News on the Geology of the Haltern Formation in Western Münsterland

The retaining formation of the upper chalk, which occurs in the western Münsterland region, consists essentially of fine and medium sands, which can sometimes also be coarsely sandy or weakly sloppy. In some cases, quarcitic sandstone banks, which are rarely hardened with limestone, occur. The distribution area of the Haltern Formation has an area of approximately 850 km². It reaches its largest widths at up to 300 m at Groß Reken and Holders. The regional structure of the area is characterised by wide, flat-wave chalk saddles and mullets. While the wrinkle structures in the western part of the distribution area are west-northwest — east-southeast, they turn in the eastern part into a southwest-north-east direction. The width distribution of the holder formation is significantly influenced by the course of these wrinkle structures. While the idea of relatively undisturbed layers was widespread for a long time, the research results described show the image of tectonically influenced layers. These are significant north-west — southeast-facing transverse disturbances of the carbon, which usually continue in the form of so-called reverse ejectors (late Cretan inversion) into the Cretaceous Deck Mountains.