Researchers in the field in Isua, in southwest Greenland.
The Isua supracrustal belt, or I.S.B., as it is formally known, is an outcropping in southwest Greenland, right at the edge of the inland ice sheet.
Judging by the photographs I ve seen, the landscape there is immense and spare, a mix of rock and ice, clouds and sky.
But meteorite impacts, volcanic eruptions, tectonic turnover, and erosion have destroyed the oldest rocks.
To find material from the first five-hundred-million-odd years of Earth s existence, you have to take a trip to the Jack Hills, in Western Australia.
In themselves, zircons are common enough—they are often favored for jewelry—but what makes the ones from the Jack Hills special is that they are so extremely old, much older than the rocks they have been found in.