全球五大板块的运动和形变──用卫星激光测距数据导出的站速度分析   总被引：6，自引：2，他引：6       下载免费PDF全文

孙付平  赵铭 《地球物理学报》1994,37(5):596-605

根据德国卫星激光测距（ＳＬＲ）数据分析中心ＧＦＺ对１９８０年１月－１９９１年７月获取的ＳＬＲ观测数据处理后得到的４１个ＳＬＲ站的站速度，解算了北美、欧亚、太平洋、南美和澳大利亚板块之间的相对运动欧拉矢量，得到了第１个ＳＬＲ实测的板块运动模型ＳＰＭＭ１．与地学板块模型ＲＭ２和ＮＵＶＥＬ－１的比较指出，ＳＰＭＭ１大体上与地学模型一致，与ＮＵＶＥＬ－１更为接近；ＳＰＭＭ１的欧亚与北美板块相对运动欧拉极与ＮＵＶＥＬ－１的相应极很接近，但旋转速率明显偏小．还分析了各板块上ＳＬＲ站的局部形变特征．欧亚板块东部和西部存在１０－２０ｍｍ／ａ的相对运动；板块边界附近ＳＬＲ站的残差站速度基本上反映了该边界的构造形变特征．  相似文献   

Relict back-arc basins of Eurasia and their hydrocarbon potentials     

Sergei  Aplonov Kenneth J.  Hsü Vitali  Ustritsky 《Island Arc》1992,1(1):71-77

Abstract Large petroliferous basins in the continental interior are characterized by very thick sedimentary sequences. It is suggested that these are not intracratonic basins, but areas underlain by oceanic crust. These include the Western Siberian, Pre-Caspian, South Caspian, North and South Kara Basins of the Commonwealth of Independent States, and Tarim, junggar and Qaidam Basins of China. The relict ocean basins are distinguished by their basement topography, by their magnetic signatures and by their elevated Moho. Their sedimentary history is distinguished by an abrupt subsidence, followed by isostastic subsidence under sedimentary load. Two circumstances have contributed to the genesis of giant hydrocarbon deposits in these basins: (1) the geochemical environment in those basins was at one time oxygen-deficient as they evolved from the open marine, through restricted marine to become inland alluvial basins; and (2) the sedimentary in-fill provide thick reservoir beds. Oil has accumulated in older structures, folds, faults, unconformities etc. on the margin of the basins, trapping early migrated hydrocarbons.  相似文献   

Late Cenozoic deformation in the South Caspian region: effects of a rigid basement block within a collision zone     

Mark B. Allen  Stephen J. Vincent  G. Ian Alsop  Arif Ismail-zadeh  Rachel Flecker   《Tectonophysics》2003,366(3-4):223-239

Active deformation in the South Caspian region demonstrates the enormous variation in kinematics and structural style generated where a rigid basement block lies within a collision zone. Rigid basement to the South Caspian Basin moves with a westward component relative both to stable Eurasia and Iran, and is beginning to subduct at its northern and western margins. This motion is oblique to the approximately north–south Arabia–Eurasia convergence, and causes oblique shortening to the south and northeast of the South Caspian Basin: thrusting in the Alborz and Kopet Dagh is accompanied by range-parallel strike–slip faults, which are respectively left- and right-lateral. There are also arcuate fold and thrust belts in the region, for two principal reasons. Firstly, weaker regions deform and wrap around the rigid block. This occurs at the curved transition zone between the Alborz and Talysh ranges, where thrust traces are concave towards the foreland. Secondly, a curved fold and thrust belt can link a deformation zone created by movement of the basement block to one created by the regional convergence: west-to-east thrusts in the eastern Talysh represent underthrusting of the South Caspian basement, but pass via an arcuate fan of fold trains into SSW-directed thrusts in the eastern Greater Caucasus, which accommodates part of the Arabia–Eurasia convergence. Each part of the South Caspian region contains one or more detachment levels, which vary dependent on the pre-Pliocene geology. Buckle folds in the South Caspian Basin are detached from older rocks on thick mid-Tertiary mudrocks, whereas thrust sheets in the eastern Greater Caucasus detach on Mesozoic horizons. In the future, the South Caspian basement may be largely eliminated by subduction, leading to a situation similar to Archaean greenstone belts of interthrust mafic and sedimentary slices surrounded by the roots of mountain ranges constructed from continental crust.  相似文献   

