The geology of Brazil’s volcanic island of Trindade has fascinated scientists for years.
Located about 1,150 kilometers east of Vitória (capital of the state of Espírito Santo), Ilha da Trindade (Island of the Trinity) is an active stratovolcano with craters and numerous lava domes.
The discovery of rocks made of plastic waste on this remote turtle refuge is now raising alarm bells.
The melted plastic has mixed with rocks, which researchers believe is evidence of the growing influence of humans on Earth’s geological cycles.
“This is both new and scary because pollution has reached geology,” said Fernanda Avelar Santos, a geologist at the Federal University of Paraná.
Santos and her team conducted chemical tests to find out what plastics are in the rocks, called “plastiglomerates” because they are a mixture of sediment granules and other debris held together by plastic.
“We found that the pollution comes mainly from fishing nets, which are very common on the beaches of Trinidade Island,” Santos said.
“The ocean currents carry the nets and accumulate on the beach. When the temperature rises, this plastic melts and becomes encrusted with the natural beach material.”
Trindade Island is one of the most important places in the world for the protection of the green sea turtle (Chelonia mydas), where thousands of turtles gather each year to lay their eggs. T
The only human residents of Trindade are members of the Brazilian Navy, which maintains a base on the island and protects the nesting turtles.
“The place where we found these (plastic) samples is a permanently protected area in Brazil, near where the green turtles lay their eggs,” Santos explains.
“We are producing more single-use plastic waste than ever before, and the discovery raises questions about man’s legacy on Earth,” Santos said.
“Pollution, trash in the ocean, and improperly disposed of plastic in the oceans are becoming geological material … preserved in the Earth’s geological record,” she adds.
ANTHROPOCENE: THE AGE OF HUMAN-INDUCED CONSEQUENCES IN GEOLOGIC TIME
The most important contribution of the article is recognizing that humans are emerging as geologic actors, influencing sedimentary deposits. In light of human intervention, the authors warn that it is necessary to question what is truly natural.
For researcher and co-author Giovana Diório, a master’s student in geology at UFPR, the current human behavior concerning marine pollution is leading to a paradigm shift in classical geology, which takes a pre-Anthropocene perspective, that is, understanding the ancient processes of Earth’s history from a view based on the time before significant human intervention in natural processes.
“Occurrences show that the influence of humans and their residues are so present in the environment that they began to affect processes that were previously considered essentially natural, for example, the formation of rocks,” Giovana continues.
“Throughout geologic time, the main factors that changed the Earth’s record were natural—for example, tectonic processes and climate changes. However, in modern times, human activity is so pervasive that it is changing the planet faster than natural processes,” the article’s lead author explains.
She cites an example: “If we destroy mountains to mine minerals or build roads, that mountain can be eroded within weeks or a few years. This process would take thousands or millions of years with natural erosion.”
The process of forming a rock by marine pollution, for example, is rapid and depends on three phases in which humans act as the main actor in geology.
Availability of plastic waste in the marine or coastal environment; arrangement and deposition of the waste in a place on the beach, which happens when people collect the waste to dispose of it or build a fire; and increase in the temperature of the environment due to the fire, causing the plastic to melt and interact with the sediments of the beach, creating plastic cement and consequently these rocks.
For geologist Carlos Conforti Ferreira Guedes, professor at the UFPR Geology Department and collaborator on the published article, it is necessary to record human impact on the Earth stratigraphically.
The sedimentary and stratigraphic analysis is the study and description of sediments and sedimentary rocks to interpret how they were formed.
He explains that non-natural materials such as trash and plastics, which occur randomly in nature, participate in sedimentary processes and accumulate alongside classic rocks, and are preserved in what is known as the geologic record.
“When future geologists analyze the rocks of this period, they will be able to see the impact of humans on the Earth by identifying these non-natural materials alongside the natural materials,” he says.
Although it is not yet possible to define the environmental impact of these rocks composed of synthetics and their behavior in the geologic record, Fernanda suggests that geosciences are beginning to consider human actions and anthropogenic materials as fundamental attributes in recent processes.
“Currently, in classical geology concepts, only natural factors are considered predominant to define terms, such as the definition of rock. From an Anthropocene perspective, these criteria must be updated to include human activity as a fundamental aspect.”
“In this way, we will be able to understand how we are affecting the current terrestrial system and look for solutions to mitigate the impact and build a geological future in harmony with natural systems,” warns the scientist.
Human impact on planet Earth is the research area of the Anthropocene, a perspective that describes the time when humans become active geological actors in current geological processes.
Geologic time, which underlies important fundamental theories of modern science – such as the theory of evolution – represents the recognition of a chronological scale that divides the 4.5 billion years of Earth’s history and is critical to understanding the planet’s evolution from its beginnings to what we know today.
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This article was produced by The Rio Times’ automated newsroom system. How we use AI · Report an error · Editorial responsibility: Matthias Camenzind, Editor-in-Chief