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1.
秦岭商—丹断裂带南缘构造岩片地层初析 总被引：2，自引：0，他引：2
商－丹断裂带南缘是由一系列不同时代、不同类型的构造－地层岩片叠积而成的。这些构造地层岩片出露虽不完整，但多数显示有序，其时代、层序均可以鉴别。它们分别代表了不同构造发表阶段和多种类型盆地沉积。 相似文献
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吉林色洛河群的重新认识 总被引：8，自引：2，他引：6
色洛河群出露于吉林省色洛河-华集岭一带,位于华北克拉通北缘东段,长期以来一直被认为是中新元古代地层。最近的野外调查和定年研究表明,它包含了时代、成因、构造样式、变质程度不同的变质地层和变形的花岗岩,作为一个岩石地层单位已不合适,应予解体。原划分的色洛河群至少由4部分组成：新太古代变质火山-沉积地层（锆石SHRIMP年龄为2 517~2 534 Ma）、晚古生代变质火山-沉积地层（英安岩锆石 SHRIMP年龄为 252 Ma）、二叠纪片麻状杂岩体（锆石SHRIMP年龄为260 Ma）和侏罗纪糜棱岩化花岗岩（锆石SHRIMP年龄为168 Ma）。前人在色洛河一带定义的色洛河岩群为一套变质火山-沉积岩系,可能是形成于晚古生代的一套地层,也可能是由不同时代的构造岩片构成的构造杂岩。 相似文献
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甘孜-理塘结合带内各种构造岩片(块)均遭受不同程度的变质变形,属于整体无序、局部有序的非史密斯地层,通过查明各类岩片(块)的岩石组合、来源、时代、变形变质及裂解、运移、拼合、定位历程,重新定义了“理塘蛇绿岩群”的含义,并新命名为“理塘蛇绿混杂岩群”。按结合带内岩块的不同组分、不同来源、不同时代、不同变形变质程度的不同,对各类岩块进行四维裂解拼合复原后划分为两个岩组(卡尔蛇绿岩组、瓦能蛇绿岩组)及碎屑岩、大理岩等组成的5类外来岩块。这对于进一步研究甘孜-理塘结合带的造山机制及构造演化历程有着十分重要的意义。 相似文献
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对海南岛大地构造特征的新探索 总被引：1，自引：0，他引：1
当前对海南岛大地构造的认识主要有槽台说、地洼说、岛弧说和板块构造说,所有这些观点,包括活动论的板块构造都是建立在以垂直升降运动为主的固定论的基础上的,都认为地层和岩石,特别是花岗岩都是原地形成的,并依此建立了多阶段、多旋回的地质-构造旋回或地槽、地台、地台活化(或地洼)的发展阶段和演化历史,集中体现了活动与稳定相互转化的递进过程。当我们重新分析研究已有资料并采用新全球动力学理论和抽拉构造形成褶皱带、造山带模式的理论来重新认识海南岛的大地构造时,以上观点都值得商榷。研究发现:(1)海南岛前白垩系的所有地层都存在顶底不清、接触关系不明并常呈断层接触,岩石地层的建立不符合相关规范,不能按时代先后顺序建立全岛统一的地层柱,也不能按时代顺序和不整合上下关系建立地质-构造旋回和大地构造发展阶段;(2)组成全岛最广的岩石是片麻状花岗岩,与沉积-变质岩占多数的大陆褶皱带(造山带)明显不同,具片麻状、混合岩化的花岗岩实属太古宙的TTG岩套,它不是侵位于相邻的前白垩系地层中的侵入岩,而是以抽拉-逆冲-推覆出地表的岩片构造;(3)全岛岩石地层按接触关系自下而上可划分出5个岩片构造系统:原地系统、准原地系统和3个外来系统,并以此为依据划分出海南岛的构造单元;(4)海南岛所属的一级构造单元是青藏高原涡旋-甩出-热核反应构造体系,二级构造单元为南海-海南岛旋扭涡旋构造区,三级构造单元为海南岛旋卷-扭动构造及其内部的砥柱构造;(5)砥柱状隆升与南海基性火山岩中的热点相复合,是海南岛异常突出海面的根本原因,属原地系统;(6)不同岩片构造系统按抽拉构造的方式叠置堆垛在砥柱状-热点构造之上是海南岛大地构造的基本特征;(7)海南岛的大地构造发展史只能从中生代晚期开始。 相似文献
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吉林省前寒武纪地层 总被引：3，自引：1，他引：3
吉林省前寒武纪地层可见有太古宙变质表壳岩系、古元古代中深变质火山-沉积岩系、吉南新元古代陆源碎屑岩-碳酸盐岩组成的盖层沉积岩系和吉北造山带新元古代变质火山-沉积岩系4种类型.其中太古宙地层龙岗陆块具有多陆块拼贴的特点,可划分为龙岗岩群(四道砬子河岩组、杨家店岩组)、夹皮沟岩群(三道沟岩组、老牛沟岩组)、板石沟岩群、南岗岩群(鸡南岩组、官地岩组)、清原岩群.分别代表白山镇地块、夹皮沟镇地块、板石沟地块、和龙地块和清原地块的变质表壳岩系,其中除龙岗岩群可能为中太古代外,其余地质体的时代均为新太古代.古元古代地层有集安岩群、光华岩群和老岭岩群,前两者为古元古代早期裂谷环境沉积,分别可进一步划分为蚂蚁河岩组、荒岔沟岩组、大东岔岩组、双庙岩组和同心岩组,沉积时限为2 300～2 100Ma;后者为古元古代晚期内克拉通凹陷沉积,可进一步划分为林家沟岩组/达台山岩组、珍珠门岩组、花山岩组、临江岩组和大栗子岩组,沉积时限为1 900～1 800Ma.吉南新元古代地层的岩石地层学属性基本清楚,按新元古代三分的观点,其中细河群及其以下地层时代为青白口纪.浑江群时代为震旦纪,吉南地区缺失南华系.吉林省北部造山带中沿色洛河-海沟-青龙村-江域一线的元古宙地层事实上为不同时代、不同性质的构造岩片堆叠体,属于构造地层学范畴;具有层状地层特征的仅有敦化地区的塔东岩群、蛟河地区的新兴岩组、九台地区的机房沟岩群、辽源地区的西保安岩组以及安图地区的万宝岩组,时代可暂置于新元古代. 相似文献
