东升庙多金属硫化物矿床主要含矿岩系地质地球化学特征及对矿床成因的指示意义

东升庙矿床是内蒙古狼山-渣尔泰山成矿带上最大的锌多金属矿床,主要含矿岩系是狼山群第2岩组。通过对矿区地质现象的野外观察和钻孔样品地球化学特征的研究,结合国际上同类矿床最新研究进展,对东升庙矿床主矿体的成矿过程提出了新观点。岩、矿石样品的岩相学研究结果显示,不同岩段的岩、矿石有不同的组构特征：第4岩性段中部菱铁矿矿石为典型的细粒镶嵌结构和块状构造,具明显的化学沉积特征;第4岩性段底部②号矿体中的闪锌矿矿石具半自形-它形晶粒结构或溶蚀结构,多为角砾状构造或块状构造,有明显的充填-交代现象;第3岩性段以绢云石墨片岩为主的黑色岩系网脉状矿化普遍,常见后期热液充填现象。岩矿石样品的地球化学研究结果显示,菱铁矿矿石和闪锌矿矿石有相似的微量元素富集特征和稀土元素配分曲线,可能具有同一物质来源。而第3岩性段的绢云石墨片岩有不同的微量元素富集特征和稀土元素配分曲线,可能是多期热液活动作用的结果。值得一提的是,在②号主矿体硫化物矿石中不但发现有来自于矿体下部的有一定磨圆度的绢云石墨片岩碎屑角砾,还有一些来自上部围岩的含炭质白云大理岩角砾。此类碎屑角砾可能是交代残余或者交代过程中垮塌的产物,无法用同时沉积解释。综合分析认为第3岩性段的网脉状矿化是后期热液充填的结果,而第4岩性段底部的②号矿体是含矿热液选择性交代碳酸盐地层而成矿,菱铁矿矿体是富铁热液运移到海底后沉积生成。相对于传统的喷流沉积成矿方式,本文认为交代作用对东升庙主矿体的形成起到了关键作用。     

Sphalerite-bearing detrital ‘sand’ bodies in Mississippi Valley-type zinc deposits Mascot-Jefferson City district,Tennessee

The Mississippi Valley-type sphalerite mineralization in the Mascot-Jefferson City zinc district of East Tennessee occurs as open-space fillings in breccia bodies within the upper part of the Knox Group (Lower Ordovician) which is truncated by a regional unconformity. A lower age limit of mineralization is constrained by the formation of solution-collapse breccia bodies, which are believed to be related to the post-Knox unconformity. The breccias contain irregularly distributed “sand” bodies that represent cavities filled with well-laminated and size-graded, sphalerite-bearing, detrital, internal sediments. The texture, composition, and fluid inclusion characteristics of the sphalerite, are consistent with its local derivation from the wallrocks as detrital grains. The conformability between the laminations in the sediments and the bedding planes of the host carbonate rocks suggests that the sand bodies formed prior to the regional deformation event (Alleghenian orogeny). The stylolitization of carbonate and sphalerite clasts in the internal sediments as well as the deformation of the sphalerite are also consistent with a pre-Alleghenian age for the emplacement of the main-stage sphalerite mineralization in the Mascot-Jefferson City district and, by analogy, in other Lower Ordovician-hosted Mississippi Valley-type districts of the southern Appalachians.     

An Unusual Texture: Skeletal Sphalerite in Pyrite from Dajing Tin-polymetallic Deposit, China

Abstract. Skeletal sphalerite with stellar, cruciform and snowflake-like (or cauliflower-like) shapes included in pyrite is widely found in the Dajing tin-polymetallic deposit. It occurs only in chalcopyrite-pyrite mineralization stage. The compositions of all sphalerites in the chalcopyrite-pyrite stage are characterized by high Cu content (3.9 - 7.0 wt% with a mean of 5.4 wt%), while the skeletal crystal sphalerite has higher zinc and cadmium contents, and lower copper and iron contents, compared with other sphalerites of the same stage. The skeletal crystal sphalerite in pyrite is possibly generated by exsolution.     

扬子陆块东南缘升天坪锌矿床地质特征、闪锌矿Rb-Sr定年及其地质意义

升天坪锌矿床位于扬子陆块东南缘雪峰山地区,是湘西地区产于陡山沱组的中型锌矿床。采用同位素稀释法对主成 矿期闪锌矿进行Rb-Sr同位素组成分析,获得等时线年龄为490 Ma,初始锶同位素组成87Sr/86Sr为0.71235。该等时线年龄代 表了该矿床的主成矿阶段年龄,说明矿床形成的地质时代为晚寒武世,成矿作用发生于加里东中期。成矿作用时代与闪锌 矿初始锶同位素比值特征反映成矿物质或成矿流体由基底岩石（板溪群） 和震旦系碳酸盐岩地层共同提供。结合矿床地质 特征与区内铅锌矿成矿地质背景,认为周边板块碰撞的远程效应为热液成矿提供了构造驱动力,加里东期的构造运动对升 天坪锌矿床的形成起着重要作用。升天坪锌矿床严格受地层控制,矿床类型为沉积-改造型层控矿床。     

内蒙古小西沟铅锌矿床矿石特征及可选性试验研究

小西沟锌铅矿床属于低温热液型矿床,矿石组成复杂,伴生铜和银,研究表明,该矿床矿石中的铅、锌、铜和银主要矿化元素以独立矿物产出,但部分黄铜矿与闪锌矿呈固溶体交生。根据矿石性质确定,该矿床矿石可采用混合浮选铜铅(铜、铅分离)—再浮选锌的工艺流程,通过试验获得符合标准的铜精矿、铅精矿和锌精矿,所用药剂没有环境污染,符合当前技术条件,可以开发利用。     

Polymetallic Mineralization at the Nakakoshi Copper Deposits, Central Hokkaido, Japan

Abstract: Polymetallic mineralization at the Nakakoshi deposits, Kamikawa town, central Hokkaido, occur as fracture-filling veins in Cretaceous slate of the Hidaka Supergroup. Ten veins have been recognized in NE-SW and E-W directions. Sericite in altered slate which is the host of the deposits, was dated at 31. 1 Ma, Oligocene in age.
No. 9 vein consists of massive chalcopyrite ore with various kinds of minerals such as pyrite, pyrrhotite, arsenopyrite, sphalerite, tetrahedrite, Ag-minerals and Cu–Zn–Fe–In–Sn–S minerals, quartz and sericite. Chalcopyrite and pyrite contain sphalerite star and sphalerite with chalcopyrite emulsions. Maximum indium contents of sphalerite and the Cu–Zn–Fe–In–Sn–S minerals are 1. 8 and 16. 3 wt%, respectively. The sulfur isotopic ratios, δ³⁴S of ore minerals, range from –12. 9 to –9. 6%. Formation temperatures of the sulfide minerals are estimated as 300–500°C, based on the paragenesis and chemical compositions of the minerals.     

江西永平铜矿金属矿物化学成份及矿物包体特征

永平铜矿黄铁矿、黄铜矿的化学成份特征以及矿物测温和石英包体成份分析特征表明成矿经历了一个较低温度阶段，但所反映的后期成矿作用的改造特征也非常明显，特征是闪锌矿，其化学成份具明显的后期改造成矿特征，是岩浆热作用的产物。黄铁矿的同生成矿较为明显，闪锌矿的后期改造成矿特征更为明显，而黄铜矿具有明显的沉积改造特征。     

云南保山核桃坪铅-锌矿床地质特征

保山核桃坪铅-锌矿为一中型铅-锌矿床。矿体赋存于上寒武统核桃坪组,主要受近SN向的层间断裂(F1)及次级断裂构造控制,岩石(性)控矿也十分明显,成矿作用与矽卡岩化密切相关。通过对该矿床地质特征的系统分析以及对矿床围岩蚀变、控矿因素的深入研究,认为该矿床主要矿化作用是深部高温成矿流体贯入并与围岩发生矽卡岩化蚀变,随后发生矿化作用。矿床应属矽卡岩型铅-锌矿床。     

