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1.
新疆北部西准噶尔造山带的构造属性长期以来存在争议,确定该地区中、新生代的构造事件及隆升过程是研究该地区陆内变形的关键所在。本文对造山带内山间盆地——和什托洛盖盆地的构造抬升事件进行系统分析,基于研究区野外地质调查及断裂解析,识别出C/J、J/AnJ、J/E和K/E以及E/N等5期区域不整合面,这些不整合是构造活动的直接证据。盆地中、新生代受南北两条控盆断裂近N-S向挤压应力持续挤压。砂岩样品磷灰石裂变径迹年龄分布在晚侏罗世末期—早白垩世早期（149～125 Ma）、早白垩世中期（121～109 Ma）和晚白垩世早期（80.0～77.7 Ma）3个区间,反映出该地区在这3个时期发生了明显的冷却抬升事件,3期冷却抬升事件与野外地质特征有很好的地质响应。热史模拟表明晚侏罗世—早白垩世（160～110 Ma）、晚白垩世（85～65 Ma）和渐新世—上新世（30～5 Ma）发生了快速隆升事件。盆地构造抬升的主要应力为周缘山系抬升及断裂活动挤压。综合研究表明,盆地中、新生代经历了3期明显的构造抬升事件,与中、新生代印支运动、燕山运动和喜山运动远程效应有很好的耦合性。 相似文献
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桐柏——大别山主要构造热事件及40Ar/39Ar地质定年研究 总被引：23，自引：0，他引：23
桐柏——大别山是一条复合造山带。在其演化过程中曾经历了扬子旋回（1000Ma-761Ma）和加里东旋回（470Ma-401Ma）两个板块构造旋回的俯冲-碰撞造山作用，之后又经历了早、中华力西（357Ma-314Ma）的平移走滑和晚华力西（286Ma-261Ma）、印支期（224Ma-185Ma）、燕山期（130Ma-111Ma）逆掩或逆冲推覆的陆-陆叠覆造山作用。印支期的高压超高压变质岩系是在陆-陆叠覆造山作用下形成的。燕山期的造山不仅具显著的深层次构造岩浆作用特点，而且还伴随快速的隆升作用。 相似文献
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笔者对中天山微陆块北缘托克逊干沟地区角闪岩相变质岩中的锆石进行了U-Pb年代学研究,结果证明变质沉积岩中的碎屑锆石记录了从太古宙至元古宙(3320～530 Ma)的源区岩浆热事件,变质火成岩中的岩浆锆石记录了新元古代晚期(550 Ma)的岩浆作用,而变质锆石记录了晚泥盆纪(385～360 Ma)的变质作用。这一定年结果表明,中天山微陆块北缘的造山作用很可能发生在华力西期,中天山微陆块形成于新元古代以前,但并没有经历前寒武纪变质作用,具有与塔里木克拉通明显不同的前寒武纪构造演化历史。因此,中天山微陆块很可能是一个独立的块体,并不支持其是从塔里木板块分离出来的观点。 相似文献
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《大地构造与成矿学》2020,(4)
砂岩型铀矿床具有水成的、动态的、开放的特征,其形成及后期改造与盆地构造隆升关系密切。本文在热年代学研究的基础上,查明了伊盟隆起中生代以来具有四期构造抬升事件:150～126 Ma、110～100 Ma、100～75 Ma、50～35 Ma,且四期抬升事件隆升强度逐渐降低。其中第一期(150～126Ma)抬升事件以南北向的差异性抬升过程为特征,第二期(110～100 Ma)抬升事件表现为东隆西降的掀斜过程,第三、四期(100～75 Ma和50～35 Ma)抬升事件表现为整体抬升。通过与伊盟隆起周缘地区对比,发现伊盟隆起与贺兰山地区作为统一的整体共同经历了四期抬升事件,30Ma以来贺兰山快速隆升与鄂尔多斯盆地分离,并伴随银川盆地形成。在系统统计研究区内砂岩型铀矿成矿年代学成果基础上,总结出伊盟隆起内三期砂岩型铀矿床成矿过程:第一期为早白垩世128.2±4.2Ma～120±11Ma;第二期为晚白垩世90±5.3Ma～71±8 Ma;第三期为古近纪古新世-新近纪中新世54.6±1.8 Ma～20±2Ma。第一期成矿作用发生于第一期和第二期构造抬升转换期,第二期和第三期成矿作用分别与第三期和第四期抬升作用密切相关,构造隆升强度较大并不利于砂岩型铀矿床的沉淀和矿体就位。30 Ma以来发育于伊盟隆起的砂岩型铀矿床进入成矿后演化阶段。 相似文献
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珲春地区早印支期I—A型花岗岩系的特征及其大地构造意义 总被引：4，自引：2，他引：4
珲春市地域内花岗岩出露面积约达3000km^2，占地域总面积一半以上，前人均认为以大荒沟花岗闪长岩大岩基为代表折花岗岩类主要为华力西晚期的产物，并成为晚华力西期地槽（褶皱带）存在的重要理论依据之一，八十年代以来，新的地质调查逐步对大荒沟大岩体进行了岩石谱系单位划分，确认存在着闪长岩-花岗闪长岩-二长花岗岩-钾长花岗岩-晶洞（文象）钾长花岗岩呈套叠式产出的岩石序列，时代为早印支期，成因类型为I-A型花岗岩系，形成于早印支造山运动的过程之中，反映了整个陆缘造山旋回的成岩浆作用的特点，标志兴凯地块西部陆缘活动带过渡型陆壳经历了早印支期的构造岩浆作用。转化为成熟陆壳的过程。 相似文献
