Noble Gas Fractionation During Degassing: A Proof-of-Concept High-Pressure Experimental Study

脱气过程中的惰性气体分馏：概念验证高压实验研究

• 批准号: 1029317
• 负责人: Stephen Parman
• 金额: $ 5.77万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1029317&HistoricalAwards=false
• 关键词: Noble; Gas; Fractionation; During; Degassing

Earth's atmosphere originated from degassing of the planet's interior over time and release of these gases, some of which are greenhouse intensive (CO2, H2O, and S), continues to this day via igneous processes. Because we have no way to quantify now much of the magmatic volatile load is lost during the eruptive process and how much remains trapped in volcanic rocks. This prevents adequate estimates of gas contributions to greenhouse and other atmospheric gases by submarine volcanism. This research is a pilot study to examine the utility of a novel new experimental and analytical approach for determining magma degassing using noble gases (He, Ne, Ar) and their isotopes and CO2. This research develops new bubble growth/gas fractionation experiments in which synthetic seafloor volcanic glasses will be synthesized at high temperatures and pressures from oxide powders in internally heated pressure vessels. The composition of the glasses will be modified so they are clear so bubbles and bubble size distributions can be measured optically. Glasses will then be remelted and infused with volatiles at high pressure and then exposed to a constant rate of decompression allowing bubbles to form. Glasses and the volatile compositions of the bubbles will be analyzed for He, Ne, Ar, and CO2. Bubble compositions will be analyzed using an excimer laser and FTIR. Results of the work should dramatically improve out understanding of the magma degassing process and rate of volatile input from the mantle to the oceans and atmosphere. Broader impacts of the work include developing new experimental methodology that will increase the infrastructure for science. The project also involved international collaboration with a French scientist and will train a graduate student who will cross-train in the French collaborator's laboratory. The work supports an early career faculty member at an institution in an EPSCoR state.

地球大气层起源于地球内部随着时间的推移脱气和释放这些气体，其中一些是温室密集型的（CO2、H2O和S），这些气体通过火成过程持续至今。因为我们现在无法量化在喷发过程中损失的岩浆挥发量以及有多少残留在火山岩中。这阻碍了对海底火山活动对温室气体和其他大气气体的贡献的充分估计。这项研究是一项试点研究，旨在检验一种新颖的实验和分析方法的实用性，用于使用稀有气体（He、Ne、Ar）及其同位素和 CO2 确定岩浆脱气。这项研究开发了新的气泡生长/气体分馏实验，其中合成海底火山玻璃将在高温高压下由内部加热压力容器中的氧化物粉末合成。 玻璃的成分将被修改，使其变得透明，从而可以光学测量气泡和气泡尺寸分布。然后，玻璃将被重新熔化并在高压下注入挥发物，然后暴露在恒定的减压速率下，从而形成气泡。 将分析玻璃和气泡的挥发性成分中的 He、Ne、Ar 和 CO2。 将使用准分子激光和 FTIR 分析气泡成分。 这项工作的结果将极大地提高人们对岩浆脱气过程以及从地幔到海洋和大气的挥发性输入速率的理解。 这项工作的更广泛影响包括开发新的实验方法，以增加科学基础设施。该项目还涉及与一位法国科学家的国际合作，并将培训一名研究生，后者将在法国合作者的实验室进行交叉培训。这项工作为 EPSCoR 州某机构的一名早期职业教员提供支持。