The BGS Lexicon of Named Rock Units — Result Details

Upper Lecket Hill Lava Member

Computer Code: ULHLA Preferred Map Code: notEntered
Status Code: Full
Age range: Arundian Substage (CJ) — Asbian Substage (CR)
Lithological Description: The Upper Lecket HIll Lava Member consists generally of relatively evolved lavas, including trachybasalt (hawaiite), basaltic-trachyandesite (mugearite), trachyte and rare plagioclase-microphyric basalt transitional to trachybasalt (of 'Jedburgh' type). The member is generally poorly exposed, but at least seven platy-jointed and rather slaggy lavas are present. North-east of the summit of Lecket Hill [NS 6445 8121], lapilli-tuffs and agglomerates predominate locally over lavas. Craig (1980) has inferred that the source of the member was the nearby Waterhead Centre ('Waterhead Central Volcanic Complex').
Definition of Lower Boundary: The basal basaltic-trachyandesite (mugearite) lava of the member is conformable or disconformable on underlying plagioclase-macrophyric trachybasalt (hawaiite) lava of the Boyd's Burn Lava Member.
Definition of Upper Boundary: The Upper Lecket Hill Lava Member is overlain apparently conformably or disconformably by the Kilsyth Hills Lava Member, which has a similar geographical distribution. The lithological change is to plagioclase-macrophyric transitional to plagioclase-microphyric basalt and trachybasalt (hawaiite) lavas (of 'Markle' type transitional to 'Jedburgh' type).
Thickness: 65 m
Geographical Limits: The member is restricted to the Campsie Block and has a limited geographical extent, (reflecting the proximal character of the lava flows) in the eastern Campsie Fells and westernmost Kilsyth HIlls, north of Glasgow.
Parent Unit: Clyde Plateau Volcanic Formation (CPV)
Previous Name(s): Upper Lecket Hiil Lavas (-4383)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The eastern Campsie Fells, and westernmost Kilsyth HIlls, north of Glasgow Forsyth et al, 1996, after Craig, 1980 
Reference Section  Back Burn 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 Unpublished PhD thesis, University of Lancaster. 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:
S030