Massive, Ancient Supervolcanoes May Have Killed Half of Earth's Species
About 200 million years ago, a planet-wide catastrophe erupted, wiping out nearly all living species and paving the way for the rise of the dinosaurs. So what was the culprit? Massive, volcanic eruptions may have exploded across the Earth, releasing gases and causing the climate change that led to the End-Triassic Extinction.
The study, published in the journal Science, reveals that a set of major eruptions that spanned from New Jersey to Morocco occurred very close to the time of the mass extinction. The eruptions themselves began when the land on Earth was part of Pangaea, a giant supercontinent that existed before the landmasses broke apart. The volcanic activity lasted for more than 600,000 years and created a massive rift that became the Atlantic Ocean.
So how did the researchers come to their conclusions? They studied the ancient lava from these flows in Nova Scotia, Morocco and New Jersey. The scientists found that the oldest eruptions occurred in Morocco, followed by ones in Nova Scotia about 3,000 years later and lastly by ones in New Jersey which occurred another 10,000 years after that.
The researchers didn't examine the lava, though. They also noted that animal and plant remains from the Triassic era could be found buried beneath the lava, but not above the layer of the lava flowers. This suggested that the eruptions wiped out those species, causing mass extinctions.
In order to determine the age of the lava, the team examined their mineral content. In particular, the scientists measured the ratio of uranium to lead in the lava rock in order to find out when they occurred. In the end, they were able to determine the age of the fossil-containing sediments to within 20,000 years.
While some individuals during these eruptions may have died due to the lava flows, the real killer would have been the gases released from the volcanoes. The eruptions would have vented sulfates that reflected sunlight back into space, cooling the planet. Yet at the same time, the volcanoes would have released carbon dioxide and other gases. This would have caused a serious amount of global warming. Unable to survive this shift in climate, many species would have died.
A similar phenomenon is happening in the present day. Greenhouse gases continue to mount, warming the planet. The study not only shows what happened in the past, but could offer insight as to what could happen in the future.