【中国新闻网】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 Viewpoint - The research team from the Chinese Academy of Sciences has discovered that the large impact event in the South Pole-Aitken Basin on the Moon led to the loss of moderately volatile elements in the mantle, providing crucial insights into the Moon's evolution and the causes of its dichotomy [4][5]. Group 1: Research Findings - The study utilized high-precision potassium isotope analysis of lunar soil samples collected by the Chang'e 6 mission, revealing that the basalt from the Chang'e 6 mission has a higher potassium-41/potassium-39 ratio compared to samples from the Apollo missions [4]. - The research 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 preferential escape of lighter isotopes like potassium-39 during the high-temperature and high-pressure conditions of the impact [5]. - The loss of volatile elements may make the rocks on the Moon's far side more difficult to melt, thereby reducing volcanic activity, which provides key clues for understanding the geological evolution history of the Moon's far and near sides [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 numerous impact craters and basins while significantly altering the surface's topography and chemical composition [5]. - The samples collected from the South Pole-Aitken Basin, the largest impact basin on the Moon, are critical for studying the effects of large impacts and their implications for the Moon's deep structure [5]. - High-precision isotope analysis can capture minute changes in isotope ratios, revealing information about early impact events, with the isotope systems of moderately volatile elements being particularly valuable for understanding the temperature, pressure, and material sources during impacts [6].