AUSTIN, Texas—An international research team, including two geologists from The University of Texas at Austin, has unearthed ancient stone tools from an unusual geological setting in Africa that may contribute to solving the mystery of the geographic origins and adaptations of modern humans. The findings push back by 10,000 years the date for earliest evidence of human consumption of shellfish, marking the onset of a new type of feeding strategy in human evolution.
The tools were found within a fossil reef terrace on the Red Sea coast of Eritrea. They suggest that early humans were adapted to coastal marine environments and ate seafood, including clams, crabs, scallops and oysters, as early as 125,000 years ago. Eritrea is located north of Ethiopia and southeast of the Sudan. The findings will be published in the May 4 issue of the journal Nature.
Dr. Richard T. Buffler, a professor of geological sciences and senior research scientist at the UT Austin Institute for Geophysics, and Berhane Negassi Ghebretensae, a UT Austin graduate student from Eritrea, participated in the project. The project was headed by Dr. Robert C. Walter, a geologist and geochronologist with Mexico’s Centro de Investigacion Cientifica y Educacion Superior de Ensenada in Baja California. The research team includes scientists from Eritrea, the U.S., Mexico, the Netherlands, France and Canada.
The Paleolithic hand axes and obsidian flakes and blades were discovered in a fossil reef terrace near the Eritrean village of Abdur on the Gulf of Zula. The reef terrace is about ten kilometers long and about six to fourteen meters above current sea level.
“This is the oldest documentation in the world of the utilization of marine resources — clams, crabs and oysters — which are found in this reef along with the stone tools,” Buffler said. “The use of marine seafoods as a food source indicates a new behavior for early humans.”
“We would like to call this the ïfirst oyster bar,'” said Walter. “Abdur is an important site, not just because it is the earliest evidence for coastal marine occupation to date, but because it opens up the entire coast of Africa as a whole new realm of exploration for early human archaeology and paleontology.”
Buffler said the discovery “adds credence to the idea that early Homo sapiens originated in Africa, and migrated from there to Europe and Asia.”
The geographic origin of modern humans is a subject of intense debate. One school of thought contends that modern humans evolved semi-independently in Europe, Asia and Africa between 100,000 and 40,000 years ago. Another holds that modern humans evolved in Africa between 200,000 and 100,000 years ago, migrating to Eurasia at a later period. Direct paleontological, archaeological and biological evidence is required to resolve the conflict. The importance of finding ancient tools in Eritrea is that it favors an “out of Africa” migration.
“It is right on the potential migration route of modern humans out of Africa into Europe, Central Asia and over into Far Eastern Asia,” Buffler said.
The age of the stone tools found embedded in the rock was based on dating the fossil corals close to the tools by uranium-thorium mass spectrometric techniques to 125,000 years ago. The oldest previously known coastal site, the Klasies River mouth in South Africa, is estimated to be 115,000 years old, some 10,000 years later than the Abdur site. Rare occurrences of bifacial handaxes have been found on the surface of Pleistocene marine terraces from the Danakil Rift Valley of Eritrea and the Egyptian coast of the Red Sea. But they were not found in geological context, meaning direct estimates of their age were not possible.
“Nowhere else have stone tools been reported to be in a reef rock itself. So we know that the ancient people at Abdur were there on the reef and dropped these tools where they harvested their food. And the tools then became part of the geological record,” Buffler said.
Buffler said the team of researchers was traveling to another field area in the winter of 1997 when the group stopped near the reef. “We camped overnight and in the morning we started looking around and discovered the paleolithic tools in the reef,” Buffler said. The team, led by Walter and partly funded with a National Science Foundation grant, returned to study the area in more detail in January and February of 1999.
For more information, contact Dr. Richard T. Buffler at (512) 471-0448 or e-mail dick@ig.utexas.edu or contact Katherine Ellins at (512) 232-3251 or e-mail kellins@ig.utexas.edu at the UT Austin Institute for Geophysics. Contact Dr. Robert C. Walter, project director, in Ensenada, Baja California at (011) 52 6 174 4501 (ext.) 26044 or e-mail rwalter@cicese.mx. For information on photos, contact Marsha Miller at (512) 471-3151.
