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Numerically quantifying the relative importance of topography and buoyancy in driving groundwater flow

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Science China earth sciences 2010年第1期53卷 64-71页

作者： YANG JianWen 1,2.FENG ZuoHai 1,LUO XianRong 1 & CHEN YuanRong 1 1 faculty of earth {2.,Guilin university of Technology,Guilin 54.004.China 2.Department of earth and Environmental {2.,university of Windsor,Windsor,Ontario,N9B 3P4.Canada 1. faculty of earth {2. Guilin University of Technology Guilin 541004 China2. Department of Earth and Environmental Sciences University of Windsor Windsor Ontario N9B 3P4 Canada

Both topography and buoyancy can drive groundwater flow;however,the interactions between them are still poorly *** this paper,the authors conduct numerical simulations of variable-density fluid flow and heat transport to quantify their relative *** finite element modeling experiments on a 2.D conceptual model reveal that the pattern of groundwater flow depends largely upon the relative magnitude of the flow rate due to topography alone and the flow rate due to buoyancy *** fluid velocity due to topography is greater than that due to buoyancy at large water table gradients,topography-driven 'forced convection' overwhelms buoyancy-driven 'free convection'.When flow velocity due to buoyancy is greater than that due to topography at small water table gradients,mixed free and forced convection takes *** this case,free convection becomes dominant,but topography-driven flow still plays an important role since it pushes the free convection cells to migrate laterally in the downhill ***,hydrothermal fluid flow remains changing periodically with time and no steady state can be *** presence of a low-permeability layer near the surface helps eliminate the topography effect on the underlying free convection.

关键词： hydrothermal flow free convection forced convection topography buoyancy finite element modeling

Development of distributed time-variant gain model for nonlinear hydrological systems

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Science China earth sciences 2005年第6期48卷 713-723页

作者： XIA Jun1, 2. WANG Gangsheng1, TAN Ge1, YE Aizhong2.& G. H. Huang3 1. Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, Beijing 100101, China 2. State Key Laboratory of Water Resources & Hydropower Engineering sciences, wuhan {4., wuhan 4.0072. China 3. faculty of Engineering, {4. of Regina, 3737 Wascana Parkway, Regina, Sask., S4. 0A2. Canada Correspondence should be addressed to Xia Jun 1. Key Laboratory of Water Cycle & Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. State Key Laboratory of Water Resources & Hydropower Engineering sciences Wuhan University 430072 Wuhan China 3. faculty of Engineering University of Regina 3737 Wascana Parkway S4S 0A2 Sask Regina Canada

In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and the distributed time-variant gain model (DTVGM) that are built on the platform of Digital Elevation Model (DEM), Remote Sensing (RS) and Unit Hydro-logical Process were proposed. The developed DTVGM model was applied to two cases in the Heihe River Basin that is located in the arid and semiarid region of northwestern China and the Chaobai River basin located in the semihumid region of northern China. The results indicate that, in addition to the classic dynamic differential approach to describe nonlinear processes in hy-drological systems, it is possible to study such complex processes through the proposed sys-tematic approach to identify prominent hydrological relations. The DTVGM, coupling the advan-tages of both nonlinear and distributed hydrological models, can simulate variant hydrological processes under different environment conditions. Satisfactory results were obtained in fore-casting the time-space variations of hydrological processes and the relationships between land use/cover change and surface runoff variation.

关键词： hydrological process, nonlinearity, time-variant gain model, distributed hydrological model.

Crustal　Texture　and　Rheological　Evolution　of　Tongbai－Dabie　Orogenic　Belt，China

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Journal of earth Science 1995年第1期14卷 59-63页

作者： Suo Shutian(faculty of earth {2., China university of {4., wuhan 4.0074.

The crustal texture and rheological evolution of the Tongbai-Dabie orogenic belt are approached from a physical standpoint on the basis of a large body of geological, chronological and geophysical data available in the region. Rheological profiles showing variation of rock Strength with depth in the continental crust are constructed for 1-D crustal structure limited to the Present and Meso-Neoproterozoic structural configurations of the deformed belt, respectively .It is emphasized that the crustal texture and composition have been heterogeneous with the rheological stratification and complicated rheological evolution since the Meso-Neoproterozoic at least. The data appear that the Tongbai - Dabie tectonic belt is a polyphase collisional orogen with evidence for cyclically transition from compressional to extensional regimes and rheological behavior in the levels of the crust.

关键词： orogenic belt Physical condition rheological Stratification fluid crustal layer paleorheological Profile.

Characteristics of Albaillella (Albaillellarian,Radiolarian) Fauna from Guadalupian to Lopingian Series in Permian,South China

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Journal of China university of geosciences 2003年第4期14卷 314-320页

作者： Sun Dongying Xia Wenchen faculty of earth {2., China university of {4., wuhan 4.0074 faculty of earth {2. China University of Geosciences Wuhan 430074

On the basis of establishment of radiolarian biostratigraphy and conodont biostratigraphy, a radiolarian Albaillella fauna in the transitional environment from Guadalupian to Lopingian Series in Permian was found at a pelagic chert section in southeast Guangxi, South China. Radiolarian Albaillella is one of the most sensitive biology to the transitional environment. The Albaillella fauna shows an ecological evolutionary process from Guadalupian to Lopingian: declined stage-recovery stage-flourishing stage. The study of characteristics of the Albaillella fauna in the transitional environment may provide more information, not only for the subdivision and correlation of a high-resolution biostratigraphy, but also for influence of radiolarian Albaillella fauna on the pre-Lopingian mass extinction.

关键词： Permian Guadalupian-Lopingian Series transitional environment radiolarian Albaillella fauna.

Laser Ablation ICP-MS Titanite U-Th-Pb Dating of the Tonglushan Cu-Fe-Au Skarn Deposit,Southeastern Hubei Province

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矿物学报 2009年第S1期29卷 314-316页

作者： LI Jian-wei 1,2.DENG Xiao-dong1,2.ZHOU Mei-fu3,LIU Yong-sheng1(1. State Key Laboratory of Geological Processes and Mineral Resources,China university of geosciences,{2. 4.0074.China 2. {4. of earth Resources,China university of geosciences,{2. 4.0074.China 3. Department of earth sciences,the university of Hong Kong,Hong Kong)

Titanite(CaTi2.iO5) is an important accessory mineral not only in magmatic and metamorphic rocks,but also commonly in hydrothermal mineral deposits. It incorporates appreciable amounts(usually 10×10-6 s to 100×10-6 s) of U and Th into its structure and has a closure temperature of Pb diffusion higher than 660～700 ℃(Scott and St-Onge,1995) ,making it an ideal U-Th-Pb geochronometer. The Daye metallogenic district is located in the west of the giant Middle-Lower Yangtze River(MLYR) Cu-Fe-Au province,eastern China and is well endowed with Fe,Cu,and polymetallic skarn deposits.

关键词： Pb Laser Ablation ICP-MS Titanite U-Th-Pb Dating of the Tonglushan Cu-Fe-Au Skarn Deposit,Southeastern Hubei Province Th Fe ICP Cu MS

Garnet-bearing Granulite Facies Rock Xenoliths from Late Mesozoic Volcaniclastic Breccia, Xinyang, Henan Province

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Acta Geologica Sinica(English Edition) 2001年第4期75卷 445-451页

作者： ZHENG Jianping, SUN Min, LU Fengxiang, WANG Chunyangand ZHONG Zengqiu faculty of earth {2., China university of {4., wuhan 4.0074. China Department of earth {2., The university of Hong Kong, China faculty of earth {2. China University of Geosciences Wuhan 430074 China Department of earth sciences The University of Hong Kong China [?]3Zheng Jianping Born in 1964 graduated from the China university of geosciences ({2.) with a PhD degree in 1997 mainly engaged in teaching and scientific researches on petrology and chemical geodynamics. E-mail: jpzheng@***.

This paper presents the primary results of petrologic, mineralogical and petrochemical studies of garnet-bearing granulite facies rock xenoliths from Xinyang, Henan Province. These xenoliths, which are found in a pipe of late Mesozoic volcaniclastic breccia, are of high density (3.13–3.30 g/cm3) and high seismic velocity (Vp = 7.04.7.31 km/s), being products of underplating of basaltic magmas and had experienced granulite facies metamorphism. The underplating and metamorphism took place before the eruption of the host rock. Petrographical studies and equilibrium T-P calculations show that these xenoliths were captured at a 4. km depth and experienced at least a 16 km uplift before they were captured. The dynamics of the uplift could be related to the continent-continent collision between the North China plate and the Yangtze plate during the Triassic.

