Samples of Moon rock collected by China’s Chang’e-5 mission have confirmed that lava was still flowing on our closest celestial neighbour as recently as 1.97 billion years ago.
Analysis from researchers at The University of Manchester determined that the basaltic volcanic rocks were two billion years old: one billion years younger than any other dated basaltic lava from the Moon.
They believe this presents a new mystery about how such a small rocky planetary body could retain enough heat to enable melting of its interior, and volcanic eruptions at its surface, two and a half billion years after it formed.
Dr Romain Tartese from The University of Manchester, said: “Continuous laboratory developments over the past decade, initially developed for analysis of lunar samples returned half a century ago by the Apollo missions, have allowed colleagues in China to extract crucial age information from these millimetre-sized particles scooped on the Moon’s surface.
“These young eruption ages are really exciting as it is a complete mystery how the interior of the Moon stayed hot enough to generate such young lava flows only two billion years ago.”
Dr Joshua Snape, a Royal Society University Research Fellow at The University of Manchester, said: “Samples like this allow us to not only understand the history of the Moon, but to also relate the age of the geological unit they were collected from to the number and size of impact craters that scar its surface. Combining these records helps us to calibrate the rates of impact cratering across the wider Solar System, helping us understand the geological records of other planetary bodies”
Co-lead international author Professor Alexander Nemchin, from Curtin University, said: “This was a truly international effort when having people in different time zones gave us ability to work on the project 24 hours a day, seven days a week. Some of us on the team still remember excitement of working with the samples nobody ever seen before from the Apollo era, others experienced this for the first time”.