山西运城蚕房金矿成矿地质特征及成因浅析

蚕房金矿是中条山西南段典型的岩浆热液石英脉型金矿,矿脉呈雁行状产出于花岗闪长岩体内、外接触带。金矿化主要受次级北北东向断裂构造控制,均为单脉型金矿体。成矿模式可概括为：燕山期构造活动在区内局部构造薄弱带发生剪切深融作用,形成了过渡性地壳同熔型花岗闪长岩体,岩体的侵位并同熔部分矿源层以及岩浆的结晶分异作用,产生含矿热液,后伴随构造变动含矿热夜充填构造裂隙形成矿化石英脉体。主要控矿因素为花岗闪长岩体、北北东向断裂构造及褐铁矿化石英脉。     

剪切带与金矿床—构造控矿问题

集数十年至百年金矿研究经验，认识到剪切带构造不仅是控矿因素，而且也是一种重要的成矿机制。含金剪切带型金矿是一类既包括一些脉型矿床，也包括一些层控浸染型矿床的以剪切作用为成矿机制和控矿因素的金矿床。在构造控矿方面具如下特点：1．金矿床或金矿化带的空间分布明显地受韧性剪切带的控制。尽管金矿化带的成因、物质来源以及形成时间等提出了一些不同的成因模式，但其地质事实是金矿化带几乎都产在韧性剪切变质带内部或在其附近的后期（或晚期）构造裂隙中。如印度的科拉尔（Kolar）金矿。2．金矿化带的形成受特定的韧性剪切变质…     

石泉羊坪湾金矿床韧性剪切带特征及找矿标志

羊坪湾金矿位于巴山弧形断裂东侧，矿区总体构造为-呈NW走向的紧闭褶皱，金矿体受北西向展布的脆-韧性剪切带控制，剪切带内窗棂褶皱、小褶曲、微褶皱劈理、节理构造及片理化带相当普遍，特别是金矿化蚀变带内及近旁更为发育；另外，岩石的显微组构也反映强烈的揉皱构造、岩石裂隙、碎裂结构、碎斑结构等，这些对金元素赋存有利；早期形成金的矿源层，在韧性剪切作用下，使金元素被激活并发生迁移，在软硬岩层的接触面附近或断裂处聚集形成金矿体；金矿化与褐铁矿化、纤维状黄铁矿、细粒黄铁矿化和石英脉关系密切；进而总结了该区8条找矿标志。     

坦桑尼亚西北部苏库马绿岩带含金石英脉成矿特征

坦桑尼亚克拉通西北部的苏库马绿岩带是坦桑尼亚环维多利亚湖绿岩带重要的金矿聚集区。区内金矿化类型以含金石英脉为主,矿体的产出主要受剪切构造带控制。通过研究区域构造特征和岩石地球化学特征,认为苏库马绿岩带中玄武岩为弧后环境形成,流纹岩和花岗岩形成于陆弧环境,N--S向挤压作用和E--W向伸展作用是区域内主要的构造展布特征。建立了含金石英脉的成矿模式,表明具有金矿化作用的石英脉集中分布在EW、SEE、NE向剪切构造破碎带中,含金石英脉富矿体的形成经历了多期构造变形和成矿流体的叠加、富集作用。     

北京市怀柔区北干沟金矿床与韧性剪切带的关系

北干沟金矿床是韧性剪切带含金石英脉型金矿床。韧性剪切带以发育糜棱岩和片理化带为特征,应变强度和退化变质作用从边缘到中心逐渐增强,并形成鞘褶皱;韧性构造岩具有分带性;产于韧性剪切带中心部位的石英脉是主要的含金脉体;韧性剪切带的形态、活动阶段及韧性剪切变质岩的分带性对金矿具有明显的控制作用。     

黔东南地区金矿控矿构造的空间关系分析

黔东南地区金矿的构造控矿特征明显,所有金矿几乎都分布在背斜构造上,控制金矿产出的构造主要有受顺层滑动和切层破裂构造控制的石英脉、断层破碎带和剪切带等三种类型,以剪切带和顺层破裂构造控制的石英脉对成矿最为有利。这些控矿构造与褶皱作用关系密切,有的控制了褶皱的演化,有的为褶皱过程中形成的的次级构造。笔者在系统研究区内金矿控矿构造特征的基础上,分析了各类控矿构造与褶皱的空间关系,建立了金矿控矿构造的空间关系模式。     

