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基于知识的空间图像专题分析与制图 被引量:4
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作者 傅肃性 傅俏燕 《地理学报》 EI CSCD 北大核心 2001年第B09期98-102,共5页
重点论述了遥感专题制图信息源的地学分析,从不同的层面、不同角度,运用相应的技术方法进行探讨,包括空间图像信息的地学特性和时间特性的研究。如不同地区的作物(水稻、玉米和小麦等)的物候期(分蘖、拔节和抽穗等);以及基于专家知... 重点论述了遥感专题制图信息源的地学分析,从不同的层面、不同角度,运用相应的技术方法进行探讨,包括空间图像信息的地学特性和时间特性的研究。如不同地区的作物(水稻、玉米和小麦等)的物候期(分蘖、拔节和抽穗等);以及基于专家知识的图像空间信息分析与制图和地球信息融合体系在遥感制图中的应用与发展。将专业知识(专家知识等)运用于空间图像的分析、处理与制图是地学信息图谱研究的重要组成内容与途径。 展开更多
关键词 遥感专题制图 信息融合体系 空间图像信息 地学特性 时间特性
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Biogeochemical characteristics of nitrogen and phosphorus in Jiaozhou Bay sediments 被引量:6
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作者 李学刚 宋金明 +2 位作者 袁华茂 戴纪翠 李宁 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2007年第2期157-165,共9页
Sediment samples were cored from 3 locations representing the inner bay, the outer bay and the bay mouth of Jiaozhou Bay in September 2003 to study the source and biogeochemical characteristics of nitrogen and phospho... Sediment samples were cored from 3 locations representing the inner bay, the outer bay and the bay mouth of Jiaozhou Bay in September 2003 to study the source and biogeochemical characteristics of nitrogen and phosphorus in the bay. The content and vertical distributions of total nitrogen (TN), total phosphorus (TP), organic nitrogen (ON), organic phosphorus (OP), inorganic nitrogen (IN), inorganic phosphorus (IP), the ratio of organic carbon and total nitrogen (OC/TN), and the ratio of total nitrogen and total phosphorus (TN/TP) in the sediments were analyzed. The results show that both TN and TP in surface sediments decrease from the inner bay to the outer bay. In general, ON occupies 50%?70% of TN and IP accounts for more than 60% of TP. In ratio of OC:TN, the nitrogen accumulated in the sediments from the inner bay and the bay mouth came mainly from terrestrial sources, and the portion of autogenetic nitrogen was 28.9% and 13.1%, respectively. However, in the outer bay, nitrogen was mainly autogenetic, accounting for 62.1% of TN, whereas phosphorus was mainly land-derived. The sedimentation fluxes of nitrogen and phosphorus varied spatially. The overall diagenesis rate of nitrogen was higher than that of phosphorus. Specifically, the diagenesis rate of OP was higher than that of IP. However, the diagenesis rate of ON was not always higher than that of IN. In species, the diagenesis rate of IN is sometimes much higher than that of the OC. In various environments, the diagenesis rate is, to some degree, affected by OC, pH, Eh, and Es. 展开更多
关键词 NITROGEN PHOSPHORUS biogeochemical characteristics SEDIMENT Jiaozhou Bay
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Geochemistry and Zircon U–Pb age of the Yao'an pseudoleucite porphyry,Yunnan Province,China 被引量:10
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作者 Chundi Sun Peng Wu +4 位作者 Die Wang Shenjin Guan Xiaojun Jiang Longyan Jiang Longyan Wang 《Acta Geochimica》 EI CAS CSCD 2017年第2期316-328,共13页
The Yao'an Pb–Ag deposit, located in the Chuxiong Basin, western Yangtze Block, is an important component of the Jinshajiang–Ailaoshan alkaline porphyry–related polymetallic intrusive belt. This complex suite o... The Yao'an Pb–Ag deposit, located in the Chuxiong Basin, western Yangtze Block, is an important component of the Jinshajiang–Ailaoshan alkaline porphyry–related polymetallic intrusive belt. This complex suite of rock bodies includes a vein of pseudoleucite porphyry within deposits of syenite porphyry and trachyte.The pseudoleucite is characterized by a variable greyish,greyish-white, and greyish-green porphyritic texture. Phenocrysts are mainly pseudoleucite with small amounts of alkali feldspar and biotite. In an intense event, leucite phenocrysts altered to orthoclase, kaolinite, and quartz.Both the pseudoleucite porphyry and the syenite porphyry samples were typical alkali-rich, K-rich, al-rich rocks with high LaN/YbNratios; enriched in light rare earth elements and large-ion lithophile elements, and depleted in high field strength elements; and with strongly negative Ta, Nb, and Ti(TNT) anomalies and slightly negative Eu anomalies—all characteristics of subduction-zone mantle-derived rock.We obtained a LA-ICP-MS zircon U–Pb age of 34.1 ± 0.3 Ma(MSWD = 2.4), which is younger than the established age of the Indian and Eurasian Plate collision.The magma derived from a Type-II enriched mantle formed in a post-collisional plate tectonic setting. The geochemical characteristics of the Yao'an pseudoleucite porphyry are powerful evidence that the porphyry'sdevelopment was closely linked to the Jinshajiang–Ailaoshan fault and to the Indian-Eurasian collision. 展开更多
关键词 GEOCHEMISTRY U-Pb age Pseudoleucite porphyry Pb-Ag deposit Yao'an Yunnan Province
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Estimation of aerosol properties over the Chinese desert region with MODIS AOD assimilation in a global model
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作者 YIN Xiao-Mei DAI Tie +4 位作者 XIN Jin-Yuan GONG Dao-Yi YANG Jing TERUYUKI Nakajima SHI Guang-Yu 《Advances in Climate Change Research》 SCIE CSCD 2016年第1期90-98,共9页
