Chang'e-6 mission reveals ancient volcanic and magnetic secrets from Moon's farside

Chang'e-6 mission reveals ancient volcanic and magnetic secrets from Moon's farside
by Riko Seibo
Tokyo, Japan (SPX) Jul 14, 2025

The Moon's near and far sides differ dramatically in terrain, crust, and volcanic history-a mystery that has long perplexed scientists. This disparity is now better understood thanks to China's Chang'e-6 mission, which launched on May 3, 2024, and returned 1,935.3 grams of lunar material from the South Pole-Aitken Basin (SPA) on June 25, 2024. The SPA, a 2,500-kilometer-wide structure, is the oldest, deepest, and largest impact basin on the Moon.

Earlier research suggested that the SPA formed about 4.25 billion years ago in a cataclysmic impact, but the broader geological implications remained elusive. Now, research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories (NAOC), Nanjing University, and other institutions have made four major breakthroughs. These results, detailed in four cover stories in Nature, offer new clarity on the Moon's internal processes.

According to Prof. WU Fuyuan of IGG and the Chinese Academy of Sciences, the collective findings of the Nature papers mark the first time the SPA's impact consequences have been fully revealed.

One key discovery is the identification of two volcanic episodes on the farside, occurring around 4.2 billion and 2.8 billion years ago. This points to prolonged volcanic activity lasting at least 1.4 billion years-far longer than previously recognized.

Another study measured paleomagnetic intensities in basalt fragments, detecting a magnetic resurgence 2.8 billion years ago. This indicates that the Moon's magnetic dynamo did not decline smoothly but instead exhibited intermittent rebounds.

Analysis of water content in the SPA samples showed a drier mantle on the farside compared to the nearside. This asymmetry in volatiles reveals previously unknown differences in the Moon's deep interior.

Geochemical signatures also uncovered evidence of an ultra-depleted mantle source, suggesting either a primordial origin or depletion driven by large impacts. These results underscore how major collisions have shaped the Moon's internal composition.

The first sample assessment, led by NAOC, cataloged the samples' physical, chemical, and mineral traits. Subsequent analysis by the Guangzhou Institute of Geochemistry confirmed the 2.8-billion-year-old volcanism and its link to a depleted mantle, while IGG precisely dated the SPA impact at 4.25 billion years.

Together, these studies not only deepen our understanding of the Moon's farside but also demonstrate the Chang'e-6 mission's pivotal role in refining theories of planetary formation.

Research Report:Ultra-depleted mantle source of basalts from the South Pole-Aitken basin