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Contemporary crustal movement of continental china obtained by global positioning system(GPS) measurements

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Chinese Science Bulletin 2001年第18期46卷 1552-1554,1588页

作者： MA Zongjin, CHEN Xinlian, YE Shuhua, LAI Xian, WEI Ziqing, CHEN Junrong, NING Jinsheng, XU Huoze & DING Guoyu1. Insitute of Geology, china seismological bureau, Beijing 100029, china (e-mail: disgroup@***)2. Center for Analysis and Prediction, china seismological bureau, Beijing 100036, china 3. Shanghai Astronomic Observatory, Chinese Academy of Sciences, Shanghai 200030, china 4. institute of seismology, china seismological bureau, wuhan 43.077, china 5. institute of Survey and Mapping, Xi’an 710054. china 6. National bureau of Survey and Mapping, Beijing 100830, china 7. wuhan University, wuhan 43.077, china 8. institute of Geodesy and Geophysics, wuhan 43.077, china 9. china seismological bureau, Beijing 100036, china Insitute of Geology China Seismological Bureau Beijing China Center for Analysis and Prediction China Seismological Bureau Beijing China Shanghai Astronomic Observatory Chinese Academy of Sciences Shanghai China institute of seismology China Seismological Bureau Wuhan China institute of Survey and Mapping Xi’an China National bureau of Survey and Mapping Beijing China wuhan University Wuhan China institute of Geodesy and Geophysics Wuhan China china seismological bureau Beijing China

We obtain a unified horizontal velocity field of continental china and vicinity through measurements at 81 GPS stations provided by the National Key Infrastructure Project, Crustal Movement Observation Network of china. The velocity field delineates patterns of movements and deformation of active crustal blocks in continental china under the Eurasia-fixed reference frame. The space-based geodesy also clearly shows for the first time the horizontal movementand deformation of continental china induced by indentation of the Indian plate. The data provide kinematic constraints for simulating dynamic process of continental litho-spheric deformation.

关键词： crustal movement velocity field tectonic deformation.

Experimental study of ore gabbro liquid immiscibility

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Science china Earth Sciences 2005年第4期48卷 496-505页

作者： SANG Zunan1,2, XIA Bin1, ZHOU Yongsheng3 & JIN Zhenmin4.1. Guangzhou institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 51064., china 2. wuhan University, wuhan 4.0072, china 3. institute of Geology, china seismological bureau, Beijing 100029, china 4. Faculty of Earth Sciences, china University of Geosciences, wuhan 4.0074. china Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou China wuhan University Wuhan China institute of Geology China Seismological Bureau Beijing China Faculty of Earth Sciences China University of Geosciences Wuhan China

In this paper, the authors present the results of a preliminary experimental study on partial melting of fine-grained gabbro, Panzhihua, Sichuan Province, china. Experiments were conducted under (confining) pressure ranging from 4.0 to 500 MPa and temperature of 900— 1200℃. The results show that the initial melt is distributed along grain boundaries and triple junctions. Liquid immiscibility phenomena are noted in the melt with two compositional different melt phases, i.e. matrix and sphere phases. The matrix phase is relatively rich in Si, Al and K, and is depleted in Mg, Fe, Ca, Na and Ti, whereas the sphere phase shows opposite trends. The calculation of the melt free energy indicates that the liquid immiscibility is governed by the rule of thermodynamics, as the liquid immiscibility would result in the decrease in free energy of the melt system. The field relationships suggest that the liquid immiscibility may have played an important role in the generation of ore magma of Panzhihua V-Ti magnetite ore deposit. This study thus provides experimental constraints on the mechanism of the formation of V-Ti magnetite deposite.

关键词： partial melting, experimental study, gabbro, liquid immiscibility, ore formation mechanism.

Partial Melting and Its Implications for Understanding the Seismic Velocity Structure within the Southern Tibetan Crust

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Acta Geologica Sinica(English Edition) 2003年第1期77卷 64-71页

作者： YANG Xiaosong, MA Jin, JIN Zhenmin, GAO Shan and MA Shengli Geology institute, china seismological bureau, Beijing 100029 Laboratory of Tectonophysics, china seismological bureau, Beijing 100029 Faculty of Earth Sciences, china University of Geosciences, {4., Hubei 4.0074 china Seismol Bur Inst Geol Beijing 100029 Peoples R China china Seismol Bur Lab Tectonophys Beijing 100029 Peoples R China china Univ Geosci Fac Earth Sci Wuhan 430074 Hubei Peoples R China

In order to constrain the crustal wave velocity structure in the southernTibetan crust and provide insight into the contribution of crustal composition, geothermal gradientand partial melting to the velocity structure, which is characterized by low average crustalvelocities and widespread presence of low-velocity zone(s), the authors model the crustal velocityand density as functions of depth corresponding to various heat flow values in light of velocitymeasurements at high temperature and high pressure. The modeled velocity and density are regarded ascomparison standards. The comparison of the standards with seismic observations in southern Tibetimplies that the predominantly felsic composition at high heat flow cannot explain the observedvelocity structure there. Hence, the authors are in favor of attributing low average crustalvelocities and low-velocity zone(s) observed in southern Tibet mainly to partial melting. Modelingbased on the experimental results suggests that a melting percentage of 7-12 could account for thelow-velocity zone(s).

关键词： partial melting intracrustal low-velocity zone high-pressure andhigh-temperature experiments Tibetan plateau

The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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Science china Earth Sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2, TENG Jiwen1, Lü Qingtian3, LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4.1. institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china 2. institute of Geophysics, china seismological bureau, Beijing 100085, china 3. institute of Deposition Resource, Chinese Academy of Geosciences, Beijing 100037, china 4. School of Exploration and Information, china University of Geosciences, Beijing 100083, china institute of Geology and Geophysics Chinese Academy of Sciences Beijing China institute of Geophysics China Seismological Bureau Beijing China institute of Deposition Resource Chinese Academy of Geosciences Beijing China School of Exploration and Information China University of Geosciences Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2 km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2 segments. In the studied area, crustal thickness is about 4. km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

Age of Yingfeng rapakivi granite pluton on the north flank of Qaidam and its geological significance

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Science china Earth Sciences 2004年第4期47卷 357-365页

作者： XIAO Qinghui1,2, LU Xinxiang1,3, WANG Fei4. SUN Yangui5, WEI Xiangdong3 & XING Zuoyun6 1. Division of Granite Geology, china Geological Survey, Yichang 4.3003, china 2. Information Center of Ministry of Land and Resources, Beijing 100812, china 3. Geological Survey of Henan Province and institute of Geological Research of Henan Province, Zhengzhou 4.0053, china 4. Geological institute, china seismological bureau, Beijing 100029, china 5. Geological Survey institute of Qinghai Province, Xining 810032, china 6. china University of Geosciences, wuhan 4.0074. china Division of Granite Geology China Geological Survey Yichang China Information Center of Ministry of Land and Resources Beijing China Geological Survey of Henan Province and institute of Geological Research of Henan Province Zhengzhou China Geological institute China Seismological Bureau Beijing China Geological Survey institute of Qinghai Province Xining China china University of Geosciences Wuhan China

The Yingfeng rapakivi granite on the north flank of Qaidam is a newly discovered Proterozoic rapakivi pluton in china, which was found after the discovery of Shachang rapakivi in Miyun County, Beijing and Kuandian rapakivi in Jilin Province. Yingfeng rapakivi pluton is ex-posed on the north side of the suture belt between Qinling-Kunlun orogenic belt and North china plate. U-Pb zircon isotopic dating and Ar-Ar isotopic dating of both hornblende and K-feldspar from the Yingfeng rapakivi granite have been conducted. The results show that the age of (1776±33)Ma at the upper intercept in Concorde diagram represents the age of formation of the plu-ton, whereas the age of (526 281) Ma at the lower intercept and Ar-Ar mineral dating of horn-blende and K-feldspar correspond to the age of a later event affecting the pluton, suggesting that Yingfeng pluton has ever been affected by strong regional Caledonian-Hercynian tectonic movement after its formation. The discovery of middle Proterozoic Yingfeng rapakivi granite pro-vides a petrologic evidence for the timing of cratonization of both the continental crust basement in western china and the basement of the North china plate and for a rifting event taking place in the mid-Proterozoic, suggesting that an amalgamation of ancient china continents had ever happened during the L liang Movement?between the early Proterozoic and the mid-Proterozoic.

关键词： rapakivi, U-Pb dating, Ar-Ar dating, Kunlun-Qinling orogenic belt.

