The BGS Lexicon of Named Rock Units — Result Details
Crinkle Tuff Member
| Computer Code: | CRK | Preferred Map Code: | Crk |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Caradoc Series (O4) — Caradoc Series (O4) | ||
| Lithological Description: | Rhyolitic tuffs, lapilli-tuffs and pyroclastic breccias that are mostly very densely welded; rocks are conspicuously garnetiferous. Widespread intercalations of laminated rhyolitic tuff. | ||
| Definition of Lower Boundary: | Base of high-grade rhyolitic pyroclastic rocks. Locally unconformable on older parts of Airy's Bridge Tuff Formation. | ||
| Definition of Upper Boundary: | Contact with overlying formations comprising a mixed succession of bedded pyroclastic rocks and volcaniclastic sandstones, containing lavas and sills of andesite and basaltic andesite. | ||
| Thickness: | 0 - 700m | ||
| Geographical Limits: | Crinkle Crags to Scafell, Great Gable, Base Broan and Bell Crag. Yewbarrow, Illgill Head, Cumbria. | ||
| Parent Unit: | Airy's Bridge Tuff Formation (AIB) | ||
| Previous Name(s): | Crinkle Member [Obsolete Name and Code: Use CRK]
(-4568)
Crinkle Tuffs [Obsolete Name and Code: Use CRK] (-3956) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Summit of Crinkle Crags between Long Top and Shelter 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, 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 | |||
| 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 | |||