辽宁青城子铅锌矿成矿流体特征和成矿物质来源示踪

青城子铅锌矿地处辽东-吉南裂谷带西端,是中国东北地区著名的铅锌矿床,其成矿作用复杂。为了深入揭示该矿床的成矿流体特征和成矿物质来源,本文在对青城子铅锌矿床(喜鹊沟、甸南、本山)地质特征研究的基础上,开展了流体包裹体测温和激光拉曼成分分析,H、O、C、S、Pb同位素分析,并进行了多元同位素体系的综合示踪。青城子铅锌矿床发育富液相包裹体,局部发育H_2O-CO_2三相包裹体。成矿温度范围大,是多阶段成矿作用发展演化的反映(至少两期成矿),成矿温度主要在190℃~310℃之间,应属中温成矿,成矿流体为中温低盐度的水盐流体。激光拉曼成分特征,成矿流体总体属于含CH_4的H_2O-CO_2-NaCl体系,属于还原性流体,具有深源的特征。氢氧同位素结果显示,成矿热液主要来源于岩浆水和大气降水。硫同位素特征表明,矿体中的硫可能主要来自海水硫酸盐的还原。碳氧同位素特征表明,成矿物质可能起源于地层,后期发生岩浆热液改造。铅同位素结果表明,矿石中铅是地层与岩浆岩的混合源铅。

Characteristics of mineralization fluids and tracers of mineralization material sources of the Qingchengzi lead-zinc deposit in Liaoning Province

The Qingchengzi lead-zinc deposits are located in the western Liaodong-Jinan rift,a famous mine in Northeast China with complex mineralization.The purpose of this work was to further reveal the characteristics of mineralization fluids and mineralization material sources,Based on geological research of the deposits (Xiquegou,Diannan and Benshan),we have conducted fluid inclusion temperature measurement and laser Raman component analysis,H,O,C,S,and Pb isotope analysis,and established a comprehensive multivariate isotopic tracer system.Results show that the Qingchengzi lead -zinc deposits contain liquid-rich inclusions,locally with three-phase development of H2O-CO2 inclusions.The mineralization temperature range was large,representing the multi-stage (at least two periods) mineralization of evolution.The main mineralization temperature was between 190℃ ～310℃,attributed to medium-temperature mineralization.The ore-forming fluids were of low salinity water with medium temperature.Laser Raman compositional characteristics show that ore-forming fluids generally belong to the CH4-bearing H2O-CO2-NaC1 system,reducing fluids,which have deep sources.The results of hydrogen and oxygen isotope analysis show that the thermal mineralization fluids might come from magmatic water and atmospheric precipitation.Sulfur isotopic characteristics show that the sulfur in orebodies might come from seawater sulfate reduction.The results of carbon and oxygen isotopes suggest that the ore-forming minerals may have originated from strata with late magmatic hydrothermal alteration.Lead isotope results indicate that the lead has a mixed source of strata and magmatic rocks.