ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    青海治多多彩地区火山岩岩石特征

    Characteristics of Volcanic Rocks and Analysis on the Prospecting Potentiality in Duocai Region, Zhiduo County, Qinghai Province

    • 摘要: 多彩地区处于西金乌兰-义敦晚三叠世岛弧带的东段,成矿区带位于三江成矿带的北西段,区内已发现了尕龙格玛铜多金属矿床和拉迪欧玛铜矿点。重点分析了与该区成矿关系密切的火山岩的岩石特征,初步恢复了该区火山岩的喷发环境和火山机构,并探讨了火山活动与成矿的关系。研究表明,本区火山岩主要为英安岩及英安质火山碎屑岩,其次为安山岩、安山质火山碎屑岩。火山岩微量元素具有富集亲石元素Rb、Sr、Th及亲铁元素Co、Ni,亲Cu元素Zr与参照值相近,V、Ba元素的含量高于地壳的丰度值,Sc、Cr等元素亏损的特征。中-酸性火山岩稀土总量较高,稀土配分曲线上普遍出现Eu负异常,总体特征与造山带火山岩相似,火山岩相为溢流相。本区海相火山喷发发生在浅海地带,火山岩构造环境总体属于岛弧环境。成矿作用主要与古火山机构和后期动力变质作用有关。

       

      Abstract: Duocai region lies in the east of Late Triassic Xijinwulan-Yidun island arc zone,belonging to the northwest of Sanjiang Metallogenic Belt.Galonggema copper-polymetallic deposit and Ladiouma copper mineralized spot have been discovered for many years in this belt.This paper focused on the characteristics of volcanic rocks which close to the mineralization in the area,restored volcanic apparatus and volcanic eruption environment,and discussed the relationship between volcanic activity and mineralization.Studies have shown that the volcanic rocks in this area are mainly dacite and dacitic pyroclastic rocks,followed by andesite,andesitic pyroclastic rocks.Trace elements of volcanic rocks enriched in lithophile elements Rb,Sr,Th and siderophile elements Co,Ni.Chalcophile elements and Zr is similar to the reference value,V and Ba contents are higher than the element abundance of the crust,and Sc,Cr are depleted.∑REE of intermediate-acidic volcanic rocks are higher,and general characteristics are similar with volcanic rocks of orogenic belt with negative Eu anomalies on the REE patterns.Volcanic phase of the overflow phase.Volcanic eruption was happen in shallow marine zone with structure environment of volcanic belongs to island-arc environment.Mineralization mainly related to ancient volcanic apparatus and the late dynamic metamorphism.

       

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