- Archaeological studies in the Tapajós region of Brazil’s Pará state have unearthed rich historical knowledge about the human occupation of the Amazon, recording some of the most ancient relics found in the Americas.
- But the region has become the target of industrialized illegal mining, which is leaving massive destruction in its wake and threatening to erase tens of thousands of years of historical discoveries.
- Hydroelectric plants, ports, waterways, railways and dams are also planned in the region, which would also directly impact Indigenous and local communities.
- At the same time, the Brazilian government under President Jair Bolsonaro has slashed funding for research and issued executive orders allowing caves to be demolished and prospecting to be made easier.
The myth of a “demographic void” in the Amazon and of the “virgin forest” has been systematically debunked by a series of scientific studies showing that the rainforest has a history of human occupation stretching back millennia.
Archaeology plays a central role in revealing the historical, cultural and socioeconomic richness of this past. Recent discoveries have reinforced findings from the 1970s and 1980s in the Tapajós region in the Brazilian state of Pará.
The report “Tapajós Sob o Sol” (“Tapajós Under the Sun”), released by the NGO International Rivers, brings together many of these unprecedented archaeological findings — while underscoring that the research is under threat from the massive industrialization of illegal mining. The destructive forces of mining combined with the advance of the farming frontier and a series of infrastructure projects planned for the Tapajós region — hydroelectric plants, ports, waterways, dams and railways — risk erasing this ancient history.
Brazil’s National Historical and Artistic Heritage Institute (IPHAN) lists 375 archaeological sites in the municipalities that make up the Tapajós River region: 134 in Itaituba, 81 in Santarém, 65 in Jacareacanga, 59 in Belterra, 21 in Rurópolis, nine in Novo Progresso, and six in Aveiro.
“The idea of the great void, the myth that the forest is pristine, paves the way for the viewpoint that natural resources are there to be exploited,” says report co-author Bruna Rocha, coordinator and adjunct professor of archaeology at the Federal University of Western Pará (UFOPA). “When we look at the information that archaeology provides, the idea that we are dealing with empty areas is debunked. We can no longer look at these areas as if there they are unoccupied, because they have owners.”
Most of these archaeological sites point to sustained human occupation, meaning these communities were more sedentary in nature than the nomadic stereotypes often associated with the Amazon. Their presence in the region dates back at least 2,000 years.
Objects like chipped stone arrowheads, found in different locations along the Tapajós, suggest that the first humans to inhabit the region were there from even earlier, possibly even in the transition between the Pleistocene and Holocene epochs, about 10,000 years ago.
There are also indications that, beginning about 4,500 years ago, these communities were practicing forest polyculture, growing corn, sweet potato, grains and tubers. Established agroforestry led to demographic growth in the villages of the Lower Tapajós region, including in the Arapiuns River region during the first millennium A.D.
This increased concentration of people is proven by the large number of sites where so-called Amazonian dark earth, or ADE, has been found. These man-made soils were created by accumulating organic residue and charcoal from controlled burning, to enrich the otherwise poor Amazonian soils. They indicate the deep social changes that took place in the Amazon some 4,000 years ago.
“Dark earth is an indication that there were many more people living along these rivers in the past than there are today. Aside from urban areas, anywhere you look along the riverbanks, archaeological sites can be found,” says Rocha, who has studied the region since 2010 and has been involved in the studies behind several of the findings.
Important markers for sites of human concentration, ADE soil layers can be as deep as 4 meters (13 feet). “Dark earths are important for agriculture of many types of crops in the region,” Rocha says. “Native peoples would choose regions with dark earths to establish new villages because they guaranteed favorable botanical and vegetal infrastructure for life like fruit trees and medicinal plants.”
A study published in December 2021, based on DNA analysis of Indigenous people from Brazil and other countries in South America, presented new evidence that the Amazon was inhabited by millions of people before the first Europeans arrived.
