Iron in Soils and Clay Minerals

Book excerpt: The geobiochemical cycle of iron; An introduction to physical and chemical principles; Solubility and redox equilibria of iron compounds in soils; Separation and concentration of iron-containing phases; Phase identification by selective dissolution techniques; The assay for iron in soils and clay minerals; Introduction to crystal structures of iron-containing minerals; The application of micro-beam methods to iron minerals in soils; Some properties of soil and synthetic iron oxides; Occurrence and formation of iron oxides in various pedoenvironments; Properties and behavior of iron oxides as determined by mossbauer spectroscopy; Iron compounds as indicators of pedogenic processes: examples from the southern hemisphere; Magnetic properties of iron in soil iron oxides and clay minerals; Structural iron in kaolinites and in associated ancillary minerals; Role of iron in mica weathering; Structural iron in smectites; The characterization of iron complexes with soil organic matter; Chemistry of iron in calcareous systems; Microbiological reactions of iron in soils; The fate of iron during soil formation in humid-temperate environments; Laterites and laterization processes; Effects of seasonal redox processes involving iron on the chemistry of periodically reduced soils; Long-term chemical, mineralogical, and morphological effects of iron-redox processes in periodically flooded soils; Redox processes of iron and sulfur involved in the formation of acid sulfate soils.