On April 10, the website of the Chinese Academy of Sciences reported that Professor Hu Sen and Lin Yangting from the Institute of Geology and Geophysics, Chinese Academy of Sciences, in collaboration with Professor Hui Hejiu's team from Nanjing University, utilized lunar samples brought back by Chang'e-6 to reveal for the first time that the water content in the lunar mantle on the far side is less than 2 micrograms/gram. This achievement provides critical constraints for discussing the spatiotemporal evolution of water in the lunar mantle.
Scientists reveal a "drier" lunar mantle on the far side through Chang'e-6 basalt
The water content of the lunar mantle has significant importance in revealing the origin of the Moon, magma activity, resource environmental effects, etc. The academic community generally believes that about 4.5 billion years ago, a Mars-sized celestial body collided with the primitive Earth, and the ejected material re-accreted to form the Moon. This is the starting point of the Moon - the giant impact hypothesis. In this extremely high-temperature collision event, it was expected that the Moon would be extremely poor in water. In recent 20 years, there has been controversy over whether the lunar mantle is rich or poor in water, and all published data have focused on the near side of the Moon.
The Chinese Chang'e-6 mission retrieved the world's first far-side samples from the Apollo Crater within the South Pole-Aitken Basin. The previously reported eruption age of the main period of Chang'e-6 basalt is 2.8 billion years. These basalts provide an important opportunity to study the spatiotemporal evolution of water in the lunar mantle.
The research team conducted source area water content studies on approved Chang'e-6 basalt debris samples. The results show that the water content in the lunar mantle source area of Chang'e-6 basalt is only 1 to 1.5 micrograms/gram, which is the lowest value among the published data, indicating that the lunar mantle source area of Chang'e-6 basalt is drier than the lunar mantle on the near side. The reason may be that the Aitken Basin impact event at the South Pole of the Moon transformed the water in the lunar mantle source area. This study provides critical constraints for the giant impact hypothesis of the Moon's origin and its subsequent evolution.
On April 9, relevant research results were published in Nature. The reviewers of Nature considered this to be a highly original study, and the research team performed foundational work on the water content of the lunar mantle for the first batch of far-side basalts. Another reviewer stated that this paper reports for the first time the water content in the lunar mantle on the far side and will become a milestone study on the water content in the lunar mantle on the far side.
Original article: https://www.toutiao.com/article/7491501728312033832/
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