radiometric dating

Led by experts from the Chinese Academy of Sciences, researchers used radiometric dating to determine the age of the volcanic rock.

The breakthrough in dating the fossils was due to the work of the lead author of the paper, Pembrokeshire-born PhD student Tony Clarke, who has been working on radiometric dating at Curtin University in Perth, Western Australia.

When that lunar magma ocean cooled, that's when the zircon crystals could finally form, locking in chemical signatures that the Field Museum scientists can now measure with radiometric dating technology.

After determining the materials in the sample and performing radiometric dating, the researchers concluded that the oldest crystals are about 4.46 billion years old.

"Radiometric dating works a little bit like an hourglass," said the Field Museum's Philipp Heck, the study's senior author.