The timing of humans’ first arrival in the Americas south of glacial ice remains a topic of heated debate in archaeological circles. In the summer of 2020, a team working in Mexico claimed discovery of evidence for human occupation of a remote highland cave beginning over 30,000 years ago. Because this announcement was made in the journal Nature, it was disseminated broadly and thus rapidly became accepted doctrine in the public mind before it had been vetted by the scientific community. Today in the journal Paleoamerica, which focuses on first Americans issues, a group of 20 researchers from the US and Mexico, including MSU Anthropology Assistant Professor Kurt Rademaker, challenge the Chiquihuite claim on the basis of their review of the evidence.
They found that the Chiquihuite authors failed to consider the alternative hypothesis that the objects were the result of natural processes. Chatters et al. examined both hypotheses (human vs. natural agency) and determined that the Chiquihuite assemblage is probably composed of limestone broken through natural processes, or “geofacts.” Relevant data included fracture mechanics, where the stone pieces more closely match geofact expectations and the geochemical analyses which failed to distinguish purported artifacts from naturally occurring rocks. Thus, Chiquihuite Cave does not represent very early human occupations in the Americas, and does not support human arrival before the Last Glacial Maximum.
Read the two papers here:
Critique of Ardelean et al.
Critique of Valdivia and Higham