| Computer Code: |
DABA |
Preferred Map Code: |
BlAt |
| Status Code: |
Full |
| Age range: |
Neoproterozoic Era (AZ)
— Neoproterozoic Era (AZ) |
| Lithological Description: |
Semipelite and pelite, much of it graphitic; interbedded with limestone units, the lower limestones typically graphitic, the uppermost typically dolomitic |
| Definition of Lower Boundary: |
At top of Ballachulish Subgroup; generally at the transition from banded semipelite and limestone to more graphitic pelite with limestone beds. |
| Definition of Upper Boundary: |
At base of Islay Subgroup; generally transitional over a few metres where pale dolomitic limestone passes into psammite or quartzite with beds or larger units of diamictite. |
| Thickness: |
c.300 to 600m (but locally tectonically thinned to 50m) |
| Geographical Limits: |
Islay; Lismore; Appin; also a strip from near Blair Atholl to the Moray Firth coast at Sandend Bay (between Cullen and Portsoy). Also occurs in Ireland around Glencolumbkille and Falcarragh (Donegal) and in Connemara (Co. Galway). |
| Parent Unit: |
Appin Group (APP)
|
| Previous Name(s): |
Blair Atholl Series
(-835)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
In vicinity of Blair Atholl; bounded to west by Loch Tay Fault and to east by Killiecrankie Slide. |
| Type Section |
(Local). Traverse running south from Allt Leathan, 800m south of Lochan an Daim. On Line C-C' (see Figure 4 of Treagus, J E. 2001). |
| Partial Type Section |
East end of Sandend Bay: lower part of succession partly obscured by beach deposits and ?Middle Devonian breccia: cut off to east by north west-south east fault. |
| 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. |
| Treagus, J E. 2001. Solid geology of the Schiehallion district. Memoir of the British Geological Survey, Sheet 55W (Scotland). |
| Bailey, E B. 1925. Perthshire tectonics: Loch Tummel, Blair Atholl and Glen Shee. Transactions of the Royal Society of Edinburgh, Vol. 53, 671-698. |
| Bailey, E B, and McCallien, W J. 1937. Perthshire tectonics: Schiehallion to Glen Lyon. Transactions of the Royal Society of Edinburgh, Vol. 59, 79-117. |
| 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. |
| 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. |
| Barrow, G, Grant Wilson, J S, and Cunningham Craig, E H. 1905. The geology of the country around Blair Atholl, Pitlochry and Aberfeldy. Memoir of the British Geological Survey, Scotland (Sheet 55). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S019
S027
S044
S044
S045
S053
S055
S055
S056
S064
S065
S065
S075
S075
S085
S086
S096
S036
S096
S053
|
