Molecular hydrogen in minerals as a clue to interpret ∂D variations in the mantle.

ABSTRACT: Trace amounts of water dissolved in minerals affect density, viscosity and melting behaviour of the Earth's mantle and play an important role in global tectonics, magmatism and volatile cycle. Water concentrations and the ratios of hydrogen isotopes in the mantle give insight into these processes, as well as into the origin of terrestrial water. Here we show the presence of molecular H₂ in minerals (omphacites) from eclogites from the Kaapvaal and Siberian cratons. These omphacites contain both high amounts of H₂ (70 to 460 wt. ppm) and OH. Furthermore, their ∂D values increase with dehydration, suggesting a positive H isotope fractionation factor between minerals and H₂-bearing fluid, contrary to what is expected in case of isotopic exchange between minera

SUBMITTER: Moine BN 

PROVIDER: S-EPMC7367874 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature