华南地块的地极移动曲线及其地质意义   总被引：12，自引：1，他引：12       下载免费PDF全文

林金录 《地质科学》1987,(4):306-315

结合最近获得的古地磁数据,作者重新计算编制了华南地块的地极移动曲线,进而讨论了华南和华北地块在早古生代的地理位置,二者最后拼合的时代,以及华南地块和欧亚大陆北部两条极移曲线之间的系统偏差等问题。  相似文献   

A Review Of Slr Contributions To Geophysics In Eurasia By Cgs     

G. Bianco  R. Devoti  V. Luceri  C. Sciarretta 《Surveys in Geophysics》2001,22(5-6):481-490

In the past 30 years the Satellite Laser Ranging(SLR) technique has improved to a large extent, currently achieving a ranging precision down toa few millimeters. Moreover the growth in the size of the international network of SLR stations and therapidly growing constellation of geodetic target satellites make the SLR a well established technique for solidEarth studies and for the related Earth subsystem sciences. The long SLR observation history has become a veryimportant source of data for global and local changes detection and monitoring in many different fields.Tectonic plate motion, crustal deformation, post-glacial rebound and subsidence, Earth rotation, and polarmotion, time variations of the Earth's gravitational field, ocean tides modeling, center of mass of the totalEarth system monitoring, International Terrestrial Reference System (ITRS) maintenance are only themain applications in which the SLR technique plays a significant role. Plate boundary zones in whichdeformation is diffuse are in general geographical areas associated with high seismic and volcanic activity.A principal key to understand the geophysics of a plate boundary process is the detailed knowledge of the3-D kinematics. This work will focus on the relevant results of the Eurasian SLR subnetwork in termsof technological evolution and crustal deformation. A general overview of the Eurasian SLR stationperformance will be presented with particular reference to the state-of-the-art SLR observatory MLRO (Matera LaserRanging Observatory). The current tectonic deformations (velocity and strain-rate field) detectedby the Eurasian network and by the former WEGENER/MEDLAS campaigns will also be discussed.  相似文献   

Permo–Triassic intraplate magmatism and rifting in Eurasia: implications for mantle plumes and mantle dynamics     

A. M. Nikishin  P. A. Ziegler  D. Abbott  M. -F. Brunet  S. Cloetingh 《Tectonophysics》2002,351(1-2)

At the transition from the Permian to the Triassic, Eurasia was the site of voluminous flood-basalt extrusion and rifting. Major flood-basalt provinces occur in the Tunguska, Taymyr, Kuznetsk, Verkhoyansk–Vilyuy and Pechora areas, as well as in the South Chinese Emeishen area. Contemporaneous rift systems developed in the West Siberian, South Kara Sea and Pyasina–Khatanga areas, on the Scythian platform and in the West European and Arctic–North Atlantic domain. At the Permo–Triassic transition, major extensional stresses affected apparently Eurasia, and possibly also Pangea, as evidenced by the development of new rift systems. Contemporaneous flood-basalt activity, inducing a global environmental crisis, is interpreted as related to the impingement of major mantle plumes on the base of the Eurasian lithosphere. Moreover, the Permo–Triassic transition coincided with a period of regional uplift and erosion and a low-stand in sea level. Permo–Triassic rifting and mantle plume activity occurred together with a major reorganization of plate boundaries and plate kinematics that marked the transition from the assembly of Pangea to its break-up. This plate reorganization was possibly associated with a reorganization of the global mantle convection system. On the base of the geological record, we recognize short-lived and long-lived plumes with a duration of magmatic activity of some 10–20 million years and 100–150 million years, respectively. The Permo–Triassic Siberian and Emeishan flood-basalt provinces are good examples of “short-lived” plumes, which contrast with such “long lived” plumes as those of Iceland and Hawaii. The global record indicates that mantle plume activity occurred episodically. Purely empirical considerations indicate that times of major mantle plume activity are associated with periods of global mantle convection reorganization during which thermally driven mantle convection is not fully able to facilitate the necessary heat transfer from the core of the Earth to its surface. In this respect, we distinguish between two geodynamically different scenarios for major plume activity. The major Permo–Triassic plume event followed the assembly Pangea and the detachment of deep-seated subduction slabs from the lithosphere. The Early–Middle Cretaceous major plume event, as well as the terminal–Cretaceous–Paleocene plume event, followed a sharp acceleration of global sea-floor spreading rates and the insertion of new subduction zone slabs deep into the mantle. We conclude that global plate kinematics, driven by mantle convection, have a bearing on the development of major mantle plumes and, to a degree, also on the pattern of related flood-basalt magmatism.  相似文献   

