The BGS Lexicon of Named Rock Units — Result Details

Builth Volcanic Group

Computer Code: BUVO Preferred Map Code: notEntered
Status Code: Full
Age range: Abereiddian Stage (O2) — Abereiddian Stage (O2)
Lithological Description: Red agglomerate and ashes, fine-grained grey ashes and shales, pebbly feldspar ashes, bouldery spilitic ashes, spilites, felsite agglomerate, keratophyres, breccias and ashes.
Definition of Lower Boundary: Drawn at the base of the red agglomerate and ashes formation where they rest unconformably upon the Landrindod and Shale Group.
Definition of Upper Boundary: Drawn at the conformable upward passage of the keratophyres, breccias and ashes group with the base of the Newmead Group.
Thickness: 609 m.
Geographical Limits: Radnorshire, near Builth Wells.
Parent Unit: Not Applicable (-)
Previous Name(s): Builth Volcanic Formation [Obsolete Name And Code: Use BUVO] (BUV)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Maen-Gowan, 3 km northeast of Builth, Radnorshire. 
Reference(s):
Schofield, D I, Davies, J R, Waters, R A, Williams, M and Wilson, D. 2004. The Builth Wells District - a brief explanation of the geology. Sheet explanation of the British Geological Survey 1:50 000 Sheet 196 Builth Wells (England and Wales). (Keyworth, Nottingham: British Geological Survey). 
George, T N. 1970. British Regional Geology, South Wales, Third Edition. British Geological Survey. 
Jones, O T and Pugh, W J. 1941. The Ordovician rocks of the Builth District. A preliminary account. Geological Magazine, Vol.78, p.190. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable