The now arid zone of the Eastern Mediterranean was once green savannahs and grasslands that provided an ideal passage for multiple early human movements out of Africa, a new study finds.
Published in Science Advances, the international research team’s findings support the growing consensus for a well-watered Jordan Rift Valley that funnelled migrants into western Asia and northern Arabia.
Professor Michael Petraglia, Director of Griffith University’s Australian Research Centre for Human Evolution, is a co-author on the paper which examined sediments of paleo-wetlands and dated them using luminescence dating methods.
“The research in the Jordan Rift Valley and Plateau zone clearly shows a humid corridor existed, supporting research in Arabia and the Levant that terrestrial routes were favoured by hunter-gatherers wandering across terrestrial ecosystems outside Africa,” Professor Petraglia said.
“The presently harsh environment of the Levant and Arabia are the key regions through which members of the genus Homo, including our species Homo sapiens, had to pass through when leaving Africa and moving into Eurasia.
“Our new research sheds light on the region around the Jordan Rift Valley as potentially a key successful dispersal route for modern humans during the last interglacial period (Marine Isotope Stage or MIS 5, between ~129-71,000 years ago.
“The northern corridor crossing the Nile River, into Sinai Peninsula to the Levant region in Arabia and beyond is the only terrestrial route out of Africa.”
The research team successfully integrated the chronometric data along with paleoclimatic records to examine this corridor.
This record is associated with the formation of the paleo-wetlands, which is associated with stone tools that have been found in the area dated to about 84 thousand years ago.
Dr Mahmoud Abbas, a Jordanian, who is the study’s lead author from Shantou University, China, said: “The Levant acted as a well-watered corridor for modern humans to disperse out of Africa during the last interglacial, and we have now demonstrated this is the case in the Jordan Rift Valley zone.”
“The paleohydrological evidence from the Jordan desert enhances our understanding of the environmental setting at that time.”
“Rather than dry desert, savannah grasslands would have provided the much-needed resources for humans to survive during their journey out of Africa and into southwest Asia and beyond.”
Petraglia said: “Our research demonstrates the intimate relationship between climate change and human survival and migrations.”
The project was organized by Professor Zhongping Lai, the head of the luminescence dating laboratory at Shantou University, China, with joint collaborators of scientists from China, Jordan, United Kingdom, Australia and Czech Republic.
The research ‘Human dispersals out of Africa via the Levant’ has been published in Science Advances.