Using remote laser scanners mounted on helicopters, archaeologists have been able to peer below the forest canopy of the Amazon, revealing the layouts and links of ancient villages laid out like clock faces.
While so-called hill villages have been observed before, new surveying technology revealed exactly how they were organized on a large scale, gathering data without the need for hard work and digging on the ground.
Results are made possible by LIDAR scanning technology, the same long-distance depth-sensing technology found in various forms in self-driving cars and even in the latest Apple iPhones.
“LIDAR has allowed us to detect these villages, and their features such as roads, which wasn’t possible before because most are not visible within the best satellite data available,” says archaeologist José Iriarte, from the University of Exeter in the UK.
Instead of working from hill to hill, as happened in the past, scientists were able to see the blueprints of entire villages and the connections between them, via the RIEGL VUX-1 UAV LIDAR sensor that monitors the forest from above.
The surveys showed how villages, built between 1300-1700 CE, were arranged to represent very specific social models, without a clear hierarchy.
“The uniform spatial layout of the mound villages, like many contemporaneous ring villages of the Neotropics, are likely to represent physical representations of the Native American cosmos,” the team writes in their paper.
Scientists discovered small and major high-banked long, sunken roads with high banks by LIDAR, which radiated from hill villages like sunshine or the clock. Most of the villages showed two roads leaving to the north and two roads to the south.
“LIDAR provides a new opportunity to identify and document dirt sites in forested parts of the Amazon that are characterized by dense vegetation. It can also document the smallest surface earth features in recently opened grassland areas,” says Ariart.
Between 3 and 32 mounds were found at each site, with the mounds themselves as high as 3 meters (9.8 feet) in some cases, and stretching up to 20 meters (65.6 feet) in length. Closer investigation in the future should be able to reveal exactly what these mounds were used for – from houses to cemeteries.
In total the archaeologists studied some 36 villages, with some as little as 2.5 kilometers (1.6 miles) apart. As well as circular and elliptical villages, researchers also found them arranged in more of a rectangular shape.
“The technology helps to show the diverse and complex construction history of this part of the Amazon,” says Iriarte.