塔里木北缘库鲁克塔格地块大金沟金矿流体包裹体特征:对矿床成因的启示

Fluid inclusions for Dajingou gold deposit of Quruqtagh block in northeatern Tarim:implication for ore genesis

在成矿地质背景和矿床地质特征研究基础上,对大金沟金矿主矿体中含矿石英脉流体包裹体开展了系统的岩相观察和显微测温工作。结果表明:大金沟金矿含矿石英脉中主要发育富液相的气液两相包裹体,偶见纯液相或气相包裹体。这些包裹体可分为低温高盐度(75℃~121℃,16.71 wt%NaCl^19.68 wt%NaCl)、低温低盐度(100℃~172℃,0.7 wt%NaCl^5.71 wt%NaCl)、中低温中低盐度(75℃~253℃,6.16 wt%NaCl^12.51 wt%NaCl)和高温中低盐度(331℃~420℃,4.96 wt%NaCl^12.51 wt%NaCl)等4类。大金沟金矿主成矿期流体包裹体的均一温度(75℃~253℃)和盐度(0.7 wt%NaCl^19.68 wt%NaCl)变化较大,且两者的相关性不明显,属典型的中低盐度流体体系,与造山过程相关的变质流体类似,表明该矿床可能为造山型金矿床。

O n the basis of the research on geological background and characteristics of Dajingou glod deposit,the authors conducted petrographic observation and microthermometry on fluid inclusions from the gold-bearing quartz veins. The results show that most fluid inclusions in the samples are liquid-rich two phase gas-liquid inclusions,occasionally pure liquid or gas inclusions. These liquid-gas phase inclusions could be divided to low temperature( 7 5〇C ?121°C) and high salinity (16.71 w t % NaCl ?19.68 w t % N a C l ) ,low temperature ( 1 0 0〇C ?172°C ) and low salinity (0? 7 w t % NaCl ?5. 71 w t % N a C l ),low-middle temperature ( 7 5〇C ?2 5 3〇C ) and lowmiddle salinity ( 6. 16 w t % NaCl ?12.51 w t % NaCl) and high temperature (331°C ?4 2 0〇C ) and low-middle salinity (4. 96 w t % NaCl ?12. 51 w t % NaCl) inclusions. Homogenization temperatures and salinity of these fluid inclusions vary from 7 5 °C to 2 5 3 °C and 0. 7 w t % NaCl to 19. 68 wt % NaCl, respectively, without obvious linear relationship between them. The research results show that the fluids of Dajingoud gold deposit is typical middle-low salinity fluid system, similar to the orogenic metamorphic fluid, which resembles orogenic gold deposits.