Late Cretaceous thick-skinned basement thrusting and associated thin-skinned fold-thrust-belt evolution in a plate’s interior – an example from Gardelegen-Haldensleben Basement Thrust System

Fold-and-thrust belts and foreland basin deformation are typically associated to orogenic systems along plate margins, where contraction and shortening is transferred to the foreland. In contrast the Late Cretaceous “hercynian” intraplate contraction affected large areas of the Central European lithosphere far away from the next adjacent plate margins. Shortening resulted in the inversion of basins and (half-)grabens, but also the formation of large basement-cored uplifts and crustal-scale thrusts occurred. Due to crustal scale thrusting and lithospheric folding foreland basins developed, which resemble structures typically known from foreland fold-and-thrust belts all over the world.

This contribution deals with the Gardelegen-Haldensleben Basement Thrust System in Central Germany. In this region two major basement thrusts formed and syntectonic sedimentary basins evolved in their northern foreland. Due to the existence of mechanically weak strata these foreland basins were deformed in parts by thin-skinned “fold-and-thrust belt style”. To unravel the evolution of thick-skinned and thin-skinned thrusts we used classical cross-section balancing methods of equal bed-length and areas, in parts supported by recently reprocessed seismic reflection data. Timing constraints and estimates of uplift and shortening were deviated from the correlation of boreholes, which penetrated the pre- and syntectonic strata.

Our results show that synchronously with thrusting wide areas in the foreland of the Gardelegen-Haldensleben Basement Thrust System were still affected by subsidence of the North German Basin, superimposed by foreland basin formation and successively growth and tilted Late Cretaceous strata. With the onset of Latest Cretaceous (Maastrichtian), uplift ceased and basin fill overlap earlier basement structures.