Massive Eruption 225 Million Years Ago Led to Mass Extinction

Geologists and other experts from the University of Leeds have recently demonstrated the existence of another global extinction event, other than the five ones already documented. They discovered traces of a giant volcanic eruption that led to worldwide annihilation some 260 million years ago, and took place in the Emeishan province of what is now southwest China. According to preliminary estimates, the massive eruption unleashed no less than half a million cubic kilometers of lava, which covered an area about five times the size of Wales, or roughly 104,000 square kilometers (40,110 square miles).

While the initial, land-based impact was fairly reduced, the effects of the devastation were more widespread in the world's oceans, where a large percentage of all marine species died because of it. In a study published in the Friday edition of the journal Science, the University of Leeds researchers were able to directly link the exact time of the eruption (which has been accurately pinpointed) to a widespread extinction event on the planet.

 

 “When fast flowing, low viscosity magma meets shallow sea it's like throwing water into a chip pan – there's spectacular explosion producing gigantic clouds of steam,” explained the lead author of the paper, University of Leeds paleontologist professor Paul Wignall. “The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe, a correlation that has often been controversial.”

 

Because the volcanic eruption happened in shallow waters, it was fairly easy for the scientists to discover the layer of rock corresponding to this time frame. The black volcanic rock layer was sandwiched between two sedimentation layers, in which traces of marine life fossils were clearly visible. However, in the volcanic layer, there were close to no fossils, and the layer immediately above it showed a much lower diversity of life than the one immediately beneath.

 

Another dangerous byproduct of the eruption was an unimaginably vast amount of sulfur dioxide, which was released into the atmosphere when the molten rock flowing off the volcano hit the shallow waters of the sea nearby. Huge clouds of steam formed, and they were all laden with the dangerous chemicals. Prevailing winds could have carried these clouds all around the globe, suffocating larger animals, and forcing smaller organisms into hiding.

 

Additionally, the large concentration of sulfur in the atmosphere, spread across the planet, would have triggered a significant wave of global cooling, and would have also created abundant amounts of acid rain that would have destroyed vegetation and severely disrupted the ecosystem.