dimarts, 28 de maig del 2013

Trenches








When the subducting plate is bent downward to form a very deep depression in the ocean floor, this is called an Oceanic Trench.










The age of the ocean floor increases as the distance from the ridges increases. The oldest seafloor often ends in the deep-sea trenches.  Like the mid-oceanic ridges, the trenches are seismically active, but unlike the ridges they have low levels of heat flow. 

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