Evidence of subglacial karstification in Glomdal, Svartisen, Norway

Abstract

The central Glomdal caves, Storbekkgrotta and Kalkrastgrotta, are found within a 30 m (approximately) thick band of white marble. The karst system is allogenic and the cave morphology and surface topography provide evidence of several phases of development: 1. Phreatic conduit development. 2. Drainage and vadose incision. 3. Partial or complete infill with clastic (glaciogenic) sediments. 4. Glacial truncation of the conduits. 5. Reversed, phreatic flow in the up-hill direction, producing paragenetic halftubes and rock pendants. 6. Partial outwash of the previous infilling sediment. 7. Holocene vadose invasion. Since the paragenetic features are superimposed onto vadose features, the reversed flow must have occurred after base-level (i.e. bedrock) lowering. Together with the topographical situation of the karst, phase 5 (paragenesis under reversed flow) may be explained by subglacial water flow. This implies a temperate glacier sole at a time when the icefield could over-ride the local valley topography a...