Age Estimates of Inland Dunes in East-Central

Lower Michigan Using Soils Data

Alan F. Arbogast and Thomas P. Jameson

Extensive deposits of eolian sand occur deep (>50 km) within the interior of east-central lower Michigan. These dunes are most common in the Saginaw lowland where they are parabolic, with limbs oriented northwesterly. Their presence on densely forested landscapes indicates that paleoenvironmental conditions differed sufficiently for dune formation to have occurred. In a previous study, Arbogast et al. (1997) illustrated that surface soils in the northwestern part of the Saginaw dune field were morphologically similar, consisting of weakly developed Spodosols (A/E/Bs/C horizonation). Thus, these dunes must have stabilized concurrently following regional mobilization of eolian sand. In this study, we present soils were analyzed at 19 sites in the Deford State Game Area in Tuscola County. Morphologically, the soils within the Deford area are similar (A/E/Bs/C horizonation), indicating that Deford dunes stabilized concurrently. Statistical (ANOVA, KW, factor analysis) comparison of Deford soils and soils to the northwest, however, reveals that significant developmental differences exist between the two areas, with Deford soils being better developed. Given that variables (climate, soil texture, pH) are more conducive for Spodosol development to the northwest, we conclude that Deford soils are older. Thus, Deford dunes must have stabilized prior to their counterparts to the northwest.