青藏高原南缘现今地球动力学研究

喜马拉雅构造带于新生代时期经历了两代受力条件截然不同的形变。早期造山挤压形变与造山后的引张形变、青藏高原和高喜马拉雅的大幅度抬升。大致低喜马拉雅范围即青藏高原南缘，现今构造活动与青藏高原和高喜马拉雅块断抬升相辅相成。流行的板块聚合动力学模式，即使早新生代发生过，晚新生代以来已经灯熄。东亚大陆现代形变与地震活动的驱动力不可能源于青藏高原南缘被动挤压，而是取决于与高原隆起相关的深部主动动力学过程     

青藏高原西北缘地球动力学初探

从新构造单元划分、活动断层、活动褶皱、地壳升降运动、地震活动及新生代火山活动等方面论述了该地区的新构造及现代构造运动特征，最后讨论了该区和青藏高原形成的地球动力学问题。认为青藏高原在其形成过程中既有印度板块的向北俯冲和碰撞作用，又有塔里木块体的向南楔入，既有高原物质向外扩展作用，又有周边拗陷向高原内部渗透作用，所以青藏高原的岩石圈是处于一个四面受压，上出下入的动力学状态     

青藏高原中东部地壳运动的GPS测量分析

根据1993年和1995年对青藏高原地壳运动进行的两期 GPS 监测的实测结果,分析了青藏高原现今地壳水平运动情况,并将其与不同地质运动模型结果进行了比较。结果表明,青藏高原现今地壳水平运动速率和方向与地质结果符合很好。目前,青藏高原大约以38.6mm/a 的速度向北东方向运动。     

Analysis on monitoring crust movement by using GPS in Qinghai-Xiqang Plateau

Based on the analysis of the 1993 and 1995 GPS data acquired from crust movement and deformation monitoring in thc Qinghai-Xizang Plateau, the following preliminary conclusions could be drawn: the levelly moving rate and direction of the land massifs in the Qinghai-Xizang Plateau tally with the viewpoint generally held by geologists and geophysicists irr recent years; the accuracy of monitoring crust movement has reached the world advanced level; the result has provided valuable and reliable information to the quantitative analysis of the modern crust movement and deformation in the plateau. Project supported by the Nntional Natural Science Foundation of China.     

Analysis of the rising and sinking movement of the crust in Qinghai－Xizang Plateau，China

ＡｎａｌｙｓｉｓｏｆｔｈｅｒｉｓｉｎｇａｎｄｓｉｎｋｉｎｇｍｏｖｅｍｅｎｔｏｆｔｈｅｃｒｕｓｔｉｎＱｉｎｇｈａｉ－ＸｉｚａｎｇＰｌａｔｅａｕ，ＣｈｉｎａＺｉ－ＬｉｎｇＬＵ（吕梓龄），ＺｈｅｎｇＺＨＵＡＮＧ（庄真），Ｚｈｕ－ＷｕＦＵ（傅竹武），Ｊｉａ－...     

中国西部三维速度结构及其各向异性

本文用覆盖中国的358条勒夫面波路径资料,研究了10.45-113.80s范围内中国西部的三维SH波速度结构.结果表明,各构造单元的SH波速度结构均有明显的差别.作为稳定块体的塔里木盆地,壳内重力分异程度较高,上、中、下地壳厚度差别小,壳内无明显的低速层,地壳平均速度比较小;上地幔低速层埋深大且层中速度大;区内横向变化小.构造活动区如天山、青藏高原,其突出的特征是下地壳厚度大且速度大,上地幔盖层速度值相当高.这与西伯利亚、印支板块的挤压有密切的关系.青藏高原东部及其北、东边缘地区壳内存在低速层,上地幔低速层埋深浅,一些地区存在壳幔过渡层.面波各向异性研究表明,青藏高原、天山及印支板块北缘下存在明显的各向异性,以构造边缘地区及上地幔低速层附近最为突出.印度板块、西伯利亚板块与中国大陆间的碰撞引起强大的水平压力和一定的下插作用,是造成青藏高原隆起、地壳增厚、天山隆起的最根本的因素,同时也促成壳幔中辉石、橄榄石的定向排列和物质运移,因而出现明显的各向异性现象.     

Analysis of the rising and sinking movement of the crust in Qinghai-Xizang Plateau,China

The average swelling height of Qinghai-Xizang Plateau (Tibet) is about 4.1 km. The area is about 2 300 000 km². It is the highest and the largest plateau in the world. Mount Qomolangma, the highest peak in the world, is located in the southern fringe of the plateau, and its height is still increasing. What is the driving force for the rising of the Qinghai-Xizang plateau? How high will the plateau still rise from now on? These questions are much concerned by people. In this paper the distribution of the pressure at different depths in the region of Qinghai-Xizang Plateau are derived according to the three-dimensional structures of the S-wave velocity in the crust and upper mantle. The crust and upper mantle structures of the Qinghai-Xizang Plateau is deliberated on the basis of the distribution with a comprehensive analysis on the rock types, earthquakes and the relative crust movements. Then the two questions raised above are discussed.     

Present-day tectonic movement in the northeastern margin of the Qinghai-Xizang (Tibetan) plateau as revealed by earthquake activity

IntroductionAccording to the division of Neo-tectonically active blocks northeastern Qinghai-Xizang (abbreviated as QX thereafter) plateau is a juncture region where 3 intra-continental subplates, the Qinghai-Xizang, Xinjiang and North China subplate, meet with each other (DING, 1991). The subplates generally consist of blocks. Specifically, around the Yinchuan-Haiyuan (quasi-trijuncture( (TIAN, DING, 1998), where the 3 subplates meet, to the south locates the Gansu-Qinghai (GQ) blo…     

中更新世以来青藏高原RH孔和洛川黄土记录的比较研究

根据若尔盖盆地ＲＨ孔的研究成果,具体地将该孔的２１个阶段和洛川黄土记录进行对比,分析其异同点,探讨了高原不同降升阶段自身环境特点及其对邻近西北干旱区的影响。     

Boundary conditions of the dynamic numerical model for the Chinese mainland lithosphere

The numerical dynamic model of Chinese mainland lithosphere's stress and strain field was constructed with elasto-viscous creep constitutive relation. The most recent data of the stress field of Chinese mainland and the horizontal movement velocity of the crust blocks were used as constraint conditions. The values of the boundary force were computed by trial-and-error method. The effect of the Qinghai-Xizang Plateau's excess potential energy to the movement of Chinese mainland was studied also in this model. The results of the numerical computing show that, recent rapid raising of the Qinghai-Xizang Plateau and the generation of normal faults in the southern part of the plateau resulted from the convergence of Indian Plate to the Eurasian Plate, and also from the rapid convective thinning of the lower lithosphere. Horizontal extension of the Qinghai-Xizang Plateau is the main dynamic factor to form the present tectonic framework of the Chinese mainland. The compressive loads on the eastern boundary of the model were mainly applied by the subduction of the Pacific Plate. The compression from the Philippine Plate maybe slight.     

甘肃天祝现代地壳运动GPS监测网的建立与第一期观测初步结果

本文以ＧＰＳ技术为基础，在位于青藏高原北缘、古浪－海原断裂带的甘肃天视一带布设了现代地壳运动监测网，并完成了第一期观测。初步处理结果表明，ＧＰＳ测量具有高精度，高效率等特点，可以成为监测现代地壳运动的最好方法之一。     

Present-day tectonic movement in the northeastern margin of the Qinghai-Xizang (Tibetan) plateau as revealed by earthquake activity

Characteristics of present-day tectonic movement in the northeastern margin of Qinghai-Xizang plateau (Tibetan) are studied based on earthquake data. Evidence of earthquake activity shows that junctures between blocks in this area consist of complicated deformation zones. Between the Gansu-Qinghai block and Alxa block there is a broad compressive deformation zone, which turns essentially to be a network-like deformation region to the southeast. The Liupanshan region, where the Gansu-Qinghai block contacts the Ordos block, is suffering from NE-SW compressive deformation. Junction zone between the Ordos and Alxa block is a shear zone with sections of variable trend. The northwestern and southeastern marginal region of the Ordos is under NNW-SSE extension. The above characteristics of present-day tectonic deformation of the northeastern Qinghai-Xizang plateau may be attributed to the northeastward squeezing of the plateau and the resistance of the Ordos block, as well as the southeastward extrusion of the plateau materials. Foundation item: State Natural Science Foundation of China (49732090) and the Development Program on National Key Basic Researches under the Project Mechanism and Prediction of Continental Strong Earthquakes (95-13-02-05). Contribution No. 00FE2003, Institute of Geophysics, China Seismological Bureau.     

Review of numerical simulation on the dy-namics of Qinghai-Xizang plateau

IntroductionQinghai-Xizang(QingzangorTibetan)plateauisthemostremarkableactivecollisionbeltontheEarth.Itsaveragealtitudeis5km,itscrustthicknessupto70kmanditsareaabout7?05km2.Inrecenttwentyyears,withthegeophysicalobservationdatagettingmoreandmore,manydy-namicmodelsaboutcrustthickeningandTibetanuplifthavebeenputforward(Harrison,etal,1992;LI,1995;ZENG,etal,1994;ZHONG,DING,1996;XIAO,WANG,1998).Theycanbedividedintotwotypes.ThefirsttypecharacterizesthattheconvergencebetweenIndiaandEura-s…     

Application of the time-frequency polarization analysis to study the complexity of surface wave propagation

A new technique called the time-frequency polarization analysis was introduced in this paper. The technique combined the traditional surface wave analysis techniques (moving window and multi-filter) with the singular value decomposition method to measure the incidence azimuth of surface waves with different wavelengths. It was applied to study the progagation paths of surface waves across the different blocks of Chinese continent and different zones of Qinghai-Xizang (Tibet) plateau. The results show that the method can make full use of the differences in frequency compositions and arrival times of different surface wave modes, and give better polarization analysis results. The analysis by actual data shows that the lateral heterogeneity of the lithospheric structure influences the propagation paths of surface waves severely. Deviations of the paths across the Qinghai-Xizang plateau from great circle paths are great. Deviations of the surface waves across the different zones in Qinghai-Xizang plateau are different. This project was sponsored by the Joint Earthquake Science Foundation.     

喜马拉雅碰撞造山带的深层动力过程与陆─陆碰撞新模型

青藏高原的整体隆升与地壳短缩和其增厚的物理-力学机制是该区深部物质与能量交换,圈、层结构与物质运移及其耦合的产物．印度板块与欧亚板块碰撞的前缘─-喜马拉雅碰撞造山带错综的深层动力过程是本质．基于地震Rayleigh波三维速度结构和人工源深部地震探测结果,发现雅鲁藏布江南北两侧深部构造和地球物理场差异显著,并具有特异的深层动力过程．提出了印度板块地壳和上地幔物质向北"挺进",分别在不同档体阻隔作用下而终止于不同部位的双层"楔板"新模式,在南、北双向挤压力系作用下形成了喜马拉雅碰撞造山带和青藏高原隆升的复杂格局．     

用全球定位系统（GPS）监测青藏高原地壳形变

通过对拉萨、日喀则地区两条基线的观测结果分析，得到了拉萨地块近南北向地壳形变率为（７．０±２．３）ｍｍ／ａ及近东西向（７．４±２．３）ｍｍ／ａ的形变速率，与震源机制解的结论十分接近。同时监测到相对于拉萨南北向７．３ｃｍ和东西向４．１ｃｍ的震后形变位移，显示出ＧＰＳ在地震监测及与地震相关的地壳形变研究的广阔前景     

贡嘎山快速隆升的磷灰石裂变径迹证据及其隆升机制讨论

鲜水河断裂是青藏高原东南缘的一条北西向大型左旋走滑断裂,其南东段逐渐向南偏转,并与近南北向的安宁河断裂相接,在两个断裂相接处西侧耸立着海拔7556 m高的贡嘎山.磷灰石裂变径迹(AFT)测试可知,贡嘎山及其邻区12个样品的年龄分布在0.2±0.1 Ma~2.7±0.7 Ma之间,平均径迹长度在13.64~15.19 μm之间,表明贡嘎山及其邻区第四纪时期一直处于快速剥蚀状态.结合前人在此地区的低温热年代研究成果,揭示出两个现象:(1)贡嘎山岩体及鲜水河断裂与龙门山断裂所夹的三角区域为快速隆升区域,而其西侧、北侧的高原腹地的隆升速率远低于这两个区域;(2)贡嘎山岩体从北向南隆升速率逐渐变大,其最南端1 Ma以来的隆升速率超过3.3±0.8 mm/a.这些现象表明青藏高原在整体横向挤出、缓慢隆升的基础上,还存在着一些特殊的局部快速隆升区域.通过对川滇地块水平运动的矢量分解,我们认为贡嘎山花岗岩体是鲜水河断裂至安宁河断裂间挤压弯曲段吸收、转换川滇地块南东向水平运动导致局部快速隆升的产物,在这一过程中,由于垂直于断裂的挤压分量从北到南逐渐增大,导致了岩体从北往南的隆升速率逐渐增大.     

在重力作用下的我国西南地区地壳物质流

在重力作用下,青藏高原巨厚的地壳成为高原及其邻区现代构造运动的强大动力源。在其驱动下,我国西南地区存在着往南东方向运动的地壳物质流,它具有独特的运动方式,与冰川下滑运动有所不同。在地壳物质流动过程中,由于阻力的差异,可以表现出不同的构造活动性。西南地区地震的发生受到地壳物质流动的控制。西南地区现代构造运动的动力源与重力关系十分密切,因而可属于重力构造范畴     

有关塔波尼亚的青藏高原运动学模型的要点及评述

经过１０多年对青藏高原的野外调查与研究,塔波尼亚提出了青藏高原运动学模型。该文就塔波尼亚的这一模型的主要观点和特色进行了简要的说明,并就若干问题作了评论与讨论。     

青藏高原第五缝合带的发现与论证

１９８７年以来，中国科学院青藏高原综合科学考察队开展了对喀喇昆仑山和昆仑山的多学科综合性科学考察．本文根据这次考察的大量资料，论证了青藏高原第五缝合带的存在．考察资料表明，在西昆仑山存在一个被称作原特提斯的海洋，这个洋是在劳亚大陆南部基底上破裂、扩张并形成于震旦纪至奥陶纪时期（大约８００－４５０Ｍａ）．原特提斯海洋闭合于加里东造山运动，并形成现在所见的库地－苏巴什缝合带的残迹，即青藏高原第五缝合带，从而完善了青藏高原的地质历史和构造演化．