【作者】 陈广俊；

【导师】 迟效国； 孙丰月；

【作者基本信息】 吉林大学 ， 地球化学， 2014， 博士

【摘要】 沟里地区地处东昆仑造山带东段，近年来相继发现了多处金矿床。论文运用现代成矿理论，结合东昆仑造山带成矿动力学演化，剖析典型矿床的成矿构造背景、地质特征、成矿流体、成矿物质来源，探讨矿床的成因，建立成矿系列和成矿模式，开展金矿成（找）矿潜力评价。提出了东昆仑地区昆中和昆南带存在金的上地幔源区认识。东昆仑地区前寒武纪多次玄武质岩浆活动过程中，因岩石圈地幔的小比例熔融使形成的硅酸盐熔体可能在源区产生硫过饱和而发生硫化物熔体和硅酸盐熔体在源区熔离，因硫化物比重远大于硅酸盐熔体而滞留在上地幔。同时，因金等其他金属在硫化物中的分配系数比在硅酸盐熔体分配系数可高达4个数量级，因此金等多金属随硫化物一起滞留岩石圈上地幔，形成东昆仑地区金的上地幔源区。上地幔硫化物中的金比硅酸盐中的金易活化，容易被幔源C-H-O流体携带上升到地壳参与成矿。对典型矿床进行剖析，探讨了矿床成因。硫、铅、氢、氧同位素研究表明，成矿流体具有幔源特征，成矿物质主要来自上地幔。煌斑岩和金矿都属于幔源C-H-O流体分异演化过程中不同阶段的产物，煌斑岩中金的含量高是幔源流体从上地幔带来金的重要证据，认为东昆仑地区有幔源金参与了成矿。通过综合分析论证，达里吉格塘金矿床为斑岩型金矿床。矿床围岩蚀变发育，以大面积面型蚀变矿化为特征且具有分带性，蚀变主要为绢英岩化（似千枚岩化）、泥化和青磐岩化；矿石构造特征表现为细脉浸染状、角砾状构造等；流体包裹体研究显示成矿流体为低盐度和低密度流体；激光拉曼光谱分析流体包裹体气相成分普遍含CO2、CH4，成矿流体为CH4-CO2-H2O-NaCl体系，显示了幔源流体特征；石英绢云母化带的形成温度为147.6~435.7℃，峰值为260~320℃。这是整个东昆仑地区首次确定出的斑岩型金矿床。通过综合分析，坑得弄舍金多金属矿床为浅成低温热液矿床，并非前人认为的热水喷流成因。该矿床围岩蚀变主要有重晶石化、硅化、碳酸盐化、白云石化、绿泥石化等，表现出以低温为主的蚀变矿物组合特征，重晶石并非前人认为的热水喷流成因；流体包裹体均一温度在101-190℃之间，峰值主要集中于120-160℃之间，矿床受伸展构造体制控制。建立了沟里地区及外围金矿床成矿系列：“东昆仑沟里地区印支期金矿成矿系列”，并分为斑岩型成矿亚系列、造山型成矿亚系列和浅成低温热液型矿床成矿亚系列三个成矿亚系列，3个矿床式，即达里吉格塘式、果洛龙洼式与坑得弄舍式。建立了沟里地区及外围三种矿床类型成矿模式：1.造山型金矿成矿模式:(1)造山型金矿幔源C-H-O流体成矿模式：印支晚期，伸展作用引起岩石圈拆沉减薄，幔源C-H-O流体上涌至金的上地幔源区，萃取金等成矿物质运移至构造适合部位沉淀成矿，形成了本区造山型金矿床；（2）造山型金矿地壳不同深度的连续成矿模式：具有从中深成（阿斯哈金矿）→中成（按纳格）→中浅成（果洛龙洼）不同成矿深度连续成矿的特点，成矿深度分别为8.16~9.58km、6.88~8.86km和4.77~7.65km，成矿深度逐渐变浅，成矿流体均一温度从155℃到425℃范围内由低到高的变化。2.斑岩型金矿成矿模式：矿床形成于印支晚期由挤压体制向伸展体制转换的构造背景，幔源物质参与成矿。3.浅成低温热液型金多金属矿床成矿模式：矿床形成于印支晚期造山后伸展（？）的构造背景，幔源物质参与成矿。总结了矿化富集规律，并分析了矿床剥蚀保存条件，开展金矿成（找）矿潜力评价，认为果洛龙洼金矿床和坑得弄舍金多金属矿床具有很大的找矿潜力，而且根据横向对应规律预测坑得弄舍矿床两条主断裂带的另一条具有很大找矿潜力，应是下一步勘查工作重点。更多还原

