Geology Reference
In-Depth Information
In summary, the Barn Mountains landscape contains a different suite of landforms
to that of the Beaufort Plain. To a large extent, the difference refl ects geology. Certain
elements resemble those of hot, semi-arid regions.
2.4. RELICT PERIGLACIAL LANDSCAPES
While certain lithologies may be highly susceptible to frost action and to distinct land-
scape modifi cation, it is equally true that other lithologies are better suited to the preser-
vation of periglacial features long after the disappearance of periglacial conditions. These
ideas are explored in this section, where two lowland landscapes from the never-glaciated
and now-temperate mid-latitudes are described. Both may be viewed, to varying degrees,
as relict periglacial landscapes.
2.4.1. Chalk Uplands, Southern England and Northern France
The chalklands of Southern England and Northern France (
latitudes 48-52° N) are
underlain by thick sequences of relatively pure, soft calcareous sedimentary rock of
Cretaceous age. It is highly porous and permeable. The Chalk forms broad plateaus, strik-
ing in-facing escarpments, and gentle dip-slope surfaces. The extent of the Chalk outcrop
along the English Channel coastlands is illustrated in Figure 2.7.
∼
4
London
1
3
2
Paris
FRANCE
Figure
2.7.
Map showing extent of the Chalk outcrops in southern England and northern France.
Legend: 1-Isle of Thanet (see Figure 13.2); 2-Pays de Caux (see Figure 13.5B); 3-Clatford Bottom
(see Figure 13.10); 4-Walton Common (see Figure 12.6).
