Earth Science Frontiers ›› 2018, Vol. 25 ›› Issue (5): 119-134.DOI: 10.13745/j.esf.sf.2018.4.18

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Zircon U-Pb age, geochemistry and Hf isotopes of the causative porphyry from the Bilihe porphyry gold deposit, Inner Mongolia.

ZHU Xuefeng,CHEN Yanjing,WANG Pin,ZHANG Cheng,CAI Yunlong,DENG Ke,XU Qiangwei,LI Kaiyue   

  1. 1. MOE Key Laboratory of Orogenic Belts and Crustal Evolution, Peking University, Beijing 100871, China
    2. School of Mining and Coal, Inner Mongolia University of Science and Technology, Baotou 014010, China
    3. Key Laboratory of Ocean and Marginal Sea Geology, Chinese Academy of Sciences; South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
    4. Sonid Jinxi Gold Mining Co. Ltd., Sonid Youqi 011200, China
  • Received:2018-02-08 Revised:2018-06-28 Online:2018-09-15 Published:2018-09-15

Abstract: The Bilihe gold deposit, located in the Bainaimiao arc along the northern margin of the North China Craton (NCC), is considered a porphyry mineralization system. This study is focused on the LA-ICP-MS U-Pb geochronology and Lu-Hf isotopic composition of zircons from the causative granodiorite. The results show that geochemical features, such as peraluminous high-K calc-alkaline characteristics, SiO2 content (61.3%64.4%), ratios of K2O/Na2O (0.520.87) and A/CNK (0.820.95), enrichment of LILEs (eg. Rb, U, Th) and LREEs, depletion of HFSEs (eg. Nb, Ta, Ti) and HREEs, and negative Eu anomalies (δEu=0.501.03), indicate the Bilihe granodiorite is similar to typical arc-related granitoids. Also, two granodiorite samples (zk086-53 and zkI005-105) had similar zircon ages and Lu-Hf isotopic characteristics, with weighted mean 206Pb/238U ages of 268.1±1.8 Ma (MSWD=1.17, 1σ) and 267.7±4.1 Ma (MSWD=1.06, 1σ), respectively,  εHf(t) values of 3.28.7 and -0.68.3, respectively, and TDM2 ages of 1085737 Ma and 1330762 Ma, respectively, suggesting that the Bilihe causative granodiorite likely formed during the EarlyMiddle Permian, from the underplating magma of partially molten juvenile crust mixed with partially molten ancient basement rocks in a continental arc setting.
Key words: Central Asian orogenic belt; Solonker zone; Bilihe gold deposit; zircon U-Pb ages; Lu-Hf isotopes

Key words: Central Asian orogenic belt, Solonker zone, Bilihe gold deposit, zircon U-Pb ages, Lu-Hf isotopes

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