【作者】 肖惠良；

【导师】 王鹤年； 周济元；

【作者基本信息】 南京大学 ， 地球化学， 2003， 博士

【摘要】 新疆多拉纳萨依金矿床位于阿尔泰西南、西伯利亚板块西南缘额尔齐斯构造—岩浆成矿域西南部，额尔齐斯挤压带西北段，玛尔卡库里大断裂西侧。该区早古生代为西伯利亚板块南部的大陆边缘裂陷盆地，加里东期形成褶皱带后，晚古生代早期又于南、北两侧开裂、扩张、发育上叠式的裂谷带，在海西中、晚期演化为造山带。矿体以含金钠长岩脉（糜棱岩化钠长岩、钠长石-石英脉）、矿化千枚岩、糜棱岩赋存于韧性剪切带中，金矿物以大量碲化物、碲金矿、碲金银矿等为特征。多拉纳萨依金矿床是韧性剪切带中与钠长石花岗岩脉群有关的碲化物型金矿床。多拉纳萨依金矿区发育了一套古生代浅变质陆源碎屑岩和浅海相碳酸盐沉积建造，岩性为灰绿色片理化粉砂岩、碳质粉砂岩，千枚岩化粉砂岩夹砂质灰岩和薄层灰岩。在海西期，矿区遭受了拉张-挤压-拉张的地质作用，经历了大陆边缘拉张裂谷-挤压造山-局部拉张的演化历史，并伴随有相应的岩浆及成矿作用。矿区构造变形强烈，碎裂岩化、糜棱岩化、劈理、片理化带十分发育。近南北向、反“S”形的三条控岩（脉）、控矿的层间走滑-拆离破碎-韧性剪切带、海西中晚期挤压作用形成的多拉纳萨依-阿克萨依向斜、布托别山背斜同斜紧闭倾竖褶皱和海西晚期挤压作用形成的北北东向脆—韧性剪切带构成了多拉纳萨依金矿田基本构造格架。矿区钠长岩和花岗闪长岩是两期不同来源、不同成因的花岗岩。钠长石花岗岩形成于海西早期拉张环境，是壳幔圈层滑动，致使热流值升高，导致下地壳和上地幔重熔形成的以幔源为主的花岗岩，Rb-Sr等时线年龄为352.5±40Ma，单颗粒锆石Pb-Pb表面直接蒸发年龄为371±22Ma，造岩矿物以钠长石、石英、白云母为主，SiO₂为54％—73％，高Al₂O₃为15.32％—17.17％，富Na₂O（3.42％—7.97％），贫K₂O（0.83％—3.42％）；Al₂O₃／（Na₂O+K₂O+CaO）＞1.2，Na₂O／K₂O为1.14—5.24，∑REE为50.69×10^-6-111.39×10_-6，LREE／HREE为4.82-16.58；δEu0.89-1.42，δCe0.81-1.0，球粒陨石标准化曲线为右倾型；(⁸⁷Sr／⁸⁶Sr)_i初始值为0.7043。其中含大量挥发组分CO₂、H₂O、S、Te、SiO₂、Cl、Na₂O、K₂O和Au等元素，平均含金24.0×10^-9，是多拉纳萨依金矿区主要含金源岩。花岗闪长岩形成于海西中期挤压环境，是上地幔分异岩浆上升熔融下地壳物质形成的同熔性花岗岩。Rb-Sr等时年龄为297±11Ma，U-Pb法求得和谐年龄289±5Ma，平均含金3.28×10^-9；造岩矿物以斜长石、石英、角闪石为主，岩石化学成分与钠长岩相似，高Al₂O₃，富Na₂O，贫K₂O，Na₂O／K₂O为1.76-4.72：∑REE为134.74×10^-6-183.19×10^-6，LREE／HREE为2.52-2.87；稀土分馏强烈，且为轻稀土富集型，δEu0.73-0.85，δCe0.91-0.99，球粒陨石标准化曲线为右倾平缓型；(⁸⁷Sr／⁸⁶Sr)_i初始值为0.7073。花岗闪长岩及其中辉石闪长岩析离体、石英闪长玢岩、碱长花岗岩构成完整的岩浆演化系列，为多拉纳萨依金矿床成矿提供了大量热流体和部分成矿物质。多拉纳萨依金矿区金矿体主要为糜棱岩化钠长岩脉、蚀变钠长岩脉、矿化砂岩、矿化千枚岩，呈分枝复合的脉状、透镜状，赋矿围岩以钠长岩为主，少量变质砂岩。金属矿物主要为黄铁矿、少量自然金、碲金矿、磁黄铁矿、黄铜矿、方铅矿、闪锌矿、黝铜矿、辉铋矿、碲铅矿、碲铋矿、磁铁矿等；脉石矿物主要有钠长石、石英、白云母-绢云母、绿泥石，少量碳酸盐、磷灰石、金红石等。围岩蚀变主要有钠长石化、白云母—绢云母化、黄铁矿化、硅化，次有矽卡岩化、碳酸盐化，表生作用引起粘土化、褐铁矿化、石膏化等。成矿作用分为五个成矿阶段：成矿作用主要分四个成矿阶段：钠长石花岗岩成矿阶段、构造动力变质成矿阶段、岩浆热液成矿阶段和岩浆期后热液叠加成矿阶段。成矿年龄区间为269.0Ma-371.2Ma。金矿物主要为自然金和碲金矿系列，自然金成色高，大多在950以上，含Ag、Hg、Bi、Te、Fe等微量元素，赋存状态主要有包体金、裂隙金和晶隙金；碲金矿系列金矿物主要分布在石英脉中，有碲金矿、针碲金矿、铋叶碲金矿、亮碲金矿、碲铅铜金矿等。矿石中Au与Bi、Li、Ba、As、Zn、Be、Mo呈正相关，与Cu、W呈负相关，其中与Bi最密切，相关系数为0.498。聚类分析表明矿石微量元素组合主要有Cr-Ni-Co-Cu、Rb-Ba-Be-Li、As-Pb-Ag-Zn-Sb、Au-Bi。多拉纳萨依金矿床为中—低温浅成热液矿床。该金矿床成矿物理化学条件为：成矿温度：160℃—315℃；成矿压力：212.8×10⁵Pa—648.5×10⁵Pa，形成深度为0.53-1.6km；流体盐度：气液包裹体为2.75-10.86NaCl％Wt；含子晶包裹体为35.57-37.22NaCl％Wt；氧逸度(f_O2)：10^-44.3—10^-31.8；硫逸度(f_S2)：为10^16.56—10^-10.91；碲逸度(f_Te2)：为10^-13.39—10^-4.24；pH：3.89—5.55；Eh：-0.58 eV—-0.72eV。多拉纳萨依金矿床成矿流体是主要由岩浆水、变质水、大气降水、地下水及岩石建造水、地层封存水组成的混合水。成矿流体中金的存在、迁移形式主要为HAu（HS）₂⁰、Au（HS）₂^-、Au（HTe）₂^-、Au（Te₂）^-、Au₂（Te₂）⁰、Au（Te₂）₂^3-、Au（Cl₂）^-；自然金和碲化物系列金矿物沉淀的主要机制为流体冷却作用、流体沸腾去气作用、糜棱岩化作用阶段的构造压剪作用和流体混合作用。该矿床是一个钠长石花岗岩脉群—韧性剪切—后期岩浆热液叠加、富集成矿“三位一体”多期次、多阶段、复成因形成的中—大型金矿床。