Youngest ever lavas dated from Moon

Researchers at The University of Manchester, have been involved in an international collaboration to analyse the age and history of some of the Moon’s youngest lava flows. The rock samples were collected by the Chinese National Space Agency during the robotic Chang’e-5 mission, which marked the first time any nation had collected rocks from the Moon since 1976.

The new research, published in the journal Science, determined the basaltic volcanic rocks, collected as part of China’s Chang’e-5 Moon landing in December 2020, were two billion years old – one billion years younger than any other dated basaltic lava from the Moon. The findings are significant as they present a new mystery to solve on 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.

The lead group at the Beijing SHRIMP Center in China sorted through allocated material to pick out ~2 mm fragments of rocky material, which they then analysed using a range of laboratory analytical techniques.

Co-lead international author Professor Alexander Nemchin, from Curtin University’s Space Science and Technology Centre in the School of Earth and Planetary Sciences, says “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 7 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”.

Dr Romain Tartese, a Dame Kathleen Ollerenshaw and STFC Ernest Rutherford Research Fellow at 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 2 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”

Prof Katherine Joy, a Royal Society University Research Fellow at The University of Manchester, said: “It was a privilege to work on an international science team to investigate these newly collected Moon rocks as these samples are hugely significant within the context of renewed lunar exploration efforts. Whilst exciting new findings are coming out of the Chang’e 5 material, we are also looking forward to the next Chang’e 6 robotic sample return mission, which will likely take place later this year or early next year, returning the first samples from the lunar farside.”

The research was carried out in collaboration with experts from the International Lunar and Planetary Research Center of China, The Beijing SHRIMP Center, The Australian National University, Washington University in St Louis, Notre Dame University, Brown University, and the University of Colorado, in the United States of America, The University of Manchester in the United Kingdom, and the Swedish Museum of Natural History.

The paper, Age and composition of the youngest basalts on the Moon returned by the Chang’e-5 mission, is published in Science.

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