摘要
位于四川西北部的马脑壳金矿床为陕甘川金三角区内一重要矿床,许多学者对其进行过大量的研究,对其地质地球化学特征有了较为全面的认识,同时对矿床的成因也做了多方面的探讨。为了确定矿床的成矿时代,从层状矿体中采集了富含流体包裹体的石英矿物。通过测定包裹体的Rb-Sr同位素组成,应用ISOPLOT程序计算获得(210±35)Ma的成矿年龄,该年龄与容矿地层的形成时代相近。流体包裹体的锶同位素初始比值与三叠纪时期海水的锶同位素比值相一致。综合矿体产出特征、矿石组构及区域构造演化历史,认为作为矿床主体的层状矿体是同生沉积的产物,脉状网脉状矿体则是由后期造山运动体制下所产生的成矿热流体沿裂隙构造交代充填所形成。
The Manaoke gold ore deposit,locate d in Northwest Sichuan Provin ce,is o ne of the important ore deposits in the triangle area of Shaa nxi-Gans u-Sichuan provinces.Much work has been taken by a great number o f researchers to recognize the geolog ical and geochemical characteristi cs of the deposit an d discuss the ore g enesis from different aspects.To determin e the mineralizat ion time of the deposit using the method of Rb-Sr isotopes,the quartz containi ng fluid inclusions was chosen from the sheetlike ore bod ies.The compositions of Rb-Sr isoto pes of the fluid inclusions were measured.Through the calculati on of ISOPLOT p rogram the ore-forming age of(210±35)Ma was obtained,w hich is close to the sedimentary age of the host rock.The initial 87 Sr/ 86 Sr ratio of the fluid inclusions is consistent with that o f coeval seawater .Combining the ore body feature,ore fabric,and the region tectonic environmen t,it is suggested that the main ore bodies occurred a s layers were formed by t he syn-sedimentation.On the other hand,th e vein and network ore bodies were formed through the hydrothermal system caused by orogeny.
出处
《地球化学》
CAS
CSCD
北大核心
2004年第1期94-98,共5页
Geochimica
基金
国家自然科学基金(49872038)
中国科学院"百人计划"资助项目
国土资源部资源环境攻关项目(95-02-002)
