内蒙古孟恩陶勒盖银多金属矿床及其附近侵入岩的年代学

孟恩陶勒盖是内蒙古东部地区的一处大型银多金属矿床,铅锌银矿体呈脉状产出,受东西向断裂控制。对孟恩陶勒盖矿区及其外围主要侵入岩体开展了年代学和地球化学研究。LA-MC-ICP-MS锆石测年结果表明：孟恩陶勒盖岩基中黑云母斜长花岗岩的锆石年龄为（240.5±1.2） Ma,MSWD=0.48;白云母斜长花岗岩的锆石年龄为（234.3±3.2） Ma,MSWD=0.21;矿区外围杜尔基岩基中的黑云母正长花岗岩的锆石年龄为（154.5±0.5） Ma,MSWD=0.41;矿区外围的安山玢岩的锆石年龄为（127.5±0.7） Ma,MSWD=1.3;分别代表了中三叠世、晚侏罗世和早白垩世的3期岩浆活动。岩石地球化学分析结果表明：孟恩陶勒盖岩基的黑云母斜长花岗岩和白云母斜长花岗岩与杜尔基岩体的黑云母正长花岗岩均为富SiO₂、富碱、准铝的钙碱性岩石,具有轻稀土分异明显、富集大离子亲石元素（LILE）为特征,其中Ba、Nb、La、Sr、P、Ti相对亏损,而Rb、Th、K、Ta、Ce、Nd、Hf、Sm、Y 和Yb相对富集。岩体年代学和岩石地球化学特征表明,孟恩陶勒盖岩基和杜尔基岩基分别形成于印支期的碰撞造山和燕山期的伸展构造环境。根据获得的侵入岩的测年数据与前人获得的孟恩陶勒盖银铅锌矿与成矿有关的蚀变白云母的Ar-Ar年龄(179. 0士1. 5) Ma对比显示,这些侵入岩的侵位年龄与成矿年龄之间差别较大,说明这些岩体不太可能是孟恩陶勒盖银铅锌矿床的成矿母岩。成矿岩体可能在深部尚未出露,或者已被杜尔基岩体改造。     

湘西自治州北部铅锌矿找矿标志及找矿远景区

湘西自治州北部铅锌矿带,处于桑植复向斜西南段,长100km以上,宽50km左右,矿带内铅锌矿点广布,受地层、构造、岩性的控制。上寒武统耗子沱群至下奥陶统大湾组共有7个含矿层位,北东向背斜倾伏端及北东向断裂、层间裂隙以及次级北西向横跨背斜是矿床控矿构造,有矿体赋存的含矿层有明显的硅化作用,且硅化体中Pb,Zn,Cu明显富集,分别为地层的66、32、8倍,Sr/Ba比值为0.60,无矿存在的硅化体则Pb,Zn,Cu含量接近地层或稍高于地层,Sr/Ba比值高达1.15。在砂子坡背斜南翼、红岩溪背斜北东端和南西倾伏端、盐井背斜,下奥陶统红花园组顶部含矿层内为找矿远景区。     

Late Paleozoic Fluid Systems and Their Ore-forming Effects in the Yuebei Basin, Northern Guangdong, China

Based on detailed and systematic researches of the geology of ore deposits, fluid inclusions and isotope geochemistry etc., and regarding the Late Paleozoic fluid system of the Yuebei Basin as an integrated object in this paper, we have revealed the temporo-spatial evolution law of the basin＇s fluid system and discussed its ore-forming effects by simulating and analyzing the distribution of ore-forming elements, the fluid thermodynamics and dynamics of evolution processes of this basin. The results show that Late Paleozoic ore-forming fluid systems of the Yuebei Basin include four basic types as follows. （1） The sea floor volcanic-exhalation system developed during the rapid basin slip-extension stage in the Mid-Late Devonian, which affected the Dabaoshan region. It thus formed the Dabaoshan-type Cu-Pb-Zn-Fe sea floor volcanic-exhalation sedimentary deposits. （2） The compaction fluid system developed during the stable spreading and thermal subsidence-compression stage of the basin in the Mid-Late Devonian. The range of its effects extended all over the whole basin. It resulted in filling-metasomatic deposits, such as the Hongyan-type pyrite deposits and pyrite sheet within the Fankou-type Cu-Pb-Zn-S deposits. （3） The hot water circulation system of sea floor developed during the stage of basin uplifting and micro-aulacogen from the late Late Carboniferous to Middle Carboniferous. The range of its effects covered the Fankou region. It thus formed MVT deposits, such as the main orebody of the Fankou-type Pb-Zn-S deposits. （4） The gravity fluid system developed during the stage of fold uplifting and the basin closed from Middle Triassic to Jurassic, forming groundwater hydrothermal deposits, e.g. the veinlet Pb-Zn-calcite orebodies of the Fankou-type Pb-Zn- S deposits. Migration and concentration of the ore-forming fluids were constrained by the state of temporo-spatial distribution of its fluid potential. Growth faults not only converged the fluids and drove them to move upwards, but also the fluids often crossed the faults to the edges of the basin at the bottom of these faults and the lithologic interfaces, and even migrated to the basin＇s edges from top to bottom along the faults, which may be one of the basic reasons for the stratabound deposits to cluster mainly along the contemporaneous faults on the inner border of the basin. The superposed mineralization resulting from the multi-stage activity of contemporaneous faults and ore-forming fluid systems in the basin may be one of the key factors for forming superlarge ore deposits.     

