Static Compression of CO2-bearing Silicate Liquids

该奖项是根据2009年美国复苏和再投资法案（公法111 - 5）资助的。这项研究的重点是二氧化碳在地球内部深处的高压下溶解时如何与岩浆发生物理相互作用的问题。将测量的主要物理性质是在广泛的压力和温度范围内含有不同数量二氧化碳的压缩岩浆的密度。最终目标是确定二氧化碳改变岩浆密度的程度，从而揭示含二氧化碳的岩浆相对于周围岩石的浮力有多容易。这些实验将大大提高我们预测岩浆上升到地球表面并作为熔岩喷发或形成火山向地球大气层排放二氧化碳和其他气体的条件的能力。实验数据还将提供新的见解，了解二氧化碳等气体是如何被封存在地球岩石深处的，以及在早期地球形成阶段有多少气体被脱气。这项工作采用的实验技术涵盖了地球上地幔熔融和岩浆产生的整个压力和温度条件范围，该项目的实验将允许在活塞-圆筒和多砧装置中使用下沉/浮动方法确定硅酸盐熔体中CO2的偏摩尔体积作为压力和熔体成分的函数，最高可达20 GPa。实验将揭示压力对硅酸盐熔体的影响作为碱金属（K，Na）和碱土金属（Ca）阳离子浓度的函数的任何非理想性。实验还将被设计为提供关于不同合成环境对硅酸盐熔体中的CO2偏摩尔体积和CO2溶解度的影响的信息。建议使用傅里叶变换红外光谱（FTIR）、二次离子质谱（SIMS）和电子探针（EMP）改进定量分析技术，以验证和表征实验运行产品中的CO2总量。在准备该项目时，该团队对碳酸化橄榄岩部分熔体进行了试点研究，以证明这些实验技术将有很高的成功可能性。该项目的结果将有助于建立一个实验基础和新的数据库，用于预测模型，用于计算任何给定的碳酸化硅酸盐熔体成分的密度，这些硅酸盐熔体成分可能是由行星地幔熔化产生的。在高压下的新密度数据也将用于评估状态方程的预测能力，例如Birch-Murnaghan和Vinet方程，在计算高压和高温下含挥发性硅酸盐液体的密度。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This research focuses on the problem of how carbon dioxide physically interacts with magma when dissolved under very high pressures in the Earth's deep interior. The main physical property that will be measured is the density of compressed magma with varying amounts of carbon dioxide under a wide range of pressure and temperatures. The ultimate goal is to determine the degree to which carbon dioxide alters the magma density, thus revealing how readily CO2-bearing magmas will become buoyant relative to surrounding rock. The experiments will greatly improve our ability to predict the conditions under which magmas rise to the Earth's surface and erupt as lavas or form volcanoes that emit carbon dioxide and other gases into Earth's atmosphere. The experimental data will also provide new insight into the way in which gases such as carbon dioxide were sequestered deep in the rocky part of our planet and how much was degassed from the early Earth during its formation stage. This effort employs experimental techniques that span the entire range of pressure and temperature conditions that exist for melting and magma production in the Earth's upper mantle.The experiments in this project will allow the determination of the partial molar volume of CO2 in silicate melts as a function of pressure and melt composition using the sink/float method in piston-cylinder and multi-anvil devices up to 20 GPa. The experiments will reveal any non-ideality in the pressure effect on silicate melt as a function of alkali metal (K, Na) and alkaline earth metal (Ca) cation concentration. The experiments will also be designed to provide information about effects of different synthesis environments on CO2 partial molar volume in silicate melt and CO2 solubility. It is proposed to refine quantitative analysis techniques to verify and characterize CO2-total in the experimental run products using Fourier Transform Infrared Spectroscopy (FTIR), Secondary Ion Mass Spectrometry (SIMS), and the Electron Microprobe (EMP). In preparation for this project, the team carried out a pilot study on carbonated peridotite partial melt to demonstrate that these experimental techniques will have a high likelihood of success. The results from this project will help establish an experimental foundation and new database for predictive models used for calculating the density of any given carbonated silicate melt composition that could be produced by melting in planetary mantles. The new density data at high pressure will also be used to evaluate the predictive power of equations of state, such as the Birch-Murnaghan and Vinet equations, in calculating densities of volatile bearing silicate liquids at high pressure and temperatures.