The BGS Lexicon of Named Rock Units — Result Details
Conksbury Bridge Lava Member
Computer Code: | CBB | Preferred Map Code: | notEntered |
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Status Code: | Full | ||
Age range: | Brigantian Substage (CX) — Brigantian Substage (CX) | ||
Lithological Description: | In the Haddon Fields Borehole the member comprises three flows of compact and amygdaloidal basalt. At Conksbury Bridge the member includes two flows: the upper flow includes a vesicular basalt at the top and base and a central non-vesicular dolerite; the lower flow has a highly vesicular and slightly haematised upper margin, which grades down into a non-vesicular dolerite (Walters, et al., 1981). | ||
Definition of Lower Boundary: | In the Haddon Fields Borehole basalt of the Conksbury Bridge Lava Member is underlain by pale grey and cherty limestones with some calcilutites, included within the Fallgate Volcanic Formation | ||
Definition of Upper Boundary: | At Conksbury Bridge, limestone of the Monsal Dale Limestone Formation rests upon a vesicular upper margin of a 5m thick lava flow of the Conksbury Bridge Lava Member (Walters and Ineson., 1981). | ||
Thickness: | The thickest development is 51.71m, proved in the Haddon Fields Borehole. | ||
Geographical Limits: | Present at outcrop in the lower part of Lathkill Dale, north of Alport. Also proved in Boreholes at Alport [SK2365]. Occurs about 27m (Shirley, 1950) or 19m (Aitkenhead et al., 1985) above the Lathkill Lodge Lava Member. The member is not seen west of Over Haddon [SK203 663] | ||
Parent Unit: | Fallgate Volcanic Formation (FV) | ||
Previous Name(s): | Conksbury Bridge Basalt [Obsolete Name and Code: Use CBB]
(-112)
Conksbury Bridge Lava [Obsolete Name and Code: Use CBB] (-2055) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Partial Type Section | Conksbury Bridge: 3.8m of vesicular lava. Aitkenhead et al., 1985. | ||
Type Section | Haddon Fields Borehole SK26NW/25: the entire thickness of 51.71m is made of three flows. Aitkenhead et al., 1985. | ||
Reference(s): | |||
Shirley, J. 1950. The stratiographical distribution of the lead-zinc ores of Mill Close Mine, Derbyshire and the future prospects of the area. XVIII International Geological congress, London, Vol 7, 353-361. | |||
Aitkenhead, N, Chisholm, J I, and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. | |||
Walters, S G and Ineson, P R. 1981. A review of the distribution of and the correlation of igneous rocks in Derbyshire, England. Mercian Geologist, Vol. 8, 81-132. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E111 |