Permafrost mapping and prospecting in southern Norway

Abstract

Permafrost is formed in soils and rocks where mean annual ground surface temperature is maintained below O'C. For most practical purposes permafrost can be considered as impermeable, and the existence of permafrost will therefore influence runoff and near surface moisture content, which is critical to geomorphological processes such as frost sorting, frost heave, solifluction, debris flows and mass transport by fluvial processes. If permafrost is ice-rich, creep might occur in the permafrost. Rock glaciers are defined as the morphological expression of creep in perennially frozen, supersaturated sediments under the influence of gravity alone (Barsch 1978, Fisch et al. 1978, Haeberii 1978). The existence of permafrost also influences the thermal characteristics of the snow cover (Keller & Gubler 1993). This is important to snow meta- morphism and refreezing of meltwater in an ini- tially cold snowpack will delay the first runoff in early spring. Later in spring when the snow is mostly isothermal at 0°C, low infiltration characterizes permafrost areas and large spring floods occur if the discharge is not buffered by glaciers or large lakes