Petrological and geochemical constraints on the lithology of the Society mantle plume

Intraplate oceanic magmatism is the expression at the Earth’s surface of mantle plumes, generated at various depths in the Earth mantle. Mantle plumes have been active throughout the Earth evolution and take an important part in the Earth differentiation and dynamics, by recycling deep material toward the surface. Ocean island lava chemistry is, therefore, a useful tool to study the deep mantle and to understand the chemical evolution of the Earth.

A major and current challenge is to decipher the lithology of the mantle plume rocks (peridotite vs pyroxenite). We apply a new approach to the ocean island lavas from the Society Archipelago, French Polynesia.

By combining isotope geochemistry and mineral composition, we explore the coupling between chemical composition and lithology of the mantle components in the Society mantle plume. This mantle plume is characteristic of the EM2 mantle end member ; resulting from the recycling into the deep mantle of sediments through subduction processes. Our results will be used to constrain the origin of the EM2 mantle end member and to understand the chemical impact of mantle plume on mantle and crust evolution through time.