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:
Reference Section  Back Burn Craig, 1980 
Type Area  The eastern Campsie Fells, and westernmost Kilsyth HIlls, north of Glasgow Forsyth et al, 1996, after Craig, 1980 
Reference(s):
Craig, P.M. 1980 The Volcanic Geology of the Campsie Fells area, Stirlingshire. Unpublished PhD thesis, University of Lancaster. 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S030