Climate change and erosion: view from northern Scandinavia.

• Main Authors: Lenard, S.J.P., Gautheron, Cécile, Valla, Pierre, Bingen, Bernard, van Der Beek, Peter, Loget, Nicolas, Schwartz, Stéphane, Pinna Jamme, Rosella
• Other Authors: Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-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-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Institut für Geologie Bern, Universität Bern / University of Bern (UNIBE), Geological Survey of Norway (NGU), 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 ), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Lofoten; North Atlantic; Norwegian Sea; Tromsø
• Online Access: https://hal.science/hal-02930746

International audience The impact of Quaternary glaciations is evidenced worldwide in mountains and may have induced an increase of erosion rates (accelerated erosion). Low-temperature thermochronometry has been extensively used to unravel the complex links between climate and erosion. However, until now, only a limited number of studies detected accelerated erosion that can be interpreted as independent of tectonics and associated with climate change. In these conditions, will low-temperature yield any further advance in our understanding of the interactions between climate change and erosion? Here we discuss about a recent new and high-resolution apatite (U-Th-Sm)/He (AHe) dataset from northern Scandinavia, along the Norwegian Sea continental margin spanning from the Lofoten archipelago to the Tromsø area (68 to 70°N). The region presents dramatic alpine relief. The long-term evolution of the Norwegian margin results from the Caledonian orogeny followed by the Mesozoic rifting and offshore volcanism associated with the North-Atlantic oceanic breakup at c. 50-56 Ma. Bedrock samples were collected at sea-level and additional high-elevation samples were also collected to form elevation-profiles. The results were associated with available apatite fission-track data into inverse thermal modelling using QTQt. The dataset gives an unexpected insight on the extent and character of late Cenozoic erosion in North Scandinavia and the polar regions. A consistent set of AHe ages are younger than any published AFT or AHe ages at surface in Scandinavia (i.e. < 72 Ma). After a long period of tectonic exhumation derived from the Mesozoic rifting, the region underwent a long period with little erosion. Then, the dataset recorded a previously undetected phase of accelerated erosion since the Middle Miocene onwards. The results are interpreted as a consequence of efficient glacial processes, in the context of a gradual cooling of the North Atlantic, and point to Pre-Quaternary ice caps in northern Scandinavia, with a gradual ...