The BGS Lexicon of Named Rock Units — Result Details

Appin Group

Computer Code: APP Preferred Map Code: App
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Alternating units of psammite to quartzite and semipelite to pelite in Lochaber Subgroup. In the Ballachulish and Blair Atholl Subgroups, pelitic and calcareous lithologies dominate, although one clean-washed, locally pebbly quartzite in the Ballachulish Subgroup is persistent from Donegal to Banffshire. Many of the pelitic and calcareous rocks are graphitic.
Definition of Lower Boundary: Generally rapid transition from monotonous psammite, generally flaggy, with thin quartzite and semipelite units of underlying Grampian Group, to better sorted psammite or quartzite and semipelite or pelite.
Definition of Upper Boundary: Transition from graphitic semipelite and limestone to psammite and quartzite with rare semipelite, or locally to diamictite.
Thickness: Typically 4km where untectonised, but thinned sequence (1km or less) occurs over structural highs.
Geographical Limits: Connemara; North Mayo; Donegal west of Main Donegal Granite; Lismore to Glen Spean; Kinlochlaggan; Kinloch Rannoch via Glen Shee to Braemar; Glen Livet; Dufftown to Banffshire coast (Findlater Castle to Portsoy). The Appin Group is also roughly equivalent to the Scatsta Division of Shetland.
Parent Unit: Dalradian Supergroup (DALN)
Previous Name(s): Lower Dalradian Group [Obsolete Name And Code: See APP] (DA)
Alternative Name(s): Lower Dalradian
Stratotypes:
Type Area  Appin, Lismore, Loch Leven. 
Reference(s):
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 and Maufe, H B, 1960. The geology of Ben Nevis and Glen Coe (Second Edition). Memoir of the Geological Survey of the United Kingdom. (Scotland, Sheet 53). 
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. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S019 S027 S045 S045 S053 S054 S054 S055 S055 S056 S063 S063 S064 S065 S065 S075 S075 S085 S085 S086 S095 S096 S044 S036 S062 S086 S096 S053 S046