rare rock fragments
A Chinese research team has precisely dated the formation of the Moon’s Apollo Basin to 4.16 billion years ago through high-precision analysis of lunar soil collected by the Chang’e-6 mission. The finding extends the timeline of the Moon’s “impact storm” by at least 100 million years, providing new insights into the evolution of the Earth-Moon system. The results were published on Wednesday in the international journal Nature Astronomy, China Central Television reported.
Led by Academician Xu Yigang of the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, the research team identified three rare rock fragments, ranging from 150 to 350 micrometers, within a 3.5-gram lunar soil sample. Formed as impact-melted rocks during the Apollo Basin’s creation , these fragments serve as ideal “rock clocks” for recording impact events.
By dating these fragments and integrating remote- sensing imagery and geochemical data, the team confirmed the Apollo Basin’s formation at 4.16 billion years ago, the report said.
The Moon’s surface is dotted with massive impact basins, most of which are remnants of collisions with small celestial bodies around 3.8 billion years ago. Scientists have long debated whether the solar system’s “impact storm” tapered off gradually or spiked suddenly in intensity between 4 and 3.8 billion years ago—a controversy driven by the lack of precise age data for key lunar basins.
Located within the Moon’s South Pole-Aitken Basin, the Apollo Basin is the region’s largest secondary impact structure, and its formation age may mark the onset of the Moon’s late-stage impact events.
This study not only pushes the onset of the lunar “impact storm” back by at least 100 million years but also shows that impact intensity declined gradually, rather than spiking abruptly. These findings are set to reshape our understanding of the Earth-Moon system’s evolutionary history, CCTV reported.
In July, the Global Times learned from the Chinese Academy of Sciences that four studies on the lunar samples from the far side of the moon returned by China’s Chang’e-6 mission have revealed respectively the lunar far side’s magmatic activity, ancient magnetic field, mantle water content, and mantle evolution, unveiling the evolutionary history of moon’s far side for the first time.
The findings of the four studies were published as cover articles in the international journal Nature, according to the CAS.
They revealed volcanic activity on the lunar far side around 4.2 billion and 2.8 billion years ago, lasting for at least 1.4 billion years. They also obtained the first paleomagnetic data from the far side, showing that the lunar magnetic field may have rebounded around 2.8 billion years ago, suggesting the lunar dynamo did not decline steadily but experienced fluctuations.