JIN Ting-fu1, LUO Wei2*, LI You-guo3, LI Peng-wei4, SUN Teng-jiao3, LAN Ye-fang1
(1. Guizhou University of Engineering Science, Bijie 551700, Chian;
2. Zunyi Normal University, Zunyi 563006, China;
3. Chengdu University of Technology, Chengdu 610059, China;
4. Petroleum Exploration and Production Research Institute，SINOPEC，Beijing 100083，China)
Abstract: The southwestern margin of Yangtze block, known as the Kangdian copper metallogenic belt, is an important production area of iron-copper polymetallic resources in China, as there are many small－large iron-copper polymetallic deposits. The Dahongshan deposit which is studied in this study is one of the biggest iron-copper polymetallic deposits in the southwestern Yangtze block. The dating results of calcites in Fe-Cu-mineralized calcite veins indicate that the Sm-Nd isochron age of 818±3 Ma represents the mineralization age of magnetite and chalcopyrite in calcite veins. Combined with researches on the relationship and background of diagenesis and metallogenesis of the southwestern margin of Yangtze block, it is suggested that the mineralization event could be related to continental rift environment in the breakup period of Rodinia supercontinent. Based on compositional characteristics of the Sm-Nd isotope system of calcites including the (143Nd/144Nd)i value of 0.5112649 and εNd(t=818 Ma) values ranging from -6.3 to -6.2, it is indicated that the Nd in calcite could be from a mixed source of crust and mantle, with majority of the mantle source.
Keywords: Sm-Nd isochron age; calcite; Dahongshan iron-copper polymetallic deposit; southwestern margin of the Yantze block
ACTA MINERALOGICA SINICA Vol. 41, No.3, 2021, page 343-354