The BGS Lexicon of Named Rock Units — Result Details

Whorneyside Tuff Formation

Computer Code: WNY Preferred Map Code: Wny
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Brown-weatherd, massive eutaxitic andestic lapilli-tuff overlain by laminated and thinly bedded andesitic tuff. Intruded by many contemporaneous andesite sills in part.
Definition of Lower Boundary: Base of andesitic lapilli-tuff or, where that is absent, at base of bedded andesitic tuff. Markedly unconformable on the succession of Birker Fell Andesite Formation lavas that range in composition from basalt to dacite.
Definition of Upper Boundary: Contact with overlying rhyodacitic rocks in the Airy's Bridge Tuff Formation.
Thickness: 0 - 450m
Geographical Limits: Whorneyside, Langdale to Scafell, Wasdale, Borrowdale; Coniston Fells, Hard Knott and Duddon Valley, Cumbria.
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Whorneyside Formation (-1925)
Crosby Thwaite Formation [Obsolete Name And Code: Subsumed Within WNY] (CYT)
Worm Crag Formation [Obsolete Name: Rocks Now Included In WNY And AIB] (WCF)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Whorneyside Waterfall, Crinkle Crags. 
Reference(s):
Millward, D, Johnson, E W, Beddoe-Stephens, B, Young, B, Kneller, B C, Lee, M K, Fortey, N J, Allen, P M, Branney, M J, Cooper, D C, Hirons, S, Kokelaar, B P, Marks, R J, McConnell, B J, Merritt, J W, Molyneux, S G, Petterson, M G, Roberts, B, Rundle, C C, Rushton, A W A, Scott, R W, Soper, N J and Stone, P. 2000. Geology of the Ambleside district. Memoir of the British Geological Survey, England and Wales, Sheet 38. 
Branney, M J, 1991. Eruption and depositional facies of the Whorneyside Tuff Formation, English Lake District: An exceptionally large-magnitude phreatoplinian eruption. Bulletin of the Geological Society of America, Vol.103, p.886-897. 
Branney, M J and Kokelaar B P, 1993. The Whorneyside Tuff Formation in the Central Fells. British Geological Survey Technical Report, WA/93/40. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E038 E029