The BGS Lexicon of Named Rock Units — Result Details
Swansea Member
| Computer Code: | SW | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Asturian Substage (CAS) — Asturian Substage (CAS) | ||
| Lithological Description: | Green-grey, lithic arenites ('Pennant sandstones') with thin mudstone, siltstone and seatearth interbeds, and mainly thin coals. Age Asturian. | ||
| Definition of Lower Boundary: | The base is placed at the base of the Golden (Swansea Three-Feet or Graigola) Coal (Woodland et al., 1957), underlain conformably by sandstone and thin mudstone and siltstone of the Hughes Member. | ||
| Definition of Upper Boundary: | The top is placed at the base of the Wernffraith Seam (correlated with the Mynyddislwyn Seam of the eastern part of the South Wales Coalfield) overlain conformably by the mudstone-dominated succession of the Grovesend Formation. | ||
| Thickness: | From 274 m to 290 m. | ||
| Geographical Limits: | Western part of the South Wales Coalfield, from Llanelli [SN 49 01] to the Neath area [around SS 75 97]. | ||
| Parent Unit: | Pennant Sandstone Formation (PES) | ||
| Previous Name(s): | Swansea Formation [Obsolete Name and Code: Use SW]
(-3704)
Swansea Beds [Obsolete Name and Code: Use SW] (-4911) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | There is no designated stratotype, the Member being named from the Swansea district (Woodland et al., 1957). Allt-y-fran Quarry [SN 5136 0143], Tyrfran, Llanelli provides a reference section in which 9.9 m of mudstones and siltstones overlie 'Pennant' sandstones (Barclay, 2011). | ||
| Reference(s): | |||
| 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. | |||
| Barclay, W J. 2011. Geology of the Swansea district: a brief explanation of the geological map. Sheet Description of the British Geological Survey. 1:50 000 Sheet 247 Swansea (England and Wales). | |||
| Woodland, A W, Evans, W B and Stephens, J V. 1957. Classification of the Coal Measures of South Wales with Special reference to the Upper Coal Measures. Bulletin of the Geological Survey of Great Britain, No. 13, 39-60. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E247 E230 E246 E248 | |||