【新华社】月球“休眠”为何还有火山喷发？嫦娥六号样品揭秘

Core Viewpoint - Recent research indicates that the Moon, previously thought to be "dormant" for 3 billion years, has experienced volcanic activity during this period, challenging existing beliefs about lunar evolution [2][3]. Group 1: Research Findings - The Chang'e 5 and Chang'e 6 missions returned basalt samples that are 2 billion and 2.8 billion years old, respectively, confirming volcanic eruptions occurred during the Moon's "dormant" phase [2]. - A systematic study of the Chang'e 6 samples revealed two types of basalt formed around 2.8 and 2.9 billion years ago, with distinct compositions and depths of origin [3]. - The study identified "ultra-low titanium basalt" from deep within the lunar mantle (over 120 kilometers) and "low titanium basalt" from shallower depths (60 to 80 kilometers) [3]. Group 2: Mechanisms of Volcanic Activity - Traditional theories suggested that late lunar volcanic activity was linked to water-rich or radioactive heat sources, but the samples from Chang'e missions disproved this, showing dry and lacking radioactive elements [3]. - A new thermal dynamic mechanism was proposed, indicating that as the Moon cooled, magma became trapped in the shallow mantle, leading to partial melting and subsequent volcanic eruptions [3]. Group 3: Implications and Future Research - Analysis of global lunar remote sensing data revealed a significant change in volcanic heat dynamics around 3 billion years ago, shifting from diverse heat sources to a dominant upward heat transfer mechanism [4]. - The chemical characteristics of late volcanic rocks on the Moon's near side are similar to those of the Chang'e 5 basalt, while the far side is more akin to the ultra-low titanium basalt from Chang'e 6, suggesting compositional differences in the lunar mantle [4]. - This research not only enhances understanding of the Moon's thermal evolution history but also provides insights into volcanic activity mechanisms on other small, airless celestial bodies [4].