陕西省风太层控铅锌矿床地球化学特征及其成因探讨

凤太层控铅锌矿床赋存于中(?)盆统古道岭组灰岩与星红铺组千枚岩接触带或隐伏背斜构造鞍部,受地层、构造控制明显;有清楚的硅化、铁白云石化、炭沥青化等围岩蚀变现象,主要矿石矿物为闪锌矿、方铅矿、黄铁矿、黄铜矿及毒砂等。根据矿物包裹体、矿石和上下盘围岩组分比值、矿石矿物微量元素分布、硫铅同位素组成、区域围岩元素丰度等一系列特征,推测矿质极可能来自深部古加里东岛孤基底,后经海西—印支期构造作用,通过地下热卤水渗流,再到上部有利圈闭空间富集成矿。矿床成因类型基本属古生新储层控再造矿床。上部围岩也可能提供部分矿质,但主要矿源层应在深部。     

中朝古元古代层控铅锌矿床类型及其比较

中朝古元古代层控铅锌矿床属海底喷气沉积铅锌矿床。以地层对比与含矿层位为基础,以铅,硫同位素为重要信息,结合后期地质事件对矿床的影响与矿床主要成矿阶段不同,将这类矿床划分４个类型;受变质沉积层控铅锌矿床,受改造沉积层控铅锌矿床,变质热液改造型层控铅锌矿床和岩浆热液叠生型层控锌矿床。     

秦岭泥盆系层控铅锌矿床成因模式探讨

在论述秦岭泥盆系层控铅锌矿床的黄铁矿微量元素,硫、铅、氢、氧同位素,矿物气液包裹体均一温度及成分.区域地层元素丰度等方面特征的基础上,提出了该类型属海底含矿热泉溢出沉积和隐伏含矿热泉贯入沉淀的成因模式.     

广西北山铅锌黄铁矿矿床地质特征及其成因探讨

北山铅锌黄铁矿矿床位于广西壮族自治区环江毛南族自治县上朝镇北山村附近。目前,关于该矿床的成因尚存在争议,其中较具代表性的观点有:沉积-改造矿床,热卤水热液矿床,喷流沉积矿床。鉴于此,本文在阐述北山铅锌黄铁矿矿床地质特征的基础上,从含矿岩性组合、矿石矿物特征、区域白云石化等方面,对矿床的成因进行探讨,以期待为区域上同类型矿床的找矿勘探实践提供指导。     

贵池黄山岭层控矽卡岩及铅锌矿床成因

黄山岭层控矽卡岩为钙铝榴石矽卡岩，为奥陶系汤头组泥灰岩经热接触变质作用生成。铅锌矿体叠加在层控矽卡岩之上，成矿作用与富钾钙碱性岩浆岩密切相关的热液活动有关。成矿物质以岩浆热液来源为主，兼有变质热水活化转移的同生沉积矿源。     

湖南省泥盆系层控矿床

本文从湖南的实际情况出发,对泥盆系各类层控矿床成矿有关的一系列基本问题,诸如成矿条件与控制因素,成矿物质来源,矿床时空分布规律,成矿元素的迁移、淀积与组合、分带规律以及成矿的物理化学条件等进行了系统的阐述。提出了“层、相、位、源、障”五因素综合控矿模式。     

Proximal and distal stratabound ore deposits

Stratiform ore deposits associated with calc-alkaline and tholeiitic volcanism form as chemically precipitated sediments and, like other sediments, display facies variations. An attempt to characterise these vertical and lateral facies variations and to relate them to distance in time and space from the volcanic centre is presented here. With increasing distance in time and space from a volcanic centre, the proportions of volcanics to sediments and intensity of hydrothermal alteration decrease. Footwall alteration pipes, stringer and disseminated ore zones dominated by quartz-, sericite- and Mg-rich assemblages are spatially associated with proximal stratiform base metal deposits whereas slight alteration to quartz-, sericite- and Fe(Mn)-bearing assemblages are present associated with distal stratiform base metal deposits. With increasing distance in time and space from the volcanic centre the Fe, Cu and S content of base metal deposits decreases and the Zn, Pb, Ag, Mn, Ba and F content increases. The trend from copper-dominated to zinc-lead-dominated iron sulphide ores is probably a result of the increasing mixing of seawater with metal-bearing hydrothermal fluid with increasing distance from the volcanic centre.     

