Topographic evolution of the Eastern Alps: The influence of strike-slip faulting activity

Abstract

We present the results of a numerical model that was used to investigate aspects of the landscape evolution of the Eastern European Alps in the Miocene. The model allows the consideration of strike-slip faulting, an inherent feature of the Miocene tectonics in the Eastern Alps, within a viscous medium. Mechanical deformation of this medium is coupled with a landscape evolution model to describe surface processes. For the input variables, the activity history of strike-slip faulting in the Eastern Alps was compiled from literature sources. The results present a major improvement in the predicted topographic development over earlier models in terms of the location and build-up of valleys and mountain ranges that form in response to the strike-slip faulting activity. Intramontane basin formation is predicted and the metamorphic dome of the Tauern Window evolves dynamically in the simulations, related to well-known east-west–striking strike-slip faults in the region. It is interesting that the metamorphic dome formation is predicted by the model without explicit consideration of the low-angle detachments bounding the dome in the west and east, suggesting that metamorphic domes can form in transpressional or strike-slip environments. The model underpredicts the mean elevation of the Eastern Alps by several hundreds of meters, which is interpreted in terms of an independent non-convergence-related event of the past 5 m.y. that has been inferred previously from other field data. Time-series analysis of elevations reveals a clear correlation between maximum height and the amount of strike-slip activity and a nonequilibrium state between uplift and erosion. We interpret this in terms of future topographical growth of the Eastern Alps.