硅酸盐熔体中的水

发布时间：2018-07-03 15:58

本文选题：硅酸盐熔体 + 水　；参考：《矿物岩石地球化学通报》2017年01期

【摘要】：水是地球岩浆中的一种主要挥发分。水的存在导致岩石的熔融温度降低,其根本原因在于水易溶于硅酸盐熔体。本文总结了在地球岩石圈温压条件下,水在硅酸盐熔体中的赋存形式、溶解度与水对熔体物理性质的影响。熔体中溶解的水以H_2O分子和OH形式存在。水在熔体中的溶解度随压力的升高而增大。当温压条件位于含水硅酸盐体系的临界曲线之上时,甚至可能形成成分介于硅酸盐熔体和富水流体之间的超临界流体。水使熔体的密度和黏度降低,更易于脱离源区向上运移。水使元素扩散加快,有利于晶体和气泡的生长。水导致熔体的电导率升高,使部分熔融造成的电导率异常更加显著。水对硅酸盐熔体迁移性质的影响以及水的溶解行为都与水的种型分异反应密切相关。在研究与熔融有关的地质过程时必须充分考虑水的作用。
[Abstract]:Water is a major volatilization in the magma of the earth. The existence of water leads to the decrease of the melting temperature of rock, and the fundamental reason is that the water is soluble in silicate melt. In this paper, the occurrence of water in silicate melt under the condition of lithosphere temperature and pressure, the influence of solubility and water on the physical properties of the melt are summarized. The dissolved water in the melt exists in the form of H _ 2O and OH. The solubility of water in the melt increases with the increase of pressure. When the temperature and pressure conditions are above the critical curve of the aqueous silicate system, even supercritical fluids with compositions between silicate melts and water-rich fluids may be formed. Water reduces the density and viscosity of the melt and makes it easier to move upward from the source area. Water accelerates the diffusion of elements and facilitates the growth of crystals and bubbles. Water increases the electrical conductivity of the melt and makes the electrical conductivity of partial melting more remarkable. The effects of water on the migration properties of silicate melts and the dissolution behavior of water are closely related to the species differentiation reaction of water. The role of water must be fully taken into account in the study of geological processes related to melting.
【作者单位】：中国科学院壳幔物质与环境重点实验室中国科学技术大学地球和空间科学学院;
【基金】：国家自然科学基金项目(41590622) 中组部“青年千人计划”项目
【分类号】：P592

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