Greenside Volcaniclastic Member

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Greenside Volcaniclastic Member (GNSV), Kilpatrick Hills, Carboniferous, Midland Valley of Scotland[edit]

The Greenside Volcaniclastic Member is part of the Clyde Plateau Volcanic Formation.

Name[edit]

The unit is known from outcrops in the area around Greenside Reservoir (see Hall et al., 1998)[1].

Lithology[edit]

Volcaniclastic sedimentary rocks, tuff and agglomerate, organic and clastic sedimentary rocks. West of Greenside, lacustrine mudstones containing fossil fish and well-preserved plant remains and thin coal seams occur near the top of the member.

Stratotype[edit]

The unit is known from outcrops in its type area around Greenside Reservoir (NS 475 755) (see Hall et al., 1998)[1]. A reference section of the lower 21.35 m of the Greenside Volcaniclastic Member was penetrated by the Loch Humphrey Borehole (BGS Registration Number NS47NE/1) (NS 4582 7555) (from 0–21.35 m depth). In the borehole it consists mainly of tuff.

Lower and upper boundaries[edit]

The Loch Humphrey Borehole (see above) penetrated the lowest 21.35 m of the Greenside Volcaniclastic Member, which overlies the lavas and pyroclastic rock of the Carbeth Lava Member. There is an unconformity between the two units and elsewhere the Greenside Volcaniclastic Member rests directly upon the Auchineden Lava Member.

The Greenside Volcaniclastic Member is overlain by the lavas of the Cochno Lava Member.

Thickness[edit]

Between 0.5 and 55 m, but usually 5–10 m. Cones of pyroclastic rock at Clachan of Campsie (NS 610 797) and Craigton (NS 525 770) cause the member to thicken to over 50 m.

Distribution and regional correlation[edit]

The Greenside Volcaniclastic Member (usually 5–10 m thick) forms a thin outcrop in the Kilpatrick Hills that runs north-east from Bowling (NN 454 370), through Greenside Reservoir (NS 474 755) and High Craigton (NS 525 766) to Blanefield (NS 555 795). The unit also crops out at the west end of Loch Humphrey (NS 451 762).

Age[edit]

Mid Visean (Arundian to Asbian).

References[edit]

  1. 1.0 1.1 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)