广东庞西洞银矿床的地球化学研究

通过矿床地质、矿物包裹体及向位素地球化学研究确定庞西洞银矿受韧性-脆性剪切构造带控制,成矿与燕山期同熔型花岗岩有关。矿床围岩蚀变钾化、黄铁绢英岩化强烈。成矿流体K~+>Ca~(2+)>Na~+>Mg~(2+);SO_4~(2-)>Cl->HCO_3->F-;CO>>CO_2>CH_4。流体低盐度(2.2wt％～4wt％NaCI)、弱酸性(pn为4.6)、密度0.81。成矿温度270℃,压力700×10~5Pa,fo_2=10(-39)～10~(-41),fs_3=10~(-12)～10~(-15),为中深中温岩浆热液银矿床。这类矿床是我国银矿新类型,许多方面与焦家式破碎带蚀变岩型金矿成矿特征相似,在粤西、桂东极具远景。     

粤西河台金矿锆石SHRIMP年龄及其地质意义

河台金矿是一个受剪切带控制的金矿床,成矿作用分为韧性剪切变质成矿期的韧性剪切变质成矿作用阶段和热液蚀变成矿期的金硅化石英脉阶段、金硫化物阶段以及方铅矿闪锌矿碳酸盐脉阶段,金的成矿主要发生在热液蚀变成矿期的金石英脉阶段和金硫化物阶段。SHRIMP锆石U-Pb测年显示赋矿围岩混合岩中继承性锆石的核部和幔部年龄为343.9~1732Ma,代表形成混合岩原岩的源区岩石的年龄;继承性锆石边部和混合岩化变质作用中新生锆石的年龄平均值为239.6±3.9Ma,属印支期,为混合岩化变质作用的年龄,这一年龄与印支期印支板块与扬子板块、扬子板块与华北板块的碰撞时代相一致,证实在中国华南存在印支期的混合岩化变质作用。韧性剪切变质成矿作用的年龄小于混合岩化变质作用的年龄(239.6±3.9Ma);富硫化物含金石英脉中热液锆石普通铅含量高,为0.65%~2.27%,Th/U值变化围很小,为0.306~0.557,其年龄为152.5±3.1Ma,属燕山期,代表河台金矿主成矿期年龄。     

湖南西部钨锑金矿床成矿规律及找矿应用

湖南西部钨锑金矿床赋存于雪峰弧形构造带之前寒武系浅变质岩系中,受到韧-脆性剪切构造控制,具有明显的地层层位效应。区域变质和动力变形过程中,大规模深层次的韧性剪切变形促使矿源层中的Au活化迁移,连同SiO2,K等活性组分和岩石中的H2O一起形成含金动力变质热液,当其进入伸展型脆韧性剪切带及其剥离构造带、张扭性断裂带时,形成充填交代型含金石英脉型和破碎带蚀变岩型金矿。研究表明,矿床具有特定的元素共生组合,矿脉(体)沿倾向延伸大且普遍具有侧伏成矿现象,沿控矿构造方向侵入的长英质脉岩带与成矿有一定的联系;载金的硫(砷)化物以富集轻硫同位素为特点,氧化-还原反应是金成矿的主要化学机制等特征性成矿标志。矿床广泛发育中低温热液蚀变,黄铁矿、毒砂矿物和As元素是找金的标型矿物和指示元素。矿床成因主要属于受韧-脆性脆剪切带控制的变质热液型金矿。     

广东河台金矿硫化物地球化学特征及地质意义

河台金矿是广东省最大的金矿, 被认为是典型的剪切带型金矿。尽管矿床产于云开群变质岩中, 但是在产出时间和空间展布上又与云楼岗和伍村岩体有密切关系, 再加上成矿的多阶段性, 导致对成矿流体及物质来源一直存在争议。河台金矿的金主要以自然金形式产出, 与黄铁矿、黄铜矿、磁黄铁矿等矿石矿物紧密共生。本文对河台金矿田热液成矿期金-硫化物阶段的黄铁矿、磁黄铁矿进行了微量元素和Sr-Nd同位素分析, 以进一步示踪成矿流体及物质来源。两种硫化物Co/Ni比值为0.36~3.33, 显示主要为热液成因。Hf/Sm、Nb/La、Th/La值<1, 暗示成矿热液是以富Cl–的流体为主; Y/Ho比值为12.0~33.0, 与糜棱岩有明显区别; (87Sr/86Sr)i值为0.707 078~0.713 545, εNd(t)为–19.36 ~ –15.12, 位于华夏板块元古代基底和EM1富集地幔之间。这些特征暗示成矿流体的多源性。黄铁矿∑LREE/∑HREE值介于5.53~15.4, 在球粒陨石标准化图中呈明显右倾, δEu值为0.48~0.75, 具有明显的Eu负异常, 与糜棱岩特征相似, 暗示成矿物质主要来自围岩。结合前人年代学研究结果, 推测印支期在混合岩化和韧性剪切作用下, 变质流体将云开群中的成矿物质运移到剪切带中, 使Au初步富集; 燕山期地壳深部华夏板块中—古元古代基底重熔产生的岩浆流体混入少量地幔流体, 为剪切带中成矿物质发生活化迁移提供载体和动力, 并在局部再次富集形成工业矿体。     

广西五圩矿田箭猪坡铅锌锑多金属矿床成矿流体特征及特富矿体形成分析

箭猪坡矿床是广西丹池成矿带南段五圩矿田中最大的Pb-Zn-Sb多金属矿床。矿床主要由早阶段特富大脉状闪锌矿-脆硫锑铅矿矿化和晚阶段脆硫锑铅矿-闪锌矿-碳酸盐-石英脉状矿化组成。本文分析了箭猪坡矿床两种不同矿化类型石英、闪锌矿中的流体包裹体特征、均一温度及盐度,探讨特富矿体形成的控制因素。两种矿化类型包裹体主要由含CO_2包裹体和水溶液包裹体组成。早阶段特富大脉状矿化流体包裹体均一温度为120~290℃,集中在220~290℃之间,盐度为3.6%~13.6%。晚阶段脉状矿化流体包裹体均一温度为150~350℃,集中在240~310℃之间,盐度为1.4%~12.0%。富CO_2成矿流体主要来自变质、有机质中低温热降解、有机质还原、岩浆出溶及夕卡岩化。箭猪坡矿化产于泥盆系破碎带中,晚于华南地区变质作用;矿床成矿温度(220~310℃)远大于有机物热降解释放大量CO_2的温度(约150℃);矿床深部发育Sn矿化,表明成矿流体具还原性,不太可能含有大量而区内非夕卡岩化岩浆热液矿床成矿热液只含有少量CO_2。因此,初步认为箭猪坡矿床富CO_2流体主要与深部夕卡岩化作用有关,成矿流体主要来源于岩浆热液。成矿流体含少量甲烷、沥青质等有机质,表明成矿过程有盆地卤水混入。早阶段特富矿体成矿流体在温度–盐度图上显示中高温中高盐度和低温低盐度流体混合特征,而晚阶段脉状矿化成矿流体温度–盐度分布较为分散,暗示晚阶段脉状矿化成矿过程主要经历了冷却降温,流体混合较弱。这表明成矿流体大规模混合是形成特富矿体的关键控制因素。依据富CO_2流体可能主要来源于深部夕卡岩化作用,初步推测五圩矿田深部有寻找夕卡岩型矿床良好前景。     

滇中龙岗地区多金属矿带成矿地质特征及找矿方向

文章总结了滇中龙岗地区金、铜、铁、铅-锌、银等多金属矿床的类型和成矿规律,指出该区成矿演化有4个时期:早元古代铁-铜成矿期,中元古代-中三叠世古风化壳铁(金)矿成矿期,燕山期-早喜马拉雅期金、铅-锌(银)成矿期,晚喜马拉雅期金成矿期;相应地在空间上自下而上形成了4种成因类型的矿床组合:海相火山喷发-沉积-变质铁-铜矿床,古风化壳型铁(金)矿床,构造破碎带热液蚀变脉状金矿床和铅-锌(银)矿床,沉积-热液改造砂砾岩型金矿床。文章指出了该区找矿主攻矿种和有利找矿地段。     