Eocene Basins on the SE Tibetan Plateau: Markers of Minor Offset along the Xuelongshan–Diancangshan–Ailaoshan Structural System     

LIAO Cheng  YANG Tiannan  XUE Chuandong  LIANG Mingjuan  XIN Di  XIANG Kun  JIANG Lili  SHI Pengliang  ZHU Wenbin  WAN Liangchun  TANG Jing  YU Jing  WU Pinglei 《《地质学报》英文版》2020,94(4):1020-1041

The offset of geological bodies provides robust evidence of displacement along a fault or ductile shear zone. The amount of displacement along the Xuelongshan–Diancangshan–Ailaoshan structural system, southeastern Tibetan Plateau, is uncertain because of the lack of offset geological markers. This NNW–SSE-trending system is developed in three isolated metamorphic complexes and interjacent nonmetamorphosed rocks. They are expected to record similar post-Eocene strain, although their structural patterns should be distinct. Geological mapping in the area between the Xuelongshan and Diancangshan metamorphic complexes has revealed a small Eocene basin, the Madeng Basin, located to the west of the structural system. The sedimentary and volcanic successions of the Madeng Basin are comparable to those of the Jianchuan Basin, which is located to the east of the structural system. Zircon U–Pb geochronological and bulk geochemical data demonstrate that the volcanic rocks of both basins formed during 37–34 Ma and share the same geochemical features. These data suggest that the Madeng and Jianchuan basins previously constituted a single basin, with the distribution of high-K volcanic rocks in the basins defining an ENE–WSW-trending volcanic belt that shows a limited dextral offset of ≤20 km across the Xuelongshan–Diancangshan–Ailaoshan structural system. Therefore, the northern segment of the structural system records no evidence of large-scale lateral movement/displacement. The results suggest that the Indochina block, which is bounded by the Xuelongshan–Diancangshan–Ailaoshan structural system to the east and the Sagaing Fault to the west, has not extruded southward as a whole but rather has been deformed by pervasive crustal shortening.  相似文献   

Inhomogeneities of the Eurasian mantle structure from the traveltimes of the nuclear explosions recorded by the Finnish seismic network during 1961–1985     

M. Grad  M. Krzy&#;anowska  S. E. Pirhonen 《Geophysical Journal International》1995,121(3):863-872

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欧亚大陆风云影像线性构造信息提取及其地质分析   总被引：2，自引：1，他引：1  

