How technology helped archaeologists dig deeper in ancient cities

Joseph Jones, an anthropologist at the College of William & Mary and one of the site’s investigators, told me the science had matured even while his team was still digging. At the start of their excavation, they analyzed the skeletal remains using the same techniques archaeologists had used for nearly a century, measuring the size of the bones and examining the damage to them to infer details about the people’s lives. Today, however, the team uses modern techniques that previous generations of researchers only dreamed of: using lasers to slice up micro-thin pieces of tooth enamel so that trapped isotopes could be analyzed; sequence ancient DNA to link people who died centuries ago to their descendants.

The African Cemetery was also discovered at a time of cultural discovery. Historians investigated the role slaves played in building northern cities, while black scholars like Henry Louis Gates Jr. and writers like Toni Morrison centered the roles of African Americans in U.S. history. .

Using remote sensing technologies like lidar, researchers can discover an entire urban network, giving us a better picture of what it would have been like to walk around neighborhoods and peek into stores.

Scientific analysis of the site added compelling data to these social movements and changed the way many Americans viewed the founding of their nation. He revealed that slaves from Africa built many cities that Americans still live in today – north and south. And it showed how we went from a nomadic species that traveled in small groups to sharing very tight habitats with millions of other people.

The African Burial Ground project was among the first to use a new constellation of “bioarchaeology” tools that go far beyond traditional picks and brushes. But that was only the first step in a much larger archaeological revolution that brought together scientists and humanities to generate data about our ancestors. Today, researchers complement bioarchaeology with 3D photography, lidar, satellite imagery, and more.

Sometimes referred to as “data archeology,” this type of high-tech exploration is well suited to the study of urban history. Using remote sensing technologies like lidar, researchers can discover an entire urban network, giving us a better picture of what it would have been like to walk around neighborhoods and peek into stores. This type of data enables precise digital recreations, meaning historians can turn a remote, inaccessible site into something anyone can visit online.

This data is also democratizing history: researchers can now examine hundreds, if not thousands of remains and process large datasets to better understand the experiences of ordinary people – not just the lucky few who owned land, registered their findings. names on monuments or held public office.

Say tooth

Data archeology is particularly useful for historians who study cities, as urban locations often contain immigrant stories that might otherwise be difficult to trace. Bioarchaeologist Michael Blakey, who has led the African Burial Ground project since the early 1990s, said his team would never have known where the people at the cemetery came from had they not been able to do several types of chemical analyzes on their tooth enamel. Because this enamel is made up of layers as humans mature, chemists can study a cross section of the tooth and learn what substances people were exposed to as children. It’s a bit like analyzing tree rings, where each layer of enamel represents a period in a person’s life.


Immediately, they found a sharp dividing line between people born in Africa and people born in the Americas: lead. Although African civilizations worked with a range of metals, lead was used almost exclusively by Europeans, for things like pipes and pewter dishes. Anyone who had lead in childhood tooth enamel was almost certainly born locally.

As science developed, Blakey’s group also used a technique called strontium isotope analysis to learn more about where people came from. When people eat and drink in a specific area for a long time, their teeth absorb a small amount of strontium, an element that escapes from rocky soil in food and drinking water. Strontium from older land masses has a slightly different chemical signature than strontium from more recent ones, so examining isotopes in people’s tooth enamel allows researchers to determine roughly where they lived throughout. their life.

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