Using remote laser scanners mounted on helicopters, archaeologists were able to peer under the canopy of the Amazon forest, revealing the layout and connections of ancient villages arranged like clock faces.
These Amazonian villages known as “mounds” (mounds of earth and stones) had been previously identified, but it is today that we understand them all. The new sensing technology has revealed exciting new data: first of all their exact location, a real hidden network, and then the scale on which they were organized.
Most notably, the data was collected without the need for laborious groundwork and excavation.
Blessed be the LIDAR
The results were made possible thanks to LIDAR scanning technology, the same long-distance depth sensing technique found in various forms in self-driving cars and even the latest smartphones.
Il TO DEAL allowed us to detect these villages and their features such as roads, which was previously not possible because most were not visible in the best available satellite data
José Iriarte, archaeologist from the University of Exeter, UK
Hidden network of Amazonian villages: representations of the cosmos
Instead of working from one mound to another, as has been the case in the past, the researchers were able to see the layouts of entire villages and the connections between them, via a UAV LIDAR RIEGL VUX-1 sensor that monitors the forest from high.
The scans showed how villages - built between 1300-1700 AD - were organized to represent very specific social patterns, without a clear hierarchy.
"The uniform spatial arrangement of mountainous villages, like many contemporary Neotropic ring villages, is likely to physically represent the Native American cosmos," the team writes in the paper.
What was there in place of the mounds?
Between 3 and 32 mounds have been found at each site, with the mounds themselves up to 3 meters (9,8 ft) high in some cases and extending up to 20 meters (65,6 ft) in length. A deeper investigation in the future should be able to reveal exactly what these mounds were used for, from homes to cemeteries.
LIDAR has discovered, as part of this hidden network, also long secondary and main roads with high banks, that radiate from the mountainous villages like sunbeams or the hands of a clock. Most of the Amazonian villages had two roads leading north and two south.
“LIDAR offers a new opportunity. That of identifying and documenting the dirt sites in wooded areas of the Amazon characterized by dense vegetation ”, says Iriarte. "It can also document the smallest surface land features in recently opened grazing areas."
An important discovery
In total, the archaeologists studied a hidden network of approx 36 villages Amazonians, some just 2,5 kilometers (1,6 miles) apart. In addition to the circular and elliptical villages, the researchers also found them arranged in a more rectangular shape.
Research fills some gaps. First of all in terms of the history of this part of the Amazon rainforest. The southeastern sector of Brazil's Acre state, which was thought to have been sparsely inhabited over the centuries, also now has a new perspective.
However, the work is only preliminary: there is much more to discover about these orderly ancient settlements. It will take a closer look at these newly discovered clock face mounds and the artifacts that can be found in them.