西藏蒙亚啊铅锌矿床金属硫化物、石英稀土元素组成特征及其成因研究

蒙亚啊铅锌矿床自发现至今尚未报道稀土元素地球化学的研究成果,本文通过ICP-MS方法测定了矿床金属硫化物和热液成因石英中稀土元素的组成。研究表明,磁黄铁矿、黄铜矿、闪锌矿和方铅矿中稀土元素总量有所差异,但总体均为右倾的轻稀土富集型配分模式;据Eu异常特征可将其分为3组,Eu异常的产生主要是成矿过程中物化条件的转变及方解石的大量结晶造成的。4件石英稀土元素总量亦有所差异,原因在于其结晶时间和结晶温度不同,其配分曲线亦为轻稀土富集的右倾型;不同阶段形成的石英各自具强烈的正铕或负铕异常,究其原因主要是由于后期大气降水的加入及方解石的形成引起的。

A study of metallic sulfides, quartz REE composition characteristics and genesis of the Mengya'a lead-zinc deposit

No research results of RRE geochemistry have so far been reported since the discovery of the Mengya’a Pb-Zn deposit.In this paper,the REE compositions of metallic sulfides and hydrothermal quartz from this ore deposit were determined by ICP-MS.Studies show that pyrrhotite,chalcopyrite,sphalerite and galena are somewhat different in REE amount,but they all have the distribution patterns of rightly-oblique LREE enrichment type.According to the Eu anomaly,these metallic sulfides can be divided into 3 groups,and the Eu anomalies are mainly caused by the transformation of physical and chemical environment in the ore-forming process and the mass crystallization of calcite.There also are differences of REE amount in 4 quartz samples due to their difference in crystallization time and temperature,and their distribution patterns are also of the rightlyoblique LREE enrichment type.Meanwhile,the quartzes formed at different stages have their strong positive or negative Eu anomalies separately,which is attributed to the addition of later meteoric water and the formation of lots of calcites.