Credit: © John Sibbick / Natural History Museum The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land—including the largest insects known to have inhabited the Earth. 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. For example, sea surface temperatures also rose about 18 degrees Fahrenheit (10 degrees Celsius) over a period beginning before the extinction and continuing into the early Triassic. "It is clear that whatever triggered extinction must have acted very quickly," says Burgess, the lead author of a paper that reports the results in this week's Proceedings of the National Academy of Sciences, "fast enough to destabilize the biosphere before the majority of plant and animal life had time to adapt in an effort to survive." Volcanic ash beds interlaced with Meishan marine rocks have tiny minerals called zircons that can be precisely dated with geochemical techniques, and the marine rocks carry scores of fossils that record the die-off and resurgence of life. The researchers pulverized rocks and separated out tiny zircon crystals containing a mix of uranium and lead. They then isolated uranium from lead, and measured the ratios of both isotopes to determine the age of each rock sample. From their measurements, the researchers determined a much more precise "age model" for the end-Permian extinction, which now appears to have lasted about 60,000 years—with an uncertainty of 48,000 years—and was immediately preceded by a sharp increase in carbon dioxide in the oceans. Explore further: Timeline of a mass extinction: New evidence points to rapid collapse of Earth’s species 252 million years ago 
 
 More information: "High-precision timeline for Earth's most severe extinction," by Seth D. Burgess, Samuel Bowring, and Shu-zhong Shen.
– Roughly 252 million years ago, an extreme animal die-off occurred: 70% of land animals and 96% of marine life were obliterated, in what's known as the Permian mass extinction. What scientists still don't exactly know is why (an asteroid? volcanic eruptions?), but they now know how long it took. And the answer is ... really, really fast. MIT researchers say the extinction period's duration clocked in at 60,000 years, plus or minus 48,000 years. As Phys.org puts it, that's "practically instantaneous, from a geological perspective." To get your geological periods and catastrophic disasters straight: The die-off signified the end of the Permian period and launched the start of the Triassic; the mass die-off of the dinosaurs happened much later, 66 million years ago at the Cretaceous period's close, when LiveScience reports 85% of life was wiped out. The researchers came to their conclusion by using cutting-edge dating techniques on tiny minerals known as zircons found in rocks in Meishan, China, that date to the period. But the rocks also held carbon dioxide data; from there, the researchers determined that a surge of the gas occurred 10,000 to 20,000 years before the die-off: Ocean acidification may have have occurred, and sea temps could have jumped as much as 50 degrees. But what was the source of the increased carbon dioxide that marked the beginning of the end? MIT researchers are now dating rocks from the Siberian Traps to determine if volcanic eruptions there could have been the culprit.