Micromorphology and submicroscopy of illuviated mineral particles in boreal clay soils of Saskatchewan, Canada

Abstract

Fine-textured soils developed on glaciolacustrine sediments in the humid Boreal Forest ecoregion of Saskatchewan were studied using micromorphological and submicroscopic techniques to understand the mechanism of illuviation and to overcome the uncertainties in horizon designation. The most striking micromorphological features in the solum were illuviation cutans with mostly striated orientation. Scanning electron microscopic observations showed ripple-mark patterns of translocated silt- and coarse-clay-sized particles on ped surfaces and their wavy lamination in a transverse section. It is hypothesized that a rather permanent system of narrow cracks in the upper solum of these clay soils facilitates rapid translocation of mineral particles. Such a non-selective illuviation is believed responsible for lack of distinct morphological difference between eluvial and illuvial horizons. Horizon designation was complicated by the presence of illuviation cutans in horizons that otherwise had unaltered parent material (unistrial fabric). A solution to this problem is attempted.