A comprehensive view of manganese nodules and volcanics of the Central Indian Ocean Basin

Abstract

The Central Indian Ocean Basin (CIOB) is the most studied basin in the Indian Ocean because of the Indian Manganese Nodules program. During the last two and half decades (and also on going), immense efforts have been made to investigate the nodule domain so as to locate the first generation nodule mine field. Over 4 million sq. km of the sea floor in the CIOB was surveyed using different samplers and echo sounders (single and multibeam). The basic requirement to identify the mine site was the abundance of the nodules (weight in kg=m sup(2)), grade of the nodule (i.e., combined percentage of Ni + Cu + Co) and the topography of the area. Various aspects related with nodules have been inspected resulting in a number of research publications, and a model derived for the growth and location of mineable ferromanganese deposits in the CIOB. Besides the ferromanganese deposits, this paper also deals with the physiographic features (seamounts, fracture zones), sediment types and on a variety of volcanics and hydrothermal materials recovered from the CIOB. It is inferred that the volcanics constitute an important part of the basin and have influenced the growth of the ferromanganese deposits. It is observed that in the CIOB the presence of seamounts, types of volcanics, episodes of volcanism and altered products vis-a-vis the distribution of ferromanganese deposits are intrinsically woven and complement one another.