云南西畴县红石岩铅锌铜矿区绿岩地球化学特征及构造环境分析

Tectonic Environment Analysis and Geochemical Characteristics of the Greenstone of Hongshiyan Lead-zinc-copper Deposit in Xichou County,Yunnan Province

阐述了红石岩矿区成矿地质背景和矿区地质特征,并针对与矿区成矿关系密切的绿岩的岩石特征及主量元素、微量元素和稀土元素进行分析。结果表明,矿区的绿岩具有贫Al_2O_3、K_2O、Na_2O,而富TFeO、MgO、CaO的组成特征,Nb、Ta等元素亏损,大离子亲石元素(LILE)富集,微量元素原始地幔标准化蛛网图呈"大隆起"型,稀土元素呈现富轻稀土的右倾模式,轻重稀土分馏较明显。综合分析认为,矿区绿岩原岩为岛弧拉斑玄武岩,其形成的地质构造环境为俯冲背景的岛弧环境。

The author expounds the Hongshiyan metallogenic geological background and geological features,and analys the rock characteristics and major elements,trace elements and rare earth elements of the greenstone which is closed to the deposit metallogenic association.The results show that the greenstone of mining area has the characteristics of poor Al2O3,K2O and Na2O,and rich TFeO,MgO and CaO,loss the elements of Nb and Ta,enrichment of LTLE.The primitive mantle normalized trace element spidergram shows ＂ big rise＂ shape.The rare earth elements showed rich REE patterns of light rare earth,REE fractionation is obvious.Comprehensive analysis shows that the original rock of greenstone in the deposit is island arc tholeiite.The formation of geological environment of island arc tholeiite is in the subduction background in the island arc environment.