新疆北部主要金矿床的成矿地球化学特征

主要依据成矿作用方式,基本成矿特点及关键控矿标志等,将新疆北部的主要原生金矿新划分为７个矿床类型,分别是浅成低温热液型金矿、韧性剪切带蚀变岩型金矿、微细粒浸染型金矿、浅成岩－构造蚀变岩型金矿、变质热液型金矿、石英脉型金矿及铜、金伴生型矿床。通过分析比较各矿床类型典型金矿的ＲＥＥ分布型式、其矿石的微量元素含量与分布型式、硫与铅同位素组成及流体包裹体成分等资料,探讨了其成矿地球化学特征。     

川西—藏东地区金矿地质特征及遥感影象模式

川西－藏东地区的主要金矿类型有破碎蚀变岩型、与韧性剪切带有关的微细浸染型、黑矿型、斑岩型;结合各类型金矿产出的大地构造背景,以典型矿床为例,阐述了矿床地质特征;通过对各类型金矿的遥旬与分析,指出了各金矿类型的线,环遥感影象模式。     

剪切带含金石英脉型矿床的研究现状

近年来，国内外十分重视剪切带与金矿床关系的研究，提出了含金剪切带和剪切带型金矿床等新概念。何绍勋等（１９９２）按矿床特征将剪切带型金矿划分为“剪切带糜棱岩型金矿”和“剪切带脉型金矿”两种基本类型。含金石英脉型矿床是剪切带脉型金矿的主要类型。     

巴西阿尔塔·弗洛雷斯塔地区地质特征及金矿床类型

巴西马托格罗索州阿尔塔·弗洛雷斯塔(Alta Floresta)地区是亚马孙盆地西南部重要的金成矿省。为了满足中资矿业公司进行矿业投资和开发活动的需求,在实地考察和文献资料搜集的基础上,对该地区金矿地质特征和矿床类型进行了初步总结。该区主要的金矿类型有石英脉型、花岗斑岩型、红土型金矿等,其中石英脉型和红土型金矿为主要的金矿开发类型。区域构造对岩浆作用、金矿化作用和矿床类型等具有重要控制作用。总体来说,该地区具有多次金成矿活动,金成矿类型丰富,可作为中资矿业公司实施"走出去"战略的重要成矿区带。     

赣东北金矿成矿地质特征与找矿方向

赣东北地区金矿资源丰富,成矿地质背景优越,金矿床类型多样,有6类16型,其中主要工业类型为次火山斑岩型伴生金矿、韧性剪切带糜棱岩型金矿、剪切石英脉带蚀变岩型金矿和冲积型砂金矿。这四种工业类型中韧性剪切带糜棱岩型金矿和剪切石英脉带蚀变岩型金矿均有较好的勘查前景,尤以后者找矿潜力巨大。在叙述赣东北地区金矿成矿地质背景、金矿类型划分、金矿主要工业类型和典型金矿床实例的基础上,阐述了金矿成矿规律,提出了今后勘查的主攻矿床类型,找矿远景区,预测并指明了主要金矿类型的未来找矿潜力。为赣东北地区金矿的进一步勘查与开发,提供一些有益的参考和启示。     

东北非努比亚地盾金矿成矿地质特征与找矿标志

东北非金矿的矿床类型、成矿条件与努比亚地盾演化密切相关。努比亚地盾金矿类型,按成因可分为两大类:一类是与造山带有关的韧性剪切带金矿,即造山型金矿;另一类是弧-弧拼合过程中形成的火山成因块状硫化物金矿,即VMS型铜-金矿。受韧性剪切带控制的造山型金矿形成于闭合-碰撞造山阶段,与弧-弧碰撞缝合带展布方向一致的北东向韧性剪切带为造山型金矿的主要控矿构造,该类型矿床规模以中小型为主。沿韧性剪切带成带分布的火山成因块状硫化物(VMS型)金矿床形成于洋壳俯冲-岛弧的形成阶段,其形成环境为岛弧裂谷或弧后裂谷环境,矿床规模以大型为主,成群分布于5个矿集区内。本文总结了该地区造山带型和VMS型金矿的主要特征,并依此提出在该地区寻找此两种类型金矿的找矿标志。     

甘肃天水李子金矿床物质组分及金银赋存状态研究

甘肃天水李子金矿具有斑岩型和韧性剪切带型两种类型的金矿床。本文在详细野外工作的基础上,采用光薄片鉴定、人工重砂分析、化学成分分析、化学物相分析、电子探针波谱分析等技术方法,查明了矿床主要具有蚀变岩型和石英脉型两种金矿石类型,其中韧性剪切带型金矿矿石类型主要为石英脉型,斑岩型金矿矿石类型主要为斑岩型-蚀变岩型;韧性剪切带...     

贵州省金矿资源分布特征及开发利用布局建议

贵州省金矿资源丰富且分布广泛,包括岩金、砂金和伴生金三类,主要以岩金为主,砂金和伴生金较少。按矿床类型划分,岩金分为卡林型金矿、石英脉型金矿和红土型金矿。文章介绍了贵州省金矿资源分布特征、金矿资源勘查开发利用现状和不同矿床类型金矿资源分布特征。根据贵州省金矿资源分布相对集中的特点,划分出册亨—兴仁金矿矿集区、锦屏—天柱金矿矿集区,并提出了贵州省金矿开发利用布局建议和政策建议。     

微细浸染型金矿床及其成矿作用

微细浸染型金矿是找矿潜力很大的一种矿床类型。近几年来逐渐将其作为一种独立的矿床类型加以研究和勘查。本文综合有关研究成果。总结了微细浸染型金矿成矿地质条件和矿床特征。并在此基础上讨论该类矿床的成矿作用。提出层控地下热卤水成矿作用。层控有机成矿流体作用和层控深源成矿流体成矿作用是该类矿床的三种主要成矿作用。该类矿床的成因类型总体上可以归属于层控热液改造型矿床。     

湖南前寒武系金矿特征及成矿规律

湖南前寒武系金矿主要分布于湘西NE-NEE向雪峰弧形构造带、湘东北NE向幕阜山-九岭隆起构造带和湘中E-W向构造-岩浆岩带按其控矿构造和载矿岩石类型,可划分为石英脉型和破碎带蚀变岩型两个主要类型文章在对不同类型金矿地质特征进行述评的基础上,归纳了研究区内金矿成矿控制因素与成矿规律,指出:区内地层、岩浆岩、矿产分布严格受到深断裂控制,矿床的成矿具有显著的层控效应,沿倾斜发育较深与侧伏成矿和柱状富集规律,以及垂直分带现象,这对于找矿实践具有十分重要的意义.矿床成因类型主要为变质热液型,部分矿床受岩浆热(动)力作用或后期叠加成矿作用影响使其富化.此外,尚可能存在斑岩型或含金斑岩型矿床.文章提出湖南前寒武系金矿主要找矿类型为破碎带蚀变岩型,次为石英脉型,同时还应对含金斑岩或斑岩型金矿作深层次的找矿研究.     

铜陵天马山硫金矿床地质特征及成因探讨

天马山硫金矿床的矿体分为层状矿体、接触带矿体和穿层矿体。层状矿体和穿层矿体受石炭系黄龙组、船山组地层层位和层间断裂控制。接触带矿体受接触带控制 ,具矽卡岩型矿体典型特征。矿床的形成受地层、构造及岩浆岩控制 ,矿床成因为层控矽卡岩型硫金矿床     

国内外微细浸染型金矿床研究现状及发展趋势

微细浸染型金矿床,亦称为"卡林"型金矿床,是60年代初期发现的一种热液金矿新类型,广泛分布于美国西部、我国西南部及秦岭地区,是目前国内外重要的金矿床类型之一.本文从其概念、形成地质背景、层控性及矿源层、矿物组合及金的赋存状态、成矿模式及热液成矿机制等方面,概述了当前对该类金矿床研究和认识现状,并就其发展趋势提出了自己的看法.     

金的活动态分析方法及其应用

在金相态分析方法的基础上,对金活动态分析方法进行了如下改进:用5 μm孔径的滤膜取代2 μm孔径的滤膜抽滤;将加入提取剂溶液提取黏土吸附相、有机结合相和铁锰氧化物相改为直接加入固体提取剂;将泡沫塑料吸附-原子吸收法改为甲基异丁基酮(MIBK)萃取-原子吸收法测定金。介绍了改进后的金活动态分析方法及其在东北高寒森林覆盖景观某金矿区的一个应用实例。结果表明,除水提取相异常相对不明显外,其余3个相在矿体上方均有清晰、明显的异常指示。其中有机结合相的异常强度最大,是在该景观条件下寻找隐伏矿的最有利相态。重复样分析的相对误差小于50%,满足金的活动态分析要求。     

