月幔挥发性元素为何丢失？嫦娥六号月壤高精度同位素分析揭秘

Core Insights - The research team from the Chinese Academy of Sciences has discovered that the impact event of the South Pole-Aitken Basin on the Moon led to the loss of moderately volatile elements in the mantle, providing key information for understanding the effects of large impacts on lunar evolution and the causes of the Moon's dichotomy [1][5]. Group 1: Research Findings - The study published in the Proceedings of the National Academy of Sciences indicates that the Chang'e 6 lunar basalt samples exhibit a higher potassium-41/potassium-39 ratio compared to Apollo samples from the Moon's near side [2]. - The research team confirmed that the impact event altered the potassium isotope composition of the mantle, resulting in the loss of potassium and an increase in isotope ratios due to the escape of lighter isotopes during the high-temperature and high-pressure conditions of the impact [5][7]. - The loss of volatile elements may make the rocks on the far side of the Moon more difficult to melt, thereby reducing volcanic activity, which provides critical clues for understanding the geological evolution history of the Moon's far side [5]. Group 2: Implications of the Research - The study highlights that asteroid impacts have been the primary external geological process shaping the Moon since its formation, creating impact craters and basins that significantly alter the surface topography and chemical composition [7]. - The high-precision isotope analysis used in this research can capture minute changes in isotope ratios, revealing information about early impact events, including temperature, pressure, and material sources during the impact process [7].