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Application of rock creep experiment in calculating the viscoelastic parameters of earth medium

Science china earth {2. 2006年第5期49卷 492-498页

作者： SHI Xingjue1, WEN Dan1, BAO Xueyang1, LI Chengbo1 & HUANG Yun2.1. School of earth and Space sciences, University of Science and Technology of{2., Hefei 2.002.,{2. 2. Seismological Bureau of Jiangsu Province, Nanjing 2.0014,{2. School of earth and Space sciences University of Science and Technology of China Hefei China Seismological Bureau of Jiangsu Province Nanjing China

Based on the rock creep experiment, the data of aftershock sequence and post-earth- quake deformation are used to estimate the viscosity of crust medium near earthquake focus. Firstly 9 samples that belong to 3 kinds of rock are conducted in creep experiment under constant pressure to obtain the creep curves directly. Inversion results show that the standard linear model is the best one to present the earth medium. It exhibits obvious elasticity within a short time, while it exhibits obvious rheology within a long time. The relationship between element module μ 2.and the whole module μ of standard linear model or the module of real earth medium is calculated and analyzed. On the basis of μ 2.= 2. μ, the sequence of aftershock of Gonghe earthquake in Qinghai Province is analyzed and the relationship between accumulated released strain and the time is obtained, which, combined with the creep experiment results, is used to estimate the viscosity of crustal medium in this area. The measured vertical deformation after the same earthquake also is combined with the creep experiment results, then it is used to calculate the relaxation time and viscosity through three different methods respectively, i.e. inversion of Kelvin model, difference method of deformation and viscoelastic dislo- cation theory. The viscosity of crustal medium in 32.km depth of earthquake focus of Gonghe area deduced from the different data and methods is about 1019 Pa·s, which is the same as the research results by other authors at home and abroad.

关键词： creep experiment, aftershock sequence, post-earthquake deformation, crustal viscosity.

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New technique to control in situ oxygen fugacity in water-free high-pressure system──Using Cu-O as an example

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Chinese Science Bulletin 1998年第16期43卷 1353-1358页

作者： LI Heping 1, XIE Hongsen 1, GUO Jie 1, ZHANG Yueming 1,XU Zuming 1 and XU Ji’an 2.1. Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002. china 2. Institute of {2. sciences, taiwan 1152., china Institute of Geochemistry Chinese Academy of Sciences Guiyang China Institute of earth sciences Taiwan China

Through inserting a solid oxygen-specific electrolyte (YSZ) inside and exerting an electrical power of direct current outside between the sample and oxygen reservoir (an solid oxygen buffer), oxygen was driven by the power from the cathodic electrode area into the positive electrode area at high temperature and high pressure. In this way, the oxygen fugacity in the sample was in situ controlled independently of temperature and pressure. By using Cu-O system as an example, this technique was proved to be successful.

关键词： in situ control of oxygen fugacity water-free system high temperature and high pressure.

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Nonlinear analysis on the coupling process of electromagnetic vibrator and earth

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Science china earth {2. 2005年第8期48卷 1175-1182页

作者： CHEN Zubin1,2. TENG Jiwen2. LIN Jun1, ZHANG Linhang1 & JIANG Zhongjin1 1. Institute of Intelligent Instrument & Measurement Control Technology, Jilin University, Changchun 13002., china 2. Institute of Geology & Geophysics, Chinese Academy of sciences, Beijing 10002., china Institute of Intelligent Instrument & Measurement Control Technology Jilin University Changchun China Institute of Geology & Geophysics Chinese Academy of Sciences Beijing China

The linear model based on the hydraulic pressure vibrator has been no longer adaptable to the electromagnetic vibrator. In order to realize the effective transmission of the limited energy from the vibrator to the ground, it is important to study the coupling model of the electromagnetic vibrator and the earth. In this paper, a nonlinear restore term was introduced to the coupling model because of the existence of a large amount of harmonics in the vibrator baseplate. The nonlinear vibration analysis was applied to the model by the multiscale method. In the course of energy transmission from the vibrator to the ground, ultraharmonic resonance was used to explain the generation of harmonics. An improved scheme was advanced to select the cross correlation reference signal in the vibrator seismic exploration. Good application results were obtained in field experiments.

关键词： vibrator, coupling model, electromagnetic, nonlinear vibration.

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Science china earth {2. 2004年第10期47卷 896-911页

作者： ZHANG Changhou1,2. WU Ganguo1,2. WANG Genhou2. ZHANG Weijie2.& SONG Honglin2.1. Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology, china University of Geosciences, Ministry of Education of china, Beijing 100083, china 2. School of earth sciences and Mineral Resources, china University of Geosciences, Beijing 100083, china Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology China University of Geosciences Ministry of Education of China Beijing China School of earth sciences and Mineral Resources China University of Geosciences Beijing China

The northwest trending tectonic belt in the middle part of the Mesozoic intraplate Yanshan Orogenic Belt, northeast Hebei Province, is composed of thrusts, extensional faults, strike-slip faults and syntectonic sedimentations as well. The northeastward basement-involved major thrusting deformation occurred between 174Ma and 168MaBP and was followed by an intrusion of the granitic plutonic rocks. As a part of the post-thrusting extensional deformations a northwest extending volcano-sedimentation system of Late Jurassic and Early Cretaceous formed in the southwest side of the belt. These volcano-sedimentary sequences are divided into Tuchengzi Formation, Zhangjiakou Formation, Yixian Formation and Jiufotang Formation re- spectively. They are characterized by southeastward migration as a result of the increasing down-dip slip displacement along the major extensional fault toward the southeast of the belt. The provenance area of the Jiufotang Formation north to it experienced southwestward thrusting during and after its later sedimentation. The thrusting in this stage resulted in the formation of an asymmetric footwall syncline with vergence to SW in the Jiufotang Formation in the NE side of the basin. Finally a dextral strike-slip deformation occurred along the NW tectonic belt. The striking tectono-geomorphological features and present seismic activities along this belt indicate that it has been being active since Cenozoic era and is still in the active state at present. This northwest extending tectonic belt was following the same direction and location as the existing fault systems within the basement as revealed by former geological and geophysical studies. So it is reasonable to infer the Mesozoic deformation along this belt to be a result of reactivation of the basement structures in a favorable tectonic stress field. The reactivation of basement struc- tures might be taken as one of the mechanisms of intraplate deformation and orogeny.

关键词： Yanshan Orogenic Belt, northwest extending tectonic complex, thrust system, geochronology.

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Origin of the Red earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science china earth {2. 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2. JI Junfeg3, WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of earth Environment, Chinese Academy of sciences, Xi’an 710075,{2. 2. Department of Urban and Resources sciences, Nanjing University, Nanjing 2.0093,{2. 3. Department of earth sciences, Nanjing University, Nanjing 2.0093,{2. 4. Department of Geography, Shaanxi Normal University, Xi’an 710062.{2. 5. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 10002.,{2. 6 Department of Geography, Qinghai Normal University, Xining 810008,{2. 7. Graduate School of the Chinese Academy of sciences, Beijing 100039,{2. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate School of the Chinese Academy of sciences Beijing China Department of Urban and Resources sciences Nanjing University Nanjing China Department of earth sciences Nanjing University Nanjing China Department of Geography Shaanxi Normal University Xi’an China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Department of Geography Qinghai Normal University Xining China

The Red earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red earth sequenceconsists of 2. visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red earth *** REE distributions of the loess-soil and the Red earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the Redearth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

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A circum-earth shear zone at low-latitudes and episodic large earthquakes in it and the circum-Pacific seismic zone

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Science china earth {2. 2006年第9期49卷 897-903页

作者： MA Zongjin1, DU Pinren1, REN Jinwei2.& GAO Xianglin1 1. Institute of Geology, china earthquake Administration, Beijing 10002., china 2. Institute of earthquake Science, china earthquake Administration, Beijing 100036, china Institute of Geology China Earthquake Administration Beijing China Institute of earthquake Science China Earthquake Administration Beijing China

Because of the differential motions between the Northern and Southern Hemispheres of the earth, there exists a motion discordant zone between them. On the surface this zone consists of 13 large faults dominant with strike-slip. We call it a global shear zone at low-latitudes (E system). By statistical analysis of temporal distribution of earthquakes Mw≥7.5 in the E system and the circum-Pacific (P system) during 1900―2.03, we find that there exist quasi-episodic and alternative activities in and between these two systems. This phenomenon is likely associated with the half-sphere oscillation in dilation and contraction and the change of the earth’s rotation rate.

关键词： shear zone, circum-Pacific zone, great earthquake, quasi-episode.

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“Double dawn”eclipse and the rotational variation of the earth

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Chinese Science Bulletin 2000年第11期45卷 988-991页

作者： ZHANG Peiyu & HAN Yanben1. Purple Mountain Observatory, Chinese Academy of sciences, Nanjing 2.0008, china 2. Beijing Astronomical Observatory, Chinese Academy of sciences, Beijing 100012. National Astronomical Observatory, Chinese Academy of sciences, Beijing 100012. china Purple Mountain Observatory Chinese Academy of Sciences Nanjing China Beijing Astronomical Observatory Chinese Academy of Sciences Beijing National Astronomical Observatory Chinese Academy of Sciences Beijing China

A record of 'double dawn' at State Zheng in the first year of the reign of King Yi in Western Zhou Dynasty in the chronicle 'Bamboo Annals' (Zhushu Jinian) is discussed. We think that it may be a record of an annular solar eclipse happening in 899 BC. The record and the AT, which describes the secular variation of the earth’s rotation, are analyzed and discussed.

关键词： solar eclipse earth’s rotation.

