When China’s Chang’e-5 lunar spacecraft returned to Earth last December, it brought with it the first sample of moon rocks collected in more than 40 years. An international team of researchers has worked hard to analyze part of this precious specimen and found that it contains the youngest volcanic lunar material ever discovered.
The team of researchers found that this specimen was about 1.97 billion years old. Although the Moon is volcanically inactive today, its 4.5 billion-year history has had significant volcanic activity that has shaped its development, such as lava that flows across its surface and forms lava tubes beneath the surface.
Knowing the exact date of sampling is important for accurately dating the Moon’s geological history in absolute terms. “Planetary scientists know that the more craters there are on the surface, the older it is; the fewer craters there are, the younger the surface will be. That’s a good relative determination,” said one of the researchers, in St. Louis Washington. Brad Jolliff of the University explained, in a Statement. “But to put full age dates on that, samples have to be taken from those surfaces.”
Previous volcanic samples from the Moon, such as those collected during the Apollo missions, were more than 3 billion years old. And researchers have been able to date impact craters, where the Moon was hit by asteroids or comets less than 1 billion years old. But there was a gap between these two periods which has now been filled.
“In this study, we got a very accurate age of around 2 billion years, plus or minus 50 million years,” Joliff said. “It’s an unprecedented result. In terms of planetary timing, it’s a very accurate determination. And it’s good enough to differentiate between different formulations of chronology.”
This understanding is useful not only for knowing about the Moon. It can also teach us about the rocky planets in our solar system and beyond. “The Apollo samples gave us several surfaces that we were able to date and correlate with crater density,” Jolliff explained. “This cratering chronology has been extended to other planets – for example, to Mercury and Mars – to say that surfaces with a certain density of craters have a certain age.”
The findings are published in the journal Science.