A Local Ensemble Transform Kalman Filter assimilation system has been implemented into an aerosol-coupled global nonhydrostatic model to simulate the aerosol mass concentration and aerosol optical properties of 3 dese... A Local Ensemble Transform Kalman Filter assimilation system has been implemented into an aerosol-coupled global nonhydrostatic model to simulate the aerosol mass concentration and aerosol optical properties of 3 desert sites(Ansai, Fukang, Shapotou) in northwestern China. One-month experiment results of April 2006 reveal that the data assimilation can correct the much overestimated aerosol surface mass concentration, and has a strong positive effect on the aerosol optical depth(AOD) simulation, improving agreement with observations. Improvement is limited with the?ngstr€om Exponent(AE) simulation, except for much improved correlation coefficient and model skill scores over the Ansai site. Better agreement of the AOD spatial distribution with the independent observations of Terra(Deep Blue) and Multi-angle Imaging Spectroradiometer(MISR) AODs is obtained by assimilating the Moderate Resolution Imaging Spectroradiometer(MODIS) AOD product, especially for regions with AODs lower than 0.30. This study confirms the usefulness of the remote sensing observations for the improvement of global aerosol modeling. 展开更多
关键词 Aerosol properties Aerosol assimilation Moderate Resolution Imaging Spectroradiometer Multi-angle Imaging Spectroradiometer PM10
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Biological Characteristics of Carex brunnescens for Sand Fixation in the Source Region of the Yellow River 被引量:1
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作者 康建军 赵明 +3 位作者 马和 张洋东 刘冬皓 童胜利 《Agricultural Science & Technology》 CAS 2017年第9期1716-1722,1725,共8页
Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River (Maqu), plays an important role in maintaining the ecosystem stability of alpine grassland in Maq... Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River (Maqu), plays an important role in maintaining the ecosystem stability of alpine grassland in Maqu. In this study, the biological characteristics (phonological characters, the growth process of overground and underground organs, and the morphological characters of underground organs) of C. brunnescens were studied by a field observation experiment. The results showed that C. brunnescens had the characteristics of turning green earlier than other plants, a long growth period, and two flowering and fruiting cycles. The leaf width, length and number of a single plant, and the density, coverage and leaf density of community increased significantly from the leaf extension period to the fruit mature period and then tended to be stable in the withering period, while the plant height and leaf area of a single plant and the leaf area of community rose significantly at first and then decreased. Underground stems (horizontal and vertical stems) and roots of C. brunnescens could survive in sand at a depth of 0-60 cm. The number of middle roots (0.2-0.5 mm in diameter) was the largest in all soil layers (0-20, 20-40 and 40-60 cm), and the total length of fine roots (〈0.2 mm) were the maximum in the sand at a depth of 20-40 cm, while the total length of middle roots was the maximum in the sand layer at a depth of 0-20 cm. The length, fresh weight and dry weight of the main root, horizontal and vertical stems was the maximum in the sand layer at a depth of 10-30 cm and was the minimum in the sand layer at a depth of 40-50 cm. It is concluded that C. brunnescens can well adapt to the alpine sand habitat of Maqu, can be used as the constructive species for ecological restoration in the alpine desertified grassland of Maqu, and has good popularization and application prospects. 展开更多
关键词 Source region of Yellow River (Maqu) Desertified grassland Carex brunnescens Biological characteristics for sand fixation
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Observations of Aerosol Optical Properties in the Beijing Urban Area in Summer 被引量:6
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作者 JING Jun-Shan ZHANG Ren-Jian +1 位作者 TAO Jun ZHANG Lei-Ming 《Atmospheric and Oceanic Science Letters》 2011年第6期338-343,共6页
To investigate aerosol optical properties in the Beijing metropolitan area, aerosol absorption coefficient (Ab), scattering coefficient (So), and fine particulate matter (PM2.5) were measured in the Beijing urba... To investigate aerosol optical properties in the Beijing metropolitan area, aerosol absorption coefficient (Ab), scattering coefficient (So), and fine particulate matter (PM2.5) were measured in the Beijing urban area from 20 May to 30 August 2009. The average Ab, So, single scat- tering albedo (SSA), and PM2.5 concentration were 58.0±39.5 M m^-1, 343.5±353.7 M m 1, 0.80±0.10 and 63.6+50.0 μg m^-3, respectively, during the observation period. Ab, Sc, and SSA all showed single peak diurnal variations, with their maximum values being measured at 0500, 1000, and 1300 local time, respectively. Ab and Sc had a strong positive correlation with PM2.5, and Ab, Sc, and PM25 all had positive correlations with relative humidity and negative correlations with wind speed. 展开更多
关键词 optical properties fine particulate matter meteorological conditions
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Geomechanical and water vapor absorption characteristics of clay-bearing soft rocks at great depth 被引量:1
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作者 Zhang Na Liu Longbiao +2 位作者 Hou Dongwen He Manchao Liu Yilei 《International Journal of Mining Science and Technology》 SCIE EI 2014年第6期811-818,共8页
The geological and physico-mechanical properties characterization of deep soft rocks is one of the critical scientific issues for deep soft rock engineering. In the present study, X-ray diffraction(XRD) analysis,scann... The geological and physico-mechanical properties characterization of deep soft rocks is one of the critical scientific issues for deep soft rock engineering. In the present study, X-ray diffraction(XRD) analysis,scanning electron microscope(SEM), and mercury intrusion porosimetry experiments were carried out to investigate the mineral compositions, microstructure and porosity characteristics of the 13 claybearing soft rock samples collected from a deep coal mine in China. Water vapor absorption and uniaxial compressive experiments were also performed to examine water absorption characteristics and waterinduced strength degradation effect of the investigated deep soft rock samples. The results show that the dominant mineral components in mudstone, coarse sandstone and fine sandstone samples were calcite, quartz and clay respectively. The contents of clay minerals in all samples were relatively high and ranged from 12.3%(N-4) to 56.5%(XS-1). Water vapor absorption processes of all the soft rock samples follow an exponential law which is very similar to the water vapor absorption behavior of conglomerate samples reported in our earlier study. Correlation analyses also suggested that there were good positive correlation relationships between water absorptivity and clay minerals for both mudstone and sandstone samples. Furthermore, it was found that vapor absorption was not correlated with the porosity for mudstone, however, positive correlation relationship was found between them for sandstone. Correlation analysis between UCS, modulus of elasticity and water content demonstrated that both of them tend to decrease with the increase of their water content due to water absorption. 展开更多
关键词 Soft rock Clay minerals Microstructure Vapor absorption Strength degradation
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Petrological characteristics,geochemical feature and metallogenetic relation of alkaline-rich rocks in northwest of Yunan Province,China
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作者 张德贤 戴塔根 《Journal of Central South University》 SCIE EI CAS 2011年第4期1217-1225,共9页
The alkali-rich rocks, spreading along the suture zone of Jingsha River, refer to the alkali-rich porphyry rocks, which emplace during the Himalaya epoch in northwest of Yunnan Province, and consist of syenit, syenit ... The alkali-rich rocks, spreading along the suture zone of Jingsha River, refer to the alkali-rich porphyry rocks, which emplace during the Himalaya epoch in northwest of Yunnan Province, and consist of syenit, syenit porphyry, monzonite porphyry and granite porphyry. Petrological chemical analysis results suggest that silica is poor and aluminum is rich, and high potassium large ion lithophile elements (LILE), light rare earth element (LREE) and Sr are obviously detracted in these rocks. High field strength elements (HFSE) and heavy rare earth element (HREE) are depleted, especially Nb, Ta, P and Ti. 8Eu: 0.09--1.64 shows that plagioclase does not appear fractional crystallization during the formation of alkali-rich rocks, t^348, H and O isotopes and Pb isotopes suggest that ore-forming fluid is derived from the mantle, and Pb is possibly mixed by mantle, wall rock and crust. The age of Pb in alkali-rich rocks is about 250-220 Ma. The age of alkali porphyry rock (dykes) varies from 30 Ma to 50 Ma. Alkali rocks have strong metallogenetic relation. Au mineralization is associated to the alkali magrnatic activities with a relatively high temperature, low pressure and high oxygen fugacity. However, copper mineralization is mainly associated with alkali-sub-alkali magmatic activities in a process of relatively low temperature, high pressure and lower oxygen fugacity. 展开更多
关键词 alkali-rich porphyry rocks Sanjiang metallogenetic belt GEOCHEMISTRY metallogenetic relation
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Tectonic evolution and the analysis of unfavorable geology in a tunnel
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作者 WANG Jin-shan WANG Li +3 位作者 LI Yong ZHANG Yan-xin CAO Zhi-gang LI Chun-liu 《Journal of Coal Science & Engineering(China)》 2009年第4期374-381,共8页
Based on the theory of geomechanics and using geologic analytical methods,analyed the fault characteristics, mechanical properties, displacement mode, tectonic system, structural pattern, activity mode of stress, tect... Based on the theory of geomechanics and using geologic analytical methods,analyed the fault characteristics, mechanical properties, displacement mode, tectonic system, structural pattern, activity mode of stress, tectonic activity, and tectonic evolution ofthe area of the Xiamen submarine tunnel, the strike NWW 295^(。), which is the main unfavorable geological structure that affects the safety of the tunnel construction; the macrogeological prediction concludes that weathered troughs and groundwater-rich zonesformed by its larger-scale fault fracture zones are the main unfavorable geological bodiesprovides a basis for preventing the geo-logical hazards in the tunnel construction. 展开更多
关键词 TUNNEL tectonic evolution unfavorable geological body macro geological prediction geological analytical method
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Development and Prospect of Study on Soil Nonlinear Dynamic Characteristics under Strong-Motion 被引量:1
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作者 Wang Yushi Li Xiaojun +2 位作者 Lan Riqing Wang Ning Chen Hongjuan 《Earthquake Research in China》 CSCD 2017年第1期12-24,共13页
Ground motions are significantly influenced by dynamic characteristics of overburden soil layers near ground surface,as thick and soft soil layers would obviously amplify the ground motion strength. The conventional r... Ground motions are significantly influenced by dynamic characteristics of overburden soil layers near ground surface,as thick and soft soil layers would obviously amplify the ground motion strength. The conventional research method on soil nonlinear dynamic characteristics under strong motions is based on experiments in laboratories for the deficiency of observation data,but it is difficult to reliably simulate the complex factors of soils in actual earthquake durations,including loading paths,boundary conditions,and drainage conditions. The incremental data of the vertical downhole observation array,which is comprised of at least one observation point on ground surface and one observation point in a downhole rock base, makes it possible to study soil nonlinear dynamics according to in situ observation data,and provides new basic data and development opportunities to soil nonlinear dynamics studies. 展开更多
关键词 Strong-motion Soil dynamics Local site effect Strong-motion observation Vertical array record
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Hydrodynamic characteristics of Wujiangdu Reservoir during the dry season-a case study of a canyon reservoir 被引量:1
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作者 Haitao Zhang Baoli Wang +3 位作者 Qiong Han Jie Shi Xiaolong Qiu Tiejun Wang 《Acta Geochimica》 EI CAS CSCD 2017年第3期506-510,共5页
With the development of hydropower in the karst area of Southwest China, a series of cascade canyon reservoirs have been formed through the construction of dams. Given that hydrodynamic conditions in canyon reservoirs... With the development of hydropower in the karst area of Southwest China, a series of cascade canyon reservoirs have been formed through the construction of dams. Given that hydrodynamic conditions in canyon reservoirs play a pivotal role in controlling the spatiotemporal distribution of physical and chemical properties of the stored water, hydrodynamic characteristics are of great importance in understanding biogeochemical cycles in those reservoirs. To further this understanding, a field campaign was conducted in the Wujiangdu Reservoir of Guizhou Province. It was found that from the reservoir inlet to the front of the dam, velocity(v) was negativelycorrelated and had a logarithmic relationship with distance along the ship track(s) under dry-season flow conditions[v =-0.104 ln(s) + 0.4756]. Analysis showed that dryseason flow velocity had no significant correlation with water temperature, p H, or dissolved oxygen(DO). However, when velocity decreased to 0.061 m/s, water depth increased abruptly. In addition, DO displayed a sudden drop and the trend in p H changed from increasing to decreasing, while water temperature showed an opposite trend, indicating the existence of a transition zone from the river to the reservoir. 展开更多
关键词 Canyon reservoir Hydrodynamic characteristics A transition zone Wujiang River
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Characteristics of Heavy Metal Circulation in Biosphere
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作者 Dewu ZENG Kailin ZHU Xiaodong PEI 《Agricultural Science & Technology》 CAS 2014年第4期642-647,共6页
In order to control heavy metal pollution effectively, this paper reviews heavy metal source and transport characteristics in heavy metal circulation in bio- sphere, including geochemical cycle and biological cycle of... In order to control heavy metal pollution effectively, this paper reviews heavy metal source and transport characteristics in heavy metal circulation in bio- sphere, including geochemical cycle and biological cycle of heavy metals. The inter- body of geochemical cycle of heavy metals includes soil, gas as well as water body, and the interbody of biological cycle of heavy metals includes environment, plant, microorganisms and animals. As to macro-cycle, transportation character in each interbody is different. Heavy metal circulation in different interbody interacts with each other and is in dynamic balance. Heavy metals in soil include two parts, i.e. active and inert forms, which are in dynamic equilibrium. This equilibrium may be affected by different physicochemical factors. Heavy metal content at different soil depth reflects historical accumulation level of heavy metal. In contrast to agri- cultural eco-system itself, industrial and urban activities are of great menace. Fluvial transport and atmospheric input are significant pathways of heavy metal circulation. Sludge plays an accumulative role of heavy metals, and can release its heavy met- als to water body causing secondary pollution. Balance of heavy metal immobiliza- tion and release is interrupted by physicochemical characters and microbial activity. Temperature can influence atmospheric heavy metal content, and volatile heavy meal precipitation is an indLspensable source in soil and water body. In regard to micro-cycle, plants is the main part in heavy metal cycle, microorganisms play roles in accelerator and animals in recipient. Specific transportation and assigned location of heavy metal in plants are adopted to keep internal heavy metal equilibrium. 展开更多
关键词 Heavy metal Geochemical cycle Biological cycle Transport process
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Empirical modeling of nonlinear and hysteresis characteristics of the shock absorber
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作者 崔岩 Sun Fengchun 《High Technology Letters》 EI CAS 2013年第3期267-272,共6页
An empirical hybrid shock absorber model capable of capturing nonlinear and hysteresis characteristics of shock absorbers is built.The nonlinear characteristics are modeled by algebraic function and the hysteresis eff... An empirical hybrid shock absorber model capable of capturing nonlinear and hysteresis characteristics of shock absorbers is built.The nonlinear characteristics are modeled by algebraic function and the hysteresis effects between shock force and shock velocity are modeled by neural network.To develop the empirical hybrid shock absorber model,a Mazda CX-7 front shock absorber is tested by a displacement-controlled hydraulic shock absorber testing machine.The hybrid shock absorber model is built and validated using the experimental shock absorber data.The RMS value for the hybrid shock absorber model is 60.28N at the velocity range from-1.3m/s to 1.3m/s. 展开更多
关键词 shock absorber NONLINEARITY HYSTERESIS vehicle dynamics
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Progress and perspective on frontiers of geobiology 被引量:11
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作者 XIE ShuCheng YIN HongFu 《Science China Earth Sciences》 SCIE EI CAS 2014年第5期855-868,共14页
Geobiology is a new discipline on the crossing interface between earth science and life science, and aims to understand the in- teraction and co-evolution between organisms and environments. On the basis of the latest... Geobiology is a new discipline on the crossing interface between earth science and life science, and aims to understand the in- teraction and co-evolution between organisms and environments. On the basis of the latest international achievements, the new data presented in the Beijing geobiology forum sponsored by Chinese Academy of Sciences in 2013, and the papers in this special issue, here we present an overview of the progress and perspectives on three important frontiers, including geobiology of the critical periods in Earth history, geomicrobes and their responses and feedbacks to global environmental changes, and geobiology in extreme environments. Knowledge is greatly improved about the close relationship of some significant biotic events such as origin, radiation, extinction, and recovery of organisms with the deep Earth processes and the resultant envi- ronmental processes among oceans, land, and atmosphere in the critical periods, although the specific dynamics of the co-evolution between ancient life and paleoenvironments is still largely unknown. A variety of geomicrobial functional groups were found to respond sensitively to paleoenvironmental changes, which enable the establishment of proxies for paleoenvi- ronmental reconstruction, and to play active roles on the Earth environmental changes via elemental biogeochemical cycles and mineral bio-transforrnations, but to be deciphered are the mechanisms of these functional groups that change paleoenvi- ronmental conditions. Microbes of potential geobiology significance were found and isolated from some extreme environments with their biological properties partly understood, but little is known about their geobiological functions to change Earth envi- ronments. The biotic processes to alter or modify the environments are thus proposed to be the very issue geobiology aims to decipher in the future. Geobiology will greatly extend the temporal and spatial scope of biotic research on Earth and beyond. It has great potential of application in the domains of resource exploration and global change. To achieve these aims needs coor- dinative multidisciplinary studies concerning geomicrobiology and related themes, database and modeling of biogeochemical cycles, typical geological environments, and coupling of biological, physical, and chemical processes. 展开更多
