Last December, the Chinese lunar lander Chang'e-5 returned to Earth with the first rocks and dust collected from the Moon since 1976. Researchers studying these precious samples have used advanced scientific instruments to determine their age and concluded them to be the youngest rocks ever found on the Moon, reshaping the timeline of volcanic activity on our only natural satellite.
This new research is among the first to be published from the pioneering Chang'e-5 mission, the completion of which made China just the third country to bring lunar samples back to Earth, after the US and the Soviet Union. The rocks collected during the Apollo and Luna missions of the 1960s were all at least three billion years old, indicating to geologists that the Moon had not seen volcanic activity since.
However, remote images recently taken of the lunar surface have suggested there are far younger rocks than this to be found. The Chang'e-5 mission, designed to gather rocks from some of the youngest volcanic surfaces on the Moon, provided the perfect opportunity to confirm these suspicions.
An international team of scientists used large mass spectrometers to study the chemistry of the Chang'e-5 samples and analyze the decay of radioactive elements within them, determining their age to be around 2 billion years old.
“After analyzing the chemistry of the new Moon rocks collected as part of China’s recent mission, we determined the new samples were about two billion years old, making them the youngest volcanic rocks identified on the Moon so far," says study author Professor Alexander Nemchin, from Australia's Curtin University.
Not only does this shake up the timeline around how recently the Moon was volcanically active, it confirms the effectiveness of the remote observation techniques, which bodes well for the study of other planets.
“These results confirm what experts had long predicted based on remotely obtained images of the Moon and raise further questions as to why these young basalts exist,” says study author Professor Gretchen Benedix, from Australia's Curtin University. “The task will now turn to finding a mechanism that will explain how this relatively recent heating of the Moon may have supported the formation of basaltic magmas with temperatures exceeding 1,000 degrees Celsius (1,832 °F) – and ultimately help researchers improve age dating of the entire Solar System.”
As part of its burgeoning space program, China has further lunar missions in the works with Chang’e-6, 7 and 8 all expected to lift off this decade, exploring the Moon for resources and the potential for a lunar science base.
The research was published in the journal Science.
Sources: Curtin University, The Conversation