarcticglaciers.