The BGS Lexicon of Named Rock Units — Result Details

Lower Dalradian Group [Obsolete Name And Code: See APP]

Computer Code: DA Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Relatively thin formations of limestone, commonly carbonaceous pelite, quartzite and characteristic striped and laminated pelite-psammite basal quartzites and semi-pelites.
Definition of Lower Boundary: Drawn at base of interbanded quartzites and semi-pelites possibly belonging to the Lochaber Sub-Group, where it rests conformably on sandstones of the Grampian Group.
Definition of Upper Boundary: Drawn at conformable upward passage from limestone intepreted to be of the Blair Atholl Sub-Group to tillite interpreted to be of the Islay Sub-Group.
Thickness: Not known.
Geographical Limits: Shetland, Grampian, Highland, Tayside, Central, Strathclyde, Inner Hebrides, Scotland. Donegal, Mayo, Connemara, Ireland.
Parent Unit: Dalradian Rocks (Undifferentiated) [Obsolete Name And Code: See DALN] (D)
Previous Name(s): Lower Dalradian Group (Now Appin Group) (-182)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Appin area, Strathclyde, Scotland. 
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. 
Rast, N and Litherland, M, 1970. The correlation of the Ballachulish and Perthshire (Iltay) Dalradian successions. Geological Magazine, Vol.107, p.259-272. 
Hickman, A H, 1983. Geochemistry and chemostratigraphical correlation of slates, marbles and quartzites of the Appin Group, Argyll, Scotland. Transactions of the Royal Society of Edinburgh, Vol.73, p.251-278. 
Rast, N, 1963. Structure and metamorphism of the Dalradian rocks of Scotland. "In" Johnson, M R W and Stewart, F H, (Editors). The British Caledonides, Edinburgh, p.123-142. 
Anderson, J G C. 1948. Stratigraphic nomenclature of Scottish metamorphic rocks. Geological Magazine, Vol.85, 89-96. 
Knill, J L, 1963. A sedimentary history of the Dalradian Series. "In" Johnson, M R W and Stewart, F H, (Editors). The British Caledonides, p.99-121. 
Wilson, H E. 1972. The regional geology of Northern Ireland. (Belfast: HMSO for Geological Survey of Northern Ireland.) 113pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable