viernes, 13 de enero de 2017

Archaeological Find Puts Humans in North America 10,000 Years Earlier Than Thought

A figure from the researchers’ paper shows where the marked bone would have been in the horse’s jaw. Radiocarbon dating puts the bone at 24,033 to 23,314 years before present. Photo by Bourgeon et al.
New evidence suggests humans lived in a Yukon cave during the last ice age 24,000 years ago.

About 24,000 years ago, when much of North America was buried under the ice of the Last Glacial Maximum, a few hunters took shelter in a small cave above the Bluefish River in what is now northwestern Yukon. The hunters had killed a Yukon horse and were butchering it using super-sharp stone shards called microblades. As they sliced out the horse’s meaty tongue, the microblades left distinctive cuts in its jawbone. Millennia later archaeologist and doctoral candidate Lauriane Bourgeon spotted those marks through her microscope at the University of Montreal, and added the fragment of ancient jawbone to her small selection of samples for radiocarbon dating.

The bones came from excavations led by archaeologist Jacques Cinq-Mars between 1977 and 1987, and have been in storage at the Canadian Museum of History in Gatineau, Quebec. At the time, Cinq-Mars and his team concluded that the Bluefish Caves showed evidence of occasional human use as much as 30,000 years ago. That is so much older than anything else found in the Americas that Cinq-Mars’s conclusions were widely disputed, and the three small caves largely left out of discussions about the peopling of the Americas.

The idea of researching such a controversial site appealed to Bourgeon: “Alaska, Yukon, bone accumulations, caves, the first peopling. …That was it. That was the Spell of the Yukon!” she said by email.

Bourgeon sent six pieces of bone that showed evidence of stone tool cuts to a lab in Oxford, England, for radiocarbon dating. The youngest, it turned out, was a 12,000-year-old caribou bone. The most ancient: the 24,000-year-old horse jawbone.

The finding makes the Bluefish Caves the oldest archaeological site in North America by a margin of almost 10,000 years—and confirms much of Cinq-Mars’s work.

Previously, the oldest accepted human occupations were three sites in Alaska and one just over the border in Yukon, all dating to about 14,000 years ago. [...] Hakai Magazine

Related post 

Actualización: Los primeros humanos llegaron a América 10.000 años antes

El momento de la primera entrada de seres humanos en América del Norte a través del estrecho de Bering se ha retrasado en nada menos que 10.000 años.

Esto ha sido demostrado sin lugar a dudas por Ariane Burke, profesora del Departamento de Antropología de la Universidad de Montreal y su estudiante de doctorado Lauriane Bourgeon, con la contribución del Dr. Thomas Higham, Subdirector de la Unidad de Aceleradores de Radiocarbonos de la Universidad de Oxford.

La fecha de liquidación más temprana de América del Norte, hasta ahora estimada en 14.000 años antes del presente, según los sitios arqueológicos más antiguos, ahora se estima en 24.000 años, a la altura de la última edad glacial o último máximo glacial.

Los investigadores hicieron su descubrimiento usando artefactos de las Cuevas Bluefish, ubicadas a orillas del río Bluefish en el norte de Yukon, cerca de la frontera de Alaska. El sitio fue excavado por el arqueólogo Jacques Cinq-Mars entre 1977 y 1987. Basándose en la datación por radiocarbono de los huesos de los animales, el investigador hizo la audaz hipótesis de que el asentamiento humano en la región databa de hace 30.000.

En ausencia de otros sitios de edad similar, la hipótesis de Cinq-Mars permaneció muy controvertida en la comunidad científica. Por otra parte, no había pruebas de que la presencia de caballo, mamut, bisonte y los huesos de caribú en las Cuevas Bluefish se debió a la actividad humana...

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Actualización: Los primeros humanos llegaron a América 10.000 años antes