甘肃礼岷成矿带主要金矿床同位素地球化学特征对比分析

西秦岭礼岷成矿带具有良好的成矿地质条件,找矿潜力巨大。通过对该区域4个金矿床硫同位素、碳氧同位素、氢氧同位素、微量元素、稀土元素及流体包裹体对比,发现礼岷地区金矿床成矿物质主要来源于晚古生代沉积岩(主要为李坝群),成矿流体以大气降水为主,早期有部分岩浆水和变质水参与成矿。认为成矿于中低温弱矿化度、弱酸性、弱还原条件下。目前除中川岩体外,其他岩体周围也具备同样的成矿条件,本文旨在其他岩体周围取得金矿勘查的新成果提供借鉴。     

新疆西南天山金矿床主要类型、特征及成矿作用

文章在总结前人研究成果的基础上,综合论述了西南天山金矿的成矿地质背景、金矿床的时空分布和基本特征。根据矿床地质特征和控矿因素,将西南天山的金矿划分为与剪切带有关的金矿床、与侵入岩有关的金矿床(包括斑岩型)、石英-重晶石脉型金矿床、与火山岩有关的金矿床和矽卡岩型金矿床5类,其中与剪切带有关的金矿床是最重要的矿床类型。探讨了西南天山金矿的成矿时代、成矿物质和成矿流体来源,以及成矿地球动力学机制。提出与剪切带有关的金矿床成矿物质主要来源于岩浆和海相碳酸盐岩,成矿流体主要来源于岩浆水或主要来自大气降水,混合少量岩浆水。石英-重晶石脉型金矿床成矿物质来自容矿地层,成矿流体主要来源于沉积建造水。与剪切带有关的金矿、与侵入岩有关的金矿、石英重晶石脉型金矿和矽卡岩型金矿成矿时代主要集中在二叠纪—三叠纪,形成于后碰撞构造演化阶段。斑岩型和浅成低温热液型金矿床形成于岛弧挤压环境。     

甘肃阳山超大型热液金矿床的成矿特征

从阳山超大型金矿床的区域构造演化发展背景、成矿地质地球化学等特征进行的研究与分析表明,它是形成、产出在中新生代活化造山带、地壳高位浅成的中低温热液型超大型金矿床。从大地构造成矿学的研究途径,对其成矿流体与成矿物质的源区类型、形成与演化的构造环境、成矿作用的地质成因类型、成矿流体传输与聚集的构造系统等方面的初步研究表明成矿流体是变质与非变质的复杂混合体系,主要由基底、盖层中的构造热动力区域变质流体+重熔花岗岩浆热变质流体+岩浆热液等,组成多成因类型混合成矿流体,并受到同生水、大气降水的混染。因此,阳山金矿主要是由混合型变质成矿流体与岩浆热液成矿流体叠加形成,具有多因复成成矿特征的超大型中低温热液金矿床。     

吉南老岭成矿带荒沟山、板庙子金矿床地质特征与成因

以吉林东南部老岭成矿带中较具规模的荒沟山、板庙子金矿床为代表,对矿床地质特征进行对比,认为区内太古界表壳岩、晚元古界老岭群为主要矿源层,北东向深大断裂带为主要控矿构造,空间上金矿体的分布与岩浆岩关系不密切。结合区内成矿地质条件及成矿物质来源分析,认为金矿床形成于中低温热液环境,深部流体、岩浆热液及大气降水作为成矿流体共同参与了成矿作用,以大气降水为主,构成大气降水—深源热液循环成矿系统。老岭金及多金属成矿带具有较大的成矿潜力和良好的找矿远景,区内金矿的分布主要与大型断裂带相关联的珍珠门组大理岩上部不整合有关。     

湖南铲子坪金矿床地质特征及成因

湖南铲子坪金矿床位于雪峰弧形构造带西南段,是雪峰-金山巨型弧形推覆剪切金锑钨成矿带的重要组成部分,形成于碰撞或后碰撞地质背景下的走滑和逆冲构造事件中。文章通过总结前人系统的硫、铅、氧、氢同位素地球化学特征及成矿时代的研究,并进行了成矿流体特征的研究,在此基础上探讨了铲子坪金矿的成矿物质来源。研究结果显示,铲子坪金矿床矿石略富轻硫,具典型的岩浆硫+变质岩混合硫源特征,铅为壳幔混合铅,主要来自造山带。成矿期流体包裹体均一温度范围主要为140~220℃和260~300℃,盐度w(NaCleq.)范围主要为4%~10%和20%~24%,具有两个阶段成矿的特征,成矿流体为中低温、中低盐度、H2O-CO2-NaCl流体体系,存在流体沸腾现象,成矿流体主要来源于岩浆水,同时有大气降水的加入。成矿物质和成矿流体的来源为地层变质岩叠加印支期的岩浆作用。通过综合分析,初步认为铲子坪金矿床与造山型金矿相似,但具有一定特殊性。     

