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).

Figure 1
Figure 1

Cobalt-rich ferromanganese crust recovered on Echo Seamount, Canary Island Seamount Province (Central East Atlantic). Photo: IGME.

Figure 2
Figure 2

Colloform layers of ferromanganese oxy-hydroxides enriched in cobalt and rare earth elements. Photo: IGME.

Figure 1
Figure 1

Cobalt-rich ferromanganese crust recovered on Echo Seamount, Canary Island Seamount Province (Central East Atlantic). Photo: IGME.

1/2

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.

Figure 3
Figure 3

3D bathymetry model of the Echo Seamount (Canary Islands Seamount Province, Central East Atlantic Ocean). Source: Marino et al., 2017 http://dx.doi.org/10.1016/j.oregeorev.2016.10.005.

Figure 4
Figure 4

Co-rich ferromanganese crust recovered in 2011, Drago seamount (Canary Islands Seamounts Province, Central East Atlantic Ocean). Photo: IGME repository.

Figure 5
Figure 5

Ferromanganese crusts covering the seafloor, Tropic Seamount (Canary Islands, Central East Atlantic). Photo: ROV ISIS 6000, NOC.

Figure 3
Figure 3

3D bathymetry model of the Echo Seamount (Canary Islands Seamount Province, Central East Atlantic Ocean). Source: Marino et al., 2017 http://dx.doi.org/10.1016/j.oregeorev.2016.10.005.

1/3