Saturday, September 27 2014

Artifacts uncovered at a 325,000-year-old archeological site in Armenia
suggest that, contrary to what scientists previously thought, Homo sapiens were
not the first to develop precision tools, csmonitor.com says referring to an
article published by The Science Mag, Friday.

 

"The Lower to Middle Paleolithic transition
(~400,000 to 200,000 years ago) is marked by technical, behavioral, and
anatomical changes among hominin populations throughout Africa and Eurasia. The
replacement of bifacial stone tools, such as handaxes, by tools made on flakes
detached from Levallois cores documents the most important conceptual shift in
stone tool production strategies since the advent of bifacial technology more
than one million years earlier and has been argued to result from the expansion
of archaic Homo sapiens out of Africa. Our data from Nor Geghi 1, Armenia,
record the earliest synchronic use of bifacial and Levallois technology outside
Africa and are consistent with the hypothesis that this transition occurred
independently within geographically dispersed, technologically precocious
hominin populations with a shared technological ancestry," The Science Mag
writes. "Levallois technology is the name for the stone knapping technique
used to create tools thousands of years ago. 
The technique appeared in the archeological record across Eurasia 200 to
300 thousand years ago (ka) and appeared earlier in Africa. Adler et al.
challenge the hypothesis that the technique's appearance in Eurasia was the
result of the expansion of hominins from Africa.  Levallois obsidian artifacts in the southern Caucasus, dated at
335 to 325 ka, are the oldest in Eurasia. This suggests that Levallois
technology may have evolved independently in different hominin populations. Stone
technology cannot thus be used as a reliable indicator of Paleolithic human
population change and expansion," the Science Mag writes.

 

 

Nearly two dozens of scientists, including Samvel
Nahapetyan and Boris Gasparyan from the University of Connecticut launched
excavations in the Hrazdan gorge, near Nor Geghi village, in Armenia. 

 

 

"Recent excavations at Nori Geghi 1 uncovered
Levallois tools dating back long before H. 
sapiens migrated into Eurasia. This suggests that the technique evolved
independently in both Africa and Eurasia," says paleoanthropologist Daniel
Adler, an anthropology professor at the University of Connecticut in Storrs,
Conn., and lead researcher on the Nori Geghi 1 dig, csmonitor reports.

 

The archeological record shows that many branches of
early hominids used a bifacial stone toolmaking techniques to create somewhat
clunky tools such as hand-axes. Bifacial technology, likely developed 1.75
million years ago, involves shaping one stone, known as a core, by striking it
with another stone. As hunter-gatherers hammered the core into shape, chips and
flakes of various sizes fell away and were typically discarded as waste.  Professor Adler can't say for certain which
hominid species crafted the tools at Nori Geghi 1, because the fossil record
for this time period is not yet complete.

 

"This time period is very murky in terms of
evolution and who's making what," Professor Adler says. "While there
are a lot artifacts, there aren't that many fossils around, and most of them
aren't not dated particularly well."

 

One possibility is that the manufacturers were Homo
heidelbergensis,a shared ancestor of H. 
sapiens and Neanderthals.

 

Anthropologists believe that H. heidelbergensis lived
about 500,000 years ago; that those living in Europe are thought to have
evolved into Neanderthals while those living in Africa evolved into H.  sapiens. But the precise evolutionary
pathways remain murky, which means that the toolmakers at Nori Geghi 1 could
also have been some transitional species somewhere between H. heidelbergensis
and Neanderthals.

 

Gaps in the archeological record are particularly
pronounced in Europe, where erosion frequently caused various layers of earth
to mix in ways that make it difficult to date fossils and artifacts, Adler
explains.

 

Nevertheless, Adler and his team have been able to
date the artifacts found at Nori Geghi 1 with a surprising degree of precision.

 

Nori Geghi 1 is situated along the a gorge carved by
the Hrazdan River, which cut through basaltic lava flows from volcanoes in the
western part of the Gegham range.

 

"What's nice about this site is that it is capped
by lava which we can date [to 197,000-years- old], it's underlain by a lava
that we can date [to 441,000-years-old], and there's volcanic ash that we can
date [to 308,000-years-old], so we have a lovely dating package," Adler
explains.

 

Adler was able to pinpoint those dates within a margin
of error of just 7,000 years, a level of precision that is almost unheard of
for this time period, says Harvard anthropologist Christian Tryon, who was not
involved in the Nori Geghi 1 excavation. 
"The most striking thing about [Adler's research] : is that the
quality of the excavation and the quality of the dating of the site is some of
the best that I have seen in a decade," Professor Tryon says. "For
those of us that work in deep time : 10,000 years is considered a tight and
narrow age range."

 

In his own work in Africa, Tryon often has to rely on
a window of up to 300,000 years when dating artifacts and fossils.

 

This time capsule that has been trapped between those
two lava flows for thousands of years has also yielded some information about
how hunter-gatherers might have viewed the two technologies.

 

Some anthropologists have categorized Levallois
technology as more complex than the biface technique. But Adler found both
biface and Levallois tools side by side within the same layers of earth,
suggesting that whoever these toolmakers were, they seem to have used both
techniques simultaneously.

 

"I wouldn't consider this some sort of superior
technology and the biface as being primitive," Adler says. "What I
think it reflects is a new way for people to solve the same old problem of how
do you get your food and make your way in the world."