水口山铅锌矿成因探讨  

Genesis of the Shuikoushan lead-Zinc deposit,Changning City,Hunan Province

作　　者：路睿[1] 徐兆文[1] 陆建军[1] 王汝成[1] 左昌虎[1] 赵增霞[1] 缪柏虎 

机构地区：[1]内生金属矿床成矿机制研究国家重点实验室,南京大学地球科学与工程学院,南京210093

出　　处：《南京大学学报（自然科学版）》2013年第6期732-746,共15页Journal of Nanjing University（Natural Science）

基　　金：国家重点基础研究发展计划项目(2012CB416705);中国地质调查局调查项目(1212011085407)

摘　　要：本文在详细的野外地质工作基础上,运用流体地球化学和同位素地球化学方法,通过流体包裹体和S、Pb、C-O同位素研究,探讨水口山铅锌矿床形成的物理化学条件和物质来源.显微测温表明:水口山铅锌矿床含矿方解石流体包裹体均一温度介于92℃~345℃之间,盐度介于0.35%~19.84%NaCl eq.之间;流体密度介于0.668~1.083g/cm3之间,均值为0.929g/cm3;估算流体压力约18.3MPa,推测成矿深度约1.8km.矿石δ34S介于-2.42‰^-0.23‰之间,均值为-1.10‰,说明矿石中的硫主要来源于岩浆,并可能受到地壳物质混染.矿石206 Pb/204 Pb介于18.444~18.538之间,均值为18.150;207Pb/204Pb介于15.654~15.783之间,均值为15.726;208Pb/204Pb介于38.627~39.066之间,均值为38.872,表明矿石中的铅主要来源于地壳.地层中灰岩的δ13CVPDB介于-0.50‰~0.30‰之间,均值为0‰,δ18OSMOW介于14.10‰~16.80‰之间,均值为15.50‰;含矿方解石δ13CVPDB介于-1.80‰^-0.70‰之间,均值为-1.30‰,δ18OSMOW介于15.00‰~16.50‰之间,均值为16.00‰.矿石碳、氧同位素与地层灰岩中碳、氧同位素值大致相近,表明矿石中碳主要来源于上古生代的灰岩.综合流体包裹体研究和同位素示踪结果,并参照前人研究成果,认为水口山铅锌矿床形成于浅成低温环境,成矿物质主要来源于地壳.Based on field geological investigation, comprehensive study of fluid inclusions and C-O isotopes for ore-bearing calcites, and S-Pb isotopes for ore sulfide are conducted, this paper discussed the ore-forming physicochemical conditions, the metallogenic material source, and genesis of the Shuikoushan lead-zinc deposits. Homogenization temperatures of fluid inclusions range from 92℃to 345℃ in ore-bearing calcites , with the salinities ranging from 0.35% to 19.84% NaCl eq.. The density of fluid inclusions ranges from 0.668 g/cm3 to 1.083 g/cm3 , with an average value of 0.929g/cm3. δ34S values of ore range from -2.42 ‰ to -0.23 ‰ , with an average value of -1.10‰ , indicating a deep source for magma and maybe partly contaminated by the crustal substance. Ore 206Pb/204Pb values range from 18.444 to 18.538, with a mean value of 18.150 ; 207Pb/204Pb values range from 15.654 to 15.783, with a mean value of 15.726 ; 208Pb/204Pb values range from 38.627 to 39.066 , with a mean value of 38.872, indicating a mainly upper crust source. Value of δ13 C VPDB of limestone in stratum values range from -0.5 ‰ to 0.3 ‰ , with an average value of 0 ‰ , δ18 O SMOW values range from 14.1 ‰ to 16.8 ‰ , with an average value of 15.5 ‰ ; δ13 C VPDB of ore-bearing calcites values range from -1.8 ‰ to -0.7 ‰ , with an average value of -1.3 ‰ , δ18 O SMOW values range from 15.0 ‰ to 16.5 ‰ , with an average value of 16.0‰ ; The similar C-O isotopic compositions of ore-bearing calcites and the limestone in Early Paleozoic stratum infers their affinity in source. According to the above data of fluid inclusions and the stable isotope , we can conclude that the mineral sources of the Shuikoushan lead-zinc deposits predominantly derived from the earth crust, and the deposits was formed in a low temperature epithermal environment

关 键 词：流体包裹体 稳定同位素 矿床成因 水口山铅锌矿 湖南省常宁市 

分 类 号：P618.42[天文地球—矿床学]