The BGS Lexicon of Named Rock Units — Result Details
Mangotsfield Member
| Computer Code: | MGF | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Bolsovian Substage (CC) — Bolsovian Substage (CC) | ||
| Lithological Description: | Predominantly cross-bedded, lithic arenite, 'Pennant' sandstone in the lower part, and an upper part with thick grey fissile mudstone beds interbedded with sandstone and sparse coal seams (Kellaway and Welch, 1993). The sandstone weathers to a distinctive red to purple colour. The sandstones formed in channels and floodplains within a broad alluvial tract, with palaeocurrents toward the north and north-west (Cleal and Thomas, 1996). A poor record of Alethopteris serlii Subzone macroflora is listed by Cleal (1997) suggesting a late Bolsovian age. | ||
| Definition of Lower Boundary: | Base of the lowermost lithic arenite 'Pennant' sandstone of the Mangotsfield Member, resting sharply upon the Mangotsfield Coal, present at the top of the Downend Member. | ||
| Definition of Upper Boundary: | Top of member is taken at the top of the Rudge Vein Coal in the Somerset Coalfield; top of the High Vein Coal in the Bristol Coalfield; top of the Avonmouth No. 2 Coal in the Severn Coalfield. Overlain by grey mudstone of the Farrington Member. | ||
| Thickness: | Up to c. 580 m at Iron Acton [ST 67 84] to Engine Common [ST 70 84]; 450 m proved in the type area. | ||
| Geographical Limits: | Bristol, Somerset and Severn coalfields. | ||
| Parent Unit: | Pennant Sandstone Formation (PES) | ||
| Previous Name(s): | Mangotsfield Formation [Obsolete Name and Code: Use MGF]
(-1692)
Mangotsfield Group [Obsolete Name and Code: Use MGF] (-4793) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Mangotsfield, Avon [ST 65 77]: parts of the member are exposed along the River Frome and quarries between Frenchay [ST 641 772] and Hambrook [ST 645 788] (Kellaway and Welch, 1993). | ||
| Type Section | Winterbourne railway cutting, Avon [ST 651 799]: 200 m thick succession (Cleal and Thomas, 1996). | ||
| Reference(s): | |||
| Cleal, C and Thomas, B A. 1996. British Upper Carboniferous stratigraphy. Geological conservation review series No. 11. [London: Chapman and Hall]. | |||
| Kellaway, G A. 1969. The Upper Coal Measures of South-West England compared with those of South Wales and the Southern Midlands. Compe Rendu 6e Congres Internationale Stratigraphie et Geologie Carbonifere, Sheffield, 1967, Vol. 3, 1039-1055. | |||
| Kellaway, G A and Welch, F B A. 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. | |||
| 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. | |||
| Cleal, C J. 1997. The palaeobotany of the upper Westphalian and Stephanian of southern Britain and its geological significance. Review of Palaeobotany and Palynology, Vol. 95, 227-253. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E250 E251 E281 E264 E280 | |||