湘中古台山金锑矿床变形序列、成矿事件及控矿构造

湘中古台山金锑矿位于雪峰构造带西南段东北部,发育SN向金矿脉和NW向金锑矿脉2类矿脉。前人提出SN向和NW向断裂为容矿构造,并获得了印支期成矿的⁴⁰Ar-³⁹Ar同位素年龄,但对容矿断裂的性质、形成时代以及2类矿脉的时代关系缺乏研究和认识。鉴于此,文章通过地表和井下露头构造以及矿化蚀变的观测、解析,结合区域构造特征、区域构造演化和测年资料等,厘定了古台山金锑矿区构造变形序列及其时代、不同类型矿脉的成矿时代和构造背景,探讨了构造控矿规律及动力机制。主要认识如下：(1)研究区自早至晚经历了5期主要变形事件：志留纪晚期受到NWW向挤压,形成NNE向板劈理、NNE向褶皱(水车背斜)、SN向顺层断裂、逆冲剪切破裂和断裂;中三叠世晚期受到NNW向挤压,局部形成NEE向轴面劈理;晚三叠世受到SN向挤压,形成EW向褶皱、NW向—NNW向右行走滑断裂和剪切破裂、NNE向左行走滑断裂和剪切破裂、EW向逆冲剪切破裂等;中侏罗世晚期受到NWW向挤压,形成EW向右行剪切破裂和断裂;古近纪中晚期受到NE向—NNE向挤压,形成SN向—NNE向右行剪切破裂和断裂、EW向—N...     

兴蒙造山带中与古亚洲洋演化有关的成矿系统初步研究

古亚洲洋演化过程中在兴蒙造山带中形成了大量金属矿床。早古生代早期,古亚洲洋向北俯冲,形成了奥陶纪多宝山-铜山斑岩Cu-Au成矿系统;早古生代晚期,古亚洲洋向南俯冲并形成了晚奥陶世白乃庙Cu-Mo-Au成矿系统和志留纪别鲁乌图海底喷流块状硫化物成矿系统。古亚洲洋在晚古生代早期向北俯冲,形成了晚泥盆世欧玉陶勒盖Cu-Au成矿系统。基本同时,古亚洲洋向南俯冲,形成了晚泥盆世哈达门沟Mo成矿系统。早石炭世,研究区构造体制从岛弧环境逐渐转变为陆内伸展环境,并在此过程中形成了豆荚状铬铁矿成矿系统和小型斑岩Mo-Cu成矿系统。     

闽浙沿海火山岩地区银矿成矿规律

本根据闽浙沿海火山岩地区银矿成矿规律和成矿预测的研究及近年来的矿产勘查，成矿预测和专科研成果，综合论述了闽浙沿海火山岩地区银矿的成矿地质条件，矿床类型和矿床特征，分析和总结了银矿的成矿规律和成矿作用，建立了区域成矿模式和成矿系列，同时指出，火山热液充填充代型银矿是本区最重要、也是最普遍的成因类型，并阐明了找矿方向。     

成矿元素的离子结构及其在花岗岩成矿过程中的 行为

研究表明,不同类型岩石的形成导致不同类型元素的富集成矿,而后者与元素的自身结构密切相关:具惰性气体型离子结构的元素亲沉积岩,具过渡型或铜型离子结构的元素亲岩浆岩。进一步研究发现,陆壳大规模熔融 固结,亦即花岗岩的形成过程,不但导致不同类型元素在上陆壳及其上层圈重新分配:亲氧(造岩)元素占据壳内熔融(岩浆)层的位置,亲硫(成矿)元素迁移到岩浆层上覆盖层且其中副族成矿元素按离子半径增大的顺序沉淀析出,亲水元素迁移到水圈而亲气元素则回归大气圈;同时揭示了与陆壳地质结构相适应的陆壳元素地球化学结构,体现了自然界微观和宏观的协调与和谐。     

