Chang'e 5 sample study reveals the Mystery of Lunar Young Volcano activity
CTOnews.com March 24, according to the website of the Zijinshan Observatory of the Chinese Academy of Sciences, the astrochemistry team of the Zijinshan Observatory of the Chinese Academy of Sciences recently joined forces with the University of Science and Technology of China, the University of Florida, the Chinese University of Geosciences (Wuhan) and the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences. Detailed petrographic, mineralogical, trace element geochemistry and Fe-Mg-Sr isotopic analysis of the Chang'e-5 lunar samples returned from China have been carried out to reveal the characteristics of the lunar mantle source region of the Chang'e-5 sample and the mystery of lunar young volcanic activity.
According to reports, the moon is the "outpost" for human deep space exploration. In December 2020, China's first extraterrestrial sampling mission "Chang'e V" successfully returned 1731 grams of samples from the northern part of the lunar frontal storm. The study of the properties of the lunar mantle source region based on the Chang'e-5 sample is very important to understand the driving mechanism of lunar young volcanic activity.
The research team carried out three-dimensional CT scans of two basalt cuttings samples (CE5C0800YJYX038) to confirm that the cuttings samples were basalt cuttings, not impact melts. Select some samples to make X-ray film, carry out detailed petrographic and mineralogical in-situ analysis, and dissolve the remaining samples to carry out major and trace elements and Fe-Mg-Sr isotope analysis.
The results show that the chemical compositions of pyroxene, olivine and feldspar which make up the two basalt cuttings are consistent with the results published by predecessors, which confirm that they represent the local basalt cuttings in the Chang'e-5 landing area.
CTOnews.com learned from the website of Zijinshan Observatory that based on the major and trace elements and Fe-Mg isotope data obtained, the research team estimated the parent magma composition of Chang'e-5 basalt and simulated the condensation crystallization process of lunar magma. The results show that the olivine-rich heap crystals crystallized in the early magmatic ocean have the isotope characteristics of light Fe and heavy Mg, and the late rich pyroxene stack crystals have the isotope characteristics of heavy Fe and light Mg.
The Fe-Mg isotopic composition of the Chang'e-5 lunar sample indicates that the lunar mantle source may be a mixture of two kinds of heap crystals, and the proportion of late crystallization of clinopyroxene-rich heap crystals may be 20-30%. The enrichment of clinopyroxene heap crystals can significantly reduce the melting point of the lunar mantle, which may play a key role in the young volcanic activity of the moon.
