The BGS Lexicon of Named Rock Units — Result Details

West Walton Formation

Computer Code: WWB Preferred Map Code: WW
Status Code: Full
Age range: Oxfordian Age (JO) — Oxfordian Age (JO)
Lithological Description: Calcareous mudstone, silty mudstone and siltstone, with subordinate fine-grained sandstones and argillaceous limestone (cementstone) or siltstone nodules; typically rhythmic alternations of dark grey, silty mudstone (rich in fine-grained shell and plant material) with pale grey mudstone; ooidal, and in some cases coralline marls and limestones developed locally (including Elsworth Rock Member; Upware Limestone Member), (Gallois and Cox, 1977; Cox and Gallois, 1979).
Definition of Lower Boundary: Base of sediments as described under "Lithology" (generally the lowest dark grey, silty mudstone), resting, commonly with marked interburrowing, on pale grey, smooth-textured mudstones of the Oxford Clay Formation (Weymouth Member); commonly a marked colour change and break of slope at outcrop; change commonly well-marked on borehole geophysical (particularly gamma-ray) logs. Base of unit WW1 in type area (Cox and Gallois, 1979).
Definition of Upper Boundary: Base of pale to mid grey, smooth-textured mudstones of the Ampthill Clay Formation; generally a marked colour change and break of slope at outcrop; change commonly well-marked on borehole geophysical (particularly gamma-ray) logs. Top of unit WW16 in the type area (Cox and Gallois, 1979).
Thickness: 0 to c.20m; typically c.15m, 14.06m in type section.
Geographical Limits: Oxford area (where it passes southwestward into the Corallian Group; Horton et al., 1995) to the Market Weighton area (Gaunt et al., 1980).
Parent Unit: Ancholme Group (AMG)
Previous Name(s): Elsworth Rock Group (-4635)
Corallian (-4427)
Lower Corallian Argillaceous Group (-3146)
Elsworth Rock Series (-1933)
West Walton Beds (-2170)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  West Walton Highway Borehole 3c (TF41SE/6), from 68.25m to 82.31m. Gallois and Cox, 1977; Cox and Gallois, 1979. 
Type Area  "Fenland", ie. Boston-Wisbech area adjoining the Wash. Gallois and Cox, 1977; Gallois, 1994. 
Reference Section  Nettleton Bottom Borehole (TF19NW/54), from 256.85m to 276.88m. Gaunt et al., 1992, Appendix 4. 
Reference(s):
Edmonds, E A and Dineham, C H. 1965. Geology of the country around Huntingdon and Biggleswade. Memoir of the British Geological Survey. Sheets 187 and 204 (England and Wales). 
Gaunt, G D, Fletcher, T P and Wood, C J. 1992. Geology of the country around Kingston upon Hull and Brigg. Memoir of the British Geological Survey, sheets 80 and 89 (England and Wales). 172pp. 
Cox, B M and Gallois, R W, 1979. Description of the standard stratigraphical sequences of the Upper Kimmeridge Clay, Ampthill Clay and West Walton Beds. 68-72 in Geological investigations for the Wash Water Storage Scheme. Gallois, R W. Report of the Institute of Geological Sciences, No.78/19. 
Gallois, R W, 1994. The geology of the country around King's Lynn and The Wash. Memoir of the British Geological Survey, Sheet 145 and part of 129 (England and Wales). 
Gallois, R W and Cox, B M. 1977. The stratigraphy of the Middle and Upper Oxfordian sediments of Fenland. Proceedings of the Geologists' Association, Vol.88, 207-228. 
Gaunt, G D, Ivimey-Cook, H C, Penn, I E and Cox, B M. 1980. Mesozoic rocks proved by the Institute of Geological Sciences boreholes in the Humber and Acklam areas. Report of the Institute of Geological Sciences, No. 79/13. 
Arkell W J, 1933. The Jurassic System in Great Britain [Oxford: Clarendon Press.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E080 E102 E103 E104 E115 E116 E128 E129 E145 E144 E159 E172 E187 E204 E220 E236 E237 E081 E203 E173 E188 E219