云南墨江镍金矿床主要控矿因素分析与研究

采用控矿因素分析研究，通过构造岩石地层及构造变形筛分探讨镍金矿床的成矿过程，认为本区金镍矿主要为地层及构造控矿。在矿床内，热（泉）水喷溢构造（成矿构造）有似环状粘土岩化带及热水同生沉积－交代－喷流构造岩石层序，脆－韧性剪切带（储矿构造）由近水平的纵张裂隙构造、左行共轭剪切裂隙及相对封闭的脆韧性剪切带组成。脆性张剪性X形微裂隙系统为富金矿脉的定位提供了构造空间。成矿演化过程为：①晚泥盆世热水同生沉积成岩成矿期形成含金黄铁矿硅质岩；②印支期逆冲推覆型脆韧性剪切构造成岩成矿期形成含金脆韧性剪切带；③燕山－喜马拉雅山期深源热流体叠加成矿期形成富金矿脉。指出3处成矿远景区，认为红土型金矿很可能是本区一种新的金矿类型，值得重视研究。     

刚果(金)东北部太古宙绿岩型金矿地质特征及找矿方向

绿岩型金矿是刚果(金)重要的金矿类型之一。刚果(金)东北部的金矿床以内生金矿为主,次为外生金矿,内生金矿中主要为构造控制的脉状金矿床。典型矿床为基巴里绿岩带中的基洛矿区,矿化主要发生在发生碳酸盐化岩石的片理、剪切带和褶皱裂隙中;其次为受片理控制的浸染状金矿床,主要位于基巴里绿岩带的摩托矿区,矿化通常与围岩的片理相一致,并发育碳酸盐化等蚀变。研究认为,金矿床中的金质主要来源于绿岩带,太古宙岩浆活动形成了金的第一次富集,后期绿片岩相变质作用和强烈的蚀变造成了金的活化,并最终沉淀在构造裂隙中成矿。文章还总结了金矿床的找矿标志,并为区域金矿勘查方法提出了建议。     

夹皮沟剪切带中金矿脉形成化学动力学

夹皮为剪切带中存在着两种类型金矿化：（１）片糜岩型金矿化，（２）黄铁矿石英脉型金矿化（脉）。在韧性剪切阶段，围压较大，△Ｖｒ＜０，不能产生流体压力，也不能形成金矿化；随着剪切带演化，围压降低，产生了流体压力大于围压，即面△Ｖｒ＞０，产生了流体压力裂隙，并有矿化作用形成。矿化早期形成片糜岩型金矿化主要由流体压力裂隙所控制，而黄铁矿石英脉型金矿化则是由流体压力及岩石应力性质所决定。由片糜岩型金矿化转化为黄铁矿石英脉型金矿化是一个漫长地质时期，但由流体产生的成矿裂隙时间较短，大约为４０～８０ａ。     

河北金厂峪金矿控矿构造特征与成矿物质来源

金厂峪金矿是我国华北板块北缘大型金矿床之一,矿床产在晚太古宙褶皱绿岩带中,矿石类型主要包括含金钠长石脉和含金石英脉两种.控矿构造研究表明,在两期区域性褶皱作用下,形成的金厂峪复背斜及与之相关的北北东向挤压片理化带是金厂峪金矿的主要控矿构造.在片理化和蚀变过程中围岩斜长角闪岩的Fe2O3、CaO、MgO等成分被明显带出,...     

陕川丁家林-太阳坪金矿带成矿机理

丁家林-太阳坪金矿带与丁家林-太阳坪脆-韧性剪切带同位分布、同能源作用、同步生成，是脆-韧性剪切变形形成的石英脉型金矿，总体走向NE，主要由丁家林和太阳坪2个金矿床组成，分石英单脉、单脉密集带、复脉带3个亚型。丁家林以含Au石英复脉为主，太阳坪以含Au石英单脉为主；成矿物质来源于富含Si质的志留系黄坪组，成矿流体主要是构造水；内生成矿作用分脆．韧性剪切变形-构造分异热液期和韧-脆性剪切变形-构造分异热液期，与2期脆-韧性剪切变形相对应，第2期为主成矿期。其成矿机理是脆-韧性剪切变形动力成岩成矿。     

Geochronology of Gold Deposits and Its Implication for Metallogenesis in the Fengxian-Lixian Area, Qinling Orogenic Belt, China

Abstract: A series of super large‐scale and large‐scale Pb and Zn, and Au deposits are distributed in the Qinling orogenic belt, China. Gold deposits were generally ascribed to Carlin‐type originated from circular meteoric water. Visible and coarse‐grained gold (up to over 3mm in grain size) was recently identified in some gold deposits in the Fengxian‐Lixian area, Qinling. Au‐bearing quartz lodes related to magmatism were discovered in the Xiaogouli gold deposit. Two types of Au‐bearing quartz veins, i.e., NW‐trending quartz veins and NE‐trending quartz veins cutting strata are widely present in the Baguamiao gold deposit. Both are spatially associated with each other. The former is generally snake–like, S‐shape or zigzag, which was resulted from plastic deformation by ductile shearing, being generally cut by the latter. The latter is generally linear with widely developed bleaching alteration zones in its adjacent wall rocks, which symbolizes the superimposition of brittle deformation and filling and metasomatism of magmatic hydrothermal solution in ductile shear zones after uplifting of the shear zones near the surface. The NW‐trending quartz veins contain Au of lower than 3ppm. The NE‐trending quartz veins contain Au of more than 3 ppm, so that NE‐trending quartz veins and the adjoining altered rocks are important ores. The NW‐trending Au–bearing quartz vein was dated as 210.61.26 to 232.581.59 Ma by ⁴⁰Ar–³⁹Ar method, i.e., late Indosinian epoch (Triassic). The NE‐trending Au–bearing quartz vein was dated as 131.910.89 to 197.451.13 Ma by ⁴⁰Ar–³⁹Ar method, i.e., Yanshanian epoch (Jurassic). The ⁴⁰Ar–³⁹Ar age of the NW‐trending Au–bearing quartz veins represents the age of the ductile shear formation. The isotope data of the NE‐trending quartz veins indicate that gold mineralization was closely related to Indosinian and Yanshanian granite intrusives not only in time and space, but also in origin.     

The geology of the Taparko gold deposit, Birimian greenstone belt, Burkina Faso, West Africa

The Taparko gold deposit, located in the eastern branch of the Proterozoic Birimian Bouroum-Yalogo greenstone belt (Burkina Faso) consists of a network of quartz veins developed in a N 170° trending shear zone (250 m wide, 4 km long) superimposed on the regional Birimian structural pattern. The quartz vein network is composed of: (a) a dominant array of quartz veins (type 1), parallel to the shear zone and comprising strongly deformed dark quartz exhibiting foliation, layering, ribbon, tension gashes, etc.; (b) oblique and subparallel related veins (type 2) of gray to white weakly deformed quartz crosscutting the dominant quartz veins resulting in breccia structures; and (c) shallow dipping veins (type 3), cross-cutting veins types 1 and 2 and filled by undeformed white buck structure quartz. Cross-cutting relationships and different quartz types in different veins and within individual veins imply a concomitant filling of the veins during the progressive deformation. Initial sinistral transcurrent shearing evolved with time to sinistral reverse shearing. Metallic minerals occur only in type 1 and 2 veins and were deposited in two stages, with native gold being related to second stage sulfides. Gold (and chalcopyrite) precipitated preferentially upon the surfaces of fractured pyrite grains in low-pressure sites (pressure shadow zones) around and/or within the sulfide grains (along subsequently annealed fractures). The formation of the South Taparko deposit can be divided into a succession of events: (a) during the first event, N 170°-directed sinistral transcurrent shearing resulted in a N 20° mylonitic foliation and fractured rock which allowed H₂O-, CO₂- and SiO₂-rich fluids to circulate and deposit quartz with buck texture; (b) during the second event, type 1 quartz was strongly deformed and type 2 veins formed with sigmoidal shapes as viewed on a horizontal plane; and (c) during the third event, the sinistral transcurrent shearing evolved to sinistral reverse shearing and the deformation style evolved correspondingly from ductile to brittle-ductile. During the last phase of deformation gold nucleated and deposited in low-pressure zones. Received: 9 July 1997 / Accepted: 23 March 1998     

