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) presented at the
2002 meeting of the American Geophysical Union.
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