Cutting samples of 23 geological formations from different depths (measured depth, MD) between 1.4 and 4.4 km of the geothermal research well Groß Schönebeck site were analyzed with focus on lithium (Li), copper (Cu), and strontium (Sr).

To determine how strong and to which components these critical raw materials (CRM) are bound within the rocks, leaching and sequential extraction experiments were performed on five selected formation rock samples that are considered either for geothermal exploitation (Muschelkalk, Buntsandstein, Rotliegend sandstone) and/or as potential source for the CRM Li, Cu, Sr from the Permo-Carboniferous volcanic rocks and/or the Ohre anhydrite. In addition, electron probe micro analyses (EPMA) and laser ablation ICP-OES was performed on thin sections of the Rotliegend formation.