Abstract

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Title:: Review on Jianglang Dome and Liwu-type Cu-rich Deposit in the Western Margin of Yangtze Block

Author(s):: DAI Yan-pei; ZHANG Hui-hua; ZHU Yu-di; SHEN Zhan-wu; LI Tong-zhu; MA Dong; 1. Chengdu Center, China Geological Survey, Chengdu 610081, Sichuan, China; 2. School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, Sichuan, China

Keywords:: metamorphic core complex; formation age of strata; metamorphosed basement; mineralization age; genesis of mineral deposit; Cu deposit; Jianglang dome; Yangtze Block

Abstract:: Jianglang dome is located in the western margin of Yangtze Block, and is famous for the occurrences of Liwu-type Cu-rich deposit. Jianglang metamorphic core complex, source bed, mineralization age and the relationship between structural deformation and mineralization were summarized. The results show that zircon U-Pb dating on para metamorphic rocks and metabasalts can determine the formation ages of Liwu Group, Jianglangyan Formation and Jiabayan Formation, through which the existence of Archean or Paleoproterozoic metamorphosed basements could be ascertained; ⁴⁰Ar/³⁹Ar dating on biotite in the bedding ductile shear zone (pre-doming) and sericite in the gravity gliding folds (the later stage of doming) can constrain the timing of doming; Liwu-type Cu-rich deposit is medium-high hydrothermal veined Cu deposit, with the geological features and ore-forming fluid signatures similar to those of orogenic deposits; the mineralization ages are reliable by means of Rb-Sr (chalcopyrite), Re-Os (chalcopyrite and pyrrhotite), U-Pb (hydrothermal zircons in ore-bearing quartz veins) and Sm-Nd (garnet in mineralization belts) isotopic dating. Therefore, the applications of advanced measuring techniques are helpful to settle the key geological problems of Jianglang dome and Liwu-type Cu-rich deposits. Moreover, the comparative studies on domes in the western margin of Yangtze Block are apparently beneficial to regional prospecting.