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Preliminary reconstruction of the desert and sandy land distributions in China since the last interglacial period

Science China earth Sciences 2004年第z1期47卷 89-100页

作者： CHEN Huizhong, SU Zhizhu, YANG Ping & DONG Guangrongkey laboratory of Desert and Desertification, Cold and Arid Regions environmental and Engineering Research institute, Chinese Academy of Sciences, Lanzhou 730000, China state key laboratory of loess quaternary geology. institute of earth environment, Chinese Academy of Sciences, Xi’an 710075, China institute of loess Plateau, Shanxi University, Taiyuan 030006, China key laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China state key laboratory of loess quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China institute of loess Plateau Shanxi University Taiyuan China

The desert and sandy land are the products of arid climate. The spatial distribution of modern deserts and sandy land in China and their relation to climate show following characteristics: arid and hyper-arid desert zones, at isohyet of less than 200 mm, are dominated by mobile dunes; semi-arid steppe and arid desert steppe with the precipitation between 200?00 mm, are dominated by semi-fixed and fixed sand dunes; the precipitation of sub-humid forest grassland and humid forest zones with scattered fixed sand land is higher than 400 mm. With this as reference, in combination with considerable amount of paleoclimatic data in desert regions and adjacent regions, the distributions of desert and sandy land in China during the last intergla-cial period, the last glacial maximum (LGM), and the Holocene megathermal, were preliminarily reconstructed. The results compared with that of today show that the distribution of desert and sandy land in China was greatly dwindled during last interglacial period, and the mobile dune area was about two-thirds of that of today's, but greatly expanded during LGM. However, the dwindling area of desert and sandy land in the Holocene megathermal was smaller than that in the last interglacial period. The forcing mechanism was mainly related to the changes of East Asian winter and summer monsoon, south-northward swing of the westerlies and the variations of the Qinghai-Tibet Plateau monsoon intensity caused by global climate changes during the cold and warm intervals since the last interglacial period.

关键词： the glacial-interglacial period, desert, sandy land, spatial distribution.

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New eolian red clay sequence on the western Chinese loess Plateau linked to onset of Asian desertification about 25 Ma ago

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Science China earth Sciences 2011年第1期54卷 136-144页

作者： QIANG XiaoKe AN ZhiSheng SONG YouGui CHANG Hong SUN YouBin LIU WeiGuo AO Hong DONG JiBao FU ChaoFeng WU Feng LU FengYan CAI YanJun ZHOU WeiJian CAO JunJi XU XinWen AI Li state key laboratory of loess and quaternary geology.(SKLLQG) Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China key laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education Chang'an University Xi'an 710065 China

The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.

关键词： Chinese loess Plateau eolian red clay magnetostratigraphy late Oiigocene inland Asia desertification

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Characterization of MASDs of surface soils in north China and its influence on estimating dust emission

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Chinese Science Bulletin 2004年第20期49卷 2169-2176页

作者： MEI Fanmin1,2, ZHANG Xiaoye1, LU Huayu1, SHEN Zhenxing1 & WANG Yaqiang1 1. state key laboratory of loess and quaternary geology. institute of earth environment, Chinese Academy of Sciences, Xian 710075, China 2. Xian University of Engineering Science and Technology, Xian 710048, China state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China Xi''an University of Engineering Science and Technology Xi''an 710048 China

