Abstract:

The majority of researchers believe that the dominant manganese oxide of Co-rich crusts is vernadite. The data of X-ray diffraction show that pyrochroite is the main mineral oxide phase, which was rarely known in the former studies of manganese nodules and Co-rich crusts. This paper discusses the origin, chemical formula, cell parameter and X-ray powder diffraction data of pyrochroite and vernadite, and suggests that the manganese oxide phase with the values of 2.4×10^-10 m and 1.4×10^-10 m is named as vernadite. The author conjectures that pyrochroite of the Co-rich crusts indicates that the environment of growth of the Co-rich crusts was reducing environment which remained in the later stage.

Key words: Co-rich crusts, pyrochroite, vernadite, Western Pacific