Mineralogy and geochemistry of iron in some recent continental shelf sediments off Goa

Abstract

Fe is present in much higher concentrations in the fine-grained sediments of the inner shelf off the West Coast of India than in the predominantly carbonate sediments of the outer shelf. The results of Mossbauer spectroscopic analyses of these sediments and their < 2 <i>µ</i>m fractions are consistent with X-ray diffraction data and indicate that the Fe is principally associated with clay minerals, particularly montmorillonite. Chlorite and illite are less important sources of Fe in these sediments and Fe oxide hydroxides appear to be present only in small amounts. The inner shelf sediments also contain some pyrite. This indicates a more reducing environment in the inner shelf associated with relatively high detrital sedimentation in this region.