The Wulaga gold deposit, located in the northeastern edge of the joint of Paleo-Asiatic and Pacific tectonic domains, is one of the most important gold deposits in China. The ore bodies are mainly hosted in secondary faults of the Wulaga fault, and cryptoexplosive breccia zone within the Tuanjiegou plagioclase granite-poiphyry, and in the layer fractures of metamorphic Heilongjiang Group. There are three types of fluid inclusions in quartz phenocryst of plagioelase granite-porphyry, that is, melt inclusions, primary L-V and L-V-S inclusions, as well as secondary L-V inclusions. Classy melt inclusions are characterized by acid magma (SiO2 -69. 5% -73. 8% ), with the trapping of temperatures higher than 800X1. Secondary L-V inclusions in quartz phenocryst have 210 -350℃ of homegenization temperatures (Th), which represents the features of sub-volcanic hydrothermal fluids and are coincide with those of pyrite-white chalcedony quartz stage (Ql), while salinities (5% -7% NaCleqv) are slightly higher than those of Ql. Gold mineralization of the Wulaga can be divided into three stages. Fluid inclusions in pyrile-early white chalcedony quartz stage (stage I) are characterized by aqueous solution with homogenization temperatures of 154 - 355℃ , mainly in 230 ~ 270℃. Salinities of fluid inclusions are 1.3% ~8. 2% NaCleqv, with densities of 0. 53 ~0. 88g/cm3. Homogenization temperatures of fluid inclusions in smoky gray chalcedony quartz-polymetallic sulfide stage (stage II) are 159 - 196℃, mainly in 170 ~ 190℃ , with salinities of 2. 2% ~3. 2% NaCleqv and densities of 0. 79 ~0. 92g/cm Those in calcite of carbonate-quartz stage (stage III) are mainly in 170 ~ 270℃ , with salinities of 0. 5% ~ 2. 9% NaCleqv and densities of 0. 80 ~ 0. 88g/cm3. Ore-forming fluids in the main mineralization stage are characterized by mid to low temperatures, low salinities, and lack of CO,, which is similar with epithermal deposit related with continental volcanic-subvolcanic rocks in the world. Melt and fluid inclusion study show that gold mineralization has a close relationship with plagioclase granite-porphyry, and it is possible for silicate magma to produce salt-aqueous solution through immiscibility in magmalic differentiation. The Wulaga gold deposit should belong to epithermal gold deposit related to Cretaceous plagioclase granite-porphyry.%黑龙江乌拉嘎金矿是我国陆相火山岩区的重要金矿之一.构造位置处于古亚洲构造域与滨太平洋构造域交接复合部位的东北缘,矿体主要分布于团结沟斜长花岗斑岩接触带部位的隐爆角砾岩带和黑龙江群变质岩的层间裂隙中.斜长花岗斑岩的石英斑晶中发育3类包裹体:熔体包裹体、原生的L-V包裹体(及少量的L-V-S包裹体)和次生的L-V包裹体.玻璃质熔体包裹体相当于酸性残浆的成分(SiO2达69.5％～73.8％),其捕获温度大于800℃.石英斑晶中次生L-V包裹体均一温度集中在210～350℃、盐度5％ ～7％NaCleqv,代表了次火山岩浆热液的特征,与黄铁矿-早期白色玉髓状石英阶段中Q1的包裹体均一温度范围很接近,而盐度略高于白色玉髓状石英Q1的.乌拉嘎金矿的金成矿可划分3个成矿阶段,发育盐水溶液包裹体:(1)黄铁矿-早期白色玉髓状石英阶段,包裹体均一温度为154～355℃,集中在190 ～ 330℃,盐度为1.3％ ～8.2％NaCleqv,密度为0.53～0.88g/cm3.(2)烟灰色玉髓状石英-多金属硫化物阶段,石英中包裹体均一温度为159～196℃,集中在170～190℃,盐度为2.2％ ～3.2％ NaCleqv,密度0.79～0.92g/cm3.(3)碳酸盐-石英阶段,方解石中包裹体均一温度集中在170～270℃:盐度0.5％ ～2.9％ NaCleqv.成矿流体以中低温、低盐度、贫CO2的盐水体系为特征,与国内外陆相火山-次火山热液矿床十分相似.石英斑晶中熔体、流体包裹体及其共存反映了次火山岩浆活动晚期,由硅酸盐熔体通过不混溶产生含矿的盐水溶液的可能,说明了金成矿与斑岩的成因联系,乌拉嘎金矿应该属于陆相火山-次火山活动有关的中低温浅成热液金矿床.
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