锆石U/Pb年代学及其对大别碰撞造山作用过程的制约

This project carried on the following researches: insite micro-scale U-Pb geochronology, internal structure(CL, BSE, Raman), mineral inclusion, and concentration and distribution of REE and trace elements for zircon from different metamorphic rocks of Dabie orogen.It is indicated that metamorphic zircon formed mainly by re-crystallization of protolith zircon, and new growth as well. The characteristics of metamorphic zircon is quite different from magmatic zircon. The formation of metamorphic zircon is not necessary to correlate with peak metamorphic , but also to prograde and/or retrograde metamorphism. The protoliths of Dabie metamorphic rocks are multi-sources and have three groups in age: 700-800Ma, 1.9Ga and 2.5 Ga. It is also showed that in order to get definite interpretation of zircon age meaning, we have to combine all the data of its insite U-Pb age, chemical compositions and internal stractures. Detailed work can forward to correlate formation of metamorphic zircon with a particular P and T condition of metamorphic event.

通过对大别碰撞造山带中以榴辉岩为代表的超高压（UHP）变质岩、围岩片麻岩和北大别TTG组合岩石中的各类锆石进行详细的成因矿物学、U/Pb年代学、锆石微区SIMS定年和地球化学研究，了解各类岩石及其源岩的化学特征和形成时间，探讨UHP作用中锆石的行为，确认岩捅渲曙媚炅涞囊庖澹佣猆HP岩石的时空分布造山带的框架构造提供年代学制约。