Geoscience Reference
In-Depth Information
This Area, centred on the Thames Estuary, represents a continuation of the Lon-
don Basin downfold that we have examined in Areas 10 and 11, although its geometry
changes eastwards from the simple downfold structure that cradles Greater London.
The southern margin of the downfold is still clearly defined in Area 12 by the North
Downs, but the northerly Chalk margin curves off first to the northeast and then to the
north as it crosses East Anglia (see Chapter 2, Fig. 9). As a result, the northern half of
Area 12 is underlain by Early Tertiary bedrock, marking the centre of the London Bas-
in downfold. This pattern in the bedrock (Figs 213 and 214) provides the best division
for more detailed examination of local scenery, and forms the basis for dividing the
Area into four Landscapes, marked
A
to
D
in Figure 215. Whereas the main features of
the Landscapes in the southern part of Area 12 reflect the different resistance to river
erosion of the Greensand and Chalk bedrock, the features of the northern parts directly
reflect the recent history of river and coastal movement.
FIG
210.
Location map for Area 12.
Landscape A: The Northern Weald
At the beginning of this chapter I introduced the Weald as being exposed within a large
uplift, created by upward movement of the Cretaceous bedrock. In the area around
Maidstone, the northern Weald succession can be seen ranging southwards from Late
Cretaceous Chalk in the North Downs, to the Early Cretaceous Hastings Beds around
Royal Tunbridge Wells.
