NASA and the Soviet space programme launched the first Moon sample-return missions fifty years ago. This included lunar rocks collected by robotic missions carried out as part of the Soviet Luna Program as well as those returned back to Earth by the Apollo crew.
These rocks’ study provided a wealth of information regarding the Moon’s composition, genesis, and geological past. In particular, researchers came to the conclusion that volcanic eruptions that occurred more than 3 billion years ago created the rocks.
The Revival Of Lunar Mission
Lunar exploration has experienced a comeback as a result of NASA and other space agencies sending robotic missions to the Moon in recent years (in preparation for crewed missions).
For instance, as part of the Chang’e programme, China has deployed numerous orbiters, rovers, landers, and sample-return missions to the Moon.
In a recent study, samples collected by the Chang’e-5 rover that date to 2 billion years old were examined by planetary scientists from the Chinese Academy of Sciences (CAS).
Their findings may shed important light on how recent volcanoes affected the lunar surface.
Su Bin, Yuan Jiangyan, and Chen Yi, members of the IGGCAS Laboratory of LIthospheric Evolution and Earth and Planetary Physics, headed the research team from the Institute of Geology and Geophysics of the Chinese Academy of Sciences (IGGCAS).
They were accompanied by scientists from the CAS Center for Excellence in Comparative Planetology and the Lunar and Planetary Science Institute (LPSI) at Nanjing University. On October 21, a report outlining their discoveries was published in the journal Science Advances.
What Was The Researchers’ Observation?
Scientists hypothesize that the Moon has been geologically dormant for the last 3 billion years based on materials collected during the Apollo and Luna missions.
However, the Chang’e-5 mission’s latest samples of lunar rock (which were brought back to Earth in 2021) were only 2 billion years old, proving that volcanic activity took place for at least a billion years longer than previously thought.
The heat that drove the Moon’s volcanism should have dissipated long before these eruptions took place because the Moon is a small, stony body.
Moon’s Volcanism
In the past, scientists hypothesized that late-stage volcanism may have been sparked by the lunar mantle’s elevated water content or radioactive element decay. This consensus has been disproven by the numerous analyses done on the samples the Chang’e-5 rover collected.
The CAS researchers deduced from their investigation that minerals in the mantle with low melting points may have permitted compression, resulting in youthful volcanism. In a recent CAS declaration, Prof. Chen stated:
“We should determine the temperature and pressure at which the nascent volcanism was created to better comprehend this challenge.” He explained that recent melting of the lunar mantle might be accomplished by either increasing temperature or decreasing melting point.
How Did The CAS Team Carry Out The Observations?
The CAS team analyzed 27 basalt clasts collected by the Chang’e-5 mission and those brought back by the Apollo missions using fractional crystallization and lunar mantle melting simulations.
They discovered that the younger Apollo magma samples contained larger concentrations of calcium oxide and titanium oxide.
These minerals, which melt more readily than older minerals accumulate in the lunar mantle, indicate that volcanism was gravitationally driven and caused the overturning of mantle material.
This research is comparable to what planetary scientists have just discovered about Mars. The red planet experienced thousands of eruptions on its surface millions of years ago, some of which produced the biggest volcanoes in the Solar System (like Olympus Mons).
What Is Scientists’ Observation?
Scientists hypothesize that when Mars’ interior chilled, it turned geologically lifeless. Recent research, however, suggests that there may still be some minor volcanic activity there.
Conclusion
The Chang’e-5 rover’s sample returns are consistent with the first workable theory for youthful volcanism on the Moon that is presented in this paper. Future planetary studies of the thermal and geological development of the Moon may benefit from this research.
According to their analysis, the mantle’s compression may have taken place at comparable depths and colder temperatures, which would still have resulted in volcanoes.
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