The Impact of Lithology on Fjord Morphology

• Published in: Geophysical Research Letters
• Main Authors: Bernard, Mathieu, Steer, Philippe, Gallagher, Kerry, Egholm, D., L
• Other Authors: Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Aarhus University Aarhus, University of Aarhus, Denmark French Institute, Université de Rennes 1, European Project: FEASIBLe
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Greenland; Ice Sheet
• Online Access: https://insu.hal.science/insu-03320558; https://insu.hal.science/insu-03320558/document; https://insu.hal.science/insu-03320558/file/2021GL093101.pdf; https://doi.org/10.1029/2021GL093101

International audience Assessing the impact of glaciations on topography and the co-evolution of ice-sheet dynamics requires a thorough understanding of the factors that control fjord morphology. We investigate the role of lithology on glacial valley form using topographic analyses and numerical landscape evolution models. We measure fjord depths and widths from East Central Greenland (68°N–75°N), and find a control of lithology on fjord width, with wider fjords in softer rocks (i.e., sedimentary rocks). This dependency of fjord width to bedrock properties is predicted by a quarrying erosion law, but not by an abrasion one, when considering results from a simple two-dimensional model and a more detailed three-dimensional ice flow model (iSOSIA). Our analyses and numerical results reveal a potential control of lithology on the width of glacial valleys with glacial quarrying as a plausible responsible mechanism.