The BGS Lexicon of Named Rock Units — Result Details

Clyde Catchments Subgroup

Computer Code: CLYCA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Holocene Epoch (QH)
Lithological Description: Includes the fluvial deposits of the River Clyde and its tributaries. The deposits include alluvium and river terrace deposits of the Clyde Valley Formation and fluvial deposits of the Strathendrick Formation and other units defined simply by lithogenetic categories. The deposits of the subgroup comprise gravel, sand, silt, peat and head. Rock types found in clasts are principally of Carboniferous and Devonian strata (sandstone, siltstone) with volcanic (basalt) and intrusive igneous rocks (microdiorite) of Midland Valley provenance. Variable but generally minor components of Dalradian metasedimentary and Caledonian igneous rocks derived from the Grampian Highlands are present. Southern Uplands sourced greywacke sandstone and siltstone and Caledonian igneous rocks form a component of clastic fluvial deposits in parts of catchments close to the Southern Uplands. A suite of fluvial (alluvium and river terrace deposits) and associated organic and lacustrine sediments that contain clasts derived from Palaeozoic rocks and glacigenic deposits cropping out in the catchment of the River Clyde and other rivers flowing directly to the Firth of Clyde, including the River Leven, and Waters of Girvan, Ayr and Irvine. Devensian to Holocene (MIS 2-1).
Definition of Lower Boundary: Unconformable contacts with units of the Midland Valley, Mearns, Central Grampian and Southern Uplands Glacigenic subgroups, and bedrock.
Definition of Upper Boundary: Generally the ground surface, but units of this Subgroup interfinger locally with units of the British Coastal Deposits Group.
Thickness: Up to 25 m.
Geographical Limits: The present physical catchments of the rivers Clyde, Kelvin, Endrick and the rivers of Ayrshire. The catchments extend across Strathclyde, (Ayrshire, Lanarkshire and Dumbartonshire).
Parent Unit: Britannia Catchments Group (BCAT)
Previous Name(s): Girvan Formation [Obsolete Name and Code: Use CLYCA] (-3945)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
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. 
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. 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. 
McMillan, A A. 2005. A provisional Quaternary and Neogene lithostratigraphical framework for Great Britain. (Netherlands: Journal of Geosciences), 84-2, 87-107. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable