The BGS Lexicon of Named Rock Units — Result Details

Balloch Clay Member

Computer Code: BOCH Preferred Map Code: BOCH
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Clayey silt, clay and sand, mid to dark grey, bedded and thinly laminated in places, with dark sulphide patches and fine mica; very soft to soft consistency and medium to low plasticity, isolated clasts up to 3cm (presumed dropstones), some graded units, sulphide patches, rare marine shells and plant remains.
Definition of Lower Boundary: The Ballock Clay Member of the Clyde Clay Formation rests with angular unconformity on older Quaternary sediments or bedrock. It normally rests on the Inverleven Gravel Member of the Clyde Clay Formation or possibly on the Wilderness Till Formation (WITI) of the Caledonia Glacigenic Group (Midland Valley Glacigenic Subgroup).
Definition of Upper Boundary: The Balloch Clay Member of the Clyde Clay Formation is overlain unconformably by younger Quaternary sediments, normally the Clydebank Clay Formation of the British Coastal Deposits Group but will include buried deposits belonging to the deglacial phase at the end of the Loch Lomond Stadial.
Thickness: Veneer to more than 40m.
Geographical Limits: The Balloch Clay Member of the Clyde Clay Formation is recognized in the Leven valley south of Loch Lomond.
Parent Unit: Clyde Clay Formation (CLYD)
Previous Name(s): Balloch Member (-71)
Clyde Beds (-1375)
Balloch Formation (-2005)
Alternative Name(s): none recorded or not applicable
Type Area  Leven valley south of Loch Lomond from Balloch to Dumbarton. Browne and McMillan (1989a) 
Reference Section  The BGS Inverleven Borehole. Browne and McMillan (1989a, Figure 9). 
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. 
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. 
Jardine, W G (Editor). 1980. Glasgow Region: Field Guide. [Quaternary Reseach Association.] 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable