Geology and structural features of vein-type lead and zinc deposits

The geological and structural position and localization conditions of the vein-type Pb-Zn deposits of the Sadon (North Ossetia) and East Karamazar (North Tajikistan) ore districts are considered. The leading role of long-lived deep faults in the control of large deposits is emphasized. Examples of such deposits in different provinces are given. The study of fractures and faults at Pb-Zn deposits is important for understanding of the formation conditions of other hydrothermal deposits.     

Geology of bogala mine,ceylon and the origin of vein-type graphite

The unique vein-type graphite deposits of Ceylon occur in high-grade metamorphic terrain of Early Precambrian metasedimentary series. At the Bogala graphite mine, the rocks are of the granulite and almandine amphibolite metamorphic facies. The direction of veins is strongly controlled by the two major regional lineation directions; veins with a third direction are also present. The veins are very irregular in length, width, and local attitude and contain only minor amounts of other minerals than pure graphite. Each vein is made up of a number of parallel graphite sheets oriented parallel to the vein. It is suggested that the Ceylon graphite veins, and possibly all similar deposits, form by lateral secretion. The graphite is obtained from the surrounding carbon-rich sediments and transported in the solid phase as the slippery graphite grains move along grain boundaries down a pressure gradient. The graphite accumulates along the relatively low-pressure zones of fractures. Each graphite sheet within the vein represents a period of pressure release along the fracture.

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Zusammenfassung Die einzigartigen gangförmigen Graphitlagerstätten von Ceylon befinden sich in einem hochgradig metamorphen Gebiet präkambrischer Sedimente. Die Bogala Grube liegt in einer Granulit- und Almandin-Amphibolitzone. Die Richtung der Gänge wird weitgehend bestimmt durch die beiden regionalen Gesteins-Hauptrichtungen; doch gibt es auch Gänge, die einer dritten Richtung folgen. Länge, Breite und lokaler Verlauf der Gänge sind sehr unregelmäßig. Neben reinem Graphit weisen sie nur geringe Mengen anderer Mineralien auf. Jeder einzelne Gang besteht aus einer Reihe gangparalleler Graphitzonen. Es besteht die Vermutung, daß die ceylonesischen Graphitgänge und möglicherweise alle ähnlichen Lagerstätten durch Lateralsekretion entstanden sind. Der Graphit stammt aus den stark karbonhaltigen Sedimenten der Umgebung und wird im festen Zustand umgelagert, indem die Graphitblättchen sich auf Korngrenzen in Richtung des Druckabfalls bewegen. Der Graphit sammelt sich entlang den Bruchzonen mit relativ niedrigem Druck an. Jedes Graphitband im Gang ist auf eine Druckentlastung entlang der Bruchzone zurückzuführen.

     

胶东脉型金矿定量统计模型

胶东存在中深成和浅成两类脉型金矿。定量统计模型研究发现，形成于 挤压地球动力学环境的中深成脉型金矿，成矿深度相对深，规模大，矿化强，形成于拉张地球动力学环境的浅成脉型金矿，成矿深度相对浅，规模小，矿化弱。     

Geology,geochemistry and age of a Cu-Mo-bearing granite at Kabeliai,southern Lithuania

