| Computer Code: |
GLLA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Asbian Substage (CR) |
| Lithological Description: |
Distinctive olivine-bearing plagioclase-macrophyric basalts (Markle type). Characterised by lava flows with abundant, platy phenocrysts of plagioclase up to 2 5mm long and microphenocrysts of red-brown olivine. A massive flow of plagioclase-microphyric basalt (Jedburgh type) forms the base of the member at Linn Well [2475 6605]. Lavas are interbedded with volcaniclastic sedimentary rocks at the base of the member. |
| Definition of Lower Boundary: |
The Gleniffer Lava Member is underlain by the sedimentary rocks of the Glenburn Volcaniclastic Member to the north and east of Brownside Braes [2485 6605]. |
| Definition of Upper Boundary: |
The Gleniffer Lava Member is overlain and may be cut out or overlapped, by the mafic basalts of the Sergeantlaw Lava Member around Sergeantlaw [2455 6597] and to the east of Middleton [2445 6579], and to the west of Barcraigs Reservoir [239 657] and Walls Hill [241 659]. The Gleniffer Lava Member may thin to the east . |
| Thickness: |
none recorded or not applicable
|
| Geographical Limits: |
The Gleniffer Lava Member crops out in the Beith - Barrhead Hills, to the east of Barcraigs Reservoir [NS 39 57] and is faulted against the Kirkwood Formation and Lawmuir Formation in the north, to the north of High Burnside [NS 42 60]. It extends eastwards through Gleniffer Braes [NS 450 607] to Brownside Braes [NS 485 605]. To the south the unit is faulted against the Upper Limestone Formation at Loch Libo [NS 465 556] and the Limestone Coal Formation by the Lugton Water Fault. |
| Parent Unit: |
Clyde Plateau Volcanic Formation (CPV)
|
| Previous Name(s): |
'Gleniffer Lavas' [Obsolete Name and Code: Use GLLA]
(-2207)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
The Gleniffer Lava Member crops out in a prominent scarp along the north side of Gleniffer Braes to Brownside Braes, Hall et al. 1998 |
| Reference(s): |
| Paterson, I B, Hall, I H S and Stephenson, D. 1990. Geology of the Greenock district: Memoir for 1:50000 geological sheet 30W and part of sheet 29E (Scotland). |
| Monro, S K. 1999. Geology of the Irvine District. Memoir of the British Geological Survey, Sheet 22W and part of 21E (Scotland). |
| 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. 165 pp. |
| 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). |
| Richey, J E, Anderson, E M, and Macgregor, A G. 1930.The geology of north Ayreshire. Memoir of the Geological Survey of Great Britain. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S030
S030
S022
S022
|
