Zechstein Group

Code
ZE
Status
Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1994).
Lithological description

Succession consisting of evaporites and carbonates with some thin intercalations of claystone. The evaporites consist of anhydrite, rock salt and minor amounts of bitter salts, and are locally strongly affected by halokinetic movements. Towards the southern edge of the Southern Permian Basin, siliciclastics gradually replace the evaporites and, to a lesser degree, the carbonates.

Depositional setting

Deposition of the Zechstein Group took place in a peri-marine to marine setting. During deposition of the Zechstein Group the basin became increasingly shallow. In the Z1 (Werra) and Z2 (Stassfurt) Formations the depositional setting varied from a lagoon to sabkha/mudflat at the margins of the basin, to deep marine in the centre of the basin. The clastics in the western offshore were deposited in an estuarine setting. The topography of the Southern Permian Basin was filled-in for the greater part by Z2 Salt. The Z3 (Leine) Formation was probably deposited in a shallow marine-environment. The higher cycles show decreasing marine influence in the basin; no carbonates are present and the claystone/halite alternations are more typical of a playa lake depositional setting. Minor extensional fault movements occurred during the lower (Z1) and upper Zechstein (Geluk, 1999; 2005; Geluk et al., 1997).

Definition of lower boundary

Taken at the base of the Coppershale Member in the Southern Permian Basin. This boundary has been chosen despite the fact that the uppermost part of the Upper Rotliegend Group may in part be genetically related to the initial Zechstein transgression (reworked sandstones and conglomerates). In the platform area in the southern Netherlands, younger strata of the Zechstein Group onlap the sediments of the Upper Rotliegend Group (e.g. Buurmalsen-1, Everdingen-1, Nederweert-1).

Definition of upper boundary

Placed at the base of the Lower Germanic Trias Group, which forms a well-recognisable marker on wire line logs. It marks a minor hiatus, reflecting the transition from the laterally variable nature of the Zechstein deposits into the regionally well-correlatable Lower Triassic sediments. Where erosion or halokinesis occurred, much younger units may overlie the Zechstein Group.

Thickness indication
Depositional thickness shows large variations - from less than 100 m in marginal settings to over 1200 m in the salt basin.
Geographical distribution
Regional correlation
UK: Zechstein Group; GER: Zechstein Group; BEL: Zechstein Group.
Age
Lopingian.
Holostratotype
Depth (thickness) AH:
1212 - 1804 m (592 m)
Hypostratotype
Depth (thickness) AH:
4378 - 4620 m (242 m)
Hypostratotype
Depth (thickness) AH:
3817 - 3872.5 m (55.5 m)
Hypostratotype
Depth (thickness) AH:
1973 - 2069 m (96 m)
Hypostratotype
Depth (thickness) AH:
2572 - 2634 m (62 m)
Origin of name
Name derived from the German stratigraphic nomenclature, where it is applied to the marine evaporite/carbonate sequence between the Rotliegend and the Triassic deposits. Zeche in German means mine gallery .
Previous name(s)
None.
Reviewed by (date)
Mark Geluk (2017).
References
Geluk, M.C. 1999. Late Permian (Zechstein) rifting in the Netherlands - models and implications for petroleum geology. Petroleum Geoscience 5, 189-199.
Geluk, M.C. 2005. Stratigraphy and tectonics of Permo-Triassic basins in the Netherlands and surrounding areas. PhD Thesis, Utrecht University, 171 p.
Geluk, M.C., Van Wees, J.D., Grönloh, H., Van Adrichem Boogaert, A.B. 1997. Palaeogeography and paleotectonics of the Zechstein Group (Upper Permian) in the Netherlands. Proceedings of the XIII International Congress on the Carboniferous and Permian, 28th August-2nd September 1995, Krakow, Poland. Prace Panstwowego Instytut Geologicznego CLVII, part 2, 63-75.
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1994. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section D, Permian. Mededelingen Rijks Geologische Dienst, 50, 1-42.
Cite as
TNO-GDN ([YEAR]). Zechstein Group. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/zechstein-group.