The BGS Lexicon of Named Rock Units — Result Details

Waberthwaite Tuff Formation

Computer Code: WB Preferred Map Code: Wb
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Acid andesitic to dacitic, welded lapilli-tuffs and tuffs; massive, poorly sorted, eutaxitic to parataxitic; intercalations of pyroclastic breccia.
Definition of Lower Boundary: At change from rhyolitic (of the Airy's Bridge Tuff Formation) to acid andesitic/dacitic welded tuffs; in part overlies andesites of the Birker Fell Andesite Formation, tuff and lapilli-tuff of the Whinny Bank Formation or the Po House Formation.
Definition of Upper Boundary: Defined by base of Duddon Hall Formation at the sharp change to andesitic bedded tuffs.
Thickness: Probably around 1100m. Not present east of Baskill Fault.
Geographical Limits: Whitfell, Burnmoor, Buck Barrow, Plough Fell, Waberthwaite, Millom Park, Cumbria. (SD 16 93; 14 90;16 90).
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Waberthwaite Formation (-4961)
Millom Park Formation [Obsolete Name: Part Of WB] (MPA)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Peg Crag, Kinmont Buck Barrow, Buck Barrow, Sele Botlam, (Corney Fell, Cumbria). 
Reference(s):
Firman, R G J, 1957. The Borrowdale Volcanic Series between Wastwater and Duddon Valley, Cumberland. Proceedings of the Yorkshire Geological Society, Vol.31, p.39-64. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E038 E048