| Computer Code: |
DIEP |
Preferred Map Code: |
SYMB |
| Status Code: |
Full |
| Age range: |
Tonian Period (AT)
— Tonian Period (AT) |
| Lithological Description: |
Massive, schistose, garnet-mica bearing pelite and semipelite, increasingly pelitic towards the top. Locally calc-silicate and psammite layers. The formation is partly hornfelsed in the thermal aureole of the Carn Chuinneag granite gneiss pluton: hornfelsed pelite locally preserves laminations, ripple marks, cross-bedding and possible mud cracks (Wilson and Shepherd, 1979). Andalusite and cordierite assemblages occur in the aureole. |
| Definition of Lower Boundary: |
Conformably upon the Crom Psammite Formation (CMPS). Defined as where predominantly psammitic lithologies pass into predominantly pelitic lithologies. |
| Definition of Upper Boundary: |
The upper boundary cannot be seen, as it is obscured by the Carn Chuinneag-Inchbae Granite Gneiss Intrusion. |
| Thickness: |
c. 200-400 m (minimum estimate). |
| Geographical Limits: |
NW Highlands, Central Ross-shire. Surrounds the northern part of the Carn Chuinneag intrusion. |
| Parent Unit: |
Morar Group (MORR)
|
| Previous Name(s): |
Upper Pelite [Obsolete Name and Code: Use DIEP]
(-4608)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Type area: Rocky spurs between Glencalvie Lodge and Carn na Speireig (south of Croick): [NH 460 887 - NH 435 880]. |
| Reference(s): |
| Wilson, D. 1975. Structure and metamorphism of the Ben Wyvis District, Ross-shire. (University of Edinburgh: Unpublished PhD thesis.) |
| 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. |
| 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. |
| Shepherd, J. 1970. The structure and metamorphism of the Carn Chuinneag area, Ross-shire. (University of Edinburgh.: unpublished PhD thesis.) |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S093
S093
S093
|
