Archaeologists are turning to the Chicxulub crater and using prehistoric teeth to track ancient humans.
First, University of Florida's Ashley Sharpe made a map to determine the birthplaces of ancient animals and people in Central America. This was done using lead isotope values from rocks from the Chicxulub crater, the site where the asteroid that wiped out the dinosaurs hit Earth fell, as well as locations in Honduras, Guatemala and Belize. This map is important because it will be used to match lead found within prehistoric teeth.
"If I find an ancient Maya individual buried on the Yucatan in Mexico, I can do a chemical analysis of the lead in their teeth and discover a very different story," said Sharpe, adding the discovery can change how archaeologists view everything.
Pinpointing locations of birth and death will help archaeologists in tracking the movement of prehistoric Mayans, which can potentially help in solving the mysteries of their civilization's origin and eventual demise. Sharpe and colleagues published their work in the journal PLOS One.
Teeth Tell A Lot About A Person
When tooth enamel is formed in childhood, it absorbs elements from an individual's local environment, including the dust they breathe. This means that the mineral component of teeth will have an isotopic composition that is associated with the area or environment in which that person spent their formative years. On the other hand, bone changes every few years. When a person is buried, their bones start soaking up materials around them like a sponge as they decompose.
To extract the lead content in teeth, these are ground up before particles are inserted into an inductively coupled plasma mass spectrometer. To separate the lead, the machine heats up to temperatures hotter than the Earth's sun.
Turning to teeth to trace an individual's movement can offer clues regarding ancient activities like slavery practices and marriage alliances. Getting these kinds of information can help archaeologists in determining which villages were at odds and which ones were allied with each other, as well as how Mayans communicated and moved from city to city.
Today, however, pollution complicates lead analysis. Because everyone breathes similar levels of pollution, lead content in teeth may be contaminated, making it difficult to differentiate between remains from, say, a native Floridian who lived 1,000 years ago and someone who lives on the other end of the United States.
Lead Analysis Today
Utilizing lead analysis to find birthplaces is a practice forensic anthropologists use to find more information on homicide victims that have not been identified. By narrowing down search areas for police investigations to a specific state, region or country, it helps speed up victim identification, which can also speed up the resolution of a case.
In the past, lead analysis has been used to track Indus Valley Civilization's ancient humans.