The BGS Lexicon of Named Rock Units — Result Details

Clydebank Clay Formation

Computer Code: CBCL Preferred Map Code: notEntered
Status Code: Full
Age range: Holocene Epoch (QH) — Holocene Epoch (QH)
Lithological Description: The Clydebank Clay Formation comprises mainly clay and silt, with subsidiart sand and gravel deposits, forming four members (q.v.): from oldest to youngest these are the Buchanan Clay, Longhaugh Sand and Gravel, Erskine Clay and Gourock Sand members. More detail of the lithologies of the individual members is included in the related Lexicon entries.
Definition of Lower Boundary: The Clydebank Clay Formation rests with angular unconformity on older Quaternary sediments or bedrock. It most commonly rests on the Wilderness Till Formation (WITI) of the Caledonia Glecigenic Group (Midland Valley Glacigenic Subgroup).
Definition of Upper Boundary: The Clydebank Clay Formation is overlain unconformably by younger Quaternary sediments, normally either the Clippens Peat Formation or Clyde Valley Formation of the Clyde Catchment Subgroup (Britannia Catchments Group). It is also extensively exposed at surface in the lower Clyde valley.
Thickness: Ranges from a veneer to more than 15m.
Geographical Limits: The Clydebank Clay Formation is recognised in the lower Clyde Valley north of Lanark, in the estuary of the Clyde, and in Loch Lomond.
Parent Unit: British Coastal Deposits Group (COAS)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Lower Clyde valley, Clyde Estuary and Loch Lomond. The NGR values provided are the southwest and northeast corners of a conceptual rectangle that approximates to the Type Area, and should be considered a rough guide only to the lateral extent of the Formation. 
Reference(s):
Bowen, D Q. 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, No. 23. 
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. 
Browne, M A E and McMillan, A A. 1989a. Quaternary geology of the Clyde valley. British Geological Survey Research Report, SA/89/1. 
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. 
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable