辽宁青城子榛子沟脉状铅锌矿成矿流体地球化学初探  

Preliminary study of geochemical characteristics of ore-forming fluid in Zhenzigou veined Pb-Zn deposit,Qingchengzi,Liaoning Province

作　　者：马玉波[1] 邢树文[1] 张增杰[1] 孙景贵[2] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]吉林大学地球科学学院,吉林长春130061

出　　处：《矿床地质》2012年第3期569-578,共10页Mineral Deposits

基　　金：国家自然科学基金项目(编号:41202042);地质矿产调查评价专项项目(编号:1212011085530)的联合资助

摘　　要：位处华北地台北缘东段辽吉裂谷内的青城子矿区是中国重要的铅锌矿集区,产出有多处中、小型铅锌矿床,榛子沟铅锌矿床是其中的典型代表之一。该矿床赋存于古元古界辽河群浪子山组与大石桥组界面或浪子山组层间及大石桥组第三岩性段的大理岩中或斜长角闪岩、黑云母片岩与含石墨(条带)大理岩接触处靠近大理岩的一侧,矿体呈层状-似层状和脉状。文章对该矿床脉状矿体的稠密浸染状矿石的流体包裹体及其氢、氧同位素地球化学进行了研究,结果表明,成矿流体受到了后期热液系统中大气降水的混入,是一套H2O-CO2-NaCl流体体系。流体包裹体液相成分分析表明,成矿流体既具有岩浆热液的特点,又具有大气降水(或地层流体)的特点。石英内流体包裹体的δD为-85‰^-100‰、δ18OH2O值为1.85‰~4.45‰,表明成矿流体后期受大气降水的混入,致使氧同位素值朝大气降水方向漂移,偏离了正常岩浆水值。经综合分析认为,榛子沟铅锌矿床成矿期的成矿流体为大气降水与岩浆水混合成因。The Qingchengzi orefield lies in Liao-Ji rift valley,eastern block of the North China Craton,and the Zhenzigou Pb-Zn deposit is a typical medium and small sized Pb-Zn deposit in this area.The Zhenzigou Pb-Zn deposit mainly occurs in Dashiqiao Formation,on the marble or near-marble side of the contact zone between amphibolites,biotite schist and graphitic marble,with the main ore types being stratiform-stratoid ore body and veined ore body.The authors chose the massive disseminated ore in the veined ore body and analyzed its fluid inclusion gas-liquid phase components.The results show that the ore-forming fluid was probably a H2O-CO2-NaCl system with the addition of later meteoric water.Besides,liquid phase component analysis also shows that the ore-forming fluid has multiple-source characteristics of both magmatic hydrothermal fluid and meteoric fluid.An analysis of δD and δ18OH2O shows that the late stage meteoric water infiltrated into the ore-forming fluid and result in ＂oxygen deviation＂ toward the meteoric water.Multidisciplinary analysis suggests that the ore-forming fluid of the metallogenic phase was a multiple-source fluid resulting form the mixture of magmatic hrdyothermal fluid and meteoric water.

关 键 词：地球化学 成矿流体 氢、氧同位素 榛子沟脉状铅锌矿 青城子 辽宁 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]