First Palaeogene sedimentary rock palaeomagnetic pole from stable western Eurasia and tectonic implications   总被引：1，自引：0，他引：1  

Jason R. Ali  David J. Ward  Chris King  Alexandra Abrajevitch 《Geophysical Journal International》2003,154(2):463-470

  相似文献   

1900年以来全球地震活动的初步分析   总被引：3，自引：2，他引：3  

范洪顺 《国际地震动态》2001,(2):12-18

20世纪50年代和60年代，是全球地震矩的大释放阶段。从60－80年代地震矩释放速率呈下降的趋势。90年代后，地震矩释放速率有所回升。从50－80年代，中国大陆及东半球的地震矩释放速率有明显的下降趋势。一次9级左右地震的成丛是20世纪地震活动的明显特点。  相似文献   

菲律宾海板块与欧亚板块的相互作用及其对东亚构造运动的影响   总被引：18，自引：4，他引：18       下载免费PDF全文

臧绍先  宁杰远 《地球物理学报》2002,45(2):188-197

根据菲律宾海的演化,指出菲律宾海板块的特点:以俯冲边界为主,易于产生形变.将理论结果与地球物理、地质以及GPS测量结果进行比较,发现菲律宾海板块内部及边界有明显形变.讨论了菲律宾海板块与欧亚板块的相互作用,指出其相互作用有明显的分段性.在南海海槽一带有较强的挤压,在琉球海沟一带由于两板块耦合较弱及冲绳海槽的开裂,没有形成对东亚大陆的挤压;台湾附近两板块碰撞,对中国东南形成较强的挤压;在菲律宾群岛一带形成两板块间的复杂变形带,使两板块间的作用减弱.  相似文献   

欧亚大陆春季植被状况与东亚夏季大气环流的显著联系   总被引：1，自引：1，他引：0  

毛睿  龚道溢  CHEN Deliang 《气象学报》2008,66(4):592-598

地表植被覆盖的变化能通过改变陆面参数,以及生地化循环过程,对区域和全球气候产生重要影响.文中利用1982-2002年欧亚大陆春季归一化植被指数(NDVI)和欧洲中期数值天气预报中心再分析资料,采用奇异值分解分析方法,研究欧亚大陆春季植被状况与东亚夏季大气环流的关系.结果表明,贝加尔湖以西区域(55°-65°N,60°-100°E)春季植被状况与东亚夏季大气环流存在显著联系.当春季该区植被指数偏高时,在对流层高层从巴尔喀什湖、贝加尔湖至日本北部,以及中国华南和中南半岛上空存在显著的纬向风正异常,中国华北地区和江淮地区以北为显著负异常,异常中心自北向南依次为"正-负-正"分布,说明东亚夏季200 hPa西风急流轴偏南;相应的在对流层中层15°-25°N地区西风偏强,伴随偏强上升气流,而在25°-42°N地区西风偏弱,并且在32°N附近存在显著下沉气流;在对流层低层,中国江淮流域以北、华北及贝加尔湖以东地区存在明显的反气旋型风场异常,而华南存在东北风异常.这种环流特征说明东亚夏季风偏弱,雨带偏南,并且使得中国华南降水偏多,华南以北大部分地区降水偏少,同时中国东南以及青藏高原东南部温度偏低,而中国北方以及江淮流域温度偏高.欧亚大陆春季植被状况与东亚夏季风的显著关系为东亚夏季风预测提供了有用的帮助.  相似文献   