关键词 microbial functional group extreme environment biotic crisis PALEOBIOLOGY
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Relationship of atmospheric boundary layer depth with thermodynamic processes at the land surface in arid regions of China 被引量:30
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作者 ZHANG Qiang ZHANG Jie +1 位作者 QIAO Juan WANG Sheng 《Science China Earth Sciences》 SCIE EI CAS 2011年第10期1586-1594,共9页
The atmospheric boundary layer (ABL) is an important physical characteristic of the Earth's atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mecha... The atmospheric boundary layer (ABL) is an important physical characteristic of the Earth's atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mechanisms. In this paper, the depth of the diurnal and nocturnal ABLs and their related thermodynamic features of land surface processes, including net radiation, the ground-air temperature difference and sensible heat flux, under typical summer and winter conditions are discussed on the basis of comprehensive observations of the ABL and thermodynamic processes at the land surface carried out in the extreme arid zone of Dunhuang. The relationships of the ABL depth in the development and maintenance stages with these thermodynamic features are also investigated. The results show that the depth of the ABL is closely correlated with the thermodynamic features in both development and maintenance stages and more energy is consumed in the development stage. Further analysis indicates that wind velocity also affects ABL development, especially the development of a stable boundary layer in winter. Taken together, the analysis results indicate that extremely strong thermodynamic processes at the land surface are the main driving factor for the formation of a deep ABL in an arid region. 展开更多
关键词 arid region deep atmospheric boundary layer development and maintenance thermodynamic process at the land surface main driving factor
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Dissolved barium as a tracer of Kuroshio incursion in the Kuroshio region east of Taiwan Island and the adjacent East China Sea 被引量:9
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作者 LIU Wei SONG JinMing +3 位作者 YUAN HuaMao LI Ning LI XueGang DUAN LiQin 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第7期1356-1367,共12页
From May to June 2014, the geochemical characteristics of dissolved barium(Ba) in sea water and its influx from the Kuroshio into the East China Sea(ECS) were studied by investigation of the Kuroshio mainstream east o... From May to June 2014, the geochemical characteristics of dissolved barium(Ba) in sea water and its influx from the Kuroshio into the East China Sea(ECS) were studied by investigation of the Kuroshio mainstream east of Taiwan Island and the adjacent ECS. This allowed for the scope and extent of the Kuroshio incursion to be quantitatively described for the first time by using Ba as a tracer. The concentration of Ba in the Kuroshio mainstream increased gradually downward from the surface in the range 4.91–19.2 μg L.1. In the surface layer of the ECS, the Ba concentration was highest in coastal water and gradually decreased seaward, while it was higher in coastal and offshore water but lowest in middle shelf for bottom layer. The influx of Ba from Kuroshio into the ECS during May to October was calculated to be 2.19×108 kg by a water exchange model, in which the subsurface layer had the largest portion. The distribution of Ba indicated that Kuroshio upwelled in the sea area northeast of Taiwan Island. The north-flowing water in the Taiwan Strait restrained the incursion of Kuroshio surface water onto the ECS shelf, while Kuroshio subsurface water gradually affected the bottom of the ECS from outside. The results of end member calculation, using Ba as a parameter, showed that the Kuroshio surface water had little impact on the ECS, while the Kuroshio subsurface water formed an intrusion current by climbing northwest along the bottom of the middle shelf from the sea area northeast of Taiwan Island into the Qiantang Estuary, of which the volume of Kuroshio water was nearly 65%. Kuroshio water was the predominant part of the water on the outer shelf bottom and its proportion in areas deeper than the 100 m isobath could reach more than 95%. In the DH9 section(north of Taiwan Island), Kuroshio subsurface water intruded westward along the bottom from the shelf edge and then rose upward(in lower proportion). Kuroshio water accounted for 95% of the ocean volume could reach as far as 122°E. Ba was able to provide detailed tracing of the Kuroshio incursion into the ECS owing to its geochemical characteristics and became an effective tracer for revealing quantitative interactions between the Kuroshio and the ECS. 展开更多
关键词 Dissolved barium TRACER Geochemical characteristics Kuroshio incursion The ECS shelf
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Dynamic mechanisms of earthquake-triggered landslides 被引量:8
