Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

Figure 1

Dedolomitization model of the Zechstein-2-Carbonates as defined by Clark [9] (depositional model after Strohmenger et al. [1]). Dehydration of the over- and underlying gypsum deposits led to the large scale release and migration of calcium-rich fluids, as indicated by the black straight arrows. The CO₂ which is needed to bring dolomite into solution is produced during organic matter maturation which primarily took place in the lower slope to basin facies. High amounts of CO₂ lead to higher degrees of dedolomitization, explaining why basin to slope deposits show a higher degree of dedolomitization while the platform deposits are largely dolomitic. Pie charts displaying the distribution of calcite and dolomite for different depositional environments are chosen from representative wells within the study area.