The BGS Lexicon of Named Rock Units — Result Details

Fell Green Formation [Obsolete Name: Part Of BFA]

Computer Code: FGR Preferred Map Code: FGr
Status Code: Index Level
Age range: Abereiddian Stage (O2) — Caradoc Series (O4)
Lithological Description: Dacite lavas or sills with intercalated volcanogenic sandstone.
Definition of Lower Boundary: Unconformity or thrust fault at base of Borrowdale Volcanic Group on Skiddaw Group.
Definition of Upper Boundary: Non-sequence:- at top of dacite succession below the Nettle Crags Tuff Formation.
Thickness: 100-150m
Geographical Limits: Fell Green - Bootle Fell, between the Skiddaw Group and the Eskdale Granodiorite.
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Not Previously Named, Included As Part Of Nettle Crags Tuffs And Lavas (-4649)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Near Fell Green, Bootle, Cumbria; between Crookley Beck and Nettle Crags. 
Reference(s):
British Geological Survey, 1994. Black Combe and Bootle, SD18NW, Solid and Drift 1:10,000 (Keyworth, Nottingham, British Geological Survey). 
Mathieson, N A, 1986 Geology, structure and geochemistry of the Ordovician volcanic succession in south west Cumbria. Unpublished Ph.D. thesis, University of Sheffield. 
Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable