The BGS Lexicon of Named Rock Units — Result Details

Allermuir Group [Obsolete Name And Code: Use ALMR]

Computer Code: ALG Preferred Map Code: notEntered
Status Code: Index Level
Age range: Devonian Period (D) — Devonian Period (D)
Lithological Description: Basic andesites and olivine-basalts with intercalations of grits, basic tuffs and breccias; local rhyolite and rhyolitic tuff.
Definition of Lower Boundary: Drawn at the base of the Allermuir Group where fine-grained, red-weathered microporphyritic pyroxene-andesites and olivine-basalts rest conformably upon dacite or feldspar-phyric rhyolite of the Capelaw Acid Group.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Allermuir Group where fine- grained, relatively unweathered microporphyritic, augite and hypersthene-andesites are overlain by acid tuff of the Caerketton Group.
Thickness: Approx. 400 metres.
Geographical Limits: From Allermuir Hill in the vicinity of Swanston to Monk's Burn in the Pentland Hills on the southern outskirts of Edinburgh.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Allermuir Volcanic Member
Stratotypes:
Type Area  The Pentland Hills from Swanston to Monk's Burn. 
Reference(s):
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. 
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). 
Cockburn, A M, 1952. Minor Intrusions of the Pentland Hills. Transactions of Edinburgh Geological Society, Vol.15, 84-99. 
Peach, B N, Horne, J, Gibson, W, Anderson, E M, Grabham, G W and Flett, J S, 1910. The geology of the neighbourhood of Edinburgh. (Sheet 32, with part of Sheet 31). Memoir of the Geological Survey of Great Britain (Scotland), p.20 and 25. 
Cockburn, A M, 1956. Notes on the geology of the eastern slopes of Blackford Hill, Edinburgh. Transactions of the Edinburgh Geological Society, Vol.16, 307-312. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable