The BGS Lexicon of Named Rock Units — Result Details

Whinny Bank Tuff Formation

Computer Code: WNB Preferred Map Code: WnB
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Interbedded succession of silty mudstone and andesitic lapilli-tuff; the proportion of andesitic lapilli increases up the succession. Much of the silty mudstone occurs as abraded pellets and accretionary lapilli, suggesting a pyroclastic origin.
Definition of Lower Boundary: Unconformity. Overlies erosion surface on Skiddaw Group.
Definition of Upper Boundary: Base of overlying Po House Formation (bedded tuff) or Waberthwaite Formation (dacitic tuff and lapilli-tuff).
Thickness: 0-300m
Geographical Limits: Whicham Valley:- between Broadgate (SD 180 867) and Lacra Bank (SD 145 815), Cumbria.
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Whinny Bank Formation (-1281)
Whinneybank Tuffite (-1923)
Mottled Shale (-4670)
Alternative Name(s): none recorded or not applicable
Type Area  Whinney Bank, 1km west of The Green, Millom, South Cumbria. 
British Geological Survey, 1994(a). Duddon Bridge and Hallthwaites, SD18NE, 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 Unpublished Ph.D. thesis, University of Sheffield. 
Green, J F N, 1913. The older Palaeozoic succession of the Dudden Estuary. London, 23pp. 
British Geological Survey, 1994(b). Millom Park, SD18SE, Solid and Drift, 1:10,000 (Keyworth, Nottingham, British Geological Survey). 
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: