北祁连山西段西柳沟铅锌矿稳定同位素特征  

Stable Isotopic Characteristics of Xiliugou Polymetallic Deposit in the Western Part of the North Qilian Mountains

作　　者：康鸿杰[1] 孙柏年[1] 刘晓煌[1,2] 李相传[1] 朱多录[1] 张维昕[3] 

机构地区：[1]兰州大学资源环境学院 [2]武警黄金第七支队,烟台264004 [3]武警黄金第七支队

出　　处：《高校地质学报》2008年第3期433-441,共9页Geological Journal of China Universities

基　　金：国家重点基础规划项目(2006CB701400);国家自然科学基金项目(40772012)联合资助

摘　　要：西柳沟铅锌矿位于北祁连山西段以钨、钼、铜、铅、锌等为主的多金属成矿带之西端。为探讨其成矿流体的来源,选择了该矿床主成矿期的9件矿石样品,挑选其单矿物,并对保存于石英中的原生包裹体做了D,O同位素分析,分析显示成矿流体的δDV-SMOW值为-47‰^-72‰;成矿期石英矿物的δ18O介于11.9‰~14.1‰之间,与石英平衡的热液水的δ18OH2O‰值为-0.79‰~3.64‰之间(包裹体均一温度平均值为190℃);矿体石英包裹体δ13CV-PDB‰值介于-6‰^-4.2‰之间。成矿流体包裹体的均一温度为126℃~384℃,集中于140℃~200℃;盐度ω(NaCleq)为1.05%~9.86%,多数为1.74%~6.45%。研究表明:西柳沟铅锌矿是浅成的中低温、低盐度、低密度岩浆期后热液型矿床,成矿流体来源主要是以岩浆水为主,大气降水为辅。A polymetallic deposit zone with W, Mo, Cu, Pb, Zn mineralization was found in the western part of the North Qilian Mountains. The Xiliugou polymetallic deposit is located in the western part of this polymetallie deposits zone. In order to discuss the source of ore-forming fluid of this deposit, the authors selected 9 ore samples of the main ore-forming stage from this deposit and measured their H, O, C isotopic compositions. The results show that the DV-SMOW‰ values of the ore-forming fluid are -47‰--72‰with very small variation. The 81SO values in the main stage vary between 11.9‰-14.1‰. The δ18OH20‰ values of the hydrothermal fluid equilibrated with quartz are -0.79‰ -3.64‰ （ the average homogenization temperature of the fluid inclusions is 190℃）. The 813C values of fluid inclusions captured in the quartz are -6‰--4.2‰, also with a small variation range. Mierothermometrie studies indicate that the homogenization temperatures and salinities of the fluid inclusions in the ore- forming stage range from 126 to 384℃ and from 1.05% to 16.45% NaC1 equivalent, respectively, with most values in the range of 140～200℃ and 1.74%～6.45% NaCl equivalent, respectively. It is shown that the Xiliugou polymetallic deposit is a shallow, low temperature, low salinity and low density hydrothermal deposit. The magmatie water is the main source of the ore-forming fluid, and the meteoric water is subsidiary.

关 键 词：北祁连山 稳定同位素 成矿流体 流体包裹体 

分 类 号：P611.134[天文地球—矿床学] P618.4[天文地球—地质学]