The sand and gravel resources of the country south-east of Norwich, Norfolk : description of 1:25,000 resource sheet TG 20

The geological maps of the Institute of Geological Sciences, pre-existing borehole information and seventy-three boreholes drilled specifically for assessment purposes (of which sixty-one were part of a feasibility study conducted in 1966-67 and twelve were drilled subsequently) form the basis of the assessment of sand and gravel resources in the Maldon area, Essex. All deposits in the area which might be potentially workable for sand and gravel (mineral ) have been investigated geologically and a simple statistical method has been used to estimate the volume. The reliability of the volume estimates is given at the 95 per cent confidence level. The 1:25 000 map is divided into resource blocks, each ideally containing approximately 10 km2 of sand and gravel. For each block the mineral bearing area, the mean thickness of overburden and mineral, and the mean grading are given and the geomorphology and geology of the deposits described. The position of the boreholes and exposures, the geology and topography and the outlines of the blocks are shown on the accompanying map TL 80. Detailed borehole data are given.