The Oxfordshire Coalfield

Abstract

THE discovery of eight coal seams of workable quality in the Geological Survey Apley Barn Borehole^1,2, sunk in 1960–61 near Witney, prompted the recent sinking of a second borehole (1970–71) near Steeple Aston, Oxfordshire. This borehole is situated between Bicester and Chipping Norton some 14 miles north-east of the Apley Barn Borehole (Fig. 1). The exact site is 825 yards (750 m) at 254° from St Peter's Church, Steeple Aston (National Grid Reference SU 4687 2586). The geophysical Bouguer anomaly gravity contour map shows that the borehole lies in the eastern part of a low density area where a thick sequence of light sedimentary rocks could be expected. It was thought possible that this anomaly could be due to a thickening of the Coal Measures sequence as a whole and that perhaps even Middle Coal Measures (with valuable coal seams) could be developed. In the event, however, this hope has not been realized, and although Upper Coal Measures were proved the borehole has shown that the low density anomaly feature must be due to a thickening of Devonian and/or older sediments.