發(fā)布時間：2021-02-07 02:35

　　厄立特里亞中部的變質(zhì)火山-沉積組合和相關(guān)的花崗質(zhì)侵入體位于阿拉伯-努比亞地盾南部,主要由新元古代新生島弧的增生形成。本研究的主要目的是探討該地區(qū)火山巖和花崗巖的成因及構(gòu)造背景。研究區(qū)地表巖石類型以含變質(zhì)沉積單元的鎂鐵質(zhì)-長英質(zhì)變質(zhì)火山巖為主。這些變質(zhì)火山巖主微量元素組成變化較大,其中SiO₂（41.63-78.4 wt.%）、Al₂O₃（8.51-23.41 wt.%）、MgO（0.05-13.98 wt.%）、Fe₂O₃（3.11-15 wt.%）、K₂O（0.01-2.59 wt.%）、Cr（2.83-834 ppm）、Ni（1.63-244 ppm）、Zr（16.4-128 ppm）,巖石主微量元素含量具有線性特征,表明它們存在成因聯(lián)系,而含量的變化范圍較大可能是地殼同化和分離結(jié)晶導(dǎo)致。樣品稀土元素總量低（20-144 ppm）,配分模式平坦,具有輕微Eu負(fù)異常（Eu/Eu*=0.67-1.36）。微量元素蛛網(wǎng)圖顯示富集大離子親石元素（LILE,Ba... 

【文章來源】：中國地質(zhì)大學(xué)湖北省 211工程院校 教育部直屬院校

【文章頁數(shù)】：103 頁

【學(xué)位級別】：博士

【文章目錄】：
Resume of the Author
摘要
abstract
Chapter1 Introduction
    1.1 General Introduction
    1.2 Description of the study area
    1.3 Research objectives and significance
        1.3.1 Objectives of the research
        1.3.2 Significance of the research
Chapter2 Regional Geology
    2.1 Regional Geological setting
        2.1.1 Tectonic crustal evolution of ANS
        2.1.2 The Neoproterozoic geology of Eritrea
    2.2 Geological Setting of Central Eritrea
        2.2.1 Mafic/intermediate metavolcanic（MIV）unit
        2.2.2 Felsic metavolcanic（FMV）unit
        2.2.3 Metasedimentary unit
        2.2.4 Granitoid intrusive unit
    2.3 Structural geology and metamorphism
        2.3.1 Structures
        2.3.2 Metamorphism
Chapter3 Methodology
    3.1 Geological field investigation and sample collection and preparation
    3.2 In-situ LA-ICP-MS U-Pb zircon dating
    3.3 Whole-rock analyses by XRF and ICP-MS
    3.4 TIMS Sr-Rb-Pb isotopic analysis
Chapter4.Results
    4.1 Zircon U-Pb age of the Emba-Derho granodiorite
    4.2 Whole-rock major and trace elements
        4.2.1 Metavolcanic rocks
        4.2.2 The granitoid intrusion
    4.3 Whole-rock Sr-Nd-Pb isotopic compositions
        4.3.1 Isotopic compositions of metavolcanic rocks
        4.3.2 Isotopic composition of the granitoid rocks
    4.4 Evaluation of element mobility
Chapter5.Petrological classification,Geochronology and petrogenesis of the granitoid greenstone rocks
    5.1 Petrological classification of the metavolcanic rocks
    5.2 Petrological classification of the Emba-Derho granitoid
    5.3 Geochronology
        5.3.1 Emplacement age of the Emba-Derho granodiorite
        5.3.2 Metamorphism age of the metavolcanic rocks
    5.4 Petrogenesis of the metavolcanic rocks
        5.4.1 Magma mixing vs.Differentiation
        5.4.2 Nature of the mantle source
    5.5 Petrogenesis of the Emba-Derho pluton
Chapter6.Tectonic Setting
    6.1 Tectonic Affinities of the metavolcanic rocks
    6.2 Tectonic affinities of the granitoid rocks
Chapter7.Mineral potential of the greenstone belt of Eritrea
    7.1 Geological and structural control of mineralization in the greenstone belt of Eritrea
    7.2 The main mineralization type of Eritrea associated with the greenstone and associated granitoid rocks
        7.2.1 Gold and Silver deposit
        7.2.2 Base metal deposits
        7.2.3 Industrial minerals
        7.2.4 Construction materials
    7.3 Implication for Exploration
Chapter8.Conclusions and Recommendations
    8.1 Conclusions
    8.2.Recommendations
Acknowledgement
References



本文編號：3021500