Main Buntsandstein Subgroup

Alternating succession of often anhydritic, grey to reddish-brown sandstones and silty claystones, containing occasionally some intercalated oolitic limestone beds.

Fluvial influence repeatedly extended far into the basin, alternating with intermittent rises in water-level in the basin. Wind-blown deposits occur locally.

Placed at the base of the lowermost thick sandstone bed.

As a result of differential erosion below the Hardegsen Unconformity, each formation of the Main Buntsandstein Subgroup may be unconformably overlain by the Solling Formation. Along the basin margin, where sandy sediments prevail, it may be difficult to distinguish the boundaries between the formations in the Main Buntsandstein Subgroup, and to discern the base of the overlying Solling Formation. This is particularly true for well sections that are studied in isolation. ln such cases it is possible to lump the formations (Volpriehausen, Detfurth and Hardegsen) together with the Basal Solling Sandstone Member into the informal middle Bunter sandstone (RBBM).