卡林型金矿床的特征和成因

卡林型金矿床主要分布在北美大盆地地区科迪勒拉造山带、科罗拉多地台和我国扬子地块西南缘的板内古生代－中生代沉降带和西北缘古生代－中生代冒地槽。具有分布局限、成矿集中的特点，形成许多超大型矿床。金矿床成矿域发育一套大面积分布的巨厚的古－中生代冒地槽建造，同成矿期的岩浆活动和构造活动强烈，有利于形成各种地热体系和流体活动。金矿床往往形成成矿带，单个金矿床的规模大小不一，矿化受构造、围岩和深部流体控制，围岩一般具有还原性质。围岩蚀变为去碳酸盐化、硅化、泥化、硫化物化和重晶石化等。金与砷黄铁矿、黄铁矿及毒砂紧密相关，以次显微金的形式存在。其他矿物为雄黄、雌黄、重晶石、辉锑矿、石英、方解石、含铊矿物以及表生矿物明矾石和黄钾铁矾等。成矿流体中水为大气降水，碳、硫主要来源于矿床围岩和以下岩石，少量可能来源于深部。矿床形成于浅－中等深度。提出了大气降水热液、岩浆热液、变质热液和卤水成矿等卡林型金矿床形成模式，大气降水成因模式能较好解释金矿床的地质地球化学特征。     

新疆北部浅成低温热液型金矿床成矿地球化学特征初探

产于晚古生代火山岩中的浅成低温热液型金矿床是新疆北部近期发现的一个重要的金成矿类型。通过对本区部分浅成低温热液型金矿的容矿火山岩岩石化学成分、ＲＥＥ分布模式、硫同位素、氢同位素、氧同位素和锶同位素及流体包裹体成分的分析与对比,讨论了其基本成矿地球化学特征,并揭示了本区浅成低温热液型金矿床与我国东部地区某些产于中生代陆相火山岩中的同类型金矿床在成矿地球化学特征上存在的一些差异。     

海南抱伦金矿床成矿时代研究

抱伦金矿床是海南省新近发现的大型金矿床之一，属于发育于下志留统陀烈组浅变质岩系中受断裂构造裂隙控制的岩浆热液型金矿床。成矿流体包裹体特征和氢氧同位素研究表明，成矿流体以岩浆水为主，有部分变质水的参与，大气降水影响比较小；成矿元素地球化学背景、硫同位素、稀土元素和初始锶比值等反映成矿物质来源虽然以变质岩为主，但有部分来源于岩浆岩；成矿物质和成矿流体来源反映出成矿作用与岩浆活动的密切关系。由热液蚀变矿物Rb-Sr等时线年龄234Ma和K－Ar年龄213Ma可知，金矿化年龄为210－230Ma，所以，抱化金矿床的成矿时代为印支期。这一结果与粤西－海南成矿带的成矿时代特征及特提斯构造演化特点相吻合。     

甘肃省肃北县鸡叫沟金矿床地球化学特征及成因探讨

鸡叫沟金矿床矿石及含矿岩系的稳定同位素、流体包裹体及稀土元素等地球化学研究表明,金矿床形成于碰撞造山运动后期的裂谷环境,成矿物质主要来自中基性、超基性火山岩,为低温、低盐、浅成的金矿床.硫来自岩浆硫.矿物质水主要来自大气降水,后期又萃取了岩浆水.矿床类型为与岩浆作用有关的浅成低温热液型.     

福建德化地区东洋浅成热液金矿床成矿作用与成因研究

为揭示福建德化东洋金矿床的成因,进行了矿床地质、流体包裹体和氢-氧、硫、铅同位素的系统研究。结果显示成矿流体接近于大气降水;硫元素具有深源硫的特征;铅同位素表明成矿物质来源于古老下地壳。综合研究结果表明该矿床的初始成矿流体为中高温、低密度、低盐度的岩浆热液,沸腾作用以及大气水混合是成矿物质卸载的主要因素,矿床成因属于与次火山岩岩浆作用有关的浅成热液低硫化型金矿床。     

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.     

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″.     

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.     

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。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.     

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.