CAJ | 학술논문

采用电子探针显微分析(EMPA)和粉末X射线衍射(XRD)分析了采自乌拉山金矿床含金钾长石-石英脉、石英脉以及其他类型岩石中的100多个钾长石样品的化学成分和结果状态,并采用R和Q模式聚类分析、Spearman等级相关分析方法对实验数据进行了统计分析.结果表明,含金矿脉、岩浆热液脉和蚀变花岗岩中的钾长石为中等到最大微斜长石,其特征为K2O含量高,但相对而言,Na2O、CaO和BaO的含量低.其他岩石类型中的钾长石的化学成分和结果状态变化很大,可以从透长石、正长石到微斜长石,其特征为K2O的含量相对较低,但Na2O、CaO和BaO的含量相对较高.含金样品中的钾长石通常更富K2O,表明金的成矿作用与富钾的热液流体和碱质交代作用有关.乌拉山金矿床的成矿作用分为两个阶段,主要的含金钾长石-石英脉中的钾长石富K2O,形成温度为307～379℃,平均为353℃;第二阶段含金石英脉中的钾长石含K2O较低,形成温度为260～318℃,平均为281℃.这些结果表明成矿流体与岩浆热液作用有关,流体朝温度降低、K2O含量降低的方向演化,K2O含量高的热液流体和260～380℃的形成温度有利于金的成矿作用.
채용전자탐침현미분석(EMPA)화분말X사선연사(XRD)분석료채자오랍산금광상함금갑장석-석영맥、석영맥이급기타류형암석중적100다개갑장석양품적화학성분화결과상태,병채용R화Q모식취류분석、Spearman등급상관분석방법대실험수거진행료통계분석.결과표명,함금광맥、암장열액맥화식변화강암중적갑장석위중등도최대미사장석,기특정위K2O함량고,단상대이언,Na2O、CaO화BaO적함량저.기타암석류형중적갑장석적화학성분화결과상태변화흔대,가이종투장석、정장석도미사장석,기특정위K2O적함량상대교저,단Na2O、CaO화BaO적함량상대교고.함금양품중적갑장석통상경부K2O,표명금적성광작용여부갑적열액류체화감질교대작용유관.오랍산금광상적성광작용분위량개계단,주요적함금갑장석-석영맥중적갑장석부K2O,형성온도위307～379℃,평균위353℃;제이계단함금석영맥중적갑장석함K2O교저,형성온도위260～318℃,평균위281℃.저사결과표명성광류체여암장열액작용유관,류체조온도강저、K2O함량강저적방향연화,K2O함량고적열액류체화260～380℃적형성온도유리우금적성광작용.
More than one hundred K feldspars were collected from gold-bearing Vein Ⅰ (K feldspar-quartz vein)and Vein Ⅱ (quartz vein) as well as various other rock types in the Wulashan gold deposit, China. Chemical compositions of K feldspars were analyzed using electron microprobe analysis (EMPA). The powder X-ray diffraction (XRD) patterns of K feldspars were collected using Cu Kα source. Au contents of the corresponding ore samples were analyzed by fire assay. Q- and R-mode cluster analysis and Spearman rank correlation analysis of the experimental data were performed. The results indicate that K feldspars from gold-bearing veins, magmatic hydrothermal veins and altered wall rocks are intermediate to maximum microclines characterized by higher content of K2O, lower contents of Na2O, CaO and BaO, and relatively small variations in chemical compositions. K feldspars from other rock types are likely sanidine, orthoclase or microclines that show greater variations in chemical compositions and are characterized by lower content of K2O but higher contents of Na2O,CaO and BaO. K feldspars from auriferous samples are much richer in K2O, indicating that gold mineralization might have been related to potassic hydrothermal fluids and intense K feldspar metasomatism. There exist two gold mineralization stages in the Wulashan deposit. K feldspars from the major K feldspar-quartz veins are characterized by higher K2O and higher formation temperatures of 307～379℃ with an average of 353℃. K feldspars from the quartz veins of the second stage are characterized by lower K2O and lower formation temperatures of 260～318℃ with an average of 281℃. These results indicate that the mineralization fluids were associated with magmatic hydrothermal events and evolved toward lower temperatures and lower content of K2O, but the hydrothermal fluids of higher K2O and the temperatures of 260～380℃ may favor gold mineralization.