Roughly 250 million years ago, nearly 95% of all life was obliterated; wiped away by a series of events that occurred after a massive volcanic eruption. But Earth has been through five disastrous mass extinctions since the existence of life. The most famous mass extinction is the asteroid impact that wiped out the dinosaurs, which paved the road for humans to reign the globe. But what people don’t realize is that a much larger mass extinction occurred on Earth before the dinosaurs, and this extinction was the worst to ever occur on the Earth. But it is about the evidence surrounding how this happened that is startling.
Paleontologist Roger Smith has been studying the reasoning of the extinction in the Karoo Basin in South Africa. Today it is a barren landscape, inhabitable for life. It’s hard to imagine life once thrived there. He looked for evidence in the rock formations and noticed that a rock with a carbon date of 300 million years showed evidence of an abundance of life and noticed that above that rock formation was a rock with a carbon date around the time of the mass extinction, and it showed the absence of life including plants and soil. Something had to have happened. In the early 1990s, researchers found startling evidence thousands of miles away in Siberia.
Beneath the frozen Siberian tundra was thousands of miles of lava. It is known as the Siberian traps, which are recorded to be the most massive and destructive volcanic eruption in the history Earth; even bigger than Yellowstone eruptions. The scale of the eruption can be difficult to comprehend. Roughly 250,000 cubic miles of lava were spewed out over almost a million years time. But the Siberian traps were on the other side of the world of the Kaboo Basin.
Smith goes on to explain the Laki eruption of 1783. This eruption spilled over 200 square miles of lava over Iceland for a period of 8 months. No one died as a result of the lava flow, but the eruption caused widespread chaos over Europe and even the newly formed America. The Laki eruption spewed out 122 million tons of sulphur compounds. “These combined with water vapour in the stratosphere to form tiny droplet clouds of sulphur dioxide. Acting like mirrors, the light-coloured droplets reflected sunlight back into space. Deprived of the sun’s heat and light, the entire northern hemisphere cooled. Temperatures dropped to 7ºC below the average in Iceland and in the western United States they dropped by 5ºC. The sulphur dioxide eventually fell to the Earth as acid rain which poisoned the struggling crops and eroded the soil. As a result, 50% of Iceland’s cattle perished and 20% of its population starved.”
To put this in perspective, the Siberian traps eruption was 250,000 larger than the Laki eruption. The Laki eruption only covered an area a third the size of London whereas the Siberian traps covered an area as large as the United States or Russia. The effects of the Laki eruption need to be amplified by 2.5 million times if it is even going to be similar to the eruption of the Siberian traps. As a result of this, the temperature on Earth was largely increased.
All information was acquired from Naomi Miles – http://www.firstscience.com/home/articles/origins/the-biggest-extinction-on-earth-page-1-1_18172.html