Beneath the barren New Mexican desert, there are remnants of an ancient Pueblo society that thrived some 1,000 years ago. John Kantner, an archaeologist from the University of North Florida, has surveyed the red sands for 20 years in search of ancient religious structures called kivas. Similar to small family chapels, kivas were circular rooms where members of the Chaco group went to perform ceremonies and rituals. Located under the household, the small spaces were buried and filled with soil as centuries passed.
Kantner had uncovered some kivas during his two decades in the desert, but searching for the subterranean structures on foot was difficult and time consuming. He, like many other archaeologists, decided to use technology that is revolutionizing his field: drones.
A buried archaeological feature retains heat differently than the surrounding soil. So Katner used drone surveillance along with thermal imaging to key in on subtle temperature differences while the structure heats and cools. He teamed up with Jesse Casana, an archaeologist from the University of Arkansas who had previously equipped aerial machines with thermal imaging technology for archeological research in Cyprus and Iraq. (Although thermal imaging has been around for decades, pairing it with drone technology is new.)
The team flew its eight-rotor drone multiple times before dawn when the desert was at its coolest. It took snapshots of the heat patterns every second. Each frame extracted from the thermal camera provided just a footprint of the ground, but combined together, it created a mosaic of what was beneath the entire area. The team was able to detect heat signals beneath the sand which revealed several kivas. “In the end it was two hours of work to find something that I’ve spent years trying to find,” said Kantner. “That’s pretty remarkable.” They published their findings last year in the Journal of Archaeological Sciences.
Drones may also offer new research opportunities when coupled with laser imaging systems like LiDAR, which creates high-resolution maps and can reveal hidden structures that are otherwise impossible to detect. “What we’ll see in the next year or so that will blow the doors off in archaeology will be drone based LiDAR,” Casana said. But LiDAR equipment is expensive, and Casana notes that some researchers might be reluctant to mount the device onto drones, which crash often. “If you can get people to get a drone to carry LiDAR reliably that would be great for archaeology,” he said. “People are salivating to get this to work.”