Mexico City, Jul 22 (efe-epa).- Archaeological research in a cave in northern Mexico has uncovered evidence that humans inhabited the zone 30,000 years ago, suggesting that man came to North America 15,000 years earlier than thought, according to an article Nature magazine published on Wednesday.
The publication says that since 2012 a team from the Autonomous University of Zacatecas has been excavating in the Chiquihuite cave in the Astillero Mountains, where they have found almost 2,000 stone tools, of which 239 were resting in layers of gravel dating to between 25,000 and 32,000 years ago.
The “general opinion” up until this discovery has been that the first people arrived in the Americas from Asia about 15,000-16,000 years ago.
This figure is based on finds at the Monte Verde II site in Chile, which have been dated to 14,000 years ago.
According to Nature, the head of the new investigation, Ciprian Ardelean, believes that the cave was visited “occasionally,” given that only relatively few ancient tools have been found there.
He told the magazine that ancient hunter-gatherers possibly used it as a shelter for a few decades, during particularly severe winters, noting that 26,000 years ago, during the last Ice Age, North America had been a “dangerous” area.
According to the investigators, Chiquihuite cave is quite isolated and could have provided shelter for people, protecting them from snowstorms, for instance.
The investigation has garnered some controversy, however.
A team of geneticists headed by Eske Willerslev at the University of Copenhagen looked for ancient human DNA in the dirt and gravel layers covering the bottom of the cave but found nothing.
In addition, Nature compared the investigation’s results with those of François Lanoë, an archaeologist and anthropologist at the University of Arizona who warned that the tools found in the cave could have been displaced downwards into deeper layers of gravel by geological activity.”
Meanwhile, Ardelean admitted that some of the tools could have been shifted to lower layers, although he said that the 239 oldest stone implements were found under an impenetrable layer of mud that formed during the height of the last Ice Age.