Underground streams now can erode weathered limestone, causing the fractures to get larger. Streams continue to connect fractures, creating a network of passages. Speleothems precipitation of CaCO 3 from solution. Stalagmites as water drips from the ceiling, it lands on the floor. Most of the water evaporates, precipitating CaCO 3 .
Evaporites tend to dissolve completely.
Limestone bedrock lies just beneath the surface of of North Central Iowa. Water table will decline, increasing the chance for sinkhole formation.