top of page

Ferromanganese Crusts

Marine ferromanganese crust deposits are hydroxide/oxide deposits of cobalt-rich iron/manganese (ferromanganese) formed by direct precipitation of minerals from seawater onto hard substrates (Fig. 1), and potential mineral resources that contain base metals and strategic and critical elements such as cooper (Cu), cobalt (Co), vanadium (V), niobium (Nb), nickel (Ni), titanium (Ti), tellurium (Te)platinum group elements (PGEs) or rare earth elements (REEs).

Ferromanganese crusts occur at shallower depths of <400 to about > 5000 meters in areas of significant volcanic activity. The crusts grow on hard-rock substrates of volcanic origin by the precipitation of metals dissolved in seawater in areas of seamounts, ridges, plateaus and where prevailing currents prevent deposition of unconsolidated sediments and occupy large areas on top of these topography highs. In many cases, the deposits occur within the exclusive economic zone (EEZ) of the countries.

bottom of page