The BGS Lexicon of Named Rock Units — Result Details

Cropwell Bishop Formation [Obsolete Name And Code: Use BCMU]

Computer Code: CBP Preferred Map Code: CBp
Status Code: Index Level
Age range: Norian Age (TN) — Rhaetian Age (TR)
Lithological Description: Mudstone and siltstone, reddish brown, blocky; common veins, nodules and beds of gypsum; a few beds of dolomitic sandstone.
Definition of Lower Boundary: Gradational; taken at top of highest significant sandstone bed of the underlying Hollygate Sandstone Member (Edwalton Formation).
Definition of Upper Boundary: Sharp, apparantly conformable, marked by colour change into grey-green siltstones of the Blue Anchor Formation.
Thickness: 30 to 45m (38m in Fulbeck 1 Borehole, SK85SE/25).
Geographical Limits: Mapped at surface in Nottinghamshire and Leicestershire. Recognisable in subsurface throughout East Midlands and NE England; passes laterally into thicker equivalents in central Midlands and Cheshire Basin.
Parent Unit: Mercia Mudstone Group (MMG)
Previous Name(s): Trent Formation + Glen Parva Formation (-2672)
Trent Formation [Obsolete Name And Code: Part Of CBP] (TNT)
Glen Parva Formation [Obsolete Name And Code: Part Of CBP] (GPV)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Fulbeck 1 Borehole (SK85SE/25), Fulbeck, Lincs.; depth range 117.5m-156.1m; curated core held at BGS Keyworth. 
Type Section  Composite stratotype, providing complete section: Cropwell Bishop Gypsum Quarry, Cropwell Bishop, Nottinghamshire and nearby Cropwell Bridge Borehole (SK63NE/28); depth range 0-35.8m; curated core held at BGS Keyworth. 
Reference Section  Bantycock Gypsum Quarry, 4km SSE of Newark, Notts. Exposes upper 25m of formation with upper boundary. 
Reference(s):
Charsley, T J, Rathbone, P A and Lowe, D J, 1990. Nottingham: A geological background for planning and development. British Geological Survey Technical Report WA/90/1. 
Elliott, R E 1961. The stratigraphy of the Keuper Series in southern Notinghamshire. Proceedings of the Yorkshire Geological Society, Vol.33, 197-231. 
Warrington, G, Audley-Charles, M G, Elliott, R E, Evans, W B, Ivimey-Cook, H C, Kent, P E, Robinson, P L, Shotton, F W and Taylor, F M. 1980. A correlation of the Triassic rocks in the British Isles. Special Report of the Geological Society of London, No.13. 
Lowe, D J, 1989. Geology of the Cropwell Butler district. 1:10,000 Sheet SK63NE: Part of 1:50,000 Sheet 126, Nottingham and Sheet 142, Melton Mowbray. British Geological Survey, Onshore Geology Series Technical Report 89/10. 
Howard, A S, Warrington, G, Ambrose, K, and Rees, J G. 2008. A formational framework for the Mercia Mudstone Group (Triassic) of England and Wales. British Geological Survey Research Report, RR/08/04. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E126 E127 E142 E141