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When archaeologists in Georgia conducted test excavations in a 3,000-year-old fortress, they worked in tall summer grass. When they returned in the fall, however, they discovered that the flora had previously concealed something shocking.
Using drone technology, researchers in the UK, Georgia and the US have mapped the expansion of Dmanisis Gora, a Bronze Age “mega-fortress” in the Caucasus Mountains, and discovered that the complex is 40 times larger than previously suggested. His research, detailed in a January 8 study published in the magazine Antiquitycould provide insight into the patterns of growth and urbanization of ancient settlements around the world.
“Using drones allowed us to understand the importance of the site and document it in a way that simply wouldn’t have been possible on the ground,” said Nathaniel Erb-Satullo of the Cranfield Forensic Institute, who has participated in the study. in a Cranfield University statement. “Dmanisis Gora is not only a significant discovery for the South Caucasus region, but has wider significance for the diversity in the structure of large-scale settlements and their formation processes.”
The Caucasus is a geographical region comprising parts of Russia, Georgia, Azerbaijan and Armenia, and an ancient crossroads of many different cultures, including local populations. Large fortress settlements began to develop in the South Caucasus region between 1500 and 500 BC, according to the study.
Erb-Satullo and his co-director, Dimitri Jachvliani from the National Museum of Georgia and a participant in the study, began to investigate Dmanisis Gora in 2018. After initial test excavations, the team again discovered that the landscape of the fall had revealed additional fortification walls and stone structures far beyond the inner fortress they had previously detected. The complex was evidently much larger than they had thought, but they found it impossible to document how large from the ground.
“That’s what sparked the idea of using a drone to assess the site from the air,” Erb-Satullo said. The researchers used a drone to take nearly 11,000 photos of the site, which they then put together to create digital elevation models and orthophotos: aerial photographs corrected to account for elements such as the angle from which the photo was taken.
“These datasets allowed us to identify subtle topographical features and create accurate maps of all the fortification walls, tombs, field systems and other stone structures in the outer settlement,” added Erb-Satullo. “The results of this survey showed that the site was more than 40 times larger than originally thought, including a large outer settlement defended by a 1 km long fortification wall.” A kilometer is approximately 0.62 miles.
Erb-Satullo and his colleagues compared the orthophotos to Cold War-era spy satellite images declassified in 2013 to analyze how the site had evolved over the past five decades, highlighting the intrusion of modern agriculture.
Although modern expansion threatens the site, researchers hypothesize that thousands of years ago, Dmanisis Gora itself underwent impressive urban growth “due to its interactions with mobile pastoral groups,” explained Erb-Satullo. “Its large outdoor settlement can be expanded and contracted seasonally,” he added.
Now, the team hopes to use the newly collected data to further investigate elements such as population density and intensity, livestock movements and farming practices.
Ultimately, the drone map of Dmanisis Gora sheds light on the megafortress, as well as on broader patterns of Late Bronze Age and Iron Age societies as a whole. It is also another example of declassified spy satellite images lending a hand to archaeologists decades after the pictures were taken.
