Lidar Reveals Hundreds of Pre-Columbian Geoglyphs in the Southwestern Amazon

Archaeologists flying over the tri-border region of Bolivia, Brazil and Peru have identified nearly 400 previously unknown earthworks—circles, squares and other geometric designs—carved into the rainforest floor. The findings, reported in a study published this week in *Nature*, were captured using airborne laser-scanning (lidar) that penetrates dense canopy cover. The researchers describe the features as “geoglyphs,” many of which are linked by linear embankments that resemble roads.

New York Times

The geoglyphs date from roughly 600 B.C. to 850 A.D., a period that predates European contact by more than a millennium. Their existence adds to a growing body of evidence that the Amazon was not an untouched wilderness but supported complex societies capable of large-scale earthmoving. The study’s authors argue that these constructions demonstrate organized labor and planning far earlier than traditionally assumed for the region.

New York Times

Most of the newly documented figures cover about seven acres each, with surrounding ditches up to 30 feet wide and 15 feet deep. The largest single geoglyph spans more than 120 acres, illustrating a remarkable degree of landscape alteration. The sheer number of sites—approaching four hundred—suggests a widespread network of settlements or ceremonial centers across the southwestern Amazon basin.

New York Times

If the geoglyphs indeed reflect coordinated activity by pre-Columbian peoples, scholars may need to revise models of population density, agricultural practices and sociopolitical organization in the Amazon. The discovery also underscores the value of lidar technology for uncovering hidden archaeological features in heavily forested environments.

New York Times

“This is an important and ambitious study, based on exceptionally extensive lidar coverage for this region, which reveals the remarkable scale of pre-Columbian landscape modification in southwestern Amazonia,” — José Iriarte, an archaeologist at the University of Exeter

New York Times