Platinum and gold in the ferromanganese crusts of the Pacific Ocean

The matter of four technological samples of ferromanganese crusts recovered from IORAN and Dal'morgeologiya guyots (Magellan Seamounts, Pacific Ocean) were studied by a series of physical and chemical methods including analytical electron microscopy. It was found that platinum is predominantly dispersed in the form of native metal; it features no evident relation to ferromanganese phases, though sometimes it is associated with the phosphate phase. In selected cases, the platinum particles may reach 50 to 60 pin in size. The gold is mostly associated with iron minerals; it is strongly dispersed in the form of hydrated species or, rarely, as native metal or as a component of intermetal compounds. The oceanic water is supposed to be the major source for the nannoparticles of precious metals, whereas the larger inclusions of native platinum are related to the underlying weathered basalts.