“There are strong similarities with zircon from the types of rocks that predominated for the following 1.5 billion years, suggesting that it took the Earth a long time to evolve into the planet that we know today.” The team conducted a forensic study of the grains looking for clues to their formation.

In a related article on geologic ages (Ages), we presented a chart with the various geologic eras and their ages.

In a separate article (Radiometric dating), we sketched in some technical detail how these dates are calculated using radiometric dating techniques.

will shortly be launching a new section to the Journal, Perspectives in Petrology.

This will feature articles on the latest developments from across the sub-disciplines of petrology, authored by internationally recognized experts.

But pinning down the duration of the Permian mass extinction will help researchers refine its potential trigger mechanisms, said Seth Burgess, lead study author and a geochemist at MIT.

"Whatever caused the extinction was really rapid, or the biosphere reached some critical threshold," Burgess told Live Science.Earth 4.4 billion years ago was flat and almost entirely covered in water with just a few small islands, new research suggests.Scientists came to the conclusion after analysing tiny zircon mineral grains from a region of Western Australia containing the oldest rocks ever found.It took only 60,000 years to kill more than 90 percent of all life on Earth, according to the most precise study yet of the Permian mass extinction, the greatest die-off in the past 540 million years.The new timeline doesn't reveal the culprit behind the die-off, though scientists have several suspects, such as volcanic eruptions in Siberia that belched massive quantities of climate-changing gases.The latest high-tech equipment permits reliable results to be obtained even with microscopic samples.