SHI Xian-wen1, JIA Fu-ju1*, KE Long-yue2, ZOU Chao1
(1. Faculty of Land Resources Engineering Kunming University of Science and Technology, Kunming 650093, China;
2. NON-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou Second Team, Liupanshui 553004, China)
Abstract:The Huize super-large lead-zinc deposit, located on the southwestern margin of Yangtze plate, is a typical representative of a series of carbonate-type lead-zinc deposits in the Upper Yangtze lead-zinc metallogenic province. This paper takes the carbonate minerals and ore-bearing carbonate rocks developed in the Huize lead-zinc deposit in Yunnan as the research area, and systematically studies the C-O isotope composition characteristics. The average value of δ13C and δ18O of stone carbonate minerals is -2.82‰ and 17.70‰, respectively. The average value of δ13C and δ18O of the surrounding rock near the mine is -2.86‰ and 21.26‰, respectively. The average value of δ13C and δ18O of distant ore surrounding rocks is 0.41‰ and 24.24‰, respectively. The C-O isotopic compositions of the surrounding rock of the near mine is between the gangue calcite and the surrounding rock of the far mine, indicating that existence of exchange of C-O isotopes between the ore-reforming fluid and the surrounding rock. By comparison, it is inferred that the depletion of altered formation 13C is mainly result of the metasomatism of deep source fluids. The fluid metasomatizes the Carboniferous strata in the mining area from bottom to top, resulting in a decrease in the regularity of the mean value of δ13C from bottom to top. The altered strata 18O loss is mainly caused by karstification, and the average value of δ18O of the Lower Carboniferous Baizuo Strata is lower than that of the upper and lower adjacent layers, indicating that the strata has good water permeability, which is conducive to the mixing of ore-bearing fluids and karst groundwater, thereby causing ore-forming precipitation and ore bodies in place.
Keywords: Huize lead-zinc deposit; carbonate rock; C-O isotopes; source and evolution of ore-forming fluids
ACTA MINERALOGICA SINICA Vol.41, No.6, 2021, page 657-667
