In order to discuss the deformable and metamorphic age of Xinyu iron ore which is on the southern side of Qinhang metallogenic belt and located in Jiangxi Province, zircon U-Pb dating for the granite and host rock were carried out. Zircons from Shanzhuang granite are interpreted as magmatic zircon and Zircons from host rock as metamorphic zircon by transmission and flection images, CL images, rare earth element and discrimination diagrams of (Sm/La)N?La and Ce/Ce*?(Sm/La)Nof zircon. Zircon U-Pb dating indicates that the intrusion age of Shanzhuang granite is 420?419 Ma and the metamorphic age of mining area is 214?213 Ma; they and lithofacies observation and the interpenetration relation between granite and stratum show that Xinyu iron ore area experiences middle-late regional metamorphism of Caledonian(＞420?419 Ma) and late Indosinian metamorphism associated with hydrothermal activity.%江西新余铁矿位于钦杭成矿带南侧,为探讨其变形变质时代,针对矿区花岗岩体和赋矿围岩开展了锆石U-Pb定年工作.锆石的透反射图像、CL图像和稀土元素特征及其(Sm/La)N?La和Ce/Ce*?(Sm/La)N判别图表明山庄岩体的锆石为岩浆锆石,赋矿围岩中的锆石为变质锆石;锆石 U-Pb 定年结果表明山庄岩体的侵入时代为420~419 Ma,矿区地层的变质时代为214~213 Ma.它们和赋矿围岩的岩相观察及岩体与矿区地层的穿插关系共同表明新余铁矿经历了加里东中晚期(＞420~419 Ma)的区域变质作用和印支晚期有热液参与的变质作用.
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