Paraglacial gullying of sediment‐mantled slopes: a case study of Colletthøgda,Kongsfjorden area,West Spitsbergen (Svalbard) |
| |
| Authors: | Denis Mercier Samuel Étienne Dominique Sellier Marie‐Françoise André |
| |
| Institution: | 1. Université de Nantes, Laboratoire Géolittomer, CNRS – UMR 6554, Campus du Tertre, BP 81 227, F‐44312 Nantes cedex 03, France;2. CNRS – GDR 3062 ?Mutations polaires?;3. Université de la Polynésie fran?aise, BP 6570, F‐98702 Faa'a, Tahiti, French Polynesia;4. Clermont Université, ‘Laboratoire de géographie physique et environnementale’ GEOLAB, CNRS – UMR 6042 / Université Blaise Pascal, Maison des Sciences de l'Homme, 4 rue Ledru, F‐63?057 Clermont‐Ferrand cedex, France |
| |
| Abstract: | This paper evaluates the paraglacial evolution of a sediment‐mantled slope in a polar maritime environment. The intensity of paraglacial processes is estimated through quantification of erosion and dating of field sectors with the help of photographic archives. Gully erosion has been estimated using morphometric parameters and by surveys of vegetation cover. The rapid melting of dead‐ice cores controls gully formation. This leads to slope form modification: gully profile gradients are reduced from a mean of 35° to a mean ranging between 10° and 15°. Profile evolution results from the collapse of glacier lateral moraine. All data (mean slope angle of individual gullies, frequency distribution of slope angles, fractional distance to the apex, gullying index, volume of debris mobilized, vertical erosion rate) tend to increase with increasing deglaciation age and the duration of paraglacial activity. Vegetation colonization is a response to stabilization of the ground surface and the drying up of the ground surface due to dead‐ice melting. The full sequence of paraglacial slope adjustment (gully incision‐stabilization) may occur rapidly at the study site, i.e. within two decades. Finally, a lateral morphogenic sequence is proposed showing the importance of paraglacial processes at the onset of the deglaciation. Copyright © 2009 John Wiley & Sons, Ltd. |
| |
| Keywords: | paraglacial geomorphology timescale slope processes glacial environment Spitsbergen |
|
|
