全球沉积盆地结构与构造演化特征:洲际纬向超长剖面对比研究

沉积盆地地层及其结构记录了盆地的构造演化过程,并由其所处的不同历史时期的构造背景所决定。全球油气勘探的不断深入和大量地震剖面的完成为系统认识盆地构造演化提供了大量基础资料。本文在板块构造理论的指导下,收集了全球上百个重要沉积盆地的资料编制了2条洲际纬向超长剖面:(1)北美-北非-中东-中亚-东亚纬向超长剖面;(2)南美-非洲纬向超长剖面。这两条洲际纬向超长剖面能直观地显示出不同类型盆地构造演化阶段及其时空对应关系受控于板块运动。盆地发育的程度(沉降厚度、沉降率、构造间断)及其完整性(规模大小、剖面形态、垂向结构),受控于其所处区域的构造背景。北美和南美大陆不同类型沉积盆地存在有序并列的特征:自西向东均为大洋盆地、海沟、弧前盆地、弧后前陆盆地、克拉通盆地、裂谷盆地和被动陆缘盆地。由于板块边界作用影响,相同板块上不同的盆地群之间具有密切的构造-沉积联系和构造事件响应,北非和非洲中部东西向剖面依次发育被动陆缘(西部)-克拉通(中部)-裂谷(偏东部)的特征。     

中国及邻区沉积盆地群结构与构造演化探讨——来自长剖面的研究对比

由多陆块汇聚而成的亚洲大陆发育类型多样的沉积盆地,是认识盆地构造演化的理想地区。本文通过绘制4条穿过亚洲大陆不同盆地群的超长剖面图,探讨不同盆地的结构类型及沉积盆地群与板块边界、深部构造背景之间的关系。与其他大陆相比,亚洲大陆沉积盆地规模普遍小,原型盆地保存较差。在盆地基底组成上,时代差异较大。古老克拉通陆块基底上的盆地保存较好,而造山带、洋壳基底上的盆地沉降幅度较大,并且易被叠加改造。不同类型盆地的构造演化受控于板块构造边界作用。由于亚洲大陆板块边界运动性质多变和陆块规模较小,造成其盆地群构造上强烈不稳定。中亚、特提斯、西太平洋三大构造域,西伯利亚、印度、华北、塔里木、扬子、印支等克拉通陆块群,及地幔柱活动(如西西伯利亚玄武岩省)的时空叠加,控制了亚洲盆地群显生宙以来的构造演化,并造成其盆地类型和后期保存的明显差异。     

欧亚大陆中部盆地群大剖面的编制及其构造意义

盆地结构记录了盆地演化特征,盆地群结构和构造特征由其所处的构造背景和板块边界决定。随着油气勘探的不断深入,积累了大量地震剖面,为盆地群剖面特征对比,提供了大量的基础资料。本文从大地构造背景着手,通过筛选地震与地质剖面,大致沿北纬39°绘制了欧亚大陆东西向剖面(在东部北黄海盆地有向南的偏转):西起黑海盆地,东至琉球海沟,剖面长约12000km,横穿18个盆地,涵盖克拉通盆地(塔里木原型盆地等)、裂谷盆地(太原盆地、渤海湾盆地等)、前陆盆地(黑海盆地、南里海盆地等)和弧后盆地(东海盆地)等多种盆地类型。其中,陆壳上的盆地发育在前寒武基底上,演化历史悠久;褶皱基底、洋壳基底和洋陆过渡壳基底上发育的盆地主要发育在中新生代。通过详细对比剖面各段结构和构造演化特征,发现中新生代构造活动决定了欧亚大陆中部盆地群最终格架,盆地多具有多期叠合改造的特征。剖面西段盆地群普遍具有中生代伸展断陷,叠加后期挤压坳陷的特征;剖面东段盆地群具有中生代断陷,叠加后期坳陷的特征。现今构造格架由西到东表现为前陆坳陷到弧后坳陷,鄂尔多斯盆地和沁水盆地是本剖面线结构特征分段的枢纽。     

西太平洋中段沉积盆地新生代构造-沉积演化特征

西太平洋中段位于欧亚板块、太平洋板块和印度洋板块的交汇处,是全球沟弧盆体系最为发育的地区,主要发育弧后盆地、弧前盆地和陆架边缘盆地。文中通过综合研究西太平洋中段17个盆地的大地构造背景、盆地的形成与演化和沉积特征后认为:(1)各类盆地的构造-沉积演化均经历4个期次。弧前盆地和弧后盆地的构造-沉积演化可分为俯冲期(K2-E)、盆地发育期(N11-N13)、沉降期(N14-N15)和挤压期(N2-Q):俯冲期发育火山岩和变质岩基底,局部为海相碎屑岩;盆地发育期以海相沉积为主,伴有火山活动,局部发育陆相沉积;沉降期以海相和三角洲相沉积为主;挤压期以三角洲相和海相沉积为主,局部发育河湖相沉积。陆架边缘盆地的构造-沉积演化也分为4期,分别为前裂陷期(K2-E1)、裂陷期(E2-E31)、拗陷期(E32-N13)和沉降期(N14-Q):前裂陷期和裂陷期主要发育冲积扇—河流—湖泊沉积体系,火山活动强烈;拗陷期沉积环境由陆相向海陆过渡相演化;沉降期以海相和海陆过渡相沉积为主。(2)不同类型盆地的构造-沉积演化特征各不相同:弧前盆地构造以挤压和板块俯冲为主,平均沉积厚度为3.6 km,总体由海陆过渡相向陆相演化;弧后盆地构造受板块俯冲后撤和弧后洋壳扩张作用控制,平均沉积厚度为4.8 km,总体由海相向海陆过渡相演化;陆架边缘盆地构造呈下断上拗双层结构,平均沉积厚度超过10 km,总体由陆相演化为海相。     

南黄海海域中生代前陆盆地形成的构造背景

南黄海盆地占据了下扬子板块的主体,自元古宙以来经历了多期构造运动,受到华北板块、扬子板块、华南板块、太平洋板块多个板块相互作用的影响,形成多期盆地演化阶段的叠合盆地。分析了南黄海盆地前人钻井资料及最新二维地震资料,并与下扬子苏北盆地地层及构造特征进行对比,认为整个下扬子区域受华北—扬子板块碰撞的影响,经历了中生代前陆盆地演化阶段。下扬子陆域部分地区发育相对完整的中生代沉积,记录了华北—扬子板块之间洋壳消减、陆陆碰撞、前陆盆地发育及碰撞后活动。而在下扬子对应海域延伸部分的南黄海盆地中,仅在盆地北部烟台坳陷东北缘通过钻井证实有侏罗纪前陆盆地地层,钻遇地层仅发育侏罗系上部陆相沉积,在地震剖面中可以解释出侏罗系下部海陆交互相地层,向上转变为陆相沉积地层。对比下扬子陆域与海域地层发育情况,华北—扬子板块碰撞造山过程对于下扬子整个区域的影响因地而异,在三叠纪末期—侏罗纪时期南黄海盆地内沉积缺失,南黄海海域区处于广泛抬升状态,印支运动期间地层挤压活动强烈,烟台坳陷内海相地层中逆冲断层广泛发育。在南黄海盆地东北缘,前陆盆地侏罗系地层发育于南倾边界断层的上盘,认为南黄海盆地侏罗纪前陆盆发育的构造背景受到同期北侧千里岩超高压变质带从深部折返影响,随着千里岩隆起带的快速抬升,为南黄海盆地北缘提供了沉积空间及物源,沉积了大套的侏罗系前陆盆地地层。     

