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Sand
and gravel quarries
Many quarries have been excavated in sand and gravel deposited
within the last 1.8 million years or so by rivers, glaciers
or by the sea. Exposures within such quarries provide examples
of these types of sediments and the geological
structures that go with them.
Many sand and gravel pits in central and northern England also
expose ‘boulder clay’ (till) which was deposited
directly by glaciers during the Ice Age. These quarries can
provide us with information about where the ice flowed and
how these tills were deposited.
Within the last 1.8 million years, several relatively warm
(interglacial) periods have alternated with the glacial episodes.
Peat and organic clay was commonly deposited during these warm
periods and much of the evidence for these warmer periods has
been discovered within sand and gravel quarries. A number of
these sites have been designated as Sites of Special Scientific
Interest (SSSI) in order to preserve the key features which
have been uncovered by quarrying. The nature of sand and gravel
quarries makes them difficult to restore whilst still maintaining
their geological interest. Within a short period of time material
will fall, or be washed down, from the higher parts of any
faces, and build up in front of the lower parts of the faces,
thus obscuring the geology. Unfortunately, any protection afforded
to the quarry face may also obstruct the feature that is being
protected! Active local Regionally Important Geological Sites
(RIGS) Groups may be able to provide help by keeping sections
clean and free from fallen debris.
Vegetation growth can cause difficulties in ensuring access
to geodiversity in former sand and gravel quarries. In such
cases, restoration schemes need to be sympathetic in balancing
the requirement to encourage biodiversity without reducing
geodiversity. |
Sand and gravel deposited by streams
running beneath glaciers.
Involving nature conservation organisations in discussions
regarding the proposed designs at an early stage in development
will identify any specific issues and potential solutions. |
