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Neogene eolian deposits within the West Qinling Mountains:Climatic and tectonic implications

chinese Science Bulletin 2010年第15期55卷 1483-1487页

作者： ge junyi 1,2.& guo zhengtang 3 1 state key laboratory of loess and quaternary geology (SKLLQG),{2. of Earth environment,chinese academy of sciences,xi’an 710075,china 2.Graduate University of chinese academy of sciences,Beijing 100049,china 3 key laboratory of Cenozoic geology and environment,{2. of geology and geophysics,chinese academy of sciences,Beijing 10002.,china state key {2. of loess and quaternary geology (SKLLQG) Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of chinese academy of sciences Beijing China key laboratory of Cenozoic {2. and environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

The Qinling Mountains constitute a key climate barrier between southern and northern *** recent investigations revealed widely spread eolian deposits of Neogene age mantling the piedmont highlands of the intermountain basins within West ***-mammalian fossils dated a 150.2.m section (NL-VI) near xihe for the late Miocene to Pliocene (～10-4 Ma).Soil micromorphology,grain-size and geochemical analysis consistently define typical loess-soil alternations for the upper (0-66 m) and lower (98-150.2.m) parts of the section,with the middle section (66-98 m) having been affected by episodic slope *** results add important insights to the earlier studies about the widespread eolian deposition in northern china during the Miocene,prior to 8 *** also suggest that the basic configuration of the ridges and inter-ridge basins of West Qinling has already formed by ～10 *** well-preserved eolian deposits are unlikely to support intense substratum deformation and rapid uplift of West Qinling since the late Miocene.

关键词：秦岭山脉风尘堆积构造意义气候新近纪晚中新世地球化学分析风尘沉积

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Changes in the content of eolian iron during the past 900 ka and the implications

Changes in the content of eolian iron during the past 900 ka...

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中国科学院地质与地球物理研究所2.03学术年会

作者： WEI Jianjing~1 & guo zhengtang~(2.1) 1.{2. of geology and geophysics,chinese academy of sciences, Beijing 10002.,china 2.state key laboratory of loess and quaternary geology.{2. of Earth environment.chinese academy of sciences.xi’an 710075. china

In this study,total FeO content(Fe,) in two parallel sections from the central loess Plateau(xifeng and Changwu) is analyzed to address the variations of eolian iron in the past 900 *** obtained timeseries indicate that Fet values in some glacial intervals are comparable to that of interglacial periods and its oscillations do not generally correspond to the long-term glacial-interglacial ***, it exhibits higher frequency fluctuations without detectable 100 ka period,but with a strong 2. ka period and a clear 40 ka *** combination of 2. ka and 40 ka periods suggest that eolian iron content was relatively independent of glacial-interglacial changes,but more strongly influenced by the insolation changes in the northern *** iron content was observed for the S5-1 soil that is correlative to marineδO stage *** marine records,this stage is characterized by higherδC values,suggesting that the event is of global significance.

关键词： loess-paleosol sequences eolian iron paleoclimate spectral analysis

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Impact of Topography and Land-Sea Distribution on East Asian Paleoenvironmental Patterns

Impact of Topography and Land-Sea Distribution on East Asian...

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中国科学院地质与地球物理研究所2.06学术年会

作者： ZHANG Zhongshi~(1,2.,WANG Huijun~2.guo zhengtang~(3,1),and JIANG Dabang~2.1 {2. of geology and geophysics,chinese academy of sciences,Beijing 10002. 2.Nansen-Zhu International Research Center,{2. of Atmospheric Physics, chinese academy of sciences,Beijing 10002. 3 state key laboratory of loess and {12. geology,{2. of Earth environment, chinese academy of sciences,xi’an 710075

Much geological research has illustrated the transition of paleoenvironmental patterns during the Cenozoic from a planetary-wind-dominant type to a monsoon-dominant type, indicating the initiation of the East Asian monsoon and inland-type ***,there is a dispute about the causes and mechanisms of the transition,especially about the impact of the Himalayan/Tibetan Plateau uplift and the Paratethys Sea *** numerical sensitivity experiments under dirent land-sea distributions and Himalayan/Tibetan Plateau topography conditions are performed here to simulate the evolution of climate belts with emphasis on changes in the rain band,and these are compared with the changes in the paleoenvironmental patterns during the Cenozoic recovered by geological *** consistency between simulations and the geological evidence indicates that both the Tibetan Plateau uplift and the Paratethys Sea retreat play important roles in the formation of the monsoon-dominant environmental pattern. Furthermore,the simulations show the monsoon-dominant environmental pattern comes into being when the Himalayan/Tibetan Plateau reaches 1000-2.00 m high and the Paratethys Sea retreats to the Turan Plate.

关键词： Paratethys Sea retreat Himalayan/Tibetan Plateau uplift paleoenvironmental pattern precipitation field Turan Plate

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Land use induced changes of organic carbon storage in soils of {2.

Land use induced changes of organic carbon storage in soils ...

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中国科学院地质与地球物理研究所2.03学术年会

作者： HAIBIN WU~*,zhengtang guo~(1+*) and CHANGHUI PENG~(++) *{2. of Earth environment,1state key laboratory of loess and quaternary geology,chinese academy of sciences,xi’an 710075,{12.,+{2. of geology and geophysics,chinese academy of sciences,PO Box 982.,Beijing 10002.,{12.,++{2. of Atmospheric sciences,South Dakota School of Mines and Technology 501 E.St Joseph,Rapid City,SD 57701-3995,USA

Using the data compiled from china’s second national soil survey and an improved method of soil carbon bulk density,we have estimated the changes of soil organic carbon due to land use,and compared the spatial distribution and storage of soil organic carbon (SOC) in cultivated soils and noncultivated soils in *** results reveal that～57% of the cultivated soil subgroups(～31%of the total soil surface) have experienced a significant carbon loss,ranging from 40%to 10%relative to their noncultivated counterparts. The most significant carbon loss is observed for the non-irrigated soils(dry farmland) within a semiarid/semihumid belt from northeastern to southwestern china, with the maximum loss occurring in northeast *** the contrary,SOC has increased in the paddy and irrigated soils in northwest *** significant change is observed for forest soils in southern china,grassland and desert soils in northwest china,as well as irrigated soils in eastern *** SOC storage and density under noncultivated conditions in china are estimated to～77.4Pg(10g) and～8.8 kg Cm,respectively, compared to a SOC storage of～70.3 Pg and an average SOC density of～8.0 kg Cm under the present-day *** suggests a loss of～7.1 Pg SOC and a decrease of -0.8 kg Cm SOC density due to increasing human activities,in which the loss in organic horizons has contributed to～77%.This total loss of SOC in china induced by land use represents～9.5%of the world’s SOC *** amount is equivalent to～3.5 ppmv of the atmospheric CO ***～78%of the currently cultivated soils in china have been degraded to a low/medium productivities and are responsible for most of the SOC loss,an improved land management,such as the development of irrigated and paddy land uses,would have a considerable potential in restoring the SOC *** a restoration of～50%of the lost SOC during the next 2.-50 years,the soils in china would absorb～3.5 Pg of carbon from the atmosphere.

关键词： carbon density carbon pool human activities soil organic carbon loss

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