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Apatite fission track dating evidence on the tectonization of Gangdese block. south Qinghai-Tibetan Plateau

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Chinese Science Bulletin 2002年第3期47卷 239-243页

作者： YUAN Wanming WANG Shicheng LI Shengrong YANG Zhiqiang Institute of High Energy Physics Chinese Acadeny of SciencesBeijing 100039China China University of Geosciences Beijing 100083China Exploration and Production Research Institute SINOPECBeijing100083China

This work makes the quantitative constrain on tectonizations of the Gangdese block. south Qinghai-Tibetan Plateau. Apatite fission track (AFT) dating analyses of 15 samples collected across the Gangdese block.show that the Gangdese block.went through two periods of tectonizations, during -37.2-18.5 Ma and 18.5 - 8.0 Ma in the south Gangdese block. and during -47.6-5.3 Ma and 5.3-0 Ma in the middle Gangdese block. Different upliftings did not take place in the first period and rapid uplifting occurred in the late period. Meantime, there are some differences be-tween the south and middle Gangdese block. Their uplifting rate is 180 m/Ma and 70 m/Ma respectively. The rapid up-lifting time in the middle Gangdese block.lagged behind the time in the south Gangdese block. It is Chala-Jiacuo-Riduo fault zone that is similar to the Yarlung Zangbo fault zone in control of the tectonization.

关键词： tectonization fault zone fission track apatite uplifting and cooling Gangdese block.

Revised apparent polar wander path of the Yangtze block.and its tectonic implications

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Science China Earth Sciences 1998年第S2期41卷 78-90页

作者：吴汉宁朱日祥白立新郭斌吕建军 Department of Geology Northwest University Xi’an China Institute of Geophysics Chinese Academy of Sciences Beijing China

Paleomagnetic data, during the Phanerozoic obtained in the last 20 years in the Yangtze block.(YZB), are critically reviewed. A new apparent polar wander path (APWP) for the YZB is constructed by selected poles with objective reliable criteria, with a goal of placing constraints on the models of the formation and subsequent deformation and reconstructing the tectonic evolution history of this region

关键词： paleomagnetism apparent polar wander path Yangtze block.

The history of crustal uplift and metamorphic evolution of Panzhihua-Xichang micro-palaeoland, SW China:Constraints on Sm-Nd, ^(40)Ar/^(39)Ar and FT ages of granulites

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Science China Earth Sciences 2004年第8期47卷 689-703页

作者： XU Shijin1, LIU Wenzhong1, WANG Rucheng1, YU Hangbo1, LI Daming2, WAN Jinglin2 & FANG Zhong1 1. Department of Earth Sciences and State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210093, China 2. Institute of Geology, China Seismological Bureau, Beijing 100029, China 1. Department of Earth Sciences and State Key Laboratory for Mineral Deposits Research Nanjing University 210093 Nanjing China 2. Institute of Geology China Seismological Bureau 100029 Beijing China

Panzhihua-Xichang (Panxi) micro-palaeoland is the oldest terrane on the western margin of the Yangtze block. Some intermediate-basic granulites are considered to be the crys-talline basement of lower crust in the terrane. Granulite-facies metamorphism of the granulites was developed in the period from 1186 Ma to 1128 Ma. The origin of granulites was related to the collision orogenic process occurring when the micro-palaeolands merged to form the Rodinia Supercontinent. Amphibolite-facies retrogressive metamorphism of granulites took place in the period from 877 Ma to 825 Ma. This period was consistent with the breakup time of the Rodinia Supercontinent. 40Ar/39Ar ages and fission track (FT) ages of granulites in the Panxi mi-cro-palaeoland show that the vertical movement history of crustal rocks was a slow uplift process of the rigid terrane in the time from Neoproterozoic to Mesozoic. The subduction of India Plate towards Euroasia Plate resulted in the rapid uplift of the Qinghai-Tibetan block.in Cenozoic. Meanwhile, the Qinghai-Tibetan block.moved towards east. Consequently the Panxi terrane was uplifted rapidly. As a result of the collision orogeny between the Qinghai-Tibetan block.and the Panxi terrane, the granulite-facies crystalline basement in this region was exhumed and exposed to the surface.

关键词： granulite,isotope geochronology,crustal uplift movement,Panzhihua-Xichang region,western margin of Yangtze block.

