The BGS Lexicon of Named Rock Units — Result Details

Creag Na Sanais Semipelite Formation

Computer Code: CNSS Preferred Map Code: notEntered
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Dark grey gneissose semipelite composed mainly of muscovite, biotite, quartz, some plagioclase and garnet, with local thin fine-grained biotite-rich and quartoze psammite interbeds.
Definition of Lower Boundary: Top of the predominantly psammite beds belonging to the Creag Dhubh Psammite Formation, below the predominantly semipelitic beds of the Creag na Sanais Semipelitic Formation.
Definition of Upper Boundary: Base of the predominantly psammitic Allt nam Biorag Member, Fara Psammite Formation, above the predominantly semipelitic beds of the Creag na Sanais Semipelite Formation.
Thickness: 100 - 200m
Geographical Limits: South of Newtonmore, west of Crubenmore on Sheet 64W
Parent Unit: Glen Spean Subgroup (GRGS)
Previous Name(s): Part Of The 'Schists' Within The Moine Series (-3315)
Alternative Name(s): none recorded or not applicable
Type Section  Outcrops south of Creag na Sanais Leslie, A G. et al., BGS Internal Report IR/03/048 
Leslie, A G, Krabbendam, M and Smith, R A, 2003. Progress Report on the Geology of 1:50 k Sheet 64W (Newtonmore) British Geological Survey Internal Report, IR/03/048. 23pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable