Oceanic ferromanganese deposits occur mainly in two forms, as nodules and as encrustations; while the nodules form a carpet on the deep-sea abyssal plains, encrustations occur as caps on seamounts. The genesis of nodules has been attributed to multiple processes such as hydrogenetic, diagenetic and mixed, but encrustations are generally believed to be of hydrogenetic origin. It has been estimated that, nearly 43 million km sup(2) of the world's seafloor areas is covered with ferromanganese nodules, totaling to a considerable 1.7 to 3 trillion tons. On the other hand, encrustations have been found on most of the seamounts underlying high productive surface waters. Ferromanganese nodules are known for the enrichment of Copper and Nickel, while encrustations are enriched in cobalt. Their ubiquitous occurrence in almost all the ocean basins make them a potential future multi-metal resource. As encrustation form due to hydrogenetic precipitation of metal hydroxides from the ambient water, they are best suited to trace the contemporary oceanic environment prevalent during their growth period. Several workers have demonstrated that ferromanganese encrustations are the condensed repositories of past-ocean conditions. Exploiting this potential, researchers world over have demonstrated that, Quaternary climatic fluctuations, deep-water circulation changes, major erosional episodes and similar events have left behind unambiguous records in the encrustations. Thus the oceanic ferromanganese deposits not only are important as potential resources, but because they also host valuable records of paleocean environment