Marine mineral resources of the Central Indian Basin: Ferromanganese nodules and crusts

Abstract

The morphology, mineralogy and composition of ferromanganese nodules and crusts from the Central Indian Basin and southwestern flank of the Charlsberg Ridge have been characterized from the analyses of data and samples collected at more than 2000 locations. Two different depositional processes, namely diagenetic and hydrogenous, through which nodules and crusts grow, are responsible for morphological and compositional variations. Rough surface nodules from the siliceous sediments have todorokite as the dominant mineral and contain higher concentrations of Mn, Ni and Cu due to the supply of these metals during early diagenesis. Smooth surface nodules associated with pelagic clays have Delta - MnO