扬子地台东南缘黑色岩系(荷塘组)地球化学研究

扬子地台东南缘下寒武统荷塘组地层代表性剖面,主要由碳质硅度泥岩及硅质岩类石煤层组成,黑色岩系则分布于底部,岩石为层状,岩性为磷块岩或含磷结核硅质岩,其稀土元素在含钼钒高碳泥岩中富集,稀土总量达233.43×10-6~258.95×10-6,其他岩层的稀土元素总量在89.15×10-6~144.70×10-6之间;相对富轻稀土,轻重稀土、轻稀土分馏作用明显,重稀土分馏作用不明显;铕、铈负异常(δEu值0.55~0.71,δCe值0.46~0.88,(La/Yb)N平均值4.65~10.89;(La/Sm)N平均值9.55~18.44,(Gd/Lu)N平均值0.91~1.67)。沉积的构造环境为被动的大陆边缘,沉积环境为干燥气候的还原环境,不同的古地理条件或海平面的升降,造成了稀土元素特征的差异。     

重庆城口地区下寒武统黑色岩系元素地球化学特征及其成因

地区广泛发育有下寒武统。利用ICP-MS方法系统分析重庆城口地区下寒武统黑色岩系中多金属富集层、炭质粉砂岩以及硅质岩样品的微量元素、稀土元素组成。研究结果表明稀土总量为111.41×10-6~184.13×10-6,平均为138.83×10-6,相对其他地区黑色岩系较低;LREE/HREE=2.49~3.44,LREE相对富集,HREE亏损;δCe=0.39~0.46,Ce呈明显负异常;δEu=0.84~1.10,Eu异常不明显。δCe,δU,V/Cr,Ni/Cr,V/(V+Ni)表明该区黑色岩系形成于缺氧环境;稀土元素地球化学特征及其相关图解、Cr,Sb,As,Bi的富集以及U/Th等反映本区黑色岩系非正常海水沉积产物,明显受热水沉积的影响,同时还存在火山活动的影响,火山活动可能为热水活动提供了动力及物质成分。     

湘西下寒武统牛蹄塘组地球化学特征及其对沉积-构造环境的响应

为深入探讨湘西地区下寒武统牛蹄塘组黑色岩系沉积-构造环境,对三岔剖面黑色岩系进行了详细采样测试,并重点分析了主量、微量及稀土元素地球化学特征。研究结果表明,牛蹄塘组黑色岩系不仅有机碳含量高,而且相比于北美页岩更富集V、Ni、Cr等微量元素。δ~(13)C_(org)及微量元素判别指标V/(V+Ni)、V/Cr、Ni/Co、δU、Ce/La、Ce_(anom)等特征的变化均反映牛蹄塘组沉积期水体属缺氧还原的浅水环境,且Mo/TOC与U_(EF)-Mo_(EF)协同模式表明沉积区当时为一局限海盆环境。稀土元素(REE)中轻稀土相对重稀土富集,且北美页岩标准化分布模式呈近水平略微左倾状,结合元素比值特征和La/YbCe/Yb、La/Yb-ΣREE图解,牛蹄塘组黑色岩系的母岩以长英质岩石为主,但沉积过程也受到海底热液作用影响。同时,根据δCe、δEu的特征与K_2O/Na_2O-SiO_2图解,认为沉积区在早寒武世为被动大陆边缘构造背景。     

