Reporters learned from the National Space Science Center of the Chinese Academy of Sciences on the 17th that its researchers systematically analyzed the exposure of anorthosite in the Apollo Basin on the moon, and successfully identified 51 pure anorthosite outcrops. They are distributed on the northern and southern edges, basin floor, and central peak ring structure of the Apollo Basin. This means that the lunar samples returned by Chang'e-6 from the Apollo Basin may contain plagioclase rocks representing the composition of the original lunar crust. The relevant research was published in the Journal of Geophysical Research: Planets. Why the front and back of the moon are different has always been a mystery. Scientists believe that the early moon was like a hot magma sea. When it cooled, calcium rich plagioclase rocks, due to their lighter weight, reached the surface and formed the oldest primitive lunar crust. Previously, the Apollo missions of the United States brought back samples of this plagioclase rock from the near side of the moon, but the representativeness of the samples was insufficient and the space coverage was limited. The academic community has been unclear whether the original lunar crust on the far side of the moon is the same as that on the front side. The Chang'e-6 sample was taken from the Apollo Basin on the far side of the moon. This area has been hit multiple times, the lunar crust is thin, the geology is very complex, and various substances are mixed together. This poses a significant challenge for scientists to interpret the samples of Chang'e-6. In this latest study, researchers used the multi band imaging instrument of the "Moon Goddess" lunar probe to obtain observation data, and compared the Chang'e-6 samples with known lunar rock databases, simulated spectra, and plagioclase rock samples brought back by the Apollo mission. They successfully found 51 rock outcrops with obvious plagioclase content. Analysis shows that the plagioclase in these areas has extremely high purity and belongs to pure plagioclase rock. "They are mainly exposed to the wall of the impact crater and the central peak formed later, as if they were excavated by the impact event," said Guo Dijun, the first author of the paper and associate researcher of the National Space Science Center of the Chinese Academy of Sciences. The landing area of Chang'e-6 is located in the lunar sea plain area in the southern Apollo Basin, surrounded by multiple impact craters containing pure plagioclase outcrops. Simulation calculations show that the material ejected from these impact craters containing plagioclase rocks accumulated over 10 centimeters thick at the landing site of Chang'e-6. This means that when Chang'e-6 is digging up lunar soil, it is highly likely to come across fragments from the oldest outer shell of the moon. Meanwhile, there are also some low calcium pyroxenes in the Apollo Basin that may have originated from the lunar mantle. Therefore, the "lunar specialties" brought back by Chang'e-6 are likely to contain both primitive lunar crust and mantle materials. Liu Yang, the corresponding author of the paper and a researcher at the National Space Science Center of the Chinese Academy of Sciences, said that this research has deepened our understanding of the distribution of the original lunar crust in the area on the back of the moon, and has provided important references for studying the early history of the moon, such as the cooling process of the lunar magma ocean, the evolution of the lunar crust and mantle. (New Society)