The BGS Lexicon of Named Rock Units — Result Details

Allermuir Volcanic Member

Computer Code: ALMR Preferred Map Code: ALMR
Status Code: Full
Age range: Pridoli Epoch (SO) — Lochkovian Age (DO)
Lithological Description: Lowest flows are fine-grained microporphyritic pyroxene-andesites and olivine basalts, followed by feldspar phyric basalt and pyroxene andesites. Intercalations between flows include rhyolite and basic tuff, agglomerate and pebbly volcanic grit and tuff.
Definition of Lower Boundary: Conformable: in north east, where pyroxene andesites and olivine basalts overlie biotite rhyolite/dacite of Capelaw Volcanic Member. In south west where, olivine basalts and pyroxene andesites overlie rhyolites and thin lenses of conglomerate of the Bell's Hill Volcanic Member.
Definition of Upper Boundary: Conformable: where pyroxene andesites, olivine basalts and locally basic tuff and breccia are overlain by rhyolitic tuff and flow-banded rhyolite of the Caerketton Volcanic Member.
Thickness: At least 366m on Allermuir Hill.
Geographical Limits: Pentland Hills.
Parent Unit: Pentland Hills Volcanic Formation (PDH)
Previous Name(s): Allermuir Group [Obsolete Name And Code: Use ALMR] (ALG)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Lava flows forming trap features on north slope of Allermuir Hill between Todhole Knowe and summit 
Partial Type Section  At least seven distinct flows in craggy exposures on south ridge of East Kip. 
Partial Type Section  Intercalation of pebbly volcanic grit and tuff, 100m east of Loganlee Dam. 
Reference(s):
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). 
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. 
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.) 
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). 
Thirlwall, M F, 1988. Geochronology of Late Caledenian magmatism in northern Britain. Journal of the Geological Society, Vol.145, 951-967. 
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. 
Cameron, I B and Stephenson, D, 1985. British Regional Geology: The Midland Valley of Scotland (3rd Edition). (London: HMSO for British Geological Survey). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S032 S032