The BGS Lexicon of Named Rock Units — Result Details

Peterborough Member

Computer Code: PET Preferred Map Code: Pet
Status Code: Full
Age range: Callovian Age (JC) — Callovian Age (JC)
Lithological Description: Mainly brownish-grey, fissile, organic-rich (bituminous) mudstones; shelly fauna dominated by crushed aragonitic ammonites and bivalves, including nuculoid and meleagrinella shell-beds. Subordinate beds of pale-medium grey, blocky mudstone. Several bands of cementstone nodules/concretions. Basal beds commonly silty, with Gryphaea-rich shell beds.
Definition of Lower Boundary: At top of highest sandstone of underlying Kellaways Formation (this is the best definition for mapping purposes and consistency; a boundary based on the lowest mudstone is more subjective and arbitrary. This boundary is also the lower boundary of the Oxford Clay Formation.
Definition of Upper Boundary: At top of highest brownish-grey, organic-rich mudstone within thinly interbedded lithological transition (up to c.3m thick) to pale grey, calcareous mudstones of overlying 'Middle Oxford Clay' (see Stewartby Member). Inevitably, more or less arbitrary in field mapping.
Thickness: 0 - c.65m
Geographical Limits: Dorset to Humberside.
Parent Unit: Oxford Clay Formation (OXC)
Previous Name(s): Lower Oxford Clay (-2367)
Lower Oxford Clay Member [Obsolete Name And Code: See PET] (LOXC)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Active brickpits, Whittlesey, Cambridgeshire 
Reference Section  BGS Parson Drove Borehole, Parson Drove, Cambs (TF31SE/5). Depth 69.20-87.27m. 
Reference Section  Disused Brickpit (Norman Cross), Peterborough, Cambs. 
Type Area  Peterborough, Cambs. See reference sections in brickpits and borehole. 
Reference Section  Active brickpits, Whittlesey, Cambs. 
Reference Section  Disused brickpit (Yaxley), Peterborough, Cambs. 
Reference Section  Disused brickpit, (Kings Dyke), Whittlesey, Cambs. 
Reference Section  Disused brickpit, (Kings Dyke), Whittlesey, Cambs. 
Reference Section  Disused brickpit, (Kings Dyke), Whittlesey, Cambs. 
Reference Section  Active Brickpit, (Orton), Peterborough, Cambs. 
Reference Section  Disused brickpit (Dogsthorpe), Peterborough, Cambs. 
Reference(s):
Martell, D M and Hudson, J D, (Editors), 1991. Fossils of the Oxford Clay. Palaeontological Association Field Guide to Fossils No.4. 
Cox, B M, Hudson, J D and Martill, D M, 1992. Lithostratigraphic nomenclature of the Oxford Clay (Jurassic). Proceedings of the Geologists' Association, Vol.103, p.343-345. 
Horton, A, Lake, R D, Bisson, G and Coppack, B C, 1974. The geology of Peterborough. Report of the Institute of Geological Science, No.73/12. 
Duff, K L, 1975. Palaeoecology of a bituminous shale - the Lower Oxford Clay of central England. Palaeontology, Vol.18, p.443-482. 
Horton, A. 1989. Geology of the Peterborough district. Memoir of the British Geological Survey, Sheet 158 (England & Wales). 
Berridge, N G, Pattison, J, Samuel, M D A, Brandon, A, Howard, A S, Pharaoh, T C and Riley, N J. 1999. Geology of the Grantham district. Memoir of the British Geological Survey, sheet 127 (England and Wales). 
Callomon, J H, 1968. The Kellaways Beds and the Oxford clay. In Sylvester-Bradley, P C and Ford, T D. (Editors). The Geology of the East Midlands. (Leicester: Leicester University Press). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E127 E237 E159 E203 E219 E281 E341 E342 E343 E327