Manganese oxide accumulations associated with some soil structural pores. I. morphology, composition and genesis

The morphology and composition of manganese oxide accumulations associated with the structural pores in a black earth (Typic Pellustert) subsoil layer were examined using light microscopy, electron microscopy, X-ray diffraction and electron micro-analytical techniques. Birnessite was identified as the crystalline manganese oxide phase. There were significant positive correlations between cobalt, calcium and manganese and a significant negative correlation between iron and manganese. It was most probable that both microbial oxidation and auto-oxidation of Mn2+ contributed to the formation of the manganese oxide accumulations in this soil.