Scientists have developed a new method that will help determine the region of vital origin of ancient people by analyzing the content of these substances in their tooth enamel.
Researchers at the University of Arkansas tested their method on remains from the mounds of the Caddo Indian sanctuary in southwestern Arkansas. The mandibles and skull bones they examined are 600-800 years old, but in the future, the method will allow the study of older remains.
Lead isotopes taken from teeth are compared with values obtained from teeth from animals of the same period, as well as from samples of geological rocks and soil. The work was published in the Journal of Archaeological Science.
Lead, toxic to living organisms, is deposited in the enamel of people and animals, creating a "signature" that can very accurately determine the area in which a living creature grew up. As the work showed, a comparative analysis of tooth enamel is most preferable, but comparison with geological rocks turned out to be of little information.
A serious snag in such studies is the modern anthropogenic lead pollution. If lead from gas, mines, or industrial sources contaminated the remains, isotope analysis will not be able to accurately show their origin. In addition, lead can be contained in the soil without being introduced into it by humans. To eliminate this influence, the authors of the article applied three different methods for assessing pollution and developed recommendations for future research on this topic.
Pilot research provided answers to questions relevant to the history and culture of the Caddo Indians. Their ceremonial mounds at the Crenshaw site, Red River, contain remains that have not been sufficiently identified to date. Previous research has provided conflicting interpretations of whether the remains were aliens killed by the Indians, or their own ancestors. Clarity in this matter would shed light on the rituals and way of life of this tribe in antiquity.
A study using the new method showed that the teeth of the five people the scientists analyzed contained the same isotopes as the teeth of animals from several excavations in the area. These isotopic signatures were very different from the isotopes of humans and animals from other regions.
Scientists explain that this is a big step towards the creation of a universal way to determine the region of origin of ancient people. Such a method would complement the arsenal of working methods of historians, archaeologists and anthropologists, providing science with a wealth of new data.