Post-Soviet urban renewal and its discontents: gentrification by demolition in Baku     

《Urban geography》2012,33(10):1506-1526

ABSTRACT

Gentrification is being increasingly discussed as a driver of urban change globally, including in the former Soviet Union. However, the translation of the gentrification phenomenon into post-Soviet cities like Baku remains poorly understood. This article explores how a particular form of state-led “gentrification by demolition” is unfolding in Baku. We assert the ongoing relevance of using the framework of gentrification to analyze the processes. We go on to use the case of the recently demolished Sovetsky district to carefully expand the geography of the gentrification discourse. We argue that Baku’s own “landscape of gentrification” is shaped by anumber of preconditions. It bears the marks of the legacy of post-socialist cities. However, it more resembles muscular state-led “gentrification by demolition” that is characteristic of Chinese cities. It also echoes Soviet city-building legacies in its use of spectacle and “grand gesture” to legitimize and buy support for gentrification policies.  相似文献   

Paleomagnetism of the Late Cretaceous ignimbrite from the Okhotsk-Chukotka Volcanic Belt,Kolyma-Omolon Composite Terrane: Tectonic implications     

《Journal of Geodynamics》2015

New Late Cretaceous paleomagnetic results from the Okhotsk-Chukotka Volcanic Belt in the Kolyma-Omolon Composite Terrane yield stable and consistent remanent directions. The Late Cretaceous (86–81 Ma) ignimbrites from the Kholchan and Ola suites were sampled at 19 sites in the Magadan area (60.4° N, 151.0° E). We isolated the characteristic paleomagnetic directions from 16 sampled sites using an alternating field demagnetization procedure. The primary nature of these directions is ascertained by dual polarities and positive fold tests. A tilt-corrected mean direction (D = 42.8°, I = 84.7°, k = 46.0, α₉₅ = 10.0°) yields a paleomagnetic pole of 66.7° N, 168.5° E (A₉₅ = 18.8°) which appears almost identical to the 90–67 Ma pole reported from the Lake El’gygytgyn area of the Okhotsk-Chukotka Volcanic Belt (Chukotka Terrane). This consistency suggests that the Kolyma-Omolon Composite Terrane and Chukotka Terrane has acted as a single tectonic unit since 80 Ma without any significant internal deformation. Accordingly, we calculate a combined 80 Ma characteristic paleomagnetic pole (Long. = 164.7° E, Lat. = 68.0°, A₉₅ = 10.9°, N = 12) for the Kolyma-Omolon-Chukotka Block which falls 16.5–17.5° south of the same age poles from Europe and East Asia. We ascribe this discrepancy in pole positions to tectonic activity in the area and infer a southward displacement of 1640 ± 1380 km for the Kolyma-Omolon-Chukotka Block with respect to the North American and Eurasian blocks since 80 Ma; more than 260 km of it is attributed to tectonic displacement in the Arctic Ocean due to the opening of the Canadian Basin.  相似文献   

Geographical extremes in the glacial history of northern Eurasia: post-QUEEN considerations     

Valery Astakhov 《Polar research》2008,27(2):280-288

This paper summarizes the principal results produced by the European Science Foundation's programme, Quaternary Environment of the Eurasian North (QUEEN). These results concern the distribution of late Quaternary glaciers of different ages across northern Eurasia. The pattern of glaciation is compared with the west–east climatic gradient of the continent. Of particular significance is the coincidence of the Late Weichselian ice margin with the modern 30°C difference between the July and January mean air temperatures. The difference between west and east in the annual amplitude of air temperature did not decrease during the Pleniglacial. The asymmetry of the glacial history suggests a progressive aridification of the Eurasian North, with the result that by marine isotope stage 2 significant ice volumes could only accumulate along the Atlantic seaboard. The different climatic signals of thermochrons and cryochrons of the extreme west and east of the continent are discussed. The growth of continentality eastwards restrains the applicability of pollen proxies for climatic reconstructions.  相似文献