Barium in ferromanganese crusts from the Sea of Japan: peculiarities of allocation and interrelation with main ore phases

Ferromanganese crusts of the Sea of Japan are characterized by a high content of manganese (up to 63 %) and barium (up to 3 %). A detailed analysis of 64 FMC samples taken on 19 submarine volcanic elevations showed that barium was found in them both as barite, and was a part of the manganese matrix, enriching it in some areas up to 6.5 %. Barite in the form of fine grains was present in the manganese matrix of almost all studied samples, sometimes filling cracks in it completely or partially. There were dendritic crystals of barite, forming spotted precipitates on iron-siliceous or in manganese-iron-siliceous matrices. Features of the allocation of barite suggest that the process of barite formation is superimposed and occurs in the last stage of the formation of FMC.