The BGS Lexicon of Named Rock Units — Result Details

Nettle Crags Tuff Member

Computer Code: NCT Preferred Map Code: NCT
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Massive, eutaxitic to parataxitic dacitic lapilli-tuff.
Definition of Lower Boundary: Base of dacitic lapilli-tuff above dacite lavas (and/or sills) within the Birker Fell Andesite Formation.
Definition of Upper Boundary: Non-sequence at top of dacitic lapilli-tuff. Overlain by dacite and volcaniclastic sandstone in the Birker Fell Andesite Formation.
Thickness: 60-220m
Geographical Limits: Nettle Crags - Bootle Fell in the Borrowdale Volcanic Group outcrop between the Skiddaw Group and Eskdale Granodiorite.
Parent Unit: Birker Fell Andesite Formation (BFA)
Previous Name(s): Part Of Nettle Crags Tuffs And Lavas (-2334)
Nettle Crags Tuff Formation (-1722)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Nettle Crags, 1km east north east of Bootle, Cumbria. 
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 Unpublished Ph.D. thesis, University of Sheffield. 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:
E048