Eclogite resembling metamorphic disequilibrium assemblage formed through fluid-induced metasomatic reactions.

ABSTRACT: Equilibrium omphacite-garnet-bearing mafic rocks have been classified as eclogites, either pristine or retrogressed, that were formed at great depths in the lithosphere. Here we report a unique natural example of eclogite resembling assemblage in disequilibrium formed through fluid-induced metasomatic reactions under the amphibolite to granulite facies. Primarily, the amphibolized protolith experienced a garnet-amphibolite facies metamorphism at ~ 500-700 °C and ~ 0.8-1 GPa. Subsequently, CO₂ fluid induced fracturing and dissolution-reprecipitation reactions occurred at peak metamorphic conditions of ~ 700 °C and ~ 1 GPa. Occasional omphacite-albite assemblage, which gradually replace diopside-oligoclase symplectite adjacent to albite veins along fractures, indicates fluid-induc

SUBMITTER: Kwon S 

PROVIDER: S-EPMC7670418 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature