In the last few decades , archaeologist thought that a gem age applied science call Levallois was invented in Africa before it spread elsewhere . Now , a discovery of thousands of artefact suggests that the technology evolved severally in different populations in Eurasia also . Thework , published inSciencethis week , describes the early use of goods and services of Levallois technology in Europe and Asia – challenge estimate that the innovation came from a exclusive origin and spread after the other human hejira from Africa .
Levallois engineering involves using a hammer - type prick to strike at the convex airfoil of a large gem , called a lithic core . This induce smaller eccentric to detach , and these are then retouch into a variety of puppet like blades , points , or hide out scrapers . Whatever is entrust of the lithic kernel ( now with focalize edge ) can be further pare into a tongue . These come along in the phonograph record across Eurasia 200,000 to 300,000 year ago , and earlier in Africa . Before this , other humans used the simpler bifacial engineering , where a stone is shaped into a hand axe by chipping scrap from two surface ; these chip are discarded afterwards . The development of Levallois , and the disappearance of bifaces , was used to mark the conversion from the Lower to the Middle Paleolithic , roughly 300,000 yr ago . But now we may involve to rethink this .
An international team lead byDaniel Adler from University of Connecticutexamined thousands of tools , varying greatly in elan , hollow from the Nor Geghi 1 sedimentary bed ( pictured below ) in Armenia ’s Southern Caucasus region . Preserved between two lava flows dated 200,000 and 400,000 years old , this was an important dispersal corridor for our nonextant ancestors move out of Africa .
Here , they found a location where bifacial and Levallois technology were used at the same fourth dimension . “ The compounding of these different engineering in one place intimate to us that , about 325,000 years ago , people at the site were innovative , " Adler says in anews release . The varied artifacts reflect the technical flexibleness and unevenness of a unmarried population – rather than chronologically distinct groups or multiple groups with distinct toolmaking traditions overlapping the same blank . Below is a sampling from Nor Geghi 1 : biface with two biface resharpening / thinning flake byproducts ( A ) , Levallois cores with Levallois flakes ( B , C ) , blade core with blade ( D ) .
With Levallois , detached flakes of predetermined size and shape are the desired products , while the flake detached during the making of bifaces are handle as waste . Comparisons across Africa , the Middle East , and Europe show that the evolution of Levallois was gradual and intermittent , occurring severally in populations sharing a plebeian technological ancestry . That is , Levallois technology evolved out of pre - existing biface engineering in unlike places at dissimilar times .
“ We would n’t have found this mixture if the Levallois engineering had only replaced the old method,”Adler separate Nature . “ The communities in all likelihood worked out for themselves how to make biface tools and then it was a short step to the Levallois method . ” The latter was more stinting , making optimal use of crude material – plus the little bias flakes are gentle to acquit . Furthermore , chemical substance analysis show that early world used obsidian outcrop 120 kilometer away , suggest they were up to of exploiting environmentally various territories .
Images : Daniel S. Adler
