On the island of Sumatra some 74,000 years ago, an erupting supervolcano wreaked havoc, sending up plumes of ash and debris that spread for thousands of miles and caused temperatures to plummet.
Genetic evidence shows that modern humans descend from a population that numbered only in the thousands when it ventured out of Africa some 60,000 years ago.
But to better understand what was happening in Africa, researchers needed to find archaeological sites interspersed with Toba ash.
Based on the evidence, the team argues that modern human populations on the South African coast thrived after the eruption, staying at the site for thousands of years and even developing innovations in their tools.
Marean and his colleagues suggest that the South African coast may have acted as a refuge—perhaps the refuge—for modern humans weathering the Toba eruption.