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湖南雪峰山地区白马山花岗岩年代学特征及构造意义 总被引：2，自引：0，他引：2
采用SHRIMP锆石高精度测年方法和磷灰石裂变径迹方法,开展雪峰山地区白马山岩体年代学研究,认为岩体所在雪峰山中段地区加里东期无岩浆活动,白马山岩体主要形成于印支晚期至早燕山期(测点数据区间主要集中在(176±4.4)～(219.3±5.2) Ma),中晚燕山期有微弱活动(测点数据在(172.9±3.6)～(109.3±2.5) Ma间偶有分布),系陆内碰撞地壳加厚局部熔融结果。晚燕山期以来岩体有明显的岩浆期后热液活动(磷灰石裂变径迹年龄集中在(53.8±5.4)～(91.5±4.6) Ma),隆升幅度较小;进而,在综合雪峰山地区基本地质特征及区域构造背景研究的基础上,认为该区基本地质特征及白马山岩体年代学数据与区域构造背景有着明显的吻合,受晚三叠世-早侏罗世特提斯构造域向太平洋构造域转变的构造环境控制。印支期以来雪峰山地区共经历晚印支期、早燕山期、中燕山期、晚燕山期、早喜山期5期构造事件。其中,晚印支期与古特提斯洋关闭印支板块与华南碰撞陆内造山有关;早燕山期以来,受控于古太平洋俯冲影响,雪峰山地区表现出时空的差异性,或挤压逆冲,或呈构造伸展。 相似文献
8.
中国东部中亚构造带及向环太平洋构造带的转化 总被引：4，自引：0，他引：4
王东方 《华北地质矿产杂志》1995,10(2):135-142
中亚古亚洲洋的消失可由该地区大量晚元古后期－泥盆纪残余洋壳和高压变质带的存在来说明，其中大量８００～５５０Ｍａ蛇绿岩和高压变质带说明兴凯运动是主要造山期。加里东和华力西造山运动是其后续运动，早石炭世是一个转折期，早石炭世地层基本缺失，洋壳残片不再出现，变质作用突然减弱，表明中亚地区构造机制已逐渐转入大陆内部。石炭二叠纪地壳开始拉伸，形成了晚古生代裂谷并产生强烈岩浆作用。二叠纪末。早中生代全区隆起，残余海盆地消失，西伯利亚地台以其盾形前缘向南推移，形成推土机机制改变了加里东－华力西期的东西向构造格局，形成折接的类弧形构造，其东部为北东向构造，前缘为东西向，西部为北西向，总体形成宏伟的推覆断层及走滑断层系，早中生代中国东部环太平洋构造带以南北向为特征，由东而西的侧压力转换成剪切分量，加强了北东向的走滑和拖曳。在这一过程中，环太平洋构造以最接近的应力场和最低的地动能消耗、制动，继承和改造了晚末期中亚构造系，达到两个大地构造区系的交替和过渡。 相似文献
9.
抱板杂岩(抱板群)是海南岛目前已发现的最古老前寒武纪结晶基底,记录了多期构造热事件,是研究海南岛大地构造属性的重要窗口。本文通过对海南岛冲卒岭地区抱板杂岩变质沉积岩、变质基性岩和伟晶岩脉的锆石和独居石LA-ICP-MS U-Pb年代学研究,来确定抱板杂岩所经历的多期构造热事件及其所代表的构造意义。研究结果显示,抱板杂岩主要由中元古代变质沉积岩、花岗质片麻岩和变质基性岩组成,经历了中元古代晚期-新元古代早期(1.3～0.9Ga)、早古生代(470～440Ma)、三叠纪(～230Ma)等多期构造热事件的改造。中元古代晚期-新元古代早期构造热事件与罗迪尼亚超大陆的汇聚有关;早古生代构造热事件与东冈瓦纳古陆北缘的增生造山作用有关;三叠纪构造热事件是印支陆块与华南陆块碰撞拼合的远程响应。综合上述研究成果和区域对比分析,认为海南岛与印支陆块具有相似的前寒武纪结晶基底和多期构造热事件的记录,表明二者具有明显的亲缘关系。 相似文献
10.
中俄朝毗邻地区古吉黑造山带岩石及年代记录 总被引：18，自引：1，他引：17
新近查明的岩石及年代记录揭示,中俄朝邻域古吉黑造山带的基底是由约1000Ma的构造、岩浆、变质、成矿等耦合事件拼接的Rodinia超大陆的部分所组成.阿森特-兴凯期造山作用代表了本区对Rodinia的裂解（约始于900Ma）至冈瓦纳-劳伦超大陆拼合（545~525Ma）的积极响应,并属古亚洲洋的重要发展阶段.加里东构造旋回（440~425Ma）,早华力西构造旋回（350Ma）,晚华力西-早印支构造旋回（250~230Ma）,完成了古亚洲洋向古特提斯洋（海）的转换,实现了古欧亚大陆的形成,是对Pangea古陆聚合的积极响应.特别是早印支旋回,形成了"陆陆拼贴-陆内俯冲-造山带崩塌"连续过程的完整的岩石及年代记录. 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
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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
14.
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
15.
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
17.
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
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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
20.
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