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The Rhynie chert is nowhere exposed naturally at the surface,
being found primarily as loose 'float' blocks in the fields. Apart from
drilling, the only means available to see the chert and interbedded sediments in
situ is to dig trenches. The photograph on the left illustrates one of a
series of trenches excavated in August 1963. Here the trench has intersected one
of the chert beds (the light coloured rock just above left of center and bottom
right) where it is interbedded mainly with dark shales and minor muddy
sandstones. The beds are dipping quite steeply to the northeast (right as
viewed).
By observing the cherts in situ we can better understand
their geometry (e.g. whether they occur as tabular beds or lenses), lateral
continuity, and distribution in relation to the sedimentary rocks in which they
occur.
Try clicking on the cherts in the picture for a close-up!
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Above: Photograph of one of the trenches dug
in 1963 showing a chert bed dipping steeply to the northeast (to the right in
photograph).
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