The BGS Lexicon of Named Rock Units — Result Details
Tarvie Psammite Formation
| Computer Code: | TAPS | Preferred Map Code: | SYMB |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Tonian Period (AT) — Tonian Period (AT) | ||
| Lithological Description: | Predominantly psammite, thin-bedded, siliceous to micaceous. Local, thin semipelite beds are muscovite-rich and locally migmatitic. Large quartzite lenses occur, in particular near the base. Tends to become more micaceous to the NE. Psammite is generally fine-grained. Locally well-developed cross-bedding, in places showing herring-bone cross-bedding, and symmetric ripple marks. | ||
| Definition of Lower Boundary: | Overlies the Ben Wyvis Pelite Formation (BWYP) along the western boundary, where predominant pelites pass into predominantly psammitic lithologies. Similarly overlies the Achnaconeran Striped Formation (ACHN) and the Achnacarry Formation (ACNS) in the east. | ||
| Definition of Upper Boundary: | Not known. Commonly unconformably overlain by Old red Sandstone. | ||
| Thickness: | At least 2.5 km thick, up to about 5 km. | ||
| Geographical Limits: | Northern Highlands, from Loch Linhe to the Dornoch Firth and in numerous outliers. Restricted to the Sgurr Beag Nappe. | ||
| Parent Unit: | Loch Eil Group (LEIL) | ||
| Previous Name(s): | Tarvie Psammite [Obsolete Name and Code: Use TAPS]
(-2474)
Tarvie Psammitic Group [Obsolete Name and Code: Use TAPS] (-3710) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Cnoc na Gearraisich, 4.5 km NNW of Strathpeffer. | ||
| Reference(s): | |||
| Wilson, D. 1975. Structure and metamorphism of the Ben Wyvis District, Ross-shire. (University of Edinburgh: Unpublished PhD thesis.) | |||
| Johnstone, G S, Smith, D I, and Harris, A L. 1969. The Moinian Assemblage of Scotland. In: Kay, M. (editor). North Atlantic Geology and Continental Drift: A Symposium. Memoirs of the American Association of Petroleum Geologists, Vol. 12, 159-180. | |||
| Holdsworth, R E, Strachan, R A and Harris, A L, 1994. Precambrian rocks in northern Scotland east of the Moine Thrust: The Moine Supergroup in Gibbons, W and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, No.22. | |||
| Strachan, R A, May, F and Barr, D, 1988. The Glenfinnan and Loch Eil Divisions of the Moine Assemblage. 32-45 IIV Winchester, J A (editor). Later Proterozoic stratigraphy of the Northern Atlantic regions (Glasgow and London: Blackie). | |||
| Strachan, R A. 1986. Shallow marine sedimentation in the Proterozoic Moine succession, northern Scotland: Precambrian Research, v. 32, no. 1, p. 17-33. | |||
| 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: | |||
| S083 S093 S093 S093 | |||