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Document Type

Research

Keywords

Pennsylvanian Clays, clay analysis, Mahaska County, Iowa clays

Abstract

This study involved five of the operating open-pit mines of Mahaska County, Iowa, which are located near the eastern edge of the Mid-Continent Basin. The mines were sampled from the underclay to the surface at two foot intervals and the clay fraction was separated and analyzed both qualitatively and quantitatively. Results of this investigation showed that the major component present besides illite and kaolinite in the hulk sample was quartz. However, the quartz was not present in the less-than-two micron fraction. The clay fraction analysis varied from 38 percent to 60 percent kaolin and 17 percent to 26 percent illite with the remainder being chlorite and non-swelling mixed-layered material; chlorite was present in only eleven of the samples collected. The mineralogy was used as evidence that these rocks were deposited in near shore environment. This interpretation when considered along with stratigraphic work of others suggests that the rocks are in the Cherokee Group.

Publication Date

December 1972

Journal Title

Proceedings of the Iowa Academy of Science

Volume

79

Issue

3-4

First Page

123

Last Page

126

Copyright

© Copyright 1972 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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