Geoscience Reference
In-Depth Information
FIG
168.
Slope map showing the main divisions of the bedrock by age. Landscapes
A
to
D
and localities (
c1, c2
etc.) mentioned in the text are also marked.
During and after the formation of this succession of layers there were distinct
episodes of local movement of the Earth, now recorded in the rocks by gentle differ-
ences in the slope or tilt of the layers. The last of the episodes left even the youngest
of the bedrock layers with a gentle southeasterly tilt. This episode appears to be linked
to a general rising of western Britain due to the emplacement of hot, molten rock at
depth, linked to the opening of the Atlantic Ocean. The North Sea was also sinking
at this time, causing a lowering of eastern Britain and adding to the southeasterly tilt.
For Area 9, the important point is that the tilting of the bedrock means that the oldest
and lowest material is exposed in the northwest of the Area (the Carboniferous rocks
of Landscape
A
), while the youngest and highest material is exposed in a very small
patch in the far southeast (the Cretaceous rocks of Landscape
D
).
Landscape A: Carboniferous and earlier bedrock
The northern edge of Area 9 contains the southern ends of two areas distinguished by
bedrock of Carboniferous and earlier age. The presence of Carboniferous material near
the surface here has strongly influenced the ways in which settlement has occurred
in these areas: the presence of coal at depth resulted in the development of the South
Staffordshire and Warwickshire coalfields, which in turn brought widespread industrial
activity to the Birmingham and Coventry areas (Fig. 169).
