The BGS Lexicon of Named Rock Units — Result Details

Wensleydale Group [Obsolete Name And Code: Use YORE]

Computer Code: WND Preferred Map Code: Wnd
Status Code: Index Level
Age range: Brigantian Substage (CX) — Pendleian Substage (CE)
Lithological Description: Cyclothermic alternation (5m-80m thickness per rythm) in upward sequence ideally of fossiliferous limestone and coarsening upward siliciclastics (mudstone, siltstone and sandstone) topped by 'seatearth' and coal. The cycles vary greatly in thickness since all the elements of any rhythm may be reduced or absent.
Definition of Lower Boundary: On the northern Askrigg Block, at the lower boundary of the Wensleydale Group, the light to medium-grey limestones (with palaeokarst surfaces) and subordinate mudstones of the Danny Bridge Limestone Formation pass upward into the cross-bedded, regressive sandstones of the Thorney Force Sandstone Member, Alston Formation. In the Settle area the lower boundary of the Wensleydale Group is generally taken where the lighter grey, thick to very thick bedded limestones with palaeokarst surfaces of the Malham Formation pass upward into the darker grey Lower Hawes Limestone at the base of the Yoredale facies sequence.
Definition of Upper Boundary: To the north of Wensleydale on the Askrigg Block, strata above the Crow Limestone, Wensleydale Group include mudstones (with sporadic beds with sideritic nodules) and thin limestones that pass unconformably upward into pebbly, cross-bedded sandstone of the Lower Howgate Edge Grit, Millstone Grit Group. In the Settle area the upper boundary of the Wensleydale Group is marked by the same gentle unconformity between the mudstones and siltstones above the Main Limestone and the overlying, overstepping, massive to cross-bedded, coarse-grained, pebbly sandstone of the Grassington Grit Formation, Millstone Grit Group.
Thickness: Generalised vertical sections for 1:50 000 scale Sheets 40,41,50 and 60 (England and Wales) suggest thickness of about 816m, 370m, 910m and 216m respectively.
Geographical Limits: Askrigg Block
Parent Unit: Not Entered (?)
Previous Name(s): Wensleydale Formation (-3767)
Alternative Name(s): Yoredale Group
Stratotypes:
Type Area  Type area is upper Wensleydale, northern Askrigg Block. The approximate National Grid Reference given below relates to Horton in Ribblesdale, presumed to be the section depicted by George et al. (1976, fig.11C). Phillips (1836), Moore (1958), George et al. (1976), Dunham and Wilson (1985), Athurton et al. (1988). 
Reference(s):
Arthurton, R S, Johnson, E W and Mundy, D J C. 1988. Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (England and Wales). 
Phillips J, 1836. Illustrations of the Geology of Yorkshire, Part ii. The Mountain Limestone District. (London:John Murray). 
George, T N, Johnson, G A L, Mitchell, M, Prentice, J E, Ramsbottam, W H C, Sevastopulo, G D and Wilson, R B. 1976. A correlation of the Dinantian rocks of the British Isles. Special Report of the Geological Society of London, No 7. 
Moore,D.1958. The Yoredale Series of Upper Wensleydale and adjacent parts of north-west Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.31, 91-148. 
Waters, C N, Brown, M A E, Dean, M T and Powell, J H. In press. Lithostratigraphical framework for Carboniferous successions of Great Britain (Onshore). British Geological Survey Research Report, RR/05/06. 
Aitkenhead, N. 2002. British regional geology: the Pennines and adjacent areas (4th edition). ( London: HMSO for the British Geological Survey.) 
Burgess, I., and Mitchell, M. 1976. Visean lower Yoredale limestones on the Alston and Askrigg blocks and the base of the D2 Zone in northern England. Proceedings of the Yorkshire Geological Society, Vol.40, 613-630. 
Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. 
Dunham, K C, and Wilson, A A. 1985. Geology of the Northern Pennine Orefield. Volume 2 Stainmore to Craven. Economic Memoir of the British Geological Survey, Sheets 40, 41 and 50, and parts of Sheets 31, 32, 51, 60 and 61(England and Wales). 
Kelling,G., and Collinson,J.D. 1992. Silesian. 239-273 in Duff,P.McL.D. and Smith,A.J. (editors). Geology of England and Wales. (London: The Geological Society.) 
Leeder,M.R. 1992. Dinantian. 207-238 in Duff,P.McL.D., and Smith,A.J.(editors). Geology of England and Wales. (London: The Geological Society.) 
Ramsbottom,W.H.C.1977.Major cycles of transgression and regression(mesothems) in the Namurian.Proceedings of the Yorkshire Geological Society,Vol.41,261-291. 
Ramsbottom, W H C, Calver, M A, Eagar, R M C, Hodson, F, Holliday, D W, Stubblefield, C J and Wilson, R B. 1978. A correlation of the Silesian rocks in the British Isles. Geological Society of London, Special Report No.10. 
Brandon, A, Riley, N J, Wilson, A A and Ellison, R A. 1995. Three new early Namurian (E1c-E2a) marine bands in central and northern England, UK, and their bearing on correlations with the Askrigg Block. Proceedings of the Yorkshire Geological Society, Vol.50, 333-355. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E040 E041 E050 E060