A depositional model for the Mid-Westphalian A to late Westphalian B coal measures of South Wales

Mid-Westphalian A to late Westphalian B sediments of the South Wales Coalfield comprise mainly lacustrine, raised mire and flood deposits developed in an upper coastal plain environment. Occasional high sinuosity, fine-grained channel systems drained the subdued topography of the Wales-Brabant Massif to the north and east of the basin. Low sinuosity channels with lithic, coarse-grained fills drained a rising source to the south. Direct marine influence was restricted to a single marine band. Facies distributions were controlled by: 1) local scale (10²-10³ m²) autocyclic sedimentary processes, 2) regional scale (10 km²) synsedimentary fault activity and differential subsidence, and 3) basin-wide scale (10²km²) response to changes in relative sea-level. -from Author