https://www.sciencenews.org/article/cave-mexico-stone-artifacts-humans-americas-early
Science News said:Humans may have arrived in North America way earlier than archaeologists thought.
Stone tools unearthed in a cave in Mexico indicate that humans could have lived in the area as early as about 33,000 years ago, researchers report online July 22 in Nature. That’s more than 10,000 years before humans are generally thought to have settled North America. This controversial discovery enters a new piece of evidence into the fierce debate about when and how the Americas were first populated.
“A paper like this one is really stirring up the pot,” says coauthor Eske Willerslev, an evolutionary biologist at the University of Cambridge. It “will no doubt get a lot of arguments going.”
For decades, archaeologists thought the Americas’ first residents were the Clovis people — big game hunters known for their well-crafted spearpoints who crossed a land bridge from Asia to Alaska about 13,000 years ago (SN: 8/8/18). Recent, well-accepted archaeological discoveries suggest that North America’s first settlers actually arrived a few thousand years before the rise of the Clovis culture, by about 16,000 years ago (SN: 10/24/18), says Vance Holliday, an archaeologist the University of Arizona in Tucson not involved in the new work.
If the new finds really are human tools, Holliday says, this would be the oldest evidence for a human-inhabited site anywhere in the Americas.
At Chiquihuite Cave in central Mexico, archaeologists unearthed what appear to be over 1,900 stone tools. Using radiocarbon dating to determine the ages of charcoal, bone and other detritus surrounding the artifacts, the researchers determined that more than 200 of the tools were embedded in a layer of earth as old as 33,150 to 31,400 years. Other artifacts were found in a layer as fresh as about 13,000 years old.
The tools, excavated from 2016 to 2017, do not resemble Clovis technology or any other stone tools found in the Americas, the researchers say. This haul “has a lot of small blades and small flakes that were used for cutting,” says archaeologist Ciprian Ardelean of the Autonomous University of Zacatecas in Mexico. His team also dug up squarish stone fragments that he suspects were used to make composite tools of some sort, assembled from pieces of rock stuck into wooden or bone shafts.
“People are going to disagree about whether this qualifies as evidence” of human activity, says Loren Davis, an archaeologist at Oregon State University in Corvallis not involved in the work. “These are rocks that were broken, but … people don’t have a monopoly on the physics involved with breaking rocks.” Davis says that a closer examination of the artifacts in person or via 3-D models could convince him that they are indeed relics of human craftsmanship.
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