Stratabound lead-zinc pyrite ore deposits in upper precambrian carbonate rocks,Rodna Mountains,Romania

The Blazna-Guset mining area is located in the Rodna Mountains, Eastern Carpathians, North Romania. It is mostly covered by the metamorphic rocks of the Rebra Series (Upper Precambrian; K/Ar dating gave 800 m.y.). The middle part of this series — called the Carbonate Formation — contains lead-zinc pyrite ores hosted by prevailingly carbonate rocks. The ores form flat and thin lenses occurring together with fine intercalations of silicate-, graphite- and quartz-bearing rocks within the calcite-dominated limestones. Pyrite, ironpoor sphalerite and galena are the main ore minerals. Chalcopyrite, pyrrhotite and magnetite also occur in small amounts. Within the highly deformed and partly recrystallized parts of the ore bodies bournonite, arsenopyrite and pearceitepolybasite were locally encountered. Ba, Ti and Mn are the most significant ore-accompanying elements.     

Peloids in stratabound Zn-Pb deposits and their genetic importance

Peloids from sediment-hosted Zn-Pb deposits in Belgium, Ireland and Poland are composed of Zn-calcite, siderite, smithsonite, silica, pyrite, melnikovite, sphalerite, galena, thiosulphates and Zn-As-bearing limonite. The size of peloids is between 7 and 60 m. The core and the shell of peloids are composed of different minerals and the shell is usually coarsely crystalline. Peloids are present in collapse breccias of karst cavities, stromatactis cavities, debris-flow breccias, and fractures cross-cutting carbonates hosting the mineralization. In places peloids form a major microtexture of the sulfide mineralization. Peloids are cemented and replaced by sulfides. Organic acids extracted from sulfide peloids are composed of amido-acids considered to be characteristic of bacterial origin. The size and specific texture of peloids are independent of mineralogy, location and age of the mineralization. Therefore the peloids disussed are considered as forms induced by bacterial activity rather than forms precipitated inorganically.     

Diagenetic pyrite from the lead-zinc deposits of Zawar,India

Pyrite from the Precambrian lead-zinc deposits of Zawar, West India, shows excellent sedimentary features, viz., composite bedding, lenticular bedding, flame structure etc. which are attributed to turbidites. Early diagenetic pyrite occurs as framboids and isolated euhedral as well as subhedral grains. Most of the isolated grains are probably derived from the breaking of unconsolidated framboids. Diagenetic crystallization of pyrite became operative during an early stage of deposition and continued to modify the initial sedimentary fabrics.     

青海省典型铁矿矿床特征及其成矿系列的浅析

青海省铁矿床（点）成因类型可划分为镁铁-超镁铁岩浆成矿系列的结晶分异型矿床；壳幔型中酸性岩浆成矿系列的热液型、矽卡岩型矿床；火山喷流-沉积成矿系列的层控型矿床；叠加改造成矿系列的层控改造型、改造热液型、沉积变质型矿床；沉积喷流成矿系列的层控型矿床；沉积成矿系列的陆、海相沉积型矿床．通过对这些成矿系列的典型铁矿矿床特征的研究，从其成矿构造地质环境分析，许多铁多金属矿床（点）均具有形成大型以上矿床的成矿地质条件，且多伴生铜、铅、锌、金银等多金属矿产。研究认为，在今后的找矿勘查过程中，应利用成矿系列的规律，并注重对共（伴）生组分的综合评价，这对扩大全省的找矿远景，提高资源综合利用水平，提高铁矿床技术经济价值具有重要的意义。     

小兴安岭地区与加里东期花岗岩类有关的矿床成矿系列

加里东期花岗岩类岩浆活动及其有关的成矿作用，在小兴安岭地区形成了一批铁、铜、锌、铅、锡、钼和钨等矽卡岩型和热液型的矿床。这些成因上紧密相关的矿床形成时间相近。不过，在不同的岩浆活动阶段和不同的地质环境中形成的矿床，，其矿化特征又有明显的差别，而且，矿种和矿化类型在空间的分布上，呈现有规律的分带象。本文着眼于研究上述的矿床所处的地质背景、成矿条件和成矿作用，用成矿系列的观点，对矿床进行矿亚系列和矿床     