贵州省盘县架底金矿床成矿地质条件及找矿方向

架底金矿床位于贵州省莲花山背斜南东翼,距背斜核部3 km,是近年来在国内发现的与峨眉山玄武岩密切相关的第一个大型原生金矿床。架底金矿床与黔西南其他金矿床类似,属微细粒浸染型,成矿流体来源具有岩浆水的特点。玄武岩是矿区最主要的赋矿地层,玄武质火山角砾岩是矿区最主要的容矿岩石。矿化趋势分析显示：莲花山背斜（次级揉褶）与近东西向复式背斜的叠加区是有利的成矿部位,控制矿床中各矿体的分布规律及产出特征;近东西向复式背斜直接控制了矿体近东西向展布的特点,且越靠近莲花山背斜核部,矿体品位越高、厚度越大。原生晕地球化学分析指示：在矿区目前已发现矿体的顶部可能还存在断控型或层控型金矿体;源自深部的含金热液沿深大断裂上涌至一定位置后沿层间破碎带由东向西运移,且至少经历了2次主要的成矿作用阶段。综合研究认为整个莲花山地区具有较好的找矿远景,区内金矿床在南北方向可能按一定规律呈等距、不等距分布,推测东西方向受叠加褶皱控制的有利成矿区距莲花山背斜核部超过5 km。区内除峨眉山玄武岩外,在上二叠统龙潭组以及三叠系中都有可能在构造有利、岩性适宜的部位形成层控型或断控型金矿体。     

甘肃阳山金矿安坝矿段土壤中金的相态分析

从甘肃阳山金矿安坝矿段土壤样品中,分离提取金的8种化学相态(硫化物结合态、游离态、有机质结合态、水溶态、铁锰氧化物结合态、离子交换态、碳酸盐结合态、残渣态),用石墨炉原子吸收法测定各相金含量,并查明其分布特征。结果表明:安坝矿段上覆土壤中,金主要以游离态、硫化物结合态、有机质结合态3种形式存在,分别占总量的3.3%~75.9%,0~37%,3.3%~26%。平均含量分别为105.5×10-9,30.5×10-9,25.3×10-9。土壤中游离态金相对含量的峰值和活动态金相对含量的谷值均出现在矿体上方,指示着已知金矿体的赋存部位。因此,可利用游离态金或活动态金作为类卡林型金矿的找矿指标。     

甘肃省安家岔金矿床矿物包裹体研究

本文从石英包裹体的气液相成分分析数据和均一温度测定结果出发,计算出矿床的成矿压力、成矿热液的物理比学参数及其化学成分特征参数。结合矿床地质特征对矿床的成矿温度、矿床成矿热液的性质和来源、热液的流动方向、热液化学成分与金矿化的关系、热液中金的迁移形式和沉淀机制等问题作了进一步地探讨。结果表明,安家岔金矿床具有改造型金矿床的成因特点。     

Geology,geochemistry and sulphur isotopes of the Hat Han gold–antimony deposit,NE Vietnam

The Song Hien Rift basin is considered as one of the important regions for gold deposits in North East Vietnam. Host rocks of a number gold deposits in the Song Hien Rift basin are mainly in Lower Triassic sedimentary formations. However, there is the Hat Han gold deposit hosted in fined-grained mafic magmatic rocks with similar characteristics as gold deposit hosted in the Triassic sediments. Sulphur isotopic compositions of sulphide are similar to those in carbonaceous shale, suggesting that the sulphur was ‘borrowed’ from sedimentary rocks in filling the rift basin. Gold-bearing sulphides (pyrite and arsenopyrite) are the main form of Au presence in the ore. Gold in pyrite is present as Au^+ 1, and a minor amount of as nanoparticles of native Au (Au⁰); whereas in arsenopyrite, gold is chemically bound as the octahedral complex AuAs₂. Analysis of geology, as well as geochemical and isotopic studies show that the genesis of the Hat Han gold deposit is not related to the Cao Bang mafic magmatism; instead the latter only serves as (ore) host rock. The geochemical results presented above suggest that the gabbro host rock only supplies iron needed for sulphide formation. With regard to ore genesis, the Hat Han gold deposit in the Song Hien rift basin was generated in the similar way as sediment-hosted gold deposit. There are many similar typomorphic features between the Hat Han deposit and Carlin-like deposits in the Nanpanjang sedimentary basin in China.     

