Geologists discovered plastiglomerates — beach materials welded together by melted plastic — in March on Trindade Island, a remote volcanic outcrop more than 700 miles off Brazil's coast. Much of the plastic likely comes from lost fishing nets and has been found in areas protected for green turtle nesting. Experts warn these plastic-rock hybrids could persist in the geological record for millions of years and view the find as evidence of human-driven change in Earth's geology. They urge policy action and individual steps to reduce plastic waste.
Scientists Find 'Plastiglomerates' — Plastic-Welded Rocks — on Remote Brazilian Island
Geologists have discovered rocks fused with melted plastic on Trindade Island, a remote Brazilian volcanic outcrop more than 700 miles from the mainland that serves as a vital nesting refuge for green turtles. The discovery, made in March, shows how human plastic pollution is being incorporated into geological materials.
What Researchers Found
The research team identified fragments of volcanic beach material in which once-molten plastic has mixed and solidified with sand, shells, rock fragments and other organic debris. Scientists call this hybrid material a "plastiglomerate" — a new type of geological marker of human influence on the planet.
"The pollution, the garbage in the sea, and plastic dumped incorrectly in the oceans is becoming geological material ... preserved in the earth's geological records," said Fernanda Avelar Santos, a geologist at the Federal University of Paraná.
Sources And Local Impact
Researchers report that much of the plastic appears to come from lost or discarded fishing nets and gear, which are common on Trindade's beaches. These plastics can melt under high temperatures and fuse with natural beach materials, creating lasting, rock-like formations.
The plastic-bearing rocks were found within areas of Trindade that are permanently protected so green turtles can lay their eggs. The only human presence on the island is personnel from the Brazilian Navy, who are stationed there to safeguard the nesting sites.
Broader Significance
Scientists say plastiglomerates may persist in rock layers for millions of years, making them potential future fossils and a signal of a new, human-dominated geological epoch often called the Anthropocene. "Plastics and plastiglomerates might well survive as future fossils," said Jan Zalasiewicz, a geologist at the University of Leicester.
Abandoned fishing gear poses a serious threat to marine ecosystems: researchers estimate that about 100 million pounds of plastic enter the ocean each year as a direct result of lost fishing equipment.
What Can Be Done
Addressing the issue requires both policy and individual changes. Governments can prioritize greener policies and better waste management, while consumers can reduce single-use plastics and choose durable, reusable alternatives. Practical swaps include reusable water bottles, solid shampoo bars and dissolvable dishwasher or laundry pods. Proper recycling and responsible disposal of fishing gear are also crucial.
As Patricia Corcoran, a geologist at the University of Western Ontario, observed: "Even small things make a difference."
