Micromorphological and Mineralogical Properties of Carbonates in Some Aridisols and Inceptisols

Carbonates are among the most common soil constituents in arid and semiarid zones. They exhibit many significant differences in their chemical and mineralogical, suite, origin, physical and micromorphological properties and consequently in their activities in soil. The differences cause different properties of calcareous soils. Six profiles of Aridisols and Inceptisols with carbonate accumulations were selected and analyzed as according to standard methods. Following an analysis of the physical and chemical properties, thin sections were prepared and scrutinized for a distinction of the origin of carbonates, using staining with Figel and red Alizarin red solutions. Powder X ray diffractometry was carried out for carbonate detection, while clay mineralogy study being done on the oriented pure clay samples. Micromorphology and mineralogy of carbonates (nodules, sparite, micrite, needle-shape calcite and laminarcap) showed calcium carbonate as the dominant carbonatic mineral. However calcium/magnesium carbonates were also recognized as present in some cases. The dominant clay minerals were spotted as smectites.