The BGS Lexicon of Named Rock Units — Result Details

Loch Coire Formation

Computer Code: LOCE Preferred Map Code: notEntered
Status Code: Full
Age range: Tonian Period (AT) — Tonian Period (AT)
Lithological Description: Psammite, semipelite and pelite, interbanded, gneissose and migmatitic. Quartzo-feldspathic segregations common. Commonly garnetiferous. Some subunits are more psammitic; others more pelitic.
Definition of Lower Boundary: Lower boundary is mainly a structural boundary with the underlying Swordly Thrust. However, thin slivers of strained Lewisianoid gneiss (“Swordly Inlier”) suggest the Loch Coire Formation may be deposited unconformably upon Lewisianoid Gneiss.
Definition of Upper Boundary: Likely overlain by the Portskerra Formation, but any contact is highly sheared. In part cut by overlying Skinsdale Thrust.
Thickness: Strongly deformed, possibly > 1 km.
Geographical Limits: Northern Highlands, Sutherland. Restricted to the Swordly Nappe.
Parent Unit: Glenfinnan Group (GLEN)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
British Geological Survey. 2004. Badenloch. Scotland Sheet 109W. Bedrock. 1:50 000 Series. (Keyworth, Nottingham: British Geological Survey.) 
Strachan, R A, May, F and Barr, D, 1988. The Glenfinnan and Loch Eil Divisions of the Moine Assemblage. 32-45 IIV Winchester, J A (editor). Later Proterozoic stratigraphy of the Northern Atlantic regions (Glasgow and London: Blackie). 
Krabbendam, M. 2021. A stratigraphic framework for the early Neoproterozoic successions of the Northern Highlands of Scotland. UK Stratigraphic Framework Series. British Geological Survey Open Report, OR/21/072. 86pp. 
Strachan, R A, and Holdsworth, R. 1988. Basement-cover relationships and structure within the Moine rocks of central and southeast Sutherland. Journal of the Geological Society, Vol. 145, 23-36. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S094 S094 S102 S108 S109 S109 S103