【Abstract】 Gouli area is located in the eastern section of East Kunlun orogenic belt (EKOB). Inrecent years, many gold deposits have been found. This paper uses metallogenic theory,combined with mineralization dynamical evolution of EKOB, to analysis tectonic setting,geological characteristics, ore-forming fluid and mineral sources of typical deposits, todiscuss the genesis, to establish metallogenic series and a metallogenic mode, to carry outpotential evaluation of gold mineralization (prospecting).The paper proposes the existence of upper mantle gold in the middle and south beltsof East Kunlun area. During the repeatedly basaltic magmatism process of PrecambrianEast Kunlun, a small percentage melting of lithospheric mantle produced silicate meltforming sulfur supersaturation, and sulphide melt and silicate melt segregated in theregion. Because the sulphide density is much larger than silicate density, sulfides areresorted in the upper mantle. Meanwhile, due to distribution coefficient of gold and othermetals in the sulfide are four orders of magnitude than that in the silicate melt, gold andother metals together with sulphides are stranded on the lithospheric upper mantle,forming upper mantle gold of East Kunlun. Gold in sulfide of upper mantle is moreactivated than that in silicate, easy to be carried to the crust by mantle CHO fluid,involved in mineralization.To analyze the typical deposit, discuss the genesis. Sulfur, lead, hydrogen and oxygen isotope studies indicate that ore-forming fluids with characteristics of mantle, mineralmainly derived from the upper mantle. Lamprophyre and gold belong to the differentiationevolution product of mantle CHO fluid at different stages. High gold content oflamprophyre is important evidence of mantle fluids carrying gold derived from uppermantle. It is supposed that mantle gold involved in the mineralization in East Kunlunregion.Through comprehensive analysis and demonstration, Dalijigetang gold deposit isporphyry type. Wall-rock alterations are developed, with the characteristics of a large areasurface alteration and mineralization, and have zonation. Alterations are mainly phyllic(like phyllite), argillization and propylitization; ore structure characteristic manifestsveinlet, brecciated structure, etc.; fluid inclusion study displays low salinity and lowdensity of ore-forming fluids; composition of fluid inclusions generally containing CO2,CH4through laser Raman spectroscopy, that means ore-forming fluid isCH4-CO2-H2O-NaCl system, showing the characteristics of mantle fluid; formationtemperature of quartz sericite zone is from147.6℃to435.7℃, the peak is between260℃and320℃. It is the first time that it determines the porphyry gold deposits in thewhole East Kunlun area.Through comprehensive analysis, Kengdenongshe gold polymetallic deposits are ofepithermal deposits, not previously considered sedimentation-exhalation origin. The mainwall-rock alterations is barite, silicification, carbonation, dolomitization, chlorite, etc.,showing mainly low-temperature alteration mineral assemblages, barite not previouslyconsidered sedimentation-exhalation causes; fluid inclusion homogenization temperaturesis of101~190℃, mainly in the peak of120~160℃. The deposit is controlled byextensional tectonic regime.Establish gold metallogenic series of Gouli regional and peripheral area:" Indosiniangold mineralization series of Gouli area, East Kunlun ", and it is divided into threesub-series, porphyry-type, orogenic-type and epithermal-type metallogenic sub-series,three deposit styles, namely, Dalijigetang style, Guoluolongwa style and kengdenongshestyle. Establish metallogenic models of three deposit types of Gouli regional and peripheralarea:1. Orogenic gold metallogenic model:(1) Orogenic mantle CHO fluid metallogenicmodel: Late Indosinian, extension caused lithospheric delamination and thinning, mantleCHO fluid influxing into upper mantle gold, extraction of gold and other mineralstransporting to precipitate in a suitable structure site, forming orogenic gold deposits ofthe region;(2) Orogenic gold continuous metallogenic model at different depths in thecrust: It has the characteristics of continuous mineralization at different depths, frommeso-hypozonal (Asiha gold deposit) to meso-epizonal (Annage gold deposit) to epizonal(Guoluolongwa gold deposit), mineralization depth being8.16~9.58km,6.88~8.86kmand4.77~7.65km respectively, mineralization depth turning shallow, ore-forming fluidtemperature transition ranging from155℃to425℃.2. Porphyry gold metallogenic model: the formation of deposits in the transformationtectonic setting of Indosinian from extrusion to extension system, mantle-derivedsubstances involved in mineralization.3. Epithermal gold-polymetallic metallogenic model: the tectonic setting of thedeposit formed in post-orogenic stretch background of late Indosinian (?), mantle-derivedsubstances involved in mineralization.Summarizes the mineralization enrichment regularity, and analyzes the depositerosion and preservation conditions, to carry out gold mineralization (prospecting)potential evaluation. It is suggested that Guoluolongwa gold deposit and kengdenongshegold polymetallic deposits has great prospecting potential. And based on the lateralcorresponding theoretical, it predicts that another fault of the two main faults ofKengdenongshe deposits has prospecting potential, which should be the focus of next stepexploration work.更多还原