Summary A Cu-Mo-bearing granitoid belonging to the concealed Precambrian crystalline basement of Lithuania has been dated by the U-Pb zircon method and investigated geochemically. chemically. The granitoid is located at Kabeliai in southernmost Lithuania and forms part of a granitoid complex recognized as the Marcinkonys batholith. The Kabeliai granite is composed of quartz, plagioclase, microcline and biotite and shows a granitic to adamellitic peralummous/metaluminous composition with dominantly I-type chemistry. U-Pb dating of zircon yields an age of 1505 ± 11 Ma, which is considered to reflect the crystallization age of the granite.The Kabeliai granite displays several similarities in terms of geological setting, chemistry and age with certain granitoids in northeastern Poland (Mazury complex) and northwestern Belorussia (Mostovsky, Kamensky and Vydgodsky plutons), which are considered rapakivi-like in the literature. It is, however, uncertain whether proper rapakivi granites really exist in these areas as none of these granitoids displays the common characteristics of rapakivi granites (A-type chemistry, wiborgitic textures, associated Sn-Be-Pb-Zn-Cu mineralizations). We speculate that the 1.4-1.5 Ga granites southeast of the Baltic Sea rather might be correlated with granites of comparable age and geochemical character in southwestern Sweden. Another possible alternative is that the granitoids in Lithuania may not be correlated with any part of the Fennoscandian Shield.Zusammenfassung Ein Cu-Mo-führender Granitoid, der zum präkambrischen, kristallinen Grundgebirge Litauens gehört, wurde mittels der U-Pb Methode an Zirkonen datiert und geochemisch untersucht. Der Granit repräsentiert einen Teil des Marcinkonys Batholithes, und tritt in Kabeliai, im südlichsten Litauen auf. Der Kabeliai Granit besteht aus Quarz, Plagioklas, Mikroklin und Biotit und zeigt adamellitische, peraluminöse/metaluminöse Zusammensetzung mit vorwiegend 1-Typ Charakter auf. U-Pb Datierung der Zirkone ergibt ein Alter von 1505 ± 11 Mio Jahren, das als Kristallisationsalter anzusehen ist.In seinem geologischen mit Granitoiden im nordöstlichen Polen (Mazury Komplex) und Grant Ånlichkeiten mit Granitoiden im nordöstlichen Polen (Mazury Komplex) und Grant Ånlichkeiten mit Granitoiden im nordöstlichen Polen (Mazury Komplex) und im nordwestlichen Weißrussland (Mostovsky, Kamensky und Vydgodsky Plutone), die in der Literatur als Rapakivi-ähnlich angesehen werden. Es ist jedoch unischer ob echte Rapakivi-Granite in diesen Regionen existieren. Keiner dieser Granite zeigt nämlich die für Rapakivi-Granite typischen Kennzeichen (A-Typ Chemie, Wiborgit Texturen, assoziierte Sn-Be-Pb-Zn-Cu-Mineralisationen). Wir vermuten, daß die 1.4 1.5 Mia Jahren alten Granite südöstlich der Ostsee eher mit Graniten ähnlichen Alters und von ähnlichem geochemischen Charakter im südwestlichen Schweden zu vergleichen sind. Eine weitere Alternative wäre, daß die Granitoide Litauens mit keinem Granit im Fennoskandischen Schild korreliert werden können.

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Geologie, Geochemie und Alter des Cu-Mo führenden granites von Kabeliai, südliches Litauen

     

柴达木盆地南缘祁漫塔格—鄂拉山地区斑岩-矽卡岩矿床地质

柴达木盆地南缘祁漫塔格-鄂拉山地区发育斑岩-矽卡岩型铜多金属矿床,成矿主元素为Cu、Mo、Pb、Zn,大部分矿床伴生Au、Ag。斑岩型和矽卡岩型矿（化）体共生于同一个矿区之中,是这类矿床的一个重要特点。与成矿有关的侵入体是印支期的中酸性小岩体,它们具有浅成_超浅成和高侵位等特点。斑岩-矽卡岩矿床的成岩年龄和成矿年龄一致,形成于中三叠世至晚三叠世。它们是东昆仑造山带晚碰撞造山阶段壳-幔作用（幔源岩浆底侵-岩浆混合）的产物,与东昆仑地区这一时期的矽卡岩型铁多金属矿床、热液脉状多金属矿床,以及造山型金矿床共同构成了一个矿床成矿系列。     

藏南地区错那洞钨锡多金属矿床地质特征及成因

前人尚未关注特提斯喜马拉雅铅锌金锑成矿带钨锡成矿问题.错那洞钨锡多金属矿床位于特提斯喜马拉雅东段,产于新发现的错那洞大型片麻岩穹隆构造之中.错那洞钨锡多金属矿床主要富集钨、锡、铍,伴生铜、铅、锌、铋、钼等,其矿化类型主要为矽卡岩型;此外,铍的矿化类型还有伟晶岩型.主要矿石矿物为白钨矿、锡石和硅铍石,含有少量的黄铜矿、方铅矿、闪锌矿、辉铋矿、辉钼矿等,翠砷铜铀矿、晶质铀矿和钍石的发现表明错那洞地区具铀矿成矿潜力.研究结果表明,错那洞钨锡多金属矿床可达到大型-超大型规模.较低的Zr含量、Zr/Hf和Nb/Ta比值表明错那洞大型片麻岩穹隆核部淡色花岗岩为高分异花岗岩;花岗岩具有富钛铁矿、贫磁铁矿特征,Fe₂O₃/FeO < 0.5,锆石Ce/Ce*平均值约为23,暗示错那洞淡色花岗岩为还原性花岗岩.具还原性的高分异花岗岩是错那洞钨锡多金属矿床形成的必要条件,而片麻岩穹隆构造是其空间分布的控制因素,由此认为错那洞钨锡多金属矿受片麻岩穹隆构造和淡色花岗岩的双重控制.      

石英脉型钨多金属矿床的扇状成矿实例及找矿模型

石英脉型钨矿床是中国数量最多的钨矿床类型,但保有储量消耗迅速,迫切需要创新找矿模型,指导找矿突破。文章结合二十余年的找矿实践,通过详细分析扇状成矿矿床实例,构建了石英脉型钨矿床新的找矿模型。该模型强调赋矿裂隙为岩浆动力成因,在花岗岩体顶部呈扇状分布型式,岩浆期后热液恰在裂隙张开时充填其中而形成扇状成矿系统;提出“就岩找矿”、“就矿找矿”、“就矿找岩”的地质、地球化学和地球物理标志,指导矿床尺度的勘查工程部署。截至目前,该模型已在广东禾尚田钨锡矿床、广西珊瑚钨锡矿床、广西社垌钨钼矿床、江西盘古山钨铋矿床等获得了验证,找矿成效显著。     

Kaolin deposits at Melthonnakkal and Pallipuram within Trivandrum block, southern India

The kaolin deposits at Melthonnakkal and Pallipuram mines form part of the Warkalli Formation belonging to the Tertiary sequence in southern Kerala and occur at the boundary between the Tertiary sequence and Precambrian granulite facies metapelites (khondalites). The sedimentary clays are composed mainly of kaolinite, quartz and gibbsite. XRD and SEM studies have revealed that kaolinite is well-crystallized variety and the platy crystals are scarcely broken in the sedimentary clays. These sedimentary kaolins are considered to have been formed by intense tropical weathering of the khondalites, and subsequently transported and deposited with high organic input into lakes near the weathering crust over the basement rock. Besides, the surficial parts of the sedimentary deposits are extensively lateritized with the formation of goethite and hematite by Quaternary tropical weathering processes.     

比较行星地质学的研究方法、现状和展望

比较行星地质学是人类认识自然和人类本身形成与演化的前缘学科,是实现太阳系探测三大科学目标的主要手段.比较行星地质学研究主要回答3个问题:行星的现状是什么样的?行星的过去是什么样的?行星的过去、现在与太阳系其他行星的可比性如何?行星地质学的研究内容与研究地球地质相似,即撞击作用、火山(岩浆)作用、构造作用和夷平作用等,这些是塑造行星地貌最主要的地质作用,其中撞击构造是其他行星更为常见的地质作用.行星地质学的研究方法是利用遥感获得的各种影像、光波和电磁波等数据,以及在行星表面直接勘察获得的数据和取回的样品,对行星表面和地表以下的成分、结构和形成与演化过程进行研究.我国积极参与深空探测将获得第一手行星地质数据,国际深空探测计划的持续实施和数据的广泛共享为中国科学家积极参与行星地质学和比较行星学的研究提供了广阔空间,同时也为研究和认识地球提供新的和更全面的视野.     