Late Cenozoic deformation subsequence in northeastern margin of Tibet --Detrital AFT records from Linxia Basin

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Science China Earth Sciences 2003年第z2期46卷 266-275页

作者： ZHENG Dewen (郑德文) ZHANG Peizhen (张培震) WAN Jinglin (万景林) LI Chuanyou (李传友) CAO Jixiu (曹继秀) Institute of Geology China Seismological Bureau Beijing 100029 China Institute of Geology China Seismological Bureau Beijing 100029 China Institute of Geology China Seismological Bureau Beijing 100029 China Institute of Geology China Seismological Bureau Beijing 100029 China Department of Geology Lanzhou University Lanzhou 730000 China

Two events of Tibet uplifting are revealed by detrital apatite fission track (AFT) age data from Linxia Basin. They occurred at about 14 and 5.4-8.0 MaBP respectively. We interpret the first one to be related to the uplifting of the northern Tibet, which might have resulted from convectively removing the thickened lower lithosphere. The second one is a result of Laji Mountain uplifting. Numerous studies of the Tibetan Plateau suggest that the onset time of the deformation in the northeastern margin of Tibetan Plateau and the time of Tibet attaining to its present elevation is about 8 MaBP. They are approximately coincident with the uplift of Lajishan Mountain. It suggests that the northeastern margin of Tibet propagated northeastwardly to its present site in about 8 MaBP for accommodating the sustained convergence between India-Eurasia plate and for keeping its high elevation. The active block.pattern dominating the strong earthquake distribution of Chinese continent probably formed at about 8.0-5.4 MaBP.

关键词： Linxia Basin, detrital apatite fission track, tectonic event, active block.

Numerical simulations of deformation and movement of block. within North China in response to 1976 Tangshan earthquake

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Science China Earth Sciences 2003年第z2期46卷 141-152页

作者： BAI Wuming (白武明) LIN Banghui (林邦慧) CHEN Zu'an (陈祖安) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geophysics China Seismological Bureau Beijing 100081 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Using methods of discontinuous deformation analysis and finite element (DDA+FEM), this paper simulates dynamic processes of the Tangshan earthquake of 1976, which occurred in the northern North China where its internal block. apparently interacted. Studies focus upon both the movement and deformation of the block., in particular, the Ordos block. and variations of stress states on the boundary faults. The Tangshan earthquake was composed of three events: slipping motions of NNE-striking major fault, NE-striking fault near the northeastern end of the NNE-striking fault, and NW-striking fault on the southeastern side of the NNE-striking fault. Compared with previous studies, our model yields a result that is more agreeable with the configuration of aftershock distributions. A number of data are presented, such as the principle stress field during the earthquake, contours of the maximum shear stress, the strike-slip deformation between block. near the earthquake focus, time-dependent variations of slips of earthquake-triggered faulting, the maximum slip distance, and stress drops. These results are in accord with the earthquake source mechanism, basic parameters from earthquake wave study, macro-isoseismic line, observed horizontal displacement vectors, etc. The Tangshan earthquake exerted different influences on the adjacent block. and boundary faults between them, thus resulting in differential movement and deformation. The Ordos block.seems to have experienced the small-scale counterclockwise rotation and deformation, but its northeast part, bounded on the east by the Taihangshan and on the north by the Yanshan and Yinshan belts, underwent relatively stronger deformation. The Tangshan earthquake also changed the stress state of boundary faults of the North China, leading to an increase in shear stress and a decrease in normal stress in the NW-trending Zhangjiakou-Penglai fault through Tangshan City and the northern border faults of the Ordos block. and therefore rai

关键词： discontinuous deformation analysis, Tangshan earthquake, deformation and movement of block.

S-wave velocity and Poisson's ratio structure of crust in Yunnan and its implication

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Science China Earth Sciences 2005年第2期48卷 210-218页

作者： HU Jiafu, SU Youjin, ZHU Xiongguan & CHEN Yun Geophysical Department of Yunnan University, Kunming 650091, China Seismological Bureau of Yunnan Province, Kunming 650041, China Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China 1. Geophysical Department of Yunnan University 650091 Kunming China 2. Seismological Bureau of Yunnan Province 650041 Kunming China 3. Institute of Geology and Geophysics Chinese Academy of Sciences 100101 Beijing China

