Kansan till outcrops over approximately 25 percent of the surface area in southern Iowa. Most natural outcrops occur along the flanks of loess-capped hills. The texture of the till may be roughly divided into thirds each of clay, silt, and sand and gravel. Quartz and feldspar are the dominant minerals along with montmorillonite and illite-group clay minerals. The majority of the calcareous till classifies as an A-6 engineering material.
Proceedings of the Iowa Academy of Science
©1959 Iowa Academy of Science, Inc.
Dahl, A. R.; Davidson, D.T.; and Roy, C. J.
"Petrography and Engineering Properties Of Kansan Till in Southern Iowa,"
Proceedings of the Iowa Academy of Science, 66(1), 283-301.
Available at: https://scholarworks.uni.edu/pias/vol66/iss1/41