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Magnetic properties of Jiaxian red clay sequences from northern Chinese Loess Plateau and its paleoclimatic significance

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Science china earth {2. 2005年第8期48卷 1234-1245页

作者： QIANG Xiaoke, AN Zhisheng, LI Huamei, CHANG Hong & SONG Yougui 1. SKLLQG, Institute of earth Environment, Chinese Academy of sciences, Xi’an 710075,{2. 2. Guangzhou Institute of Geochemistry, Chinese Academy of sciences, Guangzhou 510640,{2. Chinese Academy of sciences SKLLQG Institute of Earth Environment Xi’an China Chinese Academy of sciences Guangzhou Institute of Geochemistry Guangzhou China

Detailed rock magnetism investigation of the Jiaxian red clay sequences indicated that there are common magnetic mineralogy properties in red clay and loess-paleosol sequences from the Chinese Loess Plateau as well as the marked properties of themselves, magnetic min-erals mainly with magnetite, maghemite, hematite, and possibly limonite/goethite contributing to the magnetic behavior. Meanwhile, it is found that the strong paleosol in red clay sequences has a lower coercivity and higher content of ultra-fine ferrimagnetic grains than that of the weak pa-leosol, which is similar to loess and paleosol in upper Wucheng Loess sequences, and indicates that humid conditions and relatively strong pedogenesis play a significant role in the increase of ultra-fine magnetic minerals and transformation of the magnetic minerals. This suggests that, like Quaternary loess-paleosols, the change of characteristics of paleoclimatic conditions of the late Tertiary red clay deposits is fluctuant. In addition, the results of magnetic hysteresis properties show that the applied saturated field for samples from the Jiaxian red clay sequences is higher than that of the samples from eastern and southern Chinese Loess Plateau. It is obviously shown that there exist more hard magnetic minerals and relatively weak biochemical processes in the Jiaxian red clay sequences on northern Chinese Loess Plateau. We conclude that the paleocli-matic environment is different between northern and eastern/southern Chinese Loess Plateau, and it should be more arid in northern Chinese Loess Plateau.

关键词： northern Chinese Loess Plateau, red clay, magnetic property, paleoclimatic significance.

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Paleoceanographic evolution recorded in the northern South china Sea since 4 Ma

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Science china earth {2. 2005年第12期48卷 2166-2173页

作者： HUANG Baoqi1,2. JIAN Zhimin2.& WANG Pinxian2.1. School of earth and Space sciences, Peking University, Beijing 100871,{2. 2. Laboratory of Marine Geology, Tongji University, Shanghai 2.0092.{2. School of earth and Space sciences Peking University Beijing China Laboratory of Marine Geology Tongji University Shanghai China

Upper water structure over the last 4 million years in the northern South china Sea (SCS) was reconstructed by sea surface temperature (SST) and primary productivity estimated by changes in the abundance of planktonic foraminifer, planktonic foraminifer transfer function, and the accumulation rate of benthic foraminifera. Results of SST and primary productivity show that SST gradually decreased since 4 Ma, but differential seasonal temperature and primary productivity increased in steps mainly at about 3.1, 2.7, 2.1, 1.6, 0.9 and 0.5 Ma. Comparison with tectonics and orbital variations indicates that phased rising of the Tibet since 3.6 Ma, closing of Panama and Indonesian seaways, and orbital changes were responsible for the changes of upper water structure in the SCS, respectively.

关键词： northern South china Sea, upper water structure, Late Pliocene, planktonic foraminifer, ODP 1146.

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Characteristics of rare earth elements in soils in Guizhou carbonate region

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Chinese Science Bulletin 1999年第S2期44卷 115-116页

作者： YAN Chongling~(1,2., HONG Yetang~1, WANG Shijie~1, FU Shunzhen~2. ZHU Keyong~2.and WU Shanqi~2.1. State Key Laboratory of Environmental Geochemistry, Chinese Academy of sciences, Guiyang 550002. china 2. Guizhou Institute of Environmental Protection, Guiyang 550002. china State Key Laboratory of Environmental Geochemistry Chinese Academy of Sciences Guiyang 550002 China Guizhou Institute of Environmental Protection Guiyang 550002 China

IN recent years, rare earth element (REE) being used in agriculture has gained greater progress and madeus reach some common views. The centent of REE (especially soluble REE) in soils has significantcorrelation with that of REE plant absorbed from soil. Therefore, it is very necessary to clarify contentvariation and background values of REE (especially soluble REE ) from the angles of relation of supplyand demand between soil and plants, for reasonably using REE and formulating relevant health standardin the region, avoiding excessive using REE and taking up soil environmental capacity of REE to result insoil or water-body polluted and sometime for researching rock weathering, soil-forming process and soilclassification in the region. This note deals with characteristics of content and distribution of REE andsoluble REE in soils of Guizhou carbonate region.

关键词： rare earth element soil, Carbonate area, Guizhou.

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