Temperature profile in the lowermost mantle from seismological and mineral physics joint modeling.
The internal structure of the core-mantle boundary (CMB) region of the Earth plays a crucial role in controlling the dynamics and evolution of our planet. We have developed a comprehensive model based on the radial variations of shear velocity in the D'' layer (the base of the lower mantle) and the high-P,T elastic properties of major candidate minerals, including the effects of post-perovskite phase changes. This modeling shows a temperature profile in the lowermost mantle with a CMB temperature of 3,800 +/- 200 K, which suggests that lateral temperature variations of 200-300 K can explain much of the large velocity heterogeneity observed in D''. A single-crossing phase transition model was found to be more favorable in reproducing the observed seismic wave velocity structure than a double-crossing phase transition model.
Kawai
Kenji
K
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro, Tokyo 152-8551, Japan. kenji@geo.titech.ac.jp
Tsuchiya
Taku
T