The lower parts of the evaporite cycles of the Zechstein Formation within the North German Basin comprise large deposits of several 10 to 100 meters thick sulphates, intercalated with carbonate, dolomite and clay. These sulphates were deposited in the deeper parts of the basin as gypsum that underwent dehydration and compression, forming anhydrite. Also, several thin anhydrite / gypsum layers divide the thick salt deposits of the Zechstein Formation. In these stratigraphic successions of anhydrite, the deposits are often highly textured and show a broad spectrum of structures ranging from pseudomorph crystals to nodular or even layered shapes.
The precipitation of evaporates follows the solubility, resulting in the evaporitic sequence.The dissolution and recrystallisation of evaporite deposits are complex processes that are influenced by several parameters such as temperature, pressure and water availability. Therefore, at low temperatures the anhydrite deposits are supposed to be more stable than other evaporites making them a possible paleo-archive of sedimentary and diagenetic conditions. Furthermore, they can be used to infer halokinetic and halotectonic processes of evaporites.
In this study, we analyse the variation of textures, including laminated, nodular, pearl-like successions within anhydrite deposits of drilling cores and local outcrops. Based on the observation, we suggest evidence for primary and secondary processes occurring during the deposition and diageneses within different regional and tectonic settings in the North German Basin. This study will provide a broader understanding of the rheological behaviour of sulphates, which is important for future subsurface planning efforts and karst development.