| Computer Code: |
TB |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Tonian Period (AT)
— Tonian Period (AT) |
| Lithological Description: |
Slightly metamorphosed cross-bedded grey sandstones and shaly mudstones. The sandstones are poorly sorted and resemble feldspathic greywackes. |
| Definition of Lower Boundary: |
Drawn at base of breccia and sandstone of the Rubha Guail Formation where it rests unconformably on Lewisian Gneisses. |
| Definition of Upper Boundary: |
Overlain by Applecross Formation, Torridon group (incoming of trough cross-bedded sandstone), with low-angle unconformity (Kinnaird et al., 2007). |
| Thickness: |
3500m approx. |
| Geographical Limits: |
Northwest Scotland: Isle of Skye; Sleat to Kishorn. |
| Parent Unit: |
Wester Ross Supergroup (WROS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Sleat, Isle of Skye, Scotland. |
| Reference(s): |
| Stewart, A D. 2002. The later Proterozoic Torridonian rocks of Scotland: their sedimentology, geochemistry and origin. Geological Society Memoir. Vol. 24. (The Geological Society.) |
| Krabbendam, M, Bonsor, H, Horstwood, M S, and Rivers, T. 2017. Tracking the evolution of the Grenvillian foreland basin: Constraints from sedimentology and detrital zircon and rutile in the Sleat and Torridon groups, Scotland. Precambrian Research, Vol. 295, 67-89. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S071
S071
S081
S092
S061
|
