摘要
东坡柴山-蛇形坪一带铅锌矿床位于千里山岩体西南侧的远接触带上,由脉状、柱状和席状的铅锌矿体组成,在矿体周围明显发生碳酸盐化和硅化作用。该带矿床中闪锌矿、萤石、石英和方解石内流体包裹体类型主要包括富液相包裹体、富气相包裹体和含子矿物包裹体;其流体包裹体的均一温度范围为140~395℃,在350℃、240~260℃和200~220℃处分别出现峰值,反映该期热液流体在形成脉状、柱状铅锌矿体过程中可能包含了不同的捕获事件,其中方解石内出现的气体包裹体同与其共生的液体包裹体的均一温度相近,两者均一温度范围主要集中在268~395℃,峰值为350℃,液相包裹体w（NaCleq）范围为9%~11%,表明流体发生过气液相分离的沸腾作用;闪锌矿、萤石、石英和方解石中流体包裹体w（NaCleq）范围为0~23%,峰值9%~10%。流体包裹体的均一温度和盐度特征与岩浆热液流体演化到裂隙阶段静水压力条件下的流体相近。闪锌矿中流体包裹体内存在方解石和白云石子矿物,表明铅锌矿的成矿作用发生在富集碳酸盐的热液流体中。千里山花岗岩体晚期释放的流体沿着不同的通道上升,当它冷却到低于400℃,这些地区产生了脆性裂隙,流体沿着裂隙继续上升,并且发生沸腾作用,因此,温度在340~400℃时,w（NaCleq）为7%左右的流体分成了w（NaCleq）约10%的液相流体和w（NaCleq）约0.02%的气相流体,由于温度和压力的迅速降低,成矿物质沿着裂隙和空洞沉淀成矿,形成了东坡矿区的脉状、柱状和席状的铅锌矿体。
The Chaishan-Shexingping Pb-Zn deposits of Dongpo are located in the distal areas of southeast Qianlishan intrusions and comprise Pb-Zn veinlike,columnar and sheet ore bodies,which have been apparently subjected to the alteration of carbonation and silicification.The fluid inclusions in sphalerite,fluorite,quartz and calcite of the Chaishan-Shexingping Pb-Zn deposits of Dongpo are composed of liquid-rich,gas-rich and daughter mineral-bearing inclusions.The homogenization temperatures of fluid inclusions in these minerals range from 140℃ to 395℃,with peaks being 350℃,240~260℃ and 200~220℃,respectively,corresponding to various capture events of hydrothermal fluids in the formation processes of Pb-Zn veins and columns.The homogenization temperatures of gas-rich and liquid-rich inclusions in calcite are roughly similar,both concentrated between 268℃ and 395℃ with the peak being 350℃,and the salinities w（NaCleq） of the coexistent liquid inclusions range from 9% to 11%,confirming boiling and separation of gas and liquid phases.The salinities w（NaCleq） of fluid inclusions in these minerals range from 0 to 23%,with the clear peaks between 9% and 10%.The homogenization temperatures and salinities of fluid inclusions are consistent with those of magmatic-hydrothermal fluids at the evolution stage of cracks and hydrostatic pressure.There are some daughter minerals,like calcite and dolomite,in fluid inclusions in sphalerite,reflecting Pb-Zn mineralization in the carbonate-rich hydrothermal fluids.The late fluids released by Qianlishan granite migrated upward along different paths,and when they were cooled below the temperature of 400 ℃,brittle fractures would occur,and the fluids along the fractures continued ascending,so fluid boiling occurred.The fluids with temperatures between 340℃ and 400℃ and salinities w（NaCleq） of 7% would separate into liquid fluids with salinities of about 10% and gas fluids with salinities w（NaCleq） of about 0.02%,and due to the decrease of temperature and pressuree,the materials for mineralization deposited along cracks and voids,forming Pb-Zn veins,sheets and columns in Dongpo area.
出处
《矿床地质》
CAS
CSCD
北大核心
2012年第2期216-228,共13页
Mineral Deposits
基金
国土资源部公益性行业科研专项经费项目“我国典型金属矿科学基地研究(编号:200911007-11)”
国土资源部成矿作用与资源评价重点实验室开放基金(ZS1112)的联合资助
国家重点基础研究发展规划项目(编号:2007CB411405)
关键词
地球化学
流体包裹体
沸腾
岩浆热液
铅锌矿床
柴山-蛇形坪
东坡
geochemistry
fluid inclusions
boiling
magmatic hydrothermal fluids
Pb-Zn deposits
Chaishan-Shexingping
Dongpo