Orogenic Gold Mineralization in the Qolqoleh Deposit, Northwestern Iran

The Qolqoleh gold deposit is located in the northwestern part of the Sanandai‐Sirjan Zone, northwest of Iran. Gold mineralization in the Qolqoleh deposit is almost entirely confined to a series of steeply dipping ductile–brittle shear zones generated during Late Cretaceous–Tertiary continental collision between the Afro‐Arabian and the Iranian microcontinent. The host rocks are Mesozoic volcano‐sedimentary sequences consisting of felsic to mafic metavolcanics, which are metamorphosed to greenschist facies, sericite and chlorite schists. The gold orebodies were found within strong ductile deformation to late brittle deformation. Ore‐controlling structure is NE–SW‐trending oblique thrust with vergence toward south ductile–brittle shear zone. The highly strained host rocks show a combination of mylonitic and cataclastic microstructures, including crystal–plastic deformation and grain size reduction by recrystalization of quartz and mica. The gold orebodies are composed of Au‐bearing highly deformed and altered mylonitic host rocks and cross‐cutting Au‐ and sulfide‐bearing quartz veins. Approximately half of the mineralization is in the form of dissemination in the mylonite and the remainder was clearly emplaced as a result of brittle deformation in quartz–sulfide microfractures, microveins and veins. Only low volumes of gold concentration was introduced during ductile deformation, whereas, during the evident brittle deformation phase, competence contrasts allowed fracturing to focus on the quartz–sericite domain boundaries of the mylonitic foliation, thus permitting the introduction of auriferous fluid to create disseminated and cross‐cutting Au‐quartz veins. According to mineral assemblages and alteration intensity, hydrothermal alteration could be divided into three zones: silicification and sulfidation zone (major ore body); sericite and carbonate alteration zone; and sericite–chlorite alteration zone that may be taken to imply wall‐rock interaction with near neutral fluids (pH 5–6). Silicified and sulfide alteration zone is observed in the inner parts of alteration zones. High gold grades belong to silicified highly deformed mylonitic and ultramylonitic domains and silicified sulfide‐bearing microveins. Based on paragenetic relationships, three main stages of mineralization are recognized in the Qolqoleh gold deposit. Stage I encompasses deposition of large volumes of milky quartz and pyrite. Stage II includes gray and buck quartz, pyrite and minor calcite, sphalerite, subordinate chalcopyrite and gold ores. Stage III consists of comb quartz and calcite, magnetite, sphalerite, chalcopyrite, arsenopyrite, pyrrhotite and gold ores. Studies on regional geology, ore geology and ore‐forming stages have proved that the Qolqoleh deposit was formed in the compression–extension stage during the Late Cretaceous–Tertiary continental collision in a ductile–brittle shear zone, and is characterized by orogenic gold deposits.     

新疆青河科克萨依韧性剪切带型金矿床的构造演化模式

科克萨依金矿床为典型的韧性剪切带蚀变糜棱岩型金矿床,它与克孜勒它乌推覆构造系统有着十分密切的内在成因联系,其变形作用以韧性变形为主,具典型的深层次变形构造组合特点,其成矿过程可划分为３个重要的构造演化阶段,即早期的剪切片理化阶段、中期的变形分解阶段和晚期的液压致裂阶段,从而建立了该剪切带金矿床的构造演化模式。早期的剪切片理化阶段仅具微弱的金矿化;中期变形分解过程中,含金流体的渗流导致水热蚀变和金在递进缩短应变域的大规模沉淀,形成了主成矿期的金矿化;在晚期液压致裂阶段,含金流体涌入张裂隙,形成高品位、小规模的含金石英脉。     

