The BGS Lexicon of Named Rock Units — Result Details

Glascarnoch Psammite Formation

Computer Code: GLPS Preferred Map Code: SYMB
Status Code: Full
Age range: Proterozoic Eon (AP) — Proterozoic Eon (AP)
Lithological Description: Massive, white to grey and buff, feldspathic and siliceous psammite with rare semipelitic and pelitic bands.
Definition of Lower Boundary: Gradational boundary with the Glen Achall Psammite And Semipelite Member
Definition of Upper Boundary: Lower (western) margin of Vaich Pelite Formation where predominantly psammitic lithologies pass into predominantly pelitic lithologies.
Thickness: Not recorded.
Geographical Limits: Forms a continuous north-south trending belt approximately west of gridline 2300, crossing the western end of Loch Glascarnoch northwards to the western end of Gleann Beag, and continuing north into Strath Mulzie. Extent beyond Strath Mulzie is unclear. The western boundary is not well defined to the north, but appears to extend to Inverlael Forest in upper Loch Broom, trending southwards through Braemore Forest to Loch Fannich. To the south and west of Loch Fannich through Starth Bran, the western boundary runs approximately along Glen Carron, then trending southwards to the western end of Loch Monar, but this is unclear. The extent of the outcrop is also unclear south and west of Loch Monar, where it may terminate on the north-west side of the Strathconon Fault.
Parent Unit: Morar Group (MORR)
Previous Name(s): Lower Psammite (-4677)
Lower Quartzite (-1562)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Meall an Daimh Bhig in upper Strath Mulzie. 
Reference(s):
Bonsor, H, Strachan, R, Prave, A and Krabbendam, M. 2012. Sedimentology of the early Neoproterozoic Morar Group in northern Scotland: implications for basin models and tectonic setting. Journal of the Geological Society of London 169, 53-65. 
Shepherd, J. 1970. The structure and metamorphism of the Carn Chuinneag area, Ross-shire. (University of Edinburgh.: unpublished PhD thesis.) 
Wilson, D. 1975. Structure and metamorphism of the Ben Wyvis District, Ross-shire. (University of Edinburgh: Unpublished PhD thesis.) 
Bonsor, H C, Strachan, R A, Prave, A and Krabbendam, M. 2010. Fluvial braidplain to shallow marine transition in the early Neoproterozoic Morar Group, Fannich Mountains, northern Scotland. Precambrian Research 183, 791-804. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S083 S093 S093