"Their technology was stone and wood and bone and leather," he continued, "but relative to the rest of the world, they were ahead of the game with a new, advanced projectile technology called microlithic technology."
The innovation enabled the early South Africans to create composite tool components as part of advanced weapons that could be thrown over greater distances.
Human life therefore seemed to be thriving at these coastal South African locations when Mount Toba erupted.
It is hard to imagine what the people witnessed just after the explosive event.
"The length and severity of the Toba volcanic winter are hotly debated," Marean said. "This can only be answered with climate modeling and high-resolution climate and environmental records."
What is now known is that the early modern humans living at Vleesbaai and Pinnacle Point prospered despite the natural disaster that likely had a global impact. The determination adds important insight to the Toba catastrophe theory.
This theory goes back to the early 1990s, when biologist Michael Rampino of New York University, volcanologist Stephen Self of the University of Hawaii at Manoa, and science journalist Ann Gibbons all posited that the Mount Toba eruption could have caused a sharp reduction in the human population, known as a population bottleneck. The theory has since been developed by Stanley Ambrose of the University of Illinois at Urbana-Champaign.
Marean said that he found Ambrose's work on the subject "to be exciting and worth investigating ... Then my colleague Panagiotis Karkanas saw a shard under his microscope and we were off on the chase."
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Lead author Eugene Smith of the University of Nevada Las Vegas told Seeker that analysis of the cryptotephra "took a lot of very careful work over a period of nearly two years." The analysis occurred not only at his lab, but also at Guillaume Girard's lab at Michigan State University.
It is possible that the rock shelter sufficiently shielded the early South Africans from the potentially dangerous volcanic debris. If the volcanic winter extended to this region, it is even possible that this population was one of the few that survived nature's onslaught. The people could have survived the devastating time due to their distance from the eruption and the ample potable water and food sources at the coastline, the authors suggest.
As for what happened in Indonesia and surrounding areas, the evidence is unclear. Jacobs said, "There is currently no fossil remains of Denisovans or Neanderthals from Indonesia or anywhere in southeast Asia at any time." She added that Toba's debris has not been found on the Indonesian island of Flores, known to be inhabited by Homo floresiensis, aka the hobbit humans, so named because of their relatively diminutive size.
She explained that the massive Toba ash cloud did not blow to the east, but rather moved northeastwards. Significant amounts of the deposits have therefore been found in the South China Sea, as well as across India.
She added, however, that "it is hard to imagine that a volcanic eruption of that size did not have any effects on the tectonic plates running through Indonesia and triggered other smaller volcanoes that may have had variable effects."