Stone tools 'demand new American story'
By Paul Rincon and Jonathan Amos
For The BBC
24 March 2011
The long-held theory of how humans first populated the Americas
may have been well and truly broken. Archaeologists have unearthed thousands of
stone tools that predate the technology widely assumed to have been carried by
the first settlers. The discoveries in Texas are seen as compelling evidence
that the so-called Clovis culture does not represent America's original
immigrants.
Details of the 15,500-year-old finds are reported in Science
magazine. A number of digs across the Americas in recent decades had already
hinted that the "Clovis first" model was in serious trouble. But the
huge collection of well-dated tools excavated from a creek bed 60km (40 miles)
northwest of Austin mean the theory is now dead, argue the Science authors. "This
is almost like a baseball bat to the side of the head of the archaeological
community to wake up and say, 'hey, there are pre-Clovis people here, that we
have to stop quibbling and we need to develop a new model for peopling of the
Americas'," Michael Waters, a Texas A&M University anthropologist,
told reporters.
For 80 years, it has been argued that the Clovis culture was
the first to sweep into the New World. These people were defined by their highly efficient stone-tool
technology. Their arrow heads and spear points were formidable hunting weapons
and were used to bring down the massive beasts of the Ice Age, such as mammoth,
mastodon and bison. The hunter gatherers associated with this technology were
thought to have crossed from Siberia into Alaska via a land bridge that became
exposed when sea levels dropped. Evidence indicates this occurred as far back
as about 13,500 years. But an increasing number of archaeologists have argued
there was likely to have been an earlier occupation based on the stone tools
that began turning up at dig sites with claimed dates of more than 15,000
years. Dr Waters and colleagues say this position is now undeniable in the
light of the new artefacts to emerge from the Debra L Friedkin excavation. These
objects comprise 15,528 items in total - a variety of chert blades, bladelets,
chisels, and abundant flakes produced when making or repairing stone tools.
The collection was found directly below sediment containing
classic Clovis implements. The dating - which relied on a technique known as
optically stimulated luminescence (OSL) that can tell how long minerals have
been buried - is robust, says the team. And, they add, the observed sequence is
also reliable; the sediments have not been mixed up after the tools were
dropped. "The sediments were very rigid in the fact that they were clay,
which worked to our advantage," explained Lee Nordt from Baylor University.
"If you go to many other sites, they are loamy or sandy in texture, and
they are mixed very rapidly by burrowing from animals or maybe from plant
roots, etc."
The newly discovered tools are small, and the researchers
propose that they were designed for a mobile toolkit - something that could be
easily packed up and moved to a new location. Although clearly different from
Clovis tools, they share some similarities and the researchers suggest Clovis
technology may even have been derived from the capabilities displayed in the
earlier objects. The Debra L Friedkin site lies just outside Austin "The
Debra L Friedkin site demonstrates that people were in the Americas at least
2,500 years before Clovis," said Dr Waters. "The discovery provides
ample time for Clovis to develop. People could experiment with stone and invent
the weapons and tools that would potentially become recognizable as Clovis. In
other words, [these tools represent] the type of assemblage from which Clovis
could emerge." But anthropologist Tom Dillehay, who was not involved with
the latest study, commented: "The 'Clovis first' paradigm died years ago.
There are many other accepted pre-Clovis candidates throughout the Americas
now." Professor Dillehay, from Vanderbilt University in Tennessee, told
BBC News: "If you look at the prose of this paper, it bothers me a little
bit because it's as if they are reconstituting the Clovis-Pre-Clovis debate and
saying, 'Here's the site that kills it'." He commended the researchers on
their well-presented data and "tight discussion". But he said that
the OSL technique was less reliable than radiocarbon dating, which has been
applied to other early American sites. And assigning the artefacts to Clovis
and pre-Clovis technologies was not straightforward because the site lacked the
projectile points required to reliably distinguish between the two. Clovis
projectile points are unmistakeable.
In addition, said the Vanderbilt anthropology professor, the
tools come from a floodplain deposit that is just 6-7cm thick. This, he said,
was "potentially problematic" because of the possibility that artefacts
were transported around by water. Professor Gary Haynes, from the University of
Nevada in Reno, US, praised the "good work" by the research team. But
he said it was plausible that natural processes could have caused some stone tools
to migrate downwards in the clay - giving the impression of a pre-Clovis layer.
[I’ve come across this idea a few times – that the generally
accepted argument for the ‘Clovis’ people populating the America’s – was just
too simplistic and far too late. Although the find of early tools and other
items are not beyond question it does appear from an increasing number of
pre-Clovis dig sites that humans reached and colonised America early than is
generally accepted. Cool when our ideas change about things in our deep past
isn’t it?]
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