The BGS Lexicon of Named Rock Units — Result Details

Fordon Evaporite Formation

Computer Code: FOEV Preferred Map Code: FOEV
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: A thick and varied sequence of evaporites including anhydrite and halite, with some gypsum and dolostone. Passes laterally into Seaham Residue at outcrop in Durham, and into part of Edlington Formation in Yorkshire outcrop.
Definition of Lower Boundary: In the Durham province: contact (gradational transition) with the underlying Roker Formation (including the Concretionary Limestone Member) dolostone, marked by the incoming of evaporite rocks. In the Yorkshire province:contact with the top of the Kirkham Abbey Formation dolostone, the incoming of evaporite rocks.
Definition of Upper Boundary: Drawn at base of Brotherton Formation (Yorkshire province) or Seaham Formation (Durham province], marked by the incoming of limestone.(Stated as base of Upper Magnesian Limestone in Smith, et al., 1974).
Thickness: 396m in type section; thins to small residue at outcrop.
Geographical Limits: Zechstein Basin of Northeast England.
Parent Unit: Zechstein Group (ZG)
Previous Name(s): Lower Evaporites, Lower Evaporite Group, Also Fordon Evaporite(s) (-257)
Fordon Evaporites [Obsolete Code: Use FOEV] (PDE)
Fordon Evaporite [Obsolete Code: Use FOEV] (FOE)
Fordon Evaporites (Obsolete Code: Use Foev) (-4652)
Alternative Name(s): Seaham Residue [Mudstone]
Lower Evaporites.
Stratotypes:
Type Section  Fordon No. 1 Borehole from 1891.3 m. to 2286.7 m. depth, Stewart 1963. Stewart, 1963; as Lower Evaporites. 
Reference Section  Offshore borehole No.WM 7A . Smith, 1994, page 105-108. 
Reference(s):
Stewart, F H. 1963.(as the Lower Evaporites) The Permian Lower Evaporites of Fordon in Yorkshire. Proceedings of the Yorkshire Geological Society. Vol. 34, p. 1 - 44. 
Raymond, L R. 1953. Some geological results from the exploration for potash in north-east Yorkshire. Quarterly Journal of the Geological Society of London, Vol. 108, p. 283 - 310. 
Napier, E. 1948. The lower anhydrite seam of the Tees area. Proceedings of the Yorkshire Geological Society, Vol. 27, p. 210 - 216. 
Falcon, N L and Kent, P. 1960. Geological results of petroleum exploration in Britain, 1945-1957. Geological Society of London, Memoir, 2, 1-56. 
Smith, D B, Brunstrom, R G W, Manning, D I, Simpson, S and Shotton, F W. 1974. A correlation of Permian rocks in the British Isles. Geological Society of London Special Report No. 5. 
Stewart, F H, 1949. The petrology of the evaporites of the Eskdale No.2 boring, East Yorkshire, Part 1: The lower evaporite bed. Mineralogical Magazine, Vol.161.28, 621-675. 
Smith, D B, 1994. Geology of the country around Sunderland. Memoir of the British Geological Survey, Sheet 21, (England and Wales). 
Smith, D B, Harwood, G M, Pattison, J and Pettigrew, T H. 1986. A revised nomenclature for Upper Permian strata in eastern England. 9-17 in Harwood, G M and Smith, D B (editors). The English Zechstein and Related Topics. Geological Society Special Publication No.22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E021 E081 E055 E065 E090 E091 E027