| 其他摘要 | Huangshaping deposit is a typical skarn-type polymetallic deposit, which is also an important part of the Nanling polymetallic mineralized belt. Different types of assemblages of metal elements are well developed in mining area. Thus, it is an ideal object for researching ore-forming fluid evolution and genesis. Moreover, it also can provide evidence for coupling relationship between the extensive magmatic activity in Yanshanian period in south China and W-Mo-Cu-Pb-Zn polymetallic mineralization, and its deep dynamical mechanism.This doctoral dissertation is focused on granites and associated polymetallic deposit in Huangshaping, respectively. Based on research of petrology, elemental geochemistry, isotopic geochemistry and fluid inclusions, we mainly discussed the petrogenesis and tectonic setting of the granitic intrusion in this area, the sources of ore-forming materials and fluids, metallogenic chronology, ore-forming fluid evolution, as well as the corresponding metallogenic geodynamic setting. Finally, following preliminary knowledge of ore genesis and ore forming process is obtained. 1. Fluid inclusion data show that the fluid property of different mineralization types varies widely. The fluid inclusions in garnet and actinolite are characterized by coexisting brine and vapor-rich fluid inclusions, also, high homogenization temperatures ( 528℃ to ＞ 600℃) and pressure 600~800 bar) , indicating that immiscible condition occurred during early stage and fluid exsolved directly from magma. Tungsten mineralization from later skarn stage was characterized by fluid inclusion with high temperature ( 400～460℃) ，high salinity ( 40%～45% NaCleqv). The pressure is estimated to be 200～400bar. At the sulfide stage，molybdenum mineralization was characterized by fluid inclusion with temperature from 300~ 340℃, salinity from 12~14% NaCleqv and pressure from 100~200bar.The fluid inclusions associated with Zn-Pb mineralization are almost liquid-rich fluid and the ore-forming temperature drops to 240~160℃ and salinity shows mainly between 4~10％ and 14~18％NaCl eqv. The process of crystallization of skarn minerals, scheelite and mineralization of later sulfides are controlled by fluid related to magma intrusion. In General, different types of fluids formed under wide range of temperatures and pressures representing different mineralization stages indicate that characteristics of ore-forming fluid were controlled by different evolution paths of supercritical fluid exsloved from deep magma chamber. Oxygen fugacity of ore-forming fluid decreased gradually from early to late metallogenic stage. While Cu mineralization(Cu，Cu-Mo，Cu-W) was formed by another stage of fluids, different from W-Mo-Pb-Zn mineralization. 2.The radioactive age of zircons by LA-ICP-Ms U-Pb dating method and Re-Os dating of the molybdenite were repoorted from the Huangshaping polymetallic deposit. The results show that different types of granitic plutons are of similar ages. Mineralization age is coincide well with the intrusion age of granitic plutons, both of which belong to the production of late Jurassic period. Based on the field inverstigation, petro-geochemical data, we concluded the evolutionary sequence of the Huangshaping granites. 3. Systematic studies of Pb isotopes of oxides(scheelite), sulfides (galena, sphalerite, pyrrhotite and molybdenite) and gangue mineral(calcite and fluorite) ;S isotopes of sulfides (galena, sphalerite, pyrrhotite and molybdenite) and C-O isotopes of calcite and associated gangue minerals from different mineralization stages argue that ore-forming materials were mainly derived from the magma, which was the production of the remelting of the deep crust caused by upwelling of the mantle source material. And also, sedimentary rocks contributed small part of ore-forming materials. There were different characteristics between Cu mineralization and W-Mo-Pb-Zn mineralization. The former shows higher proportion of ore-forming m |
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