(1. 中國科學(xué)院 廣州地球化學(xué)研究所，礦物學(xué)與成礦學(xué)重點(diǎn)實(shí)驗(yàn)室，廣州 510640； 2. 中國科學(xué)院大學(xué)，北京 100049)
摘 要: 江西新余鐵礦位于欽杭成礦帶南側(cè)，為探討其變形變質(zhì)時代，針對礦區(qū)花崗巖體和賦礦圍巖開展了鋯石U-Pb定年工作。鋯石的透反射圖像、CL圖像和稀土元素特征及其(Sm/La)N-La和Ce/Ce*-(Sm/La)N判別圖表明山莊巖體的鋯石為巖漿鋯石，賦礦圍巖中的鋯石為變質(zhì)鋯石；鋯石U-Pb定年結(jié)果表明山莊巖體的侵入時代為420~419 Ma，礦區(qū)地層的變質(zhì)時代為214~213 Ma。它們和賦礦圍巖的巖相觀察及巖體與礦區(qū)地層的穿插關(guān)系共同表明新余鐵礦經(jīng)歷了加里東中晚期(＞420~419 Ma)的區(qū)域變質(zhì)作用和印支晚期有熱液參與的變質(zhì)作用。
關(guān)鍵字: 新余鐵礦；鋯石U-Pb定年；變質(zhì)作用；加里東期；印支期
（1. Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou Guangdong, 510640, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China）
Abstract: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)N of 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.
Key words: Xinyu iron ore area; zircon U-Pb dating; metamorphism; caledonian; indosinian
