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UNIVERSITY PARK, PA. – According to an international team of scientists working at the archaeological site of Bokol Dora 1 in the Afar region of Ethiopia, the production of flake tools dates back more than 2.5 billion years. Previously, the oldest evidence of glittering tools was less than 2.58 million years old.
"At first we found several artefacts on the surface, but we did not know what sediments they came from," said Christopher Campisano, an associate professor at the Arizona State University School of Human Evolution and Social Change. "But when I peeked over the edge of a small cliff, I saw rocks coming out of the mudstone face." I climbed up the bottom with my hammer and I found two beautiful stone tools that were starting to degrade. "
Bokol Dora 1 is located near Lee Adoyta, where in 2013 archaeologists discovered the fossil jawbone of a human ancestor dating to about 2.78 million years ago .
Recently, stone hammer tools, dating back to 3.3 million years ago, have been discovered in Kenya, but they are not flake tools. The process used to make snowflake tools, flint cutting, involves systematically shredding the smallest sharp-edged tools from large stone nodules, creating appropriate tools for stripping, cutting and drilling. Earlier stone tools, such as those found in Kenya or those sometimes used by chimpanzees and monkeys, are used to hammer and hit foods such as nuts and shellfish.
Archaeologists working on the site of Bokol Dora 1 have wondered how these tattered tools fit into the increasingly complex picture of stone tool production. These oldest artefacts, attributed to the "Oldowan", were distinct from the tools made by chimpanzees, monkeys, and even older human ancestors.
Enamelled stone tools The Bokol Dora 1 enamelled stone tools are presented as 3D models without surface features.
"We expected to see an indication of an evolution from Lomekwian (Kenya) to these early tools of Oldowan," said Will Archer, of the Max Planck Institute of Evolutionary Anthropology of Leipzig and University of Cape Town. "Yet, when we looked closely at the models, there was little connection to what we know of the older archaeological sites or the tools that modern primates make."
The recovery of flake tools took several years, as archaeologists had to carry out thorough excavations in many layers of sediment to reach the layer containing animal bones and hundreds of chipped stone fragments.
"These tools were abandoned by the first humans at the edge of a water source, and then quickly buried," said Vera Aldeias, Interdisciplinary Center for Archeology and Behavioral Change of University of the Algarve, Portugal. "The site has stayed that way for millions of years."
Kaye Reed, director of the Ledi-Geraru research project and research associate at the Institute of Human Origins in Arizona, said the animal bones found with these tools are similar to those found a few miles away at Ledi-Geraru, with 2.78 million euros. bone of the jaw
The researchers used two methods to date the layer where they found the frayed tools. Because they found the fossil layer over a layer of consolidated volcanic ash, they dated the ash layer with Argon40 / Argon39 about 2.58 million years ago.
"We found and mapped a layer of gray ash a few meters below the archaeological site," said Erin DiMaggio, assistant professor of geoscience research at Penn State. "We were fortunate to be able to contain feldspar minerals and we have dated them successfully to limit the age of the archaeological layer."
Archaeologists examine the earth for stone tools and other artefacts at Bokol Dora 1.
They also used magnetostratigraphic dating, a method using the state of the Earth's magnetic field at the time of sediment deposition, to constrain the date. Throughout the history of the Earth, the magnetic poles have turned several times. The researchers found that the magnetic signature on the site indicated that it dates back more than 2.58 million years and is therefore older than all known sites in the region. They report their findings today (June 3) in the Proceedings of the National Academy of Sciences.
The researchers found that the Bokol Dora 1 flake tool technology was different from that of stone tools from an older site in Kenya. They suggest that while many of our human ancestors were capable of making stone tools, the change in technology to produce sharp-edged flakes would have increased the amount and variety of things to eat and that regime change could have been important in the future. evolution of our genus Homo.
"Since primate species around the world routinely use stone hammers to search for new resources, it seems very likely that many human ancestors have found new ways to use stone artifacts to extract resources." their environment, "said David Braun, Associate Professor. of Anthropology, George Washington University. "If our hypothesis is correct, then we would expect to find a form of continuity in the form of artifact after 2.6 million years, but not before that period.We must find more sites."
The US National Science Foundation and the John Templeton Foundation supported this research.
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