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Tappetknowe Lava Member, Carboniferous, Midland Valley of Scotland

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== Tappetknowe Lava Member [http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=TKLA (TKLA)], Campsie Block, Carboniferous, Midland Valley of Scotland ==
Tappetknowe Lava Member is part of the [[Clyde Plateau Volcanic Formation]].
=== Name ===
Previously named the Tappetknowe Lavas (Forsyth et al., 1996)<ref name="Forsyth96">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).</ref>.

=== Lithology ===
The Tappetknowe Lava Member consists of several lavas with a total thickness of approximately 40 m. These include, near Tappetknowe (NS 750 815), microporphyritic basaltic-trachyandesite (mugearite) and trachybasalt and rare plagioclase-macrophyric trachybasalt (‘Markle’ type). The rocks are intensely faulted and jointed and deeply weathered, and there are no good sections, exposure being limited to small crags.

=== Stratotype ===
The type area is the central Kilsyth Hills, north of Glasgow (NS 7176 8064 to NS 7622 8197) (Forsyth et al., 1996)<ref name="Forsyth96"/>.

=== Lower and upper boundaries ===
The lower boundary is conformable or locally disconformable on the underlying [[Laird’s Loup Lava Member]], which comprises plagioclase-macrophyric trachybasalt, and is taken as the incoming of microporphyritic lavas (basaltic-trachyandesite to trachybasalt). The Tappetknowe Lava Member is overlain to the north-east of the Tak-ma-doon Fault (Craig, 1980)<ref name="Craig80">Craig, P M. 1980. The volcanic geology of the Campsie Fells area, Stirlingshire. Unpublished PhD Thesis, University of Lancaster</ref> by the [[Denny Muir Lava Member]]. The lithological change here is to massive, well-featured plagioclase-macrophyric basalt (of ‘Markle’ type), trachybasalt and rare basaltic-trachyandesite (mugearite).

To the south-west of the Tak-ma-doon Fault, the Tappetknowe Lava Member is overlain by the [[Kilsyth Hills Lava Member]], and the lithological change is mainly to plagioclase-macrophyric basalts and trachybasalts (hawaiites of ‘Markle’ type).

=== Thickness ===
Some 40 m.

=== Distribution and regional correlation ===
The member is restricted to the southern part of the Campsie Block (Forsyth et al., 1996)<ref name="Forsyth96"/> and specifically to the southern side of the central Kilsyth Hills, north-east of Glasgow. These rocks crop out in the escarpment on the southern side of the Kilsyth Hills, north-east of Kilsyth, from south of Tomtain (NS 7179 8062), eastward to the Tak-ma-doon Fault (Craig, 1980)<ref name="Craig80"/>, thence to the north and south of Doups (NS 7494 8138) and as far east as Tappetknowe (NS 7620 8196). Craig (1980)<ref name="Craig80"/> inferred that the source of the lavas was near to the present outcrop.

=== Age ===
Mid Visean (Arundian to Asbian).

== References ==
<references/>
[[Category:Carboniferous lithostratigraphical nomenclature]]

Tappetknowe Lava Member - Revision history

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Geosource>Volunteer 01: /* Tappetknowe Lava Member, Carboniferous, Midland Valley of Scotland */