Mechanism of sulfide mineralization through successive metasomatic replacement stages of zoned host dolomite in Cracow-Silesian Zn-Pb deposits (Mississippi Valley type), Pomorzany Mine,Poland

Replacement of dolomite rhombs is zone selective in Cracow-Silesian Zn-Pb deposits. The discussed replacement of dolomite by sphalerite occurs as spotted sphalerite ore constituting about one-fourth of the economic sulfide mineralization of the Pomorzany Mine. Replacement is controlled by two factors, i.e., microporosity and chemical composition. The epigenetic host dolomite rhombs are zoned into three main zones, i.e., the outer rhombohedral rim which is hard and Fe rich with remarkable Zn content, the inner zone which is porous and Zn rich but usually low in Fe content, and the core of the dolomite rhombs which is Fe free but may contain some Zn. Zones rich in Zn were the first to be replaced by sphalerite; the same holds true for zones with higher microporosity showing a high degree of crystallographic disorder of cations. The other zones seem to be intact. There are four successive replacement stages, i.e., partial, moderate, intense, and advanced. During replacement the intact parts become more Zn-rich, consequently being replaced completely in the later stages, the greater the zinc content in the host dolomite is, the more reactive it is to replacement by sphalerite. The liberated iron from replaced Fe-rich zones is fixed as finely crystalline pyrite.     

上扬子地块东缘凹子岗锌矿床成矿流体特征

凹子岗锌矿床位于上扬子地块东缘,该矿床经历了两个成矿期:沉积成岩期和热液期,形成两种不同岩相学特征的闪锌矿。流体包裹体岩相学研究显示,存在盐水包裹体(W型)、烃类包裹体(G型)和含石盐子矿物多相包裹体(S型)。有机流体活动与成矿存在耦合关系,其中烃类包裹体(G型)赋存于白云石和自形粗粒闪锌矿中,具有黄色荧光效应,激光拉曼测试显示其成分为沥青质、CH_4、C_3H_8和H_2O;此外,沥青与闪锌矿密切共生。显微测温结果显示热液期流体包裹体均一温度集中于160~180℃,盐度集中于8%~14%NaCl_(eqv),部分可达30%NaCl_(eqv)左右。成矿流体除含有机质外,还含有NaCl、KCl、CaCl_2、MgCl_2、H_2O,为多元共存的流体体系,成矿压力为22~84 MPa。     

内蒙古得尔布干成矿带铅锌银矿两期叠加成矿的矿物学证据--以乌尔根矿为例

内蒙古额尔古纳市乌尔根铅锌银矿是得尔布干成矿带上具有代表性的浅成中低温热液型铅锌银矿之一。显微镜下观察、电子探针分析结果等矿物学证据证明,该矿床存在2期成矿作用。其中早期火山热液形成的金属硫化物普遍受应力作用的改造,并广泛被晚期形成的矿物交代,典型矿物是不含乳滴状黄铜矿的闪锌矿,具有高含量Fe、Mn和低含量Cu的特征;晚期次火山(隐爆角砾岩)热液形成的金属硫化物占大多数,常交代早期形成的矿物并与其交生在一起,典型矿物是含固溶体乳滴黄铜矿的闪锌矿,并且具有中等含量Fe、Mn和高含量Cu的特征。在次火山热液期的晚阶段残余热液还形成了较为纯净的呈棕黄色-无色透明的纯净闪锌矿,具有高含量Zn,低含量Fe、Mn、Cu的特征。结合前人测定的研究区火山岩和矿石矿物定年结果以及火山岩主量元素组成数据,推测早期火山热液成矿与中基性塔木兰沟组火山岩关系密切,而晚期次火山(隐爆角砾岩)热液属于满克头鄂博组的(中)酸性岩浆热液的产物。隐爆角砾岩热液富含Cu元素且为成矿提供了主要物质来源,是研究区寻找除铅锌之外其他矿种的重要线索。     

