Palaeosurfaces and major valleys in the area of the Kjølen Mountains, southern Norway - consequences of uplift and climatic change.

The undulating high plateaus of southern Norway, referred to as the Palaeic relief, are clearly distinct from the deeply incised valleys. The Palaeic relief has been regarded as either one or several surfaces, originating from differential weathering and pedimentation in warm climates or developed by fluvial cycles in response to changed base levels. Four major levels have recently been identified from a summit envelope surface. High-resolution elevation data from the Kjølen Mountains area, characterized by limited glacial erosion, were analysed to describe the relief. A surface/slope map showed three distinct surfaces with low inclination separated by slopes steeper than 6.5°. The stepped surfaces cut across different rock types. Their regular appearance in height along the main valleys, Gudbrandsdalen and Vågå-Otta valley, suggests a fluvial origin in response to successive uplift events. The main valleys are incised 300-600 m below the lowest Palaeic surface. Wide V-shaped tributary valleys, and valley benches preserved in resistant bedrock in Gudbrandsdalen, are indicative of fluvial incision, which can be correlated with Neogene uplift. A wide V-shaped valley was used as reference for estimation of the glacial erosion. A glacial deepening of the main valleys of 100-300 m and a widening of up to 1500 m was calculated. [ABSTRACT FROM AUTHOR]