Abstract A detailed analysis of the Late Miocene Mandach Thrust, a key tectonic structure of the easternmost Jura Mountains (northern Alpine foreland), is presented providing insights into the modes of along-strike structural cover–basement interactions in a classical foreland setting. Our study builds on the construction, restoration and forward modelling of eight closely spaced cross-sections constrained by depth-migrated 2D seismics and geological maps. The results indicate predominantly thin-skinned thrust tectonics without significant inversion of underlying basement structures. However, inherited pre-thrusting normal faults exerted a strong control on the observed thrusting style, changing along-strike from a comparatively simple geometry to a complex, partly overthrust, partly reactivated normal fault. The observed variations relate to changes in the relief of the mechanical basement and the characteristics of pre-thrusting normal faults. The thrust's complexity is further increased by the local activation of secondary detachment horizons and possibly along-strike sedimentary facies changes within the thrust-faulted sedimentary sequence. The variations in thrusting style go along with subtle changes in shortening that may point towards as yet undetected transfer structures. As such, our structural analysis of the Mandach Thrust provides an improved understanding of the fault's kinematics and serves to highlight existing exploration uncertainties.

Abstract Mesozoic extensional basins of the Southern Permian Basin (SPB) System became inverted from Late Cretaceous time onwards. Following a first Cretaceous ‘Subhercynian’ pulse of contractional deformation and basin uplift, several distinct inversion events of Cenozoic age were often described. The oldest of these is the ‘Laramide’ event of Paleocene age which coincides with the termination of chalk deposition and widespread regression around the North Sea Basin, whose axial part continued to subside. The spatial extent of these effects is too wide to be compatible with inversion by folding and reverse faulting. The width of the uplifting and subsiding regions was also too large to be consistent with folding of the entire lithosphere under tangential compression. There appears to be no unequivocal evidence of discrete structures formed or reactivated in the Laramide event. By contrast, well-documented younger inversion of approximately Late Eocene to Late Oligocene–(Miocene?) age affected the region from the Celtic Sea to the western Netherlands. The associated deformation is weaker than that of the Late Cretaceous event and spatially overlaps with it only in the Southern North Sea. Structural inversion of the SPB thus comprised only two events separated in time and mostly also in space.

Abstract The northern front of the Cenozoic Tien Shan mountains in Kazakhstan comprises east- to NE-trending thrust-related basement uplifts. Some of these are open, asymmetric anticlines, whereas others are fault-bounded blocks. Where emergent and exposed, the bounding faults dip steeply at 45–70°. Large-wavelength open folds in the Cenozoic cover also overlie basement structures. The Palaeozoic basement of volcanic, (meta-) sedimentary and granitic rocks contains older structures such as folds, slaty cleavage, faults and dykes. Some Cenozoic faults truncate all earlier structures, just as some Cenozoic folds are independent of the attitudes of underlying stratified basement rocks. The strongest control on the Cenozoic structure is exerted by steep, NW-striking basement faults that induce along-strike segmentation and lateral terminations of some basement ridges. A few of these basement faults had already been reactivated as normal faults during a Cenozoic phase of east–west extension that preceded folding and thrusting. Some normal faults show reactivation as dextral strike-slip faults during the contractional phase, which is still active today. Since the NE to east trend of the main basement ranges has no obvious precursor structures, we interpret the thick-skinned structures to essentially reflect the modern shortening direction, modulated but not dominated by pre-existing basement faults. Variations in local kinematics over time are probably due to strain partitioning in the anisotropic basement, not to changing far-field stresses. The occurrence of steep dip-slip reverse faults apparently unrelated to reactivation presents an unsolved mechanical paradox similar to some low-angle normal faults.