Featured Research

from universities, journals, and other organizations

New Evidence Provides An Alternative Route 'Out Of Africa' For Early Humans

Date:
October 15, 2008
Source:
University of Bristol
Summary:
The widely held belief that the Nile valley was the most likely route out of sub-Saharan Africa for early modern humans 120,000 year ago is challenged. A new team shows that wetter conditions reached a lot further north than previously thought, providing a wet 'corridor' through Libya for early human migrations. The results also help explain inconsistencies between archaeological finds.

A generalized map of the Sahara shows the location of the sample sites and the fossilized river courses.
Credit: Anne Osborne

The widely held belief that the Nile valley was the most likely route out of sub-Saharan Africa for early modern humans 120,000 year ago is challenged in a new paper in the Proceedings of the National Academy of Sciences.

Related Articles


A team led by the University of Bristol shows that wetter conditions reached a lot further north than previously thought, providing a wet 'corridor' through Libya for early human migrations. The results also help explain inconsistencies between archaeological finds.

While it is widely accepted that modern humans originated in sub-Saharan Africa 150-200 thousand years ago, their route of dispersal across the hyper-arid Sahara remains controversial. The Sahara covers most of North Africa and to cross it on foot would be a serious undertaking, even today with the most advanced equipment.

Well-documented evidence shows there was increased rainfall across the southern part of the Sahara during the last interglacial period (130-170 thousand years ago). The Bristol University team, with collaborators from the universities of Southampton, Oxford, Hull and Tripoli (Libya), investigated whether these wetter conditions had reached a lot further north than previously thought.

Anne Osborne, lead author on the paper said: "Space-born radar images showed fossil river channels crossing the Sahara in Libya, flowing north from the central Saharan watershed all the way to the Mediterranean. Using geochemical analyses, we demonstrate that these channels were active during the last interglacial period. This provides an important water course across this otherwise arid region." The critical 'central Saharan watershed' is a range of volcanic mountains formerly considered to be the limit of this wetter region.

The researchers measured the isotopic composition of snail shells taken from two sites in the fossil river channels and from the shells of planktonic microfossils in the Mediterranean. Despite being hundreds of kilometres from the volcanic rocks in the mountains of the Saharan watershed, these shells had a distinctly volcanic 'signature', very different from the other rocks surrounding the sites. Water flowing from these volcanic mountains is the only possible source of this signature.

Dr Derek Vance, senior author on the paper, added: "The study shows, for the first time, that monsoon rains fed rivers that extended from the Saharan watershed, across the northern Sahara, to the Mediterranean Sea. These corridors rivalled the Nile Valley as potential routes for early modern human migrations to the Mediterranean shores."

The similarities between Middle Stone Age artefacts in places like Chad and the Sudan, with those of Libya, strongly support this theory. "We now need to focus archaeological fieldwork around the large drainage channels and palaeo-lakes to test these ideas" said Nick Barton, a contributor to the project from the University of Oxford.


Story Source:

The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.


Journal Reference:

  1. Anne H. Osborne, Derek Vance, Eelco J. Rohling, Nick Barton, Mike Rogerson, and Nuri Fello. A humid corridor across the Sahara for the migration of early modern humans out of Africa 120,000 years ago. PNAS, DOI: 10.1073_pnas.0804472105

Cite This Page:

University of Bristol. "New Evidence Provides An Alternative Route 'Out Of Africa' For Early Humans." ScienceDaily. ScienceDaily, 15 October 2008. <www.sciencedaily.com/releases/2008/10/081014114848.htm>.
University of Bristol. (2008, October 15). New Evidence Provides An Alternative Route 'Out Of Africa' For Early Humans. ScienceDaily. Retrieved February 1, 2015 from www.sciencedaily.com/releases/2008/10/081014114848.htm
University of Bristol. "New Evidence Provides An Alternative Route 'Out Of Africa' For Early Humans." ScienceDaily. www.sciencedaily.com/releases/2008/10/081014114848.htm (accessed February 1, 2015).

Share This


More From ScienceDaily



More Fossils & Ruins News

Sunday, February 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Discovery Of 'Dragon' Dinosaur In China Could Explain Myths

Discovery Of 'Dragon' Dinosaur In China Could Explain Myths

Newsy (Jan. 30, 2015) A long-necked dinosaur from the Jurassic Period was discovered in China. Researchers think it could answer mythology questions. Video provided by Newsy
Powered by NewsLook.com
Battle of Waterloo Artefacts Go on Display at Windsor Castle

Battle of Waterloo Artefacts Go on Display at Windsor Castle

AFP (Jan. 29, 2015) Artefacts from the Battle of Waterloo go on display at Windsor Castle to mark the 200th anniversary of the momentous battle. The exhibition includes contemporary prints, drawings and personal belongings of French Emperor Napoleon. Duration: 00:31 Video provided by AFP
Powered by NewsLook.com
Mideast Skull Find Sheds Light on Human Ancestors' Trek

Mideast Skull Find Sheds Light on Human Ancestors' Trek

AFP (Jan. 29, 2015) A 55,000-year-old partial skull found in the Middle East gives clues to when our ancestors left their African homeland, and strengthens theories that they co-habited with Neanderthals. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Newsy (Jan. 28, 2015) Wrongly categorized as lizard fossils, snake fossils now show the reptile could have developed earlier than we thought — 70 million years earlier. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins