Influence of Pre-Existing Structures on Thrust Kinematics and Strain Partitioning at the Alpine-Carpathian Junction

Summary Interpretation of new 3D reflection seismic data from the Vienna Basin was integrated with surface geological data in order to study the kinematics of Cenozoic thrusting at the Alpine-Carpathian junction. The interpretation of these data sets reveals different directions of thrusting in two overlying tectonic units. This is shown for both, the in-sequence thrust deformation during Paleogene and Early Miocene sequential foreland-propagating thrusting and the Early Miocene out-of-sequence thrust deformation, which modifies the nappe architecture of both units. In this way thrusting is directed towards the N in the Rhenodanubic Flysch units and towards the NW in the Molasse thrust units in the footwall of the flysch. The contemporaneous activity of N-directed out-of-sequence thrusts in the flysch units and NW-directed in- and out-of-sequence thrusts in the Molasse thrust units during the Early Miocene suggests that strain partitioning occurs along the basal thrust of the flysch units. Early Miocene strain partitioning and local thrust directions are interpreted to be controlled by both, the geometry of the underlying Bohemian Spur and the initial nappe architecture of the Rhenodanubic Flysch units. The relevance of the resulting complex kinematic setting for hydrocarbon exploration and exploitation of thrust units below the Vienna Basin is highlighted.