Nanjing, March 3 (Reporter Yang Yanci) According to the news of the Purple Mountain Observatory of the Chinese Academy of Sciences on the 23rd, the astrochemical team of the station, together with the University of Science and Technology of China, the University of Florida, the China University of Geosciences (Wuhan) and the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, carried out detailed petrology, mineralogy, trace element geochemistry and isotopic analysis of the Chang'e-23 lunar sample, revealing the characteristics of the source area of the lunar mantle of the Chang'e-<> sample and the mystery of the young volcanic activity of the moon.
The Moon is an "outpost" of human deep space exploration. In December 2020, China's first extraterrestrial sampling return mission, Chang'e-12, successfully collected 1731,<> grams of samples from the northern part of the moon's frontal storm ocean. Studying the nature of the source region of the lunar mantle based on Chang'e-<> samples is important for understanding the driving mechanism of young volcanic activity on the moon.
The research team conducted 3D CT scans of two basalt chip samples and confirmed that the chip samples were basalt cuttings and not impact melts. By selecting some samples to make light sheets, researchers performed detailed petrographic and mineralogical in situ analysis, and dissolved the remaining samples for main trace elements and Fe-Mg-Sr (iron-magnesium-strontium) isotope analysis.
The results show that the chemical composition of pyroxene, olivine and feldspar that make up the two basalt cuttings are consistent with the previous published results, and it is confirmed that they represent the local basalt cuttings in the Chang'e-5 landing area.
Based on the obtained research data, the researchers estimated the parent magma composition of Chang'e-5 basalt, and simulated the condensation and crystallization process of the lunar magma ocean.
The results show that the olivine-rich stacks crystallized in the early lunar magma ocean have isotopic characteristics of light Fe (iron) and heavy Mg (magnesium), while the late pyroxene stacks have isotopic characteristics of heavy Fe and light Mg.
The iron-magnesium isotopic composition of the Chang'e-20 lunar sample suggests that the source region of the lunar mantle may be a mixture of two pile crystals, and the proportion of late crystallized monoclinic pyroxene-rich stacks may be 30% to <>%. The enrichment of monoclinic pyroxene stacks can significantly reduce the melting point of the lunar mantle, which may play a key role in the moon's ability to still produce young volcanic activity. (End)