EARTHSC 2GG3 Lecture Notes - Lecture 8: Karst, Sinkhole, Flowstone
17 Dec 2019
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Document Summary
Subsidence is a slow or rapid, nearly vertical, downward movement of earth"s surface: karst: landscape resulting from the dissolution of limestone, dolostone, marble, gypsum or rock salt. Soil expansion and contraction results from: changes in the water content of soil. Subsidence is not usually life threatening, but is one of the most widespread and costly natural hazards. Common type of landscape associated with subsidence: rocks are dissolved by surface water or groundwater, dissolution produces voids which join to form caves and sinkholes, a surface pockmarked with a large number of sinkholes is a karst plain. Can range from one to several hundred metres in diameter. Two basic types: solution sinkholes: pits formed by dissolution of buried bedrock along planes and fractures, collapse sinkholes: collapse of surface or near-surface rock or sediment, when the water table falls, thats when collapsing begins.
