The BGS Lexicon of Named Rock Units — Result Details

Clyde Valley Formation

Computer Code: CLVY Preferred Map Code: notEntered
Status Code: Full
Age range: Holocene Epoch (QH) — Holocene Epoch (QH)
Lithological Description: In the Clyde valley catchment, especially the Clyde and its major tributaries, the formation consists of a wide range of lithologies encompassing pebbles, fine to coarse gravel, cobbles and boulders in a sandy matrix and coarse- to fine-grained sand, silt and clay. Beds rich in organic remains occur as well as peat (in the floodplain deposits). A partial type section is recorded in the BGS Law Borehole (Law Formation of Browne and McMillan, 1989a, 39-40 and Figure 22). The lithology here is of massive, flat laminated and also cross-bedded, grey, fine to coarse-grained sand with silt and traces of fine gravel. In the BGS Lochwinnoch Borehole (ibid, Figure 25) loose to dense, dark brownish grey, framework supported, sub-angular to rounded fine to medium gravel with sand is recorded. Bedded silt with thin peat units and organic layers are intercalated. The stratigraphical relationships of the Clyde Valley Formation (formerly Law Formation) are illustrated in ibid (Figure 3) and its geographical distribution in ibid (Figure 2e). Although the above associations for the formation are different in grain size, they are both the products of fluvial processes operating on different scales. At Law the deposits are of a minor meandering stream and at Lochwinnoch of an intermediate sized alluvial fan laterally infilling the basin in the Lochwinnoch Gap.
Definition of Lower Boundary: Unconformably overlies older Quaternary deposits and bedrock.
Definition of Upper Boundary: Normally the land surface.
Thickness: Veneer to several metres.
Geographical Limits: Recognized in the Clyde catchment area as the alluvial deposits of the Clyde and all its tributaries, from highest to lowest order.
Parent Unit: Clyde Catchments Subgroup (CLYCA)
Previous Name(s): Law Formation [Obsolete Name And Code: Use CLVY] (LAW)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  BGS Law Borehole, Castlehill Ridge, Law. Registered no. NS85SW/436. 
Type Area  Clyde Catchment. 
Reference(s):
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. 
Browne, M A E and McMillan, A A. 1989a. Quaternary geology of the Clyde valley. British Geological Survey Research Report, SA/89/1. 
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. 2005. A provisional Quaternary and Neogene lithostratigraphical framework for Great Britain. (Netherlands: Journal of Geosciences), 84-2, 87-107. 
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