Critical taper behaviour and out‐of‐sequence thrusting on orogenic wedges – an example of the Eastern Alpine Molasse Basin |
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| Authors: | Volker Schuller Wolfgang Frisch Ulrich Herzog |
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| Affiliation: | 1. OMV Exploration and Production, Vienna, Austria;2. Department of Geosciences, University of Tuebingen, Tübingen, Germany |
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| Abstract: | We demonstrate that increasing erosion during the kinematic evolution of a thrust wedge will lead to out‐of‐sequence thrusting as a result of backwards critical taper movement. In‐sequence thrusting in the Subalpine German Molasse Basin built a critical‐tapered foreland Coulomb thrust wedge. Later, out‐of‐sequence thrusts dissected all but the frontal duplex stacks. The footwall/hangingwall relation visible on seismic data proves the out‐of‐sequence nature of the latest thrusting stage. Establishing a stable drainage system leads to increased erosion in elevated areas of the thrust wedge, resulting in flattening of the critical wedge. In order to keep its predefined angle, the critical wedge repositions and the tip of the taper moves towards the hinterland. Thus, thrusting will also reposition and move towards the hinterland. |
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