From landform inventories to landscape evolution? - Karst development in the Central Styrian Karst (Austria)

Abstract

In the Central Styrian Karst (CSK, Styria, Austria) 1158 karst landforms were used to obtain a better understanding of the landscape evolution in this region. An automatically delineated doline inventory was combined with an existing cave inventory to investigate surface and subsurface karst landforms in relation to their elevation above the local base level at the transition zone between the Eastern Alps and the Pannonian Basin. The landform entities analysed consist of 51 % dolines and 49 % caves and are related to various stages of landform evolution and thus ages. The CSK was ice-free during glacial times and therefore allow for a much longer preservation of surface landforms compared to landforms that were reshaped during glaciations. Nevertheless, weathering and downwasting do re-shape and even may lead to the disappearance of surface landforms (i.e., dolines); however, subsurface landforms (i.e., caves), if accessible, might preserve information about older geomorphological stages. An old, a mature, and a young stage of landform evolution can be distinguished in the CSK and be related to planation surfaces preserved in the area, presumably older than five Ma. The chosen approach is likely applicable for other areas in the world too by implying karstification over million years' time scale. Besides those regional implications, there are local (neo-) tectonic inferences derived from the analyses that might explain some discrepancies in correlations of levels and planation surfaces, but requiring further more detailed investigations. The automatic doline delineation in the forested karst of the CSK made an area not yet mentioned in the literature become apparent. With an increasing availability of high-resolution digital elevation models, remote-sensed inventories of dolines (surface landforms) renew the question of dolines as diagnostic landforms for karstification. However, in the CSK it is revealed that an absence of dolines due to e.g., surface erosion does not indicate the absence of karstification. Therefore, landscape evolution should consider both surface (i.e., doline) and subsurface (i.e., cave) landforms.

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