Page 70 - An Atlas of Carboniferous Basin Evolution in Northern England

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Formations (early Westphalian D), and (iii) Keele and Enville Formations (late Westphalian. Palaeogeography and facies evolution el al 1989). They are interpreted as the erosion products of Variscan nappes to
Westphalian D-early Stephanian). The Newcastle and Halesowen Formations (early Westphalian D) are locally the south of the British Isles and can be thus considered as a regional molasse
The Etruria Formation (late Westphalian C to early Westphalian D) is unconformable upon older Westphalian sediments or, in the case of the (Besly et al. 1993), but also have local provenance sourced from unroofing of
interpreted by Besly (1988) as the product of intra-Westphalian tectonic uplift, Oxfordshire Coalfield, upon Devonian and older rocks. They reflect a Lower Palaeozoic rocks (Glover & Powell 1996).
and is locally unconformable upon gently folded coals of late Westphalian B temporary return to a humid coal-forming environment and are the time It is probable that the Westphalian D was originally more extensive and that
age (e.g. the Symon unconformity in the Coalbrookdale Coalfield, central equivalents of the coal-bearing Middle Pennant Sandstone of South Wales. a thick Stephanian succession was deposited in many of the growth synclines
England). The Etruria Formation is composed of a range of facies including Provenance studies (e.g. Glover & Powell 1996) suggest a major input from the associated with inversion. Thermal modelling of the Ratcliffe-on-Soar-1
alluvial fan complexes and lateritic palaeosols (Besly 1988) that were developed Cornubian-Amorican highlands. The southerly thickening of these sediments borehole in the Widmerpool Gulf suggests deposition and erosion of some
around inversion anticlines. In central England, the Etruria Formation has a in the Oxfordshire Coalfield is interpreted to reflect the flexural subsidence of 600 m of post-Westphalian B sediments prior to basal Permian sedimentation
southerly derivation from contemporaneously uplifted parts of the London- the southern margin of the London-Brabant Massif due to crustal loading. The (Fraser 1995). However, the base Permian unconformity cuts across the late
Brabant Massif. In contrast, red beds of this age in northern England and Keele (late Westphalian D) and Enville Formations (late Westphalian D-early Carboniferous stratigraphy of northern England and much of the evidence for
Scotland are northerly derived, in common with the underlying coal-bearing Stephanian) are southerly-derived elastics of red bed facies (Besly 1988, Foster the deposition of these sediments has been removed