KARSTold

KARST landscapes consist of limestone areas that have been sculpted by a combination of erosion and chemical dissolution to form dramatic topographies such as that typified by the Cockpit Country.

Much of the pioneering work in karst began in Yugoslavia. In fact, the term "karst" comes from the Slav word, "krs," and is associated with the limestone country in western Slovenia. Other terminology, such as doline, uvala, and polje, also originated here (Jennings, 1971).

On Jamaica, the karstification of the White and Yellow Limestone Groups, which vary considerably in quality (e.g., purity, hardness) and depth, has resulted in a landscape varying from gently rolling, soil-covered plains through rough and jumbled deep depressions, isolated towers, and pointed hills. (White 1988). Cockpit karst is a special form of "Conekarst" in which the residual hills are chiefly hemispheroidal and surround closed, lobed, depressions known as dolines or "cockpits" each of which is drained to the aquifer by one or more sinkholes. The dolines have concave floors covered with a variable amount of rock rubble and soil, which, in Jamaica, has often been redistributed to form a flat floor as a result of repeated floodings. The hilltops and slopes are marked by a distinctively minimal clay soil and organic humus while the talus have retained soil coverage. Cockpits average in depth from 100 - 120m and walls generally slope from 30 - 40deg. Drainage of the cockpit bottoms occurs via percolation or by sinkhole. Drainage by the latter creates a complex, subterranean cellular network. The periphery of Cockpit Country is marked by 'degraded' cockpits, glades and valleys (poljes), such as seen in the Windsor, Pantrepant, and Fontabelle areas, terminating to the west in the Queen of Spain's Valley, the best known and largest polje in Jamaica. "Tower" karst (steep, near vertical sides) is found to the north in the Duanvale Fault zone as well as in the southeast region.

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