Geological history of the southern Horn Graben

Abstract

The structural history of the southern Horn Graben is analysed based on the data of the released German offshore wells Q-l, R-1 and S-1 and two E-W directed seismic lines. Rifting presumably already started during the Late Carboniferous. The main phase of taphrogenesis took placè during the deposition of the Lower and Middle Buntsandstein (Bacton interval) and an asymmetric graben with a more pronounced western flank was formed. During Röt and Muschelkalk sedimentation, Permian salts mobilized at the boundary faults and in the graben center, forming salt pillows. These salt structures entered the diapiric stage mainly during Keuper deposition while subsidence continued. At the beginning of the latest Jurassic and during the Early Cretaceous general subsidence and tilting towards the west took place, following a Middle-Late Jurassic period of uplift and erosion of the Graben and its surroundings. The negative movements have continued at incieasing rates till present times. Weak diapiric movements in the salt structures persisted until the Late Miocene.