Hints of earlier human exit from Africa
Submitted by coldrum on Thursday, 07 April 2011 Page Views: 3205
DiscoveriesStone Age people apparently took a surprisingly fast track out of Africa via an unexpected route — Arabia. Modern humans reached east Arabia, not far from the shores of southwestern Asia, as early as 125,000 years ago, according to a report in the Jan. 28 Science.Stone tools unearthed at an Arabian Peninsula rock shelter called Jebel Faya resemble sharpened points and cutting implements from East African sites of about the same age, says a scientific team led by physical geographer Simon Armitage (U of London) and archaeologist Hans-Peter Uerpmann (U of Tübingen, Germany.)
“New dates at Jebel Faya reveal that modern humans migrated out of Africa much earlier than previously thought, helped by global fluctuations in sea-level and climate change in the Arabian Peninsula,” Armitage says.
Modern humans originated in East Africa around 200,000 years ago, according to fossil and genetic evidence (SN: 2/26/05, p. 141).
DNA analyses of people living in different regions of the world today suggest that modern humans rapidly migrated from Africa to Asia around 60,000 years ago. Most researchers suspect that those ancient travelers moved through the Middle East or along Arabia’s south coast to reach Asia.
Many advocates of this later African departure suspect that a massive eruption of Indonesia’s Mount Toba around 74,000 years ago created a global “volcanic winter” that decimated modern human populations in Africa and rendered the Indian subcontinent uninhabitable for thousands of years.
Finds at Jebel Faya call that scenario into question, Armitage says. By about 130,000 years ago, decreased sea levels narrowed the Bab al-Mandab Strait separating East Africa from southwest Arabia to about 4 kilometers, allowing safe passage, the researchers estimate. Travelers could have then moved through a network of Arabian lakes and rivers created by warm, wet conditions at that time.
access
Jebel Faya, across the Persian Gulf from Iran, at another narrow water crossing where low sea levels would again have eased passage, Armitage says. Initial finds came from settlements dating to between about 3,000 and 10,000 years ago. Stone tools from roughly 38,000 years ago then turned up. In March 2006, investigators began to unearth tools from the ancient rock shelter, which was occupied between 100,000 and 125,000 years ago.
Finds at Jebel Faya, in particular the points and hand axes, closely resemble African Stone Age artifacts from around the same time, the scientists assert.
Still, archaeologists familiar with the new report say that Jebel Faya provides an important glimpse of an early push by modern humans into Arabia. That’s where agreement ends.
Ravi Korisettar (Karnatak U, Dharwad, India): Agrees with Armitage’s team that Arabia possibly served as hub between Africa and Asia for early modern human migrations. Modern humans’ stone tools found there come from sediment just below and above an ash layer deposited by the Toba eruption, suggesting that people arrived before the blast and endured its devastation, he says.
Jebel Faya and Jwalapuram tools display some similarities, but the oldest Indian finds date to shortly before Toba’s detonation 74,000 years ago and look more like African implements from that time.
Stanley Ambrose (U of Illinois, Urbana-Champaign): More likely that warm, wet conditions ~100,000 years ago prompted dead-end migrations of modern humans into Arabia and the Middle East. Previously unearthed fossils from several Israeli caves indicate that modern humans moved from Africa to the Middle East approximately 100,000 years ago but gave way to Neandertals by 70,000 years ago.
Also - Pollen evidence indicates that the Toba explosion set off 10,000 years of extreme cold and environmental devastation that nearly wiped out African Homo sapiens. Modern human survivors of the blast’s aftermath then colonized Asia, in his opinion.
Paul Mellars (University of Cambridge): agrees with that scenario. But like Shea, he sees critical size and shape differences between Jebel Faya and African stone tools. “These Arabian finds are too ambiguous to say what was happening with human movements out of Africa,” Mellars remarks.
If the Arabian discoveries indeed signal an early human migration to Asia, then excavations of Stone Age sites in Iran should produce similar tools, Shea predicts. Iran’s current political climate, however, makes such work difficult, he says. For more, see www.sciencenews.org.
Note: 65,000 years earlier than the generally accepted date for the first substantial human migrations beyond Africa. Argument for and against.
We would like to know more about this location. Please feel free to add a brief description and any relevant information in your own language.
Wir möchten mehr über diese Stätte erfahren. Bitte zögern Sie nicht, eine kurze Beschreibung und relevante Informationen in Deutsch hinzuzufügen.
Nous aimerions en savoir encore un peu sur les lieux. S'il vous plaît n'hesitez pas à ajouter une courte description et tous les renseignements pertinents dans votre propre langue.
Quisieramos informarnos un poco más de las lugares. No dude en añadir una breve descripción y otros datos relevantes en su propio idioma.