冀北东坪金矿床深部-外围的构造-蚀变-流体成矿研究

冀北东坪金矿田是我国首次在碱性杂岩体内发现的金矿床,曾被认为是与碱性岩有关的金矿床。近年来年代学数据表明,东坪-后沟一带金矿的赋矿碱性杂岩体形成于海西期,而成矿却主要发生在燕山期。金矿床严格受构造裂隙控制,构造-蚀变-流体成矿作用显著,钾长石化是最重要的蚀变。由未蚀变岩石向矿体和断裂带中心方向,典型的构造-蚀变-矿化分带依次为:0-原岩(二长岩、正长岩)带,I-微斜长石化带,II硅化绢云母化微斜长石岩带,III碎裂微斜长石岩带,及IV断层泥。从0带到III带,Au含量增加,Ag、Cu、Pb、Zn、Mo也略有增加。东坪金矿构造-蚀变-矿化阶段可分为4个:Ⅰ钾长石-石英脉阶段;Ⅱ黄铁矿-白色石英阶段;Ⅲ多金属硫化物-烟灰色石英脉阶段;Ⅳ晚期碳酸盐阶段。深部中段各阶段脉石英的流体包裹体研究表明, 在I、II、III阶段均发育富CO₂包裹体。第Ⅰ阶段钾长石石英脉L-V型包裹体均一温度(Th)为220.3~359℃,盐度1.1%~3.1% NaCleqv;H₂O-CO₂型包裹体Th在346.5~383.5℃。第Ⅱ阶段黄铁矿白色石英脉中L-V型包裹体Th范围是217.2~372.5℃,盐度在1.1%~5.7% NaCleqv;H₂O-CO₂型包裹体Th在241.2~396.7℃,盐度为2.2%~6.2% NaCleqv。第Ⅲ阶段的烟灰色石英脉中L-V型包裹体Th范围为158.2~350.5℃,盐度在0.7%~5.5% NaCleqv;H₂O-CO₂型包裹体Th范围在215.2~378℃之间,盐度范围在3.0%~6.0% NaCleqv。第Ⅳ阶段晚期石英脉L-V型包裹体Th范围为151.2~249.8℃,盐度在0.9%~8.3% NaCleqv。矿区外围转枝莲矿段的II阶段白色石英脉中包裹体的Th范围为220~416.2℃,III阶段烟灰色石英脉的Th范围为195.3~425℃。富金石英脉形成于中高温(＞300℃,可达400℃以上)、中深压力(70~160MPa以上)条件下。其成矿背景、热液蚀变、矿物共生组合及流体性质与典型的造山型金矿有一定的差别,归属于"与侵入岩有关的金矿床"更合理。     

萨瓦亚尔顿金矿床磁组构特征及与金矿化关系

利用萨瓦亚尔顿金矿区岩石磁化率各向导性参数和金含量数据,研究了磁组构与金矿化的关系,结果表明强变形带内的弱应变域是金矿化的有利部位。本文把该金矿区韧性变形带内金的成矿作用归纳为3个阶段:(1)金矿化的物质准备阶段,形成富金地层或母岩;(2)矿化流体的萃取阶段,韧性变形作用可能是其主要动力;(3)金矿体的形成阶段,处在韧性变形之后的弛豫阶段(相对张性环境).在这里,韧性变形被看作是金成矿作用的一个必不可少的动力机制和中间环节。      

青海双朋西-斜长支沟地区金矿成矿地质条件及成矿规律

双朋西—斜长支沟地区是青海东部较为重要的贵金属和有色金属成矿区。在已探明的金矿床中,有矽卡岩型、破碎蚀变岩型、石英脉型三类。金的成矿作用受构造-岩浆控制,在不同的岩性组合中分布着不同类型的金矿。矽卡岩型和石英脉型金矿赋存于二叠系中,破碎蚀变岩型金矿赋存于三叠系中。     

小秦岭成矿带金矿化垂向分带规律及其地质意义

本文分析了小秦岭成矿带金矿化不同矿化类型、石英脉型金矿化不同矿化阶段及不同金矿床类型在垂向上的变化特征,确立了金矿化在垂向上的分带规律。在此基础上,探讨了深部"第二矿化段"存在的可能性,推断了金矿化的剥蚀深度及矿脉在深部的矿化特点,为金矿床的深部预测提供了可靠的依据。     

一些与韧性剪切带有关的金矿地质特征

目前,在世界范围内已发现越来越多的金矿赋存于韧性剪切带中,根据其主成矿期与韧性剪切带形成时间的关系可分为同韧性剪切型金矿和韧性剪切后型金矿。同韧性剪切型金矿主成矿时代同容矿韧性剪切带的发生、形成是同步的,韧性剪切活动不仅为成矿提供了空间,而且与成矿直接有关,容矿围岩为超糜棱岩、糜棱岩、初糜棱岩等,靠化学品位圈定矿体,矿石类型以浸染状为主;韧性剪切后型金矿成矿时代明显晚于韧性变形期,二者间隔时间较长,剪切活动仅为成矿提供空间,矿石类型完全取决于成矿前之容矿带的变形特征。