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World’s Oldest Stone Tools and Weapons Found in Ethiopia

World’s Oldest Stone Tools and Weapons Found in Ethiopia


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Researchers have unearthed some deliberately sharpened tools that date from over 2.5 million years ago. These artifacts are changing our understanding of the invention of tools and showing that our ancestors may have used a variety of basic technologies. They are also demonstrating that our early ancestors may have invented stone tools separately and repeatedly before they became widespread.

The find was made by a team of international and local experts, at the Bokol Dara site, in northern Ethiopia. In total, over 320 stone tools and weapons were uncovered. According to the Phys.org, they have been found, “close to the 2013 discovery of the oldest fossil attributed to our genus, Homo discovered at Ledi-Geraru.”

Stone Tools Used by Our Earliest Ancestor

The artifacts were found after a dig by hand on a steep slope in semi-desert. They are well-preserved because they were apparently discarded by early members of our genus by the side of a spring or lake. This body of water dried up and sediment covered the tools and weapons. The Independent quotes Vera Aldeias from the University of Algarve as saying that as a result “the site then stayed that way for millions of years.”

The stone tools were found near the oldest fossil attributed to the genus Homo. ( David R. Braun )

Flaked Stone Tools - Over 2.5 Million Years Old

Experts were able to accurately date the tools to between 2.58 and 2.61 million years ago. They were able to do this because they could date a layer of volcanic ash under the tools and other stone artifacts. This dating was then confirmed “magnetic signature of the site's sediments” according to Phys.org. This means that the tools were the oldest sharpened tools yet found. They are approximately 10,000 years older than the previous oldest that was found in Gona, Ethiopia.

The tools were made by chipping flakes off a stone that could be held in the hand. They usually were made by chipping off just a few flakes and were mainly used for the cutting of animal carcasses into the meat.

According to the New Scientist , “the style of the artifacts classifies them as Oldowan stone tools.” These were among the first tools that were capable of cutting and are different from the percussion tools, used by both early hominids and indeed primates. The stone artifacts were examined by a team from Arizona State University and George Washington University.

Blade Engda of the University of Poitiers lifts an artifact from 2.6 million year old sediment exposing an imprint of the artifact on the ancient surface below. Braun )

Stone Tools Invented Independently

The researchers found that the tools were very primitive and crude. The New Scientist quotes David Braun, one of the team members as stating that the artifacts had “significantly lower numbers of actual pieces chipped off a cobble than we see in any other assemblage later on.” This suggests that the makers were not as skilled or that they were not aware of more sophisticated stone tools produced in other areas.

This indicates to many that tools were developed by many groups and they may even have been re-invented several times. As a result, rather than seeing hominids learning tool-use from one group, they may have developed them independently, suggesting a great deal of ‘technological diversity’ among our early ancestors according to Phys.org.

A Technological Revolution

The stone artifacts found do not seem to have any connection to the so-called ‘Lomekwian tools’. These are tools used for banging and smashing items and are still used by chimpanzees in the jungle. It is something of a mystery as to how hominids transitioned from simple percussive tools to cutters and knives.

Eventually, the Oldowan sharpened tools were adopted by the general hominid populations. Tools became an integral part of their survival kit. The Oldowan style of stone tools became standardized over time and was then in general use for hundreds of thousands of years.

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Oldowan choppers, stone tools dating to 1.7 million years BC, from Melka Kunture, Ethiopia. (Archaeodontosaurus / CC BY-SA 4.0 )

The discovery of the flaked tools in Afer is of great significance because the style of tools is linked to a dramatic environmental shift. According to PNAS.org “the production of Oldowan stone artifacts appears to mark a systematic shift in tool manufacture that occurs at a time of major environmental changes. It is believed that these styles of tools helped humans to adapt to profound changes, as their environment changed from forest to one that was similar to a Savannah. These tools actually changed humans.” This is seen in the reduction in the size of our ancestor's teeth . Because they could cut-up their meat they did not need large teeth.

The find of the flaked artifacts is very significant. It is pushing back the date when our ancestors used more sophisticated cutting tools, which was very important in our evolution. It is demonstrating that our ancestors may have developed tools independently and may have had to re-invent them more than once. This is allowing us an insight into the world of our early ancestors. It is hoped that more tools and stone artifacts will soon come to light. The findings are going to be published in an upcoming edition of the Proceedings of the National Academy of Sciences.