The micro-aggregated size distribution (MASD) of surface soil is an important parameter for modelling dust emission. However, there is no dataset of MASDs of all sur-face soil types in north China. The MASDs are here pre-sented, measured by dry sieving, for typical surface soil sam-ples, including sandy soil, gravelly sand soil, gravelly loam soil, loam soil and silt loam soil, collected from sandy deserts, Gobi deserts, oases, farmlands in steppe regions and steppe areas in north China. The MASDs of various surface soil types exhibit a combination of several log-normal distribu-tions of five separated sizes with mean mass median diame-ters (MMDs) of 90, 210, 390, 600 and 980 mm, respectively, and mean standard deviations (SDs) of 1.25, 1.40, 1.25, 1.35 and 1.25 respectively. The log-normal distributions corre-spond to very fine sand, fine sand, medium sand, coarse sand and very coarse sand population. On the basis of characteri-zation of the retrieved MASDs of various surface soil types in north China, dust emission fluxes are modelled by a dust production model (DPM model). It is shown that dust emis-sion has been significantly influenced by MASDs. Fine sand and very fine sand are always associated with the highest dust emission fluxes. Emission fluxes of the medium sand, gravelly sand soil, gravelly loam soil and loam soil are lower than those of very fine sand and fine sand, but larger than those of the coarse sand. The differences in dust emission fluxes vary among the different soil types from 101 to 103 mg·m-2·s-1. Dust emission fluxes from sandy deserts and farmlands covered with sand sheets in north China rang from 101 to 104 mg·m-2·s-1 while those from Gobi deserts, farmlands and steppes with gravelly desertification range from 101 to 102 mg·m-2· s-1. The modelled results indicate that deserts and farmlands with sand are the major dust sources in north China.

关键词：华北地区 MASDs 微块状粒度分布地面土壤粉尘排放壤土大气污染气溶胶

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Spatial pattern of modern sedimentation rate of Qinghai Lake and a preliminary estimate of the sediment flux

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Chinese Science Bulletin 2010年第7期55卷 621-627页

作者： XU Hai LIU XiaoYan AN ZhiSheng HOU ZhaoHua DONG JiBao LIU Bin state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Shaanxi 710075 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We investigated the spatiotemporal distribution of1 37Cs radioactivity in surface sediment of Qinghai Lake,and developed the spatial pattern of sedimentation ***1 37Cs inventory is higher near the estuary/bank area,but lower at the central *** the other hand,the average1 37Cs activity is lower near the estuary/bank area,but higher at the central *** mass accumulation rate(MAR) and the fluxes and contents of the terrestrial detritus(***2,Fe2O3,and Ti) are higher near the estuary/bank area,but lower at the central *** chemical/biogenic deposits(*** autogenic carbonates) take up higher fractions at the central *** suggest that the spatial pattern of recent sedimentation rate is dominated by the deposition of terrestrial *** average MAR(0.0337 g cm-2a-1) was estimated based on those of different cores of Qinghai Lake and was verified by a Ca mass-balance *** fluxes of total lake sediments,terrestrial detritus,and direct atmospheric deposits were also estimated.

关键词：现代沉积速率沉积物通量空间格局青海湖陆源碎屑沉积 137Cs 估算高等教育

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Effect of precession on the Asian summer monsoon evolution:A systematic review

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Chinese Science Bulletin 2009年第20期54卷 3720-3730页

作者： LIU XiaoDong SHI ZhengGuo state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Geological climatic records and model simulations on the Asian summer monsoon climate change induced by insolation forcing of the earth's precession are systematically reviewed in this *** presentation of the questions on the mechanism of the Asian monsoon evolution at the precession band,currently existing debates and future research directions are *** the early 1980s,more and more observed evidence and simulated results,especially the absolute-dated stalagmite records and orbital-scale transient model runs in the last few years,have indicated that the quasi-20ka period in the quaternary monsoon climate change is caused by ***,debates still exist on the dynamic mechanism how precession affects the Asian *** "zero phase" hypothesis says that the Asian monsoon is merely controlled by summer insolation in the Northern Hemisphere(NH) while the "latent heat" hypothesis emphasizes the dominant effect of latent heat transport from the Southern Hemisphere(SH) besides the role of the northern *** two hypotheses have separately been supported by some *** we are cognizant of the importance of northern solar radiation and the remote effect of southern insolation,it has still a long way to go before comprehensively understanding the evolutionary mechanism of the Asian *** view of the problems existing in present researches of monsoon-dominated climate change at the precession scale,we propose that studies on the environmental significance of geological monsoon proxies,feedback processes in the long-term transient simulations and intercomparisons between observations and modeling results should be strengthened in the future.

关键词：系统评价夏季季风进动效应演变亚洲

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Late Glacial glacier-climate modeling in two valleys on the eastern slope of Samdainkangsang Peak, Nyaiqentanggulha Mountains

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Science China earth Sciences 2017年第1期60卷 135-142页

作者： XU XiangKe DONG GuoCheng PAN BaoLin HU Gang BI WeiLi LIU JinHua YI ChaoLu key laboratory of Tibetan environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100101 China state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi 'an 710061 China College of Resources Environment and Tourism Capital Normal University Beijing 100048 China

Well-preserved Late Glacial moraines in the Barenduo and Yuqiongqu valleys on the eastern slope of the Samdainkangsang Peak present an opportunity to reconstruct glacier extents and examine the character of the climate during the Late Glacial stage in the Nyaiqentanggulha Mountains. This study employs a coupled mass-balance and ice-flow model to reconstruct the glacier extents in the two valleys and assess the magnitudes of temperature and precipitation change during the Late Glacial period. Model results indicate that during the Late Glacial, the Barenduo valley contained an ice volume of 1.67x 108 m3, with the equilibrium-line altitude （ELA） being -5500 m asl; and the Yuqiongqu valley had an ice volume of 5.56x 108 m3, with the ELA being -5470 m asl. A climate scenario, temperature depression of 2.6-2.8°C and 60-70%, percent of modern （1981-2010） precipitation, can sustain both of the Late Glacial glacier extents in the two valleys. A 50% increase or decrease from modern precipitation would have been coupled with the respective Late Glacial temperature depressions of 1.6 and 3.0°C in the Barenduo valley, and 2.1 and 2.8°C in the Yuqiongqu valley.

关键词： Glacier-climate modeling Late Glacial Glacier extent Paleoclimate Samdainkangsang Peak

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A comparative study of n-alkane biomarker and pollen records: an example from southern China

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Chinese Science Bulletin 2009年第6期54卷 1065-1072页

作者： ZHENG YanHong ZHOU WeiJian XIE ShuCheng YU XueFeng state key laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China key laboratory of Biogeology.and environment geology.of Ministry of Education China University of Geosciences Wuhan 430074 China

We report the results of a comparative study of n-alkane biomarkers and pollens in lacustrine and peat deposits at Dingnan, Jiangxi Province in southern China, and discuss the likely causes for the dis-crepancy in the interpretations of the n-alkane biomarker and pollen records in terms of climate and vegetation change. The results show that past changes in climate and vegetation revealed by the n-alkane record are not always consistent with the pollen assemblage record in the whole section. Biomarkers do not permit direct identification of the plant family and/or genus and mainly record compositions of local plant remains, while pollens mainly reflect the regional vegetation change. Bio-markers and pollen records complement each other, providing a better picture of local and regional environments. Furthermore, biomarkers are more sensitive than pollen to climatic and vegetational change. Several climatic events are clearly identified by the n-alkane biomarker proxies, such as C31/(C27+C29+C 31) ratio and can be correlated to the North Atlantic Heinrich event, B/A, YD and two dry-cool events during the early Holocene such as the periods of 9850 to 9585 cal a B.P. and 8590 to 7920 cal a B.P. These events are consistent with those found in the surrounding regions, suggesting that the regional climate was coupled with global-scale abrupt climatic events. Our results suggest that biomarker and pollen data can record the more detailed climate and vegetation information, thus im-proving the resolution and precision of vegetation and climate reconstruction.

