The Moon has a magmatic and thermal history that is distinct from that of the terrestrial planets1. Radioisotope dating of lunar samples suggests that most lunar basaltic magmatism ceased by around 2.9–2.8 billion years ago (Ga)2,3, although younger basalts between 3 Ga and 1 Ga have been suggested by crater-counting chronology, which has large uncertainties owing to the lack of returned samples for calibration4,5. Here we report a precise lead–lead age of 2,030 ± 4 million years ago for basalt clasts returned by the Chang’e-5 mission, and a 238U/204Pb ratio (µ value)6 of about 680 for a source that evolved through two stages of differentiation. This is the youngest crystallization age reported so far for lunar basalts by radiometric dating, extending the duration of lunar volcanism by approximately 800–900 million years. The µ value of the Chang’e-5 basalt mantle source is within the range of low-titanium and high-titanium basalts from Apollo sites (µ value of about 300–1,000), but notably lower than those of potassium, rare-earth elements and phosphorus (KREEP) and high-aluminium basalts7 (µ value of about 2,600–3,700), indicating that the Chang’e-5 basalts were produced by melting of a KREEP-poor source. This age provides a pivotal calibration point for crater-counting chronology in the inner Solar System and provides insight on the volcanic and thermal history of the Moon.
Unravelling the volcanic history of the enigmatic lunar farside is essential for understanding the hemispheric dichotomy of the Moon1–3. Cratering chronology established for the lunar nearside has been used to suggest long-lived volcanism on the farside of the Moon3,4 but without sample verification. We describe two episodes of basaltic volcanism identified by Pb–Pb dating of basalt fragments returned by the Chang’e-6 mission. One high-Al basalt fragment, dated at 4,203 ± 4 million years ago (Ma), has a source 238U/204Pb ratio (µ value) of approximately 1,620, implying a KREEP-rich (K, rare earth elements and P) source for this oldest-known example of basaltic volcanism among returned samples. The main volcanic episode of the Chang’e-6 basalt documents a surprisingly young eruption age of 2,807 ± 3 Ma, which has not been observed on the nearside of the Moon. The initial Pb isotope compositions of these younger basalts indicate a derivation from a source with a µ value of approximately 360, indicating a KREEP-poor mantle source. Mare volcanism on the lunar farside thus persisted for over 1.4 billion years, even if the source was depleted in heat-producing elements. The consistency between the 2.8-billion-year basalt age and the crater-counting age indicates that the cratering chronology model established for the lunar nearside is also applicable to the farside of the Moon.
There is extensive geologic evidence of ancient volcanic activity on the Moon, but it is unclear how long that volcanism persisted. Magma fountains produce volcanic glasses, which have previously been found in samples of the Moon’s surface. We investigated ~3000 glass beads in lunar soil samples collected by the Chang’e-5 mission and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes. Uranium-lead dating of the three volcanic glass beads shows that they formed 123 ± 15 million years ago. We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma.