Thermal-tectonic history of the Baogutu porphyry Cu deposit,West Junggar as constrained from zircon U-Pb,biotite Ar/Ar and zircon/apatite(U-Th)/He dating
作者单位：Key Laboratory of Mineral ResourcesInstitute of Geology and GeophysicsChinese Academy of Sciences Graduate University of Chinese Academy of Sciences CSIRO Earth Science and Resource Engineering John de Laeter Center for Isotope ResearchDept. Applied Geology/Applied PhysicsCurtin University State Key Laboratory of Geological Processes and Mineral ResourcesFaculty of Earth SciencesChina University of Geosciences
会议名称：《中国科学院地质与地球物理研究所2014年度（第14届）学术年会》
会议日期：2015年
学科分类：070902[理学-地球化学] 081803[工学-地质工程] 0709[理学-地质学] 07[理学] 08[工学] 0818[工学-地质资源与地质工程]
关 键 词：Western Junggar Baogutu porphyry copper deposit Zircon U-Pb dating Ar/Ar dating Zircon(U-Th)/He dating Apatite(U-Th)/He dating Thermal-tectonic history
摘 要：Understanding postmineralization tectonic movements in porphyry deposits,is critical to interpreting the complete thermal-tectonic *** study reports new zircon U-Pb ages,hydrothermal biotiteAr/Ar age,and zircon and apatite(U-Th)/He ages from the Baogutu porphyry copper deposit,which,in conjunction with pre-existing geochronology and thermochronology and inverse modeling simulations,constrain the thermal-tectonic history of the *** LA-ICP-MS U-Pb concordia ages indicate a Late Carboniferous age of 320.1 ± 2.2 Ma for the diorite complex and 309.8 ± 2.2 Ma for the mineralized granodiorite *** biotite selected from a quartz-biotite-chalcopyrite vein yields a plateau age of 311.0 ± 1.8 Ma which agrees with the age of the granodiorite porphyry and a previously reported molybdenite Re-Os age,and suggests that hydrothermal fluid circulated about310 *** and granodiorite porphyry yield weighted mean zircon(U-Th)/He ages of200.6±5.7Ma and 241.1 ±8.1 Ma,respectively,with ages ranging from 221.0 Ma to 174.3 Ma and225.9 to 261.6 *** mean diorite and granodiorite porphyry apatite(U-Th)/He ages of87.4 ± 2.3 Ma and 120.0 ± 4.2 Ma were obtained with ages ranging from 68.9 Ma to 100.8 Ma,and from91.0 Ma to 152.0 Ma,*** wide range of zircon(U-Th)/He ages may be due to the combined effects of U and Th zonation and radiation damage,and radiation damage effect may also account for the wide range of apatite(U-Th)/He *** combined effects of depth and cooling due to meteoric water circulation contribute to an older(U-Th)/He age for the granodiorite porphyry,relative to the diorite.A five-episode cooling rate history for the diorite can be deduced by inverse model simulation:fast cooling—moderate fast cooling—relatively slow cooling—fast cooling again—very slow *** thermal and tectonic history of the wall rock indicates that it suffered significant far-field effects from the Qiangtang-Eurasia and Lhasa-Qiangta