In situ monitoring of reaction progress during serpentinization of oceanic lithosphere using synthetic fluid inclusions

使用合成流体包裹体原位监测海洋岩石圈蛇纹石化过程中的反应进程

• 批准号: 1459433
• 负责人: Robert Bodnar
• 金额: $ 31.62万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459433&HistoricalAwards=false
• 关键词: situ; monitoring; reaction; progress; during

Few techniques exist where visual observations and compositional measurements can be made of mineral reactions inside natural host minerals in real-time. This research by two investigators at Virginia Tech, one of whom is early career, explores an exciting and potentially transformative new experimental method by which synthetic fluid inclusions, filled with fluids of seawater-like composition, are grown in the laboratory and then held at temperatures and pressures at which important geological mineral reactions occur. In these reactions, secondary minerals precipitate inside the inclusion due to the reaction between the fluid and host mineral. This research targets serpentinization of the ocean crust, which involves the formation of serpentine, a hydrous mineral, and other secondary phases from anhydrous magnesium-rich silicate minerals (olivine, pyroxene,and garnet) that are the primary constituents of seafloor lavas. Serpentinization of ocean crust releases H2O into the mantle which can trigger melting and arc volcanism. It is also linked to the generation of abiotic organic compounds due to the release of hydrogen during mineral reaction. These organic molecules can form the base of the food chain for microbes living in in the ocean crust. Broader impacts of the work include (1) developing new experimental methods and demonstrating their utility, (2) developing the Raman spectroscopic identification of hydrous minerals associated with serpentinization reactions, (3) support of an early career female scientist and a minority graduate student; and (4) creation of podcasts on science in Spanish to inform and excite Hispanic audiences about science and the proposed research. This experimental program will react fluids in minerals at ~280 degrees C for a number of weeks and monitor the dissolution and precipitation reactions that take place in the fluid inclusions as a function of time, temperature, fluid composition, and host mineral composition using a variety of state-ot-the-art analytical techniques that include: microthermometry, Raman spectroscopy, laser ablation inductively coupled plasma mass spectrometry, micro-FTIR (Fourier Transform Infrared) spectroscopy, and FIB-SEM (focused ion beam scanning electron microscopy). An additional research goal is to develop Raman spectroscopy as a tool for the identification of phases associated with serpentinization, including the identification of chrysotile, lizardite, antigorite, and magnetite, as well as the protolith phases undergoing reaction. Results of the experiments will be compared with predictions from thermodynamic models. Successful development of this experimental technique and demonstation of its applicabilty has the potential to impact other fields of science such as pharmachology and materials science where the ability to observe chemical reactions and their rates of reaction in host crystals in real-time may lead to breakthroughs in understanding.

很少有技术可以实时地对天然寄主矿物质内的矿物反应进行视觉观测和组成测量。 弗吉尼亚理工大学的两名研究人员的这项研究是早期职业生涯，探索了一种令人兴奋且潜在的新型实验方法，通过这种方法，该方法在实验室中生长，含有海水样构图的合成液包含物，然后在其温度和压力下持有，并在其上进行了重要的地质矿物质反应。在这些反应中，由于流体和宿主矿物质之间的反应，次级矿物在包容中沉淀。这项研究靶向了海壳的蛇纹石化，涉及蛇状菌，含水矿物质和其他富含无镁镁硅酸盐矿物质（橄榄石，辉石和石榴石）的二次相。 海壳的蛇形化将H2O释放到地幔中，这会引发融化和弧形火山。由于矿物反应过程中氢的释放，它也与非生物有机化合物的产生有关。这些有机分子可以形成生活在海皮中的微生物的食物链的基础。这项工作的更广泛的影响包括（1）开发新的实验方法并证明其效用，（2）开发与蛇纹石反应相关的含水矿物的拉曼光谱鉴定，（3）早期职业女性科学家和少数族裔研究生的支持； （4）创建西班牙语科学播客，以告知和激发西班牙裔观众有关科学和拟议的研究。 This experimental program will react fluids in minerals at ~280 degrees C for a number of weeks and monitor the dissolution and precipitation reactions that take place in the fluid inclusions as a function of time, temperature, fluid composition, and host mineral composition using a variety of state-ot-the-art analytical techniques that include: microthermometry, Raman spectroscopy, laser ablation inductively coupled plasma mass spectrometry,微型FTIR（傅立叶变换红外）光谱和FIB-SEM（聚焦离子束扫描电子显微镜）。另一个研究目标是开发拉曼光谱作为鉴定与蛇形化相关的阶段的工具，包括鉴定石棉，蜥蜴石，抗岩石和磁铁矿，以及正在反应的原石阶段。实验的结果将与热力学模型的预测进行比较。 该实验技术的成功开发和应用程序的脱号有可能影响其他科学领域，例如药理学和材料科学，在这些领域中，观察化学反应及其实时宿主晶体中的反应率的能力可能会导致理解的突破。