Oldest fragment of the Earth’s crust found

Credit: John Valley, University of Wisconsin

Researchers have unearthed crystals that are 4.4 billion years old in Australia.

The zircon crystals were discovered in the Jack Hills area of Western Australia in 2001 and recent research has confirmed their age as being just 100 million years younger than the Earth itself.

The crystals are dated in two ways. Firstly, scientists decipher how much of the uranium in the material had decayed into lead. Secondly, a technique known as atom-probe tomography allows the scientists to identify the age of individual atoms within the element.

The crystals themselves are only twice the length of a human hair but the discovery itself is remarkable as due to weathering and erosion, the vasty majority of rocks and crystals found on the Earth are much, much younger.