Five types of mineral resource were known in the sedimentary cover of the oceans and seas floors prior to the 1980's :1)
hydrocarbon fields including some very large zones of oil and gas accumulation; 2) "Red Sea" type thermal oozes with
increased concentrations of noble metals; 3) ferromanganese nodules; 4) concentrations of metallic sulphides ("Black
Smokers"); and 5) cobalt-bearing ferromanganese crusts on the summits and slopes of seamounts. Since then, the so
called "White Smokers", containing sulphides of copper and zinc, have been discovered. The ore horizons (manganese,
copper, nickel and other metals) of the sedimentary cover of deep-sea basins comprise a sixth type of mineral resource in
the oceans. These horizons have not only a theoretical, but also a principal economic significance