There are multiple types of these plastic-rock hybrids. Plastistones are formed when plastic melts and bonds with existing rocks. Plastistone is used as an “umbrella term” for these plastic and rock mixtures. Other categories of plastistones include plastiglomerates, which are rocks made from sedimentary particles and other debris held together by melted plastic. First discovered on Kamilo Beach in Hawaii, these rocks usually contain larger identifiable pieces of waste, both plastic and other. These can often be picked up and broken apart.
Pyroplastics are similar to plastiglomerates in that they are both formed with melted plastic, but they tend to be much smaller in size and lack the large debris. These types of plastistones can often be found alongside plastiglomerates.
Another type, plasticrust, is formed when plastic waste in the ocean is smashed against existing rock faces and begins to adhere. The creation of plasticrusts is directly related to the amount of plastic waste in the water and tidal patterns.
Finally, anthropoquina is a type of sedimentary rock formed through cementation that contains pieces of plastic waste and other materials, both man-made and natural.
The existence of plastistones signals an intersection between natural processes and the impact of human activities on our environment. Since plastic cannot decompose, nature has found a way to integrate it into its natural processes. This may sound like a positive thing, but it most certainly is not. The introduction of plastistones into ecosystems has caused many issues for native wildlife. Just like regular rocks, some of these eventually erode, but they are leaving microplastics in place of sand. These microplastics then enter the food chain, leading to many issues for the wildlife, like the bioaccumulation of toxins, malnutrition, and eventually death.
It is important to remember that humans are a part of that food chain too, and eventually this will come to affect us all. In fact, according to Stanford University Medical Center, human consumption of microplastics is equal to “one credit card a week”. This is an issue that will continue to get worse exponentially.
Similar to how fossils help geologists and historians decipher the past, these technofossils will act as geographical evidence of human existence. These rocks are considered a marker of the Anthropocene, a reminder of human pollution literally etched into the Earth.
