Major Soil Classes of the Metropolitan Region of Curitiba (PR), Brazil: I - Mineralogical Characterization of the Sand, Silt and Clay Fractions

摘要

The aim of this work was to evaluate the mineralogical and chemical characteristics of most representative soils ofthe Region of Curitiba, Parana State. Samples were collected at different depths. The results showed: (a) the quartzwas the only identified mineral at the silt and sand fractions. The dominant clay mineral was Kaolinite, withcontents ranging from 676.7 to 820.8 g kg~(-1). The gibbsite was also an important constituent of the most weatheredhorizons and the hematite and goethite contents were low, mainly in the Histosol; (b) at the C horizon of theInceptisol, high intensity of vermiculite/smectite reflections were detected (X-ray diffraction), justifying the highcapacity of expansion and contraction, normally showed for this soil horizon; (c) was observed a good relationbetween pedogenetic degree and crystallographic mineral characteristics.