"How karst forms"
How karst forms. Karst 2-1 Some rocks, such as limestone, can be dissolved by weakly acidic water. Karst 2-2 Carbon dioxide in air and soil combines with water to form weak carbonic acid. Karst 2-3 Water containing carbonic acid can slowly dissolve limestone, especially along fractures. Karst 2-4 As fractures enlarge, they can become caves. Karst 2-5 Caves can be very large underground. Karst 2-6 Collapse of cave roofs causes sinkholes. Karst 2-7 Natural filling of sinkholes sevelops gently rolling sinkhole plains. Karst 2-8 Dissolving large amounts of limestone leaves behind remnant rock towers. Karst 2-9