Artistic interpretation of a female at the time of the emergence of Oldowan stone tools. (Esv / )


World’s Oldest Stone Tools and Weapons Found in Ethiopia - History

A publication of the Archaeological Institute of America

Stone Tool 2.52-2.60 million years old (Rutgers University) [LARGER IMAGE]

More than 2,600 sharp-edged flakes, flake fragments, and cores (cobbles from which flakes have been removed), found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia, have been dated to between 2.52 and 2.60 million years ago, pushing back by more than 150,000 years the known date at which humans were making stone tools.

Excavated between 1992 and 1994 by Rutgers University paleoanthropologists Sileshi Semaw and John W.K. Harris at three sites along the Gona River, the artifacts are similar in type to the 1.8-million-year-old tools found by Mary Leakey at Olduvai Gorge, Tanzania, in the 1960s. Known as Oldowan, the tool type has been found at other East African sites: Omo in southern Ethiopia, Lokalalei in northern Kenya, and Hadar, five miles east of the Gona River study area. Until now the oldest known examples were dated to 2.3 to 2.4 million years ago.

Because no hominid remains were found in association with the tools and they predate the oldest known remains of the genus Homo (see ARCHAEOLOGY, January/February 1997), the find has left the identity of the makers open to speculation. Semaw and his team will return to the field later this year in hopes of answering this question.

Using the argon/argon dating method on a layer of volcanic ash nearly seven feet above the tool-bearing deposit, Paul Renne of the Berkeley Geochronology Center determined that the Gona artifact assemblage was more than 2.52 million years old. A maximum date of 2.6 million years ago was obtained for mineral-rich sediments just below the artifacts using paleomagnetic dating.


Oldest stone tools pre-date earliest humans

They were unearthed from the shores of Lake Turkana in Kenya, and date to 3.3 million years ago.

They are 700,000 years older than any tools found before, even pre-dating the earliest humans in the Homo genus.

The find, reported in Nature, suggests that more ancient species, such as Australopithecus afarensis or Kenyanthropus platyops, may have been more sophisticated than was thought.

"They are significantly earlier than anything that has been found previously," said Dr Nick Taylor, from the National Centre of Scientific Research (CNRS) in France and the University of Leiden in the Netherlands.

"It's really quite astonishing to think what separates the previous oldest site and this site is 700,000 years of time. It's monumental."

The first tools from the site, which is called Lomekwi 3, were discovered in 2011. They were spotted after researchers took a wrong turn as they walked through the hot, dry Kenyan landscape.

By the end of 2012, a total of 149 tools had been found, and another field trip in 2014 has unearthed more still.

They include sharp flakes of stone, sheared off from larger rocks, which were most likely used for cutting.

Hammers and anvils were also excavated, some of which were huge in size.

"The very largest one we have weighs 15kg, which is massive," Dr Taylor told BBC News.

"On this piece, it doesn't show the signs of actually having been flaked to produce other artefacts. rather, it was probably used as an anvil.

"It probably rested in the soil and the other cobbles brought to the site, which were intended to be smashed apart to make tools, were struck against this large anvil."

Dating of the volcanic ash and minerals around the tools suggests that they are 3.3 million years old.

Until this discovery, the oldest examples of this technology were the Oldowan tools from Tanzania, which date to about 2.6 million years ago.

The researchers say the 700,000-year time difference reveals how manufacturing methods and use changed over time, growing more advanced.

The scientists do not know who made the tools discovered in Kenya.

Until now, some thought that Homo habilis - known as "handy man" - was the earliest of our ancestors in the Homo genus to use tools.

But with Homo fossils dating back to only 2.4-2.3 million years ago, it now seems unlikely that this was the first toolmaker.

Other finds, such as animal bones found in Ethiopia with cut marks that date to 3.39 million years ago, also suggest tool use began before H. habilis.

Scientists now believe the 3.3-million-year-old implements were crafted by another, more primitive species.

Dr Taylor said: "There are a number of possible candidates at present.

"There was a hominin called Kenyanthropus platyops, which has been found very close to where the Lomekwi 3 tools are being excavated. And that hominin was around at the time the tools were being made.

