云南播卡金矿区钠长岩地球化学特征及其地质意义  

Geochemical characteristics and geological significance of the albitite in the Boka gold ore district,Yunnan Province

作　　者：肖晓牛[1,2] 余新明[1,2] 肖娥[1] 徐强[1] 林志奎 林迎洁 XIAO Xiaoniu;YU Xinming;XIAO E;XU Qiang;LIN Zhikui;LIN Yingjie(East China Mineral Exploration and Development Bureau for Nonferrous Metals, Nanjing 210007, Jiangsu, China;Fujian Jindong Mining Co., Ltd., Sanming 365101, Fujian, China)

机构地区：[1]江苏省有色金属华东地质勘查局,江苏南京210007 [2]福建金东矿业股份有限公司,福建三明365101

出　　处：《地质通报》2017年第8期1417-1427,共11页Geological Bulletin of China

基　　金：国家自然科学基金项目<云南播卡晚元古代岩浆作用与成矿效应:一种可能的IOCG模式>(批准号:41402077)

摘　　要：播卡金矿床位于滇中元古代铜金多金属成矿带之东川矿集区。重点报道了区内与成矿密切相关的钠长岩的岩相学、岩石地球化学及同位素特征。研究表明,播卡钠长岩的主要造岩矿物有钠长石、辉石、黑云母,主量元素特征显示其为富碱、高钠、偏铝质的碱性-过碱性岩石。岩石的稀土元素总量低,相对富集轻稀土元素,明显富集大离子亲石元素K、Rb、Nd及轻稀土元素La、Ce、Sm,相对亏损高场强元素Nb、Ta、U、Th等。岩石的I_(sr)值、ε_(Nd)(t)值显示,其可能为中元古代晚期会理—东川一带大陆裂谷岩浆作用的产物,来源于深部地幔,可能有部分陆壳物质的参与。The Boka gold deposit is located in the Dongchuan ore concentration area,and belongs to Yunnan Proterozoic copper polymetallic mineralization belt.This paper reports the petrography,geochemistry and isotope features of albitite that is closely related to mineralization.Studies show that the mineral compositions of albitite are albite,pyroxene,biotite,and the major element characteristics indicate a high Na,alkali-enriched,metaluminous,alkaline-peralkaline rock.This albitite is characterized by lowΣREE,strong enrichment of LILE(K,Rb,Nd)and LREE(La,Ce,Sm),and depletion of HFSE elements(Nb,Ta,U,Th).Based on Isr,εN(d t)isotopic geochemistry,it is suggested that Boka albitite was produced by magmatism of Middle Proterzoic continent rift in Huili-Dongchuan area,and it was derived from the deep mantle with the addition of some crustal materials in the magma source region.

关 键 词：播卡钠长岩 岩相学 地球化学 富集地幔 云南 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]