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1.
雅鲁藏布江结合带南缘断层是雅鲁藏布江结合带与喜马拉雅地层区分区断层,大致呈东西向延伸。在西藏江孜县地区断层上盘为三叠系朗杰学群复理石沉积,表现为北东向褶皱和北东向逆冲断层组合;断层下盘为中生代地层褶皱冲带,以东西褶皱构造为主。断层带在江孜县白沙帕夏村以西出露宽约150m,划分出9个结构带,表现为强弱不等的韧脆性变形特征,断层面呈高角度"铲"式逆冲断层,断层倾向北西,走向北东东,断层性质为逆断层;断层微观运动方式以粘滑,断层最新的活动年龄中更新世。  相似文献   

2.
鄂尔多斯西缘褶皱—逆冲断层带的构造特征和找气前景   总被引:9,自引:1,他引:9  
野外地质观察和地震反射剖面分析表明,鄂尔多斯西缘褶皱山系和覆盖地区发育北东、北西向褶皱和西倾东冲的逆冲断层,组成褶皱—逆冲断层带。按其构造特征可归纳为以下六种类型: 1.褶皱—逆冲断层型 以桌子山褶皱—逆冲断层带为代表,构造特征为轴面西倾的不对称背向斜,逆冲断层发生在背斜陡翼上。 2.褶皱—逆冲推覆型 以小松山逆冲断层和推覆体为代表,构造特征为断面西倾东冲的逆冲断层,其上盘呈弧形突出,覆盖在下盘年轻的褶皱地层之上。 3.褶皱—犁式逆冲断层型 其典型地区是大、小罗山至马家滩地区,断面西倾东冲,上陡下缓呈犁式和坐椅式。 4.同沉积逆冲断层型 以铁克苏庙逆冲断层和其控制发育的深凹陷为代表。 5.同生基底正断层反转逆冲型 以西来蜂逆冲断层和北西向“河西系”逆冲断层为代表。 6.反向逆断层型 以断面东倾高角度呈叠瓦状错列的横山堡地区为代表。 初步认为,鄂尔多斯西缘褶皱—逆冲断层带的区域背景与A-俯冲作用有关的逆冲断层带有较大的差异,它们是在克拉通内地壳拆离作用的产物,其逆冲—推覆规模和缩短程度比A-俯冲带低, 鄂尔多斯西缘褶皱—逆冲断层的形成主要受侧向挤压力的控制。其形成方式有:(1)由于纵弯作用,先形成褶皱后产生逆冲断层。(2)受侧向挤压沿早期正断层逆转形成逆冲断层?  相似文献   

3.
准噶尔盆地南缘褶皱-逆冲断层带分析   总被引:13,自引:0,他引:13  
讨论了与准噶尔盆地南缘褶皱-逆冲断层带有关的4个问题。(1)准噶尔盆地南缘褶皱-逆冲断层带具有纵向分带、横向分段和垂向构造分层的特征:纵向上由南至北可分为逆冲推覆构造带、基底卷入褶皱-冲断带和滑脱型褶皱-冲断带三个带;横向上,基底卷入褶皱-冲断带从西至东按横向调节带分为5个段,构造特征表现为反冲断层从不发育到向南反冲的位移逐渐增大、反冲断层所滑脱的层位亦逐渐加深;滑脱型褶皱-冲断带以红车断裂为界划分为西段和东段,西段构造运动弱,构造变形具双层结构;东段构造运动较强,发育大型冲向后陆的反向逆冲断层,构造变形多具有3层结构。(2)逆冲断层-褶皱类型按其形成机制分为基底卷入型冲断-褶皱、滑脱型冲断-褶皱以及基底卷入-滑脱混合型冲断-褶皱3大类,其中,基底卷入型冲断-褶皱的特征是褶皱作用发生在逆冲断裂之前,而滑脱型冲断-褶皱以冲断和褶皱同时或冲断层先于褶皱形成为特征。(3)本区存在横向和纵向传递带。横向调节带一般分布于基底卷入型褶皱-冲断带,主要为左旋走滑断层;纵向传递带分布于滑脱型褶皱-冲断带,以逆冲断层系斜列分布和位移纵向斜列传递为特征。(4)褶皱-冲断带形成的主控因素主要有:近南北向的水平挤压作用,上新世末—早更新世末和晚侏罗世末发生的构造变形以及古近系、下白垩统和下—中侏罗统发育的三套异常高压泥岩层相关的滑脱作用。  相似文献   

4.
雪峰山西侧贵州地区中生代构造特征及其演化   总被引:4,自引:0,他引:4  
贵州中生代变形主要发生在燕山期,发育三幕褶皱变形、两幕逆冲和三幕走滑。根据区域对比、卷入褶皱的地层和褶皱间的叠加关系,判断三期褶皱的形成顺序依次为近东西向、北东向和南北向,时限在J_3—K_2之间。逆冲推覆构造主要由向北西或西逆冲的近南北向逆冲断层组成,大体与南北向褶皱同时形成;自雪峰构造带西缘向西,依次划分出根部带、中部带和前锋带。但是,在根部带识别出两幕逆冲推覆,其它两带各识别出一幕。走滑断层也有3个方向:东西向、北东向和近南北向。东西向走滑断层呈现出右行压扭的运动学特征,而大多数北东向走滑断层是左行张扭性质的。依据各个方向断层间的切割和限制关系,推测东西向走滑断层最早形成,其次是南北向逆冲断层,北东向走滑断层最晚活动。这些断裂和褶皱特征,总体表现出贵州多重多种复合联合的构造特征,最后,探讨了本区的构造成因模式。  相似文献   

5.
贵州中生代变形主要发生在燕山期,发育三幕褶皱变形、两幕逆冲和三幕走滑。根据区域对比、卷入褶皱的地层和褶皱间的叠加关系,判断三期褶皱的形成顺序依次为近东西向、北东向和南北向,时限在J3—K2之间。逆冲推覆构造主要由向北西或西逆冲的近南北向逆冲断层组成,大体与南北向褶皱同时形成; 自雪峰构造带西缘向西,依次划分出根部带、中部带和前锋带。但是,在根部带识别出两幕逆冲推覆,其它两带各识别出一幕。走滑断层也有3个方向:东西向、北东向和近南北向。东西向走滑断层呈现出右行压扭的运动学特征,而大多数北东向走滑断层是左行张扭性质的。依据各个方向断层间的切割和限制关系,推测东西向走滑断层最早形成,其次是南北向逆冲断层,北东向走滑断层最晚活动。这些断裂和褶皱特征,总体表现出贵州多重多种复合联合的构造特征,最后,探讨了本区的构造成因模式。  相似文献   

6.
贵州镇宁沙子沟地区北西向构造形迹及特征   总被引:1,自引:0,他引:1  
王筑生 《贵州地质》2000,17(1):30-33,39
沙子沟地区北西向构造是省内闻名的水城-紫云变形带向南东方向的延伸段,该北西向构造带除褶皱外,尚发育有一毓的逆冲断层构造,为一个大型的褶皱断裂构造带。它由两个褶皱带和个部断层带组成,即:打邦-六马-打万挤压褶皱带、阐益-乐纪-岜解逆冲断层带、店子上-岜闹褶皱带、白石岩-板逆冲断层带。  相似文献   

7.
依据帕米尔—西昆仑北麓新生代前陆褶皱冲断带 3条构造剖面的详细分析,发现帕米尔—西昆仑北麓除山根地带发育高角度断层外,基本上以低角度逆掩断层为主,形成与逆冲推覆构造相关的褶皱变形。乌泊尔地区表现为由山脉向塔里木盆地滑移的隐伏冲断层和上覆褶皱;苏盖特—齐姆根—甫沙地区表现为山前的三角带和向盆地扩展的两排背斜带。帕米尔—西昆仑北麓前陆褶皱冲断带的主要构造变形时间始于上新世早期(距今约 4.6Ma),断层、褶皱的变形时代由山前向盆地逐步变新,变形强度由山脉向塔里木盆地逐步减弱。帕米尔—西昆仑北麓前陆褶皱冲断带的构造缩短量为 20~70km,缩短率为 35%~50%。  相似文献   

