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| Carboniferous Period |
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| Age : |
290 – 354 million
years ago |
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| Geography, environment
and climate |
The start of the Carboniferous
was marked by a major rise in sea-level which covered almost
all of England and Wales. A gradual shallowing of the sea and
formation of extensive deltas feeding from a landmass to the
north (Scotland) led to the establishment of terrestrial conditions
by the end of the Period.
A tropical climate predominated with the British Isles occupying
an equatorial location. |
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| Key Events |
The shallow tropical
seas of the Lower Carboniferous were rich in marine life, particularly
corals, brachiopods and trilobites. On land dense forests of
ferns and horsetails grew on low-lying deltas during the Upper
Carboniferous. The buried remains of these forests now form
the coal beds found in the Coal Measures of the midlands and
northern England.
Towards the end of this period the coming together of tectonic
plates to form a supercontinent known as Pangea, led to a major
phase of mountain building (the Variscan Orogeny). The main
mountains were formed in Europe, but southern Britain felt the
force of the collision, which produced spectacular folds in
the Devonian and Carboniferous rocks along the north Devon coast
at Hartland Quay. The deformative pressure reduced northwards
and more gentle folds formed the Mendip Hills. Associated with
this period of mountain-building was the intrusion of the granites
found in south-west England and the attachment of the serpentinite
of the Lizard Peninsula, a small piece of ocean crust which
was pushed up and ‘welded’ onto the continental
landmass. |
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| Rock types and occurrence
in England |
| Marine limestones (the
Carboniferous Limestone) deposited during the Lower Carboniferous
now outcrop widely forming the Mendip Hills, Avon Gorge, Derbyshire
Peak district, the Yorkshire and Northumberland Dales. The overlying
Millstone Grit forms upland areas in the Midlands and northern
England (Peak District, Pennines, Forest of Bowland) while the
Upper Carboniferous Coal Measures outcrops adjacent to the Millstone
Grit, but forming lower-lying land, from Bristol, northwards
to Cumbria and across to County Durham. |
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