勉略构造带硅质岩元素地球化学特征及其形成环境

勉略构造带古生代硅质岩发育,其对西秦岭造山带古生代沉积环境与构造背景具有重要指示意义。本文研究了勉略构造带西段文县地区泥盆纪硅质岩的野外露头产状、岩石学与矿物学及全岩主微量元素地球化学特征,对比分析了该带东段硅质岩性质,综合剖析了勉略构造带古生代硅质岩的沉积环境,探讨了西秦岭造山带古生代岩相古地理环境及大地构造背景。文县硅质岩有灰白色块状硅质岩和灰黑色角砾状硅质岩两种类型,两者均具层状、条带状等沉积构造,并与上覆、下伏地层整合接触,为典型热水沉积硅质岩。岩石主要组成矿物为细晶-微晶石英,含有少量的方解石、绢云母及泥质等。岩石地球化学分析显示,硅质岩SiO2含量较高,为84.85%~99.07%,平均为91.99%,且灰白色硅质岩质地更纯,SiO2含量明显高于灰黑色硅质岩。硅质岩主微量、稀土元素Fe2O3/TiO2-Al2O3/(Al2O3+Fe2O3)、V/Y-Ti/V及LaN/CeN-Al2O3/(Al2O3+Fe2O3)图解表明该区硅质岩主要形成于大陆边缘及近大陆边缘环境。稀土元素显示灰黑色角砾状硅质岩稀土总量较高,为171.3×10-6~236.1×10-6,而灰白色块状硅质岩仅为11.96×10-6~51.06×10-6,表明前者所含陆源物质组分更多;稀土元素北美页岩标准化后两者整体显示了相似的轻重稀土分异不明显的平坦型稀土配分模式,其中灰黑色硅质岩δCe为0.95~1.05、δEu为0.66~0.87、(La/Yb)SN值为0.95~1.10,反映基本无Ce异常、弱Eu负异常及轻重稀土分异不明显;灰白色硅质岩的δCe为1.07~1.12、δEu为0.70~0.90、(La/Yb)SN值为1.64~4.07显示了弱Ce正异常、弱Eu负异常及弱轻重稀土分异,两者稀土元素特征与世界典型大陆边缘(裂陷)盆地硅质岩相近。文县硅质岩地质、元素地球化学特征表明其整体形成于大陆边缘及近大陆边缘沉积环境,但相比于灰白色块状硅质岩,灰黑色角砾状硅质岩有更多陆源物质加入。结合勉略构造带东段古生代硅质岩野外产出及地球化学特征分析,该区在早古生代-晚古生代早期主要处于扬子板块北部大陆边缘海盆沉积环境,有较多的陆源物质加入到富硅的热水沉积中,在勉略构造带内自西向东形成了一系列不同时代的热水沉积硅质岩。与此同时,西秦岭主要处于大陆裂陷构造背景之中,多期次的裂陷活动形成了一系列裂陷盆地及深大断裂,这对西秦岭古生代热水沉积硅质岩的形成具有重要意义。     

北秦岭庙湾组黑色岩系稀土元素地球化学特征及成因意义

笔者采用等离子质谱仪(ICP-MS)方法对北秦岭大荆区奥陶纪—志留纪庙湾组黑色岩系岩石的稀土元素及V、Ni、Cr、U、Th等微量元素含量进行了测定。结果显示岩石轻稀土元素相对重稀土元素富集, Eu异常值δEu为0.63~10.61(绝多数大于1.54)多呈正异常, Ce异常值δCe为0.65~1.02(平均为0.893) 异常微弱且有正负差异; U/Th值为0.38~4.07, w (V)/w (V +Ni)值为0.38~0.93以及w (Ce)/w (La)值为1.27~2.17。将这些特征值与前人研究成果对比, 并利用La/Yb-Ce/La和La/Yb-REE判别图解判别后, 认为北秦岭区庙湾组黑色岩系形成于活动陆缘一种干燥缺氧较深浅海环境, 黑色岩系形成过程中有热液作用参与。     

华北燕山东段下马岭组黑色岩系元素地球化学组成——对其沉积作用的约束

华北地区燕山东段下马岭组地层中发育一套黑色岩系,本文测定了该岩系代表性岩石的地球化学组成。主微量元素分析结果显示,样品主量元素含量变化较大(如SiO2=53.00%~78.83%,Al2O3=1.20%~17.57%);PAAS标准化稀土配分型式为重稀土富集型,具Ce负异常,与现代海水配分型式一致。样品具有较高的Al2O3+TiO2含量(1.31%~18.48%),其U含量(平均3.95×10-6)、Th/Sc值(0.97~1.26)、Th/U值(平均3.50)、球粒陨石标准化稀土配分型式及大陆地壳标准化微量元素蛛网图表明黑色岩系沉积过程中有较多陆源碎屑物质的加入。黑色岩系Ba/Sr值(9.28~22.79)、Co/Zn值(0.01~0.29)及相关图解显示其沉积过程明显受到海底热液作用的影响,但原始溶液中热液组分含量不足0.1%。主微量元素比值、Ce/Ce*PAAS值(0.82~0.93)及构造背景判别图解表明黑色岩系可能沉积于大陆岛弧背景下的深水缺氧环境。     

