Peridotites and related gabbroic rocks are widely exposed in the Central Indian Ridge, where the H2-rich-fluid-bearing Kairei hydrothermal field exists. We report on petrological and mineralogical characteristics of peridotites and gabbroic rocks recovered from an oceanic core complex at a latitude of 25° South (25°S OCC) and the Yokoniwa Rise around the Kairei hydrothermal field. Gabbros recovered from the 25°S OCC show a wide range of variations in terms of mineral chemistry and mineral assemblages (olivine-gabbro, gabbronorite to highly evolved oxide gabbro) and are similar to those from the Atlantis Bank of the Southwest Indian Ridge, an ultraslow-spreading ocean ridge. Peridotites recovered from 25°S OCC and the Yokoniwa Rise are generally characterized by moderately to highly depleted melt components. The partial melting of these peridotites is followed by chemical modification through interaction with a wide range of melts from relatively less evolved to highly evolved characteristics. Moderately to highly depleted melt components in the studied peridotites can be explained as being either residue after a relatively high-melt productivity period in intermediate-spreading ridges or a geochemically distinctive domain which has suffered from partial melting in the past rather than partial melting beneath the present mid-ocean ridge systems.
CITATION STYLE
Morishita, T., Nakamura, K., Shibuya, T., Kumagai, H., Sato, T., Okino, K., … Takamaru, R. (2015). Petrology of peridotites and related gabbroic rocks rround the kairei hydrothermal field in the central Indian ridge. In Subseafloor Biosphere Linked to Hydrothermal Systems: TAIGA Concept (pp. 177–193). Springer Japan. https://doi.org/10.1007/978-4-431-54865-2_14
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