HUMANS AND THE TOBA SUPER-ERUPTION 74,000 YEARS AGO: BEFORE AND AFTER THE ‘BIG BANG’
The Toba super-volcano has erupted explosively a number of times over the past 1.2 million years. By far the largest and most destructive of these occurred around 74,000 years ago, and it is this ‘Youngest Toba Tuff’ or YTT eruption that forms the focus of this research project. At least 2800 cubic kilometres of volcanic material was ejected during this super-eruption, dwarfing historical eruptions such as Krakatoa and Pinatubo.
The YTT explosion instantly destroyed all life in its immediate area, with intensely hot flows comprised of billions of tonnes of ash and rock, accompanied by a deafening noise and powerful tsunamis. It also sent hundreds of cubic kilometers of ash and gases high into the atmosphere, even as the volcano itself collapsed inwards to form a huge sunken caldera (now Lake Toba). The gases, including sulfur, circled the globe on air currents, while the ash spread out to the north and west fanned by prevailing winds. When the ash began to fall, it covered the Indian subcontinent and rained down into oceans from the Arabian Sea in the west to the South China Sea in the east (the figure above shows all the locations from which YTT desposits have been recovered to date). Gradually the earth cooled as the sun’s heat was reflected by the suspended gases, affecting rainfall and climates across the globe. Around this time the earth slipped rapidly into a dramatically cold portion of the ice ages, and while this was underway before Toba’s eruption, the super-volcano undoubtedly had an important influence.
HUMANS AND THE TOBA SUPER-ERUPTION 74,000 YEARS AGO: BEFORE AND AFTER THE ‘BIG BANG’
The Toba super-volcano has erupted explosively a number of times over the past 1.2 million years. By far the largest and most destructive of these occurred around 74,000 years ago, and it is this ‘Youngest Toba Tuff’ or YTT eruption that forms the focus of this research project. At least 2800 cubic kilometres of volcanic material was ejected during this super-eruption, dwarfing historical eruptions such as Krakatoa and Pinatubo.
The YTT explosion instantly destroyed all life in its immediate area, with intensely hot flows comprised of billions of tonnes of ash and rock, accompanied by a deafening noise and powerful tsunamis. It also sent hundreds of cubic kilometers of ash and gases high into the atmosphere, even as the volcano itself collapsed inwards to form a huge sunken caldera (now Lake Toba). The gases, including sulfur, circled the globe on air currents, while the ash spread out to the north and west fanned by prevailing winds. When the ash began to fall, it covered the Indian subcontinent and rained down into oceans from the Arabian Sea in the west to the South China Sea in the east (the figure above shows all the locations from which YTT desposits have been recovered to date). Gradually the earth cooled as the sun’s heat was reflected by the suspended gases, affecting rainfall and climates across the globe. Around this time the earth slipped rapidly into a dramatically cold portion of the ice ages, and while this was underway before Toba’s eruption, the super-volcano undoubtedly had an important influence.
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