官房钨矿位于滇东南薄竹山岩体西南缘,矿体主要产于花岗岩与灰岩的接触部位,为一大型接触交代型白钨矿床。为揭示该矿床成因,在系统研究矿床地质特征的基础上,对与成矿密切相关的花岗岩、大理岩型矿石以及矽卡岩型矿石进行了稀土元素、微量元素分析。结果表明:矿区花岗岩具有高钾钙碱性岩特征,为地壳重熔型花岗岩;微量元素特征表现为矿石与花岗岩均富集大离子亲石元素Rb、Th、U、Pb,亏损高场强元素Nb、Ta、Sr,矿区花岗岩W含量是区内同类岩石的1.1~7.6倍,这为矿床形成提供了丰富的物质基础;矿石与花岗岩稀土元素特征显示明显的相似性,均表现为稀土元素总量高、较为明显的Eu负异常、不明显的Ce异常以及轻稀土元素富集的右倾型稀土元素配分曲线,进一步表明成矿作用与岩浆活动有着密切的成因关系。
Guangfang tungsten deposit is located in the southwest of Bozhushan granite,southeastern Yunnan.The orebodies are mainly produced in the contacts parts between granite and limestone,and is a large contact metasomatic type scheelite deposit.In order to reveal the metallogenesis,on the basis of a systematical study on the geological characteristics of deposit,the rare earth elements and trace elements of grantitc rocks,marble ores as well as skarn ores are analyzed in this study.The results show that the granite bears the features of high-K calc-alkaline granite,which belongs to crustal remelting granite.The trace elements are characterized by enrichment of large-ion lithophile elements such as Rb,Th,U,Pb and depletion of high field strength element such as Nb,Ta and Sr for both ores and granites.The W element of granite is 1.1-7.6 times than that of the similar rocks in the same region,providing a wealthy material basis for deposit-forming.Characteristics of rare earth elements of ores and granites show obvious similarities,taking on the features of high total rare earths,relatively obvious Eu negative anomalies,not obvious Ce anomalies and the right-declining of rare earth elements distribution patterns,which further suggests that scheelite mineralization and magmatic activity have a close genetic relationship.