Environmental Engineering Reference
In-Depth Information
Figure 1
Evolution of a karst landscape. (a) Surface solution
dolines drain water into the limestone, where it develops cave
systems before resurgence along an aquiclude. (b) Continuing
surface solution weathering and cavern collapse progressively
corrode the landscape down to poljes and alluvial plains; residual
towers and cockpits are common in tropical karst.
However, climate change inevitably enters the argument. It is now thought that the
persistence of warm, humid climate throughout the Quaternary in many tropical areas
sustained karst development. Moreover, geological control in climatically similar regions
is evident in contrasting karst development between the massive white limestones (good)
and weak blue limestones (poor) belts of Jamaica. Carboniferous limestone
pavements
and chalk
dry valleys
in northern and southern Britain respectively represent
glaciokarst
landsystems, whose development began during mid to late Pleistocene cold stages (see
Colour Plate 9 between pp. 272 and 273). Their modern form probably reflects recent
exhumation from beneath substantial Holocene soil and vegetation cover by
anthropogenic activities.
