我国科学家揭秘月球“晚年”为何还有火山喷发

Core Insights - The study challenges the long-held belief that the Moon became "dormant" 3 billion years ago, revealing that volcanic activity continued much later, supported by samples from China's Chang'e 5 and 6 missions [1][2] - A new heat-driven mechanism is proposed for the Moon's volcanic activity, indicating that magma was trapped in the upper mantle and could trigger eruptions through heat transfer [2][3] Group 1: Research Findings - The research team identified two types of basalt from the Chang'e 6 samples, formed around 2.8 billion and 2.9 billion years ago, with distinct compositions and sources [1] - One type is "ultra-low titanium basalt" from deep within the Moon's mantle (over 120 kilometers), while the other is "low titanium basalt" from a shallower mantle (60-80 kilometers) [1] - The study simulated high-temperature and high-pressure conditions to understand the formation of these basalt types, linking them to different layers formed from the cooling of the early lunar magma ocean [1] Group 2: Mechanism of Volcanic Activity - Traditional theories suggested that late lunar volcanic activity was linked to water-rich or radioactive heat-producing elements, but the samples disproved this, showing a "dry" source lacking radioactive elements [2] - The new mechanism suggests that as the Moon cooled, the lithosphere thickened, preventing deep magma from erupting and causing it to remain in the upper mantle, where it could melt partially and lead to eruptions [2] - Analysis of lunar remote sensing data indicated a significant change in the heat-driven mechanism around 3 billion years ago, shifting from a complex heat source to a dominant upward heat transfer mechanism [2] Group 3: Implications - This research not only updates the understanding of the Moon's thermal evolution history but also provides important references for explaining volcanic activity mechanisms on other small, airless celestial bodies [3]