【作者】 韩春明； 袁万明； 于福生； 汤云晖； 保增宽；

【Author】 Han Chunming Yuan Wanming Yu Fusheng Tang Yunhui Bao Zengkuan Institute of High-Energy Physics, CAS, Beijing ,100039, China

【机构】 中国科学院高能物理研究所；

【摘要】 位于西秦岭川、陕、甘地区的大水金矿床,是具有卡林型特征的金矿床。矿床赋存于下三叠统马热松多组（T₂m）灰岩和印支期花岗闪长岩脉中,矿化受到NWW向和近NS向断裂严格控制,矿石矿物以赤铁矿、褐铁矿和黄铁矿为主,蚀变以硅化、绢云母化和褐（赤）铁矿化为特征。成矿作用可以分为原生成矿期和表生氧化-次生富集期。矿床成矿温度100～400℃,盐度2.70～9.10Wt%NaCl,密度0.875～970g/cm³,成矿深度1.422～3.555公里;早期成矿流体来源于岩浆水,晚期成矿流体为改造的大气降水;硫同位素组成特征表明该矿床成矿物质与矿区内花岗闪长岩有关,同时也有深部物质的参与。该矿床为多次构造～岩浆作用的产物,早期成矿作用发生于西秦岭碰撞造山期,晚期喜山期区域整体构造隆升使矿体金品位进一步提高,显示了该矿床多期次幕式成矿作用特征。更多还原

【Abstract】 Dashui large gold deposit is located in the south of western Qinling Moutains between Qinling orogenic zone and Songpan-Ganzi orogenic zone. It was controlled by NWW-trending fault zone. The host rocks of the gold mineralization is mainly Triassic altered limestone and adamellite dikes. The δ34S values of pyrite range from -1.8 to +4.5 per mil with a mean of 2.40‰ reflecting a deep source of sulfur. Oxygen isotope data of calcite in ores indicates that calcite has δ18O values ranging from -22.4 to -11.1 per mil The calculated δ18Owater values of calcite range from -4.32 to +8.33 per mil and the δD values range from -61.1 to -101 per mil, δD and δ 18OWater values suggesting that the ore fluids were mainly derived from magma in the early stage of mineralization. However, the values in the late mineralization stage decrease, indicating mixing of meteoric waters at the time of the mineralization. Homogenization temperatures of fluid inclusions are relatively low, falling between 100 and 400℃ and mostly between 150 and 200℃ with a peak value of 175℃ Salinities exhibit a wide range from 2.70 to 9.10 wt.% NaClequiv, with a mean of 4.88 wt.% NaClequiv In addition, the early gold mineralization occurred from 196Ma to 182. 8Ma, and late gold mineralization took place range from 72.15Ma to 41. 21Ma , based on the Rb-Sr isochron dating of inclusions from calcite in ores, it means that the Dashui gold deposit at least has twice gold mineralization.更多还原