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 calibration^4,5. 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.

The Chang’E-5 (CE5) mission has demonstrated that lunar volcanism was still active until two billion years ago, much younger than the previous isotopically dated lunar basalts. How the small Moon retained enough heat to drive such late volcanism is unknown, particularly as the CE5 mantle source was anhydrous and depleted in heat-producing elements. We conduct fractional crystallization and mantle melting simulations that show that mantle melting point depression by the presence of fusible, easily melted components could trigger young volcanism. Enriched in calcium oxide and titanium dioxide compared to older Apollo magmas, the young CE5 magma was, thus, sourced from the overturn of the late-stage fusible cumulates of the lunar magma ocean. Mantle melting point depression is the first mechanism to account for young volcanism on the Moon that is consistent with the newly returned CE5 basalts.

A natural ilmenite (PZH12-09) is homogeneous and thus suitable for use as a reference material forin situmicroanalysis. An EPMA method was developed to determine the trace elements of ilmenite, with high precision and low detection limits.

To make potassium from K-bearing rocks accessible to agriculture, processing on biotite syenite powder under mild alkaline hydrothermal conditions was carried out, in which two types of KAlSiO4 were obtained successfully. The dissolution-precipitation process of silicate rocks is a significant process in lithospheric evolution. Its effective utilization will be of importance for realizing the comprehensiveness of aluminosilicate minerals in nature. Two kinds of KAlSiO₄ were precipitated in sequence during the dissolution process of biotite syenite. The crystal structures of two kinds of KAlSiO₄ were compared by Rietveld structure refinements. The kinetics model derived from geochemical research was adopted to describe the dissolution behavior. The reaction order and apparent activation energy at the temperature range of 240–300 °C were 2.992 and 97.41 kJ/mol, respectively. The higher dissolution reaction rate of K-feldspar mainly relies on the alkaline solution, which gives rise to higher reaction order. During the dissolution-precipitation process of K-feldspar, two types of KAlSiO4 with different crystal structure were precipitated. This study provides novel green chemical routes for the comprehensive utilization of potassium-rich silicates.

Here, we demonstrate processing techniques for KNO₃ preparation through green chemical reaction engineering of abundant rock-forming minerals to achieve materials sustainability. In this study, chemical reactions at both low and high temperatures were conducted to investigate the extraction of potassium from kalsilite, KAlSiO₄ for use as a K-fertilizer material and simultaneous transformation of kalsilite to materials such as aluminosilicate gel at low temperatures or muscovite at high temperatures; both these materials have many uses. In the low temperature range of 30 to 80 °C, the optimal conditions to extract potassium from KAlSiO₄ and to obtain aluminosilicate gel were found to be as follows: by using the n(HNO₃)/n(KAlSiO₄) ratio of 1.1, solid to water (S/L) ratio of 1 : 10, a reaction time of 3 h and a temperature of 40 °C. In the high temperature range of 210 to 250 °C, both potassium extraction and crystallization of muscovite were achieved at 250 °C. The mechanisms of K extractions and the simultaneous crystallization of muscovite at higher temperatures were determined by using different characterization techniques such as X-ray diffraction, SEM/TEM, Fourier transform infrared spectroscopy (FTIR), and magic-angle-spinning nuclear magnetic resonance spectroscopy (MAS NMR). Results from the above characterization tools demonstrated that kalsilite can be converted to muscovite by dissolution and recrystallization under hydrothermal conditions at 250 °C while releasing K into solution simultaneously. Three comprehensive utilization routes of potassium-rich rocks for KNO₃ preparation were proposed. Our current results suggest that molecular engineering of abundant natural minerals may lead to materials sustainability through a green chemical approach where reactions are conducted in a closed system to prevent pollution and recover all the components as resources.