Recent laboratory work  suggests that the thermal expansivity α of the mantle decreases strongly with pressure. α determines the buoyancy of plumes and the rate at which plumes lose their thermal signature as they rise, and so may be expected to have a strong influence on the temperature and velocity structure of the mantle. Numerical simulations were conducted on convection in an internally heated, compressible mantle including constant and pressure-dependent α and thermal conductivity k. They show that a pressure-dependent α allows the existence of thermal plumes rising from the core-mantle boundary (CMB), however the plumes are weak and dissipate higher in the mantle.
|Original language||English (US)|
|Number of pages||20|
|Journal||Earth and Planetary Science Letters|
|State||Published - Feb 1991|
Bibliographical noteFunding Information:
The authors would like to thank Dr. R. Boehler and Prof. V. Zharkov for helpful discussions and C. Lausten for her excellent technical assistance. Research was supported by NSF grant EAR-8817039 and N.A.S.A. Geodynamic Program.