Pennsylvanian Clays, clay analysis, Mahaska County, Iowa clays
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.
Proceedings of the Iowa Academy of Science
©1972 Iowa Academy of Science, Inc.
Anderson, Harold Dean
"X-Ray Diffraction Analysis of the Pennsylvanian Clays of Mahaska County,"
Proceedings of the Iowa Academy of Science, 79(3-4), 123-126.
Available at: https://scholarworks.uni.edu/pias/vol79/iss3/9