| 河北省东坪金矿钾质蚀变岩中的两期锆石年代学研究及意义 |
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| 关键词:intense k-feldspar-altered rock zircon U-Pb dating magamatic zircon hydrothermal zircon Dongping gold deposit Hebei Province |
| 基金项目:国家自然科学基金重点项目(编号: 40234048)；全国重要矿产成矿地质背景研究(编号: 1212010633902)；中国地质大学地质过程与矿产资源国家重点实验室项目(编号: GPMR0735) |
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| Two Stage Zircon U-Pb Ages of the Potash Altered Rock in the Dongping Gold Deposit, Hebei Province, and Their Geological Implications |
| Located in Chongli County of Hebei Province, the Dongping gold deposit is hosted by the Shuiquangou alkaline complex. There are two types of gold ores in this ore deposit, namely the low-sulfide quartz veins and the intense k-feldspar alteration type. In this paper, the authors made a mineralogical and U-Pb geochronologic study of the zircons from the intense k-feldspar alteration of No.70 vein. Two types of zircons were recognized, i.e., magmatic and hydrothermal ones. The magmatic zircons are characterized by euhedral-subhedral crystals, dark gray color on the backscattered electron (BSE) image, and clear magmatic oscillatory zoning on cathodeluminescence (CL) image. The U-Pb analytical data of the magmatic zircons indicate a weighted mean 206Pb/238U age of 382.8±3.3 Ma. The hydrothermal zircons are mainly of irregular form filled with magmatic zircons. The hydrothermal zircons show light grayish white color on the BSE image and dark black color (non-luminescent) on the CL image. Compared with the magmatic zircons, the hydrothermal zircons have much higher Th, U content and Th/U ratios. The LA-ICP-MS zircon U-Pb age is 140.3±1.4 Ma. It is suggested that the Dongping gold deposit formed in the early Cretaceous. The discovery of the 140 Ma ore-forming age provides new evidence for the metallogenic epoch of the Dongping gold deposit. |
| LI Chang-min,DENG Jin-fu,SU Shang-guo,LI Hui-min,LIU Xin-miao.2010.Two Stage Zircon U-Pb Ages of the Potash Altered Rock in the Dongping Gold Deposit, Hebei Province, and Their Geological Implications[J].Acta Geoscientica Sinica,31(6):843-852. |
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