宁镇地区内生金属矿床类型及成矿系列

矿床类型及其特征为有利于指导找矿和矿床评价,矿床分类的基本原则应该是:(1)既不是成因分类亦不是工业分类,而是以成因为基础,以工业意义为主导的两者有机结合;(2)以“多因成矿”观点指导矿床分类,从宁镇地区内生金属矿床的实际情况出发,既考虑岩浆热液成矿作用,亦重视层控或沉积改造等成矿作用的影响;(3)分类方案力求简明实用,能基本概括目前该区内生金属矿床的主要类型。     

新疆维权银多金属矿床富砷矿物特征及意义

新疆维权银多金属矿床为新疆首次发现的独立银矿床,通过偏光显微镜和电子探针等大型仪器,对矿石中的富砷矿物斜方砷铁矿与毒砂进行分析.结果表明:银矿物多与斜方砷铁矿相伴生,毒砂的富集要早于银矿物和斜方砷铁矿,指示在矿床成矿阶段存在一个贫硫阶段和一个富硫阶段,对矿区成矿期次进行了划分,对矿床成因进行了探讨.     

Trace Elements in Fluid Inclusions in the Carlin—Type Gold Deposits,Southwestern Guizhou Province

Fluid inclusions in quartz from the Lannigou and Yata Carlin-type gold deposits in southwestern Guizhou were analyzed by inductively coupled plasma-mass spectrometry for their trace elements(Co,Ni,Cu,Pb,Zn,Pt,etc.).The results show that quartz fluid inclusions entrapped at different ore-forming stages contain higher Co,Ni,Cu,Pb and Zn.It has been found for the first time that the ore-forming fluids responsible for the Carlin-type gold deposits are rich in Pt.From this it can be concluded that basic volcanic rocks seem to be one of the important sources of ore-forming materials for the Carlin-type gold deposits.     

http://www.sciencedirect.com/science/article/pii/S1674987112000357

Field and remote sensing studies reveal that Au-bearing quartz±carbonate lodes in Romite deposit,in the extreme South Eastern Desert of Egypt,are controlled by NNE-striking shear zones that splay from the ca.660—550 Ma Hamisana Zone.Quartz in releasing bends with sinistral shear geometry and abundant boudinaged quartz-carbonate lodes with serrate ribboned fabrics suggest vein formation throughout a transpressive wrench system.Ubiquitous hydrothermal quartz,carbonate,and subordinate chlorite and sericite within the shear zones and as slivers in veins,indicate that gold deposition and hydrothermal alteration occurred under greenschist fades conditions.The Al（Ⅳ） in chlorite indicates a formation temperature of～300℃.comparable with temperatures estimated from arsenopyrite composition for grains intimately associated with gold in quartz veins. The new geological and geochemical data indicate that splays off the Hamisana Zone are potential gold exploration targets.Quartz veins along the high order（2nd or 3rd） structures of this crustal-scale shear zone are favorable targets.In the Romite deposit and in surrounding areas,a Au-As-Cu-Sb-Co-Zn geochemical signature characterizes mineralized zones,and particularly rock chips with>1000 ppm As and high contents of Cu,Zn,and Co target the better mineralized areas. The carbonateδ¹³C_pdb andδ¹⁸O_Smow isotope signatures preclude an organic source of the ore fluid,but metamorphic and magmatic sources are still valid candidates.The intense deformation and lack of magmatism in the deposit area argue for metamorphic dewatering of greenstone rocks as the most likely fluid source.The narrow ranges ofδ¹³C（-4.6‰to -3.1‰） andδ¹⁸O（11.9‰-13.7‰） in carbonate minerals in lodes imply a corresponding uniformity to the ambient temperature andδ¹³C_CO2(δ¹³C_∑C) of the ore fluids. The calculatedδ¹⁸Oh₂o values of 6.9‰—7.9‰for ore fluids,based onδ¹⁸O values of vein quartz further suggest a likely metamorphic origin.