The BGS Lexicon of Named Rock Units — Result Details

Linwood Clay Member

Computer Code: LIWD Preferred Map Code: LIWD
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: The typical lithologies are clayey silt and clay, mid grey, micaceous, very soft to soft consistency, firm with depth, medium to low plasticity and low plasticity index; sand is present especially at and near the top, in layers up to 3cm thick, with isolated stones of up to 2cm; seaweed and other plant remains are present together with foraminifera (Elphidium clavatum) and marine shells. Sequence at the base is thickly bedded to massive.
Definition of Lower Boundary: The Linwood Clay Member of the Clyde Clay Formation rests with angular unconformity and conformity on older Quaternary sediments or bedrock. It normally rests conformably on the Paisley Clay Member of the Clyde Clay Formation or unconformably on the Wilderness Till Formation (WITI) of the Caledonia Glacigenic Group (Midland Valley Glacigenic Subgroup).
Definition of Upper Boundary: The Linwood Clay Member is overlain unconformably by younger Quaternary sediments, normally either the Clydebank Clay Formation of the British Coastal Deposits Group or the Clippens Peat Formation or Clyde Valley Formation of the Britannia Catchments Group (Clyde Catchments Subgroup). It passes upwards and laterally into the Killearn Sand and Gravel Member in some localities but in others is erosively overlain by the same unit. It is also extensively exposed at surface in the Lower Clyde valley below Shieldhall and in the low ground around Paisley and Linwood.
Thickness: Veneer to more than 35m.
Geographical Limits: Recognised in the lower Clyde valley downstream from western Glasgow, in the Paisley-Linwood lowlands, in the estuary of the Clyde and Firth of Clyde and linked sea lochs, and in Loch Lomond. It is also present under the coastal plain of Ayrshire. (The use of this term in other estuaries such as the Forth, Tay and Earn on the east coast of Scotland awaits later consideration).
Parent Unit: Clyde Clay Formation (CLYD)
Previous Name(s): Clyde Beds (-1375)
Linwood Formation (-4763)
Alternative Name(s): none recorded or not applicable
Reference Section  BGS Linwood Borehole contains the standard section for the Linwood Clay Member (LIWD) (2.64 to 26.5m depth). Browne and McMillan (1989a, Figure 17). 
Type Area  Geilston Burn vwlley side exposures, by Cardross, Clyde estuary. 
Browne, M A E and McMillan, A A. 1989a. Quaternary geology of the Clyde valley. British Geological Survey Research Report, SA/89/1. 
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Aidrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). 
Bowen, D Q. 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, No. 23. 
Browne, M A E and McMillan, A A. 1989b. Geology for land use planning: drift deposits of the Clyde valley Volume 1: Planning Report. British Geological Survey Technical Report, WA/89/78. 
Hall, I H S, Browne, M A E and Forsyth, I H. 1998. Geology of the Glasgow district. Memoir of the British Geological Survey, Sheet 30E (Scotland). 
Jardine, W G (Editor). 1980. Glasgow Region: Field Guide. [Quaternary Reseach Association.] 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable