The BGS Lexicon of Named Rock Units — Result Details
Loch Laggan Psammite Formation
| Computer Code: | LLGN | Preferred Map Code: | LL |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
| Lithological Description: | Predominantly micaceous and feldspathic psammite with thin semipelite beds; turbiditic features. Abundant calc-silicate rock lenses and bands. Transitional upper and lower contacts. | ||
| Definition of Lower Boundary: | Transitional with underlying Coire nan Laogh Semipelite. Base marked by lowest thick (10 m +) grey psammite. | ||
| Definition of Upper Boundary: | Transitional into overlying Ardair Semipelite - progressive increase in mica content. | ||
| Thickness: | variable 1.5 - 3.5 km | ||
| Geographical Limits: | Central and southern Monadhliath Mountains, from Glen Roy to Strath Nairn and eastwards to Aviemore (Speyside). | ||
| Parent Unit: | Corrieyairack Subgroup (GRCO) | ||
| Previous Name(s): | Glen Doe Psammite Formation
(GDOE)
Glen Doe Psammite Formation (GDOE) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Shoreside exposures north side of Loch Laggan around Rubha na Magach. | ||
| Type Area | Loch Lagganside to Glenshirra. Base on south side of upper Spey valley in Coire Bhein. Top on road cuts and sections above Moyonlaggan side. | ||
| Reference Section | South-western flank of Beinn Sgurrach down from top to River Fechlin. | ||
| Reference(s): | |||
| British Geological Survey. 1995. Glen Roy, Scotland sheet 63W. 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.) | |||
| 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]. | |||
| 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: | |||
| S074 S074 S064 S064 S063 S063 S073 S073 | |||