Accomplishment Based Renewal: Experimental Studies of the PTX Properties of Immiscible Fluids at Crustal PT Conditions

基于成果的更新：地壳 PT 条件下不混溶流体的 PTX 性质的实验研究

• 批准号: 0711333
• 负责人: Robert Bodnar
• 金额: --
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0711333&HistoricalAwards=false
• 关键词: Accomplishment; Based; Renewal; Experimental; Studies

Intellectual merit: Immiscibility (boiling) in fluids approximated by the H2O-CO2-NaCl-KCl- CaCl2 system is common in many crustal environments, including epithermal precious metals deposits, porphyry copper-gold-molybdenum deposits, metamorphic lode gold deposits and other crustal igneous and metamorphic environments. Fluid immiscibility is an effective mechanism for partitioning and concentrating certain elements into one or the other of the two coexisting phases and thus plays an important role in crustal geochemical processes. Fluid inclusions provide the best evidence for the occurrence of fluid immiscibility in these environments, but our ability to interpret microthermometric and microanalytical data from natural inclusions is limited by the lack of experimental PTX data on compositions of coexisting fluids at crustal pressure-temperature (P-T) conditions. Experiments will be conducted using the synthetic fluid inclusion technique to determine compositions of coexisting fluids in the H2O-CO2-NaCl, H2O-NaCl-KCl and H2O-NaCl-CaCl2 ternary subsystems. The P-T limits of immiscibility will be defined based on observations of synthetic fluid inclusions trapped at known conditions. Fluid inclusions trapped in the one-phase fluid field all show identical room temperature phase relations and microthermometric behavior. Those trapped in the two-phase field show a bimodal distribution of phase behavior, indicative of the liquid and vapor phases that were present at elevated temperature and pressure. Compositions of the coexisting liquid and vapor phases will be determined from microthermometric analyses, interpreted using previously determined data for the appropriate fluid system, and supplemented by Raman spectroscopy to identify daughter minerals and to determine the H2O/CO2 ratio of CO2-bearing inclusions. The proposed research represents a continuation of ongoing experimental efforts designed to provide fundamental PVTX data on geologically-relevant fluids so that we may better understand the critical role that fluids play in the geochemical and rheological evolution of the crust and upper mantle. Broader impact: Funding provided by this grant will provide training for graduate students and help prepare them for successful careers in the earth sciences. This project will also support one or more undergraduate students each year to provide a meaningful research experience. The broader impacts also include lectures and workshops on Fluids in the Earth that the PI offers to students and professionals worldwide, as well as teaching introductory earth sciences courses to non-science majors at Virginia Tech. These activities reflect the broader impacts of the PI's research and the important role that quality undergraduate education plays in developing a scientifically literate society.

智力优点：H2O-CO2-NaCl-KCl-CaCl 2体系流体的不稳定性（沸腾）在许多地壳环境中很常见，包括低温热液贵金属矿床、斑岩型铜-金-钼矿床、变质矿脉型金矿床以及其他地壳火成岩和变质环境。流体不渗透性是将某些元素分配和富集到两种共存相中的一种或另一种的有效机制，因此在地壳地球化学过程中起着重要作用。流体包裹体提供了最好的证据，在这些环境中的流体不渗透性的发生，但我们的能力，解释microthermometric和microanalytical数据从天然包裹体是有限的，缺乏实验PTX数据的组成共存的流体在地壳压力-温度（P-T）条件。实验将采用合成流体包裹体技术来确定H2O-CO2-NaCl、H2O-NaCl-KCl和H2O-NaCl-CaCl 2三元子系统中共存流体的成分。不可渗透性的P-T极限将根据在已知条件下捕获的合成流体包裹体的观察结果来定义。单相流体场中捕获的流体包裹体具有相同的室温相关系和显微测温行为。那些被困在两相场显示双峰分布的相行为，指示的液相和气相，在升高的温度和压力。共存的液相和气相的成分将通过显微测温分析确定，使用先前确定的适当流体系统的数据进行解释，并通过拉曼光谱进行补充，以识别子矿物并确定含CO2包裹体的H2O/CO2比。拟议的研究代表了正在进行的实验工作的延续，旨在提供地质相关流体的基本PVTX数据，以便我们可以更好地了解流体在地壳和上地幔的地球化学和流变演化中发挥的关键作用。更广泛的影响：这笔赠款提供的资金将为研究生提供培训，并帮助他们为地球科学的成功职业做好准备。该项目每年还将支持一名或多名本科生提供有意义的研究经验。更广泛的影响还包括PI向世界各地的学生和专业人士提供的地球流体讲座和研讨会，以及向弗吉尼亚理工大学的非科学专业教授地球科学入门课程。这些活动反映了PI研究的更广泛影响以及优质本科教育在发展科学素养社会中发挥的重要作用。