| Computer Code: |
LGLA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Asbian Substage (CR) |
| Lithological Description: |
Olivine-microphyric basalt lavas (Dalmeny type) with a few flows of clinopyroxene-olivine-microphyric basalt (Hillhouse type). Some clinopyroxene-olivine-macrophyric basalt (ankaramite or Craiglockhart type) intercalated in upper part of sequence. |
| Definition of Lower Boundary: |
The Largs Lava Member overlies the Noddsdale Volcaniclastic Member, as was proved in the Largs Borehole [NS 2158 5936]. |
| Definition of Upper Boundary: |
Lavas of the Largs Lava Member are more mafic than those of the overlying Greeto Lava Member with the boundary defined by the petrographic change from olivine-microphyric basalts (Dalmeny type) of the Largs Lava Member to the overlying plagioclase-phyric basalts and hawaiites (Jedburgh and Markle types) of the Greeto Lava Member. |
| Thickness: |
Up to 130 m. |
| Geographical Limits: |
Scarp slope east of Noddsdale Water from Largs [NS 20 59] to the Murishiel Fault [NS 23 65], east side of Knockencorsan Hill [NS 24 67]. South of Largs on the lower slopes of Douglas Park to the A760 road [NS 21 57]. |
| Parent Unit: |
Clyde Plateau Volcanic Formation (CPV)
|
| Previous Name(s): |
Largs Lavas [Obsolete Name and Code: Use LGLA]
(-1655)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Exposed in a major scarp on the east side of Noddsdale, to the south of the Muirshiel Fault, traced north along the east side of Noddsdale Water; on the east side of Knockencorsan Hill [NS 24 67] and in the Rotten Burn [NS 252 682]. |
| Reference(s): |
| Monro, S K. 1999. Geology of the Irvine District. Memoir of the British Geological Survey, Sheet 22W and part of 21E (Scotland). |
| 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). |
| Johnstone, G S. 1965. The volcanic rocks of the Misty Law-Knockside Hills district, Renfrewshire. Bulletin of the Geological Survey of Great Britain. No. 22. pp 53-64. |
| Richey, J E. 1928. The north Ayrshire sequence of Calciferous Sandstone volcanic rocks. Transactions of the Geological Society of Glasgow. 18. pp 247-255. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S030
|
