The BGS Lexicon of Named Rock Units — Result Details

Ben Wyvis Pelite Formation

Computer Code: BWYP Preferred Map Code: SYMB
Status Code: Full
Age range: Tonian Period (AT) — Tonian Period (AT)
Lithological Description: Coarse pelitic gneiss, garnetiferous, locally migmatitic, with gneissose semipelite and psammite. Quartzite occurs locally. Calcsilicate bands are common within psammite.
Definition of Lower Boundary: Overlies conformably the Reidh Psammite Fm (REP); where predominantly siliceous psammitic lithologies pass into predominantly pelitic lithologies.
Definition of Upper Boundary: Overlain by the Tarvie Psammite Formation (TAPS) - Loch Eil Group, where predominantly pelitic lithologies pass eastwards into predominantly psammitic lithologies.
Thickness: Highly variable, possibly up to 2-3 km.
Geographical Limits: Northern Highlands: Glen Affric to Dornoch Firth. Restricted to the Sgurr Beag Nappe.
Parent Unit: Glenfinnan Group (GLEN)
Previous Name(s): Ben Wyvis Pelite [Obsolete Name and Code: Use BWYP] (-4508)
Ben Wyvis Pelitic Schist [Obsolete Name and Code: Use BWYP] (-4509)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Tom na Chaillich. 
Reference(s):
Wilson, D. 1975. Structure and metamorphism of the Ben Wyvis District, Ross-shire. (University of Edinburgh: Unpublished PhD thesis.) 
Grant, C J. 1989. The kinematics and tectonic significance of ductile shear zones within the Northern Highland Moine. (University of Liverpool: unpublished PhD thesis.) 
Holdsworth, R E, Strachan, R A and Harris, A L, 1994. Precambrian rocks in northern Scotland east of the Moine Thrust: The Moine Supergroup in Gibbons, W and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, No.22. 
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). 
Roberts, A M, Strachan, R A, Harris, A L, Barr, D and Holdsworth, R E, 1987. The Sgurr Beag Nappe: A reassessment of the stratigraphy and structure of the Northern Highland Moine. Geological Society of America Bulletin, Vol.98, 497-506. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S093 S093 S093