Stronend Volcaniclastic Member

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Stronend Volcaniclastic Member (STRV), Fintry-Touch Block, Carboniferous, Midland Valley of Scotland[edit]

Stronend Volcaniclastic Member is part of the Clyde Plateau Volcanic Formation.

Name[edit]

Previously known as the Stronend Interbasaltic Beds (see Francis et al., 1970)[1].

Lithology[edit]

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.

Stratotype[edit]

The type area is in the western Fintry Hills, north-east of Glasgow (NS 6322 8808 to NS 6274 8953) (Francis et al., 1970)[1]. A reference section is 0.5 km south of Stronend summit, western Fintry Hills (NS 6288 8885) (Francis et al., 1970)[1]. Here more than 1.5 m of bole lying near the base of the member is exposed.

Lower and upper boundaries[edit]

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.

Thickness[edit]

Uncertain. Francis et al. (1970)[1] 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[edit]

The member is restricted to the Fintry–Touch Block (Francis et al., 1970)[1] 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).

Age[edit]

Mid Visean (Arundian to Asbian).

References[edit]

  1. 1.0 1.1 1.2 1.3 1.4 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)