Qualitative and quantitative determination of the iron-bearing phases in deep sea-nodules by Mössbauer spectroscopy

The iron-bearing phases in nodules from two regions (the Pacific Ocean — Clarion-Clipperton, and the Indian Ocean — Central plain) have been studied by Mössbauer Spectroscopy. The major compounds are established to be Fe(OH)₃, (FeOOH·H₂O) and FeCO₃. The value of the recoilless absorption probability f′ is measured for Fe(OH)₃. Meisel's method for quantitative determination of iron containing compounds has been adapted for the case of nodule samples. By taking into account the f′ values, the error of quantitative determination is considerably reduced. The Fe²⁺ distribution in the nonequivalent M1 and M2 positions of pyroxene has been studied. It is shown that the pyroxene crystals in the silicate material originated as a result of rapid cooling of the magma in ocean water.