Rocha notes that in areas like the Caverna da Pedra Pintada (Painted Rock Cave), in Pará’s Monte Alegre State Park, some of the earliest human sites in the Americas have been recorded. Near the western Pará city of Santarém, the Taperinha archaeological site holds the oldest ceramics ever found on the continent.
600 kilometers of contaminated rivers
But these historical and cultural treasures are under serious threat from the spread of illegal mining activities.
On the Munduruku and Sai Cinza Indigenous reserves, in the mid-Tapajós region of southwestern Pará, illegal mining has devastated at least 632 kilometers (393 miles) of rivers since 2016. This figure marks a more than 2,000% increase over a five-year period.
The waterways most affected by the illegal mining are the various tributaries of the Tapajós. Studies carried out by the Oswaldo Cruz Foundation, Brazil’s leading public health research institute, have found that 100% of the Indigenous Munduruku people living in the region have high mercury levels in their bodies.
“Mining has destroyed countless archaeological sites and done irreversible damage to the landscape,” Rocha says. “They tear apart all the layers of cultural soils that hold archaeological artifacts. It is a very, very violent process.”
But with mining activity racing ahead, and archaeological research hobbled by lack of funds, it’s now the illegal miners who are often first to uncover archaeological artifacts. “They dig and find artifacts, even wooden ones at times, which are very hard to come by. But it’s all lost,” Rocha says, adding there needs to be an evaluation of the cumulative impact of all the projects underway on the Tapajós.
These activities rarely defer to the Indigenous inhabitants’ rights to consultation or veto power, enshrined in Brazil’s ratification of the International Labour Organization’s Convention 169.
“The Tapajós River is a sacred river to us,” says Juarez Saw Munduruku, a chief whose village in the Sawré Muybu Indigenous Territory sits on an archaeological site rich in dark earth. “It was created by Karosakaybu [a sacred Munduruku ancestor]. Some Munduruku became fish, others became birds, other trees, others pigs. We know how the river was made, and it has a relationship to our history and the history of the forest.”
Caves left vulnerable and funding slashed
In January, President Jair Bolsonaro published Decree 10.935, authorizing the destruction of caves to make way for new projects. The executive order also applies to caves that hold the most ecological, historical and cultural importance.
Driven through by the mining sector, this order, which has since been suspended by the Federal Supreme Court (STF), places Brazil’s archaeological heritage at risk.
“Caves are privileged places from an archaeological standpoint because the deterioration of historical artifacts happens at a much slower rate in these environments,” Rocha says. “We have the chance of finding much older traces than we can at sites in the open air.”
Bolsonaro has relied heavily on pushing through his agenda by way of executive orders, bypassing the scrutiny of Congress. The order on caves was followed by two other decrees simplifying approval processes by the National Mining Agency and making it easier to prospect for minerals.
At the same time, the Bolsonaro administration has drastically cut funding for research in Brazil. For this year, the federal government has slashed 600 million reais ($121 million) in research funding, or 92% of all funding for the Ministry of Science, Technology and Innovation. In all, the ministry has lost 60% of its funding compared to 2015.
This makes it much more difficult for research to be carried out in all fields of science, and archaeology is no exception. “We have always worked with few resources and we are talking about a large stretch of territory,” Rocha says. “These aren’t easily accessible places. Travel and logistics are expensive and this situation compromises the construction of knowledge.”
Bush, M. B., Nascimento, M. N., Åkesson, C. M., Cárdenes-Sandí, G. M., Maezumi, S. Y., Behling, H., … McMichael, C. N. H. (2021). Widespread reforestation before European influence on Amazonia. Science, 372(6541). doi:10.1126/science.abf3870
Castro e Silva, M. A., Ferraz, T., Couto-Silva, C. M., Lemes, R. B., Nunes, K., Comas, D., & Hünemeier, T. (2021). Population histories and Genomic diversity of south American natives. Molecular Biology and Evolution, 39(1). doi:10.1093/molbev/msab339
Banner image of a ceramic vase found in the Tapajós region dating back around 1,000 years. Image courtesy of the National Museum of Brazil (CC BY-SA 4.0).