Supervolcano Eruption Sheds Light on Human Migration from Africa

Contrary to previous assumptions regarding the migration of modern humans out of Africa, it is suggested that some movement may have been prompted not by ‘green corridors,’ but by hardship or deprivation.

A recent analysis involving volcanic glass discovered in Ethiopia suggests that humans inhabited regions experiencing potential drought conditions in the Horn of Africa around 74,000 years ago. This environmental challenge likely compelled them to adapt and potentially migrate in search of better resources.

The Genesis of Human Migration Trails

By following seasonal rivers and waterholes, where food was more abundant, humans may have created what scientists refer to as ‘blue highways,’ facilitating their dispersal out of Africa and into other regions.

According to anthropologist John Kappelman from the University of Texas at Austin, who led the research, “As people depleted food in and around a given dry season waterhole, they were likely forced to move to new waterholes. Seasonal rivers thus functioned as ‘pumps’ that siphoned populations out along the channels from one waterhole to another, potentially driving the most recent out-of-Africa dispersal.”

Throughout prehistory, both humans and their ancestors have undertaken multiple migrations out of Africa, often driven by changes in climate conditions. However, determining the specific timing and reasons behind large-scale human migrations out of Africa can be a complex endeavor.

The ‘green corridor’ theory posits that human migration expanded in tandem with the availability of food resources. However, Kappelman and his colleagues aimed to explore an alternative catalyst for the most recent and widespread migration, occurring less than 100,000 years ago.

Unveiling Ancient Life

Their study centered on the Shinfa-Metema 1 archaeological site in present-day northwestern Ethiopia, aiming to understand the lifestyle of its inhabitants. Among the findings were stone tools, animal bones indicative of their diet, remnants of cooking fires, and minute fragments of volcanic glass, known as cryptotephra, with chemical signatures matching those of the Toba eruption.

Archaeologist Curtis Marean from Arizona State University highlights a groundbreaking implication of this study, stating, “With the new cryptotephra methods developed for our previous research in South Africa, and now utilized here in Ethiopia, we can establish correlations between sites across Africa, and potentially globally, with a resolution of several weeks of time.”

Microscopic Witnesses

Cryptotephra, although smaller than the width of a human hair, provide valuable insights into human history. They can indicate the extent of an eruption’s impact, as well as aid scientists in establishing precise dates for archaeological findings. Previous studies have demonstrated the presence of ash from eruptions in various parts of Africa.

In the case of Shinfa-Metema 1, researchers compiled a diverse array of evidence. Bones and teeth provided insights into the diet of the site’s inhabitants, evidenced by cut marks from hunting and butchery. Their diet primarily consisted of mammals such as monkeys and antelopes; however, as these resources became scarce, they increasingly relied on fish.

Fascinatingly, certain stone artifacts discovered at the site resemble arrowheads. According to the researchers, this constitutes the earliest known evidence of archery.

The researchers also conducted oxygen isotope analysis on mammal teeth and fragments of ostrich eggshells recovered from the site. The resulting ratios indicated a period of significant aridity.

While the individuals at the Shinfa-Metema 1 site likely weren’t part of the migrating population, they demonstrated a notable level of adaptability during challenging circumstances. This suggests that humans were adept at adjusting to changing conditions, even if it meant seeking out more favorable environments.

“This study corroborates findings from Pinnacle Point in South Africa,” Marean notes. “The Toba eruption may have altered the African environment, but humans were able to adapt and persevere.”

Read the original article on: Science Alert

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