| Computer Code: |
LDDMI |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Early Devonian Epoch (DL)
— Early Devonian Epoch (DL) |
| Lithological Description: |
Quartz feldspar-phyric microgranite, plagioclase-biotite-phyric microgranodiorite, and rhyolite dykes and minor intrusions. Examples of these dykes in the Scafell area have the following radiometric ages: 393 +/- 9 Ma, 392 +/- 4 Ma ( Rb-Sr whole rock) (Al Jawadi, 1987). |
| Definition of Lower Boundary: |
Includes all dykes, sills and other minor intrusions in the Lake District of proved and inferred Lower Devonian age. |
| Definition of Upper Boundary: |
Not defined. |
| Thickness: |
Not defined. |
| Geographical Limits: |
Within the Lake District Lower Palaeozoic inlier of Cumbria, and in the Cross Fell Inlier. |
| Parent Unit: |
Caledonian Supersuite (CIGSS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Duddon valley, south from Troutal to Logan Beck: various SW-trending dykes of porphyritic microgranite exposed in the river and stream banks. Millward and 22 others 2000 |
| Type Area |
Kirk Fell to Great Bank, Wasdale: a major dyke of quartz-feldspar-phyric microgranite. Millward and 22 others 2000. |
| Reference(s): |
| Al Jawadi, A E. 1987. Minor igneous intrusions of the Lake District; geochronology, geochemistry and petrology. PhD thesis, University of Newcastle. |
| Millward, D. 2002. Early Palaeozoic magmatism in the English Lake District. Proceedings of the Yorkshire Geological Society, Vol. 54, Part 2, 65-93. |
| 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. |
| Soper, N J and Kneller, B C. 1990. Cleaved microgranite dykes of the Shap swarm in the Silurian of NW England. Geological Journal, Vol.25, 161-170. |
| Morrison, J. 1918. The Shap minor intrusions. Quarterly Journal of the Geological Society, London. Vol.74, 116-144. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E037
E029
E048
E039
E038
E047
E030
E024
E003
|
