Application of Mössbauer Spectroscopy to Determine the Redox Potential of the Upper Mantle

The chemical composition of mineral associations in the rock of mantle xenoliths was investigated, the content of Fe2+ and Fe3+ being determined by the Mossbauer spectroscopy technique. The crystallization conditions (temperature, pressure, and oxygen fugacity) of mantle xenoliths and the composition of the coexisting mantle fluids were assessed. The dependence of the iron oxidation state in spinels on the fugacity of oxygen in a particular system was determined.