Abstract:

More than 200 samples of manganese nodules from the Central Indian Ocean Basin (CIOB) were studied for their different parameters. The study included various aspects such as morphology, texture, mineralogy, and composition of the nodules. The nuclei of the nodules were also examined along with the oxide layers. We attempt to correlate the nucleus (their type and abundance) with the nodule parameters such as their external morphology, chemical composition, and suitable location of formation, amongst others. We found various nucleating materials and these include rock fragments (fresh and altered), clay, pumice and sharks' teeth. In a majority of the cases, rock fragments are dominant in the core of the nodules and these conform to that of the seafloor basalts. The shape of the nuclei influences that of the nodules, especially during their initial period of growth. Irrespective of the kind of nuclei, todorokite is the main mineral of the nodules. The nodules of the CIOB were formed mostly due to hydrogenous accretion of ferromanganese oxides while diagenetic contribution of metals is less common.

Keywords: Central Indian Ocean basin; diagenetic; hydrogenous accretion; manganese nodules; nucleus; todorokite

Document Type: Research article

DOI: 10.1080/10641190802460223

Affiliations: 1: Department of Geological Sciences, Jadavpur University, Kolkata, India 2: National Institute of Oceanography, Dona Paula, Goa, India 3: School of Oceanographic Studies, Jadavpur University, Kolkata, India