The ruins of a city of a huge ancient civilization, hidden under the densely forested landscape of the Bolivian Amazon for centuries, were mapped with unprecedented details of laser technology, reports The Time.
The vast settlement stretches for about 80 square miles in Bolivia and includes pyramids, bridges, canals, fortress walls, and buildings arranged in ways that hint at a cosmological worldview.
The structures were built by a local population known as the “kasarabe” which flourished from 500 to 1400 AD. and inhabits about 1,700 square miles of the Amazon rainforest. The finding is staggering, according to one member of the research team.
Until a few months ago, only field research and indigenous legends led researchers to find in the dense Amazon jungle. Today, the credit goes to sophisticated remote-sensing technology that works with laser light (LIDAR).
Scientists led by Heiko Prumers, an archaeologist at the German Archaeological Institute in Berlin, are using LIDAR to study the remains of two large settlements called Kotoka and Landivar, along with 24 smaller sites, including 15 previously unknown to modern humans. researchers.
“The results show that the ‘casarabe’ settlement pattern is a type of low-density tropical urbanism not previously described in the Amazon.” This finding rejects the thesis that the Western Amazon was sparsely populated in pre-Hispanic times, according to a study published in the scientific journal Nature.
“We suggest that the casarabe culture system is the only form of low-density tropical agrarian urbanism – as far as we know, the first known case in the entire tropical lowlands of South America,” says Primers.
How do LIDAR laser scanners work?
LIDAR scanners fire laser pulses at ground targets from aircraft and record the time it takes for the signal to return.
In this way, the method can generate small details of the topography that are beyond the scope of other tools. LIDAR is a particularly popular tool for archaeologists working in densely populated areas, as they can uncover details of lost settlements that are difficult to spot or even inaccessible on land.
The abbreviation LIDAR was first used in 1953 in the work of Middleton and Spielhouse “Meteorological Instruments”. As a source of electromagnetic waves, the first lidars used ordinary or pulsed lamps, whose rays are transmitted through modulators to obtain a light pulse.
Lidars work with electromagnetic waves in the ultraviolet, visible, and infrared parts of the spectrum. Therefore, unlike radars, they can detect extremely small particles – water droplets, aerosols, and molecules, ranging in size from 10 to 250 nanometers.
In 1969, the distance to the moon was determined with the help of a laser rangefinder and a reflector delivered to the lunar surface by the Apollo 11 spacecraft. To this day, four reflectors placed over the years by Moonwalker-2 and various Apollo missions are used to monitor its orbit.
While some of the buried structures in the Llanos de Mojos area of the Amazon were already known to researchers, new LIDAR data revealed a wide network of road-related settlements that stretch for several miles through green terrain and where water is controlled by a huge system of channels and tanks.
Numerous signs of civic and ceremonial life are embedded in more densely populated areas, such as 70-foot cone-shaped pyramids and earthen buildings that curiously take the shape of the letter U.
While most of these monuments appear in more densely populated ruins, the scanned region may also contain countless small villages that are too small to be discovered by LIDAR, the team said.
The discoveries offer a fascinating view of a society that has flourished in this forested region for centuries, building massive agricultural infrastructure that sustains a rich social and ritual life.
