WASHINGTON — A meteorite that struck Earth 66 million years ago at the end of the Cretaceous Period caused a global disaster that led to the extinction of dinosaurs and many other species. However, this event was not the largest meteorite to hit our planet. A much larger meteorite, estimated to be 200 times the size, impacted Earth 3.26 billion years ago, resulting in widespread devastation on an even greater scale.

New research suggests that this earlier disaster may have had positive effects on the early evolution of life, acting as "a giant fertilizer bomb" for the bacteria and archaea that dominated the planet at the time by supplying essential nutrients like phosphorus and iron.

Researchers studied ancient rocks from the Barberton Greenstone Belt in northeastern South Africa to assess the impact of this meteorite. They discovered numerous indicators of life’s recovery, including geochemical signatures from preserved organic materials and fossils of marine bacterial mats.

"Life not only recovered quickly once conditions normalized within a few years to decades, but it actually thrived," said Harvard geologist Nadja Drabon, the study's lead author, whose findings were published in the Proceedings of the National Academy of Sciences.

During the Paleoarchean Era when this event occurred, Earth was very different, with more frequent and larger meteorite impacts. The planet resembled a water world, featuring few volcanoes and little dry land, with virtually no oxygen in the atmosphere or oceans and no eukaryotic cells.

The meteorite, a carbonaceous chondrite rich in carbon and phosphorus, was about 23-36 miles (37-58 km) in diameter, making it 50-200 times the mass of the asteroid responsible for the dinosaurs' extinction.

"The impact would have been immediate and violent, vaporizing the impactor and the sediment it struck. A cloud of rock vapor and dust would have enveloped the globe, darkening the sky within hours," Drabon explained. "The impact likely occurred in the ocean, generating a tsunami that would have devastated coastlines and disturbed the sea floor. Additionally, much of the impact's energy would have turned into heat, causing the upper ocean layers to begin boiling."

It would have taken years to decades for the dust to settle and for the atmosphere to cool enough for water vapor to condense back into the oceans. Microbes dependent on sunlight and those in shallow waters would have been significantly affected.

However, the meteorite would have introduced a substantial amount of phosphorus, a crucial nutrient for microbes, essential for molecules that store and transmit genetic information. The tsunami would have also mixed iron-rich deep waters into shallower regions, creating favorable conditions for various microbes that utilize iron as an energy source.

"Consider these impacts as massive fertilizer bombs," Drabon remarked. While meteorite impacts are typically viewed as catastrophic—like the Chicxulub impact that wiped out the dinosaurs and 60-80% of Earth's species—3.2 billion years ago, life was much simpler.

"Microorganisms are relatively simple, adaptable, and reproduce rapidly," Drabon noted.

Evidence of the impact included chemical traces of the meteorite, small spherical structures formed from melted rock, and seabed debris mixed with other materials stirred up by the tsunami in sedimentary rock.

"Early life proved resilient in the face of such a significant impact," Drabon concluded.

Disclaimer: This image is taken from Nadja Drabon via Reuters