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