The BGS Lexicon of Named Rock Units — Result Details
Tarff Banded Formation
| Computer Code: | TARF | Preferred Map Code: | T |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
| Lithological Description: | Interbedded semipelite and micaceous psammite, contains distinctive garnets with snowball and spiral inclusion patterns in semipelites near shear zones. Quartzite and pelite interbeds, notably in basal part. | ||
| Definition of Lower Boundary: | Conformable transition from underlying Glen Doe Psammite to semipelite/micaceous psammite-dominated sequence. Locally marked by appearance of impersistent quartzite beds and striped psammites. | ||
| Definition of Upper Boundary: | Not seen - faulted and sheared with Glen Buck Pebbly Psammite Formation. | ||
| Thickness: | Minimum 2.7km up to c. 3km. | ||
| Geographical Limits: | South-western Monadhliath Mountains in Central Highland of Scotland (SE of Great Glen). | ||
| Parent Unit: | Corrieyairack Subgroup (GRCO) | ||
| Previous Name(s): | none recorded or not applicable | ||
| Alternative Name(s): | Monadhliath Semipelite Formation Ardair Semipelite Formation |
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| Stratotypes: | |||
| Type Area | North of Coire Odhar Beag, to Glen Tarff. | ||
| Partial Type Section | Basal contact at Carn a' Chuillin. | ||
| Reference(s): | |||
| Key, R M, Clark, G C, May, F, Phillips, E R, Chacksfield, B C and Peacock, J D, 1997. Geology of the Glen Roy district. Memoir of the British Geological Survey, Sheet 63W [Scotland]. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S063 S073 | |||