东准噶尔强应变构造带成矿系统的特征、成矿流体和热动力条件分析

东准噶尔强应变构造带形成于板块构造的特定部位 ,是不同级别板块俯冲、碰撞作用的产物 ,控制着该区大部分内生金矿的分布 ,并构成了该区最重要的金成矿系统 .在洋壳俯冲和洋盆闭合阶段陆缘火山岩浆弧、残余海盆和俯冲带上形成的陆缘 -火山碎屑沉积相、含碳质沉积相及混杂蛇绿岩块等是金丰度较高的地质体 ,构成了成矿系统潜在的矿源层 (体 ) .构造运动产生的和深部上升的热能是成矿系统中岩石强烈变形变质和Au活化的能源 .构造带内由于应力的差异驱动成矿流体从强烈挤压地段向相对低压的伸展区迁移 ,使金矿床 (点 )集中分布于二者过渡带附近 .矿体及矿脉则形成于构造带较晚阶段形成的次级断裂及裂隙中 .

CHARACTERISTICS AND METALLOGENIC FLUID AND THERMODYNAMIC CONDITION ANALYSIS OF METALLOGENIC SYSTEM IN HIGHLY STRAINED STRUCTURAL BELT, EAST JUNGGAR

The highly strained structural belts in some units of palaeo plate tectonics, products of subduction and collision of various scale plates in East Junggar, controlled the distribution of the majority of the endogenetic gold deposits and occurrences,turning into the most important gold metallogenic system in East Junggar. The epicontinental volcanic magma arcs and residual sea basins that occurred at the stages of the oceanic crust subduction and oceanic basin closure, and the epicontinental volcaniclastic sedimentary facies, the carbonaceous sedimentary facies and the melange ophiolite blocks that occurred on the subduction zone are all included in the geological bodies with higher Au abundance, constituting the potential source beds (bodies) in the mineralization system in the highly strained structural belt. The thermal energy produced by the tectonic movement and derived from the deep structure is a kind of energy resource resulting both from the violent deformation and metamorphism and from the Au activation in this mineralization system. The ore forming fluids, driven by the stress difference within the tectonic zone, migrated from the violent compression zones to the extension zones with relative lower pressure and stress, resulting in the concentration of the gold deposits (occurrences) near the transitional zones between these two structural belts. The gold bodies and veins thus occurred in the secondary faults and fissures derived from these structural belts.