西太平洋中段沉积盆地新生代构造-沉积演化特征*

西太平洋中段位于欧亚板块、太平洋板块和印度洋板块的交汇处,是全球沟弧盆体系最为发育的地区,主要发育弧后盆地、弧前盆地和陆架边缘盆地。文中通过综合研究西太平洋中段17个盆地的大地构造背景、盆地的形成与演化和沉积特征后认为:(1)各类盆地的构造-沉积演化均经历4个期次。弧前盆地和弧后盆地的构造-沉积演化可分为俯冲期(K₂-E)、盆地发育期((Ｎ_１^１ -Ｎ_１³)、沉降期(Ｎ_１⁴-Ｎ_１⁵)和挤压期(N₂-Q):俯冲期发育火山岩和变质岩基底,局部为海相碎屑岩;盆地发育期以海相沉积为主,伴有火山活动,局部发育陆相沉积;沉降期以海相和三角洲相沉积为主;挤压期以三角洲相和海相沉积为主,局部发育河湖相沉积。陆架边缘盆地的构造-沉积演化也分为4期,分别为前裂陷期(K₂-E₁)、裂陷期(E₂-(E₃^１)、拗陷期(E₃²-Ｎ_１³)和沉降期(Ｎ_１⁴-Q):前裂陷期和裂陷期主要发育冲积扇—河流—湖泊沉积体系,火山活动强烈;拗陷期沉积环境由陆相向海陆过渡相演化;沉降期以海相和海陆过渡相沉积为主。(2)不同类型盆地的构造-沉积演化特征各不相同:弧前盆地构造以挤压和板块俯冲为主,平均沉积厚度为3.6,km,总体由海陆过渡相向陆相演化;弧后盆地构造受板块俯冲后撤和弧后洋壳扩张作用控制,平均沉积厚度为4.8,km,总体由海相向海陆过渡相演化;陆架边缘盆地构造呈下断上拗双层结构,平均沉积厚度超过10,km,总体由陆相演化为海相。     

晚三叠世—中侏罗世中国南方前陆盆地构造格局的形成与演化

晚三叠世—中侏罗世在中国南方的构造历史上是一个十分重要的转折时期,原来较为稳定的华南板块裂解为扬子板块和东南板块,并由原先的台地沉积转变为前陆盆地沉积。在扬子板块南、北两缘逐渐形成了南前陆盆地带和北前陆盆地带,同时在扬子板块东南侧还存在一裂陷盆地带。根据该区的沉积、构造等特征,又可划分出三个阶段:晚三叠世早—中期,晚三叠世晚期—早侏罗世,中侏罗世。其中晚三叠世晚期—早侏罗世为前陆盆地发育的鼎盛时期,此时的北前陆盆地带自西向东主要由上扬子、中扬子、下扬子三个周缘前陆盆地及合肥冲断前渊盆地构成;南前陆盆地带主要由兰坪—思茅、楚雄、南盘江、桂东南等四个弧后前陆盆地及湘西、湘赣等冲断前渊盆地(群)构成。北前陆盆地带属周缘前陆盆地性质,而南前陆盆地带主要为弧后前陆盆地性质。同一前陆盆地带在上述三个不同阶段有不同的沉积—构造特征,而且在同一前陆盆地带内的不同盆地,其形成与演化的时间也有差异。前陆盆地的演化均与相邻造山带演化相关,造山带隆起的强度愈大,持续时间愈长,则相邻前陆盆地的沉积厚度亦愈大。     

龙门山中段中生代前陆盆地的构造演化史

依据龙门山中段中生代盆地的基底性质，沉积构造组合和构造变形，论证了川西拗陷是组合和构造变形，论证了川西拗陷是在印支期发育于扬子板块活动大陆边缘的弧背（前陆）盆地，前陆盆地的构造变形是经印支期构造变动和喜马拉雅期叠加改造形成的推覆构造，并讨论了龙门山中段中生代前陆盆地的构造演化历史。     

德格—中甸微板块在三叠纪时期各沉积构造带的性质和沉积盆地演化

德格—中甸微板块是在晚二叠世初随甘孜—理塘洋的产生而从扬子板块西缘分离出来的。在三叠纪时期受金沙江缝合带与甘孜—理塘缝合带构造作用的相互影响,其沉积构造性质也由被动边缘盆地演化为活动边缘盆地,同时分裂为白玉—义敦前陆盆地,昌台—乡城岛弧带、玉隆—稻城弧前盆地。     

新疆北部晚古生代沉积盆地类型及其沉积特征

新疆北部晚古生代，构造岩浆活动十分强烈并发育复杂且变迁迅速的众多沉积盆地。沉积盆地可划分为７类（大陆边缘裂谷类、岩浆弧类、弧前盆地类、边缘海盆地类、弧后前陆盆地类、边缘前陆盆地类、海沟－洋盆类）１９型。沉积组合复杂多变，不同类型的沉积盆地各具特色。沉积盆地的演化经历了５次重大变革。新疆北部晚古生代沉积盆地随新疆北部板块的拉张－俯冲－碰撞而产生、发展、消亡。     

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。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

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.     

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.