| Computer Code: |
CLYD |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Devensian Stage (QD)
— Devensian Stage (QD) |
| Lithological Description: |
The Clyde Clay Formation has six members, from oldest to youngest - the Bridgeton Sand consists of beds of fine- to medium-grained sand, and sandy fine to coarse gravel in an upward-fining succession. The Paisley Clay consists of clays and silts, finely colour banded in shades of greyish brown, grey and reddish brown. The Linwood Clay consists of thickly bedded to massive silts, clayey silts and silty clays, medium to dark grey becoming brownish grey downwards, with sand layers, black sulphide bands and many marine shells. The Killearn Sand and Gravel is commonly reddish brown and yellow, fine- to medium-grained sand with clay layers and beds of gravel. The Inverleven Gravel typically is angular to subrounded boulders, cobbles and gravel in a clayey sand matrix with barnacles. The Balloch Clay consists of clayey silt, silt, clay and sand, mid to dark grey, brownish grey and locally reddish brown, bedded and thinly laminated, normal and reverse graded units, with dark sulphide patches and rare marine shells. Their stratigraphical relationships and geographical distribution are summarized in Browne and McMillan, 1989a, Figures 2b, c and d, 3A, B, C and D and 4A, B and C.) |
| Definition of Lower Boundary: |
The Clyde Clay Formations rests with angular unconformity on older Quaternary sediments or bedrock. It normally rests on the Wilderness Till Formation (WITI) of the Caledonian Glacigenic Group (Midland Valley Glacigenic Subgroup). |
| Definition of Upper Boundary: |
The Clyde Clay Formation 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 Catchment Subgroup). It is also extensively exposed at surface in the lower Clyde valley. |
| Thickness: |
Veneer to more than 50m. |
| Geographical Limits: |
The Clyde Clay Formation is recognised in the lower Clyde valley north of Lanark, in and around the estuary of the Clyde and Firth of Clyde and linked sea lochs, and in Loch Lomand. It is also present under the coastal plain of Ayrshire. |
| Parent Unit: |
British Coastal Deposits Group (COAS)
|
| Previous Name(s): |
Clyde Beds [Obsolete Name and Code: Use PRTS, BOCH, LIWD, PAIS, KARN, CLYD]
(-1375)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Geilston Burn, valley side exposures, by Cardross, Clyde estuary. |
| 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. |
| 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). |
| Paterson, I B, McAdam, A D and MacPherson, K A T. 1998. Geology of the Hamilton district. Memoir of the British Geological Survey, Sheet 23W (Scotland). |
| Browne, M A E, and McMillan, A A. 1989a. Quaternary geology of the Clyde valley. British Geological Survey Research Report, SA/89/1. |
| Jardine, W G (Editor). 1980. Glasgow Region: Field Guide. [Quaternary Reseach Association.] |
| 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). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
