The BGS Lexicon of Named Rock Units — Result Details

Meall Dubh Limestone Formation

Computer Code: MEDL Preferred Map Code: MeDL
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Yellow-weathering, grey dolomitic metalimestone, striped calcareous schist, tremolite-actinolite schist with biotite or phlogopite porphyroblasts and rosettes of tremolite.
Definition of Lower Boundary: Boundary with Meall Dubh Striped Pelite Formation probably transitional over a few metres.
Definition of Upper Boundary: Gradational boundary with the Meall Dubh Graphitic Schist Formation with admixture of graphitic and calc-schists is poorly exposed.
Thickness: 3 - 15m in Sheet 55W; much tectonic thinning compared with Ballachulish Limestone.
Geographical Limits: Main development in Strath Fionan [NN 7257 7556]. Also occurs sporadically as far west as Allt na Moine Buidhe [NN 708 612] and as far east as Allt Kynachan [NN 7790 5725]. Not present east of the Loch Tay Fault in Sheets 55E and 64E, where it is tectonically excised, but possibly equivalent to Baddoch Burn Dolomite in Sheet 65W; however some of the rocks of the 'Banvie Burn Series' may be equivalent.
Parent Unit: Ballachulish Subgroup (DABH)
Previous Name(s): Meall Dubh Limestone (-1059)
Baddoch Burn Dolomite (*310)
Ballachulish Limestone (*311)
Alternative Name(s): Baddoch Burn Dolomite
Ballachulish Limestone
Stratotypes:
Type Area  Crags on north side of road through Strath Fionan, c.1km west-north-west of Braes of Foss. 
Reference(s):
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. 
Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). 
Stephenson, D and Gould, D , 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S055