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. 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. "Having an accurate timeline for the events surrounding the mass extinction and the interval itself is extremely important, because it gives us an idea of how the biosphere responds." 
 
 The findings were published today (Feb. 10) in the journal Proceedings of the National Academy of Sciences. 
 
 Radioactivity and extinctions 
 
 The Permian mass extinction marks the end of the Permian geologic period, which ended approximately 252 million years ago. More than 96 percent of marine life and 70 percent of land species perished. By comparison, 85 percent of life died off during the dinosaur-killing extinction at the end of the Cretaceous period, 66 million years ago. [Wipe Out: History's Most Mysterious Extinctions] 
 
 "This is one of the fundamental inflection points in the trajectory of life on Earth," Burgess said. "It set the stage for the [rest] of evolution." 
 
 The best record of the Permian "great dying" is in Meishan, China. In past decades, hundreds of geologists collected and analyzed rocks in Meishan that date from before, during and after the Permian extinction. Researchers analyzed these rocks to better understand what caused the Permian event. 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. 
 
 Burgess and his co-authors improved the Meishan rock ages with the latest high-resolution, uranium-lead zircon dating techniques. Zircon traps minute amounts of naturally occurring radioactive uranium inside its crystal structure. Uranium decays into lead, and counting the ratio of the two elements provides an age estimate for the zircons. 
 
 The new dates show that the mass extinction started 251.941 million years ago (plus or minus 37,000 years) and ended at 251.880 million years ago (plus or minus 31,000 thousand years). The extinction's end also marks the start of the Triassic period, and coincides with the first fossil appearance at Meishan of a toothy, eel-like creature called Hindeodus parvus (a conodont, the source of the earliest teeth found in the fossil record). 
 
 Finding the killer(s) 
 
 The new timeline also provides greater accuracy for the environmental blows linked with the mass dying. For example, previous work has found an increase in carbon dioxide, a greenhouse gas, before the mass extinction began. In the Permian rocks, atmospheric carbon dioxide shifts are recorded as changes in the ratio of carbon isotopes. 
 
 The new study suggests the increase in carbon dioxide was sudden and short-lived, Burgess said. "It precedes the extinction by 20,000 years or so, and lasts 10,000 or 15,000 years. It was very short-duration event," he said. 
 
 But there are other potential tipping points for extinction beyond atmospheric greenhouse gases. 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. And the sudden carbon dioxide increase may have made the oceans more acidic. (A similar effect is happening in the present age due to carbon dioxide concentrations that have been rising because of man-made sources since the 1850s.) [Top 10 Ways to Destroy Earth] 
 
 "An accurate and high-precision age model gives us a reliable sounding [board] against which we can start comparing all of the other things that started happening with the mass extinction," Burgess said. 
 
 The research team is now applying the same age-dating technique to one of the main Permian mass extinction suspects, volcanic rocks from the Siberian Traps, one of the largest volcanic outpourings on Earth. 
 
 Email Becky Oskin or follow her @beckyoskin. Follow us @OAPlanet, Facebook and Google+. Original article at Live Science's Our Amazing Planet. ||||| Sea scorpions, the eurypterids, were probably the largest arthropods ever to have lived. They disappeared in the world’s most devastating mass extinction to date. 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. Multiple theories have aimed to explain the cause of what's now known as the end-Permian extinction, including an asteroid impact, massive volcanic eruptions, or a cataclysmic cascade of environmental events. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted. 
 
 Now researchers at MIT have determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years—practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought. 
 
 "We've got the extinction nailed in absolute time and duration," says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation." 
 
 In addition to establishing the extinction's duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life. 
 
 But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period's volcanic eruptions that are estimated to have covered over five million cubic kilometers. 
 
 "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." 
 
 Pinning dates on an extinction 
 
 In 2006, Bowring and his students made a trip to Meishan, China, a region whose rock formations bear evidence of the end-Permian extinction; geochronologists and paleontologists have flocked to the area to look for clues in its layers of sedimentary rock. In particular, scientists have focused on a section of rock that is thought to delineate the end of the Permian, and the beginning of the Triassic, based on evidence such as the number of fossils found in surrounding rock layers. 
 
 Bowring sampled rocks from this area, as well as from nearby alternating layers of volcanic ash beds and fossil-bearing rocks. After analyzing the rocks in the lab, his team reported in 2011 that the end-Permian likely lasted less than 200,000 years. However, this timeframe still wasn't precise enough to draw any conclusions about what caused the extinction. 
 
 Now, the team has revised its estimates using more accurate dating techniques based on a better understanding of uncertainties in timescale measurements. 
 
 With this knowledge, Bowring and his colleagues reanalyzed rock samples collected from five volcanic ash beds at the Permian-Triassic boundary. 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. 
 
 'Spiraling toward the truth' 
 
 The new timeline adds weight to the theory that the extinction was triggered by massive volcanic eruptions from the Siberian Traps that released volatile chemicals, including carbon dioxide, into the atmosphere and oceans. With such a short extinction timeline, Bowring says it is possible that a single, catastrophic pulse of magmatic activity triggered an almost instantaneous collapse of all global ecosystems. 
 
 To confirm whether the Siberian Traps are indeed the extinction's smoking gun, Burgess and Bowring plan to determine an equally precise timeline for the Siberian Traps eruptions, and will compare it to the new extinction timeline to see where the two events overlap. The researchers will investigate additional areas in China to see if the duration of the extinction can be even more precisely determined. 
 
 "We've refined our approach, and now we have higher accuracy and precision," Bowring says. "You can think of it as slowly spiraling in toward the truth." 
 
 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. www.pnas.org/cgi/doi/10.1073/pnas.1317692111 
 

– 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.