Stronend Volcaniclastic Member
Stronend Volcaniclastic Member (STRV), Fintry-Touch Block, Carboniferous, Midland Valley of Scotland
Stronend Volcaniclastic Member is part of the Clyde Plateau Volcanic Formation.
Previously known as the Stronend Interbasaltic Beds (see Francis et al., 1970).
The Stronend Volcaniclastic Member consists predominantly of volcaniclastic sedimentary rocks and possible tuff, with weathered basalt lava (including bole). It weathers back to form a prominent shelf in the escarpment on the western side of the Fintry Hills.
The type area is in the western Fintry Hills, north-east of Glasgow (NS 6322 8808 to NS 6274 8953) (Francis et al., 1970). A reference section is 0.5 km south of Stronend summit, western Fintry Hills (NS 6288 8885) (Francis et al., 1970). Here more than 1.5 m of bole lying near the base of the member is exposed.
Lower and upper boundaries
Weathered basalt (bole) at the base of the member is conformable or disconformable on plagioclase-microphyric basalt lava of the Spout of Ballochleam Lava Member within which the Stronend Volcaniclastic Member is interdigitated.
Volcaniclastic rocks of the Stronend Volcaniclastic Member are overlain by plagioclase-microphyric basalt lava of the Spout of Ballochleam Lava Member, within which the Stronend Volcaniclastic Member is interdigitated.
Uncertain. Francis et al. (1970) stated that the member seems to be relatively thin and local. At Stronend summit (NS 6288 8885) more than 1.5 m of bole is exposed, lying near the base of the member. In a tributary of Cammal Burn (NS 6399 8764) more than 2.7 m of bole crops out, probably at the top of the member.
Distribution and regional correlation
The member is restricted to the Fintry–Touch Block (Francis et al., 1970) and specifically to the western Fintry Hills, north-east of Glasgow. These rocks crop out out in a restricted area from the western side of Stronend (NS 6274 8953) to the south-south-east, to north of Double Craig (NS 6322 8808).
Mid Visean (Arundian to Asbian).
- 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)