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作者 ZHU ShouBiao SHI YaoLin +1 位作者 LU Ming XIE FuRen 《Science China Earth Sciences》 SCIE EI CAS 2013年第10期1769-1779,共11页
Earthquake-triggered landslides usually cause great disasters,and yet their dynamic mechanisms remain poorly understood.This paper will derive a general conceptual landslide model from the geometric and kinematic feat... Earthquake-triggered landslides usually cause great disasters,and yet their dynamic mechanisms remain poorly understood.This paper will derive a general conceptual landslide model from the geometric and kinematic features of the most landslide masses triggered by the 2008 Wenchuan earthquake.Kinematic characteristics and dynamic processes are simulated here by means of finite element method(FEM)based on the dynamic process of the discontinuous deformable body.The calculated results presented the whole course of landslide motion,and displayed some typical kinematic characteristics such as initiation,sliding,ejection,collision,flying in the air,and climbing of landslides.The simulation result also shows that,under combined seismic inertial forces and gravity,landslides will start to slip once it overcomes the friction between the sliding mass and slip-bed,then it will move from slow to fast along the slippery bed until it ejects from the slip-bed.Moreover,the high frequencies and serious damages by landslides in the Wenchuan earthquake are caused by the strong ground motion on the mountain slopes in and around the epicenter that was dramatically amplified owing to both resonances produced by the seismic event and topographical amplification by seismic motion.In addition,the modeling results suggest that the direction,amplitude,frequency,and duration of strong ground motion have a great influence on the stability of landslide mass.Therefore,the study helps us better understand dynamic mechanism of landslides,seismic hazard assessment,and dynamic earthquake triggering. 展开更多
关键词 earthquake-triggered landslides strong ground motion DYNAMICS finite element method Wenchuan earthquake
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Aerosol properties over an urban site in central East China derived from ground sun-photometer measurements
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作者 LIU Qi DING WeiDong +6 位作者 XIE Lei ZHANG JinQiang ZHU Jun XIA XiangAo LIU DongYang YUAN RenMin FU YunFei 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第2期297-314,共18页
Sun-photometer measurements at Hefei,an urban site located in central East China,were examined to investigate the variations of aerosol loading and optical properties.It is found that aerosol optical thickness(AOT)kee... Sun-photometer measurements at Hefei,an urban site located in central East China,were examined to investigate the variations of aerosol loading and optical properties.It is found that aerosol optical thickness(AOT)keeps higher in winter/spring and gets relatively lower in summer/autumn.The large AOT in winter is caused by anthropogenic sulfate/nitrate aerosols,while in spring dust particles elevate the background aerosol loading and the excessive fine-mode particles eventually lead to severe pollution.There is a dramatic decline of AOT during summer,with monthly averaged AOT reaching the maximum in June and soon the minimum in August.Meanwhile,aerosol size decreases consistently and single scattering albedo(SSA)reaches its minimum in July.During summertime large-sized particles play a key role to change the air from clean to mild-pollution situation,while the presence of massive small-sized particles makes the air being even more polluted.These complicated summer patterns are possibly related to the three key processes that are active in the high temperature/humidity environment concentrating on sulfate/nitrate aerosols,i.e.,gas-to-particle transformation,hygroscopic growth,and wet scavenging.Regardless of season,the increase of SSA with increasing AOT occurs across the visible and near-infrared bands,suggesting the dominant negative/cooling effect with the elevated aerosol loading.The SSA spectra under varying AOT monotonically decrease with wavelength.The relatively large slope arises in summer,reinforcing the dominance of sulfate/nitrate aerosols that induce severe pollution in summer season around this city. 展开更多
关键词 Aerosol optical thickness Single scattering albedo Central East China Sun-photometer
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Geochronology, geochemistry, and its geological significance of the Permian Mandula mafic rocks in Damaoqi, Inner Mongolia 被引量:31
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作者 CHEN Chen ZHANG ZhiCheng +3 位作者 GUO ZhaoJie LI JianFeng FENG ZhiShuo TANG WenHao 《Science China Earth Sciences》 SCIE EI CAS 2012年第1期39-52,共14页