关键词：烷烃生物标志物花粉记录华南地区植被变化气候条件个例气候事件孢粉组合

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Simulating the vegetation-producing process in small watersheds in the loess Plateau of China

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Journal of Arid Land 2012年第3期4卷 300-309页

作者： KaiBo WANG ZhouPing SHANGGUAN state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an710075 China Northwest Agriculture and Forestry University Yangling 712100 China

Small watersheds are the basic composition unit of the loess Plateau in China. An accurate estimation of vegetation net primary productivity （NPP） is of great significance for eco-benefit evaluation in small watershed management in this region. Here we describe the development and testing of a vegetation-producing process model （VPP） of a small watershed in the loess Plateau. The model couples three modules： radiation adjustment; soil hydrological processes; and vegetation carbon assimilation. Model validation indicates that the VPP model can be used to estimate the NPP of small watersheds in the region. With the VPP model, we estimated the spatial NPP distributions in the Yangou watershed for 2007. The results show that in the Yangou watershed the NPP is relatively low, averaging 168 g C/（m^2.a）. Trees and shrubs have a higher NPP than crops and grasses. The NPP is larger on the partly shaded and shaded slopes than on the partly sunny and sunny slopes. The NPP on the slopes increases gradually on 0-20° slopes and decreases slightly on slopes steeper than 20°. Our simulation indicates that the vegetation type is the most important factor in determining the NPP distribution in small watersheds in the loess Plateau.

关键词： small watershed net primary productivity vegetation-producing process model solar radiation soil hydrologicalprocess vegetation carbon assimilation

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Identification of Greigite in the Pliocene Sediments of Qinghai Lake and Its Geological Significance

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2261-2262页

作者： FU Chaofeng Jan BLOEMENDAL QIANG Xiaoke Mimi J.HILL AN Zhisheng key laboratory of Western Mineral Resources and Geological Engineering Ministry of Education of ChinaChang'an University state key laboratory of loess and quaternary geology Institute of Earth and EnvironmentCAS Geomagnetism Lab School of Environmental SciencesUniversity of Liverpool

The Qinghai Lake in North China is the largest interior plateau lake in Central Asia, and is sensitive to climate change and the environmental effects of Tibetan Plateau uplift. An almost continuous 626 m long sedimen... 详细信息

关键词： In Lake Identification of Greigite in the Pliocene Sediments of Qinghai Lake and Its Geological Significance

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Soil Carbon, Nitrogen and Microbial Dynamics of Pasturelands: Impacts of Grazing Intensity and Planting Systems

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Pedosphere 2014年第3期24卷 408-416页

作者： WANG Yi DUAN Wen-Xia C.TU S.WASHBURN CHENG Lei S.HU state key laboratory of loess and quaternary geology.institute of earth environment Chinese Academy of Sciences Department of Plant Pathology North Carolina State University Sichuan Tourism University Department of Animal Science North Carolina State University

Management intensity critically influences the productivity and sustainability of pasture systems through modifying soil microbes, and soil carbon （C） and nutrient dynamics; however, such effects are not well understood yet ir the southeastern USA. We examined the effects of grazing intensity and grass planting system on soil C and nitrogen （N） dynamics, and microbial biomass and respiration in a long-term field experiment in Goldsboro, North Carolina, USA. A split-plot experiment was initiated in 2003 on a highly sandy soil under treatments of two grass planting systems （ryegrass rotation with sorghum-sudangrass hybrid and ryegrass seeding into a perennial bermudagrass stand） at low and high grazing densities. After 4 years of continuous treatments, soil total C and N contents across the 0 30 cm soil profile were 24.7% and 17.5% higher at the high than at the low grazing intensity, likely through promoting plant productivity and C allocation belowground as well as fecal and urinary inputs. Grass planting system effects were significant only at the low grazing intensity, with soil C, N, and microbial biomass and respiration in the top 10 cm being higher under the ryegrass/bermudagrass than under the ryegrass/sorghum-sudangrass hybrid planting systems. These results suggest that effective management could mitigate potential adverse effects of high grazing intensities on soil properties and facilitate sustainability of pastureland.

关键词： C allocation grass species microbial respiration microbial biomass pastureland sustainability plant productivity

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