Mysterious Geoglyphs of Amazonia May Show Ancient Humanity Had an Major Impact on Rainforest
Evidence of ancient Amazonian civilization deep under the canopy of the rainforest is hoping to be revealed under a new initiative by international scientific agencies. Questions will be raised on how the ancient populations impacted the rainforest thousands of years ago.
A project grant of 1.7m-euro (£1.25m; $1.9m) from the European Research Council is backing the endeavor of a UK-led, international research team. They will be employing drones and laser instruments to detect hidden geoglyphs and evidence of ancient communities below canopy-level.
The unusual earthworks, which include square, straight, and ring-like ditches, were first uncovered in 1999, after large areas of forest were cleared for cattle grazing. Since then, hundreds of the earthen foundations have been found in a region more than 150 miles across, covering northern Bolivia and Brazil’s Amazonas state.
BBC News reports the aim of the project is to discover the “scale and activities of populations living in the late pre-Columbian period (the last 3,000 years before the Europeans arrived in the 1490s).”
The international team will be investigating the nature of the geometric earthen shapes, and looking to establish whether the sites demonstrate an ancient collective behavior.
Dr. Jose Iriarte of Exeter University, UK tells BBC News, "While some researchers think that Amazonia was inhabited by small bands of hunter-gatherers and shifting cultivators who had a minimal impact on the environment, and that the forest we see today is pristine and untouched for thousands of years - mounting evidence is showing this may not be the case.”
"This evidence suggests that Amazonia may have been inhabited by large, numerous, complex and hierarchical societies that had a major impact on the environment; what we call the 'cultural parkland hypothesis'," he continues.
Until recently this type of search for vegetation-shrouded earthworks would have proven near impossible for researchers. Drones and LiDAR (Light Detection and Ranging) technology make these investigations possible today. LiDAR was developed in the 1960s to analyze oceans and ice in the Arctic, but has been employed since in topography, geology and mapping.
Traditional aerial imagery, where only treetops are visible. Credit: PPS/EMBRAPA/US FOREST SERVICE
LiDAR imagery of the canopy. Credit: PPS/EMBRAPA/US FOREST SERVICE
The canopy is digitally removed to reveal the ground-level where the laser contacted, revealing any topographical details. Credit: PPS/EMBRAPA/US FOREST SERVICE
Archaeologists want to shed light on the dating and purpose of the geoglyphs, dwellings and ditches, which largely remain a mystery. More than 450 earthworks have been located in cleared areas of the rainforest. Some of the located works are clustered on a high plateaus, suggesting they may have been used for defense, however, others have theorized they were used for drainage or for channeling water, as they’re often near spring water sources. Others point to the geometric layouts, suggesting a ceremonial or religious function.
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Aerial photograph of ditches at Fazenda Parana. Credit: Edison Caetano, Antiquity Journal
Aerial photograph and plan of earthworks at Fazenda Colorada, which is made up of clear geometric shapes. Excavations suggest inhabitants lived in the three-sided square. Credit: Sanna Saunaluoma, Antiquity Journal
If the team is able to find evidence of ancient, large-scale occupation, this will lend weight to the idea that the rainforest we know today may be a result of the presence of early humanity.
Dr. Iriarte explains, "We want to see what is the human footprint in the forest and then inform policy, because it may be the case that the very biodiversity that we want to preserve is the result of the past historical manipulation of this forest.”
The initiative was announced at the annual meeting of the American Association for the Advancement of Science in California. The project findings may be used to shape future policy on sustainable forest use and the preservation of historical sites.
Featured Image: Ancient earthworks have been revealed due to land clearing. New techniques involving laser equipment may reveal evidence of occupation by ancient civilizations. Credit: Projecto Geoglifos – CNPQ
By Liz Leafloor