The huge asteroid which, according to prevailing theory, struck Earth 66 million years ago, at the end of the Cretaceous Period, causing a global catastrophe that doomed the dinosaurs and 80% of life on the planet paving the way for the dominance of mammals and, eventually, the emergence of man. A new study that is published in the journal PNAS reports that a meteorite much larger than the asteroid that wiped out the dinosaurs crashed onto early Earth and did just the opposite of helping life thrive on the planet.
According to the study, a meteorite with a diameter of 37 to 58 km, that is, 50 to 200 times greater in mass than the asteroid that exterminated the dinosaurs, fell to Earth around 3.26 billion years ago.
The researchers report that, apparently, such a collision caused enormous destruction on the planet, but was also beneficial for the evolution of life that appeared on the planet, as it served as a “giant fertilizer bomb for bacteria and other single-celled organisms.” organisms that dominated at that time.” According to the researchers, the fall of the meteorite provided unicellular organisms with the basic nutrients phosphorus and iron.
“Not only did life recover quickly when conditions returned to normal within a few years or decades, it also thrived,” said Nanja Drabon, a geologist at Harvard University who led the research team.
What happened
The meteorite was of a type called carbonaceous chondrite, rich in carbon and also containing phosphorus.
“The impact likely occurred in the ocean, causing a tsunami that swept the globe, destroying the sea floor and flooding coastlines. Ultimately, much of the energy from the impact would have been transferred to heat, meaning the atmosphere began to heat up so much that the upper layer of the oceans began to boil. It would likely take a few years or decades for the dust to settle and the atmosphere to cool enough for the water vapor to return to the ocean. Sunlight-dependent microbes and those living in shallow waters would have been decimated. But the meteorite would have provided a large amount of phosphorus, a microbial nutrient crucial to molecules central to the storage and transfer of genetic information. The tsunami would also have mixed iron-rich deep waters with shallower waters, creating an ideal environment for many types of microbes because iron provides them with an energy source. Think of these effects as giant fertilizer bombs,” says Drabon.
Naftemporiki.gr