| The goal of this thesis is to reconstitute the initiation and the development of syngenetic ice-wedge polygons located on Bylot Island, in the Canadian Arctic archipelago. During the Late Holocene, the initial configuration of the polygonal network has been modified by a change in the rheological properties of the ground linked to the accumulation of loess and organic sediments after 3670 +/- 110 BP. Significant changes of the surface wind regime and precipitation-evaporation regime of the polygons occurred during the last 3500 years, likely in response to changes of the atmospheric circulation and of the position of the "Canadian Polar Trough". Frost-cracking of the ground is the geomorphological process responsible for the development of the ice wedges whereas the fluvial thermo-erosion and thermokarst processes lead to the destruction of the polygons. |
