Saturday, February 27, 2010

Humans Arrived in India More 74,000 Years Ago and Survived the Toba Volcano Super Eruption


 Rock art in the Jurreru River valley
 Image Credit: Oxford University

Humans may have arrived in India as long ago as 100,00 years. A time when humans and Hobbits inhabited Southeast Asia. 

Newly discovered archaeological sites in southern and northern India have revealed how people lived before and after the colossal Toba volcanic eruption 74,000 years ago. The international, multidisciplinary research team, led by Oxford University in collaboration with Indian institutions, has uncovered what it calls ‘Pompeii-like excavations’ beneath the Toba ash.

The seven-year project examines the environment that humans lived in, their stone tools, as well as the plants and animal bones of the time. The team has concluded that many forms of life survived the super-eruption, contrary to other research which has suggested significant animal extinctions and genetic bottlenecks.

According to the team a potentially ground-breaking implication of the new work is that the species responsible for making the stone tools in India was Homo sapiens.  Stone tool analysis has revealed that the artefacts consist of cores and flakes, which are classified in India as Middle Palaeolithic and are similar to those made by modern humans in Africa.

 ‘Though we are still searching for human fossils to definitively prove the case, we are encouraged by the technological similarities. This suggests that human populations were present in India prior to 74,000 years ago, or about 15,000 years earlier than expected based on some genetic clocks,’ said project director Dr Michael Petraglia, Senior Research Fellow in the School of Archaeology at the University of Oxford.

An area of widespread speculation about the Toba super-eruption is that it nearly drove humanity to extinction. The fact that the Middle Palaeolithic tools of similar styles are found right before and after the Toba super-eruption, suggests that the people who survived the eruption were the same populations, using the same kinds of tools, says Dr Petraglia. The research agrees with evidence that other human ancestors, such as the Neanderthals in Europe and the small brained Hobbits in Southeastern Asia, continued to survive well after Toba.

Although some scholars have speculated that the Toba volcano led to severe and wholesale environmental destruction, the Oxford-led research in India suggests that a mosaic of ecological settings was present, and some areas experienced a relatively rapid recovery after the volcanic event. The team has not discovered much bone in Toba ash sites, but in the Billasurgam cave complex in Kurnool, Andhra Pradesh, the researchers have found deposits which they believe range from at least 100,000 years ago to the present. They contain a wealth of animal bones such as wild cattle, carnivores and monkeys. They have also identified plant materials in the Toba ash sites and caves, yielding important information about the impact of the Toba super eruption on the ecological settings.

Dr Petraglia said: ‘This exciting new information questions the idea that the Toba super-eruption caused a worldwide environmental catastrophe. That is not to say that there were no ecological effects. We do have evidence that the ash temporarily disrupted vegetative communities and it certainly choked and polluted some fresh water sources, probably causing harm to wildlife and maybe even humans.’

74,000 years ago, a large section of the Indonesian island of Sumatra exploded in one of the biggest volcanic eruptions of the past 2 million years. The global environmental impact of the ash and gas clouds from this ‘super-volcano’, known as Toba, is considered by some scientists to be the most catastrophic event the human species has ever endured. The project’s website and a full list of the team can be found at:  http://toba.arch.ox.ac.uk/.


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 kilometers of volcanic material was ejected during this super-eruption, dwarfing historical eruptions such as Krakatoa and Pinatubo.

At the time of the Toba eruption 74,000 years ago, humans shared the Earth with a number of similar species, including the cold-adapted Neanderthals and the dwarf Homo floresiensis. All these species made stone tools, gathered plants and hunted animals for their livelihood, and all survived the eruption and its after-effects. Nevertheless, when palaeo-climatic records are combined with genetic data that may indicate an abrupt decline in the number of humans (a genetic ‘bottleneck’) at about the time of Toba’s super-eruption, the possibility that we were driven to the edge of extinction deserves investigation.

 One of the most critical missing keys in understanding Toba’s impact is a lack of archaeological research looking at the actual remains left by humans who were directly affected by the YTT ashfall, particularly in India. We are not even sure if humans had reached India as part of the ‘Out of Africa’ dispersal by 74,000 years ago, although we do know that either we or a closely-related species watched the ash as it fell across the subcontinent. To resolve this problem, our main field research areas are in the Indian states of Andhra Pradesh (Kurnool District) and Madhya Pradesh (Sidhi District), both of which preserve Toba volcanic deposits along with archaeological evidence of the lives and environment of the people living there from well before until well after Toba’s eruption.

The research was supported by the Archaeological Survey of India and undertaken by an international team, led by Dr Michael Petraglia of Oxford University’s School of Archaeology, Professor Ravi Korisettar of Karnatak University (India) and Professor J.N. Pal of the University of Allahabad (India).

The archaeological and environmental research was undertaken in the Kurnool District of Andhra Pradesh, India, and in the Middle Son Valley, Madhya Pradesh. ** For more information about the Oxford School of Archaeology, go to www.arch.ox.ac.uk

For more information contact Dr Michael Petraglia on +44 (0)1865 275373 [mobile: 07855 955010] or email michael.petraglia@rlaha.ox.ac.uk

Alternatively, contact the University of Oxford Press Office on 01865 280534 or email press.office@admin.ox.ac.uk 

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