ABSTRACT
Little is known of active glacierized continental karst; the closest analogues are in Spitsbergen (Svalbard) where karst springs emerge from below small ice sheets. Continental ice sheets are mobilized by their own topography rather than that of the buried landscape. The directions of ice flow and hydraulic gradient may bear little relationship to ground topography, being controlled largely by the ice surface slope. The flow in icesheets appears to have been focused in fast-moving ice streams that can cut deep glacial valleys, and construct enormous moraine complexes. At the frozen margins of icesheets, particularly steep hydraulic gradients arise from the steep glacier slope, and the accumulated meltwater derived from up-glacier. Groundwater may be driven through deep karst formations, destabilizing overlying beds and even erupting through spontaneous vertical shafts. The Earth’s crust deforms under glacial loading and unloading leading to relatively short-term changes in base level and possibly inducing deep groundwater circulation impossible under static conditions. Similarly, water sequestered in glaciers causes significant falls in sea level (up to 130 m during the last glaciation), allowing drainage of karst aquifers, and formation of speleothems well below current sea level.