杨巍然  隋志龙 《地学前缘》2004,11(4):551-558

通过欧亚大陆风云影像的空间增强、光谱增强、辐射增强等系列处理和地质解释 ,提取了发育于该区的各种线性构造的相关信息。根据性质和规模将线性构造划分为大洋俯冲带、大陆俯冲带、大陆碰撞带、巨型线性构造、区域线性构造和局部线性构造等六类。文中重点介绍了乌拉尔—阿曼巨型线性构造带和阿尔卑斯大陆碰撞带的影像特征和地质意义。根据各类线性构造的特征和相互关系 ,突出了乌拉尔—阿曼和伊尔库茨克—横断山两条巨型线性构造带的地位 ,并以它们为界划分了三个构造域 :西亚构造域以印度板块的俯冲为特色 ,导致青藏高原的隆升和陆内强烈变形 ;东亚构造域最为重要的特征是太平洋板块的俯冲 ,形成一系列岛弧体系 ,并使大陆内部出现大量岩浆活动和强烈的构造变动 ;欧洲构造域主要为非洲—阿拉伯板块与欧洲板块的碰撞 ,二者之间没有明显的俯冲带 ,而有一个较宽广的接触带 ,强烈的变形集中在这一带内 ,而大陆内部的构造变动比较微弱。这种构造格局在欧亚大地水准面异常图上有明显反映 ,表明与深部地质作用过程有关。三个构造域的主导线性构造的方向组成了一个向南弯曲的弧形 ,弧顶位于西亚构造域。大陆巨型线性构造带呈经向和纬向展布 ,具长期发育特征 ,从更大尺度上看 ,板块边界线性构造也是呈经向和纬?  相似文献   

欧亚北部2004年以来频繁冷冬的特征分析及机理初探   总被引：2，自引：0，他引：2  

乔少博  沈柏竹  王晓娟  封国林 《气象学报》2014,72(6):1143-1154

利用1961—2013年NCEP/NCAR发布的月平均全球再分析资料,分析了欧亚北部(40°65°N,50°-120°E)2004年以来频繁冷冬的异常特征及形成机理。结果表明:欧亚北部2004年以来冷冬频繁发生,但温度异常的空间分布,尤其中心冷区的位置有显著差异,主要表现为全区偏冷型(2005、2009、2010、2012年)和南部偏冷型(2004、2007、2011年)。全区偏冷年主要由北极涛动(AO)显著负位相所致,对应海表温度特征为北大西洋高、中、低纬度成东北-西南走向的"+、-、+"带状分布,该分布有利于北极涛动/北大西洋涛动(AO/NAO)负位相维持和增强;南部偏冷年大气内部活动异常为乌拉尔-贝加尔湖阻塞高压偏强,北极涛动/北大西洋涛动以弱正位相为主,对应主要海表温度特征为北大西洋中部偏高,其次则为太平洋年代际振荡(PDO)负位相下"类拉尼娜事件",上述海表温度异常均可促进类似欧亚遥相关的罗斯贝波列形成,有利于乌拉尔贝加尔湖阻塞高压偏强、亚洲中部多低槽活动。2004年以来欧亚北部两种类型冷冬的大气环流与海表温度均表现出与历史典型年相类似的特征。  相似文献   

冬季欧亚海平面气压场主要空间模态的年代际变化特征     

杨秋明 《气候变化研究进展》2008,4(4):240-244

 运用非线性主成分分析法对欧亚地区1948-2007年冬季海平面气压距平场进行分析。结果表明：冬季欧亚地区海平面气压异常变率具有显著的非线性特征,当非线性主成分取不同的异常值时,对应的空间气压异常分布型具有显著的非对称性。同时,第一非线性模态（NLPC1）年际振荡强度和周期在20世纪70年代初存在明显的年代际变化,1970年以后,年际振荡强度显著增强。  相似文献   

冬季欧亚海平面气压场主要空间模态的年代际变化特征     

杨秋明 《气候变化研究进展》2008,4(04):240-244

运用非线性主成分分析法对欧亚地区1948-2007年冬季海平面气压距平场进行分析。结果表明：冬季欧亚地区海平面气压异常变率具有显著的非线性特征,当非线性主成分取不同的异常值时,对应的空间气压异常分布型具有显著的非对称性。同时,第一非线性模态（NLPC1）年际振荡强度和周期在20世纪70年代初存在明显的年代际变化,1970年以后,年际振荡强度显著增强。  相似文献   

Establishment of regional reference frames for quantifying active deformation areas in Anatolia     

Bahadir Aktuğ  Ali Kiliçoğlu  Onur Lenk  Mehmet A. Gürdal 《Studia Geophysica et Geodaetica》2009,53(2):169-183

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