Fluids source,evolution and geological implications of the Tangshang Pb-Zn polymetallic deposit,Longquan,SW Zhejiang
The Tangshang Pb-Zn deposit is a medium-sized Pb-Zn polymetallic deposit recently discovered in the Wuyishan Cu-Pb-Zn polymetallic metallogenic belt in southwest Zhejiang.Its spatial output is controlled by fault structures,and its genetic type is not yet clear.In this paper,based on the detailed division of the mineraliza-tion stages,microthermometry,laser Raman and H-O isotope analysis were carried out on the fluid inclusions of different mineralization stages.Studies have shown that the formation temperature of the magnetite-quartz stage(Ⅰ)pre-ore period was 273-348℃,and the uniform temperature of the vein-like galena sphalerite stage(Ⅱ)during the main ore-forming period was 225-304℃,and the post-ore period was late.Stage Quartz-quartz vein stage(Ⅲ)homogeneous temperature is 139-163℃.Laser Raman analysis results show that the liquid phase composition of the ore-forming fluid in the main ore-forming stage is mainly H2O,and the gas phase composition contains a certain amount of CO2 in addition to H2O.The δDSMOW of quartz inclusions in the quartz veins is mainly concentrated at-72.5‰--78.9‰,the value of quartz δ18O V-PDB is-27.6‰--30.8‰,and the δ18OV-SMOW is concentrated at-0.6‰-2.5‰,indicating that the ore-forming fluid comes from magmatic fluid,and there is gradual addition of atmospheric precipitation during the mineralization process.Therefore,the deep part of the Tangshang Pb-Zn deposit may have the potential to further exploration for porphyry-type mineralization.
ore-forming fluidsH-O isotopesTangshang Pb-Zn depositporphyry mineralizationWuyishan metallogenic belt
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