At least one group of early humans managed to survive the Mount Toba supervolcano in Sumatra 74,000 years ago.
In fact a study featuring the work of University of Wollongong scientist, Professor Zenobia Jacobs, found that not only did the population on the South African coast survive one of Earth’s most explosive volcanic events, it managed to flourish through the period of the eruption and its after effects.
Prof Jacobs and other scientists studied two archaeological sites on the southern coast of South Africa – Pinnacle Point and Vleesbaai – that have been dated to around the time of the Toba eruption.
They found evidence that people occupied the sites continuously from 90,000 to 50,000 years ago.
The study published online in Nature this week, also has important implications for archaeological dating techniques.
Prof Jacobs from UOW’s School of Earth and Environmental Sciences and the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, led the dating of the site.
She said the fact the paper was looking very specifically at how the Toba eruption affected the people living at the time meant the accuracy of the dating became paramount.
“When you pinpoint something and try to answer a very specific question, like did the Toba eruption have an effect on populations, then accuracy becomes really important because you try to tie it to something that is very accurately dated,” Prof Jacobs said.
“We started excavating in 2006 and every year, as the archaeologists excavated away more of the layers, I would go back into the field and take a sample from almost every individual layer that we could identify. We’d make sure we knew what the relationship was between the layers, the archaeology, and the sand that we extracted.
“We did that at night because the OSL signal is sensitive to sunlight – we’d go out at night with red torches and extract some sediment with a spoon or a small trowel and put them into a black plastic bag to protect them from light. Then we’d bring it back to the lab and analyse the data.”
The paper concludes by raising the question of whether “the modern human population on the south coast of South Africa was the sole surviving population through a decade or more of volcanic winter, or whether populations elsewhere in Africa thrived through the [Toba] event”.
Prof Jacobs believes it is likely that glass shards from Toba will be discovered at other archaeological sites in Africa rounding out our understanding of how the event affected our ancient ancestors.