Ore-Forming Fluid Features and Genesis of Shabaosi Gold Deposit in Mohe County,Heilongjiang Province
Li Liang
Sun Fengyue
Li Bile
Qian Ye
Xu Qinglin
Abstract：Uncertainty of genesis and ore-controlling condition are always the key restriction of ore-search breakthrough to Shabaosi gold deposit.For the metallogenic background,most scholars believe that it formed in the compressional setting of orogenic process,but few observe that related to the extensional tectonic system.In order to re-determine the genesis of Shabaosi gold deposit,ore-controlling structure,characteristics of ore-forming fluid and source of ore-forming materials are studied in this paper based on the detailed field investigation.The results of the study show that the ore bodies occuring in the tensional fractures are controlled by the large-scale detachment fault.As-bearing pyrite is discovered by SEM for the first time born with arsenopyrite and pyrite in the early metallogenic stage,which indicates that Shabaosi gold deposit formed in meso-thermal or slightly meso-hypothermal environment.Fluid inclusions in quartz grains are well developed mainly in gas-liquid phase.The fluid of major metallogenic stage is characterized by moderate homogenization temperature (peak 200-260 ℃),low salinity (average 5.56 % NaCl equiv.)and low density (average 0.87 g/cm3 ).Bubbles (vapor-phase)of the ore-forming fluid, belonging to H 2 O-CO 2-CH 4 system,are mainly composed of H 2 O,CO 2 and CH 4 .The sulphur are mainly derived from the magma with theδ34 S of pyrite in the early metallogenic stage ranges of -1.3‰ to 5.6‰,while a little are from strata.The sa-linity of ore-forming fluid descends as the temperature reduces.The mixing of different fluids leads the precipitation of ore-forming materials.Comprehensive studies suggest that Shabaosi gold deposit belongs to mesothermal vein gold deposit con-trolled by detachment fault,which is related to the tectonic setting of intensive crustal extension and the crust evolution invol-ving enormous mantle derived materials in the late Yanshanian period.
Keywords：Shabaosidetachment faultore-forming fluidmesothermal hydrothermal vein gold depositore deposit geology
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：14( 1163-1176 )