“…The mineralogy of areas north of our study sites showed high amounts of kaolinite (Parham, 1976), which we assume were transported and deposited during the last glaciation. Similar studies have shown considerable amount of kaolinite found in the surface and subsurface horizons of soils in the Iowa Erosion Surface (Wysocki, 1983;Effland, 1990). Moreover, loess from northeast Iowa along the Mississippi river were dominated by kaolinite and illite (Ruhe, 1984;Williams et al, 2010).…”