内蒙古赤峰山湾子金矿流体包裹体和年代学研究  

A study of the fluid inclusions and chronology of the Shanwanzi gold deposit in Chifeng,Inner Mongolia

作　　者：李伟[1] 江斌[1] 刘淼[1] 陈井胜[1,2] 李斌[1] 杨帆[1,2] 张渝金[1,2] 刘世峰 蔡闹 LIWei;JIANG Bin;LIU Miao;CHEN Jingsheng;LI Bin;YANG Fan;ZHANG Yujin;LIU Shifeng;CAI Nao(Shenyang Center of China Geological Survey,Shenyang 110034,Liaoning,China;College of Earth Science,Jilin University,Changchun 130061,Jilin,China;Liaoning Technical University,Fuxin 123000,Liaoning,China;Stony Brook University,Stony Brook,NY 11794,USA)

机构地区：[1]中国地质调查局沈阳地质调查中心,辽宁沈阳110034 [2]吉林大学地球科学学院,吉林长春130061 [3]辽宁工程技术大学矿业学院,辽宁阜新123000 [4]纽约州立大学石溪分校,纽约长岛11794

出　　处：《中国地质》2020年第2期394-405,共12页Geology in China

基　　金：中国地质调查局项目(DD20190039-06,DD20160048-04)资助。

摘　　要：内蒙古赤峰山湾子金矿床位于赤峰—朝阳金成矿带东部,产于早白垩世义县组一段安山岩中。为了研究该矿床成矿年龄及成因特征,本文对该矿床流体包裹体岩相学,显微测温,氢、氧同位素和年代学研究表明:流体包裹体主要以纯液相包裹体为主,少量气-液两相包裹体。包裹体气体成分主要是H2O和CO2,反应了成矿流体为NaCl-H2O-CO2体系。均一温度变化范围为219~49℃,盐度为0.35%~3.23%NaCleqv,属于低温低盐度范畴。成矿压力为2.7~33.8 MPa,成矿深度为2.78 km左右,表明矿床具浅成特征。利用LA-ICP-MS方法锆石U-Pb测年,获得赋矿围岩安山岩的形成年龄为(123.59±1.0)Ma和(124.5±0.68)Ma,对成矿时代进行了限制,即成矿时代不早于早白垩世。综合矿床地质特征和成矿流体研究,认为山湾子金矿床属低硫化浅成低温热液型矿床。The Shanwanzi gold deposit in Chifeng of Inner Mongolia which is located in the east of Chifeng-Chaoyang gold metallogenic belt occurs in the andesite of the early Cretaceous Yixian Formation.In order to discuss the metallogenic age and genetic characteristics of the deposit,the authors,through the study of petrography,microthermometry,hydrogen,oxygen isotope and chronology of the the fluid inclusions,have reached the following conclusions:The fluid inclusions are mainly composed of pure liquid inclusions and a small amount of gas-liquid two-phase inclusions,and the gas composition of the inclusions is mainly H2O and CO2,which reflects the NaCl-H2O-CO2 system;uniform temperature range is 219-249℃,and salinity is 0.35%-3.23%NaCl eqv.,suggesting that the temperature and salinity of the principal metallogenic period is low;the metallogenic pressure is 2.7-33.8MPa,and the metallogenic pressure depth is 2.78 km,indicating that the mineralization exhibits a shallow characteristic;the formation age of andesite determined by ICP-MS U-Pb zircon is 123.6 Ma and 124.5 Ma,which is consistent with the age of early Cretaceous period of the Chaoyang-Chifeng gold metallogenic belt.Combining ore deposit characteristics with the study of the metallogenic fluid,the authors hold that the Shanwanzi gold deposit is a low sulfur,low temperature hypabyssal hydrothermal deposit.

关 键 词：流体包裹体 山湾子金矿 低硫化浅成低温热液型矿床 成矿流体 义县组一段安山岩 矿产勘查工程 内蒙古 

分 类 号：P618.51[天文地球—矿床学]