The BGS Lexicon of Named Rock Units — Result Details

Ford Formation

Computer Code: FML Preferred Map Code: FORD
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: Dolomite that comprises three distinct facies: shelf-edge reef that separates a broad belt of back-reef and lagoonal beds to the west from a belt of fore-reef talus aprons and off-reef beds to the east.
Definition of Lower Boundary: The incoming of oolitic and pisolitic or reef equivalent dolostone above the fine-grained dolostone of the Raisby Formation. Boundary is transgressive, overlapping older Permian formations to lie unconformably on Carboniferous rocks.
Definition of Upper Boundary: Either the sharp, conformable base of the overlying anhydrites of the Hartlepool Anhydrite Formation or the reddish-brown mudstone and siltstone of the Edlington Formation
Thickness: 1 - 150m, generally 100 - 120m
Geographical Limits: Durham province, County Durham, Tyne and Wear, Cleveland and northernmost North Yorkshire.
Parent Unit: Zechstein Group (ZG)
Previous Name(s): Middle Magnesian Limestone [Obsolete Name And Code: See FML] (MMGL)
Ford [Magnesian Limestone] Formation (-911)
Alternative Name(s): Sprotbrough Member
Stratotypes:
Type Area  Ford Quarry and Claxheugh Rock, South Hylton, Sunderland, Tyne and Wear, for reef and back-reef facies. Smith, D B et al. 1986, p. 14; Smith, D B. 1995, p. 58. 
Reference(s):
Smith, D B, 1995. Marine Permian of England. Geological Conservation Review Series No. 8. [London: Chapman and Hall.] 
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. 
Smith, D B and Francis, E A. 1967. Geology of the country between Durham and West Hartlepool. Memoir of the Geological Survey of Great Britain, Sheet 27 (England and Wales). 
Smith, D B, 1970. The palaeogeography of the English Zechstein. "In" Rav, J L and Dellwig, L F. (Editors). Third Symposium on Salt, Northern Ohio Geological Society, Vol.1, 20-23. 
Smith, D B, 1981. The Magnesian Limestone (Upper Permian) reef complex of north-eastern England. "In" Toomey, D F. (Editor). European Fossil Reef Models. Special Publication of the Society of Economic Palaeontologists and Mineralogists, Tulsa, Vol.30, 161-186. 
Smith, D B, 1994. Geology of the country around Sunderland. Memoir of the British Geological Survey, Sheet 21, (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E033 E021 E027 E032 E041 E042 E026 E015