Micro-scale (1 μm) Mg isotope analysis of olivine by NanoSIMS with online matrix correction and its application to Chang'e-5 sample.

In-situ stable Mg isotope analysis of olivine, the most common mineral in igneous and metamorphic rocks, provides critical insights into their formation and timescales. However, accurate correction of significant matrix effects is hampered by the lack of olivine reference materials with forsterite (Fo) content below 80. More importantly, current techniques using secondary ion mass spectrometry (SIMS) or laser ablation-multi collector-ICP-MS (LA-MC-ICP-MS) are insufficient to decipher geological processes occurring at fine scales (<10 μm).

First classification of iron meteorite fragment preserved in Chang'e-5 lunar soils.

Lunar soil preserves numerous fragments of meteorites impacting on the Moon, providing a unique opportunity to investigate the distribution of the types of projectiles over billions of years. Here we report the first discovery of an iron meteorite fragment from the Chang'e-5 lunar soil, which consists mainly of martensite (quenched from taenite), kamacite, and schreibersite, with a trace of pentlandite. The meteorite fragment is Ni- and P-rich, S-poor, and based on its mineral chemistry and bulk composition, can be classified into the IID-group, a rare and carbonaceous group of iron meteorite originating in the outer Solar System.

Surges in volcanic activity on the Moon about two billion years ago.

The history of mare volcanism critically informs the thermal evolution of the Moon. However, young volcanic eruptions are poorly constrained by remote observations and limited samples, hindering an understanding of mare eruption flux over time. The Chang'e-5 mission returned the youngest lunar basalts thus far, offering a window into the Moon's late-stage evolution.

Non-KREEP origin for Chang'e-5 basalts in the Procellarum KREEP Terrane.

Mare volcanics on the Moon are the key record of thermo-chemical evolution throughout most of lunar history. Young mare basalts-mainly distributed in a region rich in potassium, rare-earth elements and phosphorus (KREEP) in Oceanus Procellarum, called the Procellarum KREEP Terrane (PKT)-were thought to be formed from KREEP-rich sources at depth. However, this hypothesis has not been tested with young basalts from the PKT.