兰坪盆地科登涧脉状铜矿床地质、地球化学特征

兰坪盆地西缘发育一系列脉状铜矿床,科登涧铜矿床是其组成之一。该矿床矿体主要产出于上三叠统崔依比组(T3c)中基性火山岩内部的断层破碎带中。热液期成矿作用可大致划分为2个成矿阶段:主成矿阶段主要发育大量含铜硫化物石英脉,晚成矿阶段主要发育贫硫化物方解石脉。流体包裹体结果表明,主成矿期石英和成矿后期石英/方解石中均主要发育两相水溶液包裹体,含CO2包裹体极少出现。主成矿期石英脉中包裹体均一温度变化幅度较小,集中在180~240℃,盐度(Na Cleq,质量分数)集中在8%~14%。成矿流体主要表现出盆地热卤水的特征,这与兰坪盆地内其它Pb、Zn、Cu等贱金属矿床的成矿流体特征较为一致。成矿流体的δ18O值为3.5‰~5.5‰,δD值为-62‰~-38‰,介于岩浆水/变质水和大气降水之间。热液硫化物黄铜矿、黄铁矿、斑铜矿的δ34S值显示较低的负值(-20.8‰~-9.4‰),明显有别于赋矿围岩(安山岩)的δ34S值(11.1‰~11.6‰),推测该矿床成矿所需还原硫主要来自于地层硫酸盐。综合分析认为,该矿床成矿物质主要来源于地层,成矿流体主要为源于大气降水或建造水的盆地热卤水。     

Chemical compositions of tourmaline in the vein-type tungsten deposits of the kaneuchi mine,Japan

Chemical compositions of tourmaline from the vein-type tungsten deposits of the Kaneuchi mine in Japan are obtained with an electron probe microanalyzer. Tourmaline occurring at this mine belongs to the dravite-schorl series. Magnesium contents are high compared with tourmaline from granitic zones. This suggests that ore-forming solutions are not formed directly from magmatic fluid and reacted with sedimentary rocks. Compositions of tourmaline in quartz veins are similar to those in host rocks, and the bulk compositions of host rocks do not indicate magnesium metasomatic reactions. It can therefore be concluded that water/rock interactions occurred at a deeper level which remains unexplored.     

城市地质学发展前景展望

本文介绍了城市地质学的定义和研究内容,对国外、国内城市地质学发展历史进行了述评,对城市地质学的发展前景进行了展望。     

Lateglacial environmental changes recorded in calcareous gyttja deposits at Gulickshof, southern Netherlands

Environmental changes were reconstructed from Lateglacial calcareous gyttja deposits at Gulickshof, southern Netherlands. Analyses of pollen, fresh-water mollusca, stable isotopes and geo-chemistry were performed and the combined evidence was put into a chronostratigraphic framework based on regional biostratigraphy and accelerator mass spectrometry radiocarbon dating. The pollen diagram showed vegetation development from the Bφlling interstadial into the Late Dryas stadial within 2.9 m of lacustrine deposits. Early in the Allerφd, around 11 900 BP, the composition of aquatic taxa and stable isotopes of calcium carbonate changed significantly. It appears that the final melting of relic ground-ice and subsequent re-establishment of the hydrological cell early in the Allerφd were responsible for these changes. Later in the Allerφd, around 11 250 BP, the disappearance of molluscs, changes in vegetation and isotope composition all point to colder climate conditions attributable to the Gerzensee oscillation. The combination of different lines of evidence in these types of deposits proves to be an excellent tool for unravelling climate and environmental signals.     

论石英脉型与矽卡岩型钨矿床成矿流体的差异性

石英脉型与矽卡岩型是最重要的两类钨矿床,二者间存在密切的成因联系,均经历了同源碱长花岗岩岩浆分异演化至晚期形成的浆液过渡态流体,进而演化至热液阶段,但二者成矿地质特征不同,成矿流体的差异性明显。通过对湖南瑶岗仙石英脉型钨矿与杮竹园矽卡岩型钨锡多金属矿的对比性研究,发现这种差异性自岩浆晚期阶段就开始了,热液阶段差异性更加显著。脉型钨矿成矿物质和成矿流体具有较单一岩浆来源,无明显外来流体的加入。与花岗岩相比,云英岩中的熔流包裹体气液部分含量更高,逐渐向流体包裹体演化。钨矿化石英脉的流体包裹体均一温度主要集中于350~150℃,盐度2%~8%NaC leqv,变化范围小;流体富CO2,Na+/K+1,成矿环境偏酸性。除岩浆至热液演化过程外,热液阶段的演化进程不明显,没有经历明显的沸腾和系统的降温过程。包括花岗岩、蚀变岩、石英脉等,石英的δ18O值相似,成矿体系的水/岩比值较低。矽卡岩型钨矿的成矿花岗岩浆受碳酸盐岩同化混染的影响,Ca、S含量增高。与多成矿阶段相对应,成矿流体温度、盐度跨度大,均一温度550~100℃,盐度35%~2%NaC leqv。岩浆晚期阶段及矽卡岩阶段,发生于岩浆固结之前大规模隐爆作用,引起成矿流体的沸腾,进而导致流体的高盐度、低CO2、Na+/K+1。CO2的逸失提高了体系的pH值,弱碱性环境下发生广泛钾长石化,流体属岩浆水性质。退变质氧化物阶段,均一温度450~250℃,盐度15%NaC leqv,大气降水参与成矿体系导致温度、盐度迅速降低。流体中高度富含Ca2+,是导致大规模白钨矿沉淀富集的主要机制。硫化物阶段,均一温度250℃,盐度10%NaC leqv,成矿流体中来自大气降水比例进一步增加,导致温度、盐度进一步降低,成矿环境向弱酸性转变。引起两类钨矿成矿流体差异性的主要原因包括:岩浆性质略有不同;沉积岩围岩尤其是碳酸盐岩的影响;隐爆作用的剧烈程度不同。     

