P-V-T relations of MgSiO3 perovskite determined by in situ X-ray diffraction using a large-volume high-pressure apparatus
P-V-T relations of MgSiO3 perovskite determined by in situ X-ray diffraction using a large-volume high-pressure apparatus
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DOI：
10.1029/2008gl035658
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发表时间：
2009-01-07
影响因子：
5.2
通讯作者：
Funakoshi, Ken-ichi
中科院分区：
文献类型：
--
作者：
Katsura, Tomoo;Yokoshi, Sho;Funakoshi, Ken-ichi
在压力为19 ~ 53 GPa、温度为300 ~ 2300 K的条件下，用多砧装置原位X射线衍射法精确测量了MgSiO_3钙钛矿的体积。结果表明，该合金的等温体积弹性模量K-T_0 = 256（2）GPa，压力导数K-T_0 ' = 3.8（2）。固定的德拜温度θ（0）= 1030 K给出了环境压力下的Gruneisen参数γ（0）= 2.6（1）和其对数体积依赖性q = 1.7（1）。在常压下，等温体积弹性模量、Anderson-Gruneisen参数和热膨胀系数的压力导数为（偏导数K-T/偏导数T）（P）= -0.035（2）GPa/K，δ（T）= 6.5（5），α（0）= 2.6（1）× 10（-5）+ 1.0（1）× 10（-8）（T - 300）/K。因此，随着压力的增加，热膨胀系数大大减小。绝热地热会相当大，例如在660 km深度处为0.41 K/km，并且随着深度的增加而变小。D'层底部的温度和绝热地温梯度分别为2400 K和0.14 K/km。在下地幔下部，浮力驱动的地幔对流可能很小。引文：Katalina，T.，等人（2009），使用大体积高压装置通过原位X射线衍射确定的MgSiO 3钙钛矿的P-V-T关系，Geophys. Res. Lett.，36，L01305，doi：10.1029/2008GL035658。
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 K-T0 = 256(2) GPa and its pressure derivative K-T0' = 3.8(2). The fixed Debye temperature theta(0) = 1030 K gives a Gruneisen parameter at ambient pressure gamma(0) = 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 (partial derivative K-T/partial derivative T)(P) = -0.035(2) GPa/K, delta(T) = 6.5(5), alpha(0) = 2.6(1) x 10(-5) + 1.0(1) x 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. Citation: Katsura, T., et al. (2009), P-V-T relations of MgSiO3 perovskite determined by in situ X-ray diffraction using a large-volume high-pressure apparatus, Geophys. Res. Lett., 36, L01305, doi: 10.1029/2008GL035658.