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Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central Chinese loess Plateau

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Chinese Science Bulletin 2007年第17期52卷 2407-2412页

作者： DU XueQing1,6, WANG YongHong2, REN JianGuo3, YE xianRen4 & LU HuaYu5,1 1 state key laboratory of loess and quaternary geology, institute of earth environment, Chinese Academy of Sciences, xi’an 710075, china 2 College of Marine Geosciences, Ocean University of china, Qingdao 266003, china 3 National Natural Science Foundation of china, Beijing 100085, china 4 Lanzhou Research Center for Petroleum and Natural Gas Resources, institute of geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, china 5 key laboratory of Coast and Island Development, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093, china 6 Graduate University of Chinese Academy of Sciences, Beijing 100049, china state key laboratory of loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of Chinese Academy of Sciences Beijing China College of Marine Geosciences Ocean University of China Qingdao China National Natural Science Foundation of china Beijing China Lanzhou Research Center for Petroleum and Natural Gas Resources Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou China key laboratory of Coast and Island Development School of Geographic and Oceanographic Sciences Nanjing University Nanjing China

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planet... 详细信息

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the earth surface sediments. Since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concen- tration and helium isotopic ratio. Results show that the 3He/4He ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4He ratio of the extracted magnetic substances is also higher than that of the average level of the earth’s crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

关键词：中国黄土高原古土壤氦同位素行星际尘埃颗粒反方向磁化

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高地降温效应与构造-气候旋回

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山地学报 2007年第4期25卷 400-405页

作者：张信宝贺秀斌汪阳春中国科学院水利部成都山地灾害与环境研究所中国科学院水利部成都山地灾害与环境研究所四川成都610041 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室陕西西安710075 中国科学学院研究生院北京100049

基于辐射平衡的原理,提出'高地降温效应'假说,阐明高原隆升与全球气候变冷的机制。地球如同被玻璃(大气层)包裹的、接受太阳辐射的球体,这层玻璃易于太阳短波的透入,不易于地面长波的散出,起到了很好的保温作用。玻璃越厚,保温效果越好... 详细信息

基于辐射平衡的原理,提出'高地降温效应'假说,阐明高原隆升与全球气候变冷的机制。地球如同被玻璃(大气层)包裹的、接受太阳辐射的球体,这层玻璃易于太阳短波的透入,不易于地面长波的散出,起到了很好的保温作用。玻璃越厚,保温效果越好,地球表面的热能量水平越高,地面温度也越高;反之,地面温度越低。估算了青藏高原和同纬度长江中下游平原之间的逆辐射量差值,用以表征高原隆升的逆辐射量减少值,进而又估算了全球高原隆升的逆辐射量减少值及占地球接受太阳辐射总量的比例。'高地降温效应'假说可以较好的解释寒武纪以来三次重大的构造运动-地貌演化-气候变化过程。构造运动形成高大山系和高原,引起全球降温,气候变冷;随着隆升的山系和高地逐渐被侵蚀为低地,地球表面变得平坦,全球大气层的温室效应增强,全球复又升温,气候变暖。青藏高原的形成,如同地球开了一个散热的'天窗',对新生代以来全球的持续降温作出了重要的贡献。

关键词：高地降温效应地球构造地貌气候

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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2003学术年会

作者： WEI Jianjing~1 & GUO Zhengtang~(2,1) 1.institute of geology and Geophysics,Chinese Academy of Sciences, Beijing 100029,china 2.state key laboratory of loess and quaternary geology.institute 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 20 ka period and a clear 40 ka *** combination of 20 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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Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions

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Science china earth Sciences 2006年第2期49卷 193-201页

作者： LEI Tingwu1,2, LIU Han1, PAN Yinghua3, ZHAO Jun2, ZHAO Shiwei2 & YANG Yonghui2 1. The key laboratory of Modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineer-ing, china Agricultural University, Beijing 100083, china 2. state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau, institute of Soil and Water Conservation, Yangling 712100, china 3. Geographic and Resources Management College, Yantai Normal University, Yantai 264025, china The key laboratory of Modern Precision Agriculture System Integration Research College of Hydraulic and Civil Engineering China Agricultural University Beijing China state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau Institute of Soil and Water Conservation Yangling China Geographic and Resources Management College Yantai Normal University Yantai China

The soil infiltrability of hill-slope is important to such studies andpractices as hydrological process, crop water supply, irrigation practices, and soil erosion. A newmethod for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-outwas advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimatedfrom the advances of runoff on soil surface and the water running out of the slope were *** of 2 cases were conducted. case Ⅰ was done under a rainfall intensity of 20 mm/h, at aslope gradient of about 0° with a runoff/on length (area) ratio of 1 : 1. case Ⅱ was under arainfall intensity of 60 mm/h and a slope of 20° with a runoff/on length (area) ratio of 1 : *** ring method was also used to measure the infiltrability for comparison purposes. Theexperiments were done with soil moisture of 10%. Required data were collected from laboratoryexperiments. The infiltrability curves were computed from the experimental data. The resultsindicate that the method can well conceptually represent the transient infiltrability process, withcapability to simulate the very high initial soil infiltrability. The rationalities of the methodand the models were validated. The errors of the method for the two cases were 1.82%/1.39% and4.49%/3.529% (Experimental/Model) respectively, as estimated by comparing the rainfall amount withthe infiltrated volume, to demonstrate the accuracy of the method. The transient and steadyinfiltrability measured with double ring was much lower than those with this new method, due towater supply limit and soil aggregates breaking down at initial infiltration stage. The method canovercome the short backs of the traditional sprinkler method and double ring method for soilinfil-traility. It can be used to measure the infiltrability of sloped surface underrainfall-runoff-erosion conditions, in the related studies.

关键词： Infiltrability, runoff-on-out, rainfall, sloped surface, model.

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Micro-particle deposition and lobar distribution of mass flow in human upper respiratory tract model

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Science Bulletin 2011年第Z1期 380-385页

作者： HUANG JianHua1 & ZHANG LianZhong1,2 1 School of Physics,Nankai University,Tianjin 300071,china 2.state key laboratory of loess and quaternary geology.institute of earth environment,Chinese Academy of Sciences,xi’an 710075.china

A representative human upper respiratory tract model consisting of oropharyngeal and asymmetric tracheobronchial(TB) airways from the trachea(G0) to the main lobar bronchi(G2) was constructed. Laminar-to-turbulent airflow for typical inhalation modes as well as micro-particle transportation,wall deposition and mass flow to lobes was simulated using the CFX10.0 software from Ansys Inc. The numerical particle deposition efficiency of the oropharynx region and two generations(G1 and G2) of TB airways shows great agreement with the experimental data obtained from realistic casts. The particle deposition pattern indicates that inertial impaction is the primary mechanism in the human upper airway,and turbulence dispersion performs crescent influence especially for small particles. The initial positions of particles with different fates are confined to specifically concentrated zones. The particle mass distributions of five lobes are close to airflow distributions. The upper lobes receive fewer particles than lower lobes and the right middle lobe receives the least.

关键词： upper respiratory tract asymmetric tracheobronchial airways transportation and deposition lobar differences computational fluid dynamics simulation

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Using soil surface gray level to determine surface soil water content

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Science china earth Sciences 2010年第10期53卷 1527-1532页

作者： ZHU YuanJun1,2,WANG YunQiang1,2 & SHAO MingAn1,2 1 state key laboratory of Soil Erosion and Dryland Farming on loess Plateau,institute of Soil and Water Conservation,Northwest A & F University,Yangling 712100,china 2 institute of Soil and Water Conservation,Chinese Academy of Sciences & Ministry of Water Resources,Yangling 712100,china state key laboratory of Soil Erosion and Dryland Farming on loess Plateau Institute of Soil and Water Conservation Northwest A & F University Yangling China institute of Soil and Water Conservation Chinese Academy of Sciences & Ministry of Water Resources Yangling China

How to determine surface soil water content(SWC) quickly and accurately is fundamental in studying eco-hydrological processes and their *** we use laboratory experiments to determine surface SWC using soil surface gray level(SGL) values.A negatively exponential relationship exists between SGL and SWC,i.e.,SGL increases with the decrease of *** can be estimated based on initial SGL value(surface gray level when SWC=0),SWC,and a surface roughness coefficient characterized by mean soil particle *** variation range of SGL was larger than that of SWC,indicating that changes in SWC were enhanced in SGL,and that SGL would thus be sensitive to changes in soil *** the 95% confidence level,SWC can be determined by using the relationship between SWC and SGL established by the *** determination of SWC has a high precision when SWC was between dry and saturated.

关键词： loess Plateau soil water remote sensing surface roughness

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Physical mechanisms of plant roots affecting weathering and leaching of loess soil

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Science china earth Sciences 2006年第9期49卷 1002-1008页

作者： LI Yong1,2, ZHANG Qingwen1,2, WAN Guojiang3, HUANG Ronggui3, PIAO Hechun3, BAI Lingyu2 & LI Lu2 1. state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau, institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100, china 2. institute of Agro-environment and Sustainable Development, Chinese Academy of Agricultural Sciences, Beijing 100081, china 3. institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling China institute of Agro-environment and Sustainable Development Chinese Academy of Agricultural Sciences Beijing China institute of Geochemistry Chinese Academy of Sciences Guiyang China

Plant roots have potential impacts on soil mineral weathering and *** objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the Chinese loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 24.2% of the soil *** roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement > increase of bio-active substance > stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.

关键词： plant roots, soil weathering and leaching rates, soil environment field, principal components analysis (PCA), Chinese loess Plateau.

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重庆武隆喀斯特旅游资源开发与生态环境保护对策

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中国人口·资源与环境 2012年第S1期22卷 172-175页

作者：郑国璋山西师范大学城市与环境科学学院山西临汾041004 重庆师范大学地理与旅游学院重庆400047 中国科学院地球环境科学研究所黄土与第四纪地质国家重点实验室陕西西安710075

本文通过分析重庆武隆喀斯特旅游资源开发利用现状及其存在的生态环境问题,提出了武隆喀斯特旅游景区生态环境保护的对策:树立保护优先、开发为辅的意识,积极开展生态旅游;建立健全地质灾害监测预警机制,维护旅游安全和旅游形象;建立健... 详细信息

本文通过分析重庆武隆喀斯特旅游资源开发利用现状及其存在的生态环境问题,提出了武隆喀斯特旅游景区生态环境保护的对策:树立保护优先、开发为辅的意识,积极开展生态旅游;建立健全地质灾害监测预警机制,维护旅游安全和旅游形象;建立健全喀斯特环境监测预警系统,为景区环境安全提供信息支撑;建立健全退耕还林政策的长效机制,保护景区生态环境;加大旅游科研投入,提高旅游文化品位。

关键词：武隆喀斯特旅游资源生态环境重庆

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environmental archaeology of the Dachang region in the Daning Valley,the Three Gorges reservoir region of the Yangtze River,china

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Chinese Science Bulletin 2008年第S1期53卷 140-152页

作者： ZHANG Yun 1 &ZHU Cheng 2 1 state key laboratory of Vegetation and environmental Change,institute of Botany,Chinese Academy of Sciences,Beijing 100093, china 2 School of Geographic and Oceanographic Sciences,Nanjing University,Nanjing 210093,china state key laboratory of Vegetation and environmental Change Institute of Botany Chinese Academy of Sciences Beijing China School of Geographic and Oceanographic Sciences Nanjing University Nanjing China

environmental archaeology of archaeological sites on both sides of the Dachang section in the Daning River,the Three Gorges of the Yangtze River,shows that riverbed evolution has a great influence on the distribution of archaeological sites during the prehistorical and historical period,and it restricts human activity and the development of ancient *** investigation,dating data,paleocurrent analysis of 100 gravels on the riverbed and archaeological excavation reveal that the riverbed of the Dachang section developed in the Shuangyantang region during the early stage,after about 30 kaBP it shifted westward gradually and reached the present *** with the westward shift,the focus of ancient culture changed for several *** the Western Zhou Dynasty's period,the east riverbank of the Daning River was the main residential *** the Han Dynasty,along with the westward shift,the living space of ancient people was no longer confined to the east riverbank and the focus of culture moved *** the Zhangjiawan site became the main dwelling *** the late Han Dynasty, the villages were flooded and the ancients had to immigrate to a high *** of the Han and the Jin Dynasties outcropped on the flood plain of the east bank because their surface sediments were eroded by several flood events and the westward shift of the riverbed.

关键词： the Daning River environmental archaeology the Shuangyantang site the Zhangjiawan site tombs of the Han and the Jin Dynasties

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Mineral-magnetic signal of long-term climatic variation in Pleistocene fluvio-lacustrine sediments,Nihewan Basin(North china)

Mineral-magnetic signal of long-term climatic variation in P...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Hong Ao Paleomagnetism and Geochronology laboratory(SKL-LE),institute of geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,china key laboratory of loess and quaternary geology.institute of earth environment,Chinese Academy of Sciences,xian 710075.china Graduate University of Chinese Academy of Sciences,Beijing 100049,china

The Nihewan Basin(around 40°N,North china)is a major focus of investigations into hominid occupation in the eastern Asia during the early Pleistocene,thus the paleoenvironmental evolution in this area is crucial for understanding of early human habitation at high northern latitudes of East *** retrieve reliable long-term paleoenvironmental signals from the Nihewan fluvio-lacustrine sequences,I conduct an environmental magnetic investigation on the Pleistocene xiantai fluvio-lacustrine sequence at the eastern margin of the Nihewan *** suggest that there exist an up-section decreasing trend in magnetic mineral concentration and grain size,which is attributed to a long-term decrease in abundance of magnetic minerals in the catchments and in transportation of detrital magnetic minerals into the Nihewan paleolake.I further reveal that these long-timescale variations are related to a long-term decrease in East Asian monsoon precipitation and humidity in the Nihewan Basin during the *** paleoclimate inference is consistent with the increasing aridification in Asian mainland during the Pleistocene, an important climate response to increasing global ice volume.

关键词： environmental magnetism Mineral magnetism Nihewan Basin Pleistocene Fluvio-lacustrine sediment

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