Salt in the North German Basin and Its Role in Mesozoic Deformation

Magdalena Scheck-Wenderoth, Yuriy Maystrenko, Ulf Bayer, and Björn Lewerenz
GeoForschungsZentrum Potsdam, Potsdam, Germany

The North German Basin (NGB) contains up to 12 km of Permian to Cenozoic deposits. Initiated as a part of the Southern Permian Basin, the NGB accumulated Lower Permain clastics overlain by Upper Permian Zechstein salt. Mesozoic differentiation of the basin was controlled by variable regional stress conditions including Late Triassic extension, Mid-Late Jurassic uplift, Early Cretaceous transtension and Late Cretaceous –Early Paleocene compression. These tectonic phases not only provoked regional shifts in subsidence and uplift but also triggered the mobilisation of the Zechstein salt which strongly influenced the Mesozoic structural evolution in terms of mechanical decoupling of the cover from its basement. Consequently, the NGB displays a wide variety of salt structures with structural amplitudes of up to 8 km. This makes it a classical site to study the interaction of salt rise, deposition and tectonics. We use a combined approach of subsidence analysis and seismic interpretation to unravel the mechanisms controlling basin evolution and the related salt pathways. Subsidence analysis includes 3D backstripping with salt redistribution in response to the changing load conditions in the salt cover.

On the basin scale, two main families of salt structures can be distinguished: (1) In the central part of the basin, salt structures with NNE-SSW striking axes border Triassic-Jurassic graben structures of identical orientation and are genetically linked to the latter. (2) The evolution of salt structures aligned along NW-SE striking axes close to the southern basin margin is related to Cretaceous transtension followed by compressive inversion.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005