沙特北部恩乌尔磷矿床磷块岩地球化学特征 及沉积古环境分析

对沙特北部恩乌尔(Umm Wu'al)磷矿的磷块岩的常量、微量和稀土元素地球化学特征进行分析研究,探讨矿区内Arqah磷矿段中磷块岩的沉积古环境。分析结果表明,区内磷块岩主要由内碎屑、少量陆源碎屑、生物碎屑和填隙物等组成,以富含CaO、P_2O_5,少MgO、SiO_2为特点。磷块岩中Ba含量高达350×10~(-6),Sr含量高达1433×10~(-6),表明磷块岩成矿与生物作用关系密切。磷块岩Sr/Ba比值1.96～21.20,反映出其是为正常沉积的,而U/Th比值2.83～21.83,均大于1,则反映出成矿过程中有热水作用参与。δU为1.79～2.0,均大于1,表明磷块岩形成于明显的缺氧沉积环境。磷块岩稀土总量较高(平均150×10~(-6)),经北美页岩标准化的稀土配分模式曲线呈现近乎水平,轻重稀土分异程度低,轻稀土相对亏损,重稀土富集的特征。LREE/HREE比值0.63～2.08,绝大多数大于1,(La/Yb)_N平均为1.14,接近1,显示出磷块岩总体成矿古地理环境变化不明显,局部时段受海平面升降有所变化。δCe平均为0.28,小于1,负异常显著,进一步表明磷块岩形成于明显的缺氧的沉积环境。δEu平均为0.91,接近1,综合分析认为该区磷块岩形成于远岸的古地理变化不明显的缺氧沉积环境。     

重庆秀山小茶园大塘坡组含锰岩系地球化学特征及地质意义

本文根据矿石特征和岩石地球化学特征分析了重庆秀山小茶园一带锰矿床含锰岩系的物质来源、沉积环境和成因。该含锰岩系赋存于南华系大塘坡组一段。元素地球化学特征表明,主成矿元素Mn与Al_2O_3、SiO_2呈明显负相关,与MgO、CaO呈明显正相关,Ag、As、Sb平均含量明显偏高,显示研究区含锰岩系为热水沉积成因;Co/Zn-(Co+Ni+Cu)图解、(Co+Ni+Mn)×10-Fe-Mn图解和Y×P_2O_5图解均显示该含锰岩系具有热水沉积的特征;HREE亏损,LREE富集,且Eu负异常的特征,以及δCe值,暗示该区锰矿形成于被动大陆边缘区;V/Cr和V/(V+Ni)值指示含锰岩系形成于厌氧和缺氧环境。     

黔北黑色岩系稀土元素地球化学特征及成因意义

本文采用ICPMS方法研究了黔北下寒武统牛蹄塘组黑色岩系的稀土元素地球化学特征和形成条件。黑色岩系稀土总量在金属富集层之Mo矿层中出现峰值,向剖面上、下大致依次减小,代表了一种非正常海水沉积作用。Eu、Ce呈负异常,反映黑色岩系形成于干燥气候的陆棚边缘浅海的还原环境。稀土模式,连同La/YbCe/La、La/YbREE图解特征,说明黑色岩系为正常海水与岩浆热卤水混合沉积的产物。     

秦岭山阳水沟口组黑色岩系微量元素地球化学及其沉积成矿背景的指示意义

通过野外调研发现,秦岭造山带山阳地区水沟口组黑色岩系主要由黑灰色微晶灰岩、炭质泥板岩、灰白色粘土岩、黑灰色含炭-钙质硅板岩、灰黑色含炭泥质硅板岩及浅红色硅质板岩组成;岩系中磷结核及重晶石纹层常见。采用等离子质谱仪(ICP-MS)方法对岩系的稀土元素及微量元素测定,结果显示岩系中成矿物质含量丰富(如V、Mo、Ni、Ba、Pb、Zn、U、Ag、Cu、Cd、Tl、Bi和Cr等元素的平均含量是地壳丰度的几倍到几十倍),稀土元素和微量元素的含量与磷质、炭质以及钡关系密切;稀土模式曲线基本平行显示其成因相同;泥质和硅质岩类是主要的含矿岩性;不同程度的δEu正异常、中到弱的δCe负异常及相应的稀土、微量元素比值如Ce/La、V/(V+Ni)等指示岩石形成于干燥缺氧环境并有热水物质加入,La/Yb-Ce/La图解及La/Yb-REE图解表明岩系与海相沉积及基性岩成因关系密切。结合岩系的地质特征认为:山阳地区水沟口组黑色岩系形成于被动陆缘的一种干燥缺氧的深水-半深水滞留断陷局限海盆,期间热液(水)活动频繁、低等浮游生物发育,对岩系中矿物质的富集具有非常重要的意义。     

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.