The BGS Lexicon of Named Rock Units — Result Details

Eller Beck Formation

Computer Code:	EBB	Preferred Map Code:	notEntered
Status Code:	Full
Age range:	Aalenian Age (JA) — Bajocian Age (JB)
Lithological Description:	In the Cleveland Hills and on the North Yorkshire Coast the formation typically comprises marine ironstone, sandstone and mudstone. Two main lithological units are present; the lower unit, generally less than 3 m thick, consists of grey mudstone with subordinate sideritic ironstone, with a bed of ooidal ironstone at the base. The upper unit, typically 4-6 m thick, consists predominantly of fine- to medium-grained sandstone, commonly ripple laminated. Southwards, the formation passes into a more calcareous and finer-grained unit dominated by mudstones, argillaceous limestones and ferruginous sandstones (the "Blowgill Member" of Hemingway and Knox, 1973). Fossil marine bivalves and bioturbation are common, especially in the mudstones and ironstones. Diplocraterion burrows are commonly present in the sandstones.
Definition of Lower Boundary:	The lower boundary is conformable, at the abrupt upward transition from the plant debris-rich, cross-stratified sandstones, siltstones and mudstones of the Saltwick Formation to the fossiliferous, ooidal ironstone or ferruginous sandstone at the base of the Eller Beck Formation.
Definition of Upper Boundary:	The upper boundary is conformable, or disconformable, at the abrupt upward transition from the fossiliferous mudstone and ripple laminated sandstones of the upper part of the Eller Beck Formation to the cross-stratified, plant debris-rich sandstones, siltstones and mudstones of the Cloughton Formation (Sycarham Member).
Thickness:	Typically 4.5 to 6 m, up to a maximum of 8.2 m in the type section at Walk Mill Foss, Eller Beck, Goathland [NZ 833 023] (Barrow, 1877; Hemingway and Knox, 1973). Thins south-eastwards in the Hambleton Hills to c. 4 m thick.
Geographical Limits:	The Cleveland Hills, North York Moors, Hambleton and Howardian Hills in north-east England (Fox-Strangways, 1892; Hemingway and Knox, 1973; Hemingway, 1974). It has not been identified offshore in the Southern North Sea, but probably forms part of the Wroot Formation (Lott and Knox, 1994).
Parent Unit:	Ravenscar Group (RAG)
Previous Name(s):	Lower Estuarine "Series" [Obsolete Name And Code: See CLH, GRF, SWK And EBB] (LET) Hydraulic Limestones [Obsolete Name And Code: See SMD, BNT, ELL] (HYDL) Eller Beck Bed (-882) Blowgill Member [Obsolete Name and Code: Use EBB] (-1519)
Alternative Name(s):	none recorded or not applicable
Stratotypes:
Reference Section	The reference section for the ironstone, mudstone and limestone succession is at Skipton Hill [SE 498 843] (Powell et al., 1992, pp.41-42). The section is degraded but a trench excavation revealed yellow sandstone and mudstone with plant rootlets of the Saltwick Formation overlain by grey, yellow-weathering ironstone with a siderite matrix and berthierine ooids (Ingleby Ironstone of Knox, 1973), which passes up into grey, calcareous mudstone with bivalves and thin beds of grey siderite, overlain by grey calcareous mudstone with irregular beds of micritic limestone, yielding bivalves and gastropods (Gormire Limestone of Powell et al., 1992) and green-brown fine-to medium grained ripple cross-laminated sandstone. The upper boundary is taken at the sharp boundary with yellow medium-grained, cross-bedded sandstone with plant fragments of the overlying Cloughton Formation. Powell and Rathbone (1983) demonstrated that the supposed "Blowgill Member" of the Cloughton Formation (Hemingway and Knox, 1973) is a lateral lithofacies equivalent of the Eller Beck Formation, and not a separate, later marine transgression. The Gormire Limestone was formerly known as the Hydraulic Limestone (Fox-Strangways et al., 1886) on account of its suitability for cement making. The ostracod fauna (Bate, 1967) suggests a tentative correlation with the lower part of the Lincolnshire Limestone (Bate, 1967) of late Aalenian to early Bajocian age (Cope et al., 1980).
Type Section	The type section is at Walk Mill Foss [NZ 833 023], Eller Beck, Goathland. The formation was originally recognised here by Barrow (1877) and later adopted by Fox-Strangways (1892, p.197) for the Eller Beck Bed. It was formalized by Hemingway and Knox (1973, p.531). Here, the pale grey, plant-debris rich mudstone of the underlying Saltwick Formation are overlain by a basal transgressive sideritic ironstone, overlain by an upward-coarsening succession of mudstone (with ironstone concretions), siltstone and fine- to medium-grained sandstone. Bivalves, preserved as kaolinitic moulds, are common in the basal ironstone and the ironstone concretions; the sandstone includes sparse bivalve moulds and burrows (including Diplocraterion and Rhizocorallium) and grazing trails.
Reference(s):
Hemingway, J E. 1974. Jurassic. 161-233 in Rayner, D H and Hemingway, J E (eds), The geology and mineral resources of Yorkshire. (Leeds: Yorkshire Geological Society.)
Powell, J H and Rathbone, P A. 1983. The stratigraphical relationship of the Eller Beck Formation and the supposed Blowgill Member (Middle Jurassic) of the Yorkshire Basin. Proceedings of the Yorkshire Geological Society, Vol.44, 365-373.
Hemingway, J E and Knox, R W O'B. 1973. Lithostratigraphical nomenclature of the Middle Jurassic strata of the Yorkshire Basin of north-east England. Proceedings of the Yorkshire Geological Society, Vol.39, 527-535.
Fox-Strangways, C. 1892. The Jurassic Rocks of Britain, Vol.1. Yorkshire. Memoir of the Geological Survey of the United Kingdom.
Fox-Strangways, C, Cameron, A G and Barrow, G. 1886. The geology of the country around Northallerton and Thirsk. Memoir of the Geological Survey of England and Wales
Powell, J H, Cooper, A H C and Benfield, A C. 1992. Geology of the country around Thirsk. Memoir of the British Geological Survey, Sheet 52 (England and Wales).
Barron, A J M, Lott, G K, and Riding, J B. 2012. Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06.
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.
Barrow, G. 1887. On a new marine bed in the Lower Oolites of East Yorkshire. Geological Magazine, Vol. 4, 552-556.
Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster.
Hemingway, J E. 1949. A revised terminology and subdivision of the Middle Jurassic rocks of Yorkshire. Geological Magazine, Vol.86, 67-71.
Bate, R H. 1967. Stratigraphy and palaeoecology of the Yorkshire Oolites and their relationships with the Lincolnshire Limestone. Bulletin of the British Museum (Natural History), Geology, Vol. 14, 111-141.
Cope, J C W, Duff, K L, Parsons, C F, Torrens, H S, Wimbledon, W A and Wright, J K. 1980. A correlation of Jurassic rocks in the British Isles. Part 2: Middle and Upper Jurassic. Geological Society of London Special Report, 15, 73pp.
Knox, R W O'B. 1973. The Eller Beck Formation (Bajocian) of the Ravenscar Group of NE Yorkshire. Geological Magazine, Vol.110, 511-534.
Richards, P C, Lott, G K, Johnson, H, Knox, R W O'B. and Riding, J B. 1993. 3. Jurassic of the Central and Northern 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:
E033 E034 E035 E042 E043 E044 E052 E053 E063

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