Karst, Speleology, Caves, Silurian, Hydrology, Iowa caves
The Silurian strata of eastern Iowa are characterized by solutional karst, expressed in part as caves. Most of the caves were developed within the phreacic zone although they generally are now hydrologically inactive. The formation of this karst was controlled by numerous factors. These include stratigraphically controlled variations in prekarst porosity, hydraulic conductivity, and clay content which affects solubility. These key factors are seen in both the Cyclocrinites Beds of the Hopkinton Dolomite and a portion of the Gower Fm., both of which contain a disproportionate number of caves. In many shallow phreatic caves within the Silurian rocks passage morphology is controlled by the relationship between jointing and the hydraulic gradient. The alignment of these caves parallel to present-day ground-water flow lines indicates that they were probably developed after the present-day stream systems were in place. Therefore, the caves probably formed somewhere between the last glaciation in northeast Iowa (Pre-Illinoian) and the draining of the cave bearing strata.
Proceedings of the Iowa Academy of Science
© Copyright 1983 by the Iowa Academy of Science, Inc.
Bounk, Michael J.
"Some Factors Influencing Phreatic Cave Development in the Silurian Strata of Iowa,"
Proceedings of the Iowa Academy of Science: Vol. 90:
, Article 5.
Available at: http://scholarworks.uni.edu/pias/vol90/iss1/5