| Computer Code: |
CTLA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Asbian Substage (CR) |
| Lithological Description: |
The Craigentimpin Lava Member consists of plagioclase-macrophyric basalt to trachybasalt (hawaiite) (of 'Markle' type) with particularly large platy phenocrysts of calcic labradorite. The maximum thickness of the member, about 30 m, is developed in the Sloughmuclock area [NS 627 795], where two lavas are present. Elsewhere, it generally consists of only one lava that thins out entirely farther west.The orientation of the feldspar phenocrysts suggests that the source of the lava was the Waterhead Centre ('Waterhead Central Volcanic Complex') (Whyte and MacDonald, 1974). |
| Definition of Lower Boundary: |
The base is conformable or disconformable on the underlying plagioclase-microphyric trachybasalt lava of lower north Campsie lavas (Campsie Lava Member) in the north of its outcrop, and by plagioclase-microphyric trachybasalt lavas of the lower north and south Campsie lavas (Campsie Lava Member) in the south of its outcrop. |
| Definition of Upper Boundary: |
The Craigentimpin Lava Member is overlain with apparent conformity by the upper north and upper south Campsie lavas (Campsie Lava Member). The lithological change is to mostly plagioclase-microphyric basalt to trachybasalt (hawaiite) lavas (of 'Jedburgh' type). |
| Thickness: |
0 to 30 m |
| Geographical Limits: |
The member is restricted to the central and eastern Campsie Fells, north of Glasgow. |
| Parent Unit: |
Clyde Plateau Volcanic Formation (CPV)
|
| Previous Name(s): |
Craigentimpin Lavas [Obsolete Name and Code: Use CTLA]
(-2130)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Central Campsie Fells, north of Glasgow. Forsyth et al., 1996, after Craig, 1980. |
| Reference Section |
Alvain Burn, Craig, 1980. |
| Reference(s): |
| Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). |
| Hall, I H S, Browne, M A E and Forsyth, I H. 1998. Geology of the Glasgow district. Memoir of the British Geological Survey, Sheet 30E (Scotland). |
| Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. |
| Whyte, D and MacDonald, J G. 1975. The Lower Carboniferous rocks of the Campsie-Kilpatrick area. Scottish Journal of Geology, Vol. 11, 364-365. |
| Craig, P M. 1980. The Volcanic Geology of the Campsie Fells area, Stirlingshire. Unpublished PhD thesis, University of Lancaster. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S031
S030
|
