Trace Element Distribution Within, Between, and Among Metamorphic Minerals

这个建议是发展微量元素划分作为一种工具，以协助岩石学家破译一个地体的变质历史，并应用这种工具来进一步我们对地球历史的理解。对部分熔融（深熔）变质岩和高P/T变质岩进行详细研究，全面表征主、副相微量元素的分带和分划。将扩大和加强对独居石-xenotime温度计的经验校准，以包括HREE， Th和U对独居石YPO4含量的影响，以及为该温度计的应用开发的程序，以产生有意义的结果。另外两种温度计，YAG-xenotime和YAG-monazite，也将得到类似的改进，以便它们适用于广泛的条件。另外，基于高压下石榴石和副矿物之间钇分配的新的经验温度计将被探索，整个岩石反应和矿物组成变化的热力学模型将被开发，使副矿物共生建立在坚实的理论基础上。这些模型将用于预测辅助矿物在主要相反应中的作用，并用于解释在研究套件中观察到的天然共生。

SpearEAR-0106738 This proposal is to develop trace element partitioning as a tool to assist petrologists in the task of deciphering the metamorphic history of a terrane, and to apply this tool to further our understanding of Earth history. Detailed studies will be carried out on metapelites that have undergone partial melting (anatexis) and rocks that have undergone high P/T metamorphism in order to characterize fully the trace element zoning and partitioning in major and accessory phases. An empirical calibration of a monazite-xenotime thermometer will be augmented and enhanced to include the influence of HREE, Th and U on monazite YPO4 content, and procedures developed for the application of this thermometer to yield meaningful results. Two additional thermometers, YAG-xenotime and YAG-monazite, will be similarly enhanced so that they are applicable over a wide range of conditions. Additional new, empirical thermometers based on yttrium partitioning between garnet and accessory minerals at high pressures will be explored Thermodynamic models of whole rock reactions and mineral composition variation will be developed to place accessory mineral paragenesis on a firm theoretical footing. The models will be used to make predictions about the involvement of accessory minerals in major phase reactions, and in the interpretation of natural parageneses observed in the study suites.