The BGS Lexicon of Named Rock Units — Result Details

Rubha Ruadh Granite

Computer Code: RUBR Preferred Map Code: G
Status Code: Full
Age range: Palaeoproterozoic Era (AL) — Palaeoproterozoic Era (AL)
Lithological Description: Comprises granite, which is commonly foliated; granite gneiss and pegmatitic veins and pods. The granite is generally pink, coarse-grained and fairly homogenous, consisting of K-feldspar, plagioclase (oligoclase), quartz, minor biotite and accessory titanite and epidote. Intrusions belonging to this suite occur as WNW-ESE sheets in a zone along the Laxford Front, and have been variably deformed during the Laxfordian event at about 1750 Ma.
Definition of Lower Boundary: The Rubha Ruadh Granite is intrusive into the Inchard Gneiss.
Definition of Upper Boundary: N/a
Thickness: From 1m to about 200m
Geographical Limits: The granite and pegmatitic granite sheets of the Rubha Ruadh Granite Suite occur within the Lewisian Gneiss Complex in Sutherland. They are especially abundant in a 2km-wide WNW-ESE trending zone near the Laxford River, stretching from Rubha Ruadh in the WNW, to Loch Stack in the ESE. Further, smaller intrusions occur north of the Laxford River; e.g. near Rhiconich and Kinlochbervie. A body of Rubha Ruadh granite also occurs in the Moine Thrust Zone, south of Achfary. The suite occurs on Sheets 113 (Cape Wrath), 107E (Loch Glencoul), 108W (Ben Hee) and the Assynt Special Sheet.
Parent Unit: Lewisian Complex (L)
Previous Name(s): Laxfordian Granite Vein Complex (-1154)
Loch Stack Granite (-3651)
Rubha Ruadh Granites (-3652)
Rudha Ruadh Granite-Gneiss (-3653)
Laxfordian Granite Vein-Complex (Within Lewisian Complex) [Obsolete Name And Code: Use RUBR] (LAX)
Laxfordian (In Part Rhiconich Group) [Obsolete Name And Code: See ICGN And RUBR] (LLX)
Laxfordian (-2257)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  A 200m-thick granite sheet on the northern part of the Rubha Ruadh peninsula, north of Tarbet, northwest Sutherland. Beach, 1978. 
Reference(s):
Sutton, J and Watson, J V. 1951. The pre-Torridonian metamorphic history of the Loch Torridon and Scourie areas in the northwest Highlands, and its bearing on the chronological classification of the Lewisian. Quarterley Journal of the Geological Society of London, Vol.106, 241-307. 
Friend, C R L and Kinny, P D. 2001. A re-appraisal of the Lewisian Gneiss Complex: geochronological evidence for its tectonic assembly from disparate terranes in the Proterozoic. Contributions to Mineralogy and Petrology, Vol.142, 198-218. 
Beach, A. 1978. The Scourie-Laxford Region (Lewisian). In: The Lewisian and Torridonian rocks of north-west Scotland (editied by Barber, A J, Beach, A, Park, R G, Tarney, J and Stewart, A D) . Geologists' Association Guide, no.21, 14-26. 
Kinny, P D, Friend, C R L and Friend, J L G. 2005. Proposal for a terrane-based nomenclature for the Lewisian Complex of NW Scotland. Journal of the Geological Society of London, Vol.162, 175-186. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S107 S108 S113