黑色岩系型矿床的形成作用及其在我国的产出特征

贵州下寒武统牛蹄塘组黑色页岩富集了以Ni、V为主的伴生元素,并且富有机质,目前金属元素Ni、V与有机质的共富集机制尚不清楚,但有机质在金属离子的富集、迁移和转化的过程中具有重要作用。探究金属元素作用对有机质结构的影响有助于准确地认识有机质和金属元素的共富集机制。本文以胡敏素为研究对象,分别与Ni、V两种金属标准溶液混合后恒温振荡,通过元素组成、X射线光电子能谱（XPS）和固体核磁共振碳谱（¹³C-NMR）由表到里揭示金属溶液作用前后胡敏素结构的变化特征。结果表明：胡敏素的元素组成以C、O为主,Ni、V两种金属溶液作用后,均造成胡敏素中O和S元素的相对含量减少,C和N元素的相对含量增加。XPS测试显示,胡敏素表面的C元素主要以芳香碳形态赋存,O元素则主要以羟基氧形态赋存;对于不同赋存形态的C元素,Ni、V金属溶液作用后对其影响趋势一致,均使芳香碳、羟基碳和羰基碳减少,主要破坏芳香碳(C—C/C—H)单键;而对于不同赋存形态的O元素,Ni金属溶液作用后则使羟基氧和羧基氧减少,使其中的富氢富氧官能团脱出,V金属溶液作用后则使羰基氧和羧基氧减少,破坏其中的羰基双键(C=O)。¹³C-NMR测试显示,作用前后的胡敏素有机质芳香结构主要以单环或者双环结构存在,两种金属溶液均能使氧接芳碳（$f_{\\rm{ar}}^{\\rm{P}} $）和桥接芳碳（$f_{\\rm{ar}}^{\\rm{B}} $）中的富氧富氢官能团从芳环中脱出、胡敏素中脂链长度变短、有机碳的稳定性降低、活性有机碳含量减少以及疏水程度变小。通过对比分析表明,胡敏素对Ni、V金属元素具有一定的氧化能力,两种金属溶液作用后均能使胡敏素中C、O元素的赋存形态发生改变,Ni金属溶液主要影响脂肪碳结构,V金属溶液则主要影响芳碳结构。

     

南岭锡钨多金属矿区碱长花岗岩的厘定及其意义

南岭地区锡钨多金属矿成矿作用主要与燕山早期花岗岩岩浆活动有关,这些花岗岩一直被认为是黑云母花岗岩、二长花岗岩、细粒二长花岗岩等,少量矿区岩体顶部出现钠长石花岗岩。通过对湖南瑶岗仙钨矿岩体的深入解剖,以及对杮竹园、黄沙坪、锡田、邓阜仙、栗木、梅子窝等矿区花岗岩全面的岩矿鉴定和电子探针分析,确定钨矿区致矿花岗岩的长石主要为碱性长石,其中绝大部分样品中钠长石An<5,因此确定这些花岗岩均属于碱长花岗岩。与成矿有关的由浆液过渡态流体形成的云英岩包体中的钠长石更加富Na,An<3。碱长花岗岩的成分以及钠长石成分在岩体顶部约1 000 m深度范围内无明显垂向变化。致矿花岗岩体中部分早期花岗岩包体、晚期花岗斑岩,部分花岗岩基以及印支期花岗岩、加里东期花岗闪长岩等,钠(斜)长石An值明显高,很多属更长石、中长石甚至基性长石。这种包含有两种碱性长石的碱长花岗岩由富挥发分的岩浆形成,在岩体顶部附近广泛发生液态不混溶作用,是导致锡钨多金属矿富集成矿的主要分异方式。钨锡矿区碱长花岗岩钠长石An值明显低于区域大花岗岩基或不致矿花岗岩,可作为花岗岩的钨锡成矿评价标志之一。