The BGS Lexicon of Named Rock Units — Result Details

Speeton Clay Formation

Computer Code: SPC Preferred Map Code: SpC
Status Code: Full
Age range: Berriasian Age (KR) — Albian Age (KA)
Lithological Description: The Speeton Clay Formation comprises mudstones, cementstones and sporadic bentonites. It was divided by Lamplugh (1889), into five units (E to A from the base up) related to belemnite content, and these divisions are still maintained. E Bed: The basal bed comprises mainly phosphatic nodules with scattered rolled and fragmented, pyritised and phosphatised bivalves, ammonites and bone, and is usually referred to as the Coprolite Bed (Lamplugh, 1923). There is a marked break in the succession at the base of this bed and a less obvious one at its top. D Beds: Black shale is overlain by greenish-brown, brown and grey clays and includes the Blue Bed (D6), the Ligula Bed (D5), the Astarte Bed (D4) and the D3 Bed (un-named). A compound nodular bed (Bed D1) occurs at the top of the "D beds". A significant break in the succession occurs between Beds D2D and D2E. These beds are also historically known as the Lateralis Beds (Lamplugh, 1923). C Beds: Alternations of pale and dark grey clays and shaley clays are characteristic of these beds. Nodules and glauconite occur at some levels. Includes the Main Speetonensis Bed (C6) and the Echinospatangus Bed (C3). Historically known also as the Jaculum Beds (Lamplugh, 1923). B Beds: A lower part of pale and dark grey and blue-grey clays with nodules and pyritous at some horizons passes upwards into the "Cement Beds" and into an upper succession of striped blue, black and grey clays with nodules. Historically known also as the Brunsvicensis Beds (Lamplugh, 1923). A Beds: Grey and brown calcareous clays passing up into glauconitic clays with nodules (the "Greensand Streak", Bed A7) and up into grey, red and mottled calcareous clays. Known as the "Ewaldi Marl" below and the "Minimus Marl" above the Greensand Streak (Lamplugh, 1923) (Ewaldi Beds and Minimus Marls of Rawson (1992) and Rawson and Wright (2000)).
Definition of Lower Boundary: The base is taken where grey and black clays (the D Beds of the Speeton Clay Formation) on a thin, but prominent, pyritized and phosphatized basal bed (E Bed) rest on dark grey to black mudstones of the Kimmeridge Clay Formation, which has an eroded upper surface.
Definition of Upper Boundary: The upper boundary is at a sharp contact where brown and grey-green, glauconitic and calcareous clays, with horizons of phosphatic nodules, that form the A Beds of the Speeton Clay are overlain by nodular and almost entirely red limestone (one bed near the base is white) of the Hunstanton Formation.
Thickness: To 100 m at outcrop, but possibly up to c. 400 m in boreholes [Rawson et al., 1978].
Geographical Limits: The Formation is exposed along the coast at the southern end of Filey Bay. The outcrop is rarely exposed inland, but extends as a narrow strip along the northern edge of the Chalk Wolds to Granton, East Heslerton, West Heslerton to south of Knapton [1:50 000 sheets 54 and 55]. It has been penetrated in several boreholes, located on the Chalk Wolds, including the Fordon 1 Borehole TA07NE1 [TA 05834 75713], North Fordon G1 Borehole TA07NW1 [TA 04138 76860], Fordon G2 TA07NW2[TA 04724 75377], Fordon G3 TA07NW3 [TA 02027 76395], Reighton Borehole TA17NW12 [TA 1465 7581] and Hunmanby TA17NW10 [TA 1301 7588]. It is also said to have been penetrated in boreholes on the Great Driffield sheet (64). The formation was recognized in the North Sea by Rhys [1974], but the offshore succession and has since been divided into the Carrack and Valhall formations (Johnson and Lott, 1993; Lott and Knox, 1994).
Parent Unit: Cromer Knoll Group (CRKN)
Previous Name(s): Neocomian Strata (*702)
Speeton Series (-2439)
Upper Shale (-2440)
Speeton Clay (-4897)
Alternative Name(s): Neocomian Strata
Stratotypes:
Type Section  1.5km length of coast at the southern end of Filey Bay between Reighton Gap and Dulcey Dock, Speeton Cliffs. Many partial sections within slipped, steep coastal cliffs. The complete section has been built up over many years as appropriate parts of the succession became available. Lamplugh, 1889. For details, see individual references. 
