Moon's crust formed from violent impacts, rocks brought back from surface by astronauts reveal

Researchers made new discoveries using rocks brought back from the Moon 50 years ago

Large parts of the surface of the Moon were forced in huge impact events, a new study has found.

The research used rocks brought back from the Moon almost 50 years ago to overturn the idea that collisions had only destroyed parts of the surface, and that the lunar crust was made when magma rose from the planet's interior.

Instead, it suggests that the kind of spectacular collision that wiped out the dinosaurs might actually have formed the ancient rocks that are still found on the Moon today.

Having conducted new analysis of a sample collected by Nasa astronauts during the Apollo 17 mission in 1972, a group of scientists have found that the rock contains evidence that it was formed at incredibly high temperatures.

This would have reached in excess of 2,300C, which the scientists say could have been achieved by the melting of the outer layer in a very large impact event.

Dr James Darling, of the University of Portsmouth, said: "The discovery reveals that unimaginably violent impact events helped to build the lunar crust, not only destroy it.

"Going forward, it is exciting that we now have laboratory tools to help us fully understand their effects on the terrestrial planets."

The team used a technique called electron backscatter diffraction to discover the former presence of cubic zirconia, a mineral phase that would only occur in rocks heated to above 2300C.

Radiometric age dating of the grain at the Swedish Museum of Natural History also revealed that it formed more than 4.3 billion years ago.

As well as helping tell the story of the formation of the Moon, the discovery could give scientists more information about how our own planet came about, scientists said.

"Rocks on Earth are constantly being recycled, but the Moon doesn't exhibit plate tectonics or volcanism, allowing older rocks to be preserved," said Dr. Lee White from the Royal Ontario Museum.

"By studying the Moon, we can better understand the earliest history of our planet. If large, super-heated impacts were creating rocks on the Moon, the same process was probably happening here on Earth".

Researchers from the universities of Portsmouth, Manchester and The Open University, were funded by the Science and Technology Facilities Council (STFC) for the study.

The research, titled 'Evidence of extensive lunar crust formation in impact melt sheets 4,330 Myr ago', is published in Nature Astronomy.

Additional reporting by agencies