Chang’e-5 samples reveal age of young moon rocks

These are the first scientific results published as part of the mission, and one of its goals was to return Earth’s rocks from some of the smaller volcanic surfaces on the Moon.

It is an exceptional result. In terms of planetary geology, it’s a very accurate history, Brad Jolev, of Washington University in St. Louis, said in a statement released by the foundation.

Relative youth

The Moon formed about 4.5 billion years ago, about the same time as the Earth, which it orbits.

However, unlike our planet, it is not subject to the processes of erosion and plate tectonics, phenomena that modify the Earth’s surface and lead to the erasure of impact craters over time. So the surface of the Moon has remained largely unchanged for tens of millions of years.

Even today, scientists have used these craters to estimate the ages of different regions of the Moon, based in part on how the region is marked with craters. Thus, the more pits there are in an area, the older it is, and the fewer pits there are, the smaller the surface.

The surface of the moon as observed by the Galileo probe in 1992.

Photo: NASA/JPL/USGS

It is relative dating, but to determine the absolute ages it is necessary to obtain samples from these surfaces., says Professor Golev. And it is precisely this gap that the current work fills.

This more accurate assessment will allow for better calibration of the instruments used to determine the chronology of lunar geology. All igneous rocks collected by Apollo were more than 3 billion years old. And all the small impact craters whose age has been determined from the analysis of other samples are younger than a billion years old. So Chang’e-5 samples fill an important gapProfessor Jolev explains.

This sample fills a gap of 2 billion years.

Details of this analysis are published in the journal Science (A new window) (in English).