The BGS Lexicon of Named Rock Units — Result Details

Stonesty Tuff

Computer Code: STF Preferred Map Code: Stf
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: White-weathered, flinty, bedded and cross-bedded rhyodacitic tuff and accretionary lapilli-tuff
Definition of Lower Boundary: Taken at the base of bedded silicic tuff overlying andesitic tuff of the Whorneyside Formation; in places including in the reference section, there is an angular discordance at the base.
Definition of Upper Boundary: Defined by the overlying eutaxitic lapilli-tuff of the main part of the Long Top Tuff Member.
Thickness: Up to 6m
Geographical Limits: Cumbria. Thirlwell to Scafell and Stonesty Pike, central Lake District, occurring at the base of the Long Top Tuff Member except where the Oxendale Tuff is present.
Parent Unit: Long Top Tuff Member (LTT)
Previous Name(s): Stonesty Tuff Member (-1202)
Alternative Name(s): none recorded or not applicable
Reference Section  Stonesty Pike, 2.5km north of Cockley Beck Bridge, Upper Duddon Valley, Cumbria Branney et al., 1993 
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, Davis, N C, Kokalaar, B P and McConnell, B J. 1993. The Airy's Bridge Formation in the central Fells. British Geological Survey Technical Report WA/93/41 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable