Lidar study reveals much more dense early urban Amazon settlements


Rio Branco in the Amazon rainforest of Roraima state, Brazil. 

May 25 (UPI) -- Evidence of early urbanism has been found in the Amazon through the first-time use of Light Detection and Ranging technology. The lidar study found evidence of much more dense urban settlements than were previously thought to exist.

According to research from the University of Bonn, lidar revealed remarkably large sites where urban settlements once existed.

The new study mapped a total of 200 square kilometers of the Casarabe cultural area in the Mojos Plains, a southwestern fringe of the Amazon region.

The Casarabe cultural area dates to the period between 500 and 1400 AD.

Excavations done there more than 20 years ago found two mounds and many visible traces of settlements in the time before Spanish colonization in the 16th century.

Conventional archeological surveys uncovered a terraced core area, canals and a ditch-wall enclosing the site. But deeper structural details were not revealed until now with the lidar tool.

"So the entire region was densely settled, a pattern that overturns all previous ideas," says Carla James Betancourt, who is a member of the Transdisciplinary Research Area "Present Pasts" at the University of Bonn.

The study's conclusion said that this work has "put to rest arguments that western Amazonia was sparsely populated in pre-Hispanic times."

Instead the lidar findings show that the inhabitants of the Casarabe cultural area created a new social and public landscape through monumentality.

"The scale, monumentality, labor involved in the construction of the civic-ceremonial architecture and water-management infrastructure, and the spatial extent of settlement dispersal compare favorably to Andean cultures and are of a scale far beyond the sophisticated, interconnected settlements of southern Amazonia, which lack monumental civic-ceremonial architecture," the study said.

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The researchers on this study said the real archeological work in this region of the Amazon is just beginning. They said the goal now is to understand how these large regional centers functioned.