The appearance of oxygen on Earth is associated with asteroids
At the beginning of its history, the Earth has repeatedly experienced powerful asteroid “rains”. A new study has shown that the scale of these space bombings could be 10 times larger than previously thought, according to the Goldschmidt Conference.
Scientists from the US Southwestern Research Institute have come to the conclusion that in the Archean era (2.5 – 3.5 billion years ago), the Earth was subjected to asteroid strikes every 15 million years. Some of them were up to 10 kilometers in diameter.
Such cataclysms should have greatly affected the geochemistry of the Earth and the development of life on the planet. It is very difficult to study them, since the oldest impact craters have already disappeared due to weathering and plate tectonics. But traces of asteroids can still be found.
Spherules are preserved in rocks several billion years old. These are vitreous particles that form from the rock melted by the explosion. The more spherules are present in a particular cultural layer, the more powerful the catastrophe was.
Scientists, having analyzed the content of ancient sediments, found that modern science underestimates the scale of cosmic impacts.
“It is likely that these events have radically changed the evolution of the earth's surface and atmosphere,” – noted the authors of the scientific work.
So, the impacts of asteroids should have been reflected in the level of atmospheric oxygen. During the period of intense exposure, he had to actively fluctuate.
It is known that the saturation of the earth's atmosphere with oxygen occurred about 2.5 billion years ago. But even before that, there were some “bursts” of this gas. Previously, scientists believed that they are associated with the processes taking place in the bowels. But, as new data showed, the outbursts could also be caused by an influence from space.
“Given the importance of oxygen for the development of the Earth and for the development of life, its possible connection with asteroids is intriguing and deserves further study. This is the next stage of our work, ”the scientists noted.
Earlier it was reported that traces of a large meteorite fall were found in Antarctica. He collided with the Earth over 400,000 years ago.
