Auchineden Lava Member

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Auchineden Lava Member (ACLA), Kilpatrick Hills, Carboniferous, Midland Valley of Scotland[edit]

The Auchineden Lava Member is part of the Clyde Plateau Volcanic Formation.

Name[edit]

Previously known as the Auchineden Lavas (Hall et al., 1998)[1].

Lithology[edit]

The member comprises plagioclase-microphyric basalts (‘Jedburgh’ type), with some mugearites and interbedded cone-facies tuffs. On the Langs Craigs (NS 430 760) there is an olivine-clinopyroxene-macrophyric basanite lava (‘Craiglockhart’ type).

Stratotype[edit]

The member is well exposed in its type area on the west flank of Auchineden Hill (NS 493 805). A reference section was encountered in the Loch Humphrey Borehole (BGS Registration Number NS47NE/1) (NS 4582 7555). Here it is 45 m thick and lies below the Carbeth Lava Member and above the Burncrooks Volcaniclastic Member. It consists of mainly aphyric and microporphyritic lavas of ‘Jedburgh’ type with a flow of ‘Markle’ type. A geological description of the core is available.

Lower and upper boundaries[edit]

In the area around Saughen Braes (NS 462 783) the Auchineden Lava Member is underlain by, and interdigitates with, the Saughen Braes Lava Member. In the north and west of the Kilpatrick Hills the Auchineden Lava Member is directly underlain by the Burncrooks Volcaniclastic Member. The Auchineden Lava Member is overlain by the plagioclase-macrophyric lavas of the Carbeth Lava Member.

Thickness[edit]

Between 0 and 100 m, very variable.

Distribution and regional correlation[edit]

Kilpatrick Hills: well exposed on the west flank of Auchineden Hill (NS 493 805). The Auchineden Lava Member thins out towards the north-east and is absent at Arlehaven (NS 535 802). West of Burncrooks (NS 468 785) the member interdigitates with and overlies the Saughen Braes Lava Member and becomes the only member present farther west on Langs Craigs (NS 430 760).

Age[edit]

Mid Visean (Arundian to Asbian).

References[edit]

  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)

References[edit]