| Computer Code: |
WITI |
Preferred Map Code: |
WITI |
| Status Code: |
Full |
| Age range: |
Devensian Stage (QD)
— Devensian Stage (QD) |
| Lithological Description: |
The typical lithology is a glacially organized diamicton composed of isolated boulders, cobbles, gravel and pebbles in a matrix of sandy silty clay. The more elongate clasts are preferentially oriented and the deposits usually has systematic sets of joints. It is of a hard to stiff consistency and low plasticity. The colour varies, depending upon that of the local bedrock and can be reddish brown (Devonian and Upper Coal Measures), brownish grey or black (Carboniferous) and also greenish grey (Highland Metamorphic rocks). Minor features include pockets and bands of medium-grained sand and laminated clay bands up to 10cm thickness. The the Cadder area, temporary sections revealed that the diamicton is locally graded, displaying both upward and downward coarsening of the dispersed pebble to boulder sized clasts. At Baillieston (ibid, Figure 13), the till showed slices of laminated clay, one of considerable size (tens of metres), including near the base of the formation and sandwiched between two dicordant planes, which are likely to be low angle thrusts. |
| Definition of Lower Boundary: |
Unconformity or glacial deformation boundary on bedrock or on older Quaternary strata, e.g. the Cadder Sand Formation. |
| Definition of Upper Boundary: |
Unconformity below younger Quaternary strata, or a glacial deformation boundary that is partly represented by the upper surface of drumlinoid landforms. These landforms are commonly seen at surface but might also form buried features in the Glasgow conurbation. |
| Thickness: |
Veneer to over 30m |
| Geographical Limits: |
Central Scotland, related to ice streams sourced in the Highlands (in contrast to the Southern Uplands) during the Dimlington Stadial; Glasgow area, Stirling, Clackmannan, Tayside, north and south Lanarkshire, Lothians and Edinburgh, Fife. |
| Parent Unit: |
Midland Valley Glacigenic Subgroup (MVG)
|
| Previous Name(s): |
Wilderness Member
(-611)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
BGS Bellshill Borehole. Browne and McMillan, 1989a. |
| Type Section |
Temporary sections at Wilderness Plantation north of Bishopbriggs. Rose et al., 1988. |
| Reference(s): |
| 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). |
| 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. |
| Bowen, D Q. 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, No. 23. |
| Cameron, I B, Aitken, A M, Browne, M A E and Stephenson, D. 1998. Geology of Falkirk District. Memoir of the British Geological Survey Sheet 31E (Scotland). |
| 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). |
| Jardine, W G (Editor). 1980. Glasgow Region: Field Guide. [Quaternary Reseach Association.] |
| Rose, J, Lowe, J J and Switsur, R. 1988. A radiocarbon date on plant detritus beneath till from the type area of the Loch Lomond Readvance. Scottish Journal of Geology, Vol.24, 113-124. |
| 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. |
| 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). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
