China's fresh moon rocks are younger than the Apollo samples and no one knows why
New analyses of moon rocks delivered to Earth by China's Chang'e 5 mission confirm that volcanism occurred later than previously known, but also deepen the mysteries surrounding that activity.
China's Chang'e 5 spacecraft collected 3.81 pounds (1.73 kilograms) of lunar dust and rocks from a region called Oceanus Procellarum on the near side of the moon in December 2020. The mission team targeted this landing area because of its apparent lower density of craters, suggesting it was significantly younger than areas sampled by the Apollo and Soviet Luna missions.
The samples were first processed and catalogued, and a first batch of samples were approved for release in June. Since then, various teams of scientists have since been working to learn what the rocks can tell us about the moon and the history of our solar system. ...
A first paper published in Science in early October dated a fragment of the samples at about 1.97 billion years old. Now a second, published in Nature on Oct. 19, uses a similar dating method but on a different sample, gives an age of 2.03 billion years — very close, geologically speaking. The pair of dates confirms that volcanic activity was taking place in this area of the moon around a billion years after the areas sampled by the Apollo and Soviet Luna missions had become geologically dead. ...
Why the mantle beneath this patch of the moon was still active relatively late in the moon's history remains a mystery, however. ...