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): Whinneybank Tuffite (-1923)
Whinny Bank Formation (-1281)
Mottled Shale (-4670)
Alternative Name(s): none recorded or not applicable
Type Area  Whinney Bank, 1km west of The Green, Millom, South Cumbria. 
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(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 Unpublished Ph.D. thesis, University of Sheffield.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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used: