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Climate
change
With the present major concerns over climate change, with predicted
higher temperatures and rising sea-levels, believed to be induced
by man’s recent activities, anything we can find out
about past climate change before man’s influence, is
very important. Study of the flora and fauna contained within
some of the most recent sediments can provide a real insight
into how the climate in Britain has fluctuated during the last
1.8 million years. Quarries can provide good sequences and
importantly, a source of fresh, un-weathered material to work
on.
Many of the important interglacial sites in Britain have been
identified in quarries. These have often provided rich sources
for bones of exotic mammals such as elephant and hippopotamus.
At the other end of the scale, fragments of fossil beetles
which can provide extremely detailed information on the nature
of the climate and local vegetation at the time of deposition.
Smaller still, pollen and spores contained within these sediments
can also be used as an indicator of past climate. The age of
interglacial deposits can be determined using a variety of
dating techniques such as radiocarbon, luminescence, and uranium
series.
Microscopic image of beetle remains.
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Collecting samples from an interglacial site.
Tills (boulder clays), deposited by the ice sheets that once
covered Britain during very cold periods, are often present
as overburden in both hard-rock and sand and gravel quarries.
The orientation of the pebbles within the till provides evidence
of the direction of ice travel. The composition of the pebbles
in the till provides clues about the bedrock formations over
which the ice travelled. Detailed study of the till can reveal
whether it was deposited on land or in water.
Example of boulder clayy (till), northern
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