Mesozoic intraplate deformation in the southern part of the Central European Basin - Results from large-scale 3D modelling

Abstract

The Central European Basin is an intracontinental basin that initially formed due to long-lasting thermal subsidence accompanied with several tectonic phases of extension during Mesozoic times. Locally, thick evaporites were incorporated in the deformation and led to the formation of detached structures, salt pillows and diapirs. At the end of the Late Cretaceous, the formation of (sub-) basins and (half-) grabens became interrupted by a short-term event of contraction. Especially along the northern and southern edges of the basin, lithospheric shortening resulted in basin inversion and the uplift of large basement blocks. Hence, the present day's structural framework shows a complex pattern of kinematically and chronologically variable structures. Herein, we unravelled these structures for the Altmark region in northern Saxony-Anhalt (Central Germany). We used regional depth maps, reflection seismics and borehole data analysed by use of large-scale subsurface mapping and 3D modelling techniques to completely re-evaluate the structures in the Late Palaeozoic to Cenozoic sedimentary basin succession. Our results show a high variability of tectonic structures: narrow and distributed, in parts reactivated normal fault zones, huge inverted basins, thin-skinned thrust faults, detachment folds and large basement thrusts. The style of deformation significantly changed during the region's evolution. This is indicated by particular structural, kinematic, thermal and rheological conditions, which existed for the individual phases of basin formation and inversion and probably persist until today.