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UNT Resource magazine >> Ancient Travelers

Ancient Travelers title logo Expertise in the emerging field of geoarchaeology led University of North Texas scientist Reid Ferring to conclusions that are causing archaeologists and anthropologists around the world to alter their perceptions of the early history of the human species. As a member of an international research team that unearthed two fossils in the Republic of Georgia in the summer of 1999 — an almost complete skull and a separate skullcap — the professor of archaeology, geology and physical geography played a crucial role in dating this historic discovery.
Reid Ferring photo Ferring and scientists from the Berkeley Geochronology Center determined that the fossil skulls (found beneath a medieval ruin at Dmanisi in the southern portion of the Republic of Georgia) are about 1.7 million years old. That conclusion confirms that the Dmanisi fossils are the oldest human remains found anywhere outside of Africa. Additionally, the scientists believe that their find's distinct similarities to Homo ergaster fossils (fossils dating back to the same time period in Kenya and believed to be the African version of Homo erectus) indicate that they have found the earliest known hominids to migrate out of Africa. This indicates that members of the human species left Africa hundreds of thousands of years earlier than scientists previously thought.
In a May 12, 2000, Science article, Ferring and his colleagues from the Republic of Georgia, France, Germany and the United States described the find and discussed its significance. Explaining his role in the discovery, Ferring was quoted on the international wires of the Associated Press and Reuters, in newspapers from Dallas to Istanbul, and on the air and Internet by CNN, MSNBC and the South Slavic Service of Radio Free Europe.

An early find
Throughout his career, Ferring, the current chair of UNT's Department of Geography, has been excavating and examining human fossils and artifacts along with any flora, fauna and physical features unique to the places they are discovered. One of his aims is to formulate a more complete history of human evolution and migration.
As a scientist with a special interest in the Pleistocene epoch (1.8 million to 11,000 years ago) and doctoral degrees in both geology and anthropology, Ferring combines his analyses of soil strata and sediments with his knowledge of human fossils. He can determine if a fossil is from the same era as the surrounding sediment or if the site has been disturbed.
He was recruited in 1993 to date the Dmanisi site and help settle disputes over the age of an early human mandible that had been discovered there. Some scientists believed the fossil to be more than 1 million years old, while others held firmly to the theory that early humans did not migrate from Africa into Eurasia and Europe until 500,000 years ago. Ferring says problems in dating the jawbone were compounded by the facts that the site had not yet been thoroughly dated and that the fossil's African connections were unclear. Since his initial involvement, Ferring has devoted a portion of each summer to work at the site. His research is funded by grants from the Louis S.B. Leakey Foundation and the National Science Foundation.

Dating methods
Ferring notes that because Dmanisi rests on a layer of volcanic rock, he was able to use radioactive isotopic dating at the site. Radioactive isotopic dating (in this case, potassium-argon radioactive dating) uses the phenomenon of radioactive decay to determine the age of a sample.
      Lava contains potassium, and over time the radioactive potassium decays into argon gas, which is released into the atmosphere. In solid lava, argon is trapped, so as time goes by the amount of argon in the rock increases. Because the Earth contains relatively little argon and scientists know the rate at which potassium decays into argon, they are able to determine the age of a sample by its ratio of potassium to argon.
      Ferring also used another method involving paleomagnetism, the permanent magnetism found in rocks, to determine the site's age. He explains that iron-rich crystals in rocks formed by cooling lava align with the Earth's magnetic field. Matching that knowledge with knowledge of a magnetic shift about 1.78 million years ago, he was able to find evidence of the shift through soil and sediment analysis. The deepest layers had normal magnetism, but the poles of higher layers were reversed.
      By combining both dating methods with the well-documented animal fossil record of Dmanisi, Ferring and his colleagues set the age of the site at 1.7 million years.

Changed perceptions
While wrapping up the research on the site's age in 1999, members of the team discovered the skull and skullcap in an area Ferring had long urged them to explore. Given the age of the site and the fossils' distinct similarities to the original African human species, the discoveries have altered previous perceptions about human migration and now, according to Ferring, will make Eurasia and Europe"fair game" for a new round of archaeological digs.
The team has unearthed more than 2,000 identifiable vertebrate fossils and more than 1,000 stone artifacts. Prior to this new find, scientists believed that early humans left Africa only after they had created sophisticated stone tools, but among the Dmanisi artifacts were simple tools similar to the ones used in Africa more than 2 million years ago. Ferring speculates that factors such as changes in social structure, physiology and ecology played a more significant role in the African human migration than previously imagined.
With the hopes of addressing the new questions raised by his recent findings, Ferring returned to Dmanisi this August to continue his research. UNT graduate student Johnny Byers of Fort Worth has also taken part in the historic work.

Unearthing the past
Ferring has another remarkable "oldest known" find to his credit — this one in North Texas. He made a major archaeological discovery in 1988 at the U.S. Army Corps of Engineers Lake Ray Roberts construction site near Aubrey. While out collecting fossils with his son, he discovered an 11,500-year-old campsite that is the oldest known, best dated and best preserved example of the Clovis people who populated the southern Plains roughly 12,000 years ago.
In recent years, Ferring also has excavated Paleolithic sites in Portugal to learn more about its Upper Pleistocene prehistory.
His newest project is to work with the Georgians to develop a five-year excavation plan. He hopes to continue his work east of Dmanisi into the drier parts of Georgia and south into Azerbaijan — as he continues to unearth the history of human civilization from the dust of the past.