The BGS Lexicon of Named Rock Units — Result Details

Bad Step Tuff

Computer Code: BDP Preferred Map Code: Bdp
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: White to pink weathered rhyolitic, high-grade lava-like tuff; garnetiferous.
Definition of Lower Boundary: Base of rhyolitic, lava-like tuff. Unconformable on various units within the underlying Long Top Tuffs of Airy's Bridge Tuff Formation.
Definition of Upper Boundary: By overlying Crinkle Member of Airy's Bridge Tuff Formation.
Thickness: 40 - 400m
Geographical Limits: Borrowdale, Eskdale to Langdale. Hard Knott (NY 233 025) to White Gill Crag (NY 298 070), Cumbria.
Parent Unit: Crinkle Tuff Member (CRK)
Previous Name(s): Bad Step Tuff Member (-3831)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Bad Step near the summit of Crinkle Crags. 
Reference(s):
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, Kokelaar, B P and McConnell, B J. 1992. The Bad Step Tuff: a lava-like rheomorphic ignimbrite in a calc-alkaline piecemeal caldera, English Lake District. Bulletin Volcanology, Vol.54, 187-199. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E038 E029