| Computer Code: |
TTA |
Preferred Map Code: |
Tta |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
White-weathered laminated and thinly bedded fine-grained volcaniclastic sandstone and siltstone |
| Definition of Lower Boundary: |
Taken at the sharp base of bedded volcaniclastic sedimentary rocks where these overlie pyroclastic rocks of the Lingmell Formation, and locally, the Airy's Bridge Tuff Formation and Scafell Dacite. The contact is gradational and arbitrary where the upper part of the Lingmell Formation has been reworked subaqueously |
| Definition of Upper Boundary: |
Defined by the base of overlying volcaniclastic rocks including the Cam Crags and Bell Crags members |
| Thickness: |
Up to 80m |
| Geographical Limits: |
Bell Crags, Thirlmere to Seathwaite (Borrowdale) Fell, and from Pike de Bield to the Langdale Pikes, Cumbria |
| Parent Unit: |
Seathwaite Fell Sandstone Formation (SET)
|
| Previous Name(s): |
Three Tarns Member [Obsolete Name and Code: Use TTA]
(-1241)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Pike O'Stickle to Harrison Stickle, Langdale, Cumbria Kneller and McConnell, 1993 |
| 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. |
| Kneller B C and McConnell, B J . 1993. The Seathwaite Fell Formation in the central Fells. British Geological Survey Technical Report WA/93/43 |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
