Z4 (Aller) Formation ZEZ4

 

Premise First described in the Netherlands by Visscher (1955) , it was formally introduced by NAM and RGD (1980) as the Z4 Formation. It has been renamed and slightly amended here.
Derivatio nominis Name derived from the German stratigraphic nomenclature, where it is used for the fourth evaporite cycle of the Zechstein Group Richter-Bernburg (1955) .
Type section Location map See figure (pdf)
  Well Rossum-Weerselo-3 (pdf)
  Location N 52°21’03.5
E 06°54’38.2
  Depth 1235 to 1245 m
  Length 10 m along hole
  Reference NAM and RGD (1980) .(sub-basin setting)
Additional section Location map See figure (pdf)
  Well Drouwenerveen-Zuideind-1 (pdf)
  Location N 53°57’41.7
E 06°52’16.9
  Depth 4036 to 4096 m
  Length 60 m along hole
  Reference (main-basin setting).
  Well Uithuizermeeden-1 (pdf)
  Location N 53°26’58.9
E 06°48’29.2
  Depth 2194 to 2250 m
  Length 56 m along hole
  Reference (amended after NAM and RGD, 1980).(main-basin setting)
  Well P07-01 (pdf)
  Location N 52°32’43.9
E 03°11’40.6
  Depth 1797 to 1860 m
  Length 63 m along hole
  Reference (sandstone facies).
Definition The fourth cycle of the Zechstein Group consists of a claystone - anhydrite - salt sequence in the main basin and sub-basins, and a claystone - sandstone development along the basin margin.
Upper Boundary The formation comprises the strata between the Z3 (Leine) Formation and the Z5 (Ohre) or the Upper Zechstein Claystone Formation. The upper boundary is formed by the top of the Z4 Salt Member or the Z4 Pegmatite Anhydrite Member.
Lower Boundary The lower boundary has been placed at the base of the Red Salt Clay Member.
Distribution The formation is recognised in the sub-basins as well as in the main basin; in the sub-basins it is generally thin, with only a few metres of rock salt, but in the main basin the formation may reach a thickness of more than 100 m.
Age Thuringian, Late Permian.
Subdivision  
  The evaporite cycle of the Z4 (Aller) Formation is incomplete, a carbonate member and an upper anhydrite are missing. The subdivision is as follows:
  ZE Zechstein Group
  ZEZ4 Z4 (Aller) Formation
  Basin development
  ZEZ4H Z4 Salt Member
  ZEZ4A Z4 Pegmatite Anhydrite Member
  ZEZ4R Red Salt Clay Member
  Fringe development, southern offshore
  ZEZ4S Z4 Fringe Sandstone Member
  ZEZ4R Z4 Red Salt Clay Member
References See References Permian

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].