| Abstract Submission No. | ABS-2.1-0206 |
| Title of Abstract | Evidence for Multi-Source Hydrothermal Venting at 67.67°E, eastern SWIR |
| Authors | Sai Pavan Kumar Pillutla* |
| Organisation | National Centre for Polar and Ocean Research |
| Address | NCPOR, Headland Sada Vasco-da-Gama, Goa, India Pincode: 403804 E-mail: saipavan@ncpor.res.in |
| Country | India |
| Presentation | Poster |
| Abstract | Water column studies conducted along the eastern Southwest Indian Ridge (eSWIR) during scientific cruises MGS26 and MGS36 have identified several hydrothermal plumes. Anomalies in turbidity and temperature across various depths (three) confirm the presence of a hydrothermal field near 67.67°E, 26.61°S. Chemical tracer analyses of these three plumes revealed dissolved methane (CH₄: 1.0¿37.8 nmol/kg) and dissolved manganese (DMn: 1.0¿68.6 nmol/kg) concentrations. Detailed physico- chemical characterization indicates that Plume Layer 1 represents a transient (event-type) plume, while Layers 2 and 3 are chronic in nature. Plume Layer 2, spanning depths of 3400 to 4100 m, comprises two distinct fields¿two located south of the axial high and one independent field to the north. Plume Layer 3 originates at depth around 4200m is from a separate hydrothermal source. Despite the differing origins, the geochemical CH₄/DMn ratios predominantly fall below 0.5, with a few approaching 1. These values suggest seawater interaction with mafic rocks and are consistent with hydrothermal systems typical of mid-ocean ridges. |
| Keywords | Hydrothermal plumes, methane, manganese |