The BGS Lexicon of Named Rock Units — Result Details
Scottish Coal Measures Group
| Computer Code: | CMSC | Preferred Map Code: | CMSC |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Langsettian Substage (CA) — Asturian Substage (CAS) | ||
| Lithological Description: | The Scottish Coal Measures Group (Browne et al., 1999, fig. 7) (fluviodeltaic ('Coal Measures') facies) is divided, in ascending sequence, into Scottish Lower, Middle and Upper Coal Measures formations. Lithologically the group comprises repeated cycles of sandstone and mudstone with coal and seatearth, arranged in both upward-fining and upward-coarsening units. The strata are generally grey in colour but are extensively reddened towards the top. A wide range of alluvial and lacustrine environments of deposition is represented. These include wetland forest and soils (coal and seatrock), floodplain (planty or rooted siltstone and mudstone), river and delta distributary channel (thick sandstones), prograding deltas (upward-coarsening sequences) and shallow lakes (mudstones with nonmarine faunas). Marine bands are rare but provide important stratigraphical markers. Economically important coal seams are common in the Lower and Middle Coal Measures, some of which can be correlated between coalfields. The group is Langsettian to Asturian (Westphalian D) in age. | ||
| Definition of Lower Boundary: | The base of the group in the Midland Valley of Scotland is now taken at the base of the Lowstone Marine Band, its local correlative, or at a plane of disconformity. This is at a slightly higher stratigraphical level than in England and Wales, where the lower boundary lies at the base of the Subcrenatum Marine Band at the base of the Langsettian (Westphalian A) Stage. This horizon has not been recognised in Scotland though it may correlate with one of the higher marine bands of the Passage Formation (No. 6) and with the Porteous Marine Band of the Douglas Coalfield. | ||
| Definition of Upper Boundary: | An unconformity of regional extent beneath Permian strata marks the top of the Scottish Coal Measures Group in the Midland Valley of Scotland. | ||
| Thickness: | The thickness of the group probably exceeds 1790 m in the Midland Valley of Scotland. | ||
| Geographical Limits: | The Scottish Coal Measures Group occurs in the Midland Valley of Scotland and adjacent areas including Sanquhar, Thornhill, Machrihanish, Arran, Stranraer and Morvern. | ||
| Parent Unit: | Coal Measures Supergroup (COME) | ||
| Previous Name(s): | Barren Coal Measures (Upper) [Obsolete Name and Code: Use CMSC]
(-146)
Leswalt Formation [Obsolete Name and Code: Use CMSC] (LWT) Productive Coal Measures (Middle and Lower) [Obsolete Name and Code: Use CMSC] (-2104) Coal Measures Group (CM) Coal Measures Group (Scotland) [Obsolete Name and Code: Use CMSC] (-797) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Strathclyde, Lothian, Fife, Scotland. (Midland Valley of Scotland). | ||
| Reference(s): | |||
| MacGregor, A G, 1960. Division of the Carboniferous on Geological Survey Scottish Maps. Bulletin of the Geological Survey of Great Britain, No.16, 127-130. | |||
| Stubblefield, C J and Trotter, F M, 1957. Divisions of the Coal Measures on Geological Survey Maps of England and Wales. Bulletin of the Geological Survey of Great Britain, No.13, p.1-5. | |||
| Waters, C N, Waters, R A, Barclay, W J, and Davies, J R. 2009. Lithostratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/09/01. 184pp. | |||
| Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. | |||
| Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) | |||
| Browne, M A E, Dean, M T, Hall, I H S, McAdam, A D Monro, S K, and Chisholm, J I. 1999. A lithostratigraphical framework for the Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Research Report RR/99/07. | |||
| 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). | |||
| Wagner, R H. 1983. A lower Rotliegend flora from Ayrshire. Scottish Journal of Geology, Vol.19, 135-155. | |||
| Waters, C N, Browne, M A E, Dean, M T and Powell, J H. 2007. Lithostratigraphical framework for Carboniferous successions of Great Britain (Onshore). British Geological Survey Research Report, RR/07/01. | |||
| Ramsbottom, W H C, Calver, M A, Eagar, R M C, Hodson, F, Holliday, D W, Stubblefield, C J and Wilson, R B. 1978. A correlation of the Silesian rocks in the British Isles. Geological Society of London, Special Report No.10. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S015 S006 S011 S338 S023 S033 S040 S030 S039 S044 | |||