"More widely in the East African region there is another hominin, Australopithecus afarensis, which is famously known from the fossil Lucy, which is another candidate."

Neither of these species was assumed to be particularly intelligent - they had both human and ape-like features, with relatively small brains.

However the tools suggest they may have been smarter than assumed.

Dr Ignacio de la Torre, from University College London's Institute of Archaeology, described this as "a game-changing" find.

"It's the most important discovery in the last 50 years," he told BBC News.

"It suggests that species like Australopithecus might have been intelligent enough to make stone tools - that they had the cognitive and manipulative abilities to carry tasks like this out."


The Top Ten Human Evolution Discoveries from Ethiopia

Lucy, a partial Australopithecus afarensis skeleton, is one of the most famous hominid fossils ever found in Ethiopia. Image: 120/Wikicommons

Ethiopia may well deserve the title Cradle of Humankind. Some of the most famous, most iconic hominid fossils have been discovered within the country’s borders. Ethiopia can claim many “firsts” in the hominid record book, including first stone tools and the first Homo sapiens. Here’s a look at the country’s most important hominid finds.

Omo I and II (1967-1974): While excavating the Kibish Formation near the Omo River, Richard Leakey and his colleagues uncovered a partial skull and skeleton (Omo I) and a partial skull (Omo II) that are still thought to be the oldest examples of Homo sapiens. Dating to 195,000 years ago, Omo I has several features that clearly place it within our species, including a flat face, high forehead and prominent chin. Omo II, on the other hand, looks more primitive. While some researchers suggest its thicker skull and sloped forehead preclude it from being a true modern human, others say those features were probably within the range of variation for early H. sapiens.

Lucy (1974): While searching a dry gully at the site of Hadar, paleoanthropologist Don Johanson noticed a slender arm bone sticking up from the ground. He thought it belonged to a hominid. Then he noticed a thigh bone, some bits of a spine, a pelvis and some ribs. Eventually, Johanson and his colleagues unearthed approximately 40 percent of a hominid skeleton dating to roughly 3.2 million years ago. Named Lucy after the Beatles’ “Lucy in the Sky with Diamonds,” the skeleton is officially known as AL 288-1 and is arguably the most famous hominid fossil ever found. But it took a while for Johanson, with the help of paleoanthropologist Tim White, to figure out what Lucy was—Australopithecus afarensis—and her place in the human family tree. (For a firsthand account of Lucy’s discovery and the analysis of her remains, you probably can’t find a better book than Lucy: The Beginnings of Humankind by Johanson and Maitland Edey, even if some of the science is out of date.)

First Family (1975): Just a year after discovering Lucy, Johanson’s team got lucky again, finding a jumble of more than 200 A. afarensis fossils at the site of Hadar. The collection—representing as many as 17 individuals—was dubbed the “First Family” (official name: AL 333). Because the fossils contained both adults and youngsters, the First Family is a snapshot of variation within A. afarensis and offers a look at how an individual within the species might have grown up. Anthropologists are still trying to figure out what led to the demise of such a large group of hominids. A catastrophic flood is one theory death by over-eager carnivores is another.

Australopithecus garhi (1990, 1996-1998): Paleoanthropologists Berhane Asfaw and Tim White found a partial skull and other pieces of the 2.5-million-year-old species known as A. garhi in 1990 at the site of Bouri. Since then, no additional fossils have been unearthed (or, at least, matched to the species). Not much is known about A. garhi. Based on the length of a thigh bone, the species may have had slightly longer legs, and therefore a longer stride, than Lucy’s kind. Given the species’ age and where it was found, A. garhi may have been the hominid to make the oldest known stone tools (described next).

Oldest Stone Tools (1992-1994): At 2.6 million years old, the stone choppers, or Oldowan tools, at the site of Gona are a few hundred thousand years older than any other known stone tool. But the Gona tools’ status as earliest stone tool technology was recently challenged by another Ethiopian discovery. In 2010, archaeologists claimed that roughly 3.39-million-year-old mammal bones from Hadar contained scratches that could have only been made by a stone tool, implying stone tools were an even earlier invention than scientists had thought. Other researchers remain unconvinced that the markings were made by hominid butchering. And since no actual stone tools were found along with the bones, the Gona artifacts’ title of earliest known stone tools is still safe.

