字幕列表 影片播放 列印英文字幕 Around 252 million years ago more than 96 percent of marine species and 70 percent of land species disappeared in a geological instant. This event the so-called end-Permian mass extinction or more commonly known as, "The Great Dying" remains the most severe extinction event in Earth's history, but its direct cause has remained a mystery. Scientists suspect massive volcanic activity in an area of Russia called The Siberian Traps may have had a role in the Great Dying by raising the air and sea temperatures and releasing toxic amounts of greenhouse gases into the atmosphere of a very short period of time. However, until now, scientists could not pinpoint when exactly the mass extinction and eruptions happened in relation to each other. MIT researchers have now determined the Siberian Traps erupted at the right time and for the right duration to have been a likely trigger for the end-Permian extinction. By determining the age of rocks in the region the team came up with an exact timeline for the start and end of the eruptions. They found that the Siberian Traps began to erupt around 300 thousand years before the start of the extinction. These initial eruptions were followed by massive outpourings of lava covering a region as large as the United States. This area likely kept erupting in fits and starts finally petering out about 500 thousand years after the extinction's end. While the Siberian Traps has long been a suspected cause of the end-Permian extinction the team says its new timeline is in essence a smoking gun, placing the eruptions in the right place and time to have been the extinction's main trigger. Next, the team hopes to determine the exact tempo of eruptions, to perhaps identify a tipping point int he planet's climate leading up to the mass extinction.