7.
羊拉铜矿床的构造混杂岩由几个不同时代、不同岩性组合的构造岩片组成,主要矿体局限在二叠系构造岩片中,二叠纪的构造混杂形成矿区的叠瓦式构造。燕山晚期-喜马拉雅期的构造活动表现为矿区内的左行走滑断层、斑岩侵入,并伴生铜钼矿化。 相似文献
8.
雅鲁藏布江缝合带内构造岩片划分及形成——以仲巴-桑桑段为例 总被引：1，自引：2，他引：1
构造岩片作为造山带中非史密斯地层地区的填图单位有其重要的地质意义,本文将雅鲁藏布江缝合带分为6大构造岩片,其中蛇绿混杂岩岩片又分4个次级岩片,进一步阐述了缝合带内不同单元具有不同岩性和不同构造型式,是一条复杂的构造带,并发现俯冲板块一侧的不同构造单元具有自南而北,由脆性变形到低温高压变质、脆-韧性变形,超基性岩的深层次韧性变形的分布规律,大多数岩片的分布是通过多重逆冲推覆型或走滑型的断层将其从地壳深部挤出定位的。雅鲁藏布江缝合带内的构造岩片特征,反映了冈瓦那大陆北缘自三叠纪末期到第四纪经历了裂陷、扩张、多岛洋、闭合、俯冲、碰撞、褶皱、推覆造山的全过程。 相似文献
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依据大兴安岭呼中地区中浅变质岩系构造变形特征，对其划分了5个构造岩片，其经历了两期构造变形作用的改造，早期伸展构造改变了原始地层的基本结构，晚期收缩体制下强烈的推覆挤压又造成了构造岩片的移位和叠置，从而使地层广泛非史密斯化，根据不同岩石组合变形特征，划分了8个构造地层类型，在此基础上，结合建造组合特征，建立了构造地层单位—吉祥沟岩组和大网子岩组，两岩组并称为倭勒根岩群。 相似文献
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在１∶５万羊曲幅区域地质调查中,通过采取非史密斯地层理论及构造岩片为核心的多重划分方法,确定羊曲地区分布的元古宙地层的形成时代为古元古代,变质程度属低角闪岩相,为红柱石一矽线石型低中压变质相系。经区域地层对比,该套地层为扬子地块裂解块体的一部分,其与二叠纪火山弧岩片及弧前复理石岩片共同构成昆秦接合部构造混杂带的北东端。 相似文献
11.
Guboglo M. N. 《GeoJournal》1980,4(1):53-58
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. 相似文献
12.
Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
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″. 相似文献
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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. 相似文献
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摩擦桩基桩土间极限摩阻力取值问题探讨 总被引：1，自引：0，他引：1
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。 相似文献
17.
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。 相似文献
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某高速公路下伏煤矿采空区稳定性分析 总被引：10，自引：0，他引：10
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。 相似文献
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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. 相似文献
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Michel Westphal Mikhail L. Bazhenov Jean Paul Lauer Diamar M. Pechersky Jean-Claude Sibuet 《Tectonophysics》1986,123(1-4)
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. 相似文献