The BGS Lexicon of Named Rock Units — Result Details

Cottonshope Volcanic Formation

Computer Code: COVO Preferred Map Code: CoVo
Status Code: Full
Age range: Tournaisian Stage (CT) — Tournaisian Stage (CT)
Lithological Description: Basalt, olivine-phyric, tholeiitic; several sheets of intensely fractured dark blue-grey rock, each passing up into highly amygdaloidal, scoriaceous and pillow-like tops, which contain infills of overlying sedimentary rock. Upper part of formation is intercalated with dark grey and greenish grey sandstone and argillaceous dolostone ("cementstone") of the overlying Ballagan Formation. Interpreted as lavas.
Definition of Lower Boundary: Taken at the broadly conformable base of the lowest basalt sheet that sharply overlies a sequence of red and grey flaggy sandstones with ochreous brown spots, interbedded with purple, red lilac and green mudstone containing ochreous concretions, and thin concretionary carbonate (cornstone) beds (Lower Freestone Beds of Taylor et al, 1971), possibly part of the Kinnesswood Formation.
Definition of Upper Boundary: Taken at the base of overlying interbedded sandstone, mudstone and argillaceous dolostone sequence of the Ballagan Formation (formerly Cementstone Group); the upper contact is intercalated.
Thickness: To 24m
Geographical Limits: Southwest flanks of the Cheviot massif: exposed in Cottonshope Burn, Spithope Burn, Hungry Law, and between the Bareinghope Burn and the Chattlehope Burn, Northumberland.
Parent Unit: Inverclyde Group (INV)
Previous Name(s): Cottonshope Basalts (-158)
Cottonshope Lavas (-159)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Cottonshope Head Quarry and adjacent Cottonshope Burn, Upper Redesdale, Northumberland. Millward and Williamson (2003). 
Reference(s):
Miller, H. 1887. The geology of the country around Otterburn and Elsdon. Geological Survey Memoir, England and Wales, Sheet 8. 
Tomkeieff, S I. 1931. Lower Carboniferous igneous rocks. 259-261 in Contributions to the geology of Northumberland and Durham. Proceedings of the Geologists' Association, Vol.42. 
Taylor, B J, Burgess, I C, Land, D H, Mills, D A C, Smith, D B, and Warren, P T. 1971. Northern England. British Regional Geology (4th Edition). 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E005 E008