Plastic Rocks Found on a Remote Island in Brazil, Revealing How Humans Could Influence Geological Processes

The volcanic outcrop Trindade Island is just one of the few remote places on Earth. It would take about three to four days by boat from the coast of Brazil to reach the place.

So, geologist Fernanda Avelar Santos from the Federal University of Parana was shocked when she found an alarming indicator of human activities on the otherwise pristine landscape of the island. She saw "plastic rocks" or pebbles created from the abundance of plastic waste floating in the water.

Discovery of Plastic Rocks on Turtle Island

According to Phys.org, Santos discovered the plastic rocks in 2019 while visiting the island for research on a completely unrelated topic about landslides, erosion, and other "geological risks."

She was working near Turtle Beach, the world's greatest breeding site for the endangered green turtle, when she stumbled upon a massive outcrop of strange-looking blue-green rocks. She took some samples and returned them to her lab for further studies.

She and her colleagues recognized the specimens as a new type of geological formation after analyzing them, combining the ingredients and processes that the Earth has used to produce rocks for billions of years with a new ingredient: plastic pollution.

Santos said they have determined that humans now function as a geological agent, impacting previously entirely natural processes, such as rock formation. She noted that it fits the idea of the Anthropocene in which the geological era of humans influencing Earth's natural processes happens. Plastic rocks will be preserved in the geological record and will mark Anthropocene.

She told Reuters that the location where the rocks with the plastic melted into them were discovered is a "permanently preserved area in Brazil," and the plastic is mostly fishing nets, a common type of debris found on Trinidade's beaches. When the temperature rises, the nets melt into the rocks, resulting in odd plastic rocks.

The discovery prompts scientists to look at how extensive humanity's legacy on Earth has spread, how it affects geological instances, and even the conservation of endangered animals, like green turtles. As plastic pollution continues to worsen, it puts the lives of animals at high risk. These plastic rocks are just one example of how things are going wrong.

A Paradigm Shift for Rock Formation

In the study titled "Plastic debris forms: Rock analogues emerging from marine pollution," published in the journal Marine Pollution Bulletin, Santos and her colleagues classified the new plastic rocks found worldwide into different types. These are "plastiglomerates," which are similar to sedimentary rocks; "pyroplastics," for clastic rocks; and "plastistones," identical to rocks formed by lava flow.

The team wrote that marine pollution triggers a paradigm shift for rock and sedimentary formation. Human interventions are now so pervasive that it questions what truly is natural.

Aside from the fishing nets, there is also an abundance of bottles, household waste, and other plastic trash from around the world found n the island. Santos said she is focusing on this topic for her research given how vulnerable the place is to the trash contaminating the oceans that have led to the formation of plastic rocks.

Here's a video of Santos' interview with Reuters explaining the plastic rocks:

Check out more news and information on Plastic Pollution in Science Times.