Congratulations, humanity: After millennia of building cathedrals and toiling over great works of art and science, we've finally created something that will far outlast us. It's called Plastiglomerate, a stone made out of molten plastic, and yes, we should probably be ashamed of ourselves.
In a study published yesterday in the Geological Society of America, researchers describe how plastic melts into a primordial ooze, fusing with existing sand, coral, shells, and local woody debris. Most plastic in the ocean disintegrates into small pieces (which don't go away, either), but some of it melts into "molten" plastic, and it fuses with all the regular, organic materials below it, forming a super-hard monolithic stone.
It was first observed in Hawaii in 2006 by an oceanographer, but geologists didn't collect the stones until 2012. According to the new study, even though most of the plastic is molten, you can often still identify specific objects within the stone, including "netting/ropes, pellets, partial containers/packaging, lids, tubes/pipes, and 'confetti.'"
How long is this stuff going to last? The New York Times speculates that it will be around longer than we are:
Many scientists believe the planet has entered a new geological era, the Anthropocene, in which human activity is leaving a vast and durable imprint on the natural world. Along with building materials, tools and atmospheric signatures, plastiglomerates could be future markers of humanity's time on earth.