中文摘要：

西藏双湖县商旭金矿床位于班公湖—怒江缝合带的中段，矿体受近东西—北西西的断裂构造控制，呈脉状、透镜状产于下—中侏罗统木嘎岗日群浅变质复理石中，矿石类型主要为石英脉型与蚀变岩型。本文在野外地质调查的基础上，对不同成矿阶段的石英脉进行了流体包裹体的岩相学观测、显微测温、成分分析以及H—O同位素测试。流体包裹体结果表明，主成矿阶段的流体温度为195~230℃；盐度为2%～9% NaCleqv，密度为0.88～0.95 g/cm3；气相成分以H2O为主，含CO2、N2及少量的CH4；液相成分主要为Ca2＋、Na＋、C1-。总的来看，商旭岩金矿床成矿流体为中低温、低盐度、低密度、含CO2的CaCl2—NaCl—H2O体系流体，具有典型的造山型金矿床成矿流体的特征。氢氧同位素结果分别为：δDH2O, V-SMOW为-104‰～-136‰、δ18OH2O, V-SMOW为4.92‰～7.82‰，显示出变质水与大气水混合的特征。综合讨论认为，商旭金矿床成因类型为造山型金矿，流体从封闭体系进入开放体系的减压沸腾，是金沉淀的主要机制。

英文摘要：

Objectives： The Shangxu gold deposit in Shuanghu county of Tibet is located in the middle segment of Bangong Co—Nujiang suture belt. Ore bodies controlled by the nearly EW—NWW fractures occur as veins and lens in the Lower—Middle Jurassic Mugagangri Group which is mainly composed of metamorphic flysh, quartz veins type ore and altered rock type ore coexist. Methods： On the basis of detailed geological fieldwork, we selected quart veins in different mineralization stages for the study of fluid inclusion including petrographic characteristic observation, micro temperature measurement, composition analysis and the test of the hydrogen and oxygen isotope. Results： Fluid inclusion studies show that the temperature of the fluid in main mineralization stages ranges from 195 to 230°C, the salinity from 2 to 9 wt% NaCl equiv and the density from 0.88 to 0.95 g/cm3.The content of gas phase primarily contains H2O, CO2 and N2 with a small amount of CH4, and the liquid part mainly contains Ca2＋, Na＋, Cl-. The ore forming fluid of the Shangxu gold deposit belongs to CaCl2—NaCl—H2O fluid system with content of CO2, low to moderate homogenization temperature, low salinity and low density, which are similar to those of typical orogenic gold deposits. According to the hydrogen and oxygen isotope test, the δDH2O, V-SMOWvalues of fluid inclusions in auriferous quartz veins range from -104‰ to -136‰, and δ18OH2O, V-SMOW from 4.92‰to 7.82‰, indicating a mixture of metamorphic water and meteoric water.  Conclusions： The Shangxu gold deposit may be an orogenic gold deposit formed under continental collisional background, and decompression caused by the migration of fluid from closed to open system is the main mechanism for the depositing of gold.