An ancient volcanic eruption almost destroyed humanity: what happened

Some scientists suspected that the volcanic winter that resulted from the eruption was a shift large enough to wipe out most early humans, due to genetic evidence suggesting a sharp decline in the human population.

But now a cutting-edge study of an archaeological site in northwestern Ethiopia once inhabited by early modern humans has added to the growing body of evidence that the event may not have been so apocalyptic, CNN reports.

Instead, the new study found that people at the site, known as Shinfa Metema 1, adapted to the dry conditions caused by the volcanic eruption in a way that may have contributed to the major human migration from Africa to the rest of the world.

Microscopic fragments of volcanic glass found alongside stone tools and animal remains in the same layer of sediment at the Shinfa-Metema site 1, near the Shinfa River in Ethiopia, show that people occupied the site before and after the eruption of a volcano more than 4,000 miles away. miles.

“These fragments are smaller than the diameter of a human hair. Even so tiny, they are still large enough for chemistry and trace element analysis,” says John Kappelman, professor of anthropology and geological sciences at the University of Texas at Austin and lead author of the study, which was published recently in the journal Nature.

By piecing together evidence from fossils and artifacts found at the site, along with geological and molecular analysis, the team began to understand how the people living there moved forward despite likely climate change caused by the volcanic cataclysm.

To understand the climate at the time of the eruption, Kappelman and his colleagues analyzed oxygen and carbon isotopes, variations of the same element, from ostrich egg shells and fossilized mammal teeth. This work shed light on water consumption and showed that the animals ate plants that were more likely to grow in drier conditions.

“Isotopes are found in solid tissues. So for mammals, we look at their teeth, their tooth enamel, but we also find them in ostrich eggshells,” Kappelman said.

Analysis of the site’s flora and fauna also revealed an abundance of fish remains from the eruption. The find may not be surprising given how close the site was to the river, but the fish are rare at other Stone Age sites from the same period, the study notes.

“People started increasing the percentage of fish in their diet when Mount Toba erupted. They are catching and processing almost four times as much fish as before the eruption, he said. “We think the reason for this is that if Toba actually creates more aridity, that means the rainy season will be shorter, which means the dry season will be longer.”

The team theorized that a drier climate counterintuitively explained the increased reliance on fish: As the river shrank, fish became trapped in holes or smaller streams that were easier for hunters to target.

The fish-rich bodies of water may have potentially created what the team described as a “blue corridor,” along which early humans moved north from Africa when they ran out of fish. This theory contradicts most other models, which suggest that the bulk of human migration out of Africa took place along “green corridors” during wet periods.

“This is research. demonstrates the great plasticity of Homo sapiens populations and their ability to easily adapt to any type of environment, be it hyper-humid or hyper-arid, including during catastrophic events such as the hyper-explosion of the Toba volcano,” comments Ludovic Slimac, researcher at the French National Center for Scientific Research Research and the University of Toulouse.

The study authors were also able to study the geology of the ancient river bed, which suggested that it flowed slower and lower in this place than at present.

“We can do this just by looking at the cobblestones,” Kappelman said. – A very energetic river can move larger boulders and rocks than a river that is not as energetic. The cobbles we find for the ancestral river are smaller than the river today.”

The researchers also discovered the remains of several small triangular points that, surprisingly, are among the earliest examples of the use of archery and provide clues that the inhabitants of the site may have used bows and arrows to hunt fish and other large game. .

Ludovic Slimak, who studied similar objects discovered in France that date back 50,000 years, agreed with the new study’s assessment of the artifacts.

“The authors also identify very clear signs pointing to the existence of archery here 74,000 years ago,” Slimak said. “Thus, there is every reason … to consider these ancient Homo sapiens as bearers of already highly developed technologies, largely freed from natural and climatic restrictions, which is a decisive factor for understanding their subsequent migrations across all continents and under all latitudes.”

Ancient human species likely left Africa multiple times, but archaeologists and geneticists generally agree that the most significant expansion of Homo sapiens, our own species, which ultimately led to modern humans living in all corners of the globe, occurred around 70,000-50,000 years ago.

The new study offers another potential scenario for how this dispersal occurred, without ruling out previous theories, says Chris Stringer, professor and director of research in human evolution at the Natural History Museum in London.

“I’m sure each of these proposals will be controversial among the relevant experts, but I think the authors have made plausible (though not conclusive) arguments for each scenario they propose,” Stringer comments.