The Hujierte-Chaganhadamiao volcanic-plutonic sequence is located in the Mandula area of northen Damaoqi, Inner Mongo- lia. It contains mainly mafic volcanics, with several ultramafic blocks in its central part and ma... The Hujierte-Chaganhadamiao volcanic-plutonic sequence is located in the Mandula area of northen Damaoqi, Inner Mongo- lia. It contains mainly mafic volcanics, with several ultramafic blocks in its central part and mafic- ntermediate intrusions in the east. The zircon U-Pb ages of the gabbro and basalt samples are 278.5±3.0 Ma (MSWD=).66) and 273.7±1.0 Ma (MSWD=0.36), respectively. These ages constrain the magmatism occurred in the Early Permian. The Mandula Permian mafic rocks are characterized by low abundances of REE and slightly LREE-enriched chondrite-normal zed N-MORB-type REE patterns. And these mafic samples have high (143Nd/144Nd)i (0.51262-0.51270), relatively high pos tive εNd(t) (3.4-8.0), and high Mg# (49-54), suggesting derivation from the depleted asthenosphere mantle source. But they al, show the enrichment in large ion lithophile elements (LILE, e.g. Rb, Ba and Sr), depletion in high field strength elements (I-FSE); distinctly negative Nb, Ta anomalies and slightly negative P, Ti anomalies; high (875r/86Sr)i (0.70490-0.70537), low (206pb/204pb)i (17.39-17.93). All of these resemble the characteristics of the enriched mantle source or involvement of arc materials in the magma genesis. Furthermore, as shown in the correlation plots of eNd(t) VS (87Sr/86Sr)i, (206pb/204Pb)ivs (207pb/204Pb)i and (208pb/204pb)i, La/Ba La/Nb vs La/Nb, and La/Nb ratio, the magma source could have been experienced the contamination and metasomation from the previous subduction process. And the positive correlation between the selected major oxides and trace elements could be explained by the contamination from continental crust and arc materials during the magmatic emplacement. Combined with the distinct geochemistry features of Mandula mafic samples and many previous researches in the study area, the Early Permian magmatism in Mandula occurred under an extensional rift setting, and a juvenile ocean basin probably had already been formed after further development. 展开更多
关键词 Mandula zircon SHRIMP U-Pb age PERMIAN GEOCHEMISTRY extensional setting
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Petrogenetic model of the Permian Tarim Large Igneous Province 被引量:7
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作者 YU Xing YANG ShuFeng +2 位作者 CHEN HanLin LI ZiLong LI YinQi 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第10期1805-1816,共12页
Over the last two decades great strides have been made in characterizing the spatial distribution, time sequence,geochemical characteristics, mantle sources, and magma evolution processes for various igneous rocks in ... Over the last two decades great strides have been made in characterizing the spatial distribution, time sequence,geochemical characteristics, mantle sources, and magma evolution processes for various igneous rocks in the Early Permian Tarim Large Igneous Province(TLIP). This work has laid a solid foundation for revealing the evolutionary processes and genetic models of large igneous provinces(LIPs). This study systematically demonstrates the two-stage melting model for the TLIP based on our previous research work and predecessor achievements, and highlights the two types of magmatic rocks within the TLIP.The two-stage melting model suggests that the formation of the TLIP is mantle plume related. The early hot mantle plume caused the low-degree partial melting of the lithosphere mantle, while in the later stage, the plume partially melted due to adiabatic uplift and decompression. Therefore, this model carries signatures of both the "Parana" and "Deccan" models in terms of mantle plume activity. During the early stage, the mantle plume provided the heat required for partial melting of sub-continental lithosphere mantle(SCLM), similar to the "Parana Model", while later the plume acted as the main avenue for melting, as in the "Deccan Model". Basalts that erupted in the first stage have higher 87Sr/86 Sr, lower 143Nd/144 Nd ratios, and are enriched in large ion lithophile elements and high field strength elements, indicating a possible origin from the enriched continental lithosphere mantle,similar to the Parana type geochemical features. The basic-ultrabasic intrusive rocks in the second stage exhibit lower 87Sr/86 Sr,higher 143Nd/144 Nd ratios relative to the basalts, consistent with the involvement of a more depleted asthenospheric material,such as a mantle plume, similar to the Deccan type geochemical features. The first stage basalts can be further subdivided into two categories, i.e., Group 1 and Group 2 basalts. Group 2 basalts have lower 87Sr/86 Sr and higher 143Nd/144 Nd ratios than Group 1 basalts, and lie between compositions of the Group 1 basalts and second stage magmatism. Group 2 basalts may be the intermediate component of the TLIP, and the whole TLIP is the result of plume and lithosphere interaction. Developing this petrogenetic model for the TLIP aids in comprehensively understanding its magmatism and deep geological and geodynamic processes. Furthermore, this work enriches the theories describing the origin of large igneous province and mantle plume activity. 展开更多
关键词 Large igneous province Early Permian Two types of basalts Petrogenetic model Tarim Basin
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