Plastiglomerate forming a marker horizon in sediment layers

Plastiglomerate is a rock made of a mixture of sedimentary grains, and other natural debris (e.g. shells, wood) that is held together by plastic. It has been considered a potential marker of the Anthropocene, an informal epoch of the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

proposed by some social scientists, environmentalists, and geologists.

Origin

Plastiglomerates form along shorelines where natural sedimentary grains and organic debris are agglutinated by melted plastic. They can be created during campfire burning, as has been reported from Kamilo Beach on the island of Hawaii, or during hot weather, as is the case on

Trindade Island Trindade and Martim Vaz ( pt, Trindade e Martim Vaz, ) is an archipelago located in the South Atlantic Ocean about east of the coast of the Brazilian state of Espírito Santo, of which it forms a part. The archipelago has a total area of and a ...

Depositional environment

Plastiglomerate could potentially form a marker horizon of human pollution on the geologic record. and may survive as future fossils. Plastiglomerate may also conceivably form in plastic-polluted regions affected by

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...

s or

forest fire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

s. They have been found on the surface as well as beneath the sand. This suggests that plastiglomerates are being actively deposited into the sedimentary record. Some geophysicists and geologists speculate that plastiglomerates will not persist in the fossil record, however, or that they might " to a source of oil from whence they came, given the right conditions of burial". "In situ" plastiglomerate forms where plastic melts and fills in rock cavities. "Clastic" plastiglomerate are smaller solitary pieces that form where larger fused items become fragmented by waves. Plastiglomerate is denser than particles that are solely composed of plastic, which gives them greater potential to become buried and preserved in the rock record. Plastiglomerate Museon

Plastiglomerates have been featured at the Yale Peabody Museum of Natural History; Oakville Galleries in Oakville, Ontario, Canada; Louis B. James Gallery in New York City; Carleton University Gallery in Ottawa, Ontario, Canada; Prosjektrom Normanns, Stavanger, Norway; and Museon in The Hague, Netherlands. Museon claims to have probably the largest piece of plastiglomerate, which is more than 1m long and 50cm wide.

History

Charles Moore, a sea captain and oceanographer for the Algalita Marine Research Institute in Long Beach, California, discovered this substance in 2006 while surveying

Kamilo Beach Kamilo Beach (literally, ''the twisting'' or ''swirling currents''Clark, John R. K. (1985), ''Beaches of the Big Island'', University of Hawaii Press, , p. 69 in Hawaiian), is a beach located on the southeast coast of the island of Hawaii. It i ...

on the Big Island of

Hawai’i Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

. Geology professor, Dr. Patricia Corcoran and Visual artist professor, Kelly Jazvac of the University of Western Ontario investigated the samples on Kamilo Beach in 2012 where they also coined the term "plastiglomerate". Approximately one-fifth of the plastiglomerates found at Kamilo Beach of fishing debris, one quarter of broken lid containers, and one half consisted of plastic "confetti". The plastiglomerate at Kamilo Beach was more likely created from human campfires than from molten lava flows. In 2023, it was reported plastiglomerates had been discovered on remote

, a known refuge for turtles.

Origin

Depositional environment

History

See also

References

Further reading