Mineralogy of Two Sandy Spodosol Hydrosequences in Michigan

This study was conducted to determine the effect of natural drainage on sand‐, silt‐, and clay‐size minerals in two sandy hydrosequences of Spodosols in northern Michigan. Depth to water tables were monitored using piezometers. Minerals in the dominant sand fraction were identified and quantified using a petrographic microscope. Minerals in the silt and clay fractions were identified and semiquantified using x‐ray diffraction. Sand mineralogy was dominated by quartz with small amounts of feldspars and sericite (altered muscovite). Silt fractions were composed of quartz with lesser amounts of feldspars. Weathering of minerals in the sand and silt fractions appeared to be hindered by high water tables, especially in the poorly drained soils. Clay mineral distribution in the hydrosequences suggests that muscovite has transformed to vermiculite in B horizons and through vermiculite to smectite in E horizons. Weathering intensity of this sequence was apparently impeded by water saturation in these two hydrosequences. Most trioctahedral chlorite appeared to have completely dissolved or decomposed to soluble products in E and B horizons.