Arc magmas oxidised by water dissociation and hydrogen incorporation in orthopyroxene.

ABSTRACT: Elevated H₂O concentrations and oxygen fugacities are two fundamental properties that distinguish magmas formed in subduction zones from new crust generated at mid ocean ridges. However, the mechanism of magma oxidation, and how it relates to the increase in H₂O remains unclear. In this study, we use infrared spectroscopy of mantle wedge orthopyroxene to trace the temporal and spatial evolution of oxygen fugacity during transport of hydrous arc melts towards the crust. A positive correlation between equilibrium oxygen fugacity and orthopyroxene H₂O concentrations for the peridotite samples studied allowed the assignment of specific, commonly-observed absorption bands to redox-sensitive crystallographic defects. H₂O content associated with these r

SUBMITTER: Tollan P 

PROVIDER: S-EPMC6675610 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature