The BGS Lexicon of Named Rock Units — Result Details

Garve Psammite Formation

Computer Code: GAPS Preferred Map Code: SYMB
Status Code: Full
Age range: Proterozoic Eon (AP) — Proterozoic Eon (AP)
Lithological Description: Buff to pale brown and pink, flaggy, siliceous and feldspathic psammite with micaceous partings, some heavy mineral bands and numerous streaky lenticles displaying quartzofeldspathic segregations.
Definition of Lower Boundary: Located at the Sgurr Beag Thrust Plane, which is commonly interdigitated with Lewisianoid tectonic slices. This formation is structurely the lowest Moine group unit in the Sgurr Beag Nappe.
Definition of Upper Boundary: Defined by the western edge of the Ben Wyvis Pelite Formation, with the appearance of predominantly pelitic rocks to the east. The boundary has probably been significantly tectonically modified.
Thickness: Not recorded.
Geographical Limits: Forms a thin, nearly continuous belt running south-west to north-east from Loch Luichart (NH383602) to Loch Coire (NH525762). South and west of Loch Luichart, it is repeated in a series of folds and thrusts; e.g.Sgurr Beag Thrust, extending to the west at Loch Bhad Ghaineamhaich (NH323590), where it terminates against the Strathconon Fault.
Parent Unit: Glenfinnan Group (GLEN)
Previous Name(s): Ben Wyvis Psammite (-274)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Beinn a' Ghuilbein, 3.2 km north-east of Garve. 
Reference(s):
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. 
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 (University of Edinburgh: Unpublished PhD thesis.)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 (University of Liverpool: unpublished PhD thesis.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S093 S093 S093