Chemical mixing in present day Earth.
See 
"Mixing in a 3D spherical model of present day mantle convection", 
Peter van Keken and Shijie Zhong, Earth Plan. Sci. Lett. 171, 533-547, 1999. 
(http://www.geo.lsa.umich.edu/~keken/papers/EPSL.99/epsl99.html).

sausages_cartMantFlow.tar.gz
sausages_sphereMantFlow1.tar.gz
sausages_sphereMantFlow2.tar.gz
   Simple representations using a few tracers
indian.tar.gz
   Mixing of the Indian plate
nazca.tar.gz
   Mixing of the Nazca plate