The sand and gravel resources of the country around Prees, Shropshire : description of 1:25,000 sheet SJ 53

The geological maps of the Institute of Geological Sciences, pre-existing borehole information, and 88 boreholes drilled for the Industrial Minerals Assessment Unit form the basis of the assessment of the sand and gravel resources of the country around Prees, Shropshire. All the deposits in the district that might be potentially workable for sand and gravel have been investigated and a simple statistical method has been used to estimate the volume. The reliability of the volume estimates is given at the symmetrical 95 per cent probability level. The 1:25 000 map is divided into six resource blocks, containing between 9.1 and1 6.5 km2o f potentially workable sand and gravel. For each block the geology of the deposits is described, and the mineral-bearing area, the mean thickness of overburden and mineral and the mean gradings are stated. Detailed borehole data are also given. The geology, the position of the boreholes and the outlines of the resource blocks are shown on the accompanying map. As a result of this survey, the line of the Wem fault shown on the published one-inch map (sheet 138) has been realigned up to 0.7km north-westwards, and a previously unknown subcrop, beneath drift, of Northwich Halite (Lower Keuper Saliferous Beds) probably exists south-east of this fault. Extensive deposits of laminated clay, with rhythmite sequences in part, occur beneath the outwash plain of Prees Heath.