In-situ trace element analyses and Pb-Pb dating of zircons in granulite from Huangtuling, Dabieshan by LAM-ICP-MS

作     者：吴元保 陈道公 夏群科 涂湘林 程昊 杨晓志 

作者机构：Department of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2003年第46卷第11期

页      面：1161-1170页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：the National Natural Science Foundation of China(Grant Nos.40033010 , 40273028) the National Key Basic Research Program(Grant No.G1999075503) partly supported by the Guangzhou Association of Scientific Instruments Cooperation 

主　　题：granulite, zircon, trace element, Pb-Pb age, LAM-ICP-MS. 

摘      要：It is revealed by CL images that there are multi-stage growth internal structures of zircons in the Huangtuling granulite, including the inherited zircons, protolith zircons, sector and planar zone zircons and retrograde zircons. In-situ trace element compositions and Pb-Pb ages have been analyzed by LAM-ICP-MS. The sector and the planar zone domains show typical trace element characteristics of granulite zircon (low Th, U, Th/U, total REEs, clear negative Eu anomalies, relatively depleted HREE and small differential degree between MREE and HREE, etc.), indicating that they formed during granulite-facies metamorphism. The protolith zircons have trace element characteristics of crustal zircon (high Th, U, Th/U, total REEs and enriched HREEs, etc.). 12 analyzed spots on granulite-facies domains give a weighted mean 207Pb/206Pb age of (2154±26) Ma (MSWD = 3.8), which is the best estimated age of granulite-facies metamorphism of this sample. The weighted mean 207Pb/206Pb age of 5 analyzed spots on protolith zircon domains is (2714 ± 22) Ma (MSWD = 1.4), which represents the protolith forming time. The discovery of ca. 3.4 Ga inherited zircon indicates that there are Palaeoarchean continental materials in this area. The interpretation of formation conditions and the ages of zircons can be constrained by simultaneous in-situ analysis of trace elements and ages.