Geoscience Reference
In-Depth Information
FIG
156.
Map showing the main fold trends and faults of Area 8, and the areas underlain
by bedrock of Carboniferous age or older. Landscapes
A
to
F
are also marked, along
with localities (
a1, a2
etc.) mentioned in the text.
This Landscape's Bristol Channel coastline runs approximately from west to east
and is a continuation of the Exmoor coast (see Area 3). Both run parallel to - and have
been controlled by - the main Variscan folds. Hinkley Point (
a2
) is notable as the site
of two nuclear power stations, one of which is in the process of being decommissioned.
The intertidal zone of this stretch of coastline consists largely of a wave-cut bedrock
platform, exposed to view at low water on medium tides. Most of the bedrock is Early
Jurassic in age and consists of grey mudstone with a clear, regular layering of thin
limestones. Examination of the layering shows that this bedrock has been folded loc-
ally and fractured by numerous faults that trend east-west. Because these movements
have deformed the Jurassic bedrock, they must have occurred distinctly later than the
mountain-building episode represented by the Variscan Unconformity, and may have
formed during the creation of the Bristol Channel Basin (Fig. 153).
FIG
157.
Main river pathways and coastal flooding zone of Area 8.
A narrow beach of sand and mud is present along much of this coastline at the
upper limit reached by normal high tides. Inland from this, there is generally a small
