Modern people use fire to make stone tools from 72000 years ago

Evidence that early modern people living in the southern tip of Africa's coast 72,000 years ago used fire control techniques to increase the efficiency and quality of the process of making stone tools, okay reported in Science magazine on August 14.

A group of international researchers, including three researchers from Arizona State University Institute of Human Resources, concluded that 'this technique requires a new relationship between fire, heat and a structural change. stone structure '. In addition, their findings show the complex perception of early modern people.

Main author Kyle Brown, a University of Cape Town doctoral student, and director of Mossel Bay, South Africa, for ASU's Institute of Human Origin, said: 'Our illustration of the use process The heat showed that modern people in this early period had complicated fire control '.

Brown explained: 'We show that modern people 72,000 years ago, and perhaps 164,000 years ago in the South African coast, used fire furnaces carefully during the complicated process of heating stones. and change its properties, a process called heat treatment '.

Curtis Marean, project director and co-author of the article, said: 'Heat treatment technology starts with a genius moment - someone finds that heating will make the stone easier to trim'. Marean is a paleontologist at the Institute of Human Origin, and a professor at the School of Human Evolution and Social Change at the College of Science and Arts, Arizona State University.

Marean said: 'This knowledge is then passed on, and in a special way, this technique gradually becomes complicated because of the processing and what makes the heating, cooling, and cutting process also become complex'.

This creates a long process of technical development that scientists think requires a complex cognitive system, and maybe language to learn and teach.

The heating process transforms a stone called silcrete, which is not suitable for making tools, into excellent raw materials, allowing modern people to create advanced tools.

Eureka moment

Brown's research focuses on replicating the tools and remnants of the fabrication process discovered at some African archaeological sites to understand how and why humans have built and used them. those tools.

'In many field surveys with co-author David Roberts, a leading expert on silcrete formation, we were able to determine the location of the rocky outcrops with materials suitable for texture and color. Red of the silcrete artifacts we excavated at Pinnacle Point, " Brown said. " The silcrete we collected is not only suitable for tool making. "

Most of the detected silcrete has been cut very much. It is very rare to find a piece larger than a few centimeters. However, one day in 2007, at position 5-6 Pinnacle Point (PP5-6) Brown and Marean discovered a large silcrete piece lying in ash - the largest silcrete piece they have ever seen at an archaeological site, with a diameter of nearly 10 cm.

Brown said: 'It looks like it was lost in a fire pit'. He recalls that many of the silcrete instruments found at this location have a gloss that reminds him of the heat-treated tools he studied in the North American collection.

Evidence reported in Science on August 14 shows that modern people living in the southern coast of Africa 72,000 years ago used complex heat treatment to make blades and tools. other stuff. Unburnt silcrete (left) shows great changes in color and structure after being burned and trimmed (right). An international group, consisting of three researchers from Arizona State University's Institute of Human Origin, said the silcrete was discovered at a location 5km from Pinnacle Point excavation site, Mossel Bay, and most silcrete pieces. all found were meticulously cut. (Photo: Kyle Brown)

Marean said: 'That's when we developed the idea of ​​heat treatment. The relationship of silcrete-based ash, the silcrete red color, and its size are our eureka moments. '

To test his theory, Brown placed some silcrete rocks under a fire tunnel in a darkened area and set fire on top.

'When I came back to dig silcrete stone the next day, the results were amazing. After being heat-treated, the silcrete is reddish and easy to trim. The most important thing is that it looks identical silcrete from PP5-6 position. Using a heat-treated silcrete we can make real copies of the silcrete tool, " Brown said.

Grilled stone

'This is the beginning of the origin of the fire control technique, the bridge connects to later ceramic and metal techniques,' Brown added.

According to Marean, silcrete tools can be reused with many functions: excellent weapons, knives and great items are valuable when exchanging.

Marean commented: 'This explains why people spend a lot of effort to choose wood and heat treatment for their products'.

And the kilns used to test their theory 'are designed to mimic what humans in the past have done. So we not only baked silcrete but also baked steak while measuring the temperature with our thermometer ', Marean recounts.

Pictorial activities and modern human origins

Brown said: 'Our findings show that early modern people had a complex perception'.

Marean explains: 'The complex manifestations of early modern people in the southern coastal region, South Africa provide further evidence that this group of people may be the source of all other breeds. of modern people, and has appeared from 100,000 to 200,000 years ago in Africa '.

He said: 'There is no exact conclusion about when modern human activity appeared, but there is clear evidence of figurative activity from 70,000 years ago. Many researchers are looking for signs that modern cognitive complexes, and heat treatment are one of those signs. '

'Prior to our research, heat treatment was thought to have first appeared in Europe about 25,000 years ago. We have pushed this time back at least 45,000 years, and maybe, 139,000 years, and the first place to appear is Africa's southern tip, at Pinnacle Point '.

Africa is also at the center of another Marean finding - the oldest evidence on evidence that the marine food resource challenge and pigmentation change - reported in Nature October 17, 2007.

Marean said: 'When combined, these results broaden our knowledge of modern human origins, and show that something special in human awareness has taken place in the coastal area. South Africa'.

Around 50,000 to 60,000 years ago, 'these modern people left the warm territory of Africa and penetrated deep into the cold glacial environment of Europe and Asia, where they encountered Neanderthals'.

'About 35,000 years ago, Neanderthal populations were almost extinct, and modern humans dominated the land from Spain, China, to Australia' .

Marean concludes: 'The ability to control fire gives us an appropriate explanation of the rapid migration of Africans to the Eurasian snowpack - they are the masters of fire, heat and stoneware. , an important advantage to penetrate deep into the frozen lands of Neanderthals'.

NSF, others fund SACP4

Other members of the research team and co-author of the "Fire As Security Engineering tool of Early Modern Humans" article, including David Baun, Cape Town University; Andy IR Herries, University of New South Wales and University of Liverpool Zenobia Jacobs and Michael C. Meyer, University of Wollongong, Australia, Changal Tribolo, CNRS University in Bordeaux, France, David L. Roberts, Geological Sciences Council, South Africa, and Jocelyn Bernatchez, Source Institute human root, ASU.

They work together in the paleontological, paleontological, paleontological, and paleontological project, called SACP4, directed by Marean, with funding from the National Science Foundation and the Foundation. The Hyde family, with the help of Arizona State University teaching and research units, include the Institute of Human Origin, the Academy of Social Sciences.

'Our research team, working at Pinnacle Point near Mossel Bay, is the leader in the process of understanding our formation today, and we do this with real research. advanced and excellent experimental analysis locally ', Marean said.