Basin inversion in tectonic wedges: Insights from analogue modelling and the Alpine-Carpathian fold-and-thrust belt

Abstract

This work simulates the inversion and incorporation of sub-thrust segmented half-graben basins into tectonic wedges by means of sandbox analogue models. Segmented half-graben basins - striking at 90°, 45° and 15° to the extension direction - were created first, and then shortened using different angles for the basal detachment and topographic slope. A shallow viscous polymer layer located above the half-graben basin was included in one of the models. The experiments were analysed using time-lapse photography, topography laser scans and image-based 3D voxels. The results indicate a deformation sequence characterised by layer-parallel compaction, fault reactivation, thrust propagation and related folding. Fault reactivation was associated with the layer-parallel compaction accomplished by slip along the basal detachment, prior to and in between pulses of thrusting. Results reveal the fundamental control imposed by the vertical load of the tectonic wedge and its integrated strength profile in the inversion of sub-thrust basins. Results are compared to the Alpine-Carpathian fold-and-thrust belt.