LA‐ICP‐MS Zircon U‐Pb Geochronology of the Fine‐grained Granite and Molybdenite Re‐Os Dating in the Wurinitu Molybdenum Deposit, Inner Mongolia, China

• Published in: Acta Geologica Sinica - English Edition
• Main Authors: LIU, Cui, DENG, Jinfu, KONG, Weiqiong, XU, Liquan, ZHAO, Guochun, LUO, Zhaohua, LI, Ning
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2011
• Subjects: okhotsk sea
• Online Access: http://dx.doi.org/10.1111/j.1755-6724.2011.00540.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1755-6724.2011.00540.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1755-6724.2011.00540.x

Abstract: The Wurinitu molybdenum deposit, located in Honggor, Sonid Left Banner of Inner Mongolia, China, is recently discovered and is considered to be associated with a concealed fine‐grained granite impregnated with molybdenite. The wall rocks are composed of Variscan porphyritic‐like biotite granite and the Lower Ordovician Wubin'aobao Formation. LA‐ICP‐MS zircon U‐Pb dating of the fine‐grained granite reveals two stages of zircons, one were formed at 181.7±7. 4 Ma and the other at 133.6±3.3 Ma. The latter age is believed to be the formation age of the fine‐grained granite, while the former may reflect the age of inherited zircons, based on the morphological study of the zircon and regional geological setting. The Re‐Os model age of molybdenite is 142.2±2.5 Ma, which is older than the diagenetic age of the fine‐grained granite. Therefore the authors believe that the metallogenic age of the Wurinitu molybdenum deposit should be nearly 133.6±3.3 Ma or slightly later, i.e., Early Cretaceous. Combined with regional geological background research, it is speculated that the molybdenum deposits were formed at the late Yanshanian orogenic cycle in the Hingganling‐Mongolian orogenic belt, belonging to the relaxation epoch posterior to the compression and was associated with the closure of the Mongolia‐Okhotsk Sea.