Séminaire de Philippe Steer (Bergen University)


 AHLeGall    03/02/2012 : 22:10

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Le vendredi 3 février à 11h00, en salle Bernard Auvray (Géosciences, RDC du bât 15, campus de Beaulieu), Philippe Steer propose un séminaire intitulé

Le vendredi 3 février à 11h00, en salle Bernard Auvray (Géosciences, RDC du bât 15, campus de Beaulieu), Philippe Steer propose un séminaire intitulé

Recent glacial erosion of fjords and low-relief surfaces in western Scandinavia

Philippe Steer est chercheur à l'université de Bergen (Norvège)


Présentation :
Although glacial landscapes are characterized by dramatic local relief, they also ubiquitously exhibit high-elevation low-relief surfaces. While these surfaces have been attributed to glacial headward erosion in Alpine settings, the timing and processes responsible for their formation in northern high-latitude regions remain elusive. Here, we investigate the topographic evolution of western Scandinavia during the Late Pliocene and Quaternary glaciations (0-2.8 Myr) by comparing inland erosion and offshore sedimentation. Fjord erosion over the entire western Scandinavia, quantified using the geophysical relief, only accounts for 30-55 % of the total sediment volume deposited offshore Norway. This large mismatch implies that significant erosion must have taken place at high elevation during this period, despite the conspicuous nature of the fjords. Furthermore, comparing the distribution of the low-relief surfaces with Equilibrium Line Altitudes (ELAs) suggests a glacial “buzzsaw” mechanism for their formation. In turn, by reconciling glacial erosion of fjords and topography around/above the ELA, our results clearly illustrate how glacial erosion can simultaneously increase topographic relief and still limit mountain height. We suggest that similar processes may have created similar morphologies in other northern high-latitude landscapes, and that models of their tectono-morphologic evolution should thus be reappraised.


Contact : Philippe Steer (Bergen University)

Contact OSUR : Dimitri Lague (Géosciences)