The BGS Lexicon of Named Rock Units — Result Details

Conksbury Bridge Lava Member

Computer Code: CBB Preferred Map Code: notEntered
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 (-112)
Conksbury Bridge Lava (-2055)
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