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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 sciences 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,{3. 2. Department of Urban and Resources sciences, Nanjing University, Nanjing 210093.{3. 3. Department of Earth sciences, Nanjing University, Nanjing 210093.{3. 4. Department of Geography, Shaanxi Normal University, Xi’an 710062,{3. 5. institute of geology and geophysics, Chinese academy of sciences, beijing 100029,{3. 6 Department of Geography, Qinghai Normal University, Xining 810008,{3. 7. Graduate School of the Chinese academy of sciences, beijing 10003.,{3. 1. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 7. Graduate School of the Chinese academy of sciences Beijing 100039 China 2. Department of Urban and Resources sciences Nanjing University Nanjing 210093 China 3. Department of Earth sciences Nanjing University Nanjing 210093 China 4. Department of Geography Shaanxi Normal University Xi’an 710062 China 5. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China 6. Department of Geography Qinghai Normal University Xining 810008 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 25 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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δ^13.sc values of the loess-paleosol sequence in Dali area, Shaanxi Province, china, and paleoenvironmental implications

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Chinese Science Bulletin 2003年第9期48卷 902-907页

作者： LI Yumei & LIU Dongsheng (LIU Tungsheng)institute of geology and geophysics, Chinese {3. of sciences, beijing 100029 (e-mail: liyrney@***) 1. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029

The carbon isotopic ratios of carbonate in the two profiles of the Dali area were analyzed and some new understandings on the influencing factors of the δ13.SC value of the loess-paleosol sequence and its paleoenvironmental implications were discussed preliminarily in this report. The 13.SC value of the Dali loess-paleosol sequence is synchronizing with the variance of magnetic susceptibility basically and the negative peaks of the δ13.SC curves are corresponding to the different developmental periods of the paleosol. It is believed that the intervention of the CO2 produced by plants will cause the decrease of the δ13.SC value, the amplitude of which may be relevant to the paleovegetation density and the ancient humidity. The relative biomass of C4 plants in the vegetation will affect the sublevel change of the δ13.SC. Low δ13.SC value by and large indicates the environmental conditions of the relatively abundant vegetation and humid climate. During the last 250000 years, the period with the sparsest vegetation and the most arid climate is the phase of the loess in L2 depositing and the period with the most abundant vegetation and the most humid climate is the last interglacial period. The δ13.SC curves of Dali also show that the High Temperature and Large Precipitation Event of the Qinghai-Tibetan Plateau during 40-3. kaBP had affected the Central Shaanxi Plain with relatively humid climate, and had apparent influence on the local vegetation and humidity.

关键词：古环境大理地区黄土陕西湿润气候碳同位素植被高温天气

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TAKE ANOTHER VISION TO THE UPLIFT OF THE QING—ZANG (TIBETAN) PLATEAU BASED ON CENOZOIC VOLCANISM

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地学前缘 2000年第S1期7卷 370-371页

作者： Liu Jiaqi [WT5,5”BX](institute of geology and geophysics,Chinese {3. of sciences,beijing 100029, china)

The emergence of the Qing—Zang plateau is among the most important geological events on the globe since the Cenozoic Era. Many geological issues can find answer from here. The major issues concerning plateau probably have three: (1) geodynamics, timing and speed of the plateau uplift;(2) The plateau uplift impact on surrounding environment;(3. mineral resources in the plateau. The authors want to focuses on first issue based on volcanisms occurred in interior and surrounding of the plateau, The new opinions are following:(1) Each volcanic eruptive episode corresponded to strong uplift stage;(2) The dynamic mechanism of the plateau uplift can not ignore another force from west beyond collision between Indian and Eurasia plates from South;(3. The surrounding volcanic chain is not only related to the collision from South, but also from west.

关键词： Tibetan plateau the Cenozoic volcanism volcanic chain surro unding plateau west collision uplift mechanism

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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 510640,{3. 2. Wuhan University, Wuhan 43.072,{3. 3. institute of geology,{3. Seismological Bureau, beijing 100029,{3. 4. Faculty of Earth sciences,{3. University of Geosciences, Wuhan 43.074,{3. 1. Guangzhou institute of Geochemistry Chinese Academy of Sciences 510640 Guangzhou China 2. Wuhan University 430072 Wuhan China 3. institute of geology China Seismological Bureau 100029 Beijing China 4. Faculty of Earth sciences China University of Geosciences 430074 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.

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The species diversity of fusulinaceans and high-frequency sea-level changes in the Carboniferous-Permian boundary section at Xikou, Zhen'an County,Shaanxi Province, china

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Science china Earth sciences 2006年第7期49卷 673-683页

作者： ZHANG Haijun1, WANG Xunlian2, DING Lin1, XIA Guoying3.& WANG Lei2 1. institute of Tibetan Plateau Research, Chinese academy of sciences, {3. 100085, china 2. Faculty of Earth sciences and Mineral Resources, china University of Geosciences, {3. 100083. china 3. Tianjin institute of geology and Mineral Resources, Tianjin 3.0170, china 1. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Faculty of Earth sciences and Mineral Resources China University of Geosciences Beijing 100083 China 3. Tianjin institute of geology and Mineral Resources Tianjin 300170 China

The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history. In this paper, the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou, Zhen’an County, Shaanxi Province, is analyzed quantitatively, and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed. As a whole, the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou, Zhen’an County, from the Late Carboniferous to the Early Permian. There is a significant increase in species diversity around the Carboniferous-Permian boundary, which is one of the biggest bio-events of the fusulinacean fauna, and represents the radiation of Pseudoschwagerininae subfamily in the studied area. Integrated fusulinacean species diversity into sequence stratigraphic framework, de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location, and is essentially controlled by the sea-level changes, especially by the high-frequency sea-level changes. Generally, the species diversity of fusulinaceans is low, and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level; whereas the species diversity of fusulinaceans is high, and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level. Within the third-order depositional sequence, the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low, and it increases upward. The fusulinacean species diversity is low within the transgressive syst

关键词： fusulinaceans, species diversity, high-frequency cyclothem, sequence stratigraphy, sea-level changes, Carboniferous-Permian boundary, Zhen'an, Shaanxi.

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Geological analysis and physical modeling of structural pumping in high effective formation of Kela 2 gas field

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Science china Earth sciences 2006年第10期49卷 1070-1078页

作者： ZHAO Wenzhi1, WANG Hongjun1, SHAN Jiazeng2, WANG Zecheng1 & XU Dafeng1 1. Research institute of Petroleum Exploration and Development, Petrochina, beijing 100083.{3. 2. institute of geology and geophysics, Chinese academy of sciences, beijing 100029,{3. 1. Research institute of Petroleum Exploration and Development Petrochina Beijing 100083 China 2. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China

In a 3.D closed geological body, in case “structural expanding” inside is induced by stress, it can produce the pressure difference between the expanding cell and surrounding rock, then generate a pumping force directed toward the cell and accelerate the directional flow of fluid in the strata. The structural style and conditions of gas reservoir-formation in the Kuqa depression are favorable to the structural pumping. According to similarity principle, a physical modeling of structure formation and gas filling process of the Kela 2 gas field has justified the occurrence of structural pumping and its important role in gas-reservoir formation with high efficiency under the compressive and well-sealed circumstance. Therefore, authors propose that structural pumping is an important mechanism of gas reservoir-formation with high efficiency in the Kuqa depression.

关键词： Kela 2 gas field, structural pumping, gas-reservoir formation mechanism, high efficiency,physical modeling.

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Progress and review of the studies on the end-Triassic mass extinction event

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Science china Earth sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2, LU Yuanzheng1,2,3.& XU Daoyi4 1. Research institute of Petroleum Exploration and Development, beijing 100083. china 2. Key Laboratory of Oil and Gas Reservoir of Petro{3., beijing 100083. china 3. china University of Geosciences, beijing 100083. china 4. institute of geology, china Earthquake Administration,{13., china 1. Research institute of Petroleum Exploration and Development 100083 Beijing China 2. Key Laboratory of Oil and Gas Reservoir of Petrochina 100083 Beijing China 3. china University of Geosciences 100083 Beijing China 4. institute of geology China Earthquake Administration 100029 Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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Plumb line variation at Tangshan during 1987―1998 and its relation with the earthquakes around

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Science china Earth sciences 2009年第1期52卷 101-107页

作者： LI ZhengXin1,2 & LI Hui3.1 Shanghai Observatory,Chinese academy of sciences,Shanghai 20003.,china 2 {3. of Geodesy and geophysics,Chinese academy of sciences,Wuchang 43.077,china 3.{3. of Seismology,china Earthquake Administration,Wuchang 43.071,china Shanghai Observatory Chinese Academy of Sciences Shanghai 200030 China institute of Geodesy and geophysics Chinese Academy of Sciences Wuchang 430077 China institute of Seismology China Earthquake Administration Wuchang 430071 Chin

Plumb line variations(PLV) at Tangshan during the years of 1987―1998 are determined by using the 46 batch repeated gravity observations of the beijing-Tangshan *** has been found that PLV at Tangshan are related with the 3. earthquakes in this *** appears that the time of an earthquake around Tangshan is usually quite the same when PLV at Tangshan begins moving in opposite direction.

关键词： plumb line variations network in northern china variations of local gravity field earthquakes

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Carbon and Oxygen Stable Isotope Values and Microfossils at 41.4-4.5ka BP in Tai Co,Tibet,china,and Their Paleoclimatic Significance

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1036-1050+1052-1056+1051页

作者： ZHENG Mianping~(1,2,*),LIU Junying~(1,3.,MA Zhibang~(1,4),WANG Hailei~(1,2) and MA Nina~(1,2) 1 MLR Key Laboratory of Saline Lake Resources and Environment,institute of Mineral Resources,CAGS, beijing 10003.,china 2 Research and Development Center for Saline Lakes and Epithermal Deposits,Chinese {3. of Geological sciences,beijing 10003.,china 3.institute of geology,Chinese {3. of Geological sciences,beijing 10003.,china 4 Key Laboratory of Cenozoic geology and Environment,Chinese {3. of sciences,beijing 100029, china MLR Key Laboratory of Saline Lake Resources and Environment Institute of Mineral Resources CAGS Beijing 100037 China Research and Development Center for Saline Lakes and Epithermal Deposits Chinese Academy of Geological Sciences Beijing 100037 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China Key Laboratory of Cenozoic geology and Environment Chinese Academy of Sciences Beijing 100029 China *Correspondence: Mianping ZHENG *Correspondence: Corresponding author. E-mail: zhengmp2010@***

Two sedimentary sections were measured at Tai Co(Co means lake in Tibetan) in western Tibet,*** two sections are almost all composed of clay carbonate beds except in their lower parts where there are carbonized plants at>10 cm depths and dark-colored carbonate clay and clay at 50-70 cm depths,yielding abundant gastropods,ostracods,and *** carbon and oxygen stable isotope values of carbonate,ostracods,and charophytes and ecological features of microfossil communities indicate the following climatic change in the area from 41.4 to 4.5 ka BP:at 41.4-26.2 ka BP,the climate was relatively wet;at 26.2-25.5 ka BP,it was slightly warm-dry;at 25.5-22.5 ka BP,it was warm-wet;at 22.5-21.0 ka BP,it was slightly cold-wet;at 20.5-17.5 ka BP,it became cold abruptly and slightly wet,implying the climate of the last glacial maximum;at 17.5-16.0 ka BP,it was slightly cold-dry;at 16.0-11.8 ka BP,it was slightly warm-wet;at 11.8-10.4 ka BP,it was relatively cold-dry, roughly equivalent to the climate of the Younger Dryas,and at 10.4 ka BP,the temperatures began to rise again;at 10.4-9.4 ka BP,it was slightly warm-wet;at 9.4-8.5 ka BP,there occurred short warm-wet oscillations;at 8.5-7.9 ka BP,it was slightly dry-cold,representing a strong temperature-lowering and drying event in the postglacial stage;at 7.8-6.3.ka BP,it was slightly warm-wet;at 6.3.4.5 ka BP,the climate tended to be cold-dry.4.5 ka BP recorded the maximum aridity since the late part of the late Pleistocene.

关键词： sedimentary environment index paleoclimatic changes late Pleistocene-Holocene(41.4-4.5 ka BP) Tai Co Tibet

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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 geophysics,Chinese {3. of sciences beijing 100029,Chinese institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China

Molecular dynamics simulations are performed to observe the evolutions of 512 and 51262 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 23. 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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