Tectonic and Metamorphic Implications for High Cl-Contents in Serpentinites

SharpOcean蛇纹岩含有高浓度的水溶性氯化物，应该是一个重要的载体，负责从外逸层中去除Cl，作为俯冲带中高盐度流体的来源。 提出了四个目标：1）通过表征ODP岩心和仰拱当量，更好地限制蛇纹岩的Cl含量及其丰度，2）使用电子微束和TEM技术表征Cl -在蛇纹岩中的矿物学位置，3）检查弱变质和更高变质的蛇纹岩体和相关围岩，以寻找高盐度流体及其变质/交代作用的证据;测定蛇纹岩和相关岩性的氯同位素比值，以确定Cl的来源。 这项工作将包括阴离子浓度的直接测量，流体包裹体的盐度测定，H，O和Cl同位素比值，以及评价脉和剪切带中的交代作用，作为高盐度流体通过期间元素迁移的间接证据。 更广泛的影响-本提案中概述的综合办法将有助于更好地了解高盐度流体在与深俯冲有关的变质作用中的重要性以及这种流体的来源。 这项工作将由三名PI，一名博士，学生和本科生（荣誉论文）和高中生（NASA SHARP暑期实习）。该项目将包括各级的大量学生，包括少数民族高中生，他们将受益于真实的科学探究的实践经验。

EAR-0309794SharpOcean serpentinites contain a high concentration of water-soluble chlorides, and should be an important carrier responsible for removal of Cl from the exosphere as a source for high-salinity fluids in subduction zones. Four goals are proposed: 1) to better constrain the Cl content of serpentinites and their abundance by characterizing ODP cores and obducted equivalents, 2) to characterize the mineralogical siting of Cl - in serpentine using electron microbeam and TEM techniques, 3) to examine weakly and more highly-metamorphosed serpentinite bodies and associated wallrocks for evidence of high salinity fluids and their metamorphic/metasomatic effects and 4) measure chlorine isotope ratios of serpentinite and related lithologies in order to identify the origin of Cl. This work will include direct measurements of anion concentrations, salinity determinations of fluid inclusions, H, O and Cl isotope ratios, and evaluation of metasomatism in veins and shear zones as indirect evidence for element migration during passage of high-salinity fluids. Broader impacts - The integrated approach outlined in this proposal will lead to a better understanding of the importance of high-salinity fluids in deep subduction-related metamorphism, and the source of such fluids. The work will be carried out by the three PIs, a Ph.D. student and undergraduate (honor's thesis) and high school students (NASA SHARP summer internship). The project will include a large number of students at all levels, including minority high school students who will benefit from hands-on experience of a real scientific inquiry.