The BGS Lexicon of Named Rock Units — Result Details
Grey Shale Member
| Computer Code: | GREY | Preferred Map Code: | GSh |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Toarcian Age (JT) — Toarcian Age (JT) | ||
| Lithological Description: | Mudstone and siltstone, grey, shaly, with layers of small calcareous and ferruginous nodules; fossiliferous, with common ammonites in upper beds; laminated and bituminous in parts | ||
| Definition of Lower Boundary: | Conformable: base of mudstone resting upon ooidal limestone, ironstone or sideritic mudstone nodules of the Cleveland Ironstone Formation. Bed 43 on Bed 42 at Hawsker Bottoms; Bed 57 on Bed 56 at Port Mulgrave (bed numbers of Howarth, 1955). | ||
| Definition of Upper Boundary: | Conformable: base of bituminous mudstone with large concretions (Mulgrave Shale Member) resting upon non-bituminous shaly mudstone. Bed 33 on Bed 32 at Hawsker Bottoms and Port Mulgrave (bed numbers of Howarth, 1955). | ||
| Thickness: | 12 to 17m thick on the Yorkshire coast, thinning west and south to between 5 and 7m (Felixkirk and Brown Moor boreholes). | ||
| Geographical Limits: | Cleveland Basin as far south as Acklam area, becomes indistinguishable southwards (see Supplementary Information). | ||
| Parent Unit: | Whitby Mudstone Formation (WHM) | ||
| Previous Name(s): | Grey Shales [Obsolete Name and Code: Use GREY]
(-1573)
Grey Shale Series [Obsolete Name and Code: Use GREY] (-3442) Grey Shales Formation [Obsolete Name and Code: Use GREY] (-2214) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Fully exposed in continuous foreshore at Port Mulgrave, North Yorkshire coast, 12 to 15m thick. Beds 57 to 60 and 1 to 32 of Howarth (1955). Simms et al. 2004, pp 281-293. | ||
| Type Section | Fully exposed in cliffs and foreshore east of Hawsker Bottoms, North Yorkshire coast, between 16 and 17m thick. Beds 43 to 44 and 1 to 32 of Howarth (1955) Powell, 1984 (gives NGR of NZ 951 077); Simms et al. 2004, pp 262-271. | ||
| Reference(s): | |||
| Fox-Strangways, C and Barrow, G, 1915. The geology of the country between Whitby and Scarborough (2nd edition). Memoir of the Geological Survey of the United Kingdom. | |||
| Arkell, W J. 1933. The Jurassic System in Great Britain (Oxford: Clarendon Press.) | |||
| Simms, M J, Chidlaw, N, Morton, N, and Page, K N. 2004. British Lower Jurassic Stratigraphy. Geological Conservation Review Series. No. 30. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) | |||
| Tate, R, and Blake, J F. 1876. The Yorkshire Lias. (London: J van Voorst.) | |||
| Cox, B M, Sumbler, M G, and Ivimey-Cook, H C. 1999. A Formational framework for the Lower Jurassic of England and Wales (Onshore Area). British Geological Survey Research Report No. RR/99/01. | |||
| Powell, J H, 1984. Lithostratigraphic nomenclature of the Lias Group in the Yorkshire Basin. Proceedings of the Yorkshire Geological Society, Vol.45, p.51-57. | |||
| Howarth, M K, 1980, Toarcian correlation chart, in Cope, J C W (editor). 1980. A correlation of the Jurassic rocks of the British Isles. Part One: Introduction and Lower Jurassic. Geological Society of London Special Report. No. 14. | |||
| Howarth, M K, 1955. Domerian of the Yorkshire coast. Proceedings of the Yorkshire Geological Society, Vol.30, 147-175. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||