A sample of the Moon’s far side retrieved by Chang’e-6 contains 2.83-billion-year-old basalt

Abstract

Remote sensing observations have shown that the far side of the Moon (lunar farside) has different geology and rock composition to the near side, including the abundances of potassium, rare earth elements, and phosphorus (collectively known as KREEP). The Chang’e-6 (CE-6) spacecraft collected samples from the South Pole-Aitken (SPA) basin on the farside and brought them to Earth. We use lead-lead and rubidium-strontium isotope systems to date low-titanium basalt in a CE-6 sample, finding a consistent age of 2830 ± 5 million years. We interpret this as the date of volcanism in SPA and incorporate it into lunar crater chronology. Strontium, neodymium and lead isotopes indicate the volcanic magma was from a lunar mantle source depleted in incompatible elements and containing almost no KREEP component.