The BGS Lexicon of Named Rock Units — Result Details

Bonaly Volcanic Member

Computer Code: BNY Preferred Map Code: BNY
Status Code: Full
Age range: Pridoli Epoch (SO) — Lochkovian Age (DO)
Lithological Description: Lowest flows are feldspar phyric andesites and upper flows are fine-grained andesites. Feldspar phyric olivine basalts and pyroxene-andesites, trachybasalts, rhyolites and trachytes are also present.
Definition of Lower Boundary: Not exposed. Faulted against Ballagan Formation to the north and overlain by Kinnesswood Formation to west.
Definition of Upper Boundary: Unconformable: upper flows of andesites and basalts overlain by conglomerates and grits of Greywacke Conglomerate Formation and rhyolite of Bell's Hill Volcanic Member.
Thickness: 350m maximum
Geographical Limits: Pentland Hills.
Parent Unit: Pentland Hills Volcanic Formation (PDH)
Previous Name(s): Beds C, E [Obsolete Name and Code: Use BNY] (-1372)
Bonaly Volcanic Formation [Obsolete Name and Code: Use BNY] (-1373)
Bonaly Group [Obsolete Name And Code: Use BNY] (BOG)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Crags forming north slope of White Hill. Feldspar-phyric andesites and fine grained andesites. 
Type Section  Dean Burn, draining north west slopes of Capelaw Hill. Feldspar-phyric olivine basalt and pyroxene andesite, interbedded trachybasalt, and thin rhyolites. 
Reference(s):
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. 
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). 
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. 
Browne, M A E, Smith, R A and Aitken, A M. 2001. A lithostratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen. Version 3. British Geological Survey Research Report RR/01/04. 
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