8.
库车新生代构造性质和变形时间   总被引:126,自引:6,他引:120  
库车构造位于南天山古生代碰撞造山带之南,为塔里木盆地最北的一个构造带。它自北而南可分为边缘逆冲( 隐伏构造楔) 、斯的克背斜带、北部线性背斜带、拜城盆地、南部背斜带。每个背斜带又包含有若干逆冲断层相关褶皱,它们是断层转折褶皱、断层传播褶皱、滑脱褶皱、断层传播 滑脱混生褶皱、双重逆冲构造、突发构造、三角带构造。底部逆冲断层向南变浅,堆叠逆冲岩席向南变薄,总体上形成一个向南的逆冲构造楔。逆冲断层在斯的克背斜带侵位最早(25 Ma) ,在北部线性背斜带为169 Ma,拜城盆地中的大宛其背斜为36 Ma,南部背斜带为53 Ma( 北部) 和18 Ma( 南部) ,变形作用向南变新。库车构造是印 藏板块碰撞的内陆构造响应,是二叠纪前陆盆地复活而成的再生前陆盆地变形带  相似文献   

9.
华南地块雪峰山中生代板内造山带构造样式及其形成机制   总被引:4,自引:0,他引:4  
华南大地构造核心问题之一是江南—雪峰山造山带的属性。在前人工作基础上,对横切雪峰山造山带的地质剖面进行了详细的区域地质、构造变形和部分重点区段地震反射剖面深部构造解释,划分出5个大地构造单元:(1)湘中复合逆冲构造带。该带位处雪峰山造山带东部,以龙山复合构造穹隆等为代表,是近EW向加里东造山带与NE向燕山造山带复合叠加的结果;其中燕山期构造样式总体为倾向SE逆冲断层控制的尖棱背斜构造。(2)雪峰山厚皮逆冲构造带。该带西以大庸逆冲断裂为界,带内板溪群浅变质褶皱基底大面积出露,总体发育指向NW的断层-褶皱组合。断坪-断坡式逆冲断层从板溪群内部薄弱层发育,向浅部产状明显变陡,并导致新元古界板溪群逆冲于古生界之上,控制了沅麻等中生代盆地的形成,沿断坡形成紧闭背斜和沿断坪形成宽缓向斜;表明其为典型的断层相关褶皱。断层褶皱组合与地表剥蚀共同作用,形成飞来峰和构造窗。(3)以梵净山构造穹隆为代表的梵净山—走马构造穹隆带。该带呈NE向长垣状,核部出露新元古界下部梵净山群。断坪-断坡式逆冲断层深切梵净山群,在断层上盘形成不对称箱状背斜。因此总体为典型的厚皮逆冲作用下的断层相关褶皱。(4)隔槽式逆冲构造带。此带主要发育一系列轴向NE的箱状背斜和尖棱向斜。箱状背斜核部为寒武系,向深部卷入震旦系—板溪群,形成基底卷入的断层-褶皱组合,其浅部形成叠瓦状逆冲断层-褶皱组合,从而构成主动双重逆冲构造。(5)华蓥山断裂与齐岳山断裂间的隔档式薄皮构造带。带内以发育尖棱背斜和箱状向斜为特征,是倾向SE断坪-断坡控制下的断展褶皱组合。上述5个构造单元变形区域卷入了上三叠统—下侏罗统,但为上白垩统角度不整合覆盖,表明变形时间为中生代中晚期,并且有从SE向NW渐次变新的趋势。将各构造单元及不同构造层次构造组合联系起来,建立起以断层相关褶皱为基本构造样式,从SE向NW,从深部向浅部发展的雪峰山中生代板内造山带的递进演化运动学新模式。  相似文献   

10.
大青山逆冲推覆构造发育在石拐断陷盆地南侧,由一系列规模大小不等向南倾的叠瓦状逆冲推覆断层构成,由南南西向北北东方向推覆,是单冲型逆冲推覆构造。由北向南分为前缘挤压滑脱构造带、斜歪倒转褶皱—逆冲断层带和逆冲推覆岩席及叠瓦状逆冲断层带。  相似文献   

11.
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.
13.
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.
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.
从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返   总被引:4,自引:1,他引:4       下载免费PDF全文
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   

16.
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  
陈银生 《世界地质》1999,18(1):54-59
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   

18.
19.
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.  相似文献   

20.
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   

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