Anthropocene cross section
<div>As <b>invasive species</b> spread around the world, they could leave behind abundant fossils that could signal the start of the Anthropocene. One possibility is the Pacific oyster, which has spread globally from the Sea of Japan since the early 1900s. The image to the left shows a pile of shucked oysters at Nahcotta port, Washington. (Image from Wikimedia commons)</div>
<div><b>Concrete</b>, which is exclusively manmade, is the world's most common building material. Much of the concrete currently in existence was produced after 1950. Now, masses of the stuff are buried underground in cities and under houses as concrete foundations. </div>
<div><b>Plastics</b> are lightweight and degrade slowly, making them ideal indicators for the Anthropocene. Big pieces of plastic slowly break down into tiny pieces, which settle on the seafloor. Meanwhile, <a href="http://www.airspacemag.com/daily-planet/plastic-sign-civilization-180951923/?no-ist">campfires on Hawaii’s beaches</a> have already melted plastic trash into nearby sand and rock to form “plastiglomerate.” (Image courtesy of Kelly Jazvac. Photo credit: Jeff Elstone)</div>
<div>Between 1952 and 1964, <b>nuclear testing </b>sent radioactive fallout into the atmosphere, which is recorded as a stripe of plutonium in sediments throughout the world. It will be detectable for at least 100,000 years. (Image from Wikimedia commons)</div>
<div><b>Aluminum</b> was incredibly rare in its pure form until around 1950. Since then, people have extracted around 98 percent of the aluminum now found on Earth. To the left is an image of bauxite, a common source of natural aluminum. (Image from Wikimedia commons)</div>
<div><b>Burning fossil fuels </b>releases soot or “fly ash” into the atmosphere, and those particles are found in lakes throughout the world. They show up at different times in different lakes, starting as early as 1850 in North America and Europe. The signal shows a dramatic global increase beginning around 1950. (Image from <a href="http://pubs.acs.org/doi/full/10.1021/acs.est.5b00543">ES&amp;T</a>) </div>
<div><b>Landfills</b> are dense concentrations of human trash that contain new minerals and other materials. These deposits could compress into forms of rock never seen before in the geologic record.</div>
<div>If Earth is currently undergoing a <b>mass extinction</b>, as some scientists believe, then Anthropocene sediments will host a completely different set of fossils compared to the Holocene. These include the fossils of large animals, such as rhinos and tigers, as well as microscopic fossils like diatoms that are preserved as sedimentary rock. (Image courtesy of Flickr user Jeffrey Rolinc)</div>

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