The iron oxide mineralogy of sand, silt and clay fractions was studied in five soil materials. Samples were collected from a pedon of a Red Nitossolo (Brazilian Soil Classification; related to an Alfisol in US Soil Taxonomy) developing on a tholeiitic basalt, near the town Tupaciguara (18 o 35 ‘ 33 ” S; 48 o 42 ‘ 18 ” W) in the region of Triângulo Mineiro, state of Minas Gerais, Brazil. Portions of sand and silt were analyzed by magnetic separation and selective chemical treatments with NaOH […]