The BGS Lexicon of Named Rock Units — Result Details

Strath Fionan Banded Semipelite Formation

Computer Code: SFBS Preferred Map Code: SFBS
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Rusty-weathering interbedded semipelite and pelite, with muscovite and biotite; cross-lamination and graded bedding well-preserved on 10-100mm scale; calcareous beds occur in places.
Definition of Lower Boundary: Sharp boundary from lineated quartzite with feldspathic laminae at top of Meall Dubh Quartzite Formation.
Definition of Upper Boundary: Transitional boundary to limestone of Strath Fionan Pale Limestone Formation.
Thickness: 0 - 60m in Sheet 55W; probably some tectonic thinning.
Geographical Limits: From Allt na Moine Buidhe [NN 7076 6110] to south bank of Allt Kinardochy [NN 7789 5727]. Not present east of the Loch Tay Fault, where its place is taken by the lower part of the Monzie Limestone and Schist Formation.
Parent Unit: Ballachulish Subgroup (DABH)
Previous Name(s): Monzie Limestone And Schist Formation (-4323)
Strath Fionan Banded Formation (-3028)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Allt Strath Fionan, c.1km west-north-west of Braes of Foss, along to line B-B' (Fig.4 of Treagus, J E. 2001). 
Reference(s):
Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). 
Harris, A L, Haselock, P J, Kennedy, M J and Mendum, J R, 1994. The Dalradian Supergroup in Scotland, Shetland and Ireland. 33-53 in Gibbons, W E and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, London, No.22. 
Stephenson, D and Gould, D , 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. 
Smith, R A and Harris, A L, 1976. The Ballachulish rocks of the Blair Atholl district. Scottish Journal of Geology, Vol.12, 153-157. 
Treagus, J E and King, G, 1978. A complete Lower Dalradian succession in the Schiehallion district, central Perthshire. Scottish Journal of Geology, Vol.14, 157-166. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S055