Marine geology

Abstract

Significant scientific contributions in Marine Geology in India during the Nineties have been highlighted in this paper. Sediment trap data collected in the Arabian Sea and Bay of Bengal have provided much understanding about annual sediment fluxes, productivity variations and controlling factors for the sinking of fine-grained particles in the ocean. The distribution of lithogenic sediments along the continental margins of India and influence of physical processes on the dispersal of fine-grained sediments has been brought out. Detailed investigations on the ODP cores of the Indian Ocean have provided much refinement in understanding the distribution of various water masses and record of deep sea hiatuses. Investigations on the gas-charged (methane-bearing and gas hydrates) sediments along the Indian continental margins, by using geophysical methods, is a significant achievement in this decade. Authigenic green clay facies, phosphorites have been studied in detail in order to reconstruct the paleogeography of the continental margins. A beginning is made on the hydrothermal deposits of the Andaman Sea. Significant research work was done on various aspects of polymetallic nodules and associated sediments of the Central Indian Basin. Investigations on the Co-rich Fe-Mn crusts from the Afanasy-Nikitin Seamount provided in depth knowledge on the intensity of oxygen minimum zone during late Miocene and also on the evolution of Indian Ocean during Neogene. Rock magnetic techniques have also been employed to understand the late Quaternary paleoclimate of the eastern Arabian Sea