Serpentinization Effects on Forearc Peridotite: Mineralogic, Textural, and Geophysical Study

蛇纹石化对弧前橄榄岩的影响：矿物学、结构和地球物理研究

• 批准号: 0752322
• 负责人: Patricia Fryer
• 金额: --
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752322&HistoricalAwards=false
• 关键词: Serpentinization; Effects; Forearc; Peridotite; Mineralogic

ABSTRACT 0752322 (Fryer)Intellectual Merit: This research addresses fundamental questions of the role of water in convergent plate margins requires by using geochemical indicators to determine the flux of fluids from a subducting plate and the stresses imposed by subduction affect the overriding plate's mantle. Samples mantle material erupted from serpentinite mud volcanoes on the Mariana forearc will be examined from sites 15 to 90 km from the trench and up to ~720 km along strike. Mineralogy and textures of the rocks will be examined quantitatively to determine the history and evolution of stress regimes in the forearc mantle. Middle-infrared (MIR) spectroscopy will be used to determine rough mineral percentages, with the data being verified by petrography. Micro-Raman mapping will be used to determine for detailed mineralogy. Electron backscatter diffraction will give orientation of olivine grains (microtextures reflect stress patterns in the forearc mantle). Selected samples will then be subjected to seismic velocity measurements to relate textural anisotropy and degree of serpentinization to seismic field measurements. This research provides the first integrated regional data set on the effects of serpentinization of natural samples and of evolution of strain in the forearc mantle. The data will allow better interpretation of geophysical field data and the controls on subduction-zone seismicity. The MIR data coupled with detailed petrographic and textural analysis will enable more accurate analysis of field samples and interpretation of remote sensing data. Broader Impacts: This research has broad implication to large subduction zone fault studies, such as those on the San Andreas and Calvert faults. It will train both graduate and undergraduate students in the US, Japan and Canada. The work enhances the infrastructure for research and education by involving multidisciplinary research at three institutions. It also supports two female PIs, both of whom are at an EPSCoR institution (University of Hawaii). Results will be presented on the internet and on CD for informal and formal education for K-12 students, undergraduates, and the general public. The project will enhance the NSF-funded MARGINS-supported efforts in the Mariana region and ODP/IODP drilling in the Mariana forearc.

摘要0752322（弗赖尔）学术成就：这项研究解决了水在会聚板块边缘的作用的基本问题，需要使用地球化学指标来确定来自俯冲板块的流体通量，以及俯冲作用所施加的应力影响覆盖板块的地幔。 从马里亚纳前弧蛇纹岩泥火山喷发的地幔物质样本将在距离海沟15至90公里的地点进行检查，并沿走向沿着延伸至~720公里。岩石的矿物学和结构将被定量研究，以确定弧前地幔应力状态的历史和演化。 中红外光谱将用于确定粗矿物百分比，数据将通过岩相学进行验证。显微拉曼成像将用于确定详细的矿物学。电子背散射衍射将给出橄榄石颗粒的取向（显微结构反映了弧前地幔的应力模式）。然后对选定的样品进行地震速度测量，将结构各向异性和蛇纹化程度与地震现场测量结果联系起来。 这项研究提供了第一个综合的区域数据集的影响，蛇纹化的天然样品和演化的应变在弧前地幔。 这些数据将有助于更好地解释地球物理场数据和控制俯冲带地震活动。 和平号红外数据加上详细的岩相和结构分析，将能够更准确地分析实地样品和解释遥感数据。更广泛的影响：这项研究对大型俯冲带断层的研究有广泛的意义，比如圣安德烈亚斯断层和卡尔弗特断层。 它将在美国、日本和加拿大培养研究生和本科生。这项工作通过涉及三个机构的多学科研究，加强了研究和教育的基础设施。 它还支持两名女性PI，她们都在EPSCoR机构（夏威夷）。 结果将在互联网上和CD上呈现，用于K-12学生，本科生和公众的非正式和正式教育。 该项目将加强由NSF资助、MARGINS支持的马里亚纳地区的工作以及马里亚纳前弧的ODP/IODP钻探。