| Computer Code: |
TCD |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Tonian Period (AT)
— Tonian Period (AT) |
| Lithological Description: |
Breccias and conglomerates, locally interbedded with red sandstone. These typically pass into variable, generally thin-bedded grey shales and tabular sandstone. |
| Definition of Lower Boundary: |
Unconformable upon Lewisian Gneiss (L). |
| Definition of Upper Boundary: |
Overlain by Applecross Formation (incoming of thick-bedded, cross-bedded sandstone), normally with sharp boundary, possibly with low-angle unconformity. |
| Thickness: |
Highly variable, maximum c. 200 m. |
| Geographical Limits: |
Northwest Highlands, from Assynt to Rum. |
| Parent Unit: |
Torridon Group (TC)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Diabaig, coastal section [NG 797 601 - NG 793 603]. |
| 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. 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. |
| Callow, R H, Battison, L, and Brasier, M D. 2011. Diverse microbially induced sedimentary structures from 1 Ga lakes of the Diabaig Formation, Torridon Group, northwest Scotland. Sedimentary Geology, 239 (3-4), 117-128. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S107
S071
S108
S081
S082
S092
S101
S101
S081
S102
S060
S091
|
