AN EXAMINATION OF PODZOLIZATION NEAR LAKE-MICHIGAN USING CHRONOFUNCTIONS

A chronosequence of sandy soils was investigated on four terraces near Lake Michigan to assess rates of podzolization and changes in soil properties with age. The terraces ranged in age from 3000 to 10 000 BP. Each surface was systematically sampled to determine the modal profile, which was then described and sampled. Quantities of OC, Fe, and Al in the B horizons of modal soils increased with soil age. Silt content of surface horizons also increased with age, possibly due to eolian input or physical weathering. For weighted profile and B horizon Al and Fe averages and a variety of soil development indices, a single logarithmic model generally gave the highest statistical significance of the three chronofunction models used. All pedons sampled failed to classify as Podzols, but the oldest two met the criteria for the Spodosol order. Thus, more than 4000, but less than 10 000, years are required for the development of a spodic horizon in Michigan.