Researchers have found that the end-Permian mass extinction that happened was faster and shorter than previously thought.
Around 252 million years ago, the largest mass extinction of animal life occurred on earth that wiped out over 96 percent of marine species and more than 70 percent of life on land. Many previous theories aimed to establish the cause of the extinction, including an asteroid impact, massive volcanic eruptions and disastrous environmental events. However, researchers say that understanding the exact cause of mass extinction needs better measurements of how long the extinction period lasted.
Researchers at the Massachusetts Institute of Technology (MIT) say that mass extinction occurred over 60,000 years. A more precise dating technique has been used to establish the new timescale and reveals that it happened more than 10 times faster than previously believed by scientists.
"We've got the extinction nailed in absolute time and duration," said 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."
Bowring, along with Seth Burgess (a graduate student) 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 reflects a mass outpour of carbon dioxide to the atmosphere. This change is likely to have led to widespread ocean acidification and an increase in sea temperatures by about 10 degrees Celsius that resulted in the extinction of sea life.
However, scientists are yet to determine the cause of the spike in carbon dioxide in the atmosphere. Previous studies among geologists and paleontologists indicate that long-lasting volcanic eruptions from the Siberian Traps, a region of Russia, resulted in a sudden increase of carbon dioxide. Burgess and Bowring are now trying to establish a timescale for the Permian period's volcanic eruptions that are supposed to have covered over 5 million cubic kilometers.
"It is clear that whatever triggered extinction must have acted very quickly," says Burgess, the lead author of a paper. "Fast enough to destabilize the biosphere before the majority of plant and animal life had time to adapt in an effort to survive."
In another study, which is based on an analysis of zircon crystals found in the geological formation in Meishan, China, researchers estimated that the mass extinction happened in less than 200,000 years. Researchers say that fossils discovered in this region may help them to better understand the secret of the mass extinction.
Researchers are now analyzing rock samples found in China with those from the Siberian Traps in Russia to understand and compare the eruptions' timelines.
