The PIs will investigate the blueschist samples collected during earlier cruises from the Mariana Forearc. The Mariana is the only area where direct samples are available from deep-seated material brought to the seafloor by mud volcanoes with deep faults acting as conduits for this deep forearc material. Isotopic studies of the pore fluids, enclosing solid material and fluid/gas inclusions will reflect the source regions and enroute water-rock interactions. The study will provide better constraints on temperature-pressure conditions of the deep forearc mantle wedge near the decollement and nature of the water-rock interactions in convergent margins.
