Amazon LiDAR survey reveals extensive ancient Aquiry earthworks

A LiDAR (light detection and ranging) survey of southwestern Amazonia has revealed extensive evidence of an ancient, large-scale civilization known as the Aquiry. By using aircraft-mounted lasers to penetrate the forest canopy, researchers identified 432 earthworks within a 4,497 square kilometer area in Brazil, 396 of which were previously unknown.

Based on the density and distribution of these findings, researchers estimate that more than 20,000 earthworks may exist across the wider Aquiry cultural landscape. The structures include geometric enclosures, such as circles, squares, and octagons, as well as ditches, raised embankments, platforms, and roads.

The study, published in Nature, suggests the Aquiry civilization flourished between roughly 600 BCE and AD 850, with a population peak occurring between AD 100 and 300. During this period, the researchers estimate the broader cultural area may have supported between 1.25 million and 3 million people. The scale of these constructions indicates a much higher precolonial population density than previously understood for the Amazon region.