The BGS Lexicon of Named Rock Units — Result Details

Ardair Semipelite Formation

Computer Code: ARDR Preferred Map Code: AR
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Interbedded schistose semipelite and micaceous psammite in roughly equal proportions
Definition of Lower Boundary: Transitional with underlying micaceous psammites of the Loch Laggan Psammite Formation.Marked by increase in semipelite and thin-banded micaceous psammite content.
Definition of Upper Boundary: Sharp to transitional with thinly bedded feldspathic and micaceous psammites of the Creag Meagaidh Psammite Formation
Thickness: 770m in type area.
Geographical Limits: South-western Monadhliath Highlands, Glen Roy - Glen Banchor, and Adverikie and Ben Alder Forest areas.
Parent Unit: Corrieyairack Subgroup (GRCO)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  South wall of Coire Ardair on Creag Meagaidh 
Reference Section  Roadcuts on north side of A86, north of Lower Laggan Reservoir. 
Reference Section  Summit area of Creag Pitridh - upper contact. 
British Geological Survey, 1995. Glen Roy, Scotland sheet 63W. Solid Geology 1:50000 (Keyworth, Nottingham, British Geological Survey). 
Key, R M, Clark, G C, May, F, Phillips, E R, Chacksfield, B C and Peacock, J D, 1997. Geology of the Glen Roy district. Memoir of the British Geological Survey, Sheet 63W [Scotland]. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S074 S063 S063 S073