Receiver function of body wave under the 23 stations in Yunnan was extracted from 3-component broadband digital recording of teleseismic event. Thus, the S-wave velocity structure and distribution characteristics of Poisson's ratio in crust of Yunnan are obtained by inversion. The results show that the crustal thickness is gradually thinned from north to south. The crustal thickness in Zhongdian of northwest reaches as many as 62.0 km and the one in Jinghong of further south end is only 30.2 km. What should be especially noted is that there exists a Moho upheaval running in NS in the Chuxiong region and a Moho concave is generally parallel to it in Dongchuan. In addition, there exists an obvious transversal inhomogeneity for the S-wave velocity structure in upper mantle and crust in the Yunnan region. The low velocity layer exists not only in 10.0-15.0 km in upper crust in some regions, but also in 30.0-40.0 km in lower crust. Generally, the Poisson's ratio is on the high side, however it has a better corresponding relation to the crustal velocity structure. An obvious block.distribution feature is still shown on such a high background of Poisson's ratio. It is discovered by synthetically analyzing the velocity structure and Poisson's ratio distribution that there are high Poisson's ratio and complicated crust-mantle velocity structure feature in the Sichuan-Yunnan Diamond block.with Xiaojiang fault to be the east boundary and Yulong Snow Mountain fault to be the west boundary besides the frequent seismicity. This feature differs obviously from that of surrounding areas, which would provide geophysical evidence to deeply study the eastwardly flowage of lithospheric substances in the Qinghai-Tibet Plateau.

关键词： Yunnan, S-wave velocity, Poisson's ratio, Sichuan-Yunnan Diamond block.

Paleomagnetic results of Paleozoic and Mesozoic rocks from Xingshan-Zigui section in Hubei Province, South China

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Science China Earth Sciences 1999年第2期42卷 182-194页

作者：吴汉宁朱日祥白立新邢建孝赵永新杨革联 1. Department of Geology Northwest University 710069 Xi’an China 2. Institute of Geophysics Chinese Academy of Sciences 100101 Beijing China 3. Institut de Physique du Globe de Paris 75252 Paris France

The paleomagnetic reconnaissance study of the Paleozoic and Mesozoic sedimentary rocks from the Yangtze block.(YZB) was made to conduct the Apparent Polar Wander Path (APWP) of the YZB during the Phanerozoic. A total of 825 samples from 84 sites were collected from a continuous section along the Xiangxi River valley in Xingshan and Zigui counties in Hubei Province, northern margin of the YZB. Stepwise thermal/alternating demagnetization isolated well defined characteristic magnetization (ChRM) at a higher temperature in most of the samples, and relatively thermal stability and high coercivity were revealed from these samples. All the ChRMs can pass the fold and/or reversal tests, suggesting that they are probably primary. Therefore, new pole positions are presented for the YZB.

关键词： paleomagnetism Apparent Polar Wander Path Paleozoic Mesozoic Yangtze block.

PALEOMAGNETIC RESULTS FROM THE LATE PERMIAN REDBEDS ALONG THE HEXI CORRIDOR, CHINA

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Chinese Science Bulletin 1992年第17期37卷 1452-1456页

作者：孟自芳 Lanzhou Institute of Geology Academia Sinica Lanzhou 730000 PRC

In an attempt to paleomagnetically ascertain the tectonic ownership of the Hexi Corridor during the Late Permian, we collected 98 oriented cores with a portable drilling apparatus from two type sections along the corr... 详细信息

关键词： the Hexi Corridor the Late Permian western extension of North China block.

PRELIMINARY PALEOMAGNETIC EVIDENCE FOR EARLY TRIASSIC SEPARATION OF THE HUANAN AND YANGTZE block., SOUTH CHINA

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Chinese Science Bulletin 1992年第15期37卷 1297-1301页

作者：陈海泓孙枢李继亮 KENNETH J. HSU FRIEDRICH HELLER JON DOBSON Laboratory of Lithosphere Tectonic Evolution Institute of Geology Academia Sinica Beijing 100029 PRC Swiss Federal Institute of Technology CH-8092 Zurich

South China comprises three distinct lithospheric block., namely the Yangtze, Huanan and Dongnanya (Southeast Asia) block. according to the hypothesis of 'Mesozoic collisional orogenies of South China' . The Yangtze a... 详细信息

关键词： paleomagnetism early Triassic Huanan block Yangtze block.