Earth Science Frontiers ›› 2021, Vol. 28 ›› Issue (4): 267-282.DOI: 10.13745/j.esf.sf.2020.12.6

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Characterization of the Xiaokelehe granite porphyry in the Northern Great Xing’an Range

CHEN Zhigang1(), LI Yongsheng2,*(), YU Xiaofei2, WANG Ying3, ZHEN Shimin2, GONG Fanying2   

  1. 1. Agency Services Bureau, Ministry of Natural Resources, Beijing 100812, China
    2. Development and Research Center, China Geological Survey, Beijing 100083, China
    3. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
  • Received:2020-05-12 Revised:2020-09-25 Online:2021-07-25 Published:2021-07-25
  • Contact: LI Yongsheng


The Xiaokelehe Mo(Cu) deposit is a newly discovered porphyry deposit in the Northern Great Xing’an Range and related to the granodiorite porphyry. The granite porphyry veins, intruding into the granodiorite porphyry, are superimposed with new alteration and mineralization. Potash feldspathization, silicification and sericitization are developed in the wall rock contacting the granite porphyry. In this alteration zone, it developed veinlet-disseminated pyrite, chalcopyrite and molybdenite—specially abundant, indicating an medium to high temperature of alteration and mineralization. In this paper, LA-ICP-MS zircon U-Pb geochronology, whole-rock geochemistry and Hf isotope were used to constraint the magmatic source and tectonic setting. The zircon U-Pb age obtained for granite porphyry was 131.42±0.39 Ma, corresponding to the Early Cretaceous. The Xiaokelehe granite porphyry is mainly composed of orthoclase, albite, microcline and quartz. No mafic alkaline and peraluminous minerals were observed. The granite porphyry belongs to high-K calc-alkaline series, characterized by high contents of SiO2(76.24-77.55%) and (K2O+Na2O) (8.12-8.44%), and low contents of MgO (0.09-0.16%) and CaO (0.30-0.65%). The A/CNK ratio ranged between 0.94-1.04. The rocks also showed pronounced depletions of Nb, P and Ti, and enrichments of Rb, Th and U. The (Zr+Nb+Ce+Y) content and 10000 Ga/Al ratio were below the lower limits of the A-type granite. Integrated mineralogical, geochemical data suggest that the granite porphyry is a highly differentiated I-type granite. Hafnium isotopic analysis of zircons from the granite porphyry yielded εHf(t) value of -0.2 to 4.0 and two-stage model age (TDM2) of 931 to 1199 Ma, indicating the magmas were derived from partial melting of juvenile crustal material, with addition of ancient crustal materials. It is believed that the porphyry deposit was formed under the extensional environment related to the paleo-Pacific and Mongol-Okhotsk Plates. The Late Jurassic-Early Cretaceous was an important period of Mo(Cu) mineralization in the middle and northern Great Xing’an Range. The shallow high-K calc-alkaline granitic intrusion is important for exploring porphyry Mo(Cu) deposit.

Key words: northern segment of the Great Xing’an Range, Xiaokelehe, granite porphyry, geochemistry, zircon U-Pb dating, Hf isotope

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