Loup of Fintry Lava Member

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Loup of Fintry Lava Member (LFLA), Campsie Block, Carboniferous, Midland Valley of Scotland[edit]

Loup of Fintry Lava Member is part of the Clyde Plateau Volcanic Formation.

Name[edit]

Previously named the Loup of Fintry Lavas (Forsyth et al., 1996)[1].

Lithology[edit]

The Loup of Fintry Lava Member consists of two lavas, separated by a thin bed of basaltic lapilli-tuff. The lower lava is a plagioclase-macrophyric trachybasalt (‘Markle’ type). The upper lava is a composite flow of similar overall composition, with intermingling of aphyric and feldspar-phyric components (NS 656 858). Other exposures of the member include plagioclase-macrophyric lava at the north-west end of Loch Carron (NS 673 856) and near the Spout of Dalbowie (NS 641 869).

Stratotype[edit]

The type area is the north-eastern Campsie Fells, north-east of Glasgow (NS 641 869 to NS 673 856) (Forsyth et al., 1996)[1]. A reference section is the Loup of Fintry (waterfall), in the Endrick Water, north-eastern Campsie Fells, north-east of Glasgow from (NS 6618 8617 to NS 6645 8612) (Craig, 1980)[2]. Here the full thickness of the member is evident.

Lower and upper boundaries[edit]

The lower (basal) plagioclase-macrophyric trachybasalt lava is conformable or disconformable on the underlying plagioclase-microphyric trachybasalt of the lower north Campsie lavas (Campsie Lava Member).

The upper composite lava of the Loup of Fintry Lava Member is overlain apparently conformably, or disconformably, by the upper north Campsie lavas (Campsie Lava Member). The lithological change is mostly to plagioclase-microphyric basalt (‘Jedburgh’ type), trachybasalt and basaltic-trachyandesite (mugearite).

Thickness[edit]

Nearly 30 m in the vicinity of the Loup of Fintry (NS 662 862).

Distribution and regional correlation[edit]

The member is restricted to the Campsie Block (Forsyth et al., 1996)[1] and specifically to the north-eastern Campsie Fells, north-east of Glasgow. These rocks crop out in small isolated areas, in the vicinity of the Loup of Fintry (NS 662 862), at the north-west end of Loch Carron (NS 673 856), and near the Spout of Dalbowie (NS 641 869).

Age[edit]

Mid Visean (Arundian to Asbian).

References[edit]

  1. 1.0 1.1 1.2 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)
  2. Craig, P M. 1980. The volcanic geology of the Campsie Fells area, Stirlingshire. Unpublished PhD Thesis, University of Lancaster