The BGS Lexicon of Named Rock Units — Result Details

Skiddaw Group

Computer Code: SKG Preferred Map Code: SkG
Status Code: Full
Age range: Tremadoc Series (O1) — Llanvirn Series (OE)
Lithological Description: Laminated siltstone and mudstone with sporadic greywacke beds and one thick sequence of greywackes (Loweswater Formation), overlain by the Eycott Volcanic Group of volcanic and sedimentary rocks. Base of Skiddaw Group not seen.
Definition of Lower Boundary: Not seen.
Definition of Upper Boundary: In the northern part of the Skiddaw inlier, the youngest siltstones and mudstones (Kirk Stile Formation) of the Skiddaw Group are unconformably overlain by volcanogenic mudstones and andesites of the Eycott Volcanic Group. In the Tarn Moor Tunnel, the youngest known strata of the Tarn Moor Formation (Skiddaw Group) are mudstones unconformably overlain by andesite lavas and volcaniclastic rocks of the Borrowdale Volcanic Group.
Thickness: Skiddaw inlier <5000m; Black Combe inlier 1000m+
Geographical Limits: The Skiddaw Group crops out in the Skiddaw, Ullswater, Bampton, Black Combe and Furness inliers in the English Lake District. Also in the Cross Fell and Teesdale inliers in northern England and it is recognised in boreholes in the Alston Block (northern England). The Skiddaw Group is unconformably overlain by volcanic rocks of the Eycott Volcanic and Borrowdale Volcanic groups or by Carboniferous limestones.
Parent Unit: Not Applicable (-)
Previous Name(s): Skiddavian (Series) (-3032)
Slates And Sandstones In Skiddaw Slates [Obsolete Name And Code: part of SKG or SKGM] (SLS)
Grits In Skiddaw Slates [Obsolete Name And Code: Part Of SKG Or SKGM] (GTSK)
Skiddaw Slate Group (-4329)
Skiddaw Group (Metasomatically Altered) [Obsolete Usage: Use SKG] (SKGM)
Skiddaw Slates [Obsolete Name And Code: See SKG And SKGM] (SKSL)
Skiddavian [Obsolete Name And Code: See SKG And SKGM] (SKVN)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The Cross Fell inlier. Cooper and Molyneux, 1990. 
Type Area  The Skiddaw inlier in the northern Lake District. Cooper et al, 1995. 
Reference(s):
Simpson, A. 1967. The stratigraphy and tectonics of the Skiddaw Slates and the relationship of the overlying Borrowdale Volcanic Series in part of the Lake District, Geological Journal, Vol.5, 391-418. 
Burgess, I C and Wadge, A J. 1974. The geology of the Cross Fell area. Explanation of 1:25 000 Geological Special Sheet comprising parts of sheets NY 53, 62, 63, 64, 71, 72, 73. (London HMSO). 91pp. 
Dixon, E E L. 1931. Whitehaven and Workington district. "In" Eastwood, T, et al. Memoirs of the Geological Survey of Great Britain. 
Ward, J C. 1832. On the geological relations of the stratified and unstratified groups of rocks composing the Cumbrian Mountains. Proceedings of the Geological Society, Vol.1, p.399. 
Cooper, A H, Rushton, A W A, Molyneux, S G, Hughes, R A, Moore, R M and Webb, B C. 1995. The stratigraphy,correlation, provenance and palaeogeography of the Skiddaw Group (Ordovician) in the English Lake District. Geological Magazine, Vol.132(2), 185-211. 
Webb, B C and Cooper, A H. 1988. Slump folds and gravity slide structures in a Lower Palaeozoic marginal basin sequence (the Skiddaw Group), NW England. Journal of Structural Geology, Vol.10(5), 463-472. 
Cooper, D C, Lee, M K, Forty, N J, Cooper, A H, Rundle, C C, Webb, B C and Allen, P M. 1988. The Crummock Water Aureole: a zone of metasomatism and source of ore metals in the English Lake District. Journal of the Geological Society, Vol.145(4), 523-540. 
Jackson, D E. 1978. The Skiddaw Group. 79-98 in Moseley, F (Ed.), The Geology of the Lake District. Yorkshire Geological Society, Occasional Publication, No.3. 
Webb, B C. 1972. North-south trending pre-cleavage folds in the Skiddaw Slate Group of the English Lake District. Nature, Physical Science, 235, 138-140. 
Fortey, N J, 1989. Low grade metamorphism in the Lower Ordovician Skiddaw Group of the Lake District, England. Proceedings of the Yorkshire Geological Society, Vol.47(4), 325-337. 
Rushton A W A. 1988. Tremadoc trilobites from the Skiddaw Group in the English Lake District. Palaeontology, Vol.31(3), 677-698. 
Eastwood, T. 1933. In Summ. Prog. Geological Survey of Great Britain for 1932. Pt 1, p.59. 
Allen, P M and Cooper, D C. 1986. The stratigraphy and composition of the Latterbarrow and Redmain sandstones, Lake District, England. Geological Journal, Vol.21, 59-76. 
Wadge, A J. 1972. Sections through the Skiddaw-Borrowdale unconformity in eastern Lakeland. Proceedings of the Yorkshire Geological Society, Vol.39, 179-198. 
Burgess, I C. 1971. Synopses of logs of Allenheads No 1 Borehole (8604 4539); and No 2 Borehole (8715 4505). Annual report of the Institute of Geological Sciences for 1970, p.33. 
Jackson, D E. 1961. Stratigraphy of the Skiddaw Group in Cumberland, England. Geological Magazine, Vol.98, 515-528. 
Rose, W C C. 1955. The sequence and structure of the Skiddaw Slates of the Lake District in the Keswick-Buttermere area. Proceedings of the Geological Association, Vol.65, 403-406 
Cooper, A H and Molyneux, S G, 1990. The age and correlation of Skiddaw Group [early Ordovician] sediments in the Cross Fell Inlier [northern England]. Geological Magazine, Vol.127, 147-157. 
Sedgwick, A and Salter, J W. 1873. A catalogue of the collection of Cambrian and Silurian fossils contained in the Geological Museum of the University of Cambridge. Cambridge, p.19. 
Fortey, R A, Beckly, A J and Rushton, A W A. 1990. International correlation of the base of the Llanvirn Series, Ordovician System. Newsletters on Stratigraphy, 22, 119-142. 
Otley, J. Remarks on the succession of rocks in the Lakes. Lonsdale Magazine, Vol.1, p.433. 
Dixon, E E L. 1925. In Summ. Prog. Geological Survey of Great Britain for 1924, 70-71. 
Shotton, F W. 1935. The stratigraphy and tectonics of the Cross Fell Inlier. Quarterly Journal of the Geological Society, Vol.91, p.652. 
Sedgwick, A. 1832. On the geological relations of the stratified and unstratified groups of rocks comprising the Cumbrian Mountains. Proceedings of the Geological Society, Vol.1, p.399. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E025 E031 E029 E022 E037 E020 E026 E023 E024 E028 E048