检索结果-南通市图书馆

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 {3. of earth sciences, china university of geosciences, wuhan, hubei 43.074 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

Experimental study of ore gabbro liquid immiscibility

在线全文

学校读者我要写书评

暂无评论

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 510640, china 2. wuhan {3., wuhan 43.072, china 3. Institute of Geology, china seismological bureau, Beijing 100029, china 4. faculty of earth sciences, china university of geosciences, wuhan {13., 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 450 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.

^(40)Ar-^(3.)Ar and U-Pb ages of metadiorite from the East Kunlun Orogenic Belt: Evidence for Early-Paleozoic magmatic zone and excess argon in amphibole minerals

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2001年第4期46卷 330-333页

作者： CHEN Nengsong, SUN Min, ZHANG Kexin & ZHU Yunhaifaculty of earth sciences,{3., wuhan 43.074, china Department of earth sciences, The university of Hong Kong, Hong Kong SAR, china faculty of earth sciences China University of Geosciences Wuhan China Department of earth sciences The University of Hong Kong Hong Kong SAR China

Single-grain zircon U-Pb and amphibole 40Ar-3.Ar dating have been conducted on a deformed and metamorphosed diorite in the East Kunlun Orogenic Belt, which intruded into the middle Proterozoic Kuhai Group exposed in the south of Xiangride region, Dulan County, NW Qinghai Province. The zircon gives a concordant U-Pb age of (446.5±9.1) Ma. The amphibole yields Ar plateau age of (488.0±1.2) Ma and an isochronal age of (488.9±5.6) Ma. Age results of both stepwise released Ar and conventional K-Ar analysis are remarkably higher than that of zircon U-Pb, suggesting that the amphibole contains excess argon and the amphibole plateau age cannot be taken as the timing of metamorphism or deformation. The zircon age is interpreted to be crystallization age of the diorite pluton, which suggests that an Early-Paleozoic magmatic zone indeed existed in the East Kunlun Orogenic Belt stretching along the region south to the Golmud, Normuhong and Xiangride.

关键词： East Kunlun Orogenic Belt metadiorite geochronology excess argon.

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

在线全文

学校读者我要写书评

暂无评论

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 10003., 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 40 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.

Lithosphere types in North china:Evidence from geology and geophysics

在线全文

学校读者我要写书评

暂无评论

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 10003., china 2. Development and Research Center, china Geological Survey, Beijing 10003., china 3. china university of geosciences, Beijing 100083. china 4. china university of geosciences, wuhan 43.074, 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

New Paleomagnetic Study on Early Triasic Liujiagou Formation of Northchina Block

在线全文

学校读者我要写书评

暂无评论

Journal of earth Science 1998年第3期17卷 60-61页

作者： Tian Wuhong faculty of earth sciences,{3., wuhan 43.074 Niu Xiukai Hebei bureau of Geology and Mineral Resources, Shijiazhuang 050081

This paper introduces the result of studying on paleomagnetism of 91 specimens from 13.sites from Liujiagou Formation in Dashu Village, Wu ’an city, Hebei Province. The result reveals that North china block (NCB) was not united with Yangtze block (YB) in the Early Triassic. From the Early Triassic to now, NCB has rotated 3..0° counterclockwise, but YB has rotated 45.1° clockwise.

关键词： Liujiagou Formation paleomagnetism Early Triassic North china block.

Tectonic Characteristics and Emplacement Mechanism of Dayishan Granite in Hunan Province, china

在线全文

学校读者我要写书评

暂无评论

Journal of earth Science 1999年第4期18卷 287-290页

作者： Li Xianfu(wuhan Institute of Chemical Technology, wuhan 43.073.Li Jianwei Fu Zhaoren Li Zijin(faculty of {3. sciences, china university of geosciences, wuhan 43.074) wuhan Institute of Chemical Technology Wuhan 430073 faculty of earth sciences China University of GeosciencesWuhan 430074

Dayishan granite, a significant metallogenic-rock body located in Shaoyang-Chenxian tectonomagmatic belt of Hunan Province, was controlled by 'Dayishan-type' fault pattern. Based on the study of tectonic setting and geological features of the grantie, it is concluded that the tectonic system controlling magmatic emplacement is a shear folded-fauted zone which resulted from NW-trending convergent strike-slip faulting. The close relationship between the temporal-spatial distribution, emplacement mechanism of Dayishan granite and the strike-slip faulting is detailed.

关键词： strike-slip faulting tectonic style controlling granite emplacement mechanism,Dayishan Hunan Province

Moment tensor analysis of the acoustic emission source in the rock damage process

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第7期15卷 609-613页

作者： YU Huaizhong, ZHU Qingyong, YIN Xiangchu and WANG Yucang ( State Key laboratory of earthquake Dynamics, Institute of Geology, china earthquake Administration, Beijing 100029, china State Key laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of sciences, Beijing 100080, china School of Mathematics and Computational Science, Zhongshan university, Guangzhou 510275, china Center for Analysis and Prediction, china seismological bureau, Beijing 10003., china Quakes, Department of earth Science, university of Queensland, Brishbane, Austrialia) State Key laboratory of earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China. State Key laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China. School of Mathematics and Computational Science Zhongshan University Guangzhou 510275 China. Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China. Quakes Department of Earth Science University of Queensland Brishbane Austrialia

To further investigate the mechanism of acoustic emission (AE) in the rock fracture experiment, moment tensor analysis was carried out. The AE sources characterized by crack sizes, orientations and fracture modes, are represented by a time-dependent moment tensor. Since the waveforms recorded by AE monitors correlate to the moment tensors, we prefer to select the P wave amplitude from the full-space Green's function of homogeneous and isotropic materials to determine the six independent components of the moment tensor. The moment tensor analysis was used to investigate the AE sources recorded in the experiment, and three types of micro-cracks were found, which are tensile mode, shear mode and mixture of the tensile and shear mode. In addition, the motion of micro-cracks was decided by eigenvectors of moment tensor. Results indicate that the moment tensor analysis may be used as a measurement to reflect the damage evolution of rock specimen.

关键词： moment tensor acoustic emission rock fracture.

The history of crustal uplift and metamorphic evolution of Panzhihua-Xichang micro-palaeoland, SW china:Constraints on Sm-Nd, ^(40)Ar/^(3.)Ar and FT ages of granulites

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 {3., Nanjing 210093. china 2. Institute of Geology, china seismological bureau, Beijing 100029, china Department of earth sciences and State Key laboratory for Mineral Deposits Research Nanjing University Nanjing China Institute of Geology China Seismological Bureau 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/3.Ar 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.

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

在线全文

学校读者我要写书评

暂无评论

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 443.03. 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 450053. china 4. Geological Institute, china seismological bureau, Beijing 100029, china 5. Geological Survey Institute of Qinghai Province, Xining 81003., china 6. china university of geosciences, wuhan 43.074, 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±3.)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.