An Experimental Study of Solubility, Solution Mechanisms, and Stable Istope Fractionation of COHN Volatiles in Silicate Melts and Fluids in the Earth's Interior

智力上的优点。描述控制挥发物(H2O、CO2、CO、CH4、N2、NH3、惰性气体等)行为和预算的过程对于我们理解固体地球、海洋和大气的形成和演化是非常重要的。对地球内部熔融和结晶的物理化学描述是这一理解的核心。挥发分在硅酸盐熔体中的溶解度和溶解机理的实验表征，以及挥发分在凝聚相和气相之间的分布和稳定同位素分馏是这一知识库的重要组成部分，并构成了拟议研究的核心。提出了一项研究计划，以实验确定(I)C-H-O-N体系中挥发物在硅酸盐熔体中的溶解度和溶解机理，作为主体组成、温度、压力和氧化还原条件的函数，并特别强调还原物种，以及(Ii)在地幔压力和温度下，溶解在硅酸盐熔体和共存气体中的氮和碳之间的同位素分馏，作为挥发物在熔体和共存气体中形态的函数。初步实验数据表明，这项工作将对核形成、地球演化、不稳定的预算和脱气过程产生深远的影响。拟议的工作将提供有关简单硅酸盐熔体系统熔体结构的信息，并根据需要扩展到更复杂的化学系统(包括含铁)。这些性质将作为组成、压力、温度和氢逸度的函数来确定。结构研究将通过拉曼光谱、穆斯堡尔谱和傅里叶变换红外光谱进行。熔体和共存气体的化学和同位素分析将用电子探针、气相色谱和质谱仪进行。除PI外，在拟议研究的3年期间，拟议的研究方案将平均涉及1-2名博士后研究人员和2名本科生和高中实习生。学生和博士后将参与实验项目的执行，并将实验结果应用于岩石形成过程的表征。因此，它们将有助于实现拟议研究的目标。此外，PI与地球内部研究所(日本三沙市Isei)和地球物理研究所(法国巴黎)的研究人员之间的持续国际合作将进一步帮助拟议的研究计划。特别是，地球物理实验室和国际地球物理研究所的研究人员之间的合作将是成功完成拟议项目的关键。

Intellectual merit. Characterization of the processes that govern the behavior and budget of volatiles (H2O, CO2, CO, CH4, N2, NH3, noble gases, etc.) in the Earth's interior is fundamental to our understanding of the formation and evolution of the solid Earth, its oceans, and atmosphere. Physicochemical description of melting and crystallization in the Earth's interior is central to this understanding. Experimental characterization of solubility and solution mechanisms of volatiles in silicate melts, and the distribution and stable isotope fractionation of volatile components between condensed and gaseous phases are important components of this knowledge base and form the core of the proposed research. A research program is proposed to experimentally determine (i) the solubility and solution mechanisms in silicate melts of volatiles in the C-H-O-N system as a function of bulk composition, temperature, pressure, and redox conditions with particular emphasis on reduced species, and (ii) isotope fractionation between nitrogen and carbon dissolved in silicate melts and in coexisting gas at mantle pressures and temperatures as a function of speciation of the volatiles in melt and coexisting gas. Preliminary experimental data suggest that this work will have profound implications for core-formation, the Earth's evolution, volatile budget, and degassing processes. The proposed work will provide information on melt structure of simple silicate melt systems with expansions to more complex chemical systems (including Fe-bearing) as needed. These properties will be determined as a function of composition, pressure, temperature, and hydrogen fugacity. Structural studies will be conducted via Raman, Mossbauer, and FTIR spectroscopy. Chemical and isotopic analyses of melts and coexisting gas will be carried out with the electron microprobe, gas chromatography, and mass spectrometry.Broader impacts. In addition to the PI proposed research program will involve on the average 1-2 post-doctoral researchers and 2 undergraduate and high school interns during the 3-year period of the proposed research. The students and post-docs will be involved in execution of experimental projects and in the application of the experimental results to characterization of rock-forming processes. They will, therefore, aid in reaching the goals of the proposed research. In addition, continuing international collaboration between the PI and researchers from the Institute for the Study of the Earth's Interior (ISEI, Misasa, JAPAN) and Institut de Physique du Globe (Paris, FRANCE) will further aid the proposed research program. In particular, collaboration between researchers at the Geophysical Laboratory and at ISEI will be central to the successful completion of the proposed project.