Distribution,origin and its dynamic background of porphyry copper deposits in Southwest China
Based on the compilation of the 1:1000000 mineral map of the Southwest region and combined with previous research results,the authors propose that the porphyry copper deposits in the Southwest region can be divided into five porphyry copper belts:(1) Gangdise porphyry copper belt;(2) Duobuza-Polong porphyry copper belt;(3) Yulong porphyry copper belt;(4) Yidun-Zhongdian porphyry copper belt;(5) Porphyry copper belt of western margin of Yangtze Craton. The authors discuss the regional geological background and ore deposit distribu-tion,geological and geochemical characteristics of ore-bearing porphyries,and the source of ore-forming materials for these porphyry copper belts. Finally,using the theory of ancient continental margin metallogeny,it is suggested that the ore-bearing porphyries in the porphyry copper belts exhibit "continental crustal" characteristics in chemi-cal composition,while showing "island arc" characteristics in trace and rare earth elements,indicating that the formation of the porphyry copper belts in the Southwest region is controlled by both the source of ore-forming materi-als and the process of continent-continent collision,ultimately being controlled by the characteristics of the evolu-tion of the ancient continental margin structure,namely "overlapping". The authors summarize and discuss the genesis of the porphyry copper deposits in each belt,as well as their location and metallogenic dynamics background during the transition from sea to land.
万方数据
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