其成因模式如下：早—中泥盆世，本区处于拉张期，矿区堆积了托克萨雷组陆源碎屑岩和浅海相碳酸盐岩建造，晚泥盆世—石炭纪，受西伯利亚板块向西南推挤，洋壳板块向北俯冲、对接，泥盆纪沉积盆地褶皱造山，矿区受左旋剪切，形成东西向挤压、南北向拉张的构造应力场作用，形成一系列南北向紧闭同斜褶皱；浅部伴生脆—韧性断裂，深部则强烈韧性剪切和圈层滑动，致使热流值骤然升高，导致俯冲洋壳的物质重熔，形成富含大量成矿物质组分CO₂、H₂O、Cl、S、Te、和Au等元素的长英质—钠长石花岗岩浆沿韧性剪切带和走滑断裂上升，并充填于韧性剪切带和走滑断裂，形成含金较高的钠长石花岗岩脉。随着区域构造应力作用，矿区地层发生褶皱，刚性碳酸盐岩与塑性泥质粉砂岩之间发生韧性剪切，钠长石花岗岩、泥质粉砂岩等发生糜棱岩化，钠长石花岗岩受韧性剪切形成糜棱岩化钠长岩，泥质粉砂岩等则变成片岩、千枚岩，与此同时，钠长石花岗岩中的金进一步活化、迁移、沉淀、富集形成金矿脉。石炭纪末准噶尔海盆封闭，哈萨克斯坦板块和西伯利亚板块拼合，区域构造作用力方向发生偏斜，矿区受右旋剪切作用，应力场转为SN向挤压、EW向拉张，在矿区形成一系列近SN向张裂隙，深部壳、幔层圈滑动致热，导致部分熔融，形成花岗岩类（花岗闪长岩）岩浆及其热液侵入，岩体周围地层发生大规模角岩化，促使金矿化叠加富集。岩浆活动晚期，一些NE向碱性岩脉上升，侵入在别列孜克花岗岩中，再次引起金的富集。更多还原

【Abstract】 The Duolanasayi gold deposit, in 180km SW of Altay city in Xinjiang, is a middle-largescale telluride-type gold deposit controlled by the the brittle-ductile shear, albite-granite dykes,and post-stage magma solution of the rift valley dragging of the continental margin in earlyPalaeozoic Era. After Caledonian folding, this area developed open fissure and grew into rift inboth side of south and north in early stage of late Palaeozoic Era. Developing orogen formed inmiddle-late Variscian. The ore bodies, which are situated in the opposite "S" shape in the SNstrike, are present as the albitite veins （mylonitic albitite and mineralized albite-granite） andmineralized phyllite. There are lots of tellurides such as calaverite, petzite, sylvanite.It was developed that the slight metamorphous terrignous clastic rock, shallow sea faciescarbonatite formation of the Jiangjuleke group and the Tuokesalei group of the early-middleDevonian system in Duolanasayi gold deposit district, which consists of grey and green schistosesiltstone, carbonaceous siltstone, phyllitization siltstone and sandy limestone, flag limestone.Being dragged and pressed, the gold deposit district evolved from the rife valley dragging of thecontinental margin to compression and mountain making to local dragging taken place and fit inwith magmatism and mineralization in Variscian. With lots of clastation, mylonitic, schistositycleavage, the rock of gold deposit district are great deformation. The basic structure pattern of thegold deposit district consists of three interformational sliding fault-pulled and fractured-brittle-ductile shear zones, which opposite "S" shape in the SN strike, are present as the ore veinsor dyke, two predominantly isoclinal plunging folds of the Duolanasayi-Akesayi syncline andButuobieshan anticline in middle-later Variscian, and the NNE strike cleavages in late Variscian.There are two stages granite with origin and genesis. One is albite-granite dykes, the other isgranodiorite.The albite-granite dykes, which was the remeiting of the mantle and underthrust ocean crust,is the mantle-type granite in the rift valley dragging of the continental margin. It is bound up withgold mineralization with gold content of 97.1×10^-9, and is major ore-bearing formation inDuolanasayi gold deposit. The rock forming principal mineral are albite, quartz, muscovite. Thepetrochemistry show middle SiO₂（54-73%）, high Al₂O₃（15.32-17.17%）, rich Na₂O（3.42-7.97%）and poor K₂O（0.83-3.42%）. The characteristics of rare elements show thatΣREE are 50.69×10^-6-111.39×10^-6, LREE/FIREE are 4.82-16.58, （La/Yb）_N are 5.70-37.34;δEu are 0.89-1.42,δCe are 0.81-1.0; The primitive rate of(⁸⁷Sr/⁸⁶Sr)_i is 0.7043.The granodiorite derived from the syntactic magma of the upper-mantle basic magma andlower-crust materials of the plate subduction’s island arc in orogenic zone. The rock formingprincipal mineral are anorthose, quartz, diastatite. The petrochemistry show that features of Al₂O₃,rich Na₂O and poor K₂O.ΣREE are 134.74×10^-6-183.19×10^-6, LREE/HREE are 2.52-2.87,（La/Yb）_N are 3.98-5.68:δEu are 0.73-0.85,δCe are 0.91-0.99;The primitive rate of(⁸⁷Sr/⁸⁶Sr)_iis 0.7073. The granodiorite, with xenolith of angite diorite, quartz diorite porphyry and alkalicfeldspar granite in granodiorite batholith, consists of a magma evolution series, and providedenormous hot energy and some ore materials.The three ore types in the Duolanasayi gold deposit are pyrite-gold-altered rock,gold-albite-quartz and ferrohydrite-gold-quartz. The ore minerals include pyrite, native gold,calaverite, pyrrhotite, chalcopyrite, galena, sphaterite scheelite, and the minority of chlcocite, covellite, bilbinskite and minium. The gangue minerals include quartz, calcite and carbonaceousminerals. The wall rock alteration associated with gold mineralization comprises of albitization,muscovitization -sericitization, pyritization and silicification, albite granite, mylonitic albititealbite-quartz, pyrite -muscovite-sericite-quartz and quartz-calcite are five main mineralizingphases. The metallogenetic epoch is 269.0Ma-371.2Ma.Gold minerals in the Duolanasayi deposit are dominated by native gold and gold-bearingtellurides. There are three gold-bearing types of native gold: in inclusion, in crack of minerals andin crack of minerals crystal. The percentage of Au in native gold is high （＞950）, and there are alittte of Ag, Hg, Bi, Te, Fe etc. The gold minerals of the gold-bearing tellurides are calaverite,petzite, sylvanite, montbrayite and so on, are