Group of formations, comprising conglomerates, claystones, sandstones predominantly of red-bed type and evaporites.
Deposited in the Southern Permian Basin. The centre of the basin was occupied with a large inland saline lake where predominantly clay was deposited and sub-ordinate amounts of evaporite sediments (halite) were formed. Towards the basin fringe, to a progessively more proximal position, the clay depositional domain transistionally changes to sand depositional domains and finally to a conglomeratic one. These depositional domains are roughly from distal to proximal: playa lake / salt pan, mudflats, sandflats, 'aeolian' sand seas fluvial & alluvial fans including wadi systems. On the basis of the widespread occurrence of aeolian and evaporitic sediments, in combination with their barren nature, these deposits are interpreted to have been formed in a desert-/playa-lake complex.
Unconformable contact (Saalian unconformity) with the Limburg Group (or locally the top of the volcanics of the Lower Rotliegend Group). The contact with the Limburg Group is generally characterized by a sudden shift in lithology, often combined with a downwards increase in compaction (due to pre-Saalian burial of the Carboniferous). Where thick sand bodies and red beds occur in the underlying Limburg Group, the boundary may be difficult to discern on wire-line logs. In cores, however, the difference in sedimentological character between Upper-Rotliegend and Limburg Group deposits is generally quite clear (Mijnlieff et al. 2011).
Contact with the Zechstein Group. In general this contact is formed by the base of the Coppershale Member or Fringe Coppershale Member of the Z1 (Werra) Formation, reflecting the extremely rapid Zechstein transgression. However, in the southern onshore area the top of the Upper Rotliegend Group can be formed by a disconformable contact with younger Zechstein Group claystones and/or carbonates.
