Discovery in Mexican Cave May Drastically Change the Known Timeline of Humans' Arrival ... [View all]

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Discovery in Mexican Cave May Drastically Change the Known Timeline of Humans’ Arrival to the Americas

Surprisingly old stone points found in a Mexican cave are the latest intriguing discovery among many to raise questions about when humans really arrived in the Americas.

For most of the 20th century archaeologists generally agreed that humans who had crossed the Beringia land bridge from Siberia to North America only ventured further into the continent only when retreating ice sheets opened a migration corridor, about 13,000 years ago. But a few decades ago, researchers began discovering sites across the Americas that were older, pushing back the first Americans’ arrival by a few thousand years. Now, the authors of a new study at Mexico’s Chiquihuite cave suggest that human history in the Americas may be twice that long. Put forth by Ciprian Ardelean, an archaeologist at the Autonomous University of Zacatecas (Mexico), and his colleagues, the new paper suggests people were living in central Mexico at least 26,500 years ago.

Ardelean’s work was published in Nature and paired with another study that presented a broader look at 42 known early human sites across North America from the Bering Strait to Virginia. Data from those sites were used to model a much earlier peopling of the Americas, and help scientists reimagine not only when but how the first people reached and populated the New World. The model features a number of archaeological sites, including Chiquihuite cave, which are intriguing but controversial enough, as experts disagree whether the sites actually evidence human occupation.

Chiquihuite cave is perched high in the Astillero Mountains, 9000 feet above sea level and 3,280 feet higher than the valley below. Excavations there were launched when a 2012 test pit unearthed a few stone artifacts that suggested a human presence dating back to the Last Glacial Maximum between 18,000 and 26,000 years ago. More extensive excavations detailed in the new study were carried out in 2016 and 2017, unearthing some 1,900 stone points or possible tools used for cutting, chopping, scraping, or as weapons.

The artifacts were dated by 46 different radiocarbon samples of adjacent animal bones, charcoal, and sediment samples. To the team, they represent a previously unknown technological tradition of advanced flaking skills. More than 90 percent of the artifacts were of greenish or blackish stone, though those colors are less common locally, suggesting to the authors that they were singled out as desirable. The bulk of the material is from deposits dating to between 13,000 and 16,600 years ago, leading the scientists to hypothesize that the humans may have used the cave for more than 10,000 years.

https://www.smithsonianmag.com/science-nature/when-did-humans-reach-america-mexican-mountain-cave-artifacts-raise-new-questions-180975385/

A stone point from Chiquihuite cave (Ciprian Ardelean)