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Paleoenvironments indicated by the fossil mammalian assemblages from red clay-loess sequence in the {2. loess Plateau since 8.0 Ma B.P.

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Science china Earth sciences 2006年第5期49卷 518-530页

作者： XUE xiangxu1,2. ZHAnG Yunxiang1,2.& YUE Leping1,2.1. {3. key {2. of Continent Dynamics (northwest University), Institute of Cenozoic geology and environment, De- partment of geology, northwest University, xi’an 710069, china 2. Institute of Earth environment, {3. key {2. of loess and {12. geology, chinese academy of sciences, xi’an 710075, china 1. state key {2. of Continent Dynamics (northwest University) Institute of Cenozoic Geology and Environment Department of Geology Northwest University Xi’an 710069 China 2. Institute of Earth environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an 710075 China

Information from eleven profiles of eolian earthy red silty clay and loess of the middle of the Late Miocene to Holocene age have been studied and correlated. A complete summary profile with projected isotopic ages and fossil-bearing beds has been assembled. The profile is subdivided into 12.stratigraphic units proceeding from the lower (older) to the upper (younger) one. The character of mammalian assemblages contained in each unit was analyzed and the corresponding pa- leo-climatic environments were deduced. The environmental character of each period and the change from the middle of the Late Miocene at about 8.0 Ma B.P. up to the Holocene progressed from the hot semiarid and semi-moist, warmer-moist, warm-moister of the Late Miocene. To slightly less warm moist, cool-dry, slight-warmer-moister of the Pliocene; later the cool to cold dry periods alternated frequently with the mild semiarid and semi-moist periods of the quaternary. Vegetation progressed from the grasslands with sparse woods, wooded shrub-grasslands and subtropical forest-grasslands of the Late Miocene age to sparse grasslands and dry grasslands of the Pliocene; and to sparse grasslands, dry grasslands and tundras of the quaternary. The climate changes in the neogene were of low-amplitute in a generally warm-humid background. Those of the quaternary were of higher am- plitude with a longer phase. Cool or cold dry and slightly warm semiarid and semi-moist climates al- ternated on a generally cool-dry background. The tendency since the start of the quaternary was the change to more northern and western shift in the loess Plateau, with progressively cooler and dryer conditions. The dramatic uplift of the Qinghai-xizang (Tibet) Plateau and the forming and expansion of the Arctic ice sheet might be the main reasons of the more pronounced changes in the quaternary.

关键词： paleoenvironment, mammalian fossils, eolian red clay-loess sequence, loess Plateau.

The microtine distribution and its environmental significance since the Middle Pleistocene in Zhangping Caves of the Qinling Mountains

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Science china Earth sciences 2008年第2期51卷 294-299页

作者： LI Yongxiang1 & XUE xiangXu1,2.1 state key {2. of Continental Dynamics, Department of geology, northwest University, Institute of Cenozoic geology and environment, xi’an 710069, china 2.Institute of Earth environment, state key {2. of {13. and {12. geology, chinese academy of sciences, xi’an 710075, china 1. state key {2. of Continental Dynamics Department of Geology Northwest University Institute of Cenozoic Geology and Environment Xi’an 710069 China 2. Institute of Earth environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an 710075 China

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to environmental variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493.ka ago, cool and humid at 2.9 ka ago―cold and humid at 2.5 ka ago―cool and humid at 2. ka ago, and warm and dry at present.

关键词： environmental variation since Middle Pleistocene microtine fossils Zhangping Caves of the Qinling Mountains

environmental characteristics of Mid-Holocene recorded by lacustrine sediments from Lake Daihai, north environment sensitive zone,{2.

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Science china Earth sciences 2006年第9期49卷 968-981页

作者： SUn Qianli1,2. ZHOU Jie1, SHEn Ji3. CHEn Peng1,2. WU Feng1,2.& xiE xiuping1,2.1. state key Lab of {2. and quaternary geology, Institute of Earth environment, chinese academy of sciences, xi’an 710075, china 2. Graduate University of chinese academy of sciences, Beijing 10003., china 3. nanjing Institute of Geography and Limnology, chinese academy of sciences, nanjing 2.0008, china 1. state key Lab of {2. and {3. geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 2. Graduate University of chinese academy of sciences Beijing 100039 China 3. nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China

Climate proxies, such as total organic carbon and nitrogen (TOC, Tn), carbonate content (CaCO3., grain-size and pollen of the sediment core retrieved from enclosed Lake Daihai which lies in the north china environment sensitive zone are analyzed to reconstruct the environment evolution of the area based on high-resolution radiocarbon chronology. The results reveal that the TOC and Tn contents of the sediments correlate well with pollen percentage and pollen flux variations during the Holocene, and both reach their peak values simultaneously at 6.7―3.5 ka BP (calendar age, 7.6―3.6 ka BP). Since 6.7 ka BP, both the CaCO3.and organic matter contents of the core have simultaneous variations, and their high values also occur during 6.7―3.5 ka BP. While during 9.0―6.7 ka BP (calendar age, 10―7.6 ka BP) relatively lower level of organic matter content and pollen flux corre- spond to the higher level of carbonate content. The above relations suggest that during 6.7―3.5 ka BP, the productivity and effective precipitation were greatly improved in the lake drainage area, and this would probably strengthen the hydrodynamic conditions, enhancing organic matter, pollen and carbonate inputs from terrestrial sources. Such processes would account for the enrichment of both organic matter and carbonate in the sediments. While during 9.0―6.7 ka BP, the lower level of or- ganic matter, pollen flux but high carbonate content show depressed productivity and declined vege- tation coverage. The higher carbonate content at this stage would have probably resulted from the higher evaporation ratio of the lake water under relatively drier climate conditions. Therefore, it is in- ferred that during 6.7―3.5 ka BP, the climate was more humid with abundant rainfalls and vegetation was more flourishing in the Lake Daihai area. This can be seen as Holocene Climate Optimum (HCO). As a result, this has evident discrepancies with the traditional notion that the HCO occurs at Early Holocene or early Mid

关键词： Lake Daihai, Mid-Holocene, lacustrine sediments, environmental characteristics.

