Manmade Rocks - A New Formation!

Jul 17, 2014 By Akila, Young Editor
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Remember the Pacific Garbage Patch, garbage gyros and the plastic accumulation in our landfills?

Now think also about the different rock groups you already know about. Sedimentary, Metamorphic and Igneous - right? Be prepared to add one more rock type to the mix soon!

Scientists in Hawaii have discovered a new type of rock on Kamilo Beach - one of the dirtiest beaches in the world. Called ‘Plastiglomerates’, these rocks appear to have some plastic material mixed with smaller rocks, coral and other surrounding material. They appear similar to Igneous rocks - rocks formed through volcanic activity.

Though initially noticed by oceanographer Charles Moore in 2006, it is only recently that researchers and scientists are taking the matter seriously and studying the rocks closely.

Creating Plastiglomerate

Igneous rocks are formed from magma when volcanoes erupt. Under the surface of the Earth, the magma is in a liquid form at high temperatures and pressure. On reaching the surface, however, it rapidly cools down and solidifies into rocks.

In the active volcanic region of Hawaii, now imagine the presence of swirling bits of plastic debris in the ocean waters. As the lava emerges, it gathers other material that it comes upon. Plastic trash washed up by ocean currents, melts and fuses together with the hot lava resulting in a plastic-rock mixture. 

Scientists have been puzzled at the discovery of plastiglomerates on coastlines far away from actual volcanic activity -- not just in Hawaii but also on land and coasts around the world. They are studying the effect of oceanic currents in spreading this new form of rock to places far away from where they are created.

Plastic rocks form when molten plastic fuses with other rock-like materials. Fires lit by humans at campsites, forest fires and even extreme temperatures can act as triggers to melt plastic.

Researchers have classified plastiglomerates into two types - 'in situ' and clastic. 'In Situ' is the kind of plastic that bonds to rock outcrops while 'clastic' is composed of plastic, volcanic ash, rock, beach sand, seashells and corals. 

The Impact On Our Environment

We know plastic takes thousands of year to break down. Heavy human use of this material in recent times has caused this extremely versatile material to find its way from useful household items to trash. Discarded plastic waste is an eyesore in landfills and sometimes even on main streets in developing countries.

Soon we may find that plastic will be part of the very soil that feeds us. Consider its impact on our plant food chain. The other issue with plastic rocks in oceans is that, being dense, these rocks tend to sink to ocean floors and disrupt marine life.

Human activity is starting to disrupt even geological activity. Certainly plastic is not disappearing from our earth in a hurry, and this may be just one more way that ensures plastic is going to stay with us for a lot longer!

Courtesy: Scientific American, LiveScience