Abstract
The sea floor of the Indian Ocean and the continental margins bordering the ocean are covered by a wide variety of terrigenous, biogenous and anthigenic mineral deposits. The biogenous deposits in the Indian Ocean comprise the corals on shallow banks and on the continental shelves and the oozes in the deep sea. The anthigenic deposits in the Indian Ocean comprise the phosphorites and the polymetallic nodules. Occurrences of phosphorite deposits have been found both along continental margins (South Africa and Western India) and around seamounts (Eastern and Western Indian Ocean). The polymetallic nodules in the Indian Ocean cover an area of 10-15 .10 super(6) km super(2) and the resources are estimated to be about 1.5 .10 super(11) tonnes. A study of over 900 chemical analyses from 350 stations shows that the deposits in most of the basins are submarginal; in the Central Indian Ocean they are paramarginal (Ni + Cu + Co > 2.47% and concentrations > 5kg.m super(-2)).