Ice Wedge Polygon

Abstract

DefinitionThe surface expression of permafrost crosscut by integrated/intersecting polygonized fractures (formed by means of thermal-contraction) that are filled with frozen water, i.e., ice wedges.CategoryA type of nonsorted patterned groundA type of periglacial landformMorphometryIce-wedge polygon networks range from a few meters to tens of kilometers in reach (Fig. 1) (Washburn 1973; Mackay 1980; French 2007). Typically, individual ice-wedge polygons show diameters in the 5–40 m range (Washburn 1973; French 2007); however, ice-wedge polygons with diameters >100 m have been observed in Eastern Siberia (Geocryology of the USSR, Eastern Siberia and the far east 1989). Ice-wedge diameters at the apex range from <10 cm to >3 m, commonly tapering to a feather edge at a depth of 1 to >10 m (Harris et al. 1988).Fig. 1An extensive outcrop of thermal-contraction polygons (~15–25 m in diameter) in the Tuktoyaktuk Coastlands (Photo by R. Soare)SubtypesSee