含金屬沉積物是海底熱液活動(dòng)的產(chǎn)物之一,由熱液成因的含金屬礦物與遠(yuǎn)洋沉積物混合沉積而成。由于含金屬沉積物攜帶了熱液的源區(qū)和熱液循環(huán)的動(dòng)力學(xué)信息,對(duì)其礦物學(xué)和地球化學(xué)研究對(duì)于重建熱液活動(dòng)的歷史、位置、強(qiáng)度和演化至關(guān)重要。對(duì)遠(yuǎn)軸深海沉積物中熱液成因礦物的識(shí)別能為隱伏熱液礦床的勘探提供有效手段�？査共窦�(簡(jiǎn)稱卡脊)位于西北印度洋,是印度洋板塊與索馬里板塊的構(gòu)造邊界。卡脊的擴(kuò)張速率為22～32 mm/yr,屬于慢速擴(kuò)張洋脊。與同為慢速擴(kuò)張洋脊的大西洋中脊相比,卡脊的研究程度非常有限,一直以來(lái)都沒(méi)有發(fā)現(xiàn)熱液活動(dòng)和多金屬硫化物。2013年,中國(guó)在卡脊中段一處新火山脊的西北坡發(fā)現(xiàn)了以玄武巖為圍巖的臥蠶熱液區(qū)。初步的調(diào)查顯示,該熱液區(qū)包含兩處熱液點(diǎn),臥蠶-1#和臥蠶-2#,其中,臥蠶-1#水深2970～2990m,目前仍存在高溫?zé)嵋夯顒?dòng),而非活動(dòng)的臥蠶-2#位于臥蠶-1#西北方向～2.7km處,水深3100m,主要產(chǎn)出坍塌的硫化物煙囪。一般來(lái)講,在海底熱液循環(huán)中,熱液上升系統(tǒng)的動(dòng)態(tài)活動(dòng)能夠直接觀察得到,熱液補(bǔ)給系統(tǒng)卻不可見(jiàn)。由于針對(duì)臥蠶熱液區(qū)獲取的信息還十分有限,對(duì)含金屬沉積物的地球化學(xué)研究不僅能夠...

【文章頁(yè)數(shù)】：123 頁(yè)

【學(xué)位級(jí)別】：博士

【文章目錄】：
Acknowledgement
中文摘要
ABSTRACT
1 Introduction
    1.1 Seafloor hydrothermal systems
        1.1.1 Active hydrothermal vent systems
        1.1.2 Inactive hydrothermal vent systems
    1.2 Products of seafloor hydrothermal circulations
        1.2.1 Massive sulfides
        1.2.2 Hydrothermal mounds
        1.2.3 Chimneys
        1.2.4 Hydrothermal breccia
        1.2.5 Ochreous and Gossan deposits
        1.2.6 Fe-oxyhydroxides and silica deposits
        1.2.7 Metalliferous sediments
    1.3 Geological settings of Carlsberg Ridge
    1.4 Geological characteristics of Wocan hydrothermal field
    1.5 Research objectives and Thesis content
2 Materials and methods
    2.1 Wet-sieve analysis
    2.2 Mineral abundance and chemistry
    2.3 Bulk sediment geochemistry and mineralogy
    2.4 Sulfur isotope analysis
    2.5 XRF Core Scanning and AMS ¹⁴C dating on sediment core
3 Mineralogical and geochemical signatures of metalliferous sediments in Wocan-1 andWocan-2 hydrothermal sites:Implication for the dynamics of hydrothermal circulationand post-depositional process
    3.1 Mineralogy, morphology, and abundance of sulfide and non-sulfide grains
    3.2 Bulk sediment geochemistry
    3.3 Mineral chemistry of sulfide separates
    3.4 Sulfur isotopes
    3.5 The effect of primary and post-depositional changes, evidence from grain texture,bulk chemical compositions and mineral chemistry
    3.6 The contributions of hydrothermal fluid, evidence from S isotope values
    3.7 Summary
4 Geochemical investigations of Fe-Si-Mn oxyhydroxides deposits in Wocan-1 andWocan-2 hydrothermal sites: Constraints on their origin in relation to the hydrothermalprocess
    4.1 Bulk sediment mineralogy
    4.2 Morphology and relative abundance of Fe-oxyhydroxide separates
    4.3 Origin and formation process of Wocan-1 Fe-oxyhydroxides and their associationwith the hydrothermal process
    4.4 Origin and formation process of Wocan-2 Fe-oxyhydroxides and their associationwith the hydrothermal process
    4.5 Origin and formation process of oxyhydroxide separates from the Ridge flanksediment
    4.6 Summary
5 A mineralogical and geochemical study of bulk sediments core from 4°07'N/69°20'E,Indian Ocean:Implication for the transportation of hydrothermal particles from theCarlsberg Ridge
    5.1 Mineralogical and chemical investigations
    5.2 Age model and sedimentation rate
    5.3 Vertical and temporal changes in mineralogical variations
    5.4 Implications on the vertical and temporal changes in the mineralogical variations
    5.5 Summary
6 Conclusions and Future work
    6.1 Conclusions
    6.2 Future Research
References
Appendices
    Appendix 1: Bulk chemical composition (ICPMS data) of metalliferous sedimentsfrom WHF and Ridge flanks
    Appendix 2. EPMA data on chalcopyrite grain separate from Wocan-1 and Wocan-2hydrothermal site
    Appendix 3. EPMA data on pyrite grain separate from Wocan-1 and Wocan-2hydrothermal site
    Appendix 4. EPMA data on sphalerite grain separate from Wocan-1 and Wocan-2hydrothermal site
    Appendix 5. Analytical equipment and approach methodology
    Appendix 6. Authored works 1
    Appendix 7. Authored works 2
Biography



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