Convection in the Earth's Mantle

This animation shows how the hot silicate rock of the Earth's mantle is stirred by heat trying to escape. The heat is generated by the radioactive decay of natural elements like uranium. The hot rock (yellow) rises slowly as the denser cold rock (blue) sinks. The layer is at least 700 km thick, and could be as thick as 2900 km. The rock is at temperatures of order 1000 to 2000°C and creeps like a very viscous fluid. Its viscosity is about 20 orders of magnitude greater than that of water so velocity is only centimeters per year, and the time interval of this animation is of order 10 million years.

These calculations are made with the thermal convection program "tdcon" written by the author.

View the poster "Convection beneath Continents" (a 2.24 Mb jpeg file) recently presented at the 2002 meeting of the American Geophysical Union.
 

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