| Computer Code: |
LTA |
Preferred Map Code: |
LTa |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Dacitic lapilli-tuff, typically lithic rich with both silicic and mafic clasts; interpreted as welded ignimbrite; locally with thin tuff and volcaniclastic sandstone interbeds. Component members are recognised in some areas. |
| Definition of Lower Boundary: |
Base of dacitic lapilli-tuff. Unconformably overlies erosion surface on top of Seathwaite Fell Sandstone Formation (volcaniclastic sandstone). Basaltic andesite and andesite sills may intervene locally. |
| Definition of Upper Boundary: |
Base of overlying formations: Esk Pike Formation (mudstone and siltstone) and, in the southeast of the district, Tarn Hows Tuff Formation (andesitic tuff and lapilli). |
| Thickness: |
170 to more than 800m |
| Geographical Limits: |
Lincomb Tarns - Scafell - Rossett Pike - High Raise, Easdale - Grasmere - Scandale - Wansfell - Ambleside - Skelwith Bridge - Yewdale - Coniston - Torver High Common, Brothers Water to Shap area, Cumbria. |
| Parent Unit: |
Borrowdale Volcanic Group (BVG)
|
| Previous Name(s): |
Lincomb Tarns Formation [Obsolete Name and Code: Use LTA]
(-4772)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Ridge from Glaramara to Allen Crags, along which lie the Lincomb Tarns (NY 241 093). |
| Reference Section |
Torver Beck. |
| Reference Section |
Threshthwaite Cove |
| Reference Section |
Pass of Dunmail Raise to Seat Sandal |
| 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. |
| Woodhall, D G, 1998. The geology of the Wythburn, Thirlmere and Fairfield areas of the north-east Lake District. British Geological Survey Technical Report WA/98/07. |
| Oliver, R L, 1961. The Borrowdale Volcanic and associated rocks of the Scafell area, English Lake District. Quarterly Journal of the Geological Society of London, Vol 117, p. 377-417 |
| McConnell, B J, 1993. The Lincomb Tarns and Esk Pike formations. British Geological Survey Technical Report, WA/93/44. |
| Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E038
E029
E030
E039
|
