Adiabatic temperature profile in the mantle

Determination of thermal expansivity of the mantle minerals

Temperature is the most fundamental parameter to discuss the dynamics of the Earth's interior. Nevertheless, the temperature distribution in the deep mantle is not well constrained. The mantle geotherm is considered nearly adiabatic, because heat is mainly transferred by convection in the majority of the mantle. The adiabatic temperature gradient is given by:

 (dT/dz)S = αgT/CP

where α is the thermal expansivity, g is the gravity acceleration, CP is the isobaric heat capacity. Since the gravity acceleration and isobaric heat capacity in the mantle do not vary largely, the thermal expansion coefficient is a key parameter to estimate the temperature distribution in the deep mantle. we determined thermal expansion coefficient of mantle minerals under conditions realistic for deep mantle.



New apparatus

P-V-T measurement

Re-evaluation of temperature at the 410-km discontinuity

Adiabatic temperature distribution

Appendix: Table of the geotherm