Mantle plume chemical diversity

摘要

Mantle plumes are thought to be generated from Earth’s deepest mantle. They well up through the Earth and drive volcanism at the surface, often in the form of lavas erupted at ocean islands. Such plumes therefore provide a precious probe of Earth’s deep mantle, potentially to depths of up to 2,890 km, and are used to infer its chemistry. However, ocean island lavas have complex compositions that cannot be explained by a single source reservoir in the mantle~1. Furthermore, seismic images reveal a strongly heterogeneous deep mantle, supporting the idea of distinct reservoirs with different compositions~2. Writing in Nature Geoscience, Li et al.~3 report the use of numerical simulations of mantle convection to show that plumes generated in the deep Earth can entrain different types of material, including recycled oceanic crust and primordial mantle, and transport it to the surface to generate the heterogeneity observed in ocean island lavas.