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):
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. 
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 Unpublished Ph.D. thesis, University of Sheffield. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable