月球背面演化历史首次揭开

Core Insights - The Chang'e 6 mission has achieved significant milestones in lunar exploration, including the first-ever sample collection from the far side of the Moon, enhancing understanding of lunar evolution [1][2][3] Group 1: Research Achievements - Four key research findings from the Chang'e 6 mission were published as cover articles in the journal Nature, revealing insights into lunar volcanic activity, ancient magnetic fields, water content in the mantle, and mantle evolution characteristics [1] - The Chang'e 5 mission previously filled gaps in lunar evolution research by discovering volcanic activity dating back 2 billion years, extending the timeline of lunar volcanic activity by 1 billion years [2] - The Chang'e 6 mission landed in the South Pole-Aitken Basin, a significant geological feature on the Moon's far side, which has been a primary scientific target for lunar exploration due to its unique characteristics [2][3] Group 2: Geological Insights - The research revealed two distinct periods of basaltic volcanic activity on the far side of the Moon, approximately 4.2 billion and 2.8 billion years ago, indicating sustained volcanic activity [3] - The study also provided ancient magnetic field data, suggesting that the Moon's magnetic field strength may have fluctuated around 2.8 billion years ago, challenging previous assumptions of a monotonically decreasing magnetic field [3] - Findings indicated that the water content in the far side's mantle is significantly lower than that of the near side, suggesting a dichotomy in the Moon's internal water distribution [3] Group 3: Mantle Composition Theories - The concept of a "super-depleted" mantle was introduced, indicating that the basalt samples from the far side originated from a region lacking incompatible elements, which are typically enriched in magma [4][5] - Two hypotheses were proposed regarding the formation of this super-depleted mantle: one suggests it originated from an undisturbed early lunar mantle, while the other posits that a massive impact event led to significant volcanic activity that altered the mantle's composition [4][5][6] - These discoveries provide unique insights into the early internal layering, cooling, and evolution of the Moon, contributing to understanding the significant differences between the Moon's near and far sides [6]