澳大利亚世纪铅锌矿床地质特征和成矿模式

澳大利亚世纪(Century)铅锌矿床赋存于中元古代劳恩希尔组页岩和粉砂岩中。矿化主要为细粒闪锌矿,其次为方铅矿和黄铁矿。大部分硫化物(80%~90%)在黑色页岩单元中以易碎的交代层状出现,被富菱铁矿粉砂岩层隔开。矿化具有2个大尺度的变化趋势,在白蚁圈断层由北东至南西,Zn品位显著降低,由南东至北西,Zn品位略有降低。层状闪锌矿主要有2种结构,多孔闪锌矿的焦沥青含量较高,无孔闪锌矿焦沥青含量较低。S同位素研究显示,整个成矿流体系统是一个封闭的储层,重S在变形与成矿事件中进一步富集。世纪矿床由变形作用驱使流体迁移到异常高压(压实作用下的)页岩层位时,页岩容矿的矿化作用形成。较热的富含金属的流体和较深盆地的卤水,使得有机质迅速成熟,最终导致硫酸盐的还原和贱金属的沉淀。     

滇西惠民式铁矿找矿模型及预测

惠民铁矿产于双江陆缘弧带中元古代惠民岩组中部多旋回含铜铁火山-沉积建造中。每个小旋回底部由火山岩始,顶部至铁矿层终,构成明显的火山喷发-沉积韵律,铁矿层的大小、分叉、尖灭等,与火山岩的多寡、厚薄直接有关,受控于火山岩活动及其中心。将其厘定为云南省云县-澜沧一带区域性的中元古代海相火山-沉积型铁矿典型矿床-惠民式铁矿,并将与之成矿条件类似的双江-澜沧地区中元古代火山岩盆地作为惠民式铁矿的预测工作区,以MRAS定位定量方法,基于GIS矿产资源评价系统进行矿产预测,优选最小预测靶区13个,估算铁矿石资源量75亿吨,做为今后寻找与勘查该类型矿床的依据。     

姑婆山复式岩体的基本特征及其与成矿作用的关系

姑婆山复式岩体由晚侏罗世里松岩体、姑婆山岩体及早白垩世新路岩体组成。复式岩体为壳幔混合源成因。据岩石地球化学判断和分析,姑婆山岩体和新路岩体为含锡岩体;整个姑婆山复式岩体为含钨岩体,里松岩体和姑婆山岩体为含稀有、稀土岩体。上述矿产的形成与岩石中挥发份F、B及放射性U、T h等元素的高含量有关。     

陕西煎茶岭超基性岩与金矿床成因关系

煎茶岭金矿床属于与超基性岩有成因联系的微细浸染状构造蚀变岩型金矿床。该超基性岩沿超壳断裂侵位（９２７Ｍａ）,是金矿形成的矿源岩。含矿超在性岩在强烈的构造变形作用下,发生彻底的退化蚀变（３８８．７Ｍａ）。经滑石－蛇纹石化,进而碳酸盐化,导致微量金解离。在后期活动性断裂控制下,形成含金硫化物矿化－硅化－碳酸盐化蚀变岩体的就位。．含金蚀变岩与金矿体微量元素组合、稀土元素、稳定同位素组成对超基岩有明显的继     

我国重晶石矿床成因及成矿远景综述

我国重晶石矿床的形成受大陆裂谷系、弧-盆系和陆内挤隆系三种大地构造环境控制,多数矿床形成于大构造旋回的早期阶段,并与一定的岩相古地理环境及岩浆活动有关。矿床可划分为外生成因[沉积型、风化（残积坡积）型]和内生成因（火山-沉积型、层控型、热液型）等不同类型。成矿之钡源主要来自深部的火山-气液。矿床多在中、低温,弱酸性向弱碱性过渡的氧化环境的硫酸盐型成矿溶液中形成。中国重晶石矿具有较好的找矿前景,在一些工业需求地区,有发现新矿床的可能。     

霍什布拉克铅锌矿床成因研究

矿体赋存在上泥盆统坦盖塔尔组上段碎屑岩向碳酸盐岩过渡部位，具有双层结构。矿石组构具有明显的热水沉积成因特征，研究表明：矿床成矿物质主要来源于深部寒武-奥陶系的基底地层。矿床系下渗的海水和大气水混合淬取了基底丰富的成矿物质形成上升热卤水在海盆中喷流沉积而成。     

云南会泽超大型铅锌矿床成因研究中的几个问题

位于川-滇-黔铅锌多金属成矿域中南部云南会泽超大型铅锌矿床可能是一种新的铅锌矿床类型，该类铅锌矿床明显特征是规模大、品位富、伴生有用元素多，暗示其成矿环境较为特殊。从成矿时代、成矿物质来源、成矿流体来源与演化，以及峨眉山玄武岩与成矿的关系等方面分析了会泽超大型铅锌矿床的研究进展及国内外研究现状，认为矿床成矿时代与西南大面积峨眉山玄武岩成矿时代相近，成矿物质和成矿流体具有“多源性”，成矿流体存在均一化过程，区域大规模流体运移在该区铅锌成矿过程中具有重要意义，峨眉山玄武岩岩浆活动与铅锌成矿具有密切的成因联系，矿床可能为“均一化成矿流体贯入成矿”的产物。