Theoretical models and experimental determination methods for equations of state of silicate melts:A review
Theoretical models and experimental determination methods for equations of state of silicate melts:A review
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硅酸盐熔体状态方程的理论模型和实验测定方法综述
DOI：
10.1007/s11430-017-9325-3
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发表时间：
2019
影响因子：
5.7
通讯作者：
Liu Qiong
中科院分区：
文献类型：
--
作者：
Hou Juntao;Liu Qiong
硅酸盐熔体在地球和其他类地行星内部非常活跃，是物质和能量运输的重要载体。硅酸盐熔体的状态方程（EOS）的确定以及摩尔体积（或密度）与温度、压力和成分之间精确的定量关系的获得，对于模拟地球和其他类地行星形成早期岩浆的产生、迁移和喷发过程以及岩浆海洋阶段的演化，对于计算和模拟涉及硅酸盐熔体的相平衡，以及揭示地球和其他类地行星的演化过程至关重要硅酸盐熔体微观结构随压力的变化。然而，在实验上确定硅酸盐熔体的体积性质具有挑战性，并且由于一系列问题，如：硅酸盐岩石的高液相温度；硅酸盐熔体与样品胶囊反应改变熔体组成的倾向；高压高温实验中熔体流动和泄漏的倾向性。近年来，高压高温实验技术有了长足的发展，不仅温度和压力范围的扩大，而且测量精度的提高，现场测量新方法的出现。本文综述了目前广泛应用的常压和高压硅酸盐熔体热应力理论模型，指出了目前急需解决的问题：(1)含铁和含钛硅酸盐熔体的室温热应力有待改进；(2)含挥发性组分的硅酸盐熔体中H_2O和CO_2组分的偏摩尔性质随熔体成分的不同而变化，这需要在高压EOS中解决；(3) EOS的配方和适用范围如何对应熔体结构和压缩机理的变化，有待进一步研究。重点介绍了各种测定硅酸盐熔体EOS的方法的基本原理和适用范围，比较了双波波阿基米德法、熔合曲线分析法、激波压缩实验法、沉浮法、x射线吸收法、x射线衍射法和超声干涉法的优缺点。未来的发展趋势是发展高温高压下熔体密度或声速的原位测量实验技术，积累更多的实验数据；另一方面，通过对硅酸盐熔体微观结构和压缩机理的研究相结合，完善硅酸盐熔体动力学的理论模型。
Silicate melts are very active in the interior of the Earth and other terrestrial planets,and are important carriers for the transport of material and energy.The determination of the equation of state (EOS) for silicate melts and the acquisition of a precise quantitative relationship between molar volume (or density) and temperature,pressure,and composition is essential for simulating the generation,migration,and eruption processes of magmas and the evolution of the magma ocean stage during the early formation of the Earth and other terrestrial planets,for calculating and modeling the phase equilibria involving silicate melts,and for revealing the variation of the microstructure of silicate melts with pressure.However,it is experimentally challenging to determine the volumetric properties of silicate melts and the accumulated density data at high pressure are still very limited due to a series of problems such as:the high liquidus temperature of silicate rocks;proneness for silicate melts to react with sample capsules to change the melt composition;and proneness for melts to flow and leak during the high pressure and high temperature experiments.In recent years,there is rapid progress in the high pressure and high temperature experimental techniques,in terms of not only the extension of temperature and pressure ranges but also the improvement on the accuracy of measurements,and the emergence of new methods for in-situ measurements.Here,we review the widely-used theoretical models of ambient-pressure and high-pressure EOS for silicate melts,and illustrate some problems that need to be solved urgently:(1) the room pressure EOS for iron- and titanium-bearing silicate melts needs to be improved;(2) the partial molar properties of the H_2O and CO_2 components in silicate melts containing volatile components may vary markedly with the melt composition,which need to be addressed in high-pressure EOS;(3) how the formulation and applicable range of EOS correspond to changes in melt structure and compression mechanism requires further study.We highlight the basic principle and applicable range of various methods for determining the EOS for silicate melts,and compare the advantages and disadvantages of doublebob Archimedes method,fusion curve analysis,shock compression experiments,sink-float method,X-ray absorption,X-ray diffraction and ultrasonic interferometry.Future trends in this field are to develop experimental techniques for in situ measurements on melt density or sound velocity at high temperature and high pressure and to accumulate more experimental data,and on the other hand,to improve the theoretical models of the EOS for silicate melts by a combination of research on the microstructure and compression mechanisms of silicate melts.