Late Paleozoic Ice Age glaciers shaped East Antarctica landscape

• Published in: Earth and Planetary Science Letters
• Main Authors: Rolland, Yann, Bernet, Matthias, Van Der Beek, Peter, Gautheron, Cécile, Duclaux, Guillaume, Bascou, Jerôme, Balvay, Mélanie, Héraudet, Laura, Sue, Christian, Ménot, René-Pierre
• Other Authors: Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet Saint-Étienne (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU]Sciences of the Universe [physics]; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Antarctic; East Antarctica; George V Land; Terre Adélie; Terre-Adélie; Antarc*; Antarctica; Ice Sheet
• Online Access: https://hal.archives-ouvertes.fr/hal-01925658; https://hal.archives-ouvertes.fr/hal-01925658/document; https://hal.archives-ouvertes.fr/hal-01925658/file/papier_thermochro_Antarctique-EPSL.final.pdf; https://doi.org/10.1016/j.epsl.2018.10.044

International audience The erosion history of Antarctica is fundamental to our understanding of interlinks between climate and glacier dynamics. However, because of the vast polar ice sheet covering more than 99% of Antarctica land mass, the continental surface response to glacial erosion remains largely unknown. Over the last decade the subglacial topography of Antarctica has been imaged by airborne radar surveys. These studies revealed high and complex sub-glacial relief in the core of the East Antarctic shield, interpreted as resulting from rifting episodes and low long-term erosion rates, or repeated large-scale glacial retreats and advances. In East Antarctica, thermochronology studies have revealed a spatially localized Cenozoic erosion starting after 34 Ma, with a maximum denudation of 2 km in the Lambert Trough. Low pre-glacial erosion rates before 34 Ma have been inferred since the Permian period, following a phase of significant (>2 km) erosion during the Late Paleozoic between 350 and 250 Ma. However, the exact extent, magnitude and significance of this Late-Paleozoic erosion phase remain elusive. Here we show that homogeneous exhumation occurred at the scale of the Terre Adélie margin of East Antarctica in response to major glacial erosion during the Late Paleozoic Ice Age (LPIA). Our data require homogeneous exhumation and >4 km erosion between 340 and 300 Ma, along a 600-km profile along the Terre Adélie-George V Land coast. The data are inconsistent with either exhumation during Permian rifting, or with significant (>1.5 km) Cenozoic glacial erosion, which requires LPIA glaciers to have been temperate, promoting glacial sliding, erosion and sediment transfer, even at high latitudes, unlike in the present situation. La compréhension de l’histoire de l’érosion de l’Antarctique est fondamentale pour comprendre les liens entre les dynamiques glaciaires et climatiques, et notamment le comportement futur de la calotte en réponse au réchauffement et son impact sur le niveau marin. La réponse ...