April 22, 2013

OSL dating: Brazilian site is 22,000 years ago

Toca da Tira Peia is the new name of American prehistory, providing an OSL date for the layer of scattered stone tools of c. 22,000 years BP. Located near the also controversial Pedra Furada site, the date seems to give some support to those who dare to think outside the box on the early peopling of America.

Christelle Lahaye et al., Human occupation in South America by 20,000 BC: the Toca da Tira Peia site, Piauí, Brazil. Science 2013. Pay per view LINK [doi:10.1016/j.jas.2013.02.019]

Abstract

When and how did the first human beings settle in the American continent? Numerous data, from archaeological researches as well as from palaeogenetics, anthropological and environmental studies, have led to partially contradictory interpretations in recent years, often because of the lack of a reliable chronological framework. The present study contributes to the establishment of such a framework using luminescence techniques to date a Brazilian archaeological site, the Toca da Tira Peia. It constitutes an exemplary case study: all our observations and measurements tend to prove the good integrity of the site and the anthropological nature of the artifacts and we are confident in the accuracy of the luminescence dating results. All these points underline the importance of the Toca da Tira Peia. The results bring new pieces of evidence of a human presence in the north-east of Brazil as early as 20,000 BC. The Toca da Tira Peia thus contributes to the rewriting of the history of the peopling of the American continent.

There are slightly older sites in North America, however they are all surrounded into some degree of controversy: Topper in South Carolina is dated to c. 23,000 cal-BP (C14) while some sites in Alberta, located in the Mackenzie "ice-free corridor" have also dates under the LGM layer (i.e. > 21 Ka BP).

There's actually nothing impossible about such early dates in my understanding.

See also:

3 comments:

  1. I'm with Andrew, the strongest argument being:

    "There is no historical precedent for modern humans moving into virgin territory on a sustained basis for thousands of year without expanding exponentially and leaving an obvious sign of their presence."

    New Zealand was settled by a few canoe loads of neolithic people. Yet within a century it was fully inhabited with the moas extinct. After that, settlements were fortified and left strong archeological footprints.

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    1. As I told him, the evidence in East Asia is also very sketchy especially for the early period and much of it is also under question marks (Liujiang, Zhirendong, Callao, etc.) as is the possible settlement of Australia prior to 50 Ka BP. By comparison this dating seems very methodical, assuming that the artifacts are real and not naturally occurring rocks.

      The example of New Zealand is very different because the evidence is much more recent, i.e. better preserved, easily dated with radiocarbon and other methods and shallower in the geology (easier to locate). Also Neolithic peoples are always more numerous, settling the countries in a much denser way. I think that the proper comparison areas are Paleolithic Asia and Sahul, or even Africa, where new evidence, often with associated question marks, is being found almost every year. I have no reason to think that America is as well combed as Europe nor that Neolithic contexts like the one you mention are comparable in any way.

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  2. Fascinating. Recently I attended a presentation on the re-discovery of a Sauk village near present day Quad Cities. The research into when the Americas were populated is extremely exciting to me. I appreciate this article and others on the subject. Keep up the great work.

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