关键词： granulite facies mafic rock xenolith uplift Xinyang

Genomics,metagenomics,and microbial oceanography—A sea of opportunities

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Science China earth sciences 2011年第4期54卷 473-480页

作者： FANG JiaSong 1,2.&ZHANG Li 3 1 State Key Laboratory of Marine Geology,Tongji university,Shanghai 2.0092.China 2.College of Natural and Computational sciences,Hawaii Pacific university,Kaneohe,HI 9674.,USA 3State Key Laboratory of Geological Processes and Mineral Resources,faculty of {4. sciences,China university of geosciences,wuhan 4.0074.China 1. State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China2. College of Natural and Computational Sciences Hawaii Pacific University Kaneohe HI 96744 USA3. State Key Laboratory of Geological Processes and Mineral Resources Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China

Microbial oceanography is an emerging discipline resulted from the interaction,cross-fertilization and integration of life science and ocean *** oceanography integrates the principles of marine microbiology,microbial ecology and oceanography to study the role of microorganisms in the biogeochemical dynamics of natural marine *** application of genomics tools to study marine microbes is resulting in rapid advancements in microbial oceanography that has important implications in global carbon cycle,climate change,and ecosystem *** we review the application of genomics and metagenomics in microbial oceanography and suggest future directions in microbial oceanography research.

关键词： microbial oceanography genomics metagenomics genes biomass bacteria archaea eukarya phylogeny physiology metabolism ecology biogeochemistry microbiology ecosystem function

Characteristics of Coal Accumulation of Transform-Extensional Basins in Linear Fracture Zones: A Case Study of the Meihekou Basin

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Acta Geologica Sinica(English Edition) 1999年第1期73卷 104-110页

作者： ZHUANG Xinguo Institute of Sedimentary Basin, faculty of earth Resources China {2. of geosciences, {4., Hubei 4.0074 China Univ Geosci Fac Earth Resources Inst Sedimentary Basin Wuhan 430074 Hubei Peoples R China

This paper discusses the characteristics of coal accumulation of transfor-extensional basins in linear fracture zones on the basis of an analysis of tectonic evolution and sequence stratigraphy in the Meihekou basin. Coal accumulation of the basin occurred mainly in the accelerated rifting period of the transtentional regime and in the late period of tectonic transformation of the transpressional regime. In the former period, swamps developed in shallow lakes. The thickness of coal seams was controlled by the activity of fault block. Thick coal was formed in a downfaulted trough. In the latter period, swamps developed in a braided fan delta plain. The coal seams are thin and have poor lateral continuity. The thickness of coal seams was controlled by the migration of water channels in the braided plain.

关键词： coal accumulation sequence stratigraphy tectonic evolution Meihekou basin

Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

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Science China earth sciences 2006年第9期49卷 904-914页

作者： WANG Xiaorui1, GAO Shan1,2. LIU Xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3 & WANG Xuance4.1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest university, Xi`an 710069, China 2. State Key Laboratory of Geological Processes and Mineral Resources, China university of geosciences, wuhan {4. China 3. Shenyang Institute of Geology and Mineral Resources, Shenyang 110032. China 4. Guangzhou Institute of Geochemistry, Chinese Academy of sciences, Guangzhou 51064., China 1. State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China 2. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 3. Shenyang Institute of Geology and Mineral Resources Shenyang 110032 China 4. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2.= 52.82.59.31 wt%, Al_2._3=14.15-16.35wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03-1.88 μg/g) and Y(12.2. μg/g) and high Sr (62.-132. μg/g) and Sr/Y(32.88), withhigh La_N/Yb_N ratio (10-2.). They share similar major and trace element characteristics to volcanicrocks from the Xinglonggou Formation except their lower Nd isotope ratios (^(14.)Nd/^(14.)Nd(130Ma) = 0.5118-0.5119, ε_(Nd) (130Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (130 Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North China craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the Xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 12. to 130 Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2.for samples with SiO_2.> 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North China Craton, delamination.