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

摘要0752322(弗莱尔)智力价值：这项研究解决了水在会聚板块边缘所需的基本问题，通过使用地球化学指示器来确定俯冲板块的流体流量，以及俯冲施加的压力影响到俯冲板块的地幔。马里亚纳岛前弧上蛇纹岩泥火山喷发的地幔物质样本将在距离海沟15至90公里和沿走向长达720公里的地点进行检查。将对岩石的矿物学和结构进行定量研究，以确定弧前地幔应力状态的历史和演化。中红外(MIR)光谱将用于确定粗矿物百分比，数据由岩石学验证。将使用显微拉曼作图来确定详细的矿物学。电子背散射衍射将给出橄榄石颗粒的取向(微观结构反映了弧前地幔中的应力模式)。然后对选定的样品进行地震速度测量，以将结构各向异性和蛇纹化程度与地震现场测量联系起来。这项研究首次提供了关于自然样品的蛇纹岩作用和弧前地幔应变演化的影响的综合区域数据集。这些数据将允许更好地解释地球物理场数据和对俯冲带地震活动的控制。和平研究所的数据与详细的岩相学和纹理分析相结合，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具有广泛的意义，例如圣安德烈亚斯和卡尔弗特断层上的研究。它将在美国、日本和加拿大培养研究生和本科生。这项工作加强了研究和教育的基础设施，涉及三个机构的多学科研究。它还支持两名女性PI，她们都在EPSCoR机构(夏威夷大学)工作。结果将在互联网和光盘上公布，供K-12学生、本科生和普通公众进行非正规和正规教育。该项目将加强国家科学基金会资助的马里亚纳地区利润率支持的努力以及马里亚纳岛前弧区的ODP/IODP钻探。

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.