甘肃阳山金矿构造-流体-金成矿作用关系

[摘 要] 基于对甘肃省文县阳山金矿床的构造变形分析、石英组构分析及流体包裹体研究,探讨了阳山金矿床的形成过程和热液成矿机制,认为自三叠纪以来,该区先后经历了韧性、韧-脆性及两期脆性等多期构造变形演化过程,并伴随多次岩浆热液活动。流体包裹体显微测温结果显示本区的均一温度主要集中在265～290℃,215～240℃和165～190℃等三个区间,流体组份体系接近于NaCl-H₂O-CO₂体系,成矿流体密度估计在0.98～1.02g/cm³之间,成矿压力估计为89.6 MPa,流体包裹体盐度估计在0.7%～9.4% NaCl之间激光拉曼显示其主要成分为H₂O和CO₂,据不同类型包裹体共生组合及流体演化特征,认为不同流体的混合是导致大量金沉淀的主要原因。

Study on the Relationship of Structure-Fliud-Gold Mineralization in theYangShan Gold Deposit, Gansu Province

Based on the analysis of structural deformation,quartz geometric analysis and fluid inclusions,this paper studies the ore forming processes and hydrothermal mechanism of the Yangshan gold deposit in Gansu Province.The result shows that since the Triassic period,this deposit has experienced ductile,ductile-brittle and brittle deformation of multiple periods.Measurements of microscopic temperature of fluid inclusions show that homogenization temperatures of this area concentrated in three intervals:265～290 ℃,215～240 ℃ and 165～190 ℃.Fluid component systems are close to the NaCl-H2O-CO2 system.Ore-forming fluid density is estimated to be 0.98～1.02 g/cm3.Mineralization pressure is estimated to be 89.6MPa,and mineralization occurred at depths of 1.41～3.59 km.Salinity of fluid inclusions is estimated to be 0.7～9.4% NaCl.According to different types of fluid inclusion composition and evolution of symbiotic,mixing of different fluids may be the main cause for gold precipitation.