闪锌矿Cd、Fe含量与矿化阶段的关系

闪锌矿是在许多矿床中最常见的矿物.闪锌矿的Cd、Fe含量与矿化阶段关系的研究,可以推断矿液演化史和矿床形成环境变化史.对矿床评价及勘查有一定的指示意义.分析国内外200多个矿床闪锌矿Cd、Fe含量数据,有8个矿床注明了闪锌矿形成的矿化阶段.其中4个矿床早阶段产生的闪锌矿比晚阶段形成的闪锌矿富Fe、贫Cd,4个矿床早阶段结晶的闪锌矿比晚阶段形成的闪锌矿既富Fe,又富Cd.反映矿床形成的地质构造和物理化学环境,矿液来源及演化史绝然不同.     

新疆阿尔泰山南缘克兰盆地红墩SEDEX型铅锌矿

红墩铅锌矿床位于克兰裂谷盆地,形成于被动陆缘裂谷构造环境,具有SEDEx型铅锌矿床的地质特征,容矿岩性为一套巨厚的粉砂质、泥质碎屑岩建造,成矿作用与海相基性火山岩有关,矿体产状与地层走向一致,矿石具有明显的纹层状构造,在矿物共生组合上,表现为锌多铅少,不含铜,且闪锌矿为含铁较少的低温闪锌矿。     

桂西那弱银金矿床矿物组合特征及银和金的赋存状态研究

广西天峨那弱银金矿床以银矿为主,共/伴生金及铅、锌、锑等金属,矿物组合在右江盆地内为首次发现。矿体受那弱背斜及其轴向断层控制,赋矿层位为中三叠统百逢组含钙质浊积岩系。矿石矿物以硫锑铅矿、铁闪锌矿、黄铁矿、毒砂和方铅矿为主;脉石矿物主要有石英、方解石、绢云母等。主要矿石矿物由早到晚的生成顺序为:毒砂→黄铁矿→铁闪锌矿→硫锑铅矿→方铅矿。单矿物化学分析显示硫锑铅矿含Ag最高,其次为闪锌矿;黄铁矿含Au相对较高。EPMA测试结果表明Ag于方铅矿中含量最高,其次为硫锑铅矿;主要矿石矿物中毒砂含Au相对较高,其余矿物中Au含量均偏低。因矿石中的铅矿物主要为硫锑铅矿,可以认为那弱银金矿床的Ag主要赋存于硫锑铅矿中,Au主要赋存于毒砂与黄铁矿中,二者均以显微-次显微状态赋存于载体矿物中。根据矿物组合及其相互交代、切割关系等特征,将矿床划分为2个成矿期共4个成矿阶段。其中,第一成矿期为金的成矿期,矿物组合为黄铁矿和毒砂,由于后期成矿作用的叠加,仅保留一个成矿阶段;第二成矿期为银铅锌成矿期,矿物组合为方铅矿-闪锌矿-硫锑铅矿;包含第二至第四共3个完整的成矿阶段。该矿床Ag、Au共生是不同期次成矿作用叠加的结果。     

The Paleoproterozoic carbonate-hosted Pering Zn–Pb deposit, South Africa: I. Styles of brecciation and mineralization

