Volcanogenic-hydrothermal iron-rich materials from the southern part of the Central Indian Ocean Basin

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We report the occurrences of magnetite-rich spherules, Ti-rich particles and possibly nontronite recovered at 19°S and 76°E from the pelagic clay in the Central Indian Ocean Basin (CIOB). It is proposed that the magnetite spherules were formed as a result of volcanic activity in this part of the CIOB, while the presence of nontronite suggests localized hydrothermal activity. The magnetic spherules and the associated materials are compared with similar occurrences 555 km to the north in the vicinity of the 76°30'E fracture zone. Considering radiolarian age dating of the sediment, the age of the volcano-hydrothermal episode responsible for the formation of these materials seems to be between 425 and 650 ka. It is inferred that there could have been widespread local volcanism in the CIOB.

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Marine Geology