POT CASTS IN THE UPPER MUSCHELKALK (MIDDLE TRIASSIC) OF WEIMAR/THURINGIA - COMPOSITION, MICROFABRICS AND DIAGENESIS

A horizon with pot casts (potholes) is described from shallow-marine limestones of the spinosus-zone ('Discitesschichten', Upper Muschelkalk) near Weimar/Thuringia. The erosional structures are not developed as sole marks but occur as isolated structures. They differ distinctly in size and composition from pot casts described from the Muschelkalk of Southern Germany. Vertical sedimentary zonation and varying sediment infill in the structures suggest continuous erosion and deposition contemporaneous with the background sedimentation. Deposition may have been caused by oscillatory and unidirectional flows as well as a long period of micrite deposition. Early diagenetic deformations (e.g. dewatering, brecciation, pressure solution) have controlled by a higher continuous water flux inside the pot casts and higher intergranular dispersal pressure.