Tuesday, October 4, 2016

Campsites In Argentina Place Humans There 14,000 Years Ago

Campsite Places Humans in Argentina 14,000 Years Ago

Excavations at the site Arroyo Seco 2 include stone tools and evidence that humans 

were hunting giant sloths, giant armadillos and extinct horse species

Stone Tools
(PLOS One)

For decades, archaeologists believed that the Clovis culture, named for its distinctive blades, was the first people to cross the Bering Land Bridge and colonize the Americas. But a decade of evidence has quietly chiseled away at the notion that the Clovis were the first across. In fact, more and more evidence shows that earlier humans likely entered the western hemisphere by taking small boats down the coast. Evidence shows humans made it to the tip of Argentina 15,000 years ago and pre-Clovis people may have roamed the area as early as 18,000 years ago.
A new study of site in Argentina lends even more credence to the idea that people made it to South America millennia earlier than traditionally thought. Annalee Newitz at Ars Technica reports that archaeologists at a dig site in the Argentine pampas called Arroyo Seco 2 located outside the city of Tres Arroyos have uncovered evidence that humans were hunting and processing now-extinct animals at the site 14,000 years ago.
The researchers, led by Gustavo Politis from the Universidad Nacional del Centro de la Provincia de Buenos Aires, found at least 50 tools made of chert and quartzite at the site that show signs of wear and tear consistent with scraping animal hides. The tools are also made of materials found dozens of miles away from the camp, meaning they were likely transported there by humans.
The site, a grassy knoll overlooking a deep lake, also contains thousands of animal bones which were carbon dated between 14,064 and 13,068. While there are natural “traps” that tend to collect animal bones over the centuries, Newitz reports that those are typically found in holes or natural depressions. The fact that so many bones are found on top of a hill points to human involvement.
The bones themselves also showed signs of human processing. According to a press release, microscopic examination shows that many of the specimens contain fractures consistent with the use of stone tools. Most of the bones also lack the type of puncture marks left by the teeth of carnivores.
According to the paper, which is published in the journal PLOS Onethe researchers found about 100,000 bones at the site, 6,200 of which have been identified as coming from 40 different taxa of animals. This includes many extinct species including two species of horse, giant armadillos, giant ground sloths, camels and others.
Most of the large animal remains, like the giant sloths', also lack a skull and pelvis, indicating that the hunters likely did some butchering at the kill site before bringing the animal into their camp. “Given the body mass of this species (between 4 and 5 tons), it would have been extremely difficult to transport the entire carcass and even challenging to transport complete hindquarters weighing between 600 and 750 kg, and forequarters weighing between 250 and 300 kg,” the researcher write in their paper.
Though there are dozens of human remains at the site, they are millennia younger than the animal remains, from a period 9,000 years ago. Researchers did not find a smoking gun at the dig site, like associated human remains or cut marks on the bones, but the evidence lines points to the area being a seasonal hunting camp for pre-Clovis people.
As archaeologist Tom Dillehay, who identified artifacts from a 14,000-year-old human settlement in Chile back in the late 1970s, Arroyo Seco 2's findings offers further evidence that humans were in southern South America at this time.
“While the characteristics of some of these archaeological materials could be explained without human intervention, the combination of evidence strongly suggests human involvement. Humans' arrival in southern South America 14,000 years ago may represent the last step in the expansion of Homo sapiens throughout the world and the final continental colonization,” the researchers say in the press release.
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