About 445 million years ago, about 85% of the marine life on Earth then disappeared after a geological event. This is considered a mass extinction in the Ordovician period.
According to the New York Times, this extinction event has long been considered a major mystery in Earth's history. Scientists have long debated its cause, as other mass extinction events have all given clear explanations.
" The extinction event in the Ordovician period has always been something strange," said Stephen Grasby of the Canadian Geological Survey.
The Ordovician period is the second of the six centuries of Paleozoic. It takes place after the Cambrian period and right after it is the Silurian period.
Now Grasby and his partner David Bond, from the University of Hull, UK, think they have found a solution to this mysterious event, and published their conclusions last month in the journal Geology. .
According to them, volcanic eruptions that took place all over the Earth released enough carbon dioxide to heat the planet and trigger two waves of extinction that occurred on Earth only a million years apart.
If this is true, then the extinction event in the Ordovician period is similar to the rest of the extinction events because they are all caused by global warming.
Describe images of ocean life in the Ordovician period, between 485.4 and 443.8 million years ago. (Photo: New York Times).
Bond and Grasby made their assumptions after collecting Ordovician rocks from a small stream in southern Scotland. They are then transported to Vancouver, Canada for research. They found that when exposed to heat, the stones released large amounts of mercury - a sign that they came from a volcanic eruption.
The rocks also emit molybdenum and uranium - localization information suggests that the oceans have no oxygen. The most plausible reason is that the Earth is heating up rapidly, leaving the oceans free of oxygen, and suffocating marine life.
"Imagine it like a bottle of Coca-cola. If you store it in the fridge it will still have gas, but if you leave it on a table in the sun, the gas will quickly come out of the liquid. And you only have one bottle of non-carbonated Coca , " Mr. Bond explained.
According to the two scientists, it is likely that during this period, the Earth's crust began to crack, and lava flows erupted from everywhere. This process causes large amounts of carbon dioxide and mercury to be released, leading to rapid global warming.
If this hypothesis holds true, the first mass extinction event will have a similar origin to other events. For some scientists, this will give them more incentive to study these extinction events - which will give us a better insight into the impact of humans today, because we also release carbon dioxide and other greenhouse gases into the atmosphere.
Although unbelievable, according to Seth Finnegan, a paleontologist at the University of California, Berkeley, humans are emitting greenhouse gases at or above the extinction events that have occurred on Earth. .