Ardi (1992-1994): Older than Lucy, Ardi is the most complete skeleton of an early hominid. The first pieces of the 4.4-million-year-old Ardi were uncovered in 1992 by one of Tim White’s graduate students, Gen Suwa, in the Middle Awash Valley. White and his colleagues then spent more than 15 years digging Ardi out and analyzing the skeleton. The hominid did not look like Australopithecus, so the researchers gave it a new name: Ardipithecus ramidus. Although the species walked upright on two legs, its form of bipedalism was quite different from that of modern people or even Lucy. Its discoverers think Ardipithecus represents an early form of upright walking and reveals how apes went from living in the trees to walking on the ground.

Ardipithecus kadabba (1997): Yohannes Haile-Selassie of the Cleveland Museum of Natural History unearthed hand, foot and other bones in the Middle Awash Valley that looked a lot like those of Ar. ramidus—only the bones were almost a million years older, with an age of about 5.8 million years. Teeth found in 2002 suggested the more ancient hominids deserved their own species: Ar. kadabba. It remains one of the earliest known hominid species.

Dikika Child (2003): From the site of Dikika comes the fossil of an approximately 3-year-old A. afarensis child dating to 3.3 million years ago. Sometimes called Lucy’s baby or Selam, it’s the most complete skeleton of an early hominid child, including most of the skull, torso, arms and legs. The fossil’s discoverer, Zeresenay Alemseged, of the California Academy of Sciences, and colleagues say the fossils suggest A. afarensis grew up quickly like a chimpanzee but was beginning to evolve slower growth patterns like those of modern humans.

Herto fossils (2003): Even if the Omo I and II fossils turned out not to be members of H. sapiens, Ethiopia would still be home to the earliest known members of our species. A team led by Tim White discovered three 160,000-year-old skulls in the Middle Awash Valley. Two belonged to adult H. sapiens while the other was of a child. Due to some features not seen in modern populations of humans, White and his colleagues gave the skulls their own subspecies: H. sapiens idaltu.

Australopithecus anamensis (2006): A. anamensis, the earliest species of Australopithecus, was already known from Kenya when a team led by Tim White of the University of California, Berkeley discovered more fossils of the species further north in Ethiopia’s Middle Awash Valley. The collection of roughly 4.2-million-year-old fossils is notable because it includes the largest hominid canine tooth ever found and the earliest Australopithecus femur.


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Oldest Javelins Predate Modern Humans, Raise Questions on Evolution

The oldest stone-tipped projectile weapons date to 280,000 years, study says.

The oldest known stone-tipped projectiles have been discovered in Ethiopia. The javelins are roughly 280,000 years old and predate the earliest known fossils of our species, Homo sapiens, by about 80,000 years.

These javelins are some 200,000 years older than previous examples of similar weapons, suggesting that modern humans and their extinct relatives had the know-how to create these sorts of complex thrown projectiles much earlier than often thought.

Scientists investigated stone tools unearthed at the Gademotta Formation on the flanks of an ancient, large collapsed volcanic crater in central Ethiopia's Rift Valley.

"Today, the area represents a ridge overlooking one of the four lakes in the vicinity, Lake Ziway," said researcher Yonatan Sahle, an archaeologist at the University of California, Berkeley. (See "Stone Spear Tips Surprisingly Old—'Like Finding iPods in Ancient Rome.' ")

During much of the Middle Pleistocene, about 125,000 to 780,000 years ago, "the area was overlooking an even bigger paleolake—a megalake composed of today's four separate lakes." Antelope and hippo remains have been recovered from the grassy, forested site.

The oldest artifacts at the site are roughly 279,000 years old. In comparison, the earliest known fossils of Homo sapiens, previously discovered at sites elsewhere in Ethiopia, are about 200,000 years old.

Pointed artifacts with damage suggesting they were used in spears are common at the site. The researchers focused on 141 such obsidian artifacts.

"We were only interested in testing the hypothesis that these tools were definitely used to tip spears," Sahle said. "The eureka came much later as we did the analysis and found out that the features we were dealing with were the result of throwing impact, not thrusting."

