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Eruption of Toba (74,000 BC) and humans in India

The eruption of Mount Toba, in what is now Indonesia, was the largest volcanic event of the last two million years. Mount Toba spewed as much as 3,000 cubic kilometers of magma, rained sulfuric acid down as far away as Greenland, and sent the world into a volcanic winter followed by a severe ice age.
As described here, the 'Toba catastrophe theory' claims that the Toba eruption is linked to a genetic bottleneck in human evolution about 50,000 years ago, which may have resulted from a severe reduction in the size of the total (world-wide) human population due to the effects of the eruption on the global climate. According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to just 3,000–10,000 surviving individuals.

At a more local level, the eruption showered all of India with levels of of volcanic ash that could reach two meters in height and which acts as a marker of age in Earth's strata today.

Anthropologist Michael Petraglia and his colleagues unearthed stone tool assemblages from above and below the Toba ash deposit in India's Jwalapuram Valley[1].
Because these stone tools were found both above and below a layer of ash left behind by a volcanic supereruption 74,000 years ago, the discovery hints that humans in the region survived the blast's devastating effects.

The tools the team found resemble those made by modern humans in Africa, suggesting that the Indian ones could have been made by humans too, Petraglia said.

"The fact that we have this ash is just icing on the cake, because it tells us that if it's modern humans, then they were able to persist through a major eruptive event," he said. "But they would have had a very, very difficult time."

[1] Petraglia et al: Middle Paleolithic assemblages from the Indian subcontinent before and after the Toba super-eruption in Science - 2007

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