The BGS Lexicon of Named Rock Units — Result Details
Loch Laggan Psammite Formation
Computer Code: | LLGN | Preferred Map Code: | LL |
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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: | |||
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 Section | Shoreside exposures north side of Loch Laggan around Rubha na Magach. | ||
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 |