The nature of the lithospheric mantle is largely constrained from the petrological and geochemical studies of xenoliths. Mantle xenoliths from cratonic regions are distinctly different from those occurring in younger non-cratonic areas. Basalts and other mantle-derived magmas provide us another opportunity to study the chemical and physical properties of this mantle reservoir. Percolation of melts and fluids through the lithospheric mantle significantly modified the petrological features of this reservoir, which can best be recorded in mantle xenoliths brought to the surface by oceanic and continental volcanism. In addition, the petrological and geochemical study of orogenic peridotites is the optimal supplement to mantle xenoliths providing additional field relationships that are totally lacking in the mantle xenoliths.
The Earth’s mantle and crust have been continuously co-evolving since the earliest stages of Earth’s history. This complex differentiation history has given rise to geochemically enriched and depleted domains that may exist at all scales within the silicate portion of the Earth. Domains of distinct age and composition possess measurable differences in their geochemical, petrological and geophysical characteristics. Evidence of heterogeneity may be brought to the surface by a variety of samples of different ages, and studying this heterogeneity is essential to understanding a wide variety of processes that have and continue to control the evolution of our planet.

This session’s research focus lies on mineralogical, petrological and geochemical studies of mantle xenoliths, orogenic peridotites and mantle derived rocks deciphering melting, metasomatic processes and the nature of the metasomatic agents operating in the lithospheric mantle, as well as the formation and preservation of heterogeneous mantle domains, using isotopic, geochemical, geophysical and experimental studies.

Invited speaker: Catherine Chauvel (IPGP)