Excavations at Dhaba in northern India
© CHRISTINA NUEDORF
Archaeological excavations at Dhaba in northern India.
Humans survived one of the largest known volcanic events - the Mount Toba super-eruption in Sumatra, Indonesia, 74,000 years ago - new research shows.

Some have argued that the eruption caused an extended volcanic winter that disrupted human dispersal out of Africa and the colonisation of Australasia, although archaeological evidence has been limited.

Now an international study by researchers from Australia, Germany, India, the US and the UK, led by Chris Clarkson from Australia's University of Queensland, has found that human occupation of northern India spanned the Mount Toba eruption.

In a paper in the journal Nature Communications they describe a large collection of stone artefacts from archaeological excavations at Dhaba in the Middle Son River Valley which indicate that the area has been continuously occupied over the last 80,000 years.

Similarities between Levallois tool technology (stone tools created by flint knapping) at Dhaba and those found in Arabia between 100,000 and 47,000 years ago and in northern Australia 65,000 years ago also suggest linkage of these regions by an early modern human dispersal out of Africa, they say.

The study shows that around 48,000 years ago in Dhaba there was a shift to microlithic technology - the production of smaller stone tools, typically a few centimetres in length.

The new research further refutes suggestions that the super-eruption caused a six-year volcanic winter that resulted in a 1000-year cooling of the Earth's surface and the near extinction of our own species.

And Clarkson says archaeological evidence from other sites in Africa, India and Asia also supports the idea that the Toba eruption had minimal effects on humans and did not cause a population bottleneck.

"In fact, archaeological sites in southern Africa show human populations thrived following the Toba super-eruption," he says.

"Climate and vegetation records from Lake Malawi in East Africa likewise show no evidence for a volcanic winter at the time of the eruption."

Genetic studies similarly have not detected a clear population bottleneck around 74,000 years ago.

"In Sumatra, close to the eruption itself, colleagues found Homo sapiens teeth which dated back to 73,000-63,000 years ago," Clarkson says.

"This indicates Homo sapiens was living in Sumatra in a closed canopy rainforest environment soon after the eruption."