Study: Humans in South Africa thrived during Toba super-volcanic eruption

March 12 (UPI) -- The Toba super-volcanic eruption that occurred 74,000 years ago significantly altered Earth's atmosphere and ecosystems around the planet, yielding hardship for most species, including humans.

But new research suggests that hunter-gatherers living on the coast of Southern Africa thrived in the wake of the massive eruption.

When Mount Toba, located in Indonesia, erupted some 74,000 years ago, the volcano spewed rock, gas and tiny glass fragments called cryptotephra into the atmosphere. These hook-shaped glass particles, identifiable under a microscope, spread across the globe.

While analyzing sediment from an archaeological site called Pinnacle Point near the town of Mossel Bay, South Africa, scientists found a shard of Toba glass. When formed, cryptotephra trap a chemical signature unique to the volcano they were spewed from.

Researchers identified the fingerprint of the Toba eruption in glass shards found at two different archaeological sites in Southern Africa, suggesting human populations continued to occupy the region in the decades following the eruption.

"Many previous studies have tried to test the hypothesis that Toba devastated human populations," paleoscientist Curtis W. Marean, head of the Pinnacle Point excavations, said in a news release. "But they have failed because they have been unable to present definitive evidence linking a human occupation to the exact moment of the event."

Marean and his colleagues used a laser-measurement device to precisely record the positioning of every sediment sample and artifact recovered from the dig site. Researchers then used the data to build 3D models and the site.

"These models tell us a lot about how people lived at the site and how their activities changed through time," said Erich Fisher, associate research scientist at Arizona State University's Institute of Human Origins. "What we found was that during and after the time of the Toba eruption people lived at the site continuously, and there was no evidence that it impacted their daily lives."

Scientists were able to confirm the age of the Toba shards by using optically stimulated luminescence, which measures how long ago a sediment layer was exposed to light. Researchers published the breakthrough discovery in the journal Nature.