| Computer Code: |
TAT |
Preferred Map Code: |
TAT |
| Status Code: |
Full |
| Age range: |
Stenian Period (AI)
— Stenian Period (AI) |
| Lithological Description: |
Basal cobble-boulder conglomerate, followed by pebbly, coarse sandstone and medium- fine cross-bedded sandstone, with local beds of red mudstone, red muddy sandstone with dessication cracks, ripple laminations and rare calcareous beds. |
| Definition of Lower Boundary: |
Unconformable on Lewisian Gneiss Complex (L). The unconformity is sharp without weathering. The landscape on which the Clachtoll Formation was deposited was hilly, with palaeo-valley several 100 m deep. |
| Definition of Upper Boundary: |
Conformably overlain by Bay of Stoer Formation (TAS). The contact is defined as an erosion surface overlain by pebbly red sandstones of the Bay of Stoer Formation. |
| Thickness: |
0-190 m (highly variable). |
| Geographical Limits: |
Occurs in 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 - Coast section 500 m south and 300 m west of Clachtoll village. [NC 041 265 - NC 037 272]. |
| 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.) |
| Parnell, J., Mark, D., Fallick, T.E., Boyce, A. and Thackrey, S., 2011. The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland. Journal of the Geological Society of London, 168: 349 - 358. |
| 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: |
|
S091
S092
S107
|
