A team of researchers from Bern University has found that humans occupied the Arabian desert as long ago as 130,000 years when several phases of humid climate reigned. These intervals enabled modern humans to spread from Africa across the Arabian Peninsula and then to the rest of the world.
Fossil lake deposits from the Rub 'al Khali desert in southwestern Saudi Arabia.
Credit: Image: Thomas Rosenberg/University of Bern
Sudies of fossil lake sediments and stalagmites showed Bern geologists that the Arabian desert during the last 130,000 years was transformed three times into a green savanna with lakes. These humid climate phases lasted only between 4000-7000 years but long enough for the spread of Homo sapiens from Africa to Europe and Asia, during which these lush periods were of vital importance. These findings are based on the results of the doctoral thesis of Thomas Rosenberg, which he wrote under the direction of Professors Frank Preusser, Dominik Fleitmann and Albert Matter, Institute of Geology and Oeschger Centre for Climate Research at the University of Bern. The latest results from the Swiss National Science Foundation (SNSF) supported the work which has been published in the latest issue of the journal "Geology".
Arabian Peninsula as a land bridge
On the way to a "global species' modern humans, about 150,000 years ago, left East Africa. For decades, scientists dealt with the question of which path was taken by the Homo sapiens and when they could cross the inhospitable deserts of North Africa and Arabia. It was previously suggested that our ancestors migrated from the Nile Valley and the Middle East to the north. "The Arab peninsula was neglected as a land bridge for modern man for a long time, as research had focused on North Africa and the Middle East," said Dominik Fleitmann."This will change as a result of our research results and hopefully soon."
Credit: University of Bern/Dominic Fleitmann
A green corridor for human life
The research team from the University of Bern studied fossil lake sediments from the Arabian desert and used so-called Luminescence Dating, by which minerals are studied on stored light and so dated. The researchers studied the period between 130,000 and 75,000 years before our time to find three intervals, where in Arabia there was a very humid climate. These humid periods occurred approximately 125,000, 100,000 and 80,000 years ago. Dating and geochemical analysis of stalagmites also support this assumption. The increase in precipitation changed so the Arab desert transformed into a green savannah, with hundreds of lakes, which formed lakes up to 50 kilometers in size and 30 feet deep. Even today you can find stone tools on the ancient shores of these lakes, which testify that man lived in the Arabian desert from 130,000 to 75,000 years ago.
Homo sapiens took advantage of his opportunities
The investigations of the Bern geologists also show that the Arabian desert from 80,000 to 10,500 years ago experienced no more significant rainfall, and it finally transformed into an insurmountable geographical barrier for modern humans. Homo sapiens only had three relatively short windows of time to cross the Arabian Peninsula on their way north. "All evidence indicates that Homo sapiens used this time window, and Arabia is of importance for the propagation of our species" says geologist Fleitmann
Contacts and sources:
A green corridor for human life
The research team from the University of Bern studied fossil lake sediments from the Arabian desert and used so-called Luminescence Dating, by which minerals are studied on stored light and so dated. The researchers studied the period between 130,000 and 75,000 years before our time to find three intervals, where in Arabia there was a very humid climate. These humid periods occurred approximately 125,000, 100,000 and 80,000 years ago. Dating and geochemical analysis of stalagmites also support this assumption. The increase in precipitation changed so the Arab desert transformed into a green savannah, with hundreds of lakes, which formed lakes up to 50 kilometers in size and 30 feet deep. Even today you can find stone tools on the ancient shores of these lakes, which testify that man lived in the Arabian desert from 130,000 to 75,000 years ago.
Homo sapiens took advantage of his opportunities
The investigations of the Bern geologists also show that the Arabian desert from 80,000 to 10,500 years ago experienced no more significant rainfall, and it finally transformed into an insurmountable geographical barrier for modern humans. Homo sapiens only had three relatively short windows of time to cross the Arabian Peninsula on their way north. "All evidence indicates that Homo sapiens used this time window, and Arabia is of importance for the propagation of our species" says geologist Fleitmann
0 comments:
Post a Comment