The BGS Lexicon of Named Rock Units — Result Details

Central Grampian (Albion) Glacigenic Subgroup

Computer Code: CGAG Preferred Map Code: CGA
Status Code: Full
Age range: Mid Pleistocene (QPM) — Mid Pleistocene (QPM)
Lithological Description: Sandy diamictons (till), sand, gravel, silt and clay. Clasts are predominantly of micaceous psammite, mica schist, granite and granodiorite. Mainly deposited from ice that radiated away from an ice-divide centred over Rannoch Moor.
Definition of Lower Boundary: Unconformable contact with bedrock.
Definition of Upper Boundary: Unconformably overlain by units of the Central Grampian Glacigenic Subgroup.
Thickness: Up to 10 m.
Geographical Limits: The Grampian Highlands bounded by the Great Glen and Moray Firth to the north, the Cairngorms and Gaick Plateau to the east, Strathmore to the south, and including the Inner Hebrides lying to the south of Mull.
Parent Unit: Albion Glacigenic Group (ALBI)
Previous Name(s): Central Grampian Drift Group [Obsolete Name and Code: Use IAG] (-772)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  1:50 000 BGS Sheet (Scotland) 63E (Dalwhinnie). See also the stratotypes of constituent formations, including the Boyne Craig Till and Ailleag Diamicton. 
Reference(s):
McMillan, A A, Hamblin, R J O and Merritt, J W. 2005. An overview of the lithostratigraphical framework for the Quarternary and Neogene deposits of Great Britain (onshore). British Geological Survey Research Report RR/04/04. 
McMillan, A A, Hamblin, R J O, and Merritt, J W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03. 343pp. 
Merritt, J W, Auton, C A, Connell, E R, Hall, A M and Peacock, J D. 2003. The Cainozoic geology and landscape evolution of north-east Scotland. Memoir of the British Geological Survey, Sheets 66E, 67, 76E, 77, 86E, 87W, 87E, 95, 96W, 96E and 97 (Scotland) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable