Somerville et al. (2021) recently raise the possibility in Latin American Antiquity of 30k year old archaeological material at Coxcatlan cave in the Tehuacan Valley of Mexico. This one isn’t making much of a splash in the media (so far), and I suspect that is because it is actually cautious and very appropriately presented. At the time of this writing, it has a modest 612 views and 127 downloads. There are 18 news stories, but the big media players are notably absent, and the headlines mostly replicate the appropriately tentative language of the University’s own press release. The fact that the article is in Latin American Antiquity and not in Nature or Science could also contribute to the lack of visibility (thanks to Julien-Riel Salvatore for that comment), but these factors are probably related.
The authors don’t actually claim that they have found 30k year old archaeological material in Coxcatlan cave. They establish with new AMS dates that some of the faunal material originally excavated from the lower levels by MacNeish is 30k years old, and that it could be evidence of human activity, if it is indeed associated with archaeological material. They propose a plan to determine whether it is associated with archaeological material, which I hope they carry out.
They appropriately note that “In consideration of the antiquity of the new AMS radiocarbon ages, the possibility that [artifacts found in the level] were products of natural forces and not of human labor must be considered.” It seems they either don’t have direct access to that lithic material, or have not yet looked at it to see whether it is convincingly human, but they propose to do so. They do say that the fact that the experience of the team that first identified it speaks in its favour.
They discuss whether the faunal remains in those lower levels are more consistent with the Last Glacial Maximum or with the Pleistocene/Holocene boundary. Yes, there are more arid seeking species than you would expect for the Holocene, but then again, this is also apparently true at other nearby sites that are about 12k years old. On the other hand, there are no deer remains in the deepest layers, and those become important in the later, more obviously Holocene layers.
They do note that there are recent claims of material of the same age in the same region, and other claims in other parts of the Americas, but that these are controversial and not well accepted. They could have gone in to a bit more detail about why they are controversial, especially in the case of Chiquihuite.
In other words, Sommerville et al. not only acknowledge, but discuss the main usual points of disagreement about claims of very early archaeological material in the Americas. Is the faunal material associated with other evidence of human activity such as lithic remains? Possibly, but they can’t confirm because they need to examine the lithics. Is the fauna representative of the claimed period, and not a later period? Possibly, but the pattern is ambivalent.
Somerville, the lead author, has a companion piece on the CambridgeCore blog, which is ever so slightly bolder in its presentation, and which, reading between the lines, reveals his favoured interpretation, or perhaps just his fond hope for the future, but that is far from being a scholarly sin.
As far as papers on surprisingly early archaeological claims in the Americas go, this is a good one, not because it presents a paradigm shifting find, but because it is carefully written and argued, and transparently supported. It doesn’t over-reach its data, but it does tickle the imagination. The next one could be even better, especially once the lithics from the original excavation have been re-examined.
This is the kind of paper that should get attention from high profile journals and generate headlines. Unfortunately, these are not the papers that usually do.
Reference
Somerville A, I Casar, J Arroyo-Cabrales 2021. New AMS Radiocarbon Ages from the Preceramic Levels of Coxcatlan Cave, Puebla, Mexico: A Pleistocene Occupation of the Tehuacan Valley? Latin American Antiquity, 1-15. doi:10.1017/laq.2021.26
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