δD values of escaped H_2 from hot springs at the Tengchong Rehai geothermal area and its origin

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Chinese Science Bulletin 2002年第2期47卷 146-149页

作者： SHANGGUAN Zhiguan & HUO Weiguo institute of Geology, china seismological bureau, Beijing 100029, china institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china institute of Geology China Seismological Bureau Beijing 100029 China

Here we give the δD values of escaped H2 from hot springs at the Tengchong Rehai and adjacent regions, and deal with a genetic correlation between the increment H2 in escaped gases from middle-shallow reservoirs and the H2S, CH4.derived from deep sources. Isotopic compositions of H2 indicate that the generation of increment H2 may be related to recent strong activity of N-W trending fault at the Rehai area. Trace monitoring the H2 release could be significant in order to keep watch on present activity of that fault.

关键词： Rehai geothermal area hydrogen stable isotopic composition.

Lithosphere types in North china:Evidence from geology and geophysics

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Science china Earth Sciences 2005年第11期48卷 1809-1827页

作者： QIU Ruizhao1,2, DENG Jinfu3, ZHOU Su3, LI Jinfa4. XIAO Qinghui1,5, WU Zongxu6 & LIU Cui3 1. institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, china 2. Development and Research Center, china Geological Survey, Beijing 100037, china 3. china University of Geosciences, Beijing 100083, china 4. china University of Geosciences, wuhan 4.0074. china 5. Information Center of Ministry of Land and Resources, Beijing 100812, china 6. institute of Geology, State seismological bureau, Beijing 100029, china institute of Geology Chinese Academy of Geological Sciences Beijing China Development and Research Center China Geological Survey Beijing China china University of Geosciences Beijing China china University of Geosciences Wuhan China Information Center of Ministry of Land and Resources Beijing China institute of Geology State Seismological Bureau Beijing China

On the basis of the characteristics of geology and geophysics in North china, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North china platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North china Platform is a remnant of cratonic lithosphere after the North china platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North china craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North china platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North china in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the

关键词： lithospheric types,evidence of geology and geophysics,crust-mantle petrological structure,deep process

DYNAMIC STRESS CONCENTRATION AROUND A CIRCULAR HOLE DUE TO SH-WAVE IN ANISOTROPIC MEDIA

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Acta Mechanica Sinica 1988年第2期4卷 146-155页

作者： Liu Diankui, institute of Engineering Mechanics, State seismological bureau, Harbin, china institute of Engineering Mechanics State Seismological Bureau Harbin China

A new approach based on complex function to solve the SH-wave scattering problemaround a circular hole in anisotropic media is introduced in this paper. It is found that the dynamicstress concentration factor is dependent on the incident wave number and the hole radius. Finally,some numerical results of dynamic stress concentration factor of a circular hole in anisotropic mediaare given.

关键词： SH-wave scattering of elastic wave dynarnic stress concentration sleady-state wave

THE GLOBAL TECTONIC SYSTEMS AND A LATITUDINAL MOUNTAIN-PLATEAU CHAIN ON THE NORTH HEMISPHERE

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地学前缘 2000年第S1期7卷 344-345页

作者： Ma Zongjin(institute of Geology,china seismological bureau,Beijing 100029,china)

Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific tectonic system,the mid\|ocean ridge tectonic system and the intra\|continental tectonic system of the north *** map shows that about 80% of the total length of the continental orogens are concentrate on the north hemisphere of the earth,of which a latitudinal mountain\|plateau chain occur within a zone between north latitude 20°and 50°.Seismic and volcanic activities demonstrate that the intracontinental tectonic system on the north hemisphere is still *** distribution of the continental deep\|focus earthquakes and almost ultra high\|pressure rock found so far over the World,that are assumed both related to recent or previous deep subduction of continent,along with this *** latitudinal mountain\|plateau chain is subdivided into four active tectonic region of Qinghai—Xizang(Tibet),Iranian,eastern mediterranean and North American,both characterized by an individual similar mountain\|plateau\|basin structure with major active boundaries or controlling faults (Fig.1).These active regions are all close to primary dynamic boundaries of continent\|continent *** of source mechanisms shows that regional tectonic stress field in these regions are dominated by a nearly NS or NNE—SSW direction compression corresponding to a local plate motions and a global compressive *** between the formation of the continental latitudinal mountain\|plateau chain on north hemisphere and the oceanic plate tectonics is discussed using the information of the “Map of Magnetic Lineations of the World’s Ocean Basins (Cande et al.,1989)”and the Cenozoic and Mesozoic tectonic evolution in the *** 4. accretion units formed during 6 accretion stages of the ocean spreading in three chief oceans (the Pacific,the India and th

关键词： global asymmetrical system geodynamics mountain\| plateau chain seismotectonic system latitudinal tectonic zone