Rock & Gem

Volcanic Activity on the Moon Continued Far Longer than Thought


Compared to Earth, the Moon has been considered geological­ly dead for billions of years. In other words, while Earth has a hot, hot core, volcanic activity and active plate tectonics, our much smaller Moon was thought to have cooled fairly quickly, reducing any potential for volcanism relatively soon after its formation. That idea is now being re-evaluated thanks to samples from China’s Chang’e 5 lunar probe.

In December 2020, this unmanned probe returned samples from the surface of the Moon to Earth for the first time in about 50 years. Scientists have now examined those samples and the results are surprising.

Samples of lunar rock returned by the US Apollo program and by the former Soviet Union’s Luna missions showed evidence of volcanic activity on the Moon some 3.8 to 3 billion years ago. But samples returned by Chang’e 5 have been dated at less than 2 billion years old, thus representi­ng some of the youngest basaltic lavas on the surface of the Moon. If the internal core of the Moon cooled relatively quickly after formation, what could have driven continued volcanic activity on its surface? Suggestion­s include “tidal heating” because of the pull and tug of gravitatio­nal forces from Earth, radioactiv­e mineralogy that could have supplied the heat to melt rock in the Moon’s mantle or impacts from asteroids and comets.

Stay tuned for further analyses and conclusion­s from “the youngest-ever lava flow dated from the Moon,” per Katherine Joy of the University of Manchester in the UK.

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