When pointed artifacts are used as weapons, V-shaped fractures, called fracture wings, can form at the moment of impact the apexes mark where the cracks started. Past experiments in materials such as obsidian have shown that the narrower the V-shapes of fracture wings, the higher the speed of the fracturing that created them.

The researchers discovered that the fracture wings seen in a dozen of these obsidian points suggest that the fracture cracking sped faster than 1,820 miles an hour (2,930 kilometers an hour). In experiments with thrusting spears, that's the maximum velocity seen in fracturing. And some of these artifacts apparently developed fractures after impact at speeds of up to 3,345 miles an hour (5,385 kilometers an hour), close to the maximum velocity seen with fracturing in thrown spears.

A number of these artifacts are among the oldest at the site, suggesting that javelins were used as early as 279,000 years ago. Such weapons are considered signs of complex behavior and were pivotal to the spread of modern humans.

"The implication is that certain behavioral traits that are considered complex and mostly only the domains of anatomically modern humans—such as the capacity to make and use projectiles—were not only incorporated into the technological repertoire of the African early Homo sapiens, but also had earlier roots and were present in populations ancestral to Homo sapiens," Sahle said.

The invention of projectile weapons was a major advance over thrusting spears carried in hand. Projectiles empowered prehistoric hunters to strike at a distance, reducing the risk of injury from dangerous animals and broadening the range of prey that people might capture.

Paleoanthropologist John Shea at Stony Brook University, in New York, who did not take part in this research, said these findings were sound.

"In this area, I can see these thrown spears probably being used against crocodiles, hippos, or some other big animal that one could get close to with boats," Shea said.

Stone-tipped hunting spears appear in the fossil record beginning about 500,000 years ago. However, these were thrusting spears, not thrown javelins. Until now, the oldest conclusive evidence dated such projectiles at 80,000 years old.

The creator of the most ancient obsidian javelins found at Gademotta was probably Homo heidelbergensis, the most likely ancestor to modern humans and Neanderthals, Sahle said. There may be no way to determine whether Homo sapiens discovered how to make these weapons independently or if they learned how to do so from Homo heidelbergensis.

Shea noted many complex behaviors started appearing between 200,000 and 300,000 years ago. "You see a shift in anatomical structures that would have allowed us to speak, and a shift toward more complex tools," he said. "I think the advances seen here in tools have to do with the emergence of language."

Shea cautioned not to read too much into the fact that these findings were made in Ethiopia. "It's often assumed that the earliest discovery of anything is the first instance of anything," Shea said. "This is just the oldest example we have so far of this technology—it doesn't mean that this is where it first evolved."

He suggested similar research could be conducted at other sites "to see how widespread similar points are, to see if everyone at this time is doing the same thing or if there are regional differences."

In the future, the researchers would like to discover when humans began using even more complex mechanically propelled weapons, such as the bow and arrow, and the spear-thrower known as the atlatl, which may have been developed between 60,000 and 100,000 years ago. These weapons may have helped modern humans expand out of Africa and outcompete Neanderthals, they noted.

The scientists detailed their findings online November 13 in the journal PLOS ONE.


UNIVERSITY PARK, Pa. — The origin of flaked-stone tool production is older than 2.58 million years ago, according to an international team of scientists working at the Bokol Dora 1 archaeological site in the Afar region of Ethiopia. Previously the oldest evidence of flaked-stone tools was younger than 2.58 million years ago.

"At first we found several artifacts lying on the surface, but we didn't know what sediments they were coming from," said Christopher Campisano, associate professor, School of Human Evolution and Social Change, Arizona State University. "But when I peered over the edge of a small cliff, I saw rocks sticking out from the mudstone face. I scaled up from the bottom using my rock hammer and found two nice stone tools starting to weather out."

Bokol Dora 1 is near Lee Adoyta, where in 2013 archaeologists found the fossil jaw bone of a human ancestor dating to about 2.78 million years ago.

Recently, stone tools for hammering, dating to 3.3 million years ago, were found in Kenya, but these are not flaked-stone tools. The process used to make flaked-stone tools, flint knapping, systematically chips off smaller sharp-edged tools from larger nodules of stone, creating tools suitable for scrapping, cutting and piercing. Earlier stone tools like those found in Kenya or those sometimes used by chimpanzees and monkeys are used to hammer and bash foods such as nuts and shellfish.