Geology of the Chiltern Chalk aquifer,southern England

The unique geological history which resulted in the evolution of the Chiltern Hills to the north of London, The United Kingdom, created the underlying foundations for everything that we see there on the surface today. The roots of the Chiltern Hills lie in their Chalk foundations. To understand the details of the way the chalk acts as an aquifer it is important to understand first the origins of the chalk sediment and how the subsequent geological history of the region has impacted on the rocks preserved today.     

福建永安丰门坑多金属矿地质特征及找矿前景

永安丰门坑多金属矿呈似层状、层状、透镜状,贮存在寒武系林田组下段钙质碎屑岩中,矿床具明显的层控和热液叠加改造特征,为沉积-热液改造型多金属矿床。该多金属矿床的发现,为我省在寒武系林田组中寻找该类矿床提供新的目标。     

内蒙古东七一山钨锡多金属矿成矿特征与控矿因素分析

内蒙古东七一山钨锡多金属矿是北山地区成矿地质特征复杂且具代表性矿床之一。在综合分析区域大地构造与成矿、地层序列、复式杂岩体的前提下,并基于同北山、东天山、南岭类似矿床的对比分析,本文对该矿床的地质特征和控矿因素进行了研究。结果表明:该矿床是产在复式杂岩体内的以钨、锡、铷、萤石为主,伴生钼、铍、铁和铜的多金属-非金属矿床,矿脉群具备一定的内部结构型式。矿化具一定分带性,并与特定的蚀变对应。富W、Sn、Mo的区域地球化学场决定东七一山地区具备成矿的物质条件,成矿作用过程中,前寒武纪基底地层提供了矿源,泥盆纪碰撞造山使地层重熔形成含矿岩浆,岩浆热液在不同序次构造的控制下运移并析出矿质,并最终在有利的物理化学空间富集成矿。有关该矿床地质特征和控矿因素的分析有利于推动对整个北山地区钨成矿作用的认识和相关找矿工作的深入。     

Ages and geochemistry of Laojunshan granites in southeastern Yunnan, China: implications for W-Sn polymetallic ore deposits

The Southeastern Yunnan region is one of the most important polymetallic ore districts in South China. Located in the southern margin of the South China Block, these ore districts are part of a wider granite-related magmatic-hydrothermal system. Laojunshan granite intrusions, located in the western part of the Southeastern Yunnan, are closely related to W-Sn mineralisation. In this paper we report zircon U-Pb ages, geochemical and petrological characteristics for the ore-related granites in Laojunshan area. Three samples from three intrusive suites of the granitic rocks in Laojunshan intrusion have been analyzed by the LA-ICPMS zircon U-Pb techniques, yielding ages of 86.66?±?0.42 Ma, 86.72?±?0.47 Ma and 86.02?±?0.48 Ma, respectively. Bulk analysis reveals that three intrusive suites are strongly-peraluminous, silica-rich, aluminum-rich and alkali-rich granites and their ACNK values fall mainly into a small range of 1.10–1.38. Moreover, all granites show enriched Rb, La and Zr and depleted Ba, Sr and Ti, as well as a uniformly flat REE-pattern with a marked negative Eu anomaly. The granites and polymetallic W–Sn mineralization possibly both occurred during the Late Coniacian.