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
Reference Section  Markie Burn, 700m upstream from Spey Dam. 
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. 
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]. 
British Geological Survey, 1995. Glen Roy, Scotland sheet 63W. Solid Geology 1:50000 (Keyworth, Nottingham, British Geological Survey). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S074 S063 S063