Ore-Forming Fluid Geochemical Characteristics and Genesis of Pb-Zn Deposit in Hongling,Inner Mongolia
Li Jianfeng
Wang Keyong
Lu Jisheng
Zhang Xuebing
Quan Hongyan
Wang Chengyang
Wei Liangmin
Abstract：Hongling lead-zinc deposit is one of the representative large deposits in southeastern Inner Mongolia.Presently,there’s very little research on geochemical characteristics and evolution of ore-form fluids,and ore genesis.The fluid inclusions are systemly re-searched in this paper,The results show that there are three types of primary fluid inclusions in garnet of garnet-skarn stage (Ⅰ)inclu-ding halite-bearing three-phase,aqueous two-phase as well as vapor-rich two-phase;there are two types of primary fluid inclusions in quartz of stage (Ⅱ)including aqueous two-phase as well as vapor-rich two-phase.It is found in our microthermometric study that the ore-forming fluid is of high temperature,high salinity and immiscible NaCl-H2 O type solutions and the boiling process plays important role in the precipitation of Pb,Zn,and Cu.Quartz of mineralization stage Ⅲ to Ⅳ of quartz-sulfide epochs contains only aqueous two-phase of fluid inclusions.The homogenization temperature of this type of fluid inclusions is obviously lower than that of skarn epoch, while the salinity does not obviously change.The homogenization temperatures of fluid inclusions show a rising trend with salinities dis-playing a dropping trend of stage Ⅳ,and it may be caused by adding of high temperature,low salinity type fluid.The dropping of homogenization temperatures and salinities of ore-forming fluids from mineralization stages Ⅴ to Ⅵ suggests that meteoric water contin-uously joining into the ore-forming fluid.Overall,the ore-forming fluids of quartz-sulfide epoch is of medium-low temperature and low salinity NaCl-H2 O type solutions.C,H,O isotope study of fluid inclusions shows that the ore-forming fluids of skarn epoch mainly came from magmatic water and that of quartz-sulfide epoch came from mixed magmatic water and meteoric water,whereas at the latest stage of mineralization,the ore-forming fluids mainly came from meteoric water.The study of S,Pb isotopes implies that the ore-forming materials posed a deep source feature.
Keywords：Hongling Pb-Zn depositore-forming fluidgeochemistryore depositssoutheastern of Inner Mongolia
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 995-1005 )