The BGS Lexicon of Named Rock Units — Result Details

Dunnerdale Sandstone Formation

Computer Code: DNF Preferred Map Code: DnF
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Volcaniclastic sandstone, locally with volcaniclastic breccia; sequence coarsens upwards. Units within this contain ichnofossils [Johnson et al, 1994].
Definition of Lower Boundary: Base of volcaniclastic sandstone that rests unconformably on the Wallowbarrow Tuff Formation (andesitic tuff), Ulpha Andesite Formation (andesite lava) and Holehouse Mudstone Gill Formation (mudstone and sandstone). Andesite intrusions intervene locally.
Definition of Upper Boundary: Contact with overlying Lickle Formation (dacitic and rhyolitic tuff) and locally intervening intrusive basaltic andesite and andesite.
Thickness: 0 - 400m (excluding penecontemporaneous sills).
Geographical Limits: Duddon and Lickle valleys. Wallowbarrow Crag (SD 222 967) to Hotton (SD 204 902) and Lickle Valley (SD 230 920), Cumbria.
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Dunnerdale Formation (-3366)
Dunnerdale Tuffs (-4002)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Dunnerdale Fells, between Yew Pike (SD 203 925) and Croglinhurst (SD 212 898). 
Reference(s):
Mitchell, G H, 1956. (Undivided Lickle Rhyolites). The Borrowdale Volcanic Series of the Dunnerdale Fells, Lancashire. Liverpool and Manchester Geological Journal, Vol.1, p.428-449. 
Johnson, E W, Briggs, D E G, Suthren, R J, Wright, J L abd Tunnicliff, S P, 1994. Non-marine arthropod traces from the subaerial Ordovician Borrowdale Volcanic Group, English Lake District. Geological Magazine, Vol.131, 395-406. 
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. 
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