Modes of occurrence of noble and nonferrous metals in ferromanganese formations in the central part of the Sea of Okhotsk

A study investigated ferromanganese crusts from the Kashevarov Bank, Deryugin Basin, and Akademiya Nauk Rise in the central part of the Sea of Okhotsk. Judging from the structure of the crust on the Kashevarov Bank, metals in this area could initially be accumulated in the primary sediment that was later cemented by the ferromanganese hydroxides. However, we cannot conrm this statement, because the crust was formed in several stages. This is suggested by the abundance of manganese hydroxide veinlets in the ferruginoussiliceous zones.