Fluidization: An Important Process in the Formation of the Qiyugou Au-bearing Breccia Pipes in Central China

Fluidization processes based on experiments are reviewed to gain some useful insights and comparisons with those that occur in hydrothermal systems. Field and petrographic work, and microscope observation were carried out on samples from the Qiyugou Au-bearing breccia pipes from the East Qinling region, Henan Province. Evidence from macro- and micro-textures suggests that the style of breccias in the Qiyugou area can be grouped into three types： （1） jigsaw fit-stockwork texture, in which the interval between clasts is marked by fractures or filled with calcite or quartz veins; （2） larger breccias that are supported by smaller breccias, rock flour and alteration materials; in this type clasts moved over short distances, creating open spaces; （3） fluidized texture, where the clasts of different lithologies have rounded shapes. These observations are compared with those resulting from experiments on fluidization processes. The results of this comparison suggest that fluidization is an important geological process in the formation of the Qiyugou Au-bearing breccia pipes and gold mineralization. In addition, fluidization processes such as expansion, bubbling, slugging, channeling and spouting must have contributed to the formation of the pipes and were conducive to the development of gold mineralization. In the Qiyugou breccia pipes, gold mineralization occurs as disseminations, in stockwork veins, and open space infills. The ore zones form subparallel sheets that are nearly perpendicular to the walls of the pipes.

Formation mechanism of breccia pipe type in Yixingzhai gold deposit

Based on the basic geological features of Yixingzhai gold deposit, the geological features, classification and relation to mineralization of breccia pipes were discussed by surveying the xenoliths and breccia's mineral composition, structure and construction, typical mineralization alteration phenomenon on field and microscopic anatomy in breccia pipes. And the ore-controlling mechanism and the formation mechanism of the blasting breccia pipes were investigated. The main conclusion shows that Hewan and Nanmenshan breccia pipes nearby the NW-striking deep fault are shaped earlier, belonging to the acidic siliceous ingredient production of ultra-hypabyssal magmatic in the late magma stage; Tietangdong and Nanmenshan breccia pipes that are shaped latter are the ultra-hypabyssal auriferous fluid production composed mainly of the skarn in the hydrothermal stage after the magma period. Both root in the unified deep magmatic chamber, belonging to differentiation derivatives at different stages in the deep magmatic chamber.

Qiyugou auriferous breccia pipes: A low-sulphidation epithermal system linked with transition of tectonic regime from collisional compression to extension, Xiong ershan, Henan, China

The Xiong’ershan area,as a part of a metallogenic province in cetral China,contains substantial Leimengou porphyry molybdenite deposit,Qiyugou breccia gold deposits and vein gold deposit occurred in fault zone,as well as previously refer to as orogenic gold deposit.Around or nearby the Mesozoic porphyry granite,the typical porphyry deposit,much more breccia pipes and breccia gold deposit are developed in the area.In this paper we focus on reporting preliminary results obtained from field,petrographic work on the Leimengou porphyry molybdenite and the Qiyugou breccia gold deposit,as well as laser Raman microspectroscopy and microprobe analyses carried out on samples from the Au-bearing Qiyugou breccia pipes.An adularia-calcite assemblage is reported in these breccia gold deposits.Two stages of hydrothermal alteration,pervasive and vein,are identified.The first stage consists of the alteration of the breccia clasts and rock flour by actinolite,green biotite,epidote,chlorite and minor sericite.This hydrothermal activity is likely to relate to the molybdenite mineralisation episode.The second stage is characterised by quartz veining and adularia and calcite filling open-spaces.Vein ores associated with quartz,sericite,and minor calcite alteration occur in NE-trending fault that cut the first stage of alteration.The adularia-calcite alteration is genetically associated with gold mineralization.The adularia-calcite assemblage in the area suggest that the Qiyugou pipes are of low-sulphidation epithermal in nature.The Qiyugou breccia pipes are coeval and spatially associated with the nearby Leimengou porphyry Mo deposit,which together conform to an alkalic mineralising system.We propose a model for the development and evolution of the breccia pipes in conjunction with a model that describes the genesis of the porphyry Mo and auriferous breccia pipes as a unified magmatic-hydrothermal system,which is linked with transition from collisional compressional to extensional geodynamic regime.

A New Type of Li Deposit:Hydrothermal Crypto-Explosive Breccia Pipe Type

Lithium is one of the important strategic energy metals,which is in short supply in China.There are three major types of lithium deposits:brine and salt lake type,highly differentiated granite or pegmatite type,and carbonate-clay type.In recent years,some new types of lithium deposits have also begun to receive great attention and subject recent research.There are many crypto-explosive breccia pipe type deposits in the world,including copper,gold,lead,zinc,tungsten and tin deposits,but little is known about this type of lithium deposit.This paper introduces the latest research results of the Weilasituo Sn-Li-Rb polymetallic deposit in Inner Mongolia(NE China),which occurs in the middlesouthern section of the Great Xing’an Range metallogenic belt.A remarkable feature of this deposit is the coexistence of various mineralization types,including granite type Rb and Sn-Zn,hydrothermal crypto-explosive breccia pipe type Li-Rb,quartz vein type Sn-Zn and sulfide vein type Pb-Zn-Ag mineralization.Among them,hydrothermal crypto-explosive breccia pipe type Li-Rb deposit is currently very rare at home and abroad,which is likely a new type of rare metal deposit that worthy of our attention.This paper systematically summarizes the geology,alteration and mineralization,geochemistry,isotopes and geochronology of the Weilasituo deposit,and establishes a new petrogenic and metallogenic model.

Fluids double-fracturing genetic mechanism and mineralization of gold-copper of the breccia pipe at Qibaoshan in Shandong Province

After studying the characteristics and special texture of the fluidogenous tectonics, mineral assemblage in the cemented vein between breccia and their special distribution, and stress analyzing the joint structures in and around the breccia pipe, it is found that the observed phenomena are caused by a new tectonic dynamic mechanics of fluid——double-fracturing caused bytemperature and pressure of fluids and pulsating expansion. Under the actions of thermal stress and the pressure of fluids, thermal cracks and joints that developed along parts of the thermal cracks formed systematically in the rocks. Under these conditions, up-arching fracture zones that pulsatively expanded upward and cylindrical pressing breccia body were formed. Rocks at the peak of the pyramidal fractures zone break down instantly. Where the difference between pressure of fluids and the overburden pressure exceeded greatly the competence of the rocks, fluid junctions occurred and the velocity of the fluid flow increased as a result. Explosive body expanded upward in the shape of an inverse cone, cone-like explosive breccia body and cover-like shattering breccia body located on the upper part of the breccia pipe were ultimately formed. Gold-rich fluids were enriched and mineralized near the boiling surface in the lower part of the inverse cone-like explosive breccia body where temperature and pressure decreased rapidly, while copper-rich fluids were enriched and mineralized in the junction area where temperature and pressure were relatively high.

安徽庐枞盆地黄屯隐爆角砾岩筒型金铜矿床碲元素的分布、分配特征及沉淀机制研究

隐爆角砾岩筒型金(铜)矿床作为重要的金矿床类型,常伴生关键金属碲的矿化,然而对于此类矿床中碲的分布、分配特征及沉淀机制研究仍较为薄弱。黄屯矿床是长江中下游成矿带近年来发现的最为典型的隐爆角砾岩筒型金铜矿床,伴生有大量的碲化物产出。本文在详细的野外地质工作和岩相学观察基础上,发现碲在矿床中发生了显著富集。通过对黄屯矿床不同蚀变类型矿石及主要富碲矿物开展全岩及微区地球化学分析,明确了碲的分布、分配特征以及初步讨论了碲的沉淀机制。黄屯矿床成矿阶段从早到晚可划分为钠钙硅酸盐、钾硅酸盐、绿泥石-碳酸盐和伊利石-蒙脱石阶段,在不同深度形成了相应的蚀变带,并发育有不同强度的金铜矿化。黄屯矿床伴生的碲储量约有118.71t,平均品位为5.3g/t,达到中型规模,具备重要的综合利用价值。钾硅酸盐蚀变带碲的分布比例最高,占总储量约92.37%,平均品位约为9.6g/t。钾硅酸盐蚀变带内约有89%~99%的碲呈独立矿物,主要以微米级、纳米级的碲铋矿包体的形式分布在黄铁矿中,剩余部分则以类质同象的形式赋存在黄铁矿和黄铜矿内。减压沸腾引起流体温度骤降导致硫化物沉淀,和沸腾过程中释放大量气相H_(2)S,共同导致流体的f(Te_(2))/f(S_(2))比值升高,可能是黄屯矿床中碲沉淀富集的主要机制。

