| Permian Period |
| |
| Age : |
248 – 290 million
years ago |
| |
| Geography, environment
and climate |
| Britain formed part
of Pangea, a landmass comprising all of the major continents.
Desert conditions prevailed over much of Pangea, which lay near
the Equator. An inland sea (the Zechstein Sea) occupied much
of the area that is now the North Sea. |
| |
| Key Events |
| At the end of the Permian
a mass extinction took place when three quarters of known species
of land animals and 96% of marine animals became extinct. Groups
such as the trilobites disappeared forever. |
| |
| Rock types and occurrence
in England |
Sandstones formed from
desert sand dunes can be found across England from Dawlish in
south Devon to County Durham. Erosion of the uplifted mountain
areas (e.g. Dartmoor) led to the deposition of thick fans of
sediment along their flanks. This material now forms the cemented
breccias of East Devon and Worcestershire.
Shallow marine limestones and associated evaporites (salts)
deposited in the Zechstein Sea now form the Magnesian Limestone.
This outcrops in a narrow band from Nottinghamshire, through
central England to the Durham coast. |
 |
