Computer Code: |
BKB |
Preferred Map Code: |
Bkb |
Status Code: |
Full |
Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
Lithological Description: |
Dark grey to greenish grey basaltic and basaltic andesite lava flows; generally thin, porphyritic, simple aa-flows and intercalated bedded tuffs and volcaniclastic sandstones. |
Definition of Lower Boundary: |
Base of lowest basaltic andesite/basalt flow. Rests on Devoke Water Member in type area; farther east on undivided feldspar-phyric andesites of the Birker Fell Andesite Formation. |
Definition of Upper Boundary: |
Overlain by blocky, porphyritic andesite flows of Birker Fell Andesite Formation (undivided). |
Thickness: |
430 - >500m (upper boundary faulted in part). Absent to east of Devoke Water. |
Geographical Limits: |
Birkby Fell, Eskdale, Cumbria (SD 14 95) also Whincop, Eskdale (SD 180 993), Cumbria. |
Parent Unit: |
Birker Fell Andesite Formation (BFA)
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Previous Name(s): |
Birkby Fell Member [Obsolete Name and Code: Use BKB]
(-3219)
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Alternative Name(s): |
none recorded or not applicable
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Stratotypes: |
Type Area |
Crags of Birkby Fell and Woodend Height, southwest and south of Devoke Water, Cumbria. |
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. |
Petterson, M G, Beddoe-Stephens, B, Millward, D and Johnson, E W, 1992. A pre-caldera plateau-andesite field in the Borrowdale Volcanic Group of the English Lake District. Journal of the Geological Society, London, Vol. 149, 889-906. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E038
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