characteristic in the gold deposit.According to elements correlating analyses, Au in positive relationship with Bi, Li, Ba, As,Zn, Be, Mo and negative Cu, W. There are four trace elements compound of Cr-Ni-Co-Cu,Rb-Ba-Be-Li, As-Pb-Ag-Zn-Sb and Au-Bi in gold ore.Fluid inclusions studies indicate that the homogenization temperatures rang from 160℃to315℃with the peak values of 220℃-300℃. Mineralization pressures is from 21.0×10 Mpa to64.5 Mpa. The ore fluid inclusion contains Ca²⁺, K⁺, Na⁺, Mg²⁺; HCO₃^-, SO₄^2-, HS^-, F^-, Cl^- andAu(max is 5.3×10^-6). Salinities of fluid rang from 2.75-10.86NaCl%Wt in gas-solution inclusionsand 35.57-37.22NaCl%Wt in halite-bearing multi-phase inclusions, f_O2=10^-44.3-10^-31.8, f_S2=10^-16.56-10^-10.91, f_Te2=10^-13.39-10^-4.49, pH=3.89-5.55; Eh=-0.58--0.72eV. The mineralizing fluid is aH₂O-CO₂ system. Sulfur, hydrogen, oxygen and strontium isotopic compositions (δ³⁴S=-2.46‰--7.02‰,δ¹⁸O_H2O=1.65‰-12.4‰,δD=-132.2‰--51.8‰, The primitive rate of (⁸⁷Sr/⁸⁶Sr)_i=0.7043-0.7073) suggest the ore-forming fluid of the Duolanasayi gold deposit was a kind ofmixed hydrothermal solution mainly composed of magmatic water, metamorphic water, meteroricwater and formation water in rocks. The magmatic water in early mineralization is mantle fluid.HAu （HS）₂⁰、Au（HS）₂^-、Au（HTe）₂^-、Au（Te₂）^-、Au₂（Te₂）⁰、Au（Te₂）₂^3- and [AuCl₂]^- arelikely be the principal gold complexes in ore-bearing fluid. Four major types of precipitation ofgold are the action of boiling and exhaust, pressing and shearing in mylonitization stage,condensation and solution mixing in mineralization.Based on the above descriptions, the mineralization pattern of this gold deposit as follow:As a result of the tensile stress of rife in Duolanasayi gold deposit district, the albitite-granitemagma, which is the remelting material of lower-crust and upper-mantle, emergenced along faultand emplacement in the SN strike tension crack of the Tuokesalei group sedimentary formation inearly Variscian.In middle Variscian, the gold deposit district was pressed, as a result, the albitite-granite dykeand the rock of strata were folded and mylonitized. Meanwhile, with the brittle-ductile shear andthe granodiorite emergenced, the gold was activated, migrated, concentrated by the mineralizationof the brittle-ductile shear and post-magma hot fluid activation.The alkalic feldspar granite dyke, with the hot energy and ore-bearing hot fluid emergencedalong brittle-ductile shear zone in the NNE and NE strike, the gold was superimposed and enrichin later Variscian.更多还原