Tuesday, August 14, 2007

Plate Tectonics

Curious article on plate tectonics - apparently the Earth releases more internal heat when the crust is made up of several smaller tectonics plates than when the crust is made up of one large one, which intuitively makes sense, but hasn't been supported by any evidence up to this point.

"The reason, the authors said, is that much of the heat from the mantle escapes near the ridges between newly formed plates. Those areas are thinner and allow more heat to pass.

The smaller the plates, the greater the heat loss from the mantle on which they float, said geophysicists from the University of Southern California, Johns Hopkins University and the University of Michigan at Ann Arbor.

Several small plates have more area close to the ridge -- and allow more heat to pass -- than one large plate, explained lead author Thorsten Becker, assistant professor of earth sciences at USC."

In addition, the study found that having several smaller plates also caused a greater amount of tectonic activity (also pretty intuitive) - with more plates rubbing on one another, more events are likely to happen. However, there is one issue that can't yet be explained - at both the rate of the Earth's heat disappation previously believed to have occurred, as well as these new higher figures, the Earth would have been impossibly hot in the distant past when the planet was formed. ???

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