The polar research group of the Laboratory of Physical and Environmental Geography of Clermont-Ferrand (GEOLAB – UMR 6042-CNRS) carried out several activities of interest to the periglacial community. Following the SEDIFLUX International Meeting Shifting Lands held in Clermont-Ferrand in 2005 (see Frozen Ground 29), two special issues of Geomorphology and Géomorphologie were coordinated by Samuel Etienne and Denis Mercier.
Field surveys were conducted in Iceland and Svalbard. In North Iceland, Armelle Decaulne investigated slope processes and associated hazards in collaboration with Thorstein Saemundsson (Natural Research Centre of Northwestern Iceland, Saudarkrokur) with two objectives: (1) Quantification of the contribution of avalanches, debris flows and rockfalls to Postglacial development, with a special focus on the Late Holocene fan development; (2) Development of a predictive tool based on the longest runout distances of snow avalanche transported boulders. This approach, which uses the geomorphic evidences in the distal part of remote slopes and transfers the results to inhabited areas, can be considered as a complementary decision tool in hazard assessment. In Northwest Spitsbergen, Myrtille Moreau explored the relationships between glacial retreat, run-off processes and vegetal colonization, in collaboration with Thierry Brossard (THEMA, Besançon) and Dominique Laffly (Pau Univ.). This research project is based on the comparison of two sets of data collected in 1977 and 2006, in various environments (moraines, glaciofluvial deposits, marine terraces). In Svalbard, cooperation is developed between the French Polar Institute Paul-Emile Victor (IPEV) and the German Alfred Wegener Institute (AWI).
The Loven-FLOWS project (2006-2010), endorsed by the IPY Joint Committee, is an interdisciplinary and international project (France, Germany, Spain, Russia) led by Madeleine Griselin (UMR Théma, CNRS - Université de Franche-Comté) and Christelle Marlin (UMR IDES, CNRS - Université Paris-sud XI). The project focuses on the study of the hydrology of a polar glacier of western Spitsbergen (Austre Lovénbreen Glacier), subjected to large ice-retreat at least for the last four decades. Remote sensing data, aerial photographs, meteorological data and hydro- geochemical data will provide information for quantifying the Austre Lovénbreen Glacier reactivity to climatic variations. Two expeditions took place in 2006, one in April and the second in September to set up automatic equipment in the studied area (network of automatic digital cameras stations, hydrological and geochemical sensors and automatic meteorological stations). These data will be used in conjunction with remote sensing. The database (in collaboration with Spain for hydrology) will allow a global approach of spatial and temporal dynamics of the Austre Loven River system. In collaboration with geophysicists of the Alfred Wegener Institute, mapping of the permafrost and of the subglacial river network will take place as well as studies of the littoral progradation (Oceanographic Institute of Moscow) and of the marine sedimentology (Polar Ecology Institute of Kiel).
The periglacial group of the University of Caen (UMR CNRS 6143) investigates the effects of climate warming on periglacial slopes. Physical modelling experiments are carried out in a cold room to analyse the erosion processes and the morphological evolution of experimental slopes that accompanies thawing of the permafrost (J.L. Lagarde, M. Font, J.P. Lautridou and E. Vedié). Results from physical modelling will be compared to field data relative to Holocene warming in Western Europe that is characterised by a large scale thawing of the permafrost acquired during the peak of the last glaciation (Wechselian). A new methodology using Particle Image Velocimetry was developed. It provides an accurate understanding of the soil behaviour throughout catastrophic events such as debris flows. This application will also be applied to the physical modelling of Martian gullies (coll. F. Costard, UMR CNRS 8148). The programme «Laboratory simulation of solifluction processes associated with one-sided and two-sided active layer freezing» from the Cardiff group lead by Charles Harris is going on (see U.K. report). Results from the first year of experimental freeze/ thaw cycles in a cold room fits nicely with field measurements from Svalbard.
An on-going study of the consequences of climate warming on thermal and mechanical fluvial erosion is being conducted in the Lena River (Yakutia) by François Costard (UMR IDES, CNRS-Université Paris-sud XI) with Emmanuèle Gautier and Daniel Brunstein (Laboratoire de Géographie Physique CNRS UMR 8591). This study is expected to allow a quantitative analysis of the thermal and mechanical erosion: the bank retreat of the Lena River will be measured on the basis of aerial and satellite images (1960-2005) and all data integrated in a GIS. A field study was performed in the Lena River in September 2006 in collaboration with A. Fedorov from the Permafrost Institute (Yakutsk). Various samples were collected on sites with high erosion rates.
François Costard ([email protected])