Clay Mineral Alteration in Some Indiana Soils

Abstract
X-ray analyses of samples from thirteen soil profiles that were formed on glacial till, loess, and Mississippian limestones of Indiana indicate that (1) in some soil profiles chlorite of the parent material is changed completely to montmorillonite with intermediate stages of random mixed layers of chlorite-vermiculite-montmorillonite; (2) some of the illite of the parent material produces montmorillonite through random mixed layering of illite-montmorillonite, but the illite is not entirely altered in any profile; and (3) kaolinite may be produced as a weathering product, or it may remain unchanged from the parent material.