The archaeologists working at the Bokol Dora 1 site wondered how these flaked tools fit into the increasingly complex picture of stone tools production. These oldest artifacts, ascribed to the "Oldowan," were distinct from the tools made by chimpanzees, monkeys and even earlier human ancestors.

Flaked stone tools Flaked-stone tools from Bokol Dora 1 are shown as 3D models without surface characteristics.

"We expected to see some indication of an evolution from the Lomekwian (Kenya) to these earliest Oldowan tools," said Will Archer, Max Planck Institute for Evolutionary Anthropology, Leipzig and the University of Cape Town. "Yet when we looked closely at the patterns, there was little connection to what is known from older archaeological sites or to the tools modern primates are making."

Recovery of the flaked-stone tools took several years because the archaeologists needed to carefully excavate through many layers of sediment to reach the layer that contained animal bones and hundreds of pieces of chipped stone.

"These tools were dropped by early humans at the edge of a water source and then quickly buried," said Vera Aldeias, interdisciplinary Center for Archaeology and Behavioral Evolution, University of Algarve, Portugal. "The site then stayed that way for millions of years."

Kaye Reed, director of the Ledi-Geraru Research Project and research associate in the Institute of Human Origins, Arizona State, noted that the animal bones found with these tools are similar to those found a few kilometers away at Ledi-Geraru with the 2.78 million-year-old jaw bone.

The researchers used two methods to date the layer where they found the flaked tools. Because they found the fossil layer above a layer of consolidated volcanic ash, they dated the ash layer using Argon40/Argon39 dating to about 2.58 million years ago.

"We found and mapped a gray ash layer meters below the archaeological site," said Erin DiMaggio, assistant research professor in geoscience, Penn State. "We were really fortunate that it contained feldspar minerals and we successfully dated them to constrain the age of the archaeological layer."

Archaeologists screen dirt looking for flaked-stone tools and other artifacts at Bokol Dora 1.

They also used magnetostratigraphic dating, a method useing the status of the Earth's magnetic field at the time the sediment was laid down, to constrain the date. Throughout the Earth's history, the magnetic poles have flipped many times. The researchers found that the magnetic signature at the site indicates that it is older than 2.58 million years ago and therefore older than all previously known sites in the area. They report their findings today (June 3) in the Proceedings of the National Academy of Sciences.

The researchers found that the flaked-stone tool technology at Bokol Dora 1 was different than the stone tool technology at an older site in Kenya. They suggest that while many of our human ancestors had the ability to make stone tools, the change in technology to producing sharp-edged flakes would have increased the amount and variety of things to eat and that this change in diet may have been important in the evolution of our genus Homo.

"Given that primate species throughout the world routinely use stone hammers to forage for new resources, it seems very possible that throughout Africa many different human ancestors found new ways of using stone artifacts to extract resources from their environment," said David Braun, associate professor of anthropology, George Washington University. "If our hypothesis is correct, then we would expect to find some type of continuity in artifact form after 2.6 million years ago, but not prior to this time period. We need to find more sites."


150,000 Stone Tools Found in North America Add More Evidence That We're Wrong About The First Settlers

Until recently, if you asked most experts when the first human beings arrived and settled in North America, you'd get an answer along the lines of 13,500 years ago.

But over the last few years, evidence has been mounting that humans arrived at the continent earlier. And now a massive discovery of hundreds of thousands of stone tools suggest we might have to push the date of human settlement back by at least 2,500 years.

Artefacts recently uncovered at a dig called the Gault site in Texas appear to predate by thousands of years one of the oldest and best studied collections of relics we have, named Clovis after the spot where the first group of tools was found in the 1920s, in Clovis, New Mexico.

Since the initial discovery, stone tools dating to the Clovis period have been uncovered in various other places across North and South America, but the new find adds to the growing body of evidence that people arrived on this continent long before then.

"These projectile points are unique," says one of the researchers, Thomas Williams from Texas State University. "We haven't found anything else like them."

"Combine that with the ages and the fact that it underlies a Clovis component and the Gault site provides a fantastic opportunity to study the earliest human occupants in the Americas."

Williams and his team have uncovered around 150,000 stones modified by the hands of humans at the Gault dig, which is around 64 kilometres (40 miles) north of Austin, analysing close to 200 of them. They would have been used as blades, engraving tools, scrapers, and more.

