U-Pb Dating and Trace Elements Composition of Hydrothermal Zircons from Jianfengling Granite, Hainan. Restriction on the Age of Hydrothermal Event and Mineralization of Baolun Gold Deposit
ZHANG Xiao-wen
XIANG Hua
ZHONG Zeng-qiu
ZHOU Han-wen
ZHANG Li
YANG Nian
WANG Jing
Abstract：Detailed studies on zircons from the Jianfengling granite in the Baolun gold deposit indicate that the zircons can be divided into magmatic and hydrothermal zircons. The magmatic zircons are colorless, transparent, prismatic, euhedral crystal with few inclusions, and have moderate U, Th contents (mostly less than 1 000 μg/g). LA-ICP-MS U-Pb analyses of these zircons gave a weighted mean ~(206)Pb/~(238)U concordia age of 240±2. 1 Ma, which is interpreted as the age of emplacement for the Jianfengling granite. Hydrothermal zircons are brown, translucence to opaque, and have extremely high U, Th and trace elements contents, the highest U, Th contents being 30 000 μg/g, 20 000 μg/g, respectively. Hydrothermal zircons have high common Pb contents (~(206) Pb_c = 0. 77%-11. 0%). LA-ICP-MS U-Pb analyses of these zircons gave the age from 106 to 120 Ma, with a weighted mean ~(206)Pb/~(238)U age of 112. 8±4. 3 Ma, which is interpreted as the age of hydrothermal event It is indicated that there is a strong hydrothermal process at ca. 112. 8 Ma, which might be related to Yanshanian magmatism in this area. Gold mineralization of Baolun gold deposit is most likely related with this hydrothermal event U-Pb dating on hydrothermal zircons could be used to constrain the timing of hydrothermal event and constrain the timing of gold mineralization related with hydrothermal event.
Keywords：Jianfengling granitehydrothermal zirconU-Pb datingBaolun gold depositgeochronology.
Publication Date：2009-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 921-930 )