Thursday, 1 December 2011

The Exodus From Africa Occured Far Earlier Than Previously Thought

It has been a long held hypothesis that humans first left Africa via the Bad el Mandab, also known as the Gates of Grief, 60,000 to 70,000 years ago, becoming the dominant species on all continents around 10,000 years ago. This theory was backed up by archaeological evidence from stone tools, the remains of the first pioneers and genetic mapping.
Diagrams of the Nubian stone tools found in Southern Oman

However astonishing new stone tool discoveries show that the exodus from Africa is far more ancient than first thought. An international team of archaeologists and geologists excavating in the Dhofar Mountains in Southern Oman, discovered a series of stone tools from more than 100 sites. These artefacts were rather special as they belonged to the Nubian stone tool culture which, until now, was only known in Egypt. The tools show that the people who created this culture migrated out of Africa, bringing their technology with them.

While this might not sound very exciting, the finds are ground-breaking due to their date. Using a dating method called optically stimulated luminescence, the researchers found that the tools were 106,000 years old, making them the oldest known evidence of human occupation outside of Africa and over 30,000 years older than the previous proposed dates for the beginnings of global migration. The discovery also contradicts the long-held theory that humans travelled along the line of the coast of the Arabian Gulf.

The stone tools were found far inland suggesting that humans did not follow the coast. This could be seen as a poor move heading into a vast desert. Yet the date of the stone tools coincides with a wet climatic phase. Then the Arabian desert was a lush, fertile scrubland. Humans could have survived the journey across the Gulf. There is fossil evidence also to support this new theory: the remains of 20 individuals found in the Es Skhul and Qafzeh Caves in Israel.

It was originally thought that these humans represented a first, failed attempt to leave Africa. However their geographical location, as well as their age (around 80,000 to 100,000 years old), provides more evidence for the inland migration theory. The Skhul and Qafzeh remains may actually be part of the first succesful exodus, representing the next phase of the migration after the stone tools. Future archaeological evidence could provide us with a link between the bones and the tools; once and for all, marking the route out of Africa.