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The South Yorkshire Coalfield is so named from its position within Yorkshire. It covers most of South Yorkshire, West Yorkshire and a small part of North Yorkshire. The exposed coalfield outcrops in the Pennine foothills and dips under Permian rocks in the east. Its most famous coal seam is the Barnsley Bed. Coal has been mined from shallow seams and outcrops since medieval times and possibly earlier. == Geography and geology == The coalfield stretches from Halifax in the north west, to the north of Bradford and Leeds in the north east, Huddersfield and Sheffield in the west, and Doncaster in the east. The major towns of Wakefield, Barnsley and Rotherham are within its boundaries. It is part of the larger Nottinghamshire, Derbyshire and Yorkshire Coalfield. Its western boundary is defined by the outcropping of coal seams in the foothills of the Pennines and in the east by the descent of the coal-bearing strata under overlying rocks as they approach the North Sea. Since the creation of the county of South Yorkshire in 1974, the name can be misleading as the coalfield stretches beyond the Wakefield district and other parts of West Yorkshire as far as Keighley and Kellingley Colliery and the Selby Coalfield are in North Yorkshire. It is separate from the Ingleton Coalfield in North Yorkshire, and a small number of mines around Todmorden are part of the Lancashire Coalfield.〔(Northern Mine Research Society - Mines of coal and other stratified minerals in Yorkshire from 1854 )〕 The coal bearing rock strata or coal measures that make up the coalfield outcrop in foothills of the Pennines and dip gently downwards from west to east. This area is known as the exposed coalfield. The coal measures are carboniferous rocks laid down between 290 and 354 million years ago. West and east of Doncaster the coal measures are overlain by younger rocks, permian limestone,〔BGS, Barnsley, p. 1〕 where the area is referred to as the concealed coal field.〔Hill, South Yorkshire Coalfield, p. 14〕 The northernmost extent of the South Yorkshire Coalfield is marked by the change of the fields richest and highest grade coal seam, the Barnsley Seam or Bed, to a thin seam of inferior coal. This occurs to the north of Barnsley.〔 The southern limit was marked by the Barnsley Bed losing its coking qualities.〔Hill, South Yorkshire Coalfield, p. 22〕 The structure of the coal field is not significantly affected by faults except along the River Don between Sheffield and Mexborough. These faults give rise to the Frickley and Maltby troughs where the coal measures are thrown down and lie deeper than other parts of the coalfield. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「South Yorkshire Coalfield」の詳細全文を読む スポンサード リンク
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