Hotspots in Earth's top layer keep continents afloat

Posted on Sunday, Jul 01 2007 @ 09:02 CEST by Thomas De Maesschalck
Scientists report hot spots in Earth's top layer are keeping the continents afloat:
It has long been known that the continents float atop the denser rock of the underlying mantle, like foam on a hot tub.

It was presumed that this was simply because they are made of lighter types of rock. However, it turns out that about half of the buoyancy on solid Earth is provided by hot spots.

In these warm regions the rock expands from the heat, making it even less dense than would otherwise be the case.

Without the heat, scientists say, even Denver, Colorado—the Mile High City—would be below sea level.
The scientists calculated the difference in elevation for a couple of cities:
  • New York would be 435m below sea level instead of 10m above
  • New Orleans 736m below sea level instead of 0m
  • Chicago 679m below sea level instead of 179m above
  • Las Vegas 1,070m below sea level instead of 610m above
  • Los Angeles 1,145m below sea level instead of 106m above sea level.

  • About the Author

    Thomas De Maesschalck

    Thomas has been messing with computer since early childhood and firmly believes the Internet is the best thing since sliced bread. Enjoys playing with new tech, is fascinated by science, and passionate about financial markets. When not behind a computer, he can be found with running shoes on or lifting heavy weights in the weight room.

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