| Computer Code: |
TAS |
Preferred Map Code: |
TAS |
| Status Code: |
Full |
| Age range: |
Stenian Period (AI)
— Stenian Period (AI) |
| Lithological Description: |
Main formation: red, coarse pebbly sandstone, thick bedded, abundant cross bedding and with soft-sediment deformation structures. Thinner beds of mudstone and thin-bedded mudstone-sandstone alternations. Sandstone with mafic fragments and accretionary lapilli (Stac Fada Member) and mudstone (Poll' a Mhuilt Member) at top of formation. |
| Definition of Lower Boundary: |
Conformably overlies the Clachtoll Formation (TAT). The contact is defined as an erosion surface where pebbly red sandstones of the Bay of Stoer Formation overlie muddy red sandstone of the Clachtoll Formation. |
| Definition of Upper Boundary: |
Conformably overlain by the Meall Dearg Formation (TAD), marked by the incoming of red sandstone overlying the mudstones of the Pollt a Mhuilt Member. |
| Thickness: |
At Stoer: 240 m maximum, of which top 100 m is Pollt a' Mhuilt Member. Near Loch Maree, c. 1000 m. |
| Geographical Limits: |
Occurs on several headlands (Stoer peninsula, Rubha Coigach) and near Gairloch, in the NW Highlands, east of the Coigach Fault, and west of the Moine Thrust. |
| Parent Unit: |
Stoer Group (TA)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Type Section - Coastal section along Bay of Stoer; [NC 037 272 - NC 030 285]. |
| 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.) |
| Rainbird, R.H., Hamilton, M.A. and Young, G.M., 2001. Detrital zircon geochronology and provenance of the Torridonian, NW Scotland. Journal of the Geological Society of London, 158: 15-27. |
| 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: |
|
S107
S091
|
