Highway work in Brazil's Amazon leads to digs and new findings

Archaeologists say road paving in the Amazon rainforest can accelerate deforestation that threatens communities that live there, but it can also create access that helps researchers document the region’s past. In Brazil’s northern state of Amapa, surveys carried out before paving along the BR-156 highway have led to multiple discoveries dating to periods long before Europeans arrived, according to reporting by the Associated Press.

So far, scientists working around nine dig sites connected to the highway project have found pottery vases that may have served as funerary urns, as well as small artifacts that resemble human faces. Lúcio Flávio Costa Leite, who manages the Archaeological Research Center at Amapa’s Institute for Scientific and Technological Research, described what researchers see as a tradeoff created by infrastructure projects. “What we now about the region’s past is also tied to the opening created by these projects, which gives our relationship with them a somewhat ambivalent character,” he said, adding that the knowledge gained from the sites leads researchers to pay closer attention and adopt permanent protection measures.

The AP report said the items recovered from BR-156 have been cleaned and analyzed by a team working for the National Department of Transport Infrastructure. It quoted archaeologist Manoel Fabiano da Silva Santos describing the soil layers as a “historic timeline” and said the team found European-era items in upper layers, including Portuguese porcelain and nails linked to European occupation.

Santos said that digging deeper uncovered pottery and ceramics associated with earlier Indigenous presence, reflecting a shift in the site before and after colonizers arrived. The artifacts from the BR-156 work are expected to be placed in the state collection overseen by Costa Leite, which he said holds about 530,000 pieces. He also said the oldest item recovered so far is around 6,140 years old, which he described as evidence of a long human presence across Amapa.

The report also connected those findings to broader research efforts aimed at challenging older ideas that the region was largely empty of complex human activity before European contact. Scientists described the Amazon past as a landscape shaped by interconnected Indigenous societies, with the material found along BR-156 including pottery in multiple styles and techniques that reflected influences ranging from Brazil’s Para state to the Caribbean.

In addition to the highway-related digs, the AP report highlighted archaeological work in Calcoene, a city in Amapa known for the Archaeological Park of the Solstice. Researchers have described the area as a 1,000-year-old stone monument made up of 127 carved monoliths arranged in a circle about 30 meters (98 feet) in diameter, located in open grassland amid the rainforest and bordered by a slow river. Some researchers have compared it to Britain’s Stonehenge because of the stone arrangement.

Mariana Petry Cabral, a professor at the Federal University of Minas Gerais who participated in the team that began excavating at the site about two decades ago, said researchers found the stones were positioned so that during the Northern Hemisphere’s winter solstice, they marked the exact point where the sun rises. She also said the meaning of every stone is not fully known, but that “they are not from the site itself” and were brought from other nearby locations. The report said subsequent research and excavations identified the site as a burial ground, with radiocarbon dating indicating it was occupied for hundreds of years beginning around 1,100 years ago.

The AP report said the site was discovered in 2005 and can be visited with prior approval from Amapa’s Institute for Scientific and Technological Research. It also said the site is undergoing a process to become a national park, a change intended to allow more visitors. It noted that Brazilian law protects such archaeological sites by prohibiting alterations, which it said also adds a layer of protection for surrounding rainforest.

Beyond individual sites, the AP report said scientists studying modern archaeological and historical ecology have used satellite-based methods to identify networks of roads and patterns hidden beneath the forest canopy. Eduardo Neves, an archaeologist at the University of São Paulo who has studied the Amazon for more than 30 years and since 2023 has led the Amazon Revealed project, said scans have revealed roads linking archaeological sites and buried patterns in the rainforest that point to repeated occupation and deliberate landscape modification. He said the scans show networks of roads connecting clusters of settlements across the forest, especially in southern Amazonas state and Acre.

Neves said archaeologists had long suspected these connections but that technology makes it possible to see their broader geographic reach. He also said the evidence indicates interconnectivity between different settlements rather than isolated communities, quoting him as saying, “When people think of an Indigenous tribe, they often imagine a small village isolated in the middle of the forest. But evidence shows a high degree of interconnectivity linking different settlements.” Cabral added that Amapa is key to understanding how Indigenous populations maintained networks of exchange for millennia, according to the AP report.