Document Type

Research

Keywords

Karst, Speleology, Caves, Silurian, Hydrology, Iowa caves

Abstract

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.

Publication Date

March 1983

Journal Title

Proceedings of the Iowa Academy of Science

Volume

Issue

First Page

Last Page

Copyright

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File Format

application/pdf

Recommended Citation

Bounk, Michael J. (1983) "Some Factors Influencing Phreatic Cave Development in the Silurian Strata of Iowa," Proceedings of the Iowa Academy of Science, 90(1), 19-25.
Available at: https://scholarworks.uni.edu/pias/vol90/iss1/5

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Some Factors Influencing Phreatic Cave Development in the Silurian Strata of Iowa

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