| Autor: |
Takashi Yoshino, Kenji Hagiya, Shuangmeng Zhai, Akira Yoneda, Sho Yokoshi, Hiroshi Fukui, Daisuke Yamazaki, Akifumi Nozawa, H. A. Chamathni I. Hegoda, Naotaka Tomioka, Takuya Matsuzaki, M. A. Geeth M. Manthilake, Ken-ichi Funakoshi, Eiji Ito, Tomoo Katsura, Mitsuhiro Sugita, Kazuaki Kawabe, Anton Shatskiy |
| Rok vydání: |
2009 |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters. 36 |
| ISSN: |
0094-8276 |
| Popis: |
[1] The volume of MgSiO3 perovskite has been precisely measured at pressures of 19 to 53 GPa and temperatures of 300 to 2300 K by means of in situ X-ray diffraction in a multi-anvil apparatus. The present results indicate the isothermal bulk modulus KT0 = 256(2) GPa and its pressure derivative K′T0 = 3.8(2). The fixed Debye temperature θ0 = 1030 K gives a Gruneisen parameter at ambient pressure γ0 = 2.6(1) and its logarithmic volume dependence q = 1.7(1). The pressure derivative of the isothermal bulk modulus, Anderson-Gruneisen parameter and thermal expansion coefficient at ambient pressure are found to be (∂KT/∂T)P = −0.035(2) GPa/K, δT = 6.5(5), α0 = 2.6(1) × 10−5 + 1.0(1) × 10−8 (T − 300)/K. Thus the thermal expansion coefficient largely becomes smaller with increasing pressure. The adiabatic geotherm would be fairly large, such as 0.41 K/km at a 660 km depth, and becoming smaller with increasing depth. The temperature and adiabatic geothermal gradient at the bottom of the D′ layer would be 2400 K and 0.14 K/km. The buoyancy-driven mantle convection could be very small in the lower part of the lower mantle. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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