REORGANIZATION OF SOIL MATERIALS IN THE GENESIS OF AN ACID LUVISOLIC SOIL OF THE PEACE RIVER REGION, ALBERTA

Abstract

The Boundary soil is described as a "podzolic complex" developed from acidic parent material derived from shale of Cretaceous age. The soil has low pH and base saturation values that result from the formation of sulfates, primarily natrojarosite, and its subsequent alteration in the soil solum to various forms of hydrated iron oxides. The iron oxides impart to the B horizon reddish hues of high chroma. The acidic condition has resulted in weathering of clay-sized mica to vermiculite, especially in the upper part of the solum. Results from micromorphological and analytical studies also show that considerable clay and, to a much lesser extent, organically combined iron and aluminum have been leached from the upper solum and deposited throughout the lower solum and C horizon. Reorganization of clay through illuviation appears to extend well into the C horizon. Microscopic investigations show strong reorganization of materials in the upper solum to a granic–granoidic fabric by biological processes and in the middle solum to granoidic and metafragmic fabrics, probably through coalescence of granic units by freeze–thaw processes.