Summary

The sulfatic member of the Upper Permian Zechstein 1 Cycle (Z1), the Werra Anhydrite (A1), is, due to excellent preservation, a very good example of an ancient sulfate depositional system to be studied in terms of evaporite facies distribution and sequence stratigraphy.

Four main facies types, (I) supratidal, (II) intertidal, (III) shallow subtidal, and (IV) deeper marine, are further subdivided into 10 subfacies types which are (1) karst and (2) sabkha within the supratidal environments, (3) algal tidal-flat, (4) tidal flat, and (5) transgressive deposit within the intertidal main facies type, (6) salina, and (7) sulfatic arenites within the shallow subtidal environment. Subfacies types of the (8) slope commonly associated with (9) turbidites and the (10) basin subfacies type subdividing the deeper marine depositional environment.

Vertical stacking patterns of these facies and subfacies types reveal the sequence stratigraphic development of the sulfatic system in response to sea-level fluctuations. The Werra Anhydrite is built up of the A1-trangressive systems tract (1 parasequence), the A1-highstand systems tract (3 parasequences), and the A1-lowstand systems tract (1 parasequence). The 5 parasequences are 4th-order cycles, each of which represents about 100,000 years of deposition.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah