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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 sciences 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 51064.,{2. 1. chinese academy of sciences SKLLQG Institute of Earth Environment 710075 Xi’an China 2. chinese academy of sciences Guangzhou Institute of Geochemistry 510640 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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^(14.C measurement of forest soils in Dinghushan Biosphere Reserve

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chinese Science Bulletin 1999年第3期44卷 251-256页

作者： SHEN Chengde , LIU Dongsheng (LIU Tungsheng) , PENG Shaolin, SUN Yanmin , JIANG Mantao , Yl Weixi , XING Changping , GAO Quanzhou , LI Zhi’an and ZHOU Guoyi Guangzhou institute of Geochemisry, chinese academy of sciences, Guangzhou 51064.,{2. institute of {4., chinese academy of sciences , Beijing 100029,{2. South{2. institute of Botany, chinese academy of sciences, Guangzhou 510650,{2. Guannzhou institute of Geochemisry Chinese Academy of Sciences Guanazhou China institute of geology Chinese Academy of Sciences Beijing China South china institute of Botany Chinese Academy of Sciences Guangzhou China

Organic carbon in forest soils of Qingyunsi and Wukesong profiles can be divided into fast and slow components. Δ14. values of these profiles decrease with increasing of depth. The Δ14. values in 30—4. cm depth int... 详细信息

Organic carbon in forest soils of Qingyunsi and Wukesong profiles can be divided into fast and slow components. Δ14./sup>C values of these profiles decrease with increasing of depth. The Δ14./sup>C values in 30—4. cm depth interval of Wukesong profile are decreasing sharply until a very low value,showing that a strong geological environment change occurred about 1 560 years ago. The 14./sup>C apparent ages of Wukesong profile show that the coniferous and broad-leaf mixed forests around Wukesong profile have been developing since 4.0} a BP, which is consistent with historical documents. The penetrating depths of "bomb 14./sup>C" in Qingyunsi and Wukesong profiles are 10 and 2. cm, respectively.

关键词： Dinghushan forest soil 14. tracing 14. apparent age.

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Oxygen isotope compositions of eclogites in Rongcheng,Eastern china

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chinese Science Bulletin 2003年第4期48卷 372-378页

作者： CHU Xuelei1,2. GUO Jinghui1,2. FAN Hongrui1,2.& JIN Chengwei1 1. institute of {4. and {2., chinese academy of sciences, Beijing 100029, china 2. Key Laboratory for Mineral Resources Research, chinese academy of sciences, Beijing 100101, china Correspondence should be addressed to Chu Xuelei institute of geology and {2. Chinese Academy of Sciences Beijing 100029 China Key Laboratory for Mineral Resources Research Chinese Academy of Sciences Beijing 100101 China

Collected from the Rongcheng region, Shan-dong Province, the three types of eclogites suffering the UHP (i.e. ultra-high pressure) metamorphism have obviously dif-ferent oxygen isotope compositions. The eclogites occurring in regional orthogneisses and ultramafic rocks have the oxy-gen isotope compositions of normal eclogites in the world,but the eclogites existing in marbles are extremely enrichedin 18O. By applying oxygen isotope geothermometry, for theall types of eclogites, the temperature estimates of quartz-garnet pair, in principle, indicate the formation temperatures of eclogites, so that the peak-metamorphic temperatures are estimated to be averagely little higher than 800℃, which are consistent with the estimates by using other geothermome-ters according to cation partitioning between coexistingphases. The d 18O values of eclogitic inclusions hosted inmarbles from Yangguantun, Rongcheng region, are farhigher than the values of eclogites (including eclogitic inclu-sions in marbles) from the Dabieshan and other places of the Sulu. The oxygen isotope compositions of various mineralsindicate that the formation temperatures of eclogites fromthe Rongcheng region, in general, are higher than that from the Dabieshan and the southwestern part of the Sulu, but the dispersive temperatures estimated by different mineral pairs probably reflect that the UHP eclogites from the Rongcheng region generally suffered overprinted metamorphisms dur-ing the exhumation.

关键词：苏鲁超高压变质带 UHP 山东荣成榴辉岩氧同位素成分

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Jinning granodiorite and diorite deeply concealed in the central Tarim Basin

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Science china Earth sciences 2005年第12期48卷 2061-2068页

作者： LI Yuejun1, 2. SONG Wenjie2. WU Genyao1, WANG Yifen1, LI Yuping2.& ZHENG Duoming2.1. {4. of geology & {2., chinese academy of sciences, Beijing 100029, china 2. Tarim Oil-field Company, Petrochina, Korla 84.000, china 1. institute of geology & {2. Chinese Academy of Sciences 100029 Beijing China 2. Tarim Oil-field Company 841000 Korla PetroChina China

The 72.0-m-deep Well Tacan 1 in the central Tarim Basin is the deepest in china. Purplish gray medium-grained granodiorite containing dark gray fine-grained diorite xenolith is revealed at the base of the well (7169―72.0 m), and they are results of the Jinning magmatic activities. Trace-element geochemistry and REE profiles of both rock types are similar, indicating that they are calc-alkaline series I-type granitoid. Proxies of diorite signify the development of a magmatic arc due to subduction at ca. 12.0 Ma. The granodiorite was formed before 890―932.Ma. However, more study is needed to clarify if the arc diorite represents a ca. 300 Ma extension of the subduction or a reactivation during the orogenic collision event at ca. 900 Ma.

关键词： diorite, granodiorite, magmatic arc, Jinning orogeny, Tarim Basin.

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TIME-IGGCAS model validation:Comparisons with empirical models and observations

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Science china Technological sciences 2008年第3期51卷 308-322页

作者： YUE XinAn1,2.3, WAN WeiXing1, LIU LiBo1, NING BaiQi1, ZHAO BiQiang1 & ZHANG ManLian1 1 institute of geology and {2.,{4., Beijing 100029, china 2.Wuhan institute of Physics and Mathematics,{4., Wuhan 4.0071, china 3 Graduate University,{4., Beijing 10004., china 1. institute of geology and {2. Chinese Academy of Sciences Beijing 100029 China 2. Wuhan institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China 3. chinese academy of sciences Graduate University Beijing 100049 China

The TIME-IGGCAS (Theoretical Ionospheric Model of the Earth in institute of Ge- ology and geophysics,{2.) has been developed re- cently on the basis of previous works. To test its validity, we have made compari- sons of model results with other typical empirical ionospheric models (IRI, NeQuick-ITUR, and TItheridge temperature models) and multi-observations (GPS, Ionosondes, Topex, DMSP, FORMOSAT, and CHAMP) in this paper. Several conclu- sions are obtained from our comparisons. The modeled electron density and elec- tron and ion temperatures are quantitatively in good agreement with those of em- pirical models and observations. TIME-IGGCAS can model the electron density variations versus several factors such as local time, latitude, and season very well and can reproduce most anomalistic features of ionosphere including equatorial anomaly, winter anomaly, and semiannual anomaly. These results imply a good base for the development of ionospheric data assimilation model in the future. TIME-IGGCAS underestimates electron temperature and overestimates ion tem- perature in comparison with either empirical models or observations. The model results have relatively large deviations near sunrise time and sunset time and at the low altitudes. These results give us a reference to improve the model and enhance its performance in the future.

关键词： ionosphere theoretical model empirical model satellite observation relative deviation

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MOLECULAR DYNAMICS SIMULATIONS OF FILLED AND EMPTY CAGE-LIKE WATER CLUSTERS IN LIQUID WATER AND THEIR SIGNIFICANCE TO GAS HYDRATE FORMATION MECHANISMS

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化工学报 2003年第Z1期54卷 62-66页

作者： GUO Guangjun,ZHANG Yigang and ZHAO Yajuan institute of geology and {2.,chinese {4. of sciences Beijing 100029,chinese institute of geology and {2. Chinese Academy of Sciences Beijing 100029 China

Molecular dynamics simulations are performed to observe the evolutions of 512.and 512.2.cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 2.0 K and 2.0 K. The lifetimes of these clusters are calculated according to their Lindemann index δ (t) using the criteria of δ≥0.07. For both the filled and empty clusters, we find the dynamics of bulk water determines the lifetimes of cage-like water clusters, and that the lifetime of 512.62.cage-like cluster is the same as that of 512.cage-like cluster. Although the methane molecule indeed makes the filled cage-like cluster more stable than the empty one, the empty cage-like cluster still has chance to be long-lived compared with the filled clusters. These observations support the labile cluster hypothesis on the formation mechanisms of gas hydrates.

关键词： like in time that were MOLECULAR DYNAMICS SIMULATIONS OF FILLED AND EMPTY CAGE-LIKE WATER CLUSTERS IN LIQUID WATER AND THEIR SIGNIFICANCE TO GAS HYDRATE FORMATION MECHANISMS of cage GAS

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Genesis of excess argon in phengite and significance of ^(4.)Ar-^(39)Ar age spectra for omphacite:A case study on UHP eclogite of South Dabie Terrain,china

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chinese Science Bulletin 2000年第15期45卷 1345-1351页

作者： WANG Songshan, GE Ningjie, SANG Haiqing & QIU Ji1. institute of geology and {2., chinese academy of sciences, Beijing {4., china 2. Department of Earth and Space Science, University of Science and Technology of china, Hefei 2.002., china Correspondence should be addressed to Wang Songshan institute of geology and {2. Chinese Academy of Sciences Beijing China Department of Earth and Space Science University of Science and Technology of China Hefei China

The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4.1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.

关键词： South Dabie Terrain ultrahigh-pressure metamorphics phengite omphacite excess argon.

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Mineralization episode of porphyry copper deposits in the Jinshajiang-Red River mineralization belt: Re-Os dating

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Science china Earth sciences 2005年第2期48卷 192-198页

作者： WANG Denghong, QU Wenjun, LI Zhiwei, YIN Hanlong4.& CHEN Yuchuan institute of Mineral Resources, chinese {2. of Geological sciences, Beijing 100037,{4. National Center of Rock and Mineral Analysis, chinese {2. of Geological sciences, Beijing 100037,{4. Resource Assessment Center of Yunnan, Kunming 650011,{4. institute of geology and {12., chinese academy of sciences, Beijing 100101,{4. chinese {2. of Geological sciences, Beijing 100037,{4. 1. institute of Mineral Resources Chinese Academy of Geological Sciences 100037 Beijing China 2. National Center of Rock and Mineral Analysis Chinese Academy of Geological Sciences 100037 Beijing China 3. Resource Assessment Center of Yunnan 650011 Kunming China 4. institute of geology and {2. Chinese Academy of Sciences 100101 Beijing China 5. chinese academy of Geological {2. 100037 Beijing China

Re-Os isotopic dating for the molybdenites from the porphyry copper deposits of the Jinshajiang-Red River mineralization belt in Yunnan Province yields isochron ages of 33.9±1.1 Ma for the Machangqing deposit and 34.4.0.5 Ma for the Tongchang deposit. This result shows that both the Machangqing and the Tongchang porphyry Cu-Mo deposits from two different ore-fields formed simultaneously. This new data and the published Re-Os model ages of molybdenite (35.4.Ma, 35.9 Ma, 36.2.Ma) of the Yulong porphyry copper deposit in Tibet, which is located in the same Jinshajiang-Red River mineralization belt as the Machangqing deposit and the Tongchang deposit, suggest that these three Cenozoic porphyry copper deposits in the Jinshajiang-Red River mineralization belt were contemporary for their mineralization episode. That is to say, even their present locality is far away and nearly iso-distantly distributed, these three porphyry Cu(Mo) deposits belong to the same mineralization episode at the end of Eocene.

关键词： Re-Os isotopic dating, porphyry Cu deposits, Cenozoic, mineralization episode.

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Garnet Sm-Nd and U-Pb systems: A case study of a granulite from the European Variscan belt

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chinese Science Bulletin 2002年第15期47卷 1284-1288页

作者： CHEN FukunInstitut fur Mineralogie, Petrologie und Geochemie, Universitat Tubingen, 72.74.Tubingen, Germany institute of geology and {2.,{4., Beijing 100029, china Institut für Mineralogie Petrologie und Geochemie Universität Tübingen Tübingen Germany institute of geology and {2. Chinese Academy of Sciences Beijing China

This study presents zircon and garnet ages of a mafic granulite from the high-grade Variscan basement of the Black Forest, Germany and discuss isotope closure temperature of garnet Sm-Nd and U-Pb systems. Zircon grains yield 2.7Pb/2.6Pb ages between -34. and -4.4.Ma by the U-Pb and evaporation methods. In contract, garnet dating gives Sm-Nd and Pb-Pb isochron ages of (398±3) Ma and (4.1±14. Ma, respectively, which are older than most of zircon ages. These data imply that most of zircons lost radiogenic Pb, probably due to metamictization or recrystallisa-tion during the granulite-facies metamorphism (-800°C) at -34. Ma. Garnet Sm-Nd and U-Pb systems preserve chronological information of pro-grade metamorphism, probably profiting from a fluid-absence metamorphic environment. These results demonstrate that garnet mineral can be a better candidate than zircon mineral to date high-grade metamorphism by the U-Pb and Sm-Nd methods in some cases.

关键词： Variscan granulite garnet Sm-Nd U-Pb.

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Modeling the impact of Australian Plate drift on Southern Hemisphere climate and environment

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chinese Science Bulletin 2005年第14期50卷 1495-1502页

作者： ZHOU Botao1,5, ZHAO Ping2. JIAN Zhimin3 & HE Jinhai4.1. Nansen-Zhu International Research Center, institute of Atmospheric Physics, chinese academy of sciences, Beijing {2.,{4. 2. institute of Climate and Environment, chinese academy of Meteoro- logical sciences, Beijing 100081,{4. 3. Laboratory of Marine geology, Tongji University, Shanghai 2.0092.{4. 4. Department of Atmospheric sciences, Nanjing institute of Meteorol- ogy, Nanjing 2.004.,{4. 5. Graduate School of the chinese academy of sciences, Beijing 100039,{4. Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of the chinese academy of sciences Beijing 100039 China institute of Climate and Environment Chinese Academy of Meteorological Sciences Beijing 100081 China Laboratory of Marine geology Tongji University Shanghai 200092 China Department of Atmospheric sciences Nanjing Institute of Meteorology Nanjing 210044 China

Using a global atmosphere-ocean coupled model with the present-day and 14.MaB.P. oceanic topogra- phy respectively, two experiments are implemented to inves- tigate the effect of different locations of Australian Plate on the atmospheric circulation in middle-high latitudes of the Southern Hemisphere. The results show that when Austra- lian Plate lay south at 14.MaB.P., both anticyclone circula- tions in the subtropical oceans and cyclone circulation around 60°-70°S are strengthened. Subtropical highs and circumpolar low pressure appear stronger, which results in much stronger Antarctic Oscillation and shorter period of Antarctic Oscillation Index (AOI) at 14.MaB.P. The rainfall and the surface air temperature also change correspondingly. The precipitation decreases around 4.°S and increases around 60°-70°S, and the surface air temperature rises in high latitudes of the South Pacific and descends over the Weddell Sea and its north side. Besides, due to the changes of the temperatures and winds, Antarctic sea ice coverage also changes with its increasing in the Ross Sea and its west re- gions and decreasing in the Weddell Sea.

关键词：半球气候地球环球澳大利亚漂流物海洋地形学

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