Hydrothermal Activity Along Multiple Ridge Segments of the Northern Central Indian Ridge, 8°-17°S

Abstract

We report the first systematic hydrothermal plume surveys conducted on the northern Central Indian Ridge (CIR, 8-17°S), a slow spreading ridge with rates between ~35 and 40 mm/yr during the CIR research program of KORDI between 2009 and 2011. Evidence for hydrothermal activity was found on each of the seven segments, with most plumes found between 3,000 and 3,500 m. Using only on-axis CTD stations within the axial rift valley, the estimated value of plume incidence (ph=0.218) coincides with the global trend between the spatial density of hydrothermal plumes and full-spreading rate (an indicator of magmatic budget). However, there are also indications of possible discharge from hydrothermal activity or serpentinization from the axial walls or ridge flanks (existent ocean core complexes), as has been observed along the Mid-Atlantic Ridge. Our preliminary results support the increasing role of tectonic control on hydrothermal activity as spreading rates decrease.d 2011. Evidence for hydrothermal activity was found on each of the seven segments, with most plumes found between 3,000 and 3,500 m. Using only on-axis CTD stations within the axial rift valley, the estimated value of plume incidence (ph=0.218) coincides with the global trend between the spatial density of hydrothermal plumes and full-spreading rate (an indicator of magmatic budget). However, there are also indications of possible discharge from hydrothermal activity or serpentinization from the axial walls or ridge flanks (existent ocean core complexes), as has been observed along the Mid-Atlantic Ridge. Our preliminary results support the increasing role of tectonic control on hydrothermal activity as spreading rates decrease.