Huge meteorite that hit Earth 3bn years ago 'sparked biggest tsunami in history' but 'may have helped life flourish'
22 October 2024, 07:47
A massive meteorite that hit the Earth three billion years ago may have caused ancient life to flourish.
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The S2 meteorite, which was the size of Mount Everest, smashed into Earth when it was still relatively young.
A meteorite striking the planet is usually disastrous, causing seas to boil and huge blankets of dust to rise up, blocking out the sun.
But S2, which had a diameter of between 37 and 58 kilometres (23-36 miles), may have improved conditions for some life forms.
Nadja Drabon, an early-Earth geologist and assistant professor in the department of Earth and planetary sciences at the University of Harvard, said: "We think of impact events as being disastrous for life.
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"But what this study is highlighting is that these impacts would have had benefits to life, especially early on ... these impacts might have actually allowed life to flourish."
S2 was around 200 times larger than the one that killed the dinosaurs 65 million years ago, scientists think.
When it hit, it triggered the largest tsunami in history, which mixed up the oceans and pushed debris from the land into areas by coasts.
The heat caused by the impact boiled off the upper layer of the oceans, heated up the atmosphere and created a thick layer of dust.
But bacterial life bounced back quickly, and with this came sharp spikes in populations of single-celled organisms that feed off the elements phosphorus and iron.
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The scientists suggest iron was likely stirred up from the deep ocean into shallow waters by the tsunami, and phosphorus was brought to the planet by the meteorite itself and from an increase of erosion on land.
Prof Drabon's findings indicate that iron-metabolising bacteria would therefore have flourished in the immediate aftermath of the impact.
Experts suggest this shift towards iron-favoring bacteria is a key puzzle piece depicting early life on Earth.
Evidence of the impact is found in the Barberton Greenstone belt of South Africa today.
Dr Drabon said: "Picture yourself standing off the coast of Cape Cod, in a shelf of shallow water.
"It's a low-energy environment, without strong currents. Then all of a sudden, you have a giant tsunami, sweeping by and ripping up the sea floor."
The findings are published in the Proceedings of the National Academy of Sciences journal.
The Earth is around 4.5 billion years old, meaning the planet formed around 1.2 billion years before S2's impact.
