The tungsten-182 record of kimberlites above the African superplume: Exploring links to the core-mantle boundary

摘要

Many volcanic hotspots are connected via 'plume' conduits to thermochemical structures with anomalously low seismic velocities at the core-mantle boundary. Basaltic lavas from some of these hotspots show anomalous daughter isotope abundances for the short-lived I-129-Xe-129, Sm-146-Nd-142, and Hf-182-W-182 radioactive decay systems, suggesting that their lower mantle sources contain material that dates back to Earth-forming events during the first 100 million years in solar system history. Survival of such 'primordial' remnants in Earth's mantle places important constraints on the evolution and inner workings of terrestrial planets.