Lidar Reveals 432 Ancient Earthworks in Amazon, Uncovering Aquiry Civilization
A pioneering lidar survey in the Brazilian Amazon has documented hundreds of previously unknown geoglyphs, reshaping estimates of pre-Columbian population density.
Talivio News · Global2 min read
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Hidden beneath the dense canopy of the Amazon rainforest, ancient geometric earthworks have been brought to light by lidar technology, revealing the scale of a pre-Columbian civilization in Southwest Amazonia. The structures, known as geoglyphs, were built by the Aquiry civilization and include ditched enclosures that served as ceremonial and political centers.
In 2024, lidar surveys covered 4,497 km² across the states of Acre and Amazonas in Brazil. The surveys documented 432 earthworks, of which only 36 were previously known, according to the research.
432 earthworks
Documented by lidar; only 36 were known before.
The Aquiry civilization, named after the region, built geoglyphs over a vast area of approximately 183,000 km². The geoglyphs range in size from 0.35 to 14 hectares, with the largest nearly 50 hectares. Their ditches are 9–13 meters wide and up to 5 meters deep.
Researchers estimate that the total number of earthworks across the entire region may exceed 20,000, with a specific range of 24,000–30,000. About two-thirds of these are attributed to the Aquiry civilization. The known earthworks in the study area grew from 60 to 200 to 1,279 over successive surveys.
The Aquiry civilization peaked between 100–300 AD, with about 60% of structures in use simultaneously. During that period, the population of the Aquiry region is estimated at 1.25 to 3 million people. This figure is part of a broader reassessment: pre-Columbian population estimates for Greater Amazonia (about 6.7 million km²) have been revised upward to 5–10 million, from earlier estimates of 1.5–2 million.
The studied area represents less than 3% of the entire Amazon rainforest. The interfluvial hinterland (terra firme), which covers more than 90% of Amazonia, appears to have supported relatively dense human populations, challenging traditional views of the region as sparsely inhabited.
Most earthworks detected—92%—were within 210 kilometers of Rio Branco, while 8% were near Lábrea. Lidar penetration was about 10% lower in the Lábrea area due to denser forest, and a significant portion of the surveyed ground lacked sufficient point clouds for visualization.
The Aquiry civilization practiced intensive agroforestry, promoting beneficial tree species such as Brazil nut and edible palms. They intentionally burned bamboo-rich land to maintain soil fertility, a practice that may explain ancient charcoal layers previously attributed to natural fires. Researchers suggest these findings call for a reassessment of South America's pre-Columbian population density and its impact on soil and biodiversity.
Construction of an average geoglyph would have required about one year of work by a group of 300 people, assuming each adult moved one cubic meter of soil per day.
Updates
Bayesian modelling dates the construction of the Aquiry geoglyphs between 600 BC and AD 850, identifying them as ceremonial and political centres rather than defensive settlements. The surveyed structures extend across regions of Brazil, Bolivia, and Peru, with 347 distinct earthworks identified within the study area. These findings contrast with the fortified enclosures observed in other Amazonian locations such as Llanos de Mojos, which date to between the 13th and 17th centuries AD.
Bayesian modeling now dates these geoglyphs to between 600 BC and AD 850, identifying them as ceremonial and political centers rather than defensive sites or permanent settlements. Structural analysis reveals 347 distinct earthworks characterized by embankments situated outside or on both sides of ditches, with the civilization's geographic boundaries spanning regions across Brazil, Bolivia, and Peru. These features are distinguished from later 13th to 17th-century fortified circular ditches found in the Bolivian lowlands and the upper Xingu and Tapajós basins.
Bayesian modelling indicates the Aquiry civilization's geoglyphs were constructed between 600 BC and AD 850, with the society experiencing a rapid decline and abandonment between 850 and 950 AD. Led by Martti Pärssinen from the University of Helsinki, the research team estimates that the regional population during the Aquiry peak, which occurred between 100 and 300 AD, was between 1.25 and 3 million people. Additionally, unverified reports suggest that the total number of recorded earthworks in the region has now reached 1,700 following the latest discoveries.
Bayesian modeling indicates that the Aquiry civilization's geoglyphs were constructed between 600 BC and AD 850, with the society experiencing a rapid decline and settlement abandonment between 850 and 950 AD. Led by Martti Pärssinen from the University of Helsinki, the research team identified that the civilization's peak occurred between 100 and 300 AD, supporting an estimated regional population of 1.25 to 3 million people. Additionally, unverified reports suggest the total number of recorded earthworks in the region has reached 1,700 following the latest discoveries.
Bayesian modelling indicates the Aquiry civilization's geoglyphs were constructed between 600 BC and AD 850, with the culture experiencing a rapid decline and abandonment of settlements between 850 and 950 AD. Led by Martti Pärssinen from the University of Helsinki, the research team estimated the regional population at its peak was between 1.25 and 3 million people. Additionally, unverified claims suggest the total number of recorded earthworks in the region has reached 1,700 following the latest discoveries.
Bayesian modeling indicates the Aquiry civilization's geoglyphs were constructed between 600 BC and AD 850, with a peak period occurring between 100 and 300 AD. During this zenith, the regional population is estimated to have been between 1.25 and 3 million people, with nearly 60 percent of discovered structures in use. Lead researcher Martti Pärssinen from the University of Helsinki confirmed the Aquiry people lived in multi-family longhouses near ceremonial centers, cultivating maize and squash.
Bayesian modeling indicates the Aquiry civilization's geoglyphs were constructed between 600 BC and AD 850, with the society experiencing a rapid decline and abandonment of settlements between 850 and 950 AD. Led by Martti Pärssinen from the University of Helsinki, the research suggests that during the Aquiry peak period between 100 and 300 AD, the regional population reached between 1.25 and 3 million people. Furthermore, unverified reports claim the total number of recorded earthworks in the region has reached 1,700 following these latest discoveries.
