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1.
位于班公湖 怒江缝合带与雅鲁藏布江缝合带之间的措勤盆地,在中侏罗世—早白垩世期间具有以且坎古昌 阿索裂谷带为沉积、沉降中心向南北两侧展开的古地理格局:①中晚侏罗世时期,裂谷带内由深水浊积岩、放射虫硅质岩和浅水碳酸盐岩、碎屑岩岩片及基性—超基性岩等组成;裂谷带两侧由滨浅海相碎屑岩和碳酸盐岩组成。该期盆地古地理演化具有先变深后变浅的沉积序列。②早白垩世早中期,裂谷带内仍由基性—超基性岩、深水复理石碎屑岩及放射虫硅质岩和浅水碳酸盐岩及碎屑岩组成;裂谷带两侧的日松革吉它日错分区主要由浅海相碎屑岩和灰岩组成;盆地南北部的措勤 申扎分区和木嘎岗日分区主要由滨岸 三角洲相碎屑岩及火山岩组成。各相带在纵向上均具有向上变深沉积序列。③早白垩世晚期,盆地以台地相碳酸盐岩沉积为主,裂谷带附近以发育台地边缘礁滩相沉积;裂谷带两侧的日松 革吉 它日错分区主要由开阔台地相灰岩组成;盆地南北部的措勤 申扎分区和木嘎岗日分区由局限台地相灰岩和陆源进积碎屑岩组成。 相似文献
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位于班公湖-怒江缝合带与雅鲁藏布江缝合带之间的措勤盆地,在中侏罗世-早白垩世期间具有以且坎-古昌-阿索裂谷带为沉积、沉降中心向南北两侧展开的古地理格局:①中晚侏罗世时期,裂谷带内由深水浊积岩、放射虫硅质岩和浅水碳酸盐岩、碎屑岩岩片及基性-超基性岩等组成;裂谷带两侧由滨浅海相碎屑岩和碳酸盐岩组成.该期盆地古地理演化具有先变深后变浅的沉积序列.②早白垩世早中期,裂谷带内仍由基性-超基性岩、深水复理石碎屑岩及放射虫硅质岩和浅水碳酸盐岩及碎屑岩组成;裂谷带两侧的日松-革吉-它日错分区主要由浅海相碎屑岩和灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区主要由滨岸-三角洲相碎屑岩及火山岩组成.各相带在纵向上均具有向上变深沉积序列.③早白垩世晚期,盆地以台地相碳酸盐岩沉积为主,裂谷带附近以发育台地边缘礁滩相沉积;裂谷带两侧的日松-革吉-它日错分区主要由开阔台地相灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区由局限台地相灰岩和陆源进积碎屑岩组成. 相似文献
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措勤盆地生物礁的分布有一定规律性,现今发现的8个生物礁剖面均分布于且坎-古昌-罗波-当穹错断裂两侧。结合该断裂带出现的放射虫硅质岩沉积和火山岩堆积,推测该断裂带不仅为控相断裂,而且曾经有深水沉积,由于后期的再次活动而消失于断裂带内部。断裂带两侧的生物礁应为台地边缘礁。 相似文献
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冈底斯弧弧后早白垩世裂谷作用的沉积学证据 总被引：9，自引：0，他引：9
冈底斯弧弧后地区早白垩世地层的一个显著特点是 ,由下而上普遍从陆相 -海陆交互相碎屑岩变化为海相碳酸盐岩。该地区在早白垩世中期开始了广泛的海侵 ,沉积范围由早期仅局限于班公湖 -怒江缝合带附近而扩展至羌塘地体南缘和拉萨地体 ,沉积了巨厚的台地相灰岩 ;与塔里木南部和思茅地区同期海平面变化非常不同 ,那里在晚白垩世才出现海侵。砂岩组分研究显示 ,早白垩世早期碎屑物源主要来自北侧的造山带 ,向上则逐步受到南侧火山弧的控制。在海侵层系的下部 ,发现了丰富的双峰型火山岩和双峰式火山岩碎屑。因而推断该区在早白垩世发生了强烈的裂谷沉降作用。与此同时的在印度和巴基斯坦境内的 L adakh- Kohistan弧后裂谷作用还形成了具有洋壳基底的Shyok边缘海。因此 ,在早中白垩世 ,欧亚大陆南缘为西太平洋型的活动大陆边缘 ,因强烈的弧后裂谷作用产生了一系列边缘海盆地 ;在包括青藏高原南部在内的欧亚大陆南缘 ,既没有构造动力、也没有古地理和古地形证据支持在早白垩世末 ( 99Ma± )即出现强烈的抬升。 相似文献
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塔里木盆地北部坳陷震旦纪-奥陶纪大陆裂谷性质及其演化 总被引：2，自引：0，他引：2
塔里木盆地北部坳陷是在前震旦纪结晶基底之上发育起来的大陆裂谷盆地,始于早震旦世,结束于晚奥陶世.裂谷的轴部自西向东由阿瓦提凹陷、满加尔凹陷、英吉苏凹陷(包括库鲁克塔格南区)组成,向东延伸到罗布泊以东地区.裂谷轴部与地幔隆起带和高磁异常带相对应.裂谷东部主要以半深海-深海相的浊积岩、放射虫硅质岩和笔石页岩为特征,裂谷西部和翼部则以浅水盆地相和台地相的碳酸盐为特征.裂谷早期的火山岩主要分布于中东部的切谷内,具有双峰式火山岩的特征,玄武岩属低硅高钛富碱型.据区域动力学背景、沉积特征、沉降速率,将裂谷演化划分为幼年期,成年期和衰亡期3个阶段. 相似文献
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华南新元古代裂谷盆地演化 总被引：6，自引：0，他引：6
《矿物岩石》2001,21(3):135-145
沉积学研究表明,华南新元古代沉积盆地具典型裂谷盆地沉积演化特征.代表裂谷盆地早期形成阶段的成因相组合有冲洪积相组合、陆相(或海相)火山岩及火山碎屑岩相组合、滨浅海相沉积组合、淹没碳酸盐台地及欠补偿盆地黑色页岩相组合;而代表中、后期形成阶段的成因相组合有滨岸边缘相至深海相组合,冰期冰积岩相组合、碳酸盐岩及碳硅质细碎屑岩相组合.华南裂谷盆地岩相古地理演化经历了5个重要的时期,整体上反映了一个由陆变海、由地堑-地垒相间盆地变广海盆地、由浅海变深海、盆地由小变大的演化过程.裂谷盆地的形成经历了裂谷基的形成、地幔柱作用与裂谷体的形成、被动沉降(下拗)与裂谷盖的形成三个阶段.华南裂谷盆地的形成演化与Rodinia超大陆在新元古代时期的裂解作用密切相关,它是超大陆解体过程的一个重要组成部分. 相似文献
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塔东地区寒武—奥陶纪岩相古地理分析 总被引：1，自引：0，他引：1
通过钻井资料以及露头资料的详细分析,在塔东地区寒武系—奥陶系识别出盆地相、斜坡相、台地相。根据盆地相沉积特征把塔东地区盆地相分为碳酸盐岩盆地、混积盆地、页岩-硅岩盆地三种类型。碳酸盐岩盆地相岩石类型为碳酸盐岩,混积盆地岩石类型为碳酸盐岩与页岩及硅岩互层,页岩-硅岩盆地岩石类型为泥页岩以及硅质岩。台地区发育台地边缘灰泥丘相、台缘滩相、开阔台地相等。灰泥丘主要为藻凝块岩,滩相主要为颗粒灰岩。综合塔里木盆地寒武纪—奥陶纪沉积特征提出了塔东地区碳酸盐岩沉积综合模式,并指出由台地至盆地方向,盆地由碳酸盐岩盆地向混积盆地及页岩-硅岩盆地过渡。在单井分析、露头资料分析、地震剖面分析的基础上,分析了塔东地区寒武纪—奥陶纪古地理展布。 相似文献
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中-晚二叠世,上扬子(四川盆地区)碳酸盐岩台地内发育三条北西-南东走向的裂谷,它们是重要的油气储集区带,如普光和元坝气田就产于开江-梁平裂谷两侧。但是对这些裂谷的开始时代和构造成因等关键地质问题,还缺乏详细的沉积学研究,且存在较大争议。本文通过大比例露头剖面和钻井岩芯测量以及详细的沉积相分析对比,对开江-梁平裂谷的构造沉积过程进行了深入细致的研究。调查发现,在开江-梁平裂谷北缘,中二叠统栖霞组上段至茅口组2段发育大规模斜坡相碳酸盐岩滑塌堆积,揭上扬子地块四川盆地区于中二叠世栖霞晚期开始发生伸展裂解。茅口组3段至上二叠统长兴组为超覆于滑塌堆积之上的硅质岩和碳-硅质泥岩等深水盆地相沉积,表明开江-梁平裂谷从中二叠世茅口晚期开始由伸展裂解转变为区域沉降,即开江-梁平裂谷经历了伸展裂解和区域沉降两个构造沉积阶段。伸展裂解阶段,开江-梁平裂谷是一个发育于碳酸盐岩台地内的不对称海相半地堑盆地,北侧为发育大规模碳酸盐岩滑塌堆积的下盘断斜坡带,南侧为发育缓斜坡生物碎屑滩和礁灰岩的上盘缓斜坡带;区域沉降阶段,开江-梁平裂谷表现为东翘西降的不均匀沉降,发育自东向西不断进积的潮坪-潟湖相和高能浅滩相沉积等。本文研究成结果对分析和圈定四川盆地区中-晚二叠世油气储集相带的时空分布具有重要科学意义,也为研究碳酸盐岩滑塌堆积提供了一个新范例。 相似文献
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塔里木盆地西南缘沿西昆仑山前白垩系上统依格孜牙组沉积巨厚的碳酸盐岩，分布范围西至喀什，东至叶城县克里阳地区，主要岩相有以生物碎屑灰岩为主8种岩相，碳酸盐岩主要由亮晶鲕粒灰岩和高晶生物碎屑灰岩组成；沉积环境以台地边缘、开阔台地相、局限台地相为主；沉积环境自东向西由台地边缘-开阔台地相-局限台相演变；厚度在西向东由125m减薄至10m；巨厚的碳酸盐岩沉积可以划分7个米级旋回，7个米级旋回的碳酸盐岩沉积组成了塔里木盆地西南缘白垩系新的油气勘探目的层系，丰富的牡蛎、蛤、螺等化石，稳定的台地相、礁滩相台地边缘相沉积，说明当时塔里木盆地西南缘为向西北开口的海域，古气候温暖，古盐度为半咸到咸水；海域古地理西边与塔吉克相通，东边至叶城县克里阳地区，沿昆仑山前呈显一峡长条带。 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
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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
18.
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
19.
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