The BGS Lexicon of Named Rock Units — Result Details
Ballachulish Subgroup
| Computer Code: | DABH | Preferred Map Code: | Bchu |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
| Lithological Description: | Basal limestone, succeeded upward by graphitic pelite; this in turn overlain by persistent quartzite, which is overlain by striped semipelite with thin limestone units. | ||
| Definition of Lower Boundary: | At top of the Lochaber Subgroup: in most areas there is a prominent limestone at the base of the Ballachulish Subgroup: also pelites become markedly graphitic at boundary. | ||
| Definition of Upper Boundary: | At base of Blair Atholl Subgroup: generally at the transition from banded semipelite and limestone to more graphitic pelite with limestone beds. | ||
| Thickness: | c.500-1100m (but locally tectonically thinned to 100m) | ||
| Geographical Limits: | Islay; Appin to Lochaber; also a thin strip from near Loch Errochty to the Moray Firth coast at Sandend Bay (between Cullen and Portsoy). Also occurs in Ireland extensively in Co. Donegal. | ||
| Parent Unit: | Appin Group (APP) | ||
| Previous Name(s): | Ballachulish Group [Obsolete Name and Code: Use DABH]
(-1473)
Blair Atholl Series (-835) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Section | (Local). Traverse running south across Strath Fionan, commencing c.1km westsouthwest of Lochan Beoil. Line B-B' on Figure 4 of Treagus, J E. 2001. | ||
| Type Area | Ballachulish, Argyll. | ||
| Type Area | Strath of Appin and Island of Shuna, east shore of Loch Linnhe. Litherland, 1980. | ||
| Reference(s): | |||
| Litherland, M, 1980. The stratigraphy of the Dalradian rocks around Loch Creran, Argyll. Scottish Journal of Geology, Vol.16, 105-123. | |||
| Stephenson, D and Gould, D. 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey.) | |||
| 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). | |||
| 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. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). | |||
| Smith, R A and Harris, A L, 1976. The Ballachulish rocks of the Blair Atholl district. Scottish Journal of Geology, Vol.12, 153-157. | |||
| 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. | |||
| Bailey, E B. 1934. West Highland tectonics, Loch Leven to Glen Roy. Quarterly Journal of the Geological Society of London, 90, 462. | |||
| Harris, A L and Pitcher, W S, 1975. The Dalradian Supergroup. "In" Harris, A L, Shackleton, R M, Watson, J, Downie, C, Harland, W B and Moorbath, S. A correlation of the Precambrian rocks in the British Isles. Geological Society Special Report, No.6. p.52-75. Scottish Academic Press, Edinburgh. | |||
| Bailey, E B. 1910. Recumbent folds in the schists of the Scottish Highlands. Quarterly Journal of the Geological Society of London, 66, 592. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S019 S027 S044 S045 S053 S055 S055 S064 S065 S065 S075 S075 S085 S086 S096 S045 S062 S063 S063 S096 S054 S054 S046 S053 | |||