| Computer Code: |
BTYH |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Tonian Period (AT)
— Tonian Period (AT) |
| Lithological Description: |
Pink-grey psammite, gneissose, locally migmatitic, interlayered on cm-m scale with gneissose semipelite and pelite. Abundant quartzo-feldspathic segregations. At the structural base locally a c. 300 m thick sillimanite-bearing gneissose pelite unit. No sedimentary structures preserved. Abundant thin amphibolite lenses. |
| Definition of Lower Boundary: |
Unconformable upon Lewisian Gneiss inlier (L); unconformity highly sheared. In many places, base is cut and deformed by the Torrisdale thrust. |
| Definition of Upper Boundary: |
Unknown: cut by Swordly thrust. |
| Thickness: |
c. 1000-2000 m (post-deformational thickness). |
| Geographical Limits: |
Northern Sutherland: Ben Klibreck to Bettyhill. Occurs in Torrisdale thrust sheet only. |
| Parent Unit: |
Morar Group (MORR)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| none recorded or not applicable |
| Reference(s): |
| Holdsworth, R E, Strachan, R and Alsop, G I. 2001. Solid geology of the Tongue district; Memoir for 1:50 000 Geological Sheet 114 E (Scotland),British Geological Survey, Keyworth, Nottingham. |
| 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: |
|
S108
S109
S115
S114
|
