Amazonian Geoglyphs, Evidence of an Unknown Civilization
The European colonization of Rondônia and Acre is relatively recent. The first Portuguese explorer to reach the area was Antônio Raposo Tavares in 1650. However, it wasn’t until 1770 that some Portuguese settlers established themselves in the region with the construction of Forte Príncipe da Beira on the banks of the Guaporé River in 1776.
Despite this, the current state of Rondônia remained inhabited only by isolated indigenous groups until the late 19th century, when explorer Cândido Rondon completed several expeditions in the area.
The state of Acre, which originally belonged to Bolivia, was acquired by Brazil only in 1903, and it was from that point that gradual colonization began.
From an anthropological perspective, it is known that the tribes inhabiting the territories of these two states were numerous and formed complex societies, although little is known about them.
Studies by some linguists indicate that while tribes belonging to the Pano linguistic group lived along the Juruá River (in Acre), indigenous groups speaking Arawak languages resided in the Purus River and Acre River basins (in Acre).
Since the vast majority of indigenous groups living in the Madre de Dios, Beni, Mamoré, and Guaporé river basins (mainly the Moxos) also belonged to the Arawak linguistic family, it is possible to hypothesize a certain cultural continuity across a region extending from the Purus River to the Mamoré River, including parts of Rondônia adjacent to the Guaporé River (the area of the historical Paititi).
The basin of the Rio Machado (a direct tributary of the Rio Madeira) was inhabited by indigenous groups speaking Tupi-Guarani languages.
In the Arawak-influenced area, now part of Brazil (Acre), several geoglyphs—large geometric patterns on the ground visible only from the air—have been discovered since 1977.
The first geoglyph, circular and approximately 100 meters in diameter, was spotted in 1977. The second discovery, also in Acre, occurred in 1985 and consisted of a large quadrangular geoglyph enclosed within a circular one.
These geoglyphs, which result either from excavations (ditches) or constructions (earthworks), are also visible in Bolivia's Pando and Beni departments and in Brazil's state of Rondônia.
In Acre, the most significant geoglyphs are located on the Jaco Sá property (09º 57'39.9'' S, 67º 29'43'' W) and the Colorada property (9º 52'15'' S, 67º 31'55'' W). These sites feature quadrangular geoglyphs (with sides measuring about 150 meters) and circular ones (with diameters of approximately 150 meters).
Other geoglyphs in Acre include those on the Calazon da Silva property (10º 01'18'' S, 67º 30'23'' W) and the Baixa Verde property (10º 02'57'' S, 67º 32'07'' W), both quadrangular. Pottery discovered near these geoglyphs has been carbon-dated to 1294 CE.
In Rondônia, several geoglyphs have also been identified. During my recent trip to Brazil, I studied one of these geoglyphs in the Nova Brasilândia area with researcher Joaquim Cunha da Silva.
This geoglyph is circular, about 200 meters in diameter, located in a cornfield, with part of it concealed by the forest.
Other circular geoglyphs in Rondônia are visible from the air in deforested areas. It is likely that many more geoglyphs remain undiscovered, hidden in the forests of both Acre and Rondônia.
The most widely accepted hypothesis about the origin of these geoglyphs is that they were ancient canals or earthworks that marked the boundaries of fortified villages. Chronicles from the conquistadors (such as Schnidel's account from 1554) describe villages protected by high wooden palisades.
If these were fortified villages, it suggests that the inhabitants needed to defend themselves against invaders. The expansion of Tupi-Guarani and Pano-speaking peoples into territories previously inhabited by Arawak-speaking groups might partially explain this theory.
However, this hypothesis does not account for the double geoglyphs, such as those composed of a circle within a square, like the one on the Jaco Sá property. Could some of these geoglyphs have been created for ritual purposes, perhaps as a tribute to deities, similar to the Nazca geoglyphs?
YURI LEVERATTO