山东省五莲七宝山金铜矿床成矿模式与找矿勘查模型——来自综合物化探的证据

山东省胶莱盆地南缘发现了多处火山机构,随着五莲七宝山角砾岩筒型金铜多金属矿的发现,说明胶莱盆地南缘具有良好的成矿前景。但从目前发现的矿床来看,无论是数量还是规模均与成矿条件不匹配,亟需总结该区成矿模式和勘查模型,为胶莱盆地南缘铜多金属矿勘查提供找矿方向及方法。本文以七宝山矿床为解剖对象,开展了地球物理和地球化学综合探测。研究发现七宝山杂岩体对应地球物理特征为高磁异常,隐爆角砾岩筒的γ能谱显示U元素、Th元素和能谱总量∑均为低异常,隐爆角砾岩筒在重力剖面上呈重力高异常。地球化学特征以Ag、Pb、Au、Cu元素异常为主,各元素异常套合好,主要元素具有明显的二、三级分带。以上物化探特征均是成矿作用特征标志。在此基础上给出了七宝山地区成矿模式,建立了综合找矿勘查模型,成功预测了隐爆角砾岩筒深部延伸特征,建立了七宝山地区陆相火山热液型矿床成矿模式和找矿勘查模型。

铁氧化物-铜-金(IOCG)型矿床：基本特征、研究现状与找矿勘查

国际上对IOCG型矿床的研究如火如荼,中国则刚刚起步。文章全面评述了IOCG型矿床的研究现状,包括IOCG型矿床的定义、全球时空分布特点、成矿环境、与成矿有关的岩浆岩、矿体形态特征及围岩蚀变、矿床的形成过程、找矿评价标志等。最后,文章从IOCG型矿床的角度,对中国某些矿床进行了思考,认为长江中下游宁芜和庐枞盆地内的玢岩铁矿可能属IOCG型矿床,河北邯邢铁矿和湖北大冶铁矿也有IOCG型矿床的某些特点。

河南祁雨沟热液角砾岩体型金矿床成矿流体研究

祁雨沟金矿床产于燕山期热液角砾岩筒内。通过对 4号角砾岩体胶结物和石英 -碳酸盐脉内流体包裹体研究表明 ,其中的包裹体类型非常复杂 ,有气体包裹体、气液包裹体、液体包裹体、含子矿物高盐包裹体和含 CO2 包裹体五种类型。成矿的初始热液为高温高盐流体 ,它们来源于燕山期花岗岩浆热液。由于角砾岩体的隐爆、流体减压沸腾及古大气水的混入 ,热液中的金被沉淀成矿 ,形成胶结物型和脉型金矿化。金矿的开始成矿于温度较高 (310～ 390℃ )的中阶段 ,并可能延续至中温(2 0 0～ 2 90℃ )

黑龙江金厂金矿床地质特征及成因探讨

通过对矿体围岩花岗闪长岩、花岗斑岩类和隐爆角砾岩筒控矿_容矿构造及矿石组分的研究 ,将金厂矿床金矿化类型分为破碎蚀变岩型、裂隙充填型和角砾岩型 ;对矿物学和同位素地球化学的研究结果表明 ,成矿物质主要来源于深部 (岩浆源 ) ,在成矿作用早期阶段成矿流体主要为岩浆水 ,晚期阶段有部分大气水的加入。金厂金矿床是中生代火山_次火山活动的产物 ,矿床属浅成低温岩浆期后热液型金矿床。

吉林敦化大石河钼矿床成因与辉钼矿Re-Os同位素测年

大石河钼矿床是近年来在小兴安岭—张广才岭钼成矿带南缘新发现的一个大型钼矿床。深部矿体产于似斑状花岗闪长岩体顶部,呈细脉浸染型;近地表矿体主要呈含辉钼矿石英脉,赋存于浅变质岩中。钼矿化受隐爆角砾岩筒及构造裂隙控制,矿化与蚀变具有明显的分带性,属斑岩型钼矿床。对采自矿区浅部矿体中的5件辉钼矿样品进行了Re-Os同位素测年,获得模式年龄(182.1±2.7)～(191.9±2.6)Ma,加权平均年龄(186.7±5.0)Ma,MSWD值为11.8,表明大石河钼矿形成于燕山早期。结合近年来小兴安岭—张广才岭钼成矿带上所获得的成岩成矿年龄数据,认为160～190 Ma是该钼成矿带的钼矿成矿作用的集中期。辉钼矿样品中Re含量为3.549～4.362μg.g-1,指示成矿物质为壳源。综合分析认为,大石河钼矿床为该区燕山早期大规模成矿事件的产物,形成于古亚洲构造域和环太平洋构造域叠加和转换期的构造环境。

山西灵丘支家地铅锌银矿隐爆角砾岩筒的岩相分带性研究及其勘查意义

隐爆角砾岩筒长期以来一直受到人们的重视,但是对于岩筒的通道相特征以及垂向分带则少有研究。本文通过对山西灵丘支家地铅锌银矿床详细的野外和岩相学研究工作,发现了含矿隐爆角砾岩筒的通道相,其多发育在石英斑岩-石英斑岩角砾岩小岩株的顶部,总体形态为角砾岩筒根部发育的间隔式分支脉状矿化蚀变带,岩体内反映为细脉中心向两侧呈弥散密集浸染状矿化蚀变的隐蔽裂隙脉,对隐爆角砾岩筒的形成机制具有重要的意义。进而根据含矿角砾岩筒不同部位的矿化类型,角砾的成分、形状、大小、可拼合性等特征,将其在垂向上由上而下分为4个相带:①裂隙相、②震碎相、③爆破相、④通道相。各相带的角砾成分、大小、形态、胶结物特征和矿化蚀变等呈规律性变化,震碎相和爆破相是最主要的赋矿部位,沿含矿角砾岩筒的通道相有可能追索到深部的斑岩型矿化。含矿角砾岩筒形成机制与岩浆上侵中第二次沸腾过程中岩浆热液释放有关。

锡铁山铅锌矿床网脉状蚀变管道相的识别与研究

锡铁山大型铅锌矿床属喷流沉积型,赋存于柴达木盆地北缘早古生代裂陷形成的滩涧山群火山-沉积岩中。矿床中产有非层状和层状两类矿体,其中非层状铅锌矿体呈不规则状产于大理岩中,是锡铁山矿床的主要矿体类型,层状铅锌矿体产于大理岩边部,规模较小。在矿床深部大理岩层上盘滩涧山群b岩组的绿泥石英片岩中,深部整合发育有强烈的钠长石化与硅化,主要呈角砾状和网脉状结构,构成网脉状蚀变带,主要成分包括石英钠长岩、蚀变的绿泥石英片岩以及硅化石英岩等,其连续长大于2km,宽大于200m,呈不规则岩筒状。石英钠长岩交代结构普遍,与绿泥石英片岩呈渐变接触关系,广泛发育热水爆破角砾。地质地球化学研究表明,网脉状蚀变岩并非侵入岩或火山岩,而是形成于热水交代作用,代表了喷流沉积系统的管道相,相当于矿体下部供给带。结合容矿大理岩及矿体研究发现,锡铁山矿床发育规模巨大的喷流沉积系统,包括长>2km的管道相、大规模的喷流沉积岩-大理岩,以及近喷口相未喷出海底地表的非层状矿体。现已发现的层状矿体与非层状矿体比例的倒置显示出锡铁山矿床仍然存在巨大的铅锌矿找矿潜力。网脉状蚀变带分布于矿体及大理岩的上盘,也表明锡铁山矿区容矿的滩涧山群a和b岩组产状整体发生了倒转,网脉状蚀变岩最初分布于铅锌矿体及大理岩之下。由于网脉状蚀变岩(石英钠长岩)与成矿系统的密切关系,它可作为柴达木盆地北缘滩涧山群中寻找铅锌矿的重要找矿标志。

冀东唐杖子金矿:一个典型的隐爆角砾岩型金矿

根据唐杖子金矿矿区野外观察和勘探结果发现，北东向深断裂F2、F3控制了辉绿岩一花岗斑岩组成岩浆带，在与近南北向断裂F1交汇处，岩浆气液活动增强，形成明显的隐爆角砾岩筒，从中心向外侧依次出现中心角砾岩带一崩塌角砾岩带—震碎角砾岩带的分带特征。在角砾岩筒南西侧的主断裂带（F2、F3）内，热液聚集形成含金黄铁矿石英脉，脉体规模大（长约3000多米，宽约25m），含金品位高（金品位最高45g／t，最低3．6g／t，平均8．44g／t），构成唐杖子金矿的主矿体；在角砾岩筒北侧的弧形断裂（F5-F17）和南侧的放射状断裂（F18～F22、F23～F27）中，也有不同程度的热液聚集，形成含金石英脉，Au品位一般在1．82g／t。由主断裂带、侵入岩带控制的爆破角砾岩带及其派生的含金断裂系统，靠近岩筒的脉体中，硫化物发育，含金品位高；随着离爆破角砾岩筒距离的增大，断裂系统中的硫化物逐渐减少，金品位逐渐降低，整体构成一个典型的爆破角砾岩筒型金矿。角砾岩筒型金矿的识别，对华北地台的相似背景区的金矿勘探和地质研究有借鉴意义。

