Stone tools show earlier human arrival in North America
July 23, 2020
A study published on Wednesday revealed that North America was likely inhabited by humans as early as 26,500 years ago, much earlier than most scientists accept.
The discovery came from the analysis of tools excavated from a cave in central Mexico which now provide strong evidence humans were living in North America some 15,000 years earlier than previously thought.
Published in the journal Nature, the study focused on artifacts — including 1,900 stone implements — found in the high-altitude Chiquihuite Cave.
Imported tools
The stone tools, a unique find in the Americas, revealed a "mature technology," which the study's authors believe was brought from elsewhere.
"Our results provide new evidence for the antiquity of humans in the Americas," Ciprian Ardelean, an archaeologist at the Universidad Autonoma de Zacatecas and lead author of the study said.
Ardelean said that radiocarbon dating results put a few of the artifacts within an age range of 33,000 to 31,000 years old, although scientists are still trying to verify this.
No traces of human bones or DNA were found at the site. "It is likely that humans used this site on a relatively constant basis, perhaps in recurrent seasonal episodes part of larger migratory cycles," the study concluded.
Archaeologists take sides
Until recently, the widely accepted theory of human arrival in the Americas stipulates that early ancestors crossed a land bridge from present-day Russia to Alaska some 13,500 years ago and moved south through a corridor between two massive ice sheets.
The theory is fiercely debated among experts and the new study will likely be heavily contested as well.
"That happens every time that anybody finds sites older than 16,000 years — the first reaction is denial or hard acceptance," said Ardelean, who first excavated the cave in 2012 but did not discover the oldest items until 2017.
Anthropology professor Tom Dillehay of Vanderbilt University in Nashville, Tennessee, who was not involved in the cave study, said the proposed dates may ultimately be considered valid if they can stand up to further scrutiny.
He doesn't question that some of the artifacts are likely man-made, but said he'd like to see other evidence of human occupation of the cave, like hearths, butchered bones and burned edible plant remains.
jcg/nm (AFP, AP)