东天山企鹅山群火山岩成因及成矿示踪

发布时间：2018-02-14 08:40

本文关键词： 企鹅山群岩石地球化学洋脊俯冲成矿示踪　出处：《新疆大学》2015年硕士论文　论文类型：学位论文

【摘要】：新疆东天山企鹅山群火山岩为一套岛弧玄武岩、安山岩、富Nb玄武岩、高镁安山岩、埃达克岩组合。玄武岩主量元素显示出富铝、高钛、低碱的地球化学特征,具有富集大离子亲石元素和轻稀土元素,相对亏损重稀土元素的特征,富Nb玄武岩具有Nb、Ta正异常的特征;高镁安山岩具有高镁、高钠、低钾、富集轻稀土元素的特征;埃达克岩具有高Sr、低Yb的特征。该组玄武岩εNd(t)=5.61~6.99,显示源区主要为地幔成分,同时受到地壳物质混染。埃达克岩具有相对偏高的εNd(t)、较年轻的Nd同位素模式年龄,为初生洋壳部分熔融而成。高镁安山岩为板片熔体与地幔橄榄岩混合的产物,且熔体中含有更多的地幔组分。其岩石组合特征、地球化学特征、源区特征、岩浆演化特征及其构造背景,表明该组火山岩是一套与洋脊俯冲有关的岩浆活动的产物。洋脊俯冲对于东天山觉罗塔格一带斑岩型铜金矿具有重要的意义,同时对新疆北部斑岩型铜金矿具有重要的勘查意义。
[Abstract]:The volcanic rocks of the Penguin Mountain group in eastern Tianshan, Xinjiang are a set of island arc basalt, andesite, NB rich basalt, high mafic andesite and adakite assemblage. The major elements of basalts show geochemical characteristics of rich in aluminum, high titanium and low alkalinity. It is characterized by the enrichment of large ion lithophile elements and light rare earth elements, the relative depletion of heavy rare earth elements, the positive anomaly of NB rich basalt and the characteristics of high magnesium, high sodium, low potassium and rich light rare earth elements. The adakite is characterized by high Sr and low Yb. The basalts in this group are 5.61 ~ 6.99, indicating that the source region is mainly mantle composition and mixed by crustal materials. The adakite has relatively high 蔚 Ndndnthe, younger ND isotopic model age. High mafic andesite is the product of lamellar melt and mantle peridotite, and the melt contains more mantle components. The characteristics of magmatic evolution and its tectonic setting indicate that the volcanic rocks in this group are the product of a set of magmatic activities related to the subduction of the oceanic ridge, which is of great significance to the porphyry copper-gold deposits in the eastern Tianshan Jolotag area. At the same time, it is of great significance for the exploration of porphyry copper and gold deposits in northern Xinjiang.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P588.14;P618.41;P618.51

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