The BGS Lexicon of Named Rock Units — Result Details

Carnethy Volcanic Member

Computer Code: CAHI Preferred Map Code: CAHI
Status Code: Full
Age range: Pridoli Epoch (SO) — Lochkovian Age (DO)
Lithological Description: Feldspar-phyric and fine-grained microporphyritic basalts and andesites. Flows have amygdaloidal tops and bases.
Definition of Lower Boundary: Conformable: where pale lilac or pink trachytes and andesites of the Woodhouselee Volcanic Member are overlain by feldspar-phyric and fine-grained microporphyritic basalts and andesites.
Definition of Upper Boundary: Not seen: faulted against Carboniferous strata to the east.
Thickness: Approximately 200m seen
Geographical Limits: Pentland Hills.
Parent Unit: Pentland Hills Volcanic Formation (PDH)
Previous Name(s): Carnethy and Hillend Volcanic Formation [Obsolete Name and Code: Use CAHI] (-2044)
Carnethy and Hillend Group [Obsolete Name and Code: Use CAHI] (-2043)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Carnethy Hill and Hillend, South Edinburgh, Midlothian. 
Type Section  Extensive exposures of porphyritic olivine-basalt and pyroxene andesite on east slope of Caerketton Hill and Hillend Hill. 
Reference Section  Exposures of the distinctive 'Carnethy porphry' (Mykura, 1960, p.142) in several disused quarries on the south east slopes of Carnethy Hill. Olivine-basalt with sub-parallel phenocrysts of tabular labradorite up to 26mm long. 
Reference(s):
Cameron, I B and Stephenson, D, 1985. British Regional Geology: The Midland Valley of Scotland (3rd Edition). (London: HMSO for British Geological Survey). 
Mykura, W, 1960. The Lower Old Red Sandstone igneous rocks of the Pentland Hills. Bulletin of the Geological Survey of Great Britain, No.16, 131-155. 
Peach, B N, Clough, C T, Hinxman, L W, Grant Wilson, J S, Crampton, C B, Maufe, H B and Bailey, E B, 1910. The geology of the Neighbourhood of Edinburgh (2nd edition). Memoir of the Geological Survey of Scotland, Sheet 32 (Scotland). 
MacGregor, A G. 1935. Guide to Geological Excursion in and around Edinburgh. Geological Survey Centenary. H.M.S.O. Field Trip Guides. 
Flett, J S. 1914. The geology of the district around Edinburgh. Edited by Monckton, H W. Proceedings of the Geologists' Association, Vol.25, Part 1, 1-18 and p.40 (Bibliography). London:Stanford 
Geikie, A, 1897. The Ancient Volcanoes of Great Britain. Vol.1, 317-325. (London: Macmillan). 
Howell, H H and Geikie, A, 1861. The Geology of the neighbourhood of Edinburgh (1st edition). Memoir of the Geological Survey, Scotland. 
Mykura, W, 1986. Pentland Hills. 161-173 in Lothian Geology. An Excursion Guide. McAdam, A D and Clarkson, E N K (editors). (Edinburgh: Scottish Academic Press.) 
Thirlwall, M F, 1988. Geochronology of Late Caledenian magmatism in northern Britain. Journal of the Geological Society, Vol.145, 951-967. 
Mitchell, G H. 1962. The geology of the neighbourhood of Edinburgh. (Explanation of Sheet 32) Third Edition. (Reprinted 1980). Memoir of the Geological Survey of Great Britain (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S032 S032