Remnants of early Earth differentiation in the deepest mantle-derived lavas

Significance Understanding how the Earth evolved from its accretion to the present-day conditions is a major quest of the Earth sciences. This contribution focuses on the evolution of the deepest realms of our planet sampled by basalts in ocean islands (such as Hawaii) during the last ∼100 to 150 million years and diamond-bearing kimberlites emplaced in continents since ∼2 billion years ago. Radiogenic isotope ratios are employed to demonstrate that these lavas share a common source, which includes a component that originated from melt extraction soon after Earth accretion. These findings help reconcile contrasting geochemical observations in ocean island basalts and provide constraints on the composition and evolution of the deepest and most ancient parts of Earth’s mantle.