ABSTRACT

Mössbauer spectroscopy utilizing precise computer-based curve fitting procedures and X-ray diffraction methods have been used to study four deep-sea and one fossil marine manganese nodule. They have shown that X-ray amorphous goethite (α-FeOOH) and probably akaganéite (β-FeOOH) are the secondary iron oxidehydroxide phases present in the deep-sea nodules. The fossil nodule contained goethite with a larger particle size (approx. 350Å) which had presumably been formed by the recrystallization of X-ray amorphous goethite and/or the alteration of the metastable akaganéite.