本项目拟以北秦岭官坡和松树沟地区不同变质程度榴辉岩及其围岩片麻岩中的副矿物（榍石、金红石和独居石）为重点研究对象，通过细致的显微结构和包裹体矿物组合观察，进一步识别榴辉岩及片麻岩中榍石、金红石和独居石的多期次生长；利用原位微区主微量元素及同位素年代学分析，结合矿物微量元素温度计的应用，准确限定榴辉岩及片麻岩中不同变质期次榍石、金红石和独居石的形成温压条件和形成时代，结合研究区内现有高压-超高压岩石变质作用和锆石年代学的研究结果，构建北秦岭高压-超高压岩石完整连续的P-T-t演化轨迹；进一步查明榴辉岩及片麻岩中不同变质期次榍石、金红石和独居石的元素分布特征和变化规律，探讨北秦岭大陆俯冲-折返过程中高压-超高压岩石的熔/流体活动和元素迁移。

This project mainly focus on accessory minerals (titanite, rutile and monazite) in eclogites and its host gneisses from the Guanpo and Songshugou areas, North Qinling ultrahigh pressure metamorphic belt. We will carry on detailed observations of microstructure and mineral inclusions, in order to distinguish the polygenetic accessory mineral growth. Detailed in-situ analyses of elements and isotopes in these accessory minerals (titanite, rutile and monazite), and combined with the application of trace elements thermometries, will be determined their pressure and temperature conditions and formation time. In combination with these results and the previous studies on metamorphism and zircon chronology, the continuous and entire P-T-t paths for the North Qinling HP-UHP rocks will be obtained. Furthermore, we will ascertain the distribution characteristics of trace elements in these accessory minerals (titanite, rutile and monazite) during different metamorphic stages, which will provide geochemical insights into fluid/melt action and element mobility for HP-UHP rocks during the process of continental deep subduction and exhumation.