Will continents reconnect again?

Posted3/17/2014 12:43 PM
  • A map showing what scientists believe the earth looked like 250 million years ago.

    A map showing what scientists believe the earth looked like 250 million years ago. Courtesy of NASA

You wanted to know

Fifth-graders in Andrea Trela's class at Hawthorn Elementary South in Vernon Hills asked, "In millions of years, will the world look like Pangea again?"

Constant shifting has brought the continents together and broken them apart in the billions of years since the Big Bang sparked the existence of Earth.

Pangea was a supercontinent. It was so large that it was the one single land mass on Earth. Pangea was formed about 250 million years ago and broke apart 150 million years ago. Eventually seven continents emerged that still exist today.

The science behind the idea of land masses breaking apart and reconnecting is called plate tectonics.

About 100 years ago, Meteorologist Alfred Wegener closely examined a map of the world and realized all the continents looked like giant puzzle pieces. The outline of one continent matches the shape of another. India's coastline seems to fit into Asia's borders and Africa aligns with South America.

Layers below the Earth's surface experience heating, cooling and pressure. This creates a bumpy underside for the giant landforms and forces them to move with their supporting plates.

Geologists identified seven major plates, and many smaller plates that rumble and roust constantly, moving continents and parts of ocean basin or both. When plates separate or move closer, the visible evidence at the Earth's surface is earthquakes, volcanic eruptions and upward shift of mountains.

In 50 million years, scientists believe Africa and Europe will link, the Mediterranean Sea will disappear, and the Americas will shift west of their current location.

No one knows for sure, but the data point to the continents eventually reconnecting in 250 million years as one super continent called Pangea Ultima, coming full circle in the supercontinent cycle.

Why study plate tectonics? Experts use seismographs, tools that record movement, to better understand how and why the Earth's land masses have shifted and will continue to push and pull. They drop seismographs onto the ocean floor and use other imaging devices to record movement.

Gail Christeson at the University of Texas studies the Earth's crust and lower layers called the crustal structure. Christeson's research centers on the giant 12-mile-deep by 110-mile-wide dent in the Yucatán Peninsula that was created by a massive meteorite when it slammed into the Earth 65 million years ago.

"This information lets us know the dimensions of the resulting crater, and from there other scientists can do modeling to understand the environmental consequences of such a large impact. Other places I study are linked more directly to plate tectonics," she explained.

Christeson's work is used to understand the results of the plate tectonic processes on various regions of the world.

The Earth is not alone as a planet with moving crustal structures. Mars has plate tectonics, too. Planetary geologist An Yin announced two years ago that Mars is at the beginning stages of plate movement. This research will expand scientists' knowledge of how geological processes work on Earth.

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