The BGS Lexicon of Named Rock Units — Result Details

Strathtummel Subgroup

Computer Code: STEL Preferred Map Code: StrT
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Interbedded psammite and quartzite units, mostly thickly-bedded, with internal features suggesting deposition in a shallow marine shelf environment.
Definition of Lower Boundary: Gradational boundary with Bruar Psammite Formation at base of Tummel Quartzite Formation.
Definition of Upper Boundary: Sharp, conformable boundary at top of Kynachan Psammite Formation with Dunalastair Quartzite Formation (Lochaber Subgroup, Appin Group).
Thickness: 1000 - 3800m on limbs of Meall Reamhar Synform; lower limit probably involves tectonic thinning, but upper limit may involve tectonic thickening.
Geographical Limits: From closure of Errochty Synform [NN 710 671] north-east to A9 road near Dalnamine [NN 750 700, then due east to Loch Tay Fault at [NN 880 700], then along Loch Tay Fault to Loch Tummel [NN 802 598], and thence back to the closure of the Errochty Synform via the northern boundary of the Dunalastair Formation. Possible extension of this area to north-west not defined.
Parent Unit: Grampian Group (GRAM)
Previous Name(s): Strathtummel Succession (-3053)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Type section of Tummel Psammite Formation. South side of River Tummel and Dunalastair Reservoir from weir below Dunalastair Dam. 
Type Section  Type section of Kynachan Quartzite and Kynachan Psammite formations. South side and main ridge of Creag Kynachan. 
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. 
Thomas, P R, 1980. The stratigraphy and structure of the Moine rocks north of the Schiehallion Complex, Scotland. Journal of the Geological Society, London, Vol.137, 469-482. 
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 S055