EUROCORES_TopoEurope 1.Call_4D Kinematics of the Neogene Eastern Alps (TopoAlps)

This project aims to generate and compile tectonic data for the Eastern Alps for the Neogene to provide the tectonic template for the CRP Topo-Alps. Our project is directly complementary to the IP of Mancktelow (providing the tectonic template for the Central and Western Alps). The goal of this project is to identify the driving force for uplift and denudation in the Eastern Alps and contrast it with the processes operating in the West, by providing and interpreting a high resolution data set on both, the horizontal and the vertical kinematics of the orogen. Emphasis is split into two time slices of different scales: Firstly, the time covering much of the Neogene. Within this time slice, we will: (i) Collect and complement data on horizontal kinematics. This will involve synthetisation of available data verified by field checks of earlier sampling locations to detail the times of activities of all major fault zones. (ii) Collect and complement data on vertical kinematics. Data on uplift of different tectonic blocks will be compiled and somewhat complemented with new fission track data from two key areas: the Katschberg region and the Koralpe region. This task will be performed by the Postdoctoral fellow in cooperation with collaborator Fügenschuh. Secondly, we will study the much shorter time period of the Holocene. There, work will involve (i) Processing of geodetic levelling data in cooperation with collaborator Ruess at the Austrian surveying agency BEV. (ii) Morphometric mapping in the orogen - basin transition zone. This task will involve analysis of high resolution digital elevation models and morphological field data in the transition zone between Alpine orogen and Pannonian (Styrian) Basin. This task will be coordinated with similar studies of the IP of Schlunegger in the Central Alps. Cosmogenic isotope-derived erosion rate studies may be performed by the IP of Blankenburg in the same key areas were re-processing of levelling data and morphometric mapping is performed. The combination of this information will yield in a unique test if surface erosion relates to rock uplift, climate, or inherited basin properties. It will result in identification of the driving force for uplift and erosion and allow detection of locations, scales and importance of feedback mechanisms between environment and lithosphere.

The European Alps are one of the best studied mountain ranges on Earth. Interestingly, one of the most simple questions - the question about the age of the topography itself - is almost unknown. Even the relative stage of evolution is unclear: Are the Alps still growing, in a steady state or already decaying, and is there a significant difference between Western and Eastern Alps? Within the TOPOAlps project we have followed this question using different approaches:We used geochronological dating techniques to date rocks on the sides of major fault zones in order to understand the horizontal motions that the Alps have undergone in the last 30 million years. In particular we have investigated faults in the region of the Ennstal, the Lavanttal fault, the Katschberg region and other fault zones around the Tauern Window. We have also used geochronology together with numerical modelling techniques to refine our understanding of the uplift history of the Alps. Our results show that the morphological evolution of the Alps is in close connection with the geological evolution of the Dinarides and that of the Pannonian Basin. Uplift started in the Miocene but was not continuous: There is currently an new and ongoing uplift event that started only 4-5 million years ago. This result is confirmed by correlation with sediment budget data and with cosmogenic isotope dating results for cave formation ages (see: http://wegener.uni-graz.at and: http://www.alpengeologie.org ).In summary we could show that the range is still in its infancy: In contrast to several other mountain ranges, the Alps have still more than half of their evolution to a geomorphic steady state to go. Our results question the apparent consensus that the topographic evolution is distributed over much of the Miocene and might give new impulses to the reconstruction of paleoclimate in Central Europe.