Did humans migrate to America 100,000 years earlier than historians suggest? This discovery from 2017 put a large question mark on the entire prehistory of the Americas.
In 2017, American archaeologists reported a sensational find that points to the possible presence of humans in America as early as 130,000 years ago. These were the results of radiometric dating of the bones of a mastodon with traces of targeted processing, found in southern California.
Massive stones were found near the bones, presumably used as anvils and hammers for splitting bones and extracting bone marrow. Judging by the nature of the chips, the bones were processed soon after the death of the animal.
Until then, the oldest reliably dated human sites in America were no more than 14-15 thousand years old. Thus, we are talking about a possible revision of the prevailing ideas about the history of the settlement of America. Unfortunately, apart from the alleged anvils and hammers, no other stone tools were found nearby.
History in Question: Did Humans Live in America 100,000 Years Earlier Than We Know?
In recent decades, archaeologists and geneticists have jointly reconstructed the history of the settlement of America in some detail. According to the current model, the ancestors of Native Americans settled the northeastern tip of Asia, Beringia, and Alaska about 26-18 thousand years ago.
Somewhat later, 15-14 thousand years ago, when passages began to open in the ice sheet that covered present-day Canada, the ancient inhabitants of Alaska quickly settled in North and South America.
At the same time, there are periodic reports of more ancient traces of human presence in America. However, a careful re-examination of these findings has shown that they are all dubious at best. (see, for example, S. A. Morse et al., 2010. Techniques for verifying human footprints: reappraisal of pre-Clovis footprints in Central Mexico).
As a result, experts came to the conclusion that today there is no compelling reason to assume the presence of people in America (south of Alaska) earlier than 15 thousand years ago.
The sensational discovery of American archaeologists, which they reported in 2017 in the pages of the journal Nature, may force a revision of this established point of view – of course, if further research does not reveal errors in the dating and interpretations given in the article.
What the authors certainly cannot be blamed for is that they were too hasty with conclusions. The mastodon bones and alleged stone tools (anvils and hammers) discussed in the article were excavated in southern California, near San Diego, back in 1992-1993. The site was named the Cerutti Mastodon site in honor of the paleontologist Richard Cerutti of the Museum of Natural History in San Diego who discovered it.
Scattered bones belonging to a young male American mastodon, Mammut americanum, were distributed over an area of 50 square meters within a thin (20–30 cm) layer of sandy silt that forms part of a 12-meter stratum of Pleistocene river sediments.
One tusk of the mastodon lay horizontally, like the other bones, but the other was stuck into the rock vertically, piercing the underlying layers. The authors believe that prehistoric people could have stuck the tusk into the river sediment, although it is hardly possible to prove this.
The bones show numerous signs of targeted processing. Apparently, they were chopped to extract the bone marrow. It is important that both massive femurs (and, for some reason, one upper molar) were split, while the more fragile elements of the skeleton (ribs, vertebrae) remained intact.
The bone fragments are concentrated in two clusters, located about two meters from each other. In addition to bones, each cluster contains one large andesite cobblestone, presumably serving as an anvil. There were also weighty hammer stones and accidentally splintered fragments, exactly matching the corresponding chips on hammers and anvils.
Judging by the nature of the chips, the bones were processed while still fresh, soon after the death of the mastodon. To be convinced of this, the authors experimented with the bones of modern elephants and cows, splitting them with blows of massive stones. Both fragments of bones and marks on hammers and anvils in these experiments turned out to be similar to those found in the archaeological site.
According to the authors, it is unlikely that the slowly flowing river that formed this and the adjacent layers of muddy deposits could itself bring massive stones – supposed anvils and hammers – and lay them among the bones of a mastodon who died here.
Moreover, in other places, farther from the bones, there are no large stones in this layer. Bones of mammals (for example, dire wolf and horse) are found in adjacent layers, but they are not associated with stones and do not bear traces of purposeful splitting.
But, of course, the most important thing in the study is dating. No one would have been surprised by such a find, if it were, say, 13,000 years old, when in North America there were definitely people who hunted mastodons and mammoths at this time.
The supplementary materials to the article under discussion describe in detail how, for various reasons, it was not possible for a long time to obtain a reliable age, either for the bones of the Cerutti mastodon or for the host rock.
For example, all attempts to perform radiocarbon analysis of bones have ended in nothing, because collagen is not preserved in the bones. Considerable efforts spent on attempts to determine the age of the rock using optically stimulated luminescence dating gave little more: it turned out that the age of the rock is most likely more than 60-70 thousand years and is outside the interval to which we apply this dating method.
Finally, the authors were able to obtain the dating of bones, which seem more or less reliable, using Uranium-thorium dating). However, here it was not without pitfalls.
Ideally, this method requires that uranium, the concentration of which in the bones of modern animals does not exceed 0.05 μg / g, is not introduced into the bone after death, or it is necessary to somehow determine the scale and dynamics of the input.
Uranium was clearly introduced into the bones of the mastodon Cerutti in large quantities because its concentration there averages 160 μg / g. The authors developed a complex model describing the expected dynamics of uranium intake into the bones of the mastodon after their burial in river sediments and based on the ratios of uranium isotopes in bones and in the environment, as well as on the results of laboratory experiments in which the interaction of uranium compounds with bones was studied.
Based on this model, the uranium-thorium age of the mastodon Cerutti was calculated. It was 130.7 ± 9.4 thousand years, which roughly corresponds to the previous (Riess-Wurm) interglacial. Without corrections associated with modeling, the ages were obtained in the range from 100 to 125 thousand years.
The research was certainly met with a lot of skepticism. Sapiens at that time were found only in Africa, and, perhaps, a little in the Middle East. Who were the hypothetical ancient Californians? Denisovites? Erectus? How did they get to America? Why is there no trace of the presence of such ancient populations in Northeast Asia?
The complete absence of real, purposefully made stone tools, not to mention human bones, does not add credibility to the conclusions of the authors. By the way, on the bones of the mastodon Cerutti, there are no traces of scraping meat from bones, usual for the Paleolithic. In addition, everyone knows that sensational reports about abnormally ancient traces of the presence of people in America have appeared more than once and have always been refuted in the end.
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• Barras, C. (2017, April 26). First Americans may have been Neanderthals 130,000 years ago.
• Cerutti Mastodon site. (2020, October 21).
• Greshko, M. (2020, May 07). Humans in California 130,000 Years Ago? Get the Facts.
• Holen, S., Deméré, T., Fisher, D., Fullagar, R., Paces, J., Jefferson, G., . . . Holen, K. (2017, April 27). A 130,000-year-old archaeological site in southern California, USA.
• Morse, S., Bennett, M., Gonzalez, S., & Huddart, D. (2010, July 13). Techniques for verifying human footprints: Reappraisal of pre-Clovis footprints in Central Mexico.
• Yong, E. (2017, April 27). A New Study Says Humans Were in America 130,000 Years Ago.