中国地质科学院地质研究所龙涛团队研究了月球背面玄武岩来源的同位素和成分限制。该研究于2025年2月27日发表在《科学》杂志上。
月球上的火山活动产生了地表玄武岩沉积物，记录了月球内部的过程。嫦娥六号任务从月球远端的南极艾特肯盆地（SPA）取回了样本。研究组分析了嫦娥六号收集的玄武岩碎片，发现它们的成分类似于阿波罗任务之前采集的低钛玄武岩。
U-Pb测年表明玄武岩年龄为2823.0±5.9 Ma，源238U/204Pb比值（μ值）为480±56。这个高μ值表明，该源包含在月球岩浆海洋（LMO）结晶后期形成的物质。结果与LMO模型一致，但嫦娥六号玄武岩偏离了阿波罗任务样本中μ值较高的年轻玄武岩的趋势。研究组认为，这表明SPA撞击对地幔进行了LMO后的改造。
附：英文原文
Title: Isotopic and compositional constraints on the source of basalt collected from the lunar far side
Author: Xiaochao Che, Tao Long, Alexander Nemchin, Shiwen Xie, Le Qiao, Zengsheng Li, Yiyi Ban, Runlong Fan, Chun Yang, Dunyi Liu
Issue&Volume: 2025-02-27
Abstract: Volcanism on the Moon has produced surface basalt deposits, which record lunar interior processes. The Chang’e-6 mission retrieved samples from the South Pole-Aitken basin (SPA) on the Moon’s far side. We analyze basalt fragments collected by Chang’e-6, finding their composition resembles low-Ti basalts previously sampled by the Apollo missions. U-Pb dating indicates a basalt age of 2823.0 ± 5.9 Ma and a source 238U/204Pb ratio (μ-value) of 480 ± 56. This high μ-value indicates that the source contained materials that formed during late stages of lunar magma ocean (LMO) crystallization. The results are consistent with the LMO model, but the Chang’e-6 basalt deviates from the trend in Apollo mission samples of younger basalts having higher μ-values. We suggest this indicates post-LMO modification of the mantle by the SPA impact.
DOI: adt3332
Source: https://www.science.org/doi/10.1126/science.adt3332