Plio-/Pleistocene landscape evolution in the Eastern Alps: new insights from cosmogenic nuclide dating

The Eastern Alps hold an abundance of landscapes with noticeably low topographic gradients at higher elevations above much steeper slopes. Many of these elevated low-relief landscapes (ELRL) are organized in distinct surface levels. Sub-horizontal cave systems can often be found at similar elevations. Utilizing spatial statistics of these ELRL and over 15000 caves, we show that the formation of both the surface and sub-surface landscapes is connected and can help deciphering the landscape evolution of the Eastern Alps from the Late Neogene until today. New cosmogenic nuclide data (¹⁰Be, ²¹Ne, ²⁶Al) of allogenic quartzous sediments from caves and surfaces of distinct elevation levels in the Eastern Alps are used to quantify the incision and ultimately surface uplift history. Burial ages of cave sediments scatter between 0.5 and over 5 Ma. The preliminary data indicate a mean surface uplift of some 0.15 – 0.25 mm/year for much of the Pliocene. We also show that most ELRL in the Eastern Alps can be interpreted in terms of pre-Pleistocene relict landscapes, especially in the only minorly glaciated eastern part.  However, the data also show some impact of the Pleistocene glacial cycles on the ELRL and the mobilization of sediments associated with them.