Episodes of Cenozoic Gold Mineralization on the Eastern Margin of the Qinghai-Tibet Plateau:~(40)Ar/~(39)Ar Dating and Implication for Geodynamic Events

A lot of new gold deposits have been found on the eastern margin of the Qinghai-Tibet Plateau during the past two decades. Among them, three main types of gold deposits have been recognized, including quartz-vein-type, shearzone-type and porphyry-type. The former two types of gold deposits are mainly hosted within metamorphic rocks, while the latter is related to Cenozoic magmatism. Although all of these gold deposits are believed to have been formed during the uplift process of the Qinghai-Tibet Plateau in the Cenozoic era (Wang et al., 2002b), precise isotopic age constraints have still been lacking until quite recently. This paper presents new ^40Ar/^39Ar data of some gold deposits on the eastern margin of the Qinghai-Tibet Plateau, which indicate that gold mineralization in the region occurred in response to the episodic stages of the orogenies. Recently obtained ^40Ar/^39Ar data on quartz and feldspars from several gold deposits, such as the Sandiao deposit, the Baijintaizi deposit, the Pusagang deposits, provide new constraints on gold mineralization on the eastern margin of the Qinghai-Tibet Plateau. Geochronological studies of gold deposits along the Daduhe River indicate that there are three stages of gold mineralization. The early two stages occurred as early as 65.1 Ma in the Shuibaiyang deposit and 58.95 Ma in the Ruoji deposit, while the latter stage occurred as late as 25.35 Ma in Baijintaizi and 24.70 Ma in Sandiao. Isotopic dating of three plagioclases from the Beiya deposit, Zhifanggou deposit and Luobodi deposit and a K-feldspar from the Jinchangqing deposit in Yunnan Province indicates that these deposits were formed at two stages. The Zhifanggou and Jinchangqing deposits have early stage records as old as 58.82 Ma in Zhifanggou and 55.49 Ma in Jinchangqing, but all of the above four deposits in Yunnan have late stage records of 23.18 Ma in Jinchangqing, 24.54 Ma in Zhifanggou, 24.60 Ma in Luobodi and 24.56 Ma in Hongnitang. The above results suggest that the gold deposits on the eastern margin of the Qinghai-Tibet Plateau were formed concentratedly at two main episodes, i.e. the end of the Paleocene (about 58 Ma) and the boundary between the Paleogene and the Neogene (about 25 Ma). The later episode appears to be looks like more important and was coupled with the Sichuan movement, which was extensively activated at that period. The beginning of the Cenozoic Era (about 65 Ma) might be another episode of gold mineralization, but only one deposit (Shuibaiyang) in this study has been proved to have been be formed at this stage and might be earlier than the initial collision between the Indian Plate and the Eurasia Plate. In view of geology, the above three episodes of gold mineralization are associated with three events of tectonicmagmatism and/or fluid events. Even though the gold deposits (for example, the Shuibaiyang deposit, Ruoji deposit and Pusagang deposit) were formed at different episodes, all of them are genetically related to tectonic movements in largescale shear zones. It looks like theat tectonic events (including large-scale strike-slip) between Paleogene and Neogene had a wide influence upon gold mineralization, with new deposits formed and old deposits enriched or superimposed to be a higher grade by new stage of mineralization. The above data suggest that gold deposits were not only concentrated in some areas, but also formed mainly at different boundaries of geological times, indicating that there existed some peak stages of gold mineralization (metallogenic episodes), and that the gold deposits were formed mainly by episodic mineralization.     

云南红土型金矿床地质特征及成矿条件研究

红土型金矿是云南找金工作的主攻类型之一。云南新构造期运动是红土型金矿的主成矿期,地壳的快速抬升,古气候与古地貌的变化,表现出红土型风化壳剖面发育不全,成熟度低,厚度不大,对基岩含金性依存度高等特点。云南红土型金矿成矿作用为红土化作用的初、中期阶段,其金矿类型有岩控型、层控型和构控型三种。     

贵州省泥堡金矿床矿体类型及其形成机理的新认识

根据贵州省西南部泥堡金矿床深部勘探成果,开展其矿床的矿体类型及其形成机理的综合研究,取得新认识如下:(1)矿区的主矿体不是层控型,而是断控型。断控型矿体的单个矿体规模大,厚度、品位较稳定,而层控型金矿的单个矿体规模小,厚度及矿石品位变化大;(2)虽然矿床的形成受到多种因素控制,但构造、地层及其有利岩性是关键的控制因素,尤其是断裂构造因素。F1逆冲断层既是导矿构造又是容矿构造,本矿床最大的金矿体就赋存于F1断裂破碎带中的减压扩容带,即断层破碎带变宽及断层面变缓部位。这两点新认识对区域找矿具有一定指导意义。