Some of these objects cloud date as far back as 20,000 years, according to the researchers, and look to be at least 16,000 years old – that's based on an optically stimulated luminescence process, where exposing artefacts to light and measuring the emitted energy can determine when those artefacts last saw sunlight.

Add the dating to the techniques used to make these tools, which seem to be different from the various Clovis finds, and it looks as though we might have to find "a more elaborate framework" for how civilisation begin in this part of the world, the team writes.

This isn't the first occasion that the Clovis timeline has been called into question, and the some researchers are now moving towards the idea that people were living in the Americas much earlier.

All kinds of clues – like how humans might have travelled from Asia – are being reassessed.

This particular part of the world would have appealed as a place to settle – it would have offered plenty of wild springs for feeding people and animals, as well as an abundance of flinty outcrops for fashioning tools like these.

Indeed the site has a long history, and the researchers have previously found tools matching the date and design of previous Clovis finds at the dig too.

All the signs from the Gault dig seem to suggest that the tool-making technology of the Clovis period spread across a population that was already established and indigenous, rather than one that had just arrived, the researchers conclude.

So it looks as if we have a new page of history to write, and an earlier starting date for humans in North America – at least until the next discovery.


Flint as a Gemstone

Flint is a very durable material that accepts a bright polish and often occurs in attractive colors. It is occasionally cut into cabochons, beads, and baroque shapes for use as a gemstone. It is also used to produce tumbled stones in a rock tumbler.

Most people have heard of a gem material called "jasper". Jasper is an opaque variety of cryptocrystalline quartz. It obtains its color and opacity from a large amount of included mineral particles. Flint and jasper are similar materials and both are varieties of a gem material known as "chalcedony".

Chalk Cliffs: Chalk cliffs can be an excellent place to find flint. As the soft chalk weathers away, flint nodules fall to the beach below. Image of chalk cliffs along the Baltic Sea, photo copyright iStockphoto / hsvrs.


Homo erectus used two different kinds of stone tools

The discovery of skull fragments alongside different types of stone tools in Ethiopia sheds new light on the lifestyle of the ancient hominin Homo erectus. It dispels the idea that each hominin species used just one type of tool technology and indicates that H. erectus was more behaviourally flexible than we thought.

Sileshi Semaw at the National Centre for Research on Human Evolution in Spain and his colleagues identified two H. erectus skulls at a site in Gona, Ethiopia. One was 1.26 million years old and the other dated back at least 1.5 million years. Unusually, the skulls were found directly alongside various stone tools.

“This is good evidence that these hominins were the creators of those artefacts,” says Michael Rogers at Southern Connecticut State University, who was part of team that made the discovery. “That means you can get a better handle on what kind of tools they were really using.”

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H. erectus evolved around 2 million years ago in Africa and was one of the first species in our genus, Homo. Compared with earlier hominins, members of this species had relatively large brains and were adept tool-makers. They invented the so-called Acheulian tools, such as teardrop-shaped hand axes, which superseded the older and simpler Oldowan tools.

Read more: Ancient humans: What we know and still don’t know about them

Hand axes are a multipurpose tool, a kind of Stone Age Swiss army knife. It was thought that once these sophisticated implements had been invented, H. erectus stopped using the more primitive Oldowan tools, which are sharp-edged stone flakes.

The discoveries at Gona dispel this notion, showing that both types of tool were used at the same time. “They were using both technologies as they saw fit,” says Semaw.

The skeletal remains also revealed other information about these hominins. The older skull was much smaller than the more recent one. It has the smallest cranial capacity ever found for H. erectus, and was probably female, says Semaw. The other skull was larger and sturdier with big brow ridges, and probably male, implying large physical differences between the sexes.

Other clues about the lifestyle of the Gona H. erectus population come from analysing isotopes in teeth, which show they had a varied diet, possibly consisting of eggs, insects, woodland plants and grazing animals.

“Not only were they physically quite variable, but their tool use behaviour was also quite variable,” says Rogers. “This emphasises that they were incredibly adaptable to their local settings. On all fronts – biological, ecological and behavioural – our evidence suggests more variability and more flexibility.”

Journal reference: Science Advances, DOI: 10.1126/sciadv.aaw4694

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