Newly discovered evidence shows that the moon’s crust may have formed directly as a result of giant meteorite impacts.
New research published Monday in the journal Nature Astronomy shows one of nature’s most destructive events led to the creation of the moon’s unusual crust.
Led by the Royal Ontario Museum, a group of astronomers say the most ancient parts of the moon’s crust appears to have formed during the time of frequent massive meteorite impacts.
“Rocks on Earth are constantly being recycled, but the Moon doesn’t exhibit plate tectonics or volcanism, allowing older rocks to be preserved,” explains Dr. Lee White, Hatch Postdoctoral Fellow at the ROM. “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”.
The team noted that rock samples captured during the Apollo missions in the 1960s and 1970s show remarkable variety in terms of geology. The variations found contain mineralogical evidence that it formed at incredibly high temperatures (in excess of 2300 °C/ 4300 °F), which is only achievable by the melting of the outer layer of a planet in a large impact event.
“By first looking at this rock, I was amazed by how differently the minerals look compared to other Apollo 17 samples,” says Dr. Ana Cernok, Hatch Postdoctoral Fellow at the ROM and co-author of the study. “Although smaller than a millimetre, the baddeleyite grain that caught our attention was the largest one I have ever seen in Apollo samples. This small grain is still holding the evidence for formation of an impact basin that was hundreds of kilometres in diameter. This is significant, because we do not see any evidence of these old impacts on Earth.”