中国科学院地球化学研究所机构知识库

The Chang’E-6 (CE-6) mission successfully achieved return of the first samples from the far side of theMoon. The sampling site of CE-6 is located in the South Pole-Aitken (SPA) basin—the largest, deepest andoldest impact basin on the Moon. The 1935.3 g of CE-6 lunar samples exhibit distinct characteristicscompared with previous lunar samples. This study analyses the physical, mineralogical, petrographic andgeochemical properties of CE-6 lunar scooped samples. The CE-6 soil has a significantly lower bulk density(0.983 g/cm3) and true density (3.035 g/cm3) than the Chang’E-5 (CE-5) samples. The grain size of theCE-6 soil exhibits a bimodal distribution, indicating a mixture of different compositions. Mineralogically,the CE-6 soil consists of 32.6% plagioclase (anorthite and bytownite), 19.7% augite, 10% pigeonite and 3.6%orthopyroxene, and with low content of olivine (0.5%) but high content of amorphous glass (29.4%).Geochemically, the bulk composition of CE-6 soil is rich in Al2O3 (14%) and CaO (12%) but low in FeO(17%), and trace elements of CE-6 soil such as K (∼630 ppm), U (0.26 ppm), Th (0.92 ppm) and rare-earthelements are significantly lower than those of the lunar soils within the Procellarum KREEP Terrane. Thelocal basalts are characterized by low-Ti (TiO2, 5.08%), low-Al (Al2O3 9.85%) and low-K (∼830 ppm),features suggesting that the CE-6 soil is a mixture of local basalts and non-basaltic ejecta. The returned CE-6sample contains diverse lithic fragments, including local mare basalt, breccia, agglutinate, glasses andleucocrate. These local mare basalts document the volcanic history of the lunar far side, while thenon-basaltic fragments may offer critical insights into the lunar highland crust, SPA impact melts andpotentially the deep lunar mantle, making these samples highly significant for scientific research.