The BGS Lexicon of Named Rock Units — Result Details

Easdale Subgroup

Computer Code: DBED Preferred Map Code: Eas
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Semipelite and pelite, the pelitic lithologies graphitic in lower part and calcareous in upper part, with pebbly quartzite developed in part of succession over wide areas; volcaniclastic formation locally present at top of subgroup.
Definition of Lower Boundary: Abrupt transition from quartzite to graphitic pelite (Jura, Easdale) or mixed semipelite, pelite and psammite (Perthshire).
Definition of Upper Boundary: Top of Farragon Volcanic Formation in Perthshire; base of Crinan Grit or Upper Erins Quartzite in Argyll.
Thickness: Up to 3km
Geographical Limits: Connemara; North Mayo; Donegal; Jura, Knapdale and Mid-Argyll; from Loch Fyne, via Tyndrum, Loch Tay, Loch Tummel, Glen Shee, Deeside, Donside and Ladder Hills to the Moray firth coast from Portsoy to Boyne Bay.
Parent Unit: Argyll Group (ARGY)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  East Jura, Scarba, Luing, Easdale and mid-Argyll. (Baldwin, C T and Johnson, H D, 1977). 
Reference(s):
Baldwin, C T and Johnson, H D, 1977. The Dalradian rocks of Lunga, Luing and Shuna. Scottish Journal of Geology, Vol.13, 143-154. 
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. 
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. 
Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S019 S027 S028 S028 S036 S037 S037 S045 S045 S046 S047 S053 S054 S055 S055 S056 S065 S065 S075 S075 S085 S086 S096 S029 S044 S086 S046 S047 S047