MICHAEL MANGA: Recent Refereed Publications
Manga, M. and R. Jeanloz (1996) Implications of a metal-bearing
chemical boundary layer in D" for mantle dynamics,
Geophysical Research Letters, vol. 23, 3091-3094.
At lower mantle conditions, the thermal conductivity of non-metallic
crystals is an order of magnitude lower than that of dense metallic minerals
such as FeO, FeSi and Fe, which may be present in a chemical
boundary layer at the base of the mantle.
Because the core-mantle boundary is nearly isothermal, variations
in the thickness of a metal-bearing layer
induce lateral temperature variations of several hundred
kelvin, which in turn
affect the pattern of mantle convection. Upwellings should
occur where the layer is thickest; the resulting
stability of the metal + silicate layer with respect to the flow may also
stabilize the pattern of mantle convection, and reduce its time-dependence.
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