Acomplishment Based Renewal (ABR): Trace Element Distribution Within, Between, and Among Metamorphic Minerals

用P.I.法研究了某些微量元素在变质岩矿物间的分布。和合作者在先前的NSF赠款是一个敏感的监测变质P-T条件和反应历史。最强的微量元素的签名被发现在岩石中的低至中等变质等级的石榴石结晶过程中的温度变化的估计只有几度可以辨别。在更高的变质等级下，石榴石中的微量元素浓度变得明显更低，需要更灵敏的分析仪器来进行浓度测量。该提案试图通过检查来自纽约阿迪朗达克山脉、智利南部达尔文山脉和瓦尔哈拉杂岩的高级岩石，将这项工作扩展到更极端的地壳条件。东不列颠哥伦比亚省使用微量元素敏感的分析技术（LA-ICP-MS和西姆斯）。一个主要目标将是将根据先前赠款开发的经验温度计扩展到这些更高的条件。第二个目标将是破译的共生和稳定范围的副矿物独居石，使有意义的解释U-Th-Pb年龄的这种矿物可以。本研究结果可广泛应用于世界范围内岩石学家和地球化学家对造山带副矿物的年代学研究。最终，这些结果应该提供显着更深入和更详细的了解过程中，造山作用。 PI将在该项目中支持一名女研究生。

SpearEAR-0337413The distribution of certain trace elements among minerals in metamorphic rocks has been shown by the P.I. and co-workers under prior NSF grants to be a sensitive monitor of metamorphic P-T conditions and reaction history. The strongest trace element signature was found in rocks of low to medium metamorphic grade where estimates of temperature changes during crystallization of garnet of only a few degrees could be discerned. At higher metamorphic grades, trace element concentrations become significantly lower in garnet, requiring more sensitive analytical instruments to make the concentration measurements.This proposal seeks to extend this work to more extreme crustal conditions by examining high-grade rocks from the Adirondack Mountains, New York, the Cordillera Darwin, southern Chile, and the Valhalla Complex, eastern British Columbia using trace-element sensitive analytical techniques (LA-ICP-MS and SIMS). A major goal will be to extend the empirical thermometers developed under the prior grant to these higher conditions. A second goal will be to decipher the paragenesis and stability range of the accessory mineral monazite, so that meaningful interpretations of U-Th-Pb ages of this mineral can be made. The results of this study will be widely applicable to research by petrologists and geochemists that use geochronology on accessory minerals in orogenic terranes worldwide. Ultimately, these results should provide significantly deeper and more detailed insights into the processes that operate during orogenesis. The PI will support a female graduate student in this project.