The BGS Lexicon of Named Rock Units — Result Details
Monadhliath Semipelite Formation
| Computer Code: | MNSP | Preferred Map Code: | M |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
| Lithological Description: | Interbedded thin micaceous psammites and semipelites with subordinate feldspathic and siliceous psammite and quartzite. Quartzite is more common in the basal part of the formation. | ||
| Definition of Lower Boundary: | Overlies Glen Doe Psammite and Loch Laggan Psammite Formations. Marked by gradual increase in semipelite beds in top of psammite formations. | ||
| Definition of Upper Boundary: | With increase in micaceous psammite and feldspathic psammite passes up transitionally into Carn Leac Psammite Formation (Foyers District - Haselock et al, 1982. Sheet 73E) and the Auchivarie Psammite Formation (Glen Roy district - Key et al, 1997. Sheet 63W). See May and Highton (1997). | ||
| Thickness: | Up to 2km in type area, west of the Corrieyairack Pass. | ||
| Geographical Limits: | Central and south-western Monadhliath Highlands, Loch Killin to Fort Augustus district. | ||
| Parent Unit: | Corrieyairack Subgroup (GRCO) | ||
| Previous Name(s): | Tarff Banded Formation
(TARF)
Ardair Semipelite Formation (ARDR) Tarff Banded Formation (TARF) Ardair Semipelite Formation (ARDR) |
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| Alternative Name(s): | Tarff Banded Formation Ardair Semipelite Formation |
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| Stratotypes: | |||
| Reference Section | River Tarff - basal contact tectonic, upper contact not exposed. | ||
| Type Area | Ovoid area ca. 10km x 2.5km, south and east of Loch Killin [in core of large F2 fold], upper and lower contacts intact. | ||
| 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]. | |||
| British Geological Survey. 1995. Glen Roy, Scotland sheet 63W. Solid Geology 1:50 000 (Keyworth, Nottingham: British Geological Survey.) | |||
| British Geological Survey. 1993. Invermoriston, Scotland. Sheet 73W. Solid Geology, 1:50 000 (Keyworth, Nottingham: British Geological Survey.) | |||
| British Geological Survey. 1996. Foyers Scotland Sheet 73E. Solid geology 1:50 000. (Keyworth, Nottingham: British Geological Survey.) | |||
| May, F and Highton, A J, 1997. Geology of the Invermoriston district. Memoir of the British Geological Survey, sheet 73W [Scotland]. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S073 S073 | |||