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): | Lower Corallian Argillaceous Group [Obsolete Name and Code: Use WWB]
(-3146)
Corallian [Obsolete Name and Code: Use AMC, WWB] (-4427) Elsworth Rock Group [Obsolete Name and Code: Use ELR, WWB] (-4635) Elsworth Rock Series [Obsolete Name and Code: Use WWB] (-1933) West Walton Beds [Obsolete Name and Code: Use ELR, WWB] (-2170) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| 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. | ||
| Type Section | West Walton Highway Borehole 3c (TF41SE/6), from 68.25m to 82.31m. Gallois and Cox, 1977; Cox and Gallois, 1979. | ||
| Reference(s): | |||
| Arkell, W J. 1933. The Jurassic System in Great Britain (Oxford: Clarendon Press.) | |||
| 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. | |||
| 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). | |||
| 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. | |||
| 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 | |||