Bochumer geologische und geotchnische. Heft 49 (1998). Der bentheimer sandstein (Valangin, NW-Deutschland). Eine palokologische und sequenzstratigraphische analyse

This thesis represents one part of the European project “Geological characterisation of shallow marine sands for reservoir modelling and high resolution stratigraphic analysis”, which was established to study shallow marine sands with respect to reservoir properties. The research was focused on the micropalaeontological characterisation of mudstone and source rock successions and the nature, origin and reservoir characteristics of the Bentheim Sandstone in the Lower Saxony Basin.

Samples were collected from outcrops around the town of Bentheim and from cores drilled in the Emsland oil province, both areas are situated in the westernmost part of the Lower Saxony Basin. According to micropalaeontological data, depositon of the Bentheim Sandstone have occured from the upper part of the Lower Valanginian to the lowermost Upper Valanginian. Palaeoecolgical and palaeobathymetric studies have shown that the sandstone was shallow marine in origin and was deposited during regressive- transgressive cycles.

This thesis, for the first time, interprets the Bentheim Sandstone in term of sequence stratigraphy. Due to sedimetological findings, the Sandstone could be subdivided into three sandstone-dominated genetic sequences. These three regressive-transgressive cycles form a retrogradationally stacked set. Sequence 1 is interpreted as a tectonically enhanced valley systems filled with estuarine deposits. Sequences 2 and 3 are tidal shelf sand bodies deposited in progressively deeper water. As a conclusion a new depositional model for the Bentheim Sandstone is presented.