Page 203 - Fundamentals of Geomorphology

186 PROCESS AND FORM

Table 8.1 Karst and pseudokarst
Formed in Formative processes Examples

Karst
Limestone, dolomite, and other Bicarbonate solution Poole’s Cavern, Buxton, England;
carbonate rocks Mammoth Cave, USA
Evaporites (gypsum, halite, Dissolution Mearat Malham, Mt Sedom, Israel
anhydrite)
Silicate rocks (e.g. sandstone, Silicate solution Kukenan Tepui, Venezuela; Phu Hin Rong
quartzites, basalt, granite, Kla National Park, Thailand; Mawenge
laterite) Mwena, Zimbabwe
Pseudokarst
Basalts Evacuation of molten rock Kazumura Cave, Hawaii
Ice Evacuation of meltwater Glacier caves, e.g. Paradise Ice Caves,
USA
Soil, especially duplex profiles Dissolution and granular Soil pipes, e.g. Yulirenji Cave,
disintegration Arnhemland, Australia
Most rocks, especially bedded Hydraulic plucking, some Sea caves, e.g. Fingal’s Cave, Isle of
and foliated ones exsudation (weathering by Staffa, Scotland
expansion on gypsum and
halite crystallization)
Most rocks Tectonic movements Fault fissures, e.g. Dan y Ogof, Wales;
Onesquethaw Cave, USA
Sandstones Granular disintegration and Rock shelters, e.g. Ubiri Rock, Kakadu,
wind transport Australia
Many rocks, especially with Granular disintegration Tafoni, rock shelters, and boulder caves,
granular lithologies aided by seepage moisture e.g. Greenhorn Caves, USA

Source: Partly after Gillieson (1996, 2)

in karst landscapes, but it may be subordinate to other is irregular terrain produced by the thawing of ground
geomorphic processes. Various terms are added to karst ice in periglacial environments and is not strictly karst
to signify the chief formative processes in particular or pseudokarst at all, but its topography is superficially
areas. True karst denotes karst in which solutional pro- similar to karst topography (see p. 284).
cesses dominate. The term holokarst is sometimes used Karst drainage systems are a key to understanding
to signify areas, such as parts of southern China and many karst features (Figure 8.4). From a hydrological
Indonesia, where karst processes create almost all land- standpoint, karst is divided into the surface and near-
forms. Fluviokarst is karst in which solution and stream surface zones, or epikarst, and the subsurface zones,
action operate together on at least equal terms, and is or endokarst. Epikarst comprises the surface and soil
common in Western and Central Europe and in the mid- (cutaneous zone), and the regolith and enlarged fissures
western United States, where the dissection of limestone (subcutaneous zone). Endokarst is similarly divided into
blocks by rivers favours the formation of caves and true two parts: the vadose zone of unsaturated water flow and
karst in interfluves. Glaciokarst is karst in which glacial the phreatic zone of saturated water flow. In the upper
and karst processes work in tandem, and is common in portion of the vadose zone, threads of water in the sub-
ice-scoured surfaces in Canada, and in the calcareous cutaneous zone combine to form percolation streams,
High Alps and Pyrenees of Europe. Finally, thermokarst and this region is often called the percolation zone.