Stream profile analysis of the Koralm Range (Eastern Alps)

Abstract

The Koralm Range at the eastern margin of the Eastern Alps shows an asymmetric topography. Steep slopes and short stream channels characterize the south-western segment, whereas gentle slopes and elongated catchments incise the mountain range towards the east. The fluvial landscape dissecting this mountain range is characterized by stream long profiles and by analyzing the power-law scaling between stream slope and drainage area. The concave-up form of the stream long profiles suggests an equilibrium state of the fluvial landscape. In accordance with a tectonic model describing the tilting of the Koralm Range as a consequence of a Miocene block rotation, slope-area data from stream channels suggest a spatial differential uplift pattern. A north-to-south-increase of the steepness values might indicate faster uplift rates in the central Koralm Range. This trend is traced by Paleogene low-temperature geochronological data and by the Late Cretaceous metamorphic field gradient. Thus, it may be explained by a long-term spatial pattern of exhumation and subsequent uplift which remained stable since the Late Cretaceous.