The Pering deposit on the Ghaap Plateau, Northwestern Province, South Africa, was the largest of several Zn–Pb occurrences hosted by Neoarchean platform dolostones of the Transvaal Supergroup. With a Paleoproterozoic mineralization age, these occurrences are widely regarded as the oldest representatives of Mississippi Valley-type Pb–Zn deposits. Hosting an initial resource of 18 Mt at an average grade of 3.6 wt% Zn and 0.6 wt% Pb, the Pering deposit was mined from 1984 until its final closure at the end of November 2002. In this study, available geological and grade distribution maps were evaluated and complemented by the examination of mining-related outcrops, drill core, and a large set of ore and host rock samples. Four different styles of brecciation can be distinguished at the Pering deposit: (1) pyritic rock matrix breccia; (2) chemical wear breccia; (3) mosaic breccia; and (4) crackle breccia. Geological and mineral paragenetic observations on these different breccia types suggest that the formation of the Pering deposit commenced with an initial stage of hydrothermal karstification. Large volumes of pyritic rock matrix breccia formed by wall rock collapsing into the open space attributed to carbonate dissolution. This stage of hydrothermal karstification acted as ground preparation for the subsequent mineralization event. By the upward advance of the hydrothermal karstification process, fluid reservoirs in the previously undisturbed dolostone host rock succession were tapped, ultimately leading to fluid mixing. Hydrothermal sulphides are the most abundant where fluid mixing was most effective, i.e. along the outer and upper margins of the breccia bodies, and in stratabound zones along permeable host rock units. Chemical wear brecciation and formation of large volumes of fine-grained replacive sphalerite mineralization mark the early stage of hydrothermal Zn–Pb mineralization associated with this fluid mixing. The fine-grained stage of sulphide mineralization was succeeded by very coarse-grained open-space-infill mineralization. The latter is very uniform across the entire deposit and typically cements mosaic and crackle breccia, but also fills remaining open space within chemical wear brecciated portions of the deposit.     

Formation and age of sphalerite mineralization in carbonate rocks of Bajocian age in the Swiss Jura Mountains: evidence of Mesozoic hydrothermal activity

A combination of petrographic and geochemical techniques was applied to better constrain the origin and evolution of the fluid systems responsible for the formation of disseminated, Cd-rich (up to 0.6 wt%), sphalerite (ZnS) mineralization in the northeastern part of the Jura Mountains, Switzerland. The Rb–Sr ages of sphalerite samples indicate that a main phase of sphalerite formation occurred near the boundary between the late Middle and early Late Jurassic, at around 162 Ma. The negative δ³⁴S values (?22.3 to ?5.3 ‰) suggest that biogenic sulfide sulfur was involved in ZnS precipitation. The strontium isotope composition is more radiogenic than that of contemporaneous seawater, reflecting the interaction of mineralizing fluids with silicate rocks. Lead isotope signatures are very uniform (²⁰⁶Pb^/204Pb = 18.63–18.67, ²⁰⁷Pb^/204Pb = 15.63–15.64, ²⁰⁸Pb^/204Pb = 38.51–38.63), indicating an isotopically well-homogenized fluid system. The basement rocks underlying the Jurassic strata are considered to be the main source of metals for the sphalerite mineralization. The migration of deep-sourced hydrothermal saline metal-bearing fluids into the Bajocian host carbonates containing sedimentary reduced sulfur resulted in the precipitation of sulfides. The period of sphalerite formation near the Middle–Late Jurassic boundary is characterized by enhanced tectonic and hydrothermal activity in Europe, related to the opening of the Central Atlantic and tectonic/thermal subsidence during spreading of the Alpine Tethys. Our study provides evidence that the Bajocian carbonate rocks in the Jura Mountains area were affected by the circulation of deep-sourced metal-bearing hydrothermal fluids in response to these continent-wide tectonothermal events. The presence of sphalerite mineralization and associated geochemical anomalies in Zn and Cd contents in carbonate rocks may also be used to trace basement features.     

湖北凹子岗锌矿床Rb-Sr同位素测年及其地质意义

凹子岗锌矿床位于黄陵背斜东部,是近年来在湘西鄂西地区发现的代表性矿床。锌矿体呈似层状-透镜状产出,赋存于灯影组二段,含矿岩性为一套角砾状泥粉晶云岩,严格受地层层位及岩性控制。文章运用闪锌矿Rb-Sr同位素测年方法,测得凹子岗锌矿床成矿年龄为431~434 Ma,相当于早志留世,代表了矿床的主成矿阶段年龄。闪锌矿具有较高的Sr同位素初始比值(0.71119~0.71136),反映成矿物质或成矿流体由基底岩石和震旦系碳酸盐岩地层共同提供。凹子岗锌矿床早期成矿作用与早志留世的裂谷盆地伸展运动关系密切,晚期成矿作用与加里东运动关系密切,是伸展环境盆地流体运移的产物。加里期运动与黄陵周缘铅锌矿的成矿作用关系密切。凹子岗锌矿床成因类型为热液喀斯特成因,可分为深埋藏成岩成矿阶段和热液喀斯特化成矿阶段。     

兰坪盆地白秧坪铅锌铜银多金属矿床:成矿年代及区域成矿作用

针对沉积岩容矿铅锌矿床的定年难题,选用闪锌矿的Rb-Sr法和成矿阶段方解石的Sm-Nd法,对白秧坪铅锌铜银多金属矿床3个矿段(吴底厂、李子坪、富隆厂)分别测定,取得了较好的定年效果。测得白秧坪铅锌多金属矿床的铅锌成矿年龄为30~29Ma,而且3个矿段结果可互相印证。进而通过成矿年龄的探讨,认为矿区发生过2次矿化事件,一期为以铜为主的矿化,发生于古新世末-始新世初期,印度板块-欧亚板块强烈挤压后的应力松弛阶段成矿;另一期是以铅锌为主的矿化,发生于30~29Ma,对应于始新世末-渐新世早期挤压后应力松弛阶段。两期矿化事件在上千千米的"三江"成矿带上普遍存在,但在不同部位铅锌成矿时代略有不同,印度板块的东北角首先对接欧亚板块,位于岬角处正碰位置铅锌成矿要稍早于两侧的铅锌矿化事件。     

Volcanic stratigraphy, structural controls, and mineralization in the san cristobal Ag–Zn–Pb deposit, southern bolivia

The Late Miocene San Cristobal Ag–Zn–Pb deposit represents syngenetic and epigenetic mineralization with low- and high-sulfidation characteristics. Rocks in the deposit are characterized by barren dacitic ring fracture domes, mineralized resurgent rhyodacite domes, strongly altered and mineralized tuffaceous lacustrine sedimentary rocks, and an extensive crystal-lithic tuff debris apron. The ore body is hosted by intracauldron sedimentary and volcanic rocks and genetically associated breccias. Fluid inclusion data suggest that silver, lead, and zinc were transported as chloride complexes and precipitated by cooling in veins from <5 wt.% NaCl eq. fluids at 170–215 °C. Silver that was spatially, and perhaps temporally, associated with an episode of rhyodacite resurgence may have been transported as a chloride complex and precipitated by increased H₂S activity or increased fluid pH. Although San Cristobal represents a major silver resource, the occurrence of stratiform wurtzite and sphalerite in cauldron-hosted sedimentary rocks represents a syngenetic component of mineralization that is very rare in continental caldera-associated epithermal deposits, which contributes to San Cristobal's significance as a zinc resource.     

山东省平度市大庄子金矿区黄铁矿、方铅矿与金的共生关系研究

通过对山东省平度市大庄子金矿区黄铁矿、方铅矿三个蚀变阶段特征研究,发现金矿化主要发生在第二阶段,强烈的石英-黄铁矿-碳酸盐化与金矿化的关系最为密切。金多数以包体的形式赋存于黄铁矿等金属硫化物中,并且在黄铁矿、方铅矿、闪锌矿等矿物共同产出时更有利于金的富集。研究认为石英和黄铁矿组合以及黄铁矿、黄铜矿、方铅矿、闪锌矿的组合可作为金的富集指示性矿物组合,伴生矿物之中方铅矿含金性最好。方铅矿、黄铜矿、闪锌矿和磁黄铁矿呈细脉状、网脉状、斑杂状产于含金石英脉和团块状黄铁矿的裂隙中,研究发现细脉状较团块状黄铁矿含金性要好。