The BGS Lexicon of Named Rock Units — Result Details

Denny Muir Lava Member

Computer Code: DMLA Preferred Map Code: notEntered
Status Code: Full
Age range: Arundian Substage (CJ) — Asbian Substage (CR)
Lithological Description: The Denny Muir Lava Member consists mostly of massive lavas of plagioclase-macrophyric basalt or trachybasalt (hawaiite) (of 'Markle' type), trachybasalt and rare basaltic trachyandesite (mugearite). The lavas are essentially continuous with those of the Kilsyth Hills Lava Member which lie to the west of the Tak-ma-doon Fault. The basal lava east of Darrach Hill [NS 754 827] is composite, with mingled components of plagioclase-macrophyric and plagioclase-microphyric basalt or trachybasalt (of 'Markle' and 'Jedburgh' types respectively). The lavas were thought by Craig (1980) to have been derived from the Waterhead Centre (`Waterhead Central Volcanic Complex?).
Definition of Lower Boundary: To the north and east, the base, locally a composite lava, is conformable or disconformable on the underlying plagioclase-microphyric trachybasalt lavas of the upper north and upper south Campsie lavas (Campsie Lava Member) but towards the south-west, where these lavas are absent, the member rests directly on plagioclase-microphyric basaltic trachyandesite and/or trachybasalt, of the Tappetknowe Lava Member, suggesting that the boundary is an unconformity.
Definition of Upper Boundary: The Denny Muir Lava Member occupies summit areas across its outcrop and the top of the member has been eroded.
Thickness: Up to 85 m
Geographical Limits: The member is restricted to the Campsie Block and specifically to the eastern Kilsyth Fells east of the Tak-ma-doon Fault [NS 7396 8109 to 7300 8196], north-east of Glasgow.
Parent Unit: Clyde Plateau Volcanic Formation (CPV)
Previous Name(s): Denny Muir Lavas (-2760)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Crags west of Birns, eastern Kilsyth Hills, north-east of Glasgow Craig, 1980 
Type Area  Eastern Kilsyth Hills, north-east of Glasgow Forsyth et al, 1996, after Craig, 1980 
Reference(s):
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Aidrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). 
Craig, P.M. 1980 The Volcanic Geology of the Campsie Fells area, Stirlingshire. Unpublished PhD thesis, University of Lancaster. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S031