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): |
Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). |
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. |
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. |
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
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