Reference(s):
Lamplugh, G W. 1896. On the Speeton Series in Yorkshire and Lincolnshire. Quarterly Journal of the Geological Society, London, Vol.52, 179-220. 
Judd, J W. 1868. On the Speeton Clay. Quarterly Journal of the Geological Society, Vol.24, 218-250. 
Kaye, P. 1964. Observations on the Speeton Clay [Lower Cretaceous]. Geological Magazine, Vol.101, 340-356. 
Neale, J W. 1962. Ammonoidea from the Lower D Beds [Berriasian] of the Speeton Clay. Palaeontology, Vol.5, 272-296. 
Neale, J W. 1974. Cretaceous. 225-245 in Rayner, D H and Hemingway, J E (editors), The geology and mineral resources of Yorkshire. (Leeds: Yorkshire Geological Society.) 
Lamplugh, G W. 1889. On the subdivisions of the Speeton Clay. Quarterly Journal of the Geological Society, London, Vol.45, 575-618. 
Ennis, W C. 1937. The upper beds of the Speeton Clay. Transactions of the Hull Geological Society, Vol.7, 130-138. 
Fletcher, B N. 1969. A lithological subdivision of the Speeton Clay C Beds (Hauterivian), East Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.37, 323-327. 
Johnson, H and Lott, G K. 1993. Cretaceous of the Central and Northern North Sea. In Knox, R W O'B and Cordey, W G (editors), Lithostratigraphic nomenclature of the UK North Sea. (Nottingham: British Geological Survey.) 
Judd, J W. 1870. Additional observations on the Neocomian strata of Yorkshire and Lincolnshire, with notes on their relationships to the beds of the same age throughout Northern Europe. Proceedings of the Geological Society, Vol.26, 326-348. 
Knox, R W O'B, and Fletcher, B N. 1978. Bentonites in the Lower D Beds (Ryazanian) of the Speeton Clay of Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.42, 21-27. 
Lamplugh, G W. 1924. A review of the Speeton Clays. Proceedings of the Geological Society, Vol.20, 1-31. 
Mitchell, S F and Underwood, C J. 1999. Lithological and faunal stratigraphy of the Aptian and Albian [Lower Cretaceous] of the type Speeton Clay, Speeton, North East England. Proceedings of the Yorkshire Geological Society, Vol.52, 277-296. 
Neale, J W. 1960. The subdivision of the Upper D beds of the Speeton Clay of Speeton, East Yorkshire. Geological Magazine, Vol.97, 353-362. 
Neale, J W. 1968. Biofacies and lithofacies of the Speeton Clay D Beds, East Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.36, 309-335. 
Rawson, P F, Curry, D, Dilley, F C, Hancock, J M, Kennedy, W J, Neale, J W, Wood, C J and Worrsam, B C. 1978. A correlation of Cretaceous rocks in the British Isles. Geological Society of London, Special Report No.9. 
Swinnerton, H H. 1936-1955. A monograph of British Lower Cretaceous Belemnites, Monograph of the Palaeontographical Society, 86pp. 
Young, G and Bird, J. 1822. A geological survey of the Yorkshire coast: describing the strata and fossils occurring between the Humber and the Tees, from the German ocean to the plain of York. First edition. (Whitby: Clark.) 
Rawson, P F, and Mutterlose, J. 1983. Stratigraphy of the Lower B and basal Cement Beds (Barremian) of the Speeton Clay, Yorkshire, England. Proceedings of the Geologists' Association, Vol.94, 133-146. 
Rhys, G H. 1974. A proposed standard lithostratigraphic nomenclature for the southern North Sea and an outline structural nomenclature for the whole of the (UK) North Sea. Report of the Institute of Geological Sciences, 74/8. 
Phillips, J. 1829. Illustrations of the geology of Yorkshire, or a description of the strata and organic remains. Part I, the Yorkshire Coast. (York.) 
Lott, G K and Knox, R W O'B. 1994. 7. Post-Triassic of the Southern North Sea. In: Knox, R W O'B and Cordey, W G (eds.) Lithostratigraphic nomenclature of the UK North Sea. [British Geological Survey, Nottingham]. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E055 E064 E065 E054