The BGS Lexicon of Named Rock Units — Result Details

Upper Morar Psammite Formation

Computer Code: MAUP Preferred Map Code: notEntered
Status Code: Full
Age range: Tonian Period (AT) — Tonian Period (AT)
Lithological Description: Dominated by siliceous, feldspathic to micaceous psammite, from course to fine grained, locally quartzitic. Commonly pebbly and gritty bands; also semipelitic layers and calc-silicate bands. Abundant cross-bedding and soft-sediment deformation structures.
Definition of Lower Boundary: Conformably upon the Morar Schists Formation (MAMS).
Definition of Upper Boundary: Unknown: not exposed.
Thickness: c. 2500 m (minimum; estimate).
Geographical Limits: NW Highlands: Ardnamurchan, Morar, Knoydart, Kintail.
Parent Unit: Morar Group (MORR)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Type section: northern shore of Arnamurchan peninsula [NM 611 691 - NM 548 716]. 
Reference Section  Reference section: northern shore of Rhue peninsula: [NM 654 852 - NM 611 848]. 
Reference(s):
Krabbendam, M. 2021. A stratigraphic framework for the early Neoproterozoic successions of the Northern Highlands of Scotland. UK Stratigraphic Framework Series. British Geological Survey Open Report, OR/21/072. 86pp. 
Bonsor H C, and Prave A R. 2008. The Upper Morar Psammite of the Moine Supergroup, Ardnamurchan Peninsula, Scotland: depositional setting, tectonic implications. Scottish Journal of Geology 44, 1-12. 
Ramsay, J.G. and Spring, J., 1962. Moine stratigraphy in the Western Highlands of Scotland. Proceedings of the Geological Association, 73: 295-326. 
Glendinning, N R W. 1988. Sedimentary structures and sequences within a late Proterozoic tidal shelf deposit: the Upper Morar Psammite Formation of northwestern Scotland. In Winchester, J (ed). Later Proterozoic stratigraphy of the Northern Atlantic regions Blackie, 14-31. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S061 S061 S062