The BGS Lexicon of Named Rock Units — Result Details

Creag Meagaidh Psammite Formation

Computer Code: CGMG Preferred Map Code: CM
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Flaggy to blocky feldspathic and micaceous psammites. Minor semipelite interbeds and calc-silicate rock lenses. Rare feldspathic quartzite.
Definition of Lower Boundary: Sharply transitional - marked by incoming of flaggy psammites above semipelite-psammite interbeds of the Ardair Semipelite Formation.
Definition of Upper Boundary: Sharply transitional into overlying fissile, schistose semipelites of the Clachaig Formation.
Thickness: 500m - 765m maximum.
Geographical Limits: Southern Monadhliath Mountains: Glen Roy - Laggan - Glen Banchor districts.
Parent Unit: Corrieyairack Subgroup (GRCO)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  East side of Beinn a' Chaorainn in Coire na H-uamha, North Glen Spean. 
Reference Section  Roadcuts on A86 and small quarry north of Lower Loch Laggan. 
Reference Section  Markie Burn, 700m upstream from Spey Dam. 
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