上宫金矿地质地球化学特征和成矿模式

上宫金矿产于豫西熊耳山的熊耳群内,属蚀变破碎带型金矿。矿床具有成矿物质、成矿热液多来源和成矿过程多期多阶段的特征。从早到晚,成矿热液性质由变质热液(中高温)、混合热液(中温)演化为大气降水热液。矿床形成于中生代,是沿马超营断裂向北的陆内俯冲作用的结果,可用陆内俯冲成岩成矿模式指导找矿。     

新洲金矿床的地质特征及其成因

广东新洲金矿床产于褶皱式推覆构造外来系统——震旦系乐昌峡群变质地层之中.金矿床主要属碎裂石英脉型,次为蚀变糜棱岩型.成矿作用早期形成糜棱岩型金矿,为韧性剪切成矿期;晚期形成碎裂石英脉型金矿、属韧-脆性和脆性成矿期.成矿溶液为浅成中低温变质-混合岩化热液,成矿物质来源于震旦系,属褶皱式逆冲推覆-剪切带型金矿床.     

新疆多拉金矿床成因探讨

从金矿的成矿环境、矿床特征、矿石矿物特点、控矿构造——韧性剪切带特点、同位素特征、流体包裹体特征及黄铁矿化学成分提供的成因信息等,探索多拉金矿的容矿控矿因素、矿质来源和矿液性质,揭示多拉金矿的成因:是受韧性剪切带控制的中低温岩浆热液-变质热液矿床。     

粤西河台金矿床富硫化物含金石英脉锆石U-Pb 测年及成矿意义

河台金矿是一个强烈受韧性剪切带控制的金矿床,金的成矿主要发生在热液蚀变成矿期的金石英脉阶段和金硫化物阶段,形成的矿石有蚀变糜棱岩型和富硫化物石英脉型.富硫化物含金石英脉中单颗粒锆石U-Pb同位素测年显示早加里东期是河台金矿床主成矿期,成矿年龄为492±16Ma;矿区燕山期伍村花岗岩的单颗粒锆石年龄为153.6±2.1Ma;结合已有的同位素资料,认为河台金矿床是华南加里东期构造-变质-岩浆作用及成矿作用的一个组成部分,是一个早加里东期造山作用同期的造山带型金矿床,并可能有燕山期的热液叠加成矿作用.     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Global repeating events in the history of the Earth and the motion of the Sun in the Galaxy

Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返

位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压，而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩，榴辉岩及其他直接围岩皆呈包体存在于其中，并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体，表明新元古代花岗岩的组成物质也经受过超高压变质作用，且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次（或阶段）却少于榴辉岩。椐上述可得如下推断：超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部（俯冲板块前部）形成的；榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的，其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升，遭受剥蚀。     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。     

摩擦桩基桩土间极限摩阻力取值问题探讨

通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。     

Paleomagnetic implications on the evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic

We first re-examined the apparent polar wander curves for stable Eurasia and Africa since the Triassic. These curves were then combined together with curves of North and South America according to the kinematics of the Atlantic ocean and a synthetic polar wander curve was given. Then, most of the paleomagnetic results from the Tethys mobile belt, from the Atlantic to the Pamirs, were analysed.Several groups of plates, microplates and blocks can be seen. First, relatively stable regions like Maghreb and Sicily, which have not moved much. Then we have a group formed by Iberia, Sardinia, Italy and, to a lesser extent, Corsica and the Western and Central Alps. For these blocks, movements are anticlockwise rotations chiefly driven by the anticlockwise rotation of Africa, but they are sometimes stronger.To the east, a major change takes place. The north of the Aegean Sea and the Ionian zone are clockwise rotated and these rotations are recent: Oligocene-Miocene for the first part, Pliocene to the present for the second part.A major problem arises in Turkey, Caucasus and Iran. Paleomagnetic results indicate a position far to the south of Eurasia, and, at the same time, geological evidence is in favour of a position close to Eurasia. We discuss these discrepancies.     

On the consistency of proposed models for the Pyrenees with the structure of the eastern parts of the belt

The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time.