The BGS Lexicon of Named Rock Units — Result Details
Meall Dubh Quartzite Formation
| Computer Code: | MEDQ | Preferred Map Code: | MeDQ |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
| Lithological Description: | Quartzite, feldspathic, with heavy-mineral laminae, originally pebbly but now strongly recrystallised and flattened; cross-bedding visible in places. | ||
| Definition of Lower Boundary: | At base of transitional facies, c.2 - 3m thick, of finely-bedded fine-grained silty quartzite with black graphitic laminae which occurs just above contact with Meall Dubh Graphitic Schist Formation. | ||
| Definition of Upper Boundary: | Sharp boundary to finely-laminated semipelite of Strath Fionan Banded Semipelite Formation. | ||
| Thickness: | 10 - 180m in Sheet 55W; shows much tectonic thinning compared with Beinn a'Ghlo/Appin Quartzite. | ||
| Geographical Limits: | From Allt Druidhe [6424 5694] sporadically to Allt na Moine Biudhe [NN 7077 6112] and then continuously to south bank of Allt Kinardochy [7789 5727]. Not present east of the Loch Tay Fault, where its place is taken by the Beinn a'Ghlo Quartzite Formation. | ||
| Parent Unit: | Ballachulish Subgroup (DABH) | ||
| Previous Name(s): | Beinn A'Ghlo Quartzite Formation [Obsolete Name and Code: Use MEDQ]
(*185)
Meall Dubh Quartzite [Obsolete Name and Code: Use MEDQ] (-1060) Appin Quartzite [Obsolete Name and Code: Use MEDQ] (*921) |
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| Alternative Name(s): | Appin Quartzite [Obsolete: use MEDQ] Beinn A'Ghlo Quartzite Formation [Obsolete: use MEDQ] |
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| Stratotypes: | |||
| Type Section | South side of Meall Dubh, as far as road through Strath Fionan. | ||
| Reference(s): | |||
| Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). | |||
| 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. | |||
| Stephenson, D and Gould, D. 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. | |||
| 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. | |||
| Smith, R A and Harris, A L, 1976. The Ballachulish rocks of the Blair Atholl district. Scottish Journal of Geology, Vol.12, 153-157. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S055 | |||