江西会昌红山隐爆角砾岩筒及其成因和动力学

隐爆角砾岩、隐爆角砾岩筒及其成因研究，在国外已有近１００年、国内有近３０年历史。由于不同学者从各自的角度出发，提出的名词术语繁多，观点众说纷纭，同物异名者众，令人费解不说，更不便于交流，为此，该文以江西会昌红山隐爆角砾岩筒为例，从隐爆角砾岩、隐爆角砾岩体的概念、分类命名、描述和分布特征，以及隐爆角砾岩筒成因和动力学等加以探讨，以求得共识、推动研究深化的目的。

马来西亚沙捞越邦达、什兰江控矿角砾岩筒构造对比研究及其找矿意义

马来西亚沙捞越邦达、什兰江控矿角砾岩筒构造均为典型的浅成-半浅成角砾岩筒构造,角砾岩及控矿类型具有明显的垂向分带特点。邦达控矿角砾岩筒构造发育角砾岩筒上段的塌陷角砾岩,角砾岩筒剥蚀深度较浅,控制典型的高硫化型浅成低温金铜矿床,且其深部具有较大的找矿潜力。什兰江控矿角砾岩筒构造发育角砾岩筒下段的爆发角砾岩和中段的流化角砾岩,分别控制斑岩型金矿化和低硫化型浅成低温热液型金矿化,角砾岩筒剥蚀深度较大,对矿床的保存和找矿极为不利。

论角砾/网脉-斑岩型金矿

斑岩型金矿可分为伴生／共生－斑岩型、角砾／网脉型和单脉／网脉－斑岩型３类。角砾岩筒及其内部构造裂隙、角砾岩筒与围岩的接触带构造、与角砾岩筒有成生关系的断裂构造是斑岩型金矿的重要控矿构造。其由角砾状和网脉状矿石组成，两者又难以划分开，故称角砾／网脉－斑岩型金矿。我国本亚类斑岩型金矿中，往往伴有冰长石化（团结沟、义兴寨、祁雨沟等矿床），个别矿床伴有明矾石化（紫金山矿床），国外同类斑岩型金矿中罕见报道。

祁雨沟含金角砾岩筒中的冰长石方解石组合及其矿床地质意义

通过野外地质、岩相学、拉曼光谱和电子探针分析,对祁雨沟2号和4号含金角砾岩筒中冰长石方解石蚀变矿物组合特征进行了描述。含金角砾岩筒成矿作用分为两期:面状矿化和脉状矿化。面状矿化的蚀变主要有阳起石化、绿色黑云母化、绿泥石化、冰长石化、硅化、绿帘石化、黄铁矿化、碳酸盐化和少量的绢云母化。脉状矿化蚀变为硅化、绢云母化和少量的碳酸盐化。通过对角砾岩筒的蚀变与成矿作用关系研究,认为冰长石方解石蚀变与含金角砾岩金成矿作用是同期,从而确定祁雨沟含金角砾岩筒是一个典型的低硫型浅成低温热液型金矿床。

马来西亚沙捞越西部Punda金铜矿床构造控矿作用及找矿意义

沙捞越西部Punda金铜矿床为浅成—半浅成角砾岩筒控制的典型高硫化型浅成低温热液矿床。控矿角砾岩筒的分布受线性走滑断裂构造控制,角砾岩筒垂直分带明显。角砾岩筒上段的塌陷角砾岩与矿化关系密切,中段的流化角砾岩、边部的水压角砾岩和下段的爆发角砾岩还未出露。根据角砾岩的垂直分带特点,该角砾岩筒剥蚀较浅,矿床保存条件良好,具有较大的深部找矿潜力。

东川-易门式铜矿床成矿作用研究的几个问题

从宏观基础地质入手,按矿床学的一些基本概念,针对东川-易门铜矿床地质地球化学特征,探讨了一些存在争议的重要问题。研究认为:狮山段是绿汁江组下部独立存在的地层层位;东川-易门式铜矿床属沉积-改造成因,其中的层状铜矿属沉积成岩成因,不是"热液成矿";所谓东川-易门式矿床(稀矿山除外)为"喷流沉积成矿"或"岩浆叠加",尚依据不足;刺穿体是构造作用产物,对成矿有利,是良好的找矿标志,其中的角砾岩主要是沉积角砾岩与构造角砾岩,或沉积-构造角砾岩,不足以冠名"隐爆角砾岩(筒)"。