The BGS Lexicon of Named Rock Units — Result Details
Broomhill Clay Formation
| Computer Code: | BRLL | Preferred Map Code: | BRLL |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Devensian Stage (QD) — Devensian Stage (QD) | ||
| Lithological Description: | The typical lithology is thinly bedded silty clay with wisps, laminae and bands of silt and, locally, sand. The deposit is generally reddish brown with grey or buff silt and sand. Isolated clasts up to 14cm are present and are considered to be dropstones. The deposit is of a hard to stiff consistency and medium to high plasticity. Thin diamicton bands and patches occur locally, with some graded bedding (turbidity flows) and microfaulting. Laminations are probably varves, and might represent 600 to 1000 years of sedimentation. | ||
| Definition of Lower Boundary: | Unconformity on older Quaternary strata, such as the Baillieston Till Formation, or bedrock, or a glacial deformation boundary. | ||
| Definition of Upper Boundary: | Unconformity below younger Quaternary strata or, most commonly, a glacial deformation boundary with the overlying glacial diamicton of the Wilderness Till Formation. | ||
| Thickness: | Veneer to more than 15m. | ||
| Geographical Limits: | Central Scotland, related to ice streams sourced in the Highlands (in contrast to the Southern Uplands) during the early part of the Dimlington Stadial; more specifically the Glasgow area between Erskine Bridge and Baillieston and also the western Kelvin valley. | ||
| Parent Unit: | Midland Valley Glacigenic Subgroup (MVG) | ||
| Previous Name(s): | Broomhill Clay Member [Obsolete Name and Code: Use BRLL]
(-4497)
Broomhill Member (-721) Broomhill Formation [Obsolete Name and Code: Use BRLL] (-2019) |
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| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Broomhill, central Glasgow. Browne and McMillan (1989a) | ||
| Reference Section | The Erskine Bridge Borehole (Browne and McMillan, 1989a, Figure 11) contains the standard section for the Broomhill Clay Formation (BRLL) (from 16.31 to 32.72m depth) Its stratigraphical position between the Baillieston and Wilderness till formations is clearly established here (see also ibid, Figure 3B and D). The limits of its geographical distribution are shown in ibid (Figure 2a). Browne and McMillan (1989a). | ||
| Reference(s): | |||
| 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. 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. | |||
| 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. | |||
| 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). | |||
| 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. 1989a. Quaternary geology of the Clyde valley. British Geological Survey Research Report, SA/89/1. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||