Archaeologists studying the history of Native Americans before Europeans set foot on American soil are leveraging advanced technology to pinpoint hidden markers of the past.
"Across the East Coast of the United States, some of the most visible forms for pre-contact Native American material culture can be found in the form of large earthen and shell mounds," Binghamton University anthropologist Carl Lipo said in a statement. "Mounds and shell rings contain valuable information about the way in which past people lived in North America. As habitation sites, they can show us the kinds of foods that were eaten, the way in which the community lived, and how the community interacted with neighbors and their local environments."
Unfortunately for archaeologists, these mounds often remain hidden under dense canopies of trees and brush or in areas like bayous and swamps. Even drones, which increasingly have been used to discover ancient settlements in places like the United Kingdom, can have difficulty discovering these traces of history. Instead, archaeologists have increasingly been using LiDAR (light detection and ranging) mapping to pull back a region's vegetative blanket. Because this surveying technology uses laser pulses (up to 600,000 pulses per second), it's capable of revealing extremely fine details of the Earth's hidden topography.
Two previously known shell rings (shown in the image above) were also picked up using the new analysis system created by the research team. (Photo: Carl Lipo/State University of New York at Binghamton)
While LiDAR has given researchers a new method of discovery, it's also created an enormously deep pool of data that's difficult to comb through. In an effort to ease this burden, researchers at the State University of New York at Binghamton used object-based image analysis (OBIA) to program computers to do the searching for them. Using publicly available LiDAR maps of coastal Beaufort County, South Carolina, the researchers fed the OBIA program shape characteristics present in previously discovered ancient mounds and watched as the results came flowing in.
In a paper published in the journal Southeastern Archaeology, the team explained how the approach resulted in the systematic discovery of more than 160 previously unknown mound features.
"Through the use of OBIA, archaeologists can now repeatedly generate data about the archaeological record and find historic and pre-contact sites over massive areas that would be cost-prohibitive using pedestrian survey," professor Lipo added. "We can now also peer beneath the dense canopy of trees to see things that are otherwise obscured. In areas like coast South Carolina, with large swaths of shallow bays, inlets and bayous that are covered in forest, OBIA offers us our first look at this hidden landscape."
With LiDAR already in use by archaeologists in canopy-restrictive regions like Honduras and Cambodia, it's welcome news to see the technology also put to use to uncover ancient secrets in North America. Even better, according to Lipo, satellite and LiDAR data is now widely available for much of the Eastern Seaboard. With climate change and sea level rise poised to irrevocably alter our coastlines, he says there's little time to waste in discovering these lost footprints of human civilization.
"It is urgent we document this pre-contact landscape as soon as possible, in order to learn as much as we can about the past before it is gone forever," he added.