The BGS Lexicon of Named Rock Units — Result Details
Cockermouth Volcanic Formation
Computer Code: | CKML | Preferred Map Code: | CkmL |
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Status Code: | Full | ||
Age range: | Courceyan Substage (CF) — Courceyan Substage (CF) | ||
Lithological Description: | Olivine-phyric basalt and tholeiitic andesite. Up to four sheets of massive to intensely amygdaloidal and scoriaceous rock, dark blue-grey to grey. Interpreted to be lavas. No intercalated pyroclastic or sedimentary rocks are present. | ||
Definition of Lower Boundary: | Taken at base of lowest basalt sheet that conformably overlies conglomerate of the Marsett Formation; the formation oversteps the eastwards, unconformably to overlie the Skiddaw and Eycott groups. | ||
Definition of Upper Boundary: | Conformably overlain by interbedded mudstone, sandstone and thin limestone of the Marsett Formation. | ||
Thickness: | 105m in the Cockermouth area, thinning to 30m near Sunderland; 67m thick in the type section. | ||
Geographical Limits: | Northern margin of Lake District Lower Palaeozoic massif, from just west of Cockermouth to Bothel (wholly on sheets E22 and E23). Intrusions of microgabbro ("dolerite") and lapilli-tuff on Little Mell Fell (E30 Appleby) may be intrusive equivalents of the Cockermouth Volcanic Formation (Macdonald and Walker, 1985). | ||
Parent Unit: | Ravenstonedale Group (RVS) | ||
Previous Name(s): | Cockermouth Lavas [Obsolete Name and Code: Use CKML]
(-3933)
Cockermouth Lavas Formation [Obsolete Name and Code: Use CKML] (-3934) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Area | Outcrops between Wood Hall and Redrain Bridekirk. | ||
Reference Section | Bothel Craggs Quarry, on west side of A591, about 1.5km southsoutheast of Bothel, Cumbria. Millward and Williamson. 2003. | ||
Type Section | Gill Beck, immediately south of Blindcrake, about 4.5km northeast of Cockermouth, Cumbria. Millward and Williamson. 2003. | ||
Reference(s): | |||
Millward, D, and Williamson, I T. 2003. Dinantian volcanic rocks of the Northumberland, Solway and Tweed basins. 109-143, in Stephenson, D, Loughlin, S C, Millward, D, Waters, C N and Williamson, I T. Carboniferous and Permian igneous rock of Great Britain north of the Variscan Front. Geological Conservation Review Series. No.27. (Joint Nature Conservation Committee:Peterborough). | |||
MacDonald, R and Walker, B H. 1985. Geochemistry and tectonic significance of the Lower Carboniferous Cockermouth Lavas, Cumbria. Proceedings of the Yorkshire Geological Society, Vol.45, 141-146. | |||
Eastwood, T. 1928. The Cockermouth Lavas, Cumberland - a Carboniferous volcanic episode. 15-22 in Summary of progress of the Geological Survey of Great Britain for 1927, Part 2. | |||
Eastwood, T, Hollingworth, S E, Rose, W C C, and Trotter, F M. 1968. Geology of the country around Cockermouth and Caldbeck. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 23. | |||
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. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E023 E022 E028 |