Progress of loess research in china

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Journal of Geographical sciences 2004年第S1期14卷 59-63页

作者： ZHAO Jingbo1,2. HUAnG Chunchang1(1. Department of Geography, Shaanxi normal University, xi'an 710062. china 2. state {2. laboratory of loess and quaternary, Institute of Earth environment, CAS, xi'an 710075, china) Department of Geography Shaanxi Normal UniversityXi'an 710062China state key{2. of {3. and quaternary Institute of Earth EnvironmentCASXi'an 710075China Department of Geography Shaanxi Normal UniversityXi'an 710062China

Progress in chinese loess research made in recent 15 years was introduced in this paper, including mainly distribution and paleo{2. significance of chinese loess, new development of loess formation age, red-brown paleosol types and {2.al change, loess-paleosol sequence and climate cycles, monsoon strength change during last interglacial and last glacial periods in the loess Plateau, climate events, and source areas of loess and material.

关键词： chinese loess paleosols loess age monsoon strength climate events material source

The new basic theory on quaternary environmental research

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Journal of Geographical sciences 2004年第2期14卷 242-250页

作者： ZHAO Jingbo 1, 2. 3.(1. Department of Geography, Shaanxi normal University, xi’an 710062. china 2. Center for Historical environment and Socio-Economic Development in northwest china, Shaanxi normal University, xi’an 710062. china 3. state key laboratory of loess and quaternary, Institute of Earth environment, CAS, xi’an 710075, china) Department of Geography Shaanxi Normal University Xi’an China Center for Historical environment and Socio-Economic Development in northwest china Shaanxi Normal University Xi’an China state key {2. of {3. and quaternary Institute of Earth Environment CAS Xi’an China

On the basis of extensive survey to the quaternary paleosols, soils and weathering layers in the vast northern china and the {2. Plateau, we found some unusually special phenomena of chemical components such as unsuccessive illuvium, twin illuviums, unusually thick illuvium and multi-illuviums etc. According to the analysis on the content of CaCO 3.and the data of penetrating experiment, a new theory of illuvial depth or removal depth of CaCO 3.in weathering and leaching belt was constructed, which indicates that the time of CaCO 3.removing to the illuvial depth is very short, and the effect of time factor on illuvial depth can be ignored. The theory can be taken as a credible foundation for studying many geological and geographical problems in weathering and leaching belt. When the illuvial depth of CaCO 3.is bigger than the thickness of developing belt of soil or paleosol, it can be determined that the paleosol has turned into weathering crust. When the illuvial depth of CaCO 3.is bigger than the thickness of paleosol, paleosol is leaching moderately acid soil. When two, three layers or unusually thick CaCO 3.illuviums exist in the same weathering section or at the bottom of the same paleosol, there were two or more periods forming paleosol and corresponding climatic stages at that time. On the basis of the equation of relationship between mean annual rainfall (y) and illuvial depth of CaCO 3.(x) (y = 3.5.5x + 168.5) determined in the paper, mean annual precipitation during the development of paleosol can be calculated.

关键词： new illuvial theory quaternary soils CaCO_3.remove illuvial types illuvial depth

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

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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 {2. of loess and quaternary geology (SKLLQG),Institute of Earth environment,chinese academy of sciences,xi’an 710075,china 2.Graduate University of chinese academy of sciences,Beijing 100049,china 3.key {2. of Cenozoic geology and environment,Institute of geology and Geophysics,chinese academy of sciences,Beijing 10002.,china state key {2. of {3. and quaternary geology (SKLLQG) Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China Graduate University of chinese academy of sciences Beijing 100049 China key laboratory of Cenozoic {2. and {3. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 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{2. 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

Digital image analysis of palaeoenvironmental records and applications

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chinese Science Bulletin 2002年第23期47卷 1957-1963,2025-2026页

作者： SUn Donghuai1,2. LIU Yu2.& TAn Ming3.. South china Sea Institute of Oceanology, {3.. Guangzhou 5103.1, china 2. state key laboratory of loess and quaternary geology, Earth environmental Institute, {3., xi’an 710075, china 3. Institute of geology and Geophysics, {3., Beijing 10002., china South china Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou China state key {2. of {3. and quaternary geology Earth Environmental Institute Chinese Academy of Sciences Xi’an China Institute of geology and Geophysics Chinese Academy of Sciences Beijing China

environmental change signals in geological or biological records are commonly reflected on their reflecting or transmitting images. These environmental signals can be extracted through digital image analysis. The analysis principle involves section line selection, color value reading and calculating environmental proxy index along the section lines, layer identification, auto-chronology and investigation of structure evolution of growth bands. On detailed illustrations of the image technique, this note provides image analyzing procedures of coral, tree-ring and stalagmite records. The environmental implications of the proxy index from image analysis are accordingly given through application demonstration of the image technique.

关键词： digital image environmental records.