The BGS Lexicon of Named Rock Units — Result Details

Craigdouffie Lava Member

Computer Code: CDLA Preferred Map Code: notEntered
Status Code: Full
Age range: Arundian Substage (CJ) — Asbian Substage (CR)
Lithological Description: The Craigdouffie Lava Member consists of a sequence of at least four lavas, comprising alternating plagioclase-macrophyric basalt or trachybasalt (basalt to hawaiite of 'Markle' type) and aphyric basaltic-trachyandesite (mugearite), all with proximal-facies characteristics. The source is probably an undetected vent in the immediate vicinity (Craig, 1980).
Definition of Lower Boundary: The base is faulted and unseen
Definition of Upper Boundary: The Craigdouffie Lava Member is overlain by poorly exposed volcaniclastic sedimentary rocks of the Kirkwood Formation of the Strachclyde Group. The lithological change is from basalt or trachybasalt to tuffaceous mudstones and tuffs but the nature of the contact is not known.
Thickness: More than 15 m, base not seen
Geographical Limits: The member is restricted to a small area adjacent to the south side of the Campsie Fault and adjacent to the north-east side of the Tak-ma-doon Fault, in the south-eastern Kilsyth Hills, north-east of Glasgow.
Parent Unit: Clyde Plateau Volcanic Formation (CPV)
Previous Name(s): Craigdouffie Lavas (-759)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Craigdouffie Burn, south-eastern Kilsyth Hills, north-east of Glasgow Craig, 1980 
Type Area  South-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 Unpublished PhD thesis, University of Lancaster. 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