Depositional environment of the surface sediments in Central Indian Basin (CIB), Indian Ocean, between 8°–18°S latitude and 72°–79°E longitude, based on their geochemical characteristics

Abstract

To establish the depositional environment of the surface sediments in the Central Indian Basin, Indian Ocean, major and trace element compositions of different sediment types were studied. The study area composed of terrigenous–siliceous transition, calcareous, siliceous, and red clay sediments. The sediment type changed due to various physico‐chemical conditions with varying proportions of biogenic, hydrogenetic, early diagenetic, and detrital inputs. An oxidative environment is present throughout the basin with variable intensity. The terrigenous input was variable in all sediment types, while its signature was traceable up to 15.30°S latitude. The variable distribution pattern of Mnexcess and Feexcess indicate that apart from continental source, there were additional sources of supply for both these elements, with which most of the trace metals like nickel, copper, chromium, vanadium, yttrium, rubidium, and thorium were associated. The Al/Ti ratios of the sediments indicate a terrestrial influence of fluvial nature up to as far as 14°S latitude while, in the calcareous zone, the influence of volcanic precursors was observed. The present study envisages that Alexcess in the sediments adjacent to the ridges and fracture zones might indicate that Al in these areas is not entirely derived from the continental source.