Geological, Geochemical Characteristics And Mineralization Of Taipinggou Molybdenum Deposit, Inner Mongolia

Taipinggou Molybdenum Deposit locates in the northern Daxinganling metallogenic belt, where has a complex tectonic—magmatic evolution history. We carry out comprehensive analysis and researches on tectonic-magma-fluid- mineralization with methods of the major elements & trace elements, fluid inclusion, sulfur isotope and geochronology, as well as the chronology methods such as Re-Os, Ar-Ar and SHRIMPⅡ. The major points described as follows:1. The molybdenum mineralization of Taipinggou is mainly controlled by the inside and outside contact zones of porphyritic granite and rhyolitic tuff. Mineralization are mainly disseminated and quartz sulfide veinlet types. The main ore minerals are molybdenite, chalcopyrite, pyrite, etc., and the gangue minerals are mainly quartz. The representative wallrock alteration is propylitization.2.The researches of fluid inclusion show that the homogenization temperatures mainly fall in the range of 225-350℃, which shows that it’s a deposit of middle-low tempreture, the density of ore-forming fluid is about 0.6～1.0g/cm3, pressure about 400×105Pa, and ore-forming depth about 1.3km. It belongs to the low-density fluid. So the metallogenic materials deposit on shallow and low-pressure entironment, which is basically same as the characteristics of porphyry-type deposit.3.All theδ34S of S-isotope in pyrite are evident positive values, with narrow range of variation, about 2.08‰～4.14‰, average of 3.104‰, and range of 2.06‰, high uniformity. S-isotope obviously has the characteristics of deep-seated magma sources, so we conclude the metallogenic materials come from lower crust or upper mantle.4.The Re-Os dating shows that the mineralization age is about 130Ma, formed during the intermediate-acid tectonic-magmatic evolution of early cretaceous. The Ar-Ar isochrones reveal the age of porphyry is about 127.5±4.5Ma. SHRIMPⅡindicates the crystallizing age of porphyraceous granite is 131.49±1.1Ma. Three data are highly consistent.5.Taipinggou Molybdenum Deposit is a typical porphyry-type deposit.