Society mantle plume, French Polynesia

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 – Sr-Nd isotope composition of ocean island lavas. The composition of the mantle end members is reported.
b – Location and age of the studied islands in the Society Archipelago.

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.

Collaborations
ISTerre: C. Chauvel, A. Sobolev

Fundings
2012: SMINGUE (23k€)

Publications
Cordier, C., Chauvel, C. and Hémond, C. (2016) High-precision lead isotopes and stripy plumes: Revisiting the Society chain in French Polynesia. Geochim. Cosmochim. Acta 189, 236-250. link

Conferences
Cordier C., Chauvel C., Hémond C. (2016) Linking Isotope Variations in OIB and Deep Mantle Structure: the Counter-Example of Society Islands, French Polynesia. American Geophysical Union General Assembly, 19.
Cordier C., Chauvel C., Hémond C. (2016) Stripy mantle plumes: the nonexample of Society Islands, French Polynesia. Réunion des Sciences de la Terre. #115554.
Chauvel C., Delavault H., Cordier C. (2014) Polynesia: a weak and disorganized superplume. Goldschmidt Conference, 388.
Cordier C., Chauvel C., Guillet M. (2013) Mafic lavas constrain the chemical variability of the Society plume. Mineralogical Magazine, Goldschmidt Conference Abstracts, 77, #916.