The sand and gravel resources of the country between Bourne and Crowland, Lincolnshire : description of 1:25,000 sheet TF 11 and parts of 01 and 21

The geological maps of the Institute of Geological Sciences, pre-existing borehole information, and 161 boreholes drilled for the Industrial Minerals Assessment Unit form the basis of the assessment of the sand and gravel resources of the country between Bourne and Crowland, Lincolnshire. be potentially workable for sand and gravel have been investigated and a simple statistical method has been used to estimate the volume. The accompanying 1:250 00 map is divided into six main resource blocks. The geology of the deposits is described and the mineral-bearing areas within each block are distinguished by sub-blocks. The mean thicknesses of overburden and mineral and the mean gradings, together with detailed borehole data, are also given. The geological lines, cross-sections and symbols, the positions of selected non-confidential boreholes used in the assessment (and grading information for most IMAU boreholes), the outlines of the resource blocks and sub-blocks, and diagrams showing the variations of mineral thickness and bedrock surface contours are shown on the accompanying map. The principal mineral resources are First Terrace fluviatile gravels (up to 7.0 m thick) and their marine/ estuarine facies; boreholes indicate that the latter is more extensive than hitherto known. Overburden, comprising mainly silts and peat, increases in thickness towards the east and north-east. The drilling occasionally encountered a 'leaf' of the Lower Peat and confirmed the widespread but discontinuous sub-crop of Boulder Clay flooring the Fenland. All the deposits in the resource sheet area that might Bibliographical