The BGS Lexicon of Named Rock Units — Result Details

Hebden Formation

Computer Code: HEBD Preferred Map Code: notEntered
Status Code: Full
Age range: Kinderscoutian Substage (CK) — Kinderscoutian Substage (CK)
Lithological Description: Fine- to very coarse-grained and pebbly, feldspathic sandstone interbedded with grey siltstone and mudstone, with subordinate marine black shales, thin coals and seatearths. The lower part of the formation is dominated by a turbiditic facies of thinly interbedded siltstone and fine-grained sandstone with laterally impersistent and locally thick, massive, coarse to very coarse-grained sandstones. The upper part of the formation is dominated by sheet-like laterally persistent, cross-bedded sandstones, interbedded with siltstone and mudstone; Coal and seatearth are largely restricted to the upper part of the formation. A distinctive feature of the lower part of the formation within the Askrigg Block succession is the presence of brachiopod-bearing sandstones, the Cayton Gill Shell Bed and Ure Shell Bed (Wilson and Thompson, 1965; Wilson, 1977).
Definition of Lower Boundary: The base of the dark grey, shaly mudstone Hodsonites magistrorum Marine Band with eponymous fauna, where the formation overlies the mudstone-dominated Samlesbury Formation. Elsewhere, where this marine band has not been found, the base of the formation equates with the base of the Cayton Gill Shale in the south of the Askrigg Block (Wilson, 1977) and the base of the Mousegill Marine Beds in the Stainmore Trough (Owens and Burgess, 1965). In the south of the Central Pennine Basin the base is taken at the base of the first thick quartz-feldspathic sandstone of Kinderscoutian age, present above the Bowland Shale Formation.
Definition of Upper Boundary: The sharp conformable base of the dark grey, shaly mudstone of the Bilinguites gracilis Marine Band with eponymous fauna, typically overlain by mudstone of the Marsden Formation.The marine band is underlain by sandstone including the Upper Kinderscout Grit of the Hebden Formation. Elsewhere, where the marine band is absent, in the Askrigg Block the top of the formation is taken at the base of the Wandley Gill Shale, described by Wilson and Thompson (1965) as 3 m of shale with a Lingula Band at the base, overlying a seatearth at the top of the Upper Brimham Grit. In the Stainmore Trough the top of the formation is taken at the base of a 6 m thick shale with Productus carbonarius, which overlies a 0.15m-thick shaly coal (Owens and Burgess, 1965).
Thickness: Preston 335m, Bradford 275m and Derbyshire 600m thick; southern part of the Askrigg Block about 100m; Stainmore Trough 40m.
Geographical Limits: North Lancashire and north Yorkshire, between Lancaster [SD 47 61] and Harrogate [SE 30 55], extending southward to north Derbyshire [SK18] and on the Askrigg Block and Stainmore Trough.
Parent Unit: Millstone Grit Group [See Also MIGR] (MG)
Previous Name(s): Kirkbeck Formation [Obsolete Name And Code: See SAML And HEBD] (KBF)
Kinderscout Grit Group (-1590)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Crimsworth Dean, north of Hebden Bridge, shows the upper boundary with the Marsden Formation, as a transitiion from the underlying turbiditic facies to the overlying fluvial sheet sandstone facies. Stephens et al, 1953; Davies and Mclean, 1996. 
Partial Type Section  Blackden Brook, Kinder Scout, Derbyshire provides an excellent stream section of 150 m thickness of the Shale Grit, Grindslow Shales and the base of the Kinderscout Grit. Stevenson and Gaunt, 1971; Davies and Mclean, 1996. 
Reference(s):
Waters, C N, Barclay, W J, Davies, J R and Waters, R A. In press. Stratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/05/06. 
Brandon, A, Aitkenhead, N, Crofts, R G, Ellison, R A, Evans, D J and Riley, JN J, 1998. Geology of the country around Lancaster. Memoir of the British Geological Survey, Sheet 59 (England and Wales). 
Wilson, A A. 1977. The Namurian rocks of the Fewston area. Transactions of the Leeds Geological Association, Vol.9, 1-42. 
Owens, B and Burgess, I C. 1965. The stratigraphy and palynology of the Upper Carboniferous outlier of Stainmore, Westmorland. Bulletin of the Geological Survey of Great Britain, N.23, 17-44. 
Price, D, Wright, W B, Jones, R C B, Tonks, L H and Whitehead, T H. 1963. Geology of the country around Preston. Memoir of the Geological Survey of Great Britain, Sheet 75 (England and Wales). 
Stephens, J V, Mitchell, G H and Edwards, W N. 1953. Geology of the country between Bradford and Skipton. Memoir of the Geological Survey of Great Britain, Sheet 69 (England and Wales). 
Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. 
Davies, S J and Mclean, D. 1996. Spectral gamma-ray and palynological characterization of Kinderscoutian marine bands in the Namurian of the Pennine Basin. Proceedings of the Yorkshire Geological Society, Vol. 51, 103-114. 
Wilson, A A and Thompson, A T. 1965. The Carboniferous section in the Kirkby Malzeard area, Yorkshire. Proceedings of the Yorkshire Geological Society. Vol 35, 203-227. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E059 E068 E069 E070 E075 E076 E077 E086 E099