西藏多龙矿集区美日切错组火山岩成因及与铁格隆南铜（金）矿床成矿的关系

发布时间：2018-04-17 21:32

  本文选题：火山岩成因 + 成矿地质背景　； 参考：《成都理工大学》2015年硕士论文

【摘要】：多龙矿集区铁格隆南铜(金)矿床的勘查与突破是近年来班公湖-怒江成矿带内取得的最令人瞩目的找矿勘查成果,矿床类型的厘定对区域找矿工作奠定了重要的理论和勘查评价研究基础,加强对该矿床的成矿地质背景研究,无疑对区域找矿及勘查突破具有重要的指导意义。本文以多龙矿集区美日切错组火山岩为研究对象,通过详细野外地质调查、岩石学、同位素年代学、岩石地球化学及同位素地球化学等研究工作,探讨了火山岩成岩与铁格隆南矿床成矿的关系。LA-ICP-MS锆石U-Pb年代学研究表明,铁格隆南矿区安山岩成岩年龄为(110.01±0.68)Ma(MSWD=2.3),形成于早白垩世。通过对矿区安山岩顶底界面的数学模拟,认为矿区地表的火山喷发类型为中心-裂隙组合喷发。进一步详细的岩石学及岩石地球化学研究表明,美日切错组火山岩以发育一套玄武岩-玄武质安山岩-安山岩-英安岩的岩石组合类型,具有由不成熟弧向成熟弧过渡,并向成熟大陆边缘弧转化的特征。岩石地球化学特征限定其具有岛弧火山岩的岩石地球化学特征,岩浆源区来自于Ⅱ型富集地幔(EMⅡ),是俯冲沉积物熔体交代地幔源区部分熔融的产物,在岩浆上升过程中混染了上地壳物质,产出构造背景限定于安第斯型活动大陆边缘,表明其属一套典型的大陆边缘型岛弧火山岩,形成于早白垩世班公湖-怒江洋盆向北俯冲的动力学背景下,是该动力学背景下诱发的岩浆产物?铁格隆南矿区安山岩包体的岩石学研究表明,其岩性为主要产出于造山环境的辉石安山岩,产出位置与铁格隆南矿体的空间位置之间的关系更加紧密。含包体安山岩的分布范围可能指示了铁格隆南矿体的分布位置,是该矿区内重要的近矿找矿标志之一。综上所述,铁格隆南矿区美日切错组火山岩的形成时间应晚于铁格隆南矿床的形成时间,在矿体形成后发生侵蚀作用的初期即覆盖于矿体之上,是该矿床得以完好保存的重要条件之一。同时美日切错组火山岩的研究为铁格隆南矿床的成矿地质背景研究提供了更多的证据支持。
[Abstract]:The exploration and breakthrough of the Tiegelongnan copper (gold) deposit in the Dulong ore concentration area is the most remarkable result of prospecting and exploration in recent years in the Bangong Lake-Nujiang metallogenic belt.The determination of ore deposit types has laid an important theoretical foundation for regional prospecting and exploration and evaluation, and strengthening the study of the metallogenic geological background of the deposit is undoubtedly of great significance for regional prospecting and exploration breakthroughs.Based on the detailed field geological survey, petrology, isotopic chronology, geochemistry and isotopic geochemistry, the volcanic rocks of the Meijichijiao formation in the Dulong ore concentration area are studied in this paper.The relationship between volcanic diagenesis and mineralization of Tiegelongnan deposit. LA-ICP-MS zircon U-Pb chronology study shows that the diagenetic age of andesite in Tiegelongnan ore area is about 110.01 卤0.68 MaMSWDU 2.3, which was formed in early Cretaceous.Through the mathematical simulation of the roof and bottom interface of the andesite in the mining area, it is considered that the type of volcanic eruption on the surface of the mining area is the center-fissure combination eruption.Further detailed petrological and petrogeochemical studies indicate that the volcanic rocks of the Mei-Japan Chijiao formation have developed a set of rock assemblages of basalt, Black Tortoise andesite, andesite andesite andesite, with a transition from immature arc to mature arc.And the characteristics of the arc transformation to the mature continental margin.The petrogeochemical characteristics limit its petrogeochemical characteristics of island arc volcanic rocks. The magma source region is derived from type 鈪，

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