| Computer Code: |
SLAV |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Asbian Substage (CR) |
| Lithological Description: |
The Slackgun Volcaniclastic Member consists predominantly of bedded tuff and/or volcaniclastic sedimentary rock, with weathered basalt lava (including 'bole') and a local olivine-microphyric basalt lava. |
| Definition of Lower Boundary: |
The Slackgun Volcaniclastic Member unconformably overlies the Skiddaw Lava Member. The lithological change is from transitional plagioclase-macrophyric to plagioclase-microphyric basalt lava or composite basalt lava to a dull red 'bole' reflecting prolonged weathering of the underlying lavas. |
| Definition of Upper Boundary: |
The Slackgun Volcaniclastic member is overlain, conformably or disconformably, by the Spout of Ballochleam Lava Member. The lithological change is from tuff or volcaniclastic sedimentary rock to plagioclase-microphyric basalt lava (of 'Jedburgh' type). |
| Thickness: |
0 to 80 m |
| Geographical Limits: |
The member is restricted to the northern Fintry Hills and the north-western Gargunnnock Hills, north-east of Glasgow. These rocks crop out from north-east of Spittalhill [NS 6521 8669] to the west-north-west to below Double Craigs [NS 631 875], north-north-west to below Stronend [NS 626 8955], and east-north-east to Black Craig [NS 6878 9241]. |
| Parent Unit: |
Clyde Plateau Volcanic Formation (CPV)
|
| Previous Name(s): |
Slackgun Interbasaltic Beds [Obsolete Name and Code: Use SLAV]
(-3682)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
In the northern, western and south-western Fintry Hills, and the north-western Gargunnock HIlls, north-east of Glasgow. Francis et al., 1970. |
| Reference Section |
Corrie-like scar, Slackgun, immediately north-west of Lees Hill, northern Fintry Hills, north-east of Glasgow. Francis et al., 1970. |
| Reference(s): |
| 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. |
| Francis, E H, Forsyth, I H, Read, W A and Armstrong, M. 1970. The geology of the Stirling district. Memoir of the Geological Survey of Great Britain, Sheet 39 (Scotland). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S039
|
