lunes, 29 de septiembre de 2014

Stone tools discovery prompts re-think of African theory (Armenia)

A new discovery and subsequent analysis of thousands of Stone Age tools has provided a major insight into human innovation 325,000 years ago and how early technological developments spread across the world, according to research published in the journal Science. It shows that technological innovation occurred intermittently throughout the Old World, rather than spreading from a single point of origin, as previously thought.
The belief that a type of technology known as Levallois – where the flakes and blades of stones were used to make useful products such as hunting weapons was invented in Africa and then spread to other continents as the human population expanded can now be discounted say the researchers.
At an archaeological site in Armenia called Nor Geghi 1, the researchers discovered that these types of tools already existed there between 325,000 and 335,000 years ago, suggesting that local populations developed them out of a more basic type of technology, known as biface, which was also found at the site.
Archaeologists have argued that Levallois technology was invented in Africa and spread to Eurasia with expanding human populations, replacing local biface technologies in the process. This theory draws a link between populations and technologies and thus equates technological change with demographic change. The co-existence of the two technologies at Nor Geghi 1 provides the first clear evidence that local populations developed Levallois technology out of existing biface technology.

Preserved between two lava flows

Nor Geghi 1, is a unique site preserved between two lava flows dated to 200,000–400,000 years ago. Layers of floodplain sediments and an ancient soil found between these lava flows contain the archaeological material. The dating of volcanic ash found within the sediments and detailed study of the sediments themselves allowed researchers to correlate the stone tools with a period between 325,000 and 335,000 years ago when the Earth’s climate was similar to today’s.
Dr Simon Blockley and Dr Alison MacLeod, from the Department of Geography at Royal Holloway, analysed the volcanic material that preserved the archaeological site in the village of Nor Geghi, in Kotayk Province. By employing innovative procedures developed at Royal Holloway, they extracted suitable material to help date the Levallois tools.
“The combination of these different technologies in one place suggests to us that, about 325,000 years ago, people at the site were innovative,” says Daniel Adler, associate professor of Anthropology at the University of Connecticut, and the lead author of the study. Moreover, the chemical analysis of several hundred obsidian artefacts shows that humans at the site utilized obsidian outcrops from as far away as 120 kilometres (approximately 75 miles), suggesting they must also have been capable of exploiting large, environmentally diverse territories.
“Our findings challenge the theory held by many archaeologists that Levallois technology was invented in Africa and spread to Eurasia as the human population expanded. Due to our ability to accurately date the site in Armenia, we now have the first clear evidence that this significant development in human innovation occurred independently within different populations.” said Dr Blockley.

An innovation

Archaeologists argue that Levallois technology was a more innovative way of crafting tools, as the flakes produced during the shaping of the stone were not treated as waste but were made at predetermined shapes and sizes and used to make products that were small and easy to carry. With the more primitive biface technology, a mass of stone was shaped through the removal of flakes from two surfaces in order to produce bigger tools such as a hand axes.
It is the novel combination of the shaping and flaking systems that distinguishes Levallois from other technologies, and highlights its evolutionary relationship to biface technology. Based on comparisons of archaeological data from sites in Africa, the Middle East, and Europe, the study also demonstrates that this evolution was gradual and intermittent, and that it occurred independently within different human populations who shared a common technological ancestry, says Adler. In other words Levallois technology evolved out of pre-existing biface technology in different places at different times.
This conclusion challenges the view held by some Archaeologists that technological change resulted from population change during this period. “If I were to take all the artefacts from the site and show them to an archaeologist, they would immediately begin to categorize them into chronologically distinct groups,” Adler said. In reality, the artefacts found at Nor Geghi 1 reflect the technological flexibility and variability of a single population during a period of profound human behavioural and biological change. These results highlight the antiquity of the human capacity for innovation.

Source: Past Horizons:

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