Earth Was Hit By A Massive Meteorite 3.26 Billion Years Ago, And The Impact May Have Helped Early Life Flourish By Releasing Vital Nutrients For Microbes
A massive meteorite that struck Earth early on in its history wreaked havoc on the planet, but the impact may have allowed life to flourish.
At the time, microbial life was the only type of life in existence. An analysis of the remnants of the 3.26 billion-year-old impact revealed that microbial life may have benefited from a meteorite strike.
The meteorite in question was 50 to 200 times larger than the one that killed all the non-avian dinosaurs. The meteorite, along with a tsunami that occurred as a result of the impact, unleashed nutrients into the atmosphere that were vital to microbes.
“Not only do we find that life has resilience because we still find evidence for life after the impact; we actually think there were changes in the environment that were really great for life,” said Nadja Drabon, the lead author of the study and an assistant professor of planetary sciences at Harvard University.
Drabon and colleagues looked into a meteorite impact that took place during the Archean era (4 billion to 2.5 billion years ago) in what is now South Africa. The region was a shallow sea environment back then.
In the rock layers, the researchers could see spherules, which are tiny, glass-like orbs that form when silica-containing rock melts due to a meteorite impact. They also observed conglomerates, rocks made of other chunks of rock.
The conglomerates are proof that a worldwide tsunami destroyed the seafloor and mushed the debris into clumps. Remnants of the actual meteorite were detected in the chemistry of the rock layers.
The rock was a type of space rock known as a carbonaceous chondrite. It would’ve measured between 23 and 36 miles in diameter.
The South African site was far away from where the meteorite collided with the Earth, but it still experienced the consequences. The meteorite caused a tsunami that swept across the entire globe and generated enough dust to block the sun.
Tryfonov – stock.adobe.com – illustrative purposes only – pictured above is earth in a view from outer space
Evidence of evaporated minerals also shows that the impact heated the atmosphere enough for the upper layers of the ocean to reach the boiling point. Any life on land or in shallow water would’ve faced the ultimate chaos.
But within a few years or decades of the impact, life began to return to normal, or even better than normal.
After the impact, more essential nutrients were available. For one, there was an increase in phosphorus, which was probably rare in oceans 3.26 billion years ago.
Today, phosphorus makes its way into the oceans due to erosion of continental rocks. But during the Archean era, water covered most of the Earth, and there weren’t as many volcanic islands or small continents where rocks could be found.
The size of the meteorite meant that it would’ve contained hundreds of gigatons of phosphorus. Another element made abundant by the meteorite strike was iron. The metal was common in the deep oceans but not in shallower waters.
The tsunami triggered by the collision ended up mixing the oceans and bringing more iron to the surface. Red rocks in the layer illustrate this environmental change.
The study explains how life began to flourish on a young Earth. It also shows how every meteorite’s impact has both negative and positive effects.
Meteorites might cause destruction and ruin, but they can also pave the way for new life to develop.
The details of the findings were published in PNAS.
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