The BGS Lexicon of Named Rock Units — Result Details
Cnoc An Fhithich Banded Semipelite Formation
Computer Code: | CAFS | Preferred Map Code: | CnFS |
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Status Code: | Full | ||
Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
Lithological Description: | Banded alternation of rusty-weathering semipelite with 5 - 10cm beds of psammite in equal proportions; however 25% of upper part of formation consists of white, quartz-rich psammite alternating with dark, biotitic, graded pelite. | ||
Definition of Lower Boundary: | Transitional, with interbanding of calcareous semipelite with thin grey limestone beds marks junction with upper limestone of Blair Atholl Dark Limestone and Dark Schist Formation. | ||
Definition of Upper Boundary: | Sharp boundary with buff limestone of Drumchastle Pale Limestone Formation at type locality; elsewhere taken at base of calc-muscovite-biotite pelite lithology transitional to Drumchastle Pale Limestone Formation. | ||
Thickness: | 0 - 150m in Sheet 55W; probably tectonically attenuated. | ||
Geographical Limits: | From east side of Errochty Synform at Errochty Water [NN 7245 6480] discontinuously to near Braes of Foss [NN 7465 5590]. East of the Loch Tay Fault and north of the Killiecrankie Slide, it occurs from Allt Bhaic [NN 840 640] and on the eastern slopes of Glen Tilt [NN 886 680 - 898 713 and NN 912 714 - 942 745]. | ||
Parent Unit: | Blair Atholl Subgroup (DABA) | ||
Previous Name(s): | Banded Series within Pale Group of Blair Atholl Series [Obsolete Name and Code: Use CAFS]
(-3896)
Banded Group within Blair Atholl Subgroup [Obsolete Name and Code: Use CAFS] (-103) Banded Schist within Blair Atholl Subgroup [Obsolete Name and Code: Use CAFS] (-104) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | 300m north of Allt Leathan, on eastern slopes of Cnoc an Fhithich. | ||
Reference(s): | |||
Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). | |||
Bailey, E B, 1925. Perthshire tectonics: Loch Tummel, Blair Atholl and Glen Shee. Transactions of the Royal Society of Edinburgh, Vol.53, 671-698. | |||
Barrow, G, Grant Wilson, J S and Cunningham Craig, E H, 1905. The geology of the country around Blair Atholl, Pitlochry and Aberfeldy. Memoir of the British Geological Survey, Scotland (Sheet 55). | |||
Smith, R A and Harris, A L, 1976. The Ballachulish rocks of the Blair Atholl district. Scottish Journal of Geology, Vol.12, 153-157. | |||
Stephenson, D and Gould, D. 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. | |||
Bailey, E B and McCallien, W J, 1937. Perthshire tectonics: Schiehallion to Glen Lyon. Transactions of the Royal Society of Edinburgh, Vol.59, 79-117. | |||
Harris, A L, Haselock, P J, Kennedy, M J and Mendum, J R, 1994. The Dalradian Supergroup in Scotland, Shetland and Ireland. 33-53 in Gibbons, W E and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, London, No.22. | |||
Treagus, J E and King, G, 1978. A complete Lower Dalradian succession in the Schiehallion district, central Perthshire. Scottish Journal of Geology, Vol.14, 157-166. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
S055 S055 S064 |