| Computer Code: |
LHLA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Asbian Substage (CR) |
| Lithological Description: |
The Langhill Lava Member consists of four lavas of typically fine-grained, platy-jointed basaltic-trachyandesite (mugearite) with a total thickness of 35 m. The only exposures are in the River Carron [NS 773 845], 500 m north-east of Langhill. The lowest lava is relatively coarse grained and is about 15 m thick, with well-developed columnar jointing. The other lavas are very fine grained and intensely jointed. One at least of these has an autobrecciated base, consisting of buckled and disrupted tabular blocks of the lava. |
| Definition of Lower Boundary: |
The member overlies plagioclase-microphyric trachybasalt of the Campsie Lava Member, but the nature of the contact is unknown. |
| Definition of Upper Boundary: |
The Langhill Lava Member is overlain by the Gargunnock Hills Lava Member, but the nature of the contact is unknown. The lithological change is to mostly plagioclase-macrophyric basalt or hawaiite (of 'Markle type') with some microporphyritic basalts (of 'Jedburgh' and 'Dalmeny' types). |
| Thickness: |
35 m |
| Geographical Limits: |
The member is restricted to the Campsie Block (Forsyth et al., 1996) and specifically to the eastern part of the Kilsyth Hills, north-east of Glasgow. These rocks mostly crop out on the northern side of the Carron Glen (between [NS 7750 8442] and [NS 7616 8539]), with the outcrop extending locally to the base of the valley [NS 7739 8450] and onto the southern side [NS 7709 6446]. |
| Parent Unit: |
Clyde Plateau Volcanic Formation (CPV)
|
| Previous Name(s): |
Langhill Lavas [Obsolete Name and Code: Use LHLA]
(-2902)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
The eastern part of the Kilsyth Hills, north-east of Glasgow. Forsyth et al., 1996, after Craig, 1980. |
| Reference Section |
River Carron, eastern Kilsyth Hills, north-east of Glasgow. Craig, 1980. |
| Reference(s): |
| Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. |
| 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 Unpublished PhD thesis, University of Lancaster.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 Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S031
|
