The BGS Lexicon of Named Rock Units — Result Details

Greenside Volcaniclastic Member

Computer Code: GNSV Preferred Map Code: notEntered
Status Code: Full
Age range: Arundian Substage (CJ) — Asbian Substage (CR)
Lithological Description: Volcaniclastic sedimentary rocks and tuffs. Tephra cones at Clachan of Campsie [NS 610 797] and Craigton [NS 525 770] cause unit to thicken to over 50m. West of Greenside [NS 452 747] up to 40m of lacustrine mudstones containing fossil fish and plant remains and thin coal seams are found near the top of the member.
Definition of Lower Boundary: The Loch Humphrey Borehole [NS 4592 7555] penetrated the lowest 20m of the Greenside Volcaniclastic Member which overlie lavas of the Carbeth Lava Member. There is an unconformity between the two units and elsewhere the Greenside Member rests directly upon the Auchineden Lava Member.
Definition of Upper Boundary: The Greenside Volcaniclastic Member is overlain by the lavas of the Cochno Lava Member
Thickness: Mostly 5-10m but up to 55m
Geographical Limits: The Greenside Volcaniclastic Member (usually 5-10m thick) is restricted to the Kilpatrick Hills, north-west of Glasgow. It forms a thin outcrop that runs north-east from Bowling [NS 454 737], through Greenside Reservoir [NS 474 755] and High Craigton [NS 525 766] to Blanefield [NS 555 795]. The member also crops out at the west end of Loch Humphrey [NS 451 762].
Parent Unit: Clyde Plateau Volcanic Formation (CPV)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The member is known from outcrop in the area around Greenside Reservoir, where 40m of lacustrine sedimentary rocks occur at the top of the member. Hall et al 1998 
Reference Section  The lower 20m of the Greenside Volcaniclastic Member is penetrated by the Loch Humphrey Borehole. Here it consists mainly of tuff. A geological log of the borehole is available in BGS borehole records. 
Reference(s):
Currie, A. 1866. On the occurrence of coal beds under the traps of the Bowling Hills. Transactions of the Geological Society of Glasgow, vol. 2, 149-151. 
Young, J. 1873. Notes on a section of strata containing beds of impure coal and plant remains showing structure at Glenarbuck near Bowling. Transactions of the Glasgow Geological Society, Vol 4, 123-128 
Scott, A.C., Galtier, J. and Clayton, G. 1984. Distribution of anatomically preserved floras in the Lower Carboniferous in Western Europe. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 75, 311-340. 
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). 
Young, J. 1873. On the occurrence of the remains of Carboniferous fishes in certain thin beds of indurated shale lying between sheets of trap, composing the Kilpatrick range of hills at Auchentorlie, near Bowling. Transactions of the Geological Society of Glasgow, Vol. 4, 77. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S030