The BGS Lexicon of Named Rock Units — Result Details

Irish Sea Coast Glacigenic Subgroup

Computer Code: ISCG Preferred Map Code: ISC
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Diamicton, gravel, sand, silt and clay, typically reddish brown and containing clasts of red and yellow sandstone, greywacke sandstone and siltstone, granite and granodiorite. Welded tuff (Borrowdale Volcanic Group), mudstone, coal, shell fragments and reworked marine microfossils are common to the south of the Solway Firth.
Definition of Lower Boundary: Unconformable on bedrock.
Definition of Upper Boundary: Ground surface or unconformably overlain by Flandrian deposits.
Thickness: 50m
Geographical Limits: Cheshire, Lancashire, North Wales, western Cumbria and the Solway Lowlands.
Parent Unit: Caledonia Glacigenic Group (CALI)
Previous Name(s): Irish Sea Drift (-980)
West Cumbria Drift Group [Obsolete Name And Code: See ISCG] (WCDR)
Alternative Name(s): none recorded or not applicable
Type Area  The deposits of the Irish Sea Coast Glacigenic Subgroup are typically reddish brown because they are derived predominantly from Permo-Triassic "red-beds" of the Irish Sea Basin and adjacent basins. The type areas are the Solway Firth, western Cumbria, Lancashire and North Wales. The glacigenic deposits were derived from southwest Scotland, the Solway Lowlands, the Cumbrian mountains and the west Cumbrian coast. The deposits were laid down from ice that flowed around the north-western side of the Lake District merging with ice that flowed southwards across the Irish Sea basin from southern Scotland. The Subgroup subsumes the West Cumbria Drift Group defined in Akhurst et al. (1997) and Merritt and Auton (2000). See also stratotypes for the Gretna Till Formation, Gosforth Glacigenic Formation, Aikbank Farm Glacigenic Formation and the Seascale Glacigenic Formation and others. 
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. 
Merrit, J W and Auton, C A. 2000. An outline of the lithostratigraphy and depositional history of Quaternary deposits in the Sellafield district, west Cumbria. Proceedings of the Yorkshire Geological Society, Vol.53, 129-154 
Trotter, F M and Hollingworth, S E, 1932. The glacial sequence in the North of England. Geological Magazine, Vol.69, 374-380. 
Akhurst, M C, Chadwick, R A, Holliday, D W, McCormac, M, McMillan, A A, Millward, D, Young, B, Ambrose, K, Auton, C A, Barclay, W J, Barnes, R P, Beddoe-Stephens, B, James, J C W, Johnson, H, Jones, N S, Glover, B W, Hawkins, M P, Kimbell, G S, MacPherson, K A T, Merritt, J W, Milodowski, A E, Riley, N J, Robins, N S, Stone, P and Wingfield, R T R. 1997. The geology of the west Cumbria district. Memoir of the British Geological Survey, Sheets 28, 37 and 47 (England and Wales). 138pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable