Geoscience Reference
In-Depth Information
It is also clear that the orientation and location of the coastal zones and the sub-
marine topography must reflect the erosional activity of these rivers. The way that the
southern coast runs slightly oblique to the east-west Variscan trend must reflect this
erosional history. The erosion of the Bristol Channel, Severn Estuary and Severn Val-
ley appears to be related to the river erosion of the soft sediments of the Bristol Chan-
nel and Worcester Basin, and may have caused late-stage uplift of the Cotswolds. In
the east, the coastline of the Thames Estuary and the other associated estuaries must
reflect stages in this river's erosion, probably localised, to an extent, by the downward
movement of the London downfold. Its form is very different from that of the Wash on
the other side of East Anglia, which is likely to reflect a combination of the stability of
the Midlands Platform and erosion by the Great Ouse and other Midlands rivers.
FIG
318.
Southern England and surroundings, showing main river valleys and approxim-
ate continuations at times of low sea level.
THE SHAPE, FORM AND LOCATION OF SOUTHERN
ENGLAND
What has given Southern England its 100-km-scale inland landscape features?
The presence of the resistant and deformed Variscan bedrock in the Southwest Region
has given it many distinctive landscape features, including the deformed killas slates,
the major granite bodies and the Lizard Complex, that were all formed during Episode
1 (the Variscan mountain building). However, on the 100 km scale, the present-day
shape and form of the western part of Southern England was defined during Episode
2, and it is marked particularly by the pattern of basins defined by the Lower New Red
Sandstone level.
I have to admit to having no real explanation for this pattern, except that it must
have formed as a movement response to the very varied patterns of materials in the
Earth's crust at this point. The second, the Middle Jurassic level, has given rise to a re-
latively simple scarp pattern extending from the north to the south coast, and the third,
