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Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern china

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Science china earth Sciences 2005年第9期48卷 1463-1469页

作者： XIE Shucheng1,HUANG Junhua1,WANG Hongmei2.YI Yi1,HU Chaoyong1, CAI Yanjun3 & CHENG Hai4.1. Faculty of earth Science,china university of geosciences,{2. 2. School of Environmental Studies,china university of geosciences,{2. 3. SKLLQG,Institute of earth Environment,Chinese Academy of Sciences,Xi’an 710075,china 4. Department of Geology and Geophysics,university of Minnesota,MN554.5,USA 1. Faculty of earth Science China University of Geosciences 430074 Wuhan China 2. School of Environmental Studies China University of Geosciences 430074 Wuhan China 3. SKLLQG Institute of Earth Environment Chinese Academy of Sciences 710075 Xi’an China 4. Department of Geology and Geophysics University of Minnesota 55455 MN USA

Fatty acids extracted from a subtropical stalagmite at Qingjiang in Southern china’s Hubei Province were analysed using gas chromatography-mass spectrometry. These n-alkanoic acids range from C14.to C2. in carbon number, maximizing at C16, with a second dominance at C2.. In contrast to the stalagmite analysed, the overlying soils are characterized by the dominance of heavy-molecular-weight homologues (>C2.). The n-fatty acids in the stalagmite were proposed to be contributed by both the soil ecosystems and the microbes harboring in the percolating water and the cave. The ratios of unsaturated to saturated n-fatty acids (C16:1i/C16:0, C18:1/C18:0) appear to show trends comparable with the oxygen isotope records of the stalagmite carbonate, with enhanced values associated with the cold episode such as Heinrich event 1. This paleoclimate-dependent record of the n-fatty acids might reflect microbial changes in physiology and activity in response to the temperature. This record shows somewhat difference from the previous paleoclimate signal extracted from n-alkanols and n-alkan-2.ones of the same stalagmite. The acid record fails to document the well-known Younger Dryas event which was effectively shown by the latter two biomarkers derived from soil ecosystems. This discrepancy might result from the changing biogeochemical impact on different lipid fractions as well as the varied organism populations in different ecosystems.

关键词： biomarker, ecosystem, microbe, speleothem, paleoclimate, Quaternary.

Analysis on the long term discharge of a catchment

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Journal of Environmental Sciences 2000年第3期12卷 279-285页

作者： HONG Lin 1, TAKASE Keiji 2. SATO Koichi 2.(1. wuhan university of Hydraulic and Electric Engineering, wuhan 4.0072. china 2. Ehime university, Japan) wuhan university of Hydraulic and Electric Engineering Wuhan 430072 China Ehime university Japan

In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2.Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristics of the model simulations of the discharge of the catchment are analyzed and compared with those of a forest catchment.

关键词： long term discharge model simulation terraced paddy field catchment

Anatexis in Himalayan crust:Evidence from geochemical and chronological investigations of Higher Himalayan Crystallines

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Science china earth Sciences 2005年第9期48卷 1347-1356页

作者： YANG Xiaosong1, JIN Zhenmin2.& MA Jin1 1. State Key Laboratory of earthquake Dynamics, Institute of Geology, china earthquake Administration, Beijing 10002., china 2. Faculty of earth Sciences, china university of geosciences, wuhan 4.0074, china 1. State Key Laboratory of earthquake Dynamics Institute of Geology China Earthquake Administration 100029 Beijing China 2. Faculty of earth Sciences China University of Geosciences 430074 Wuhan China

Migmatization in Higher Himalayan Crystallines (HHC) results from anatexis. The widely distributed migmatites in HHC are an important clue to investigate the relationship be- tween anatexis and the origins of Higher Himalayan leucogranites (HHL), and to understand the effect of anatexis on crustal evolution during the post-collision period. We studied in detail the chemical features of three basic constituent parts of the migmatites, i.e. leucosome, mesosome and melanosome, and determined the K-Ar ages of leucosomes. Our studies indicate that type-I leucosome is the product of crystallization of melt generated by partial melting of mesosome at source region, but type-II leucosome and HHL probably underwent crystallization differentiation of plagioclase during melt aggregation and migration. The age of 2..67 Ma of Type-I leucosome, which is a little older than the beginning of MCT movement, indicates that anatexis may have played an important role in the formation of MCT. That the ages of type-II leucosome (ranging from 14.82.to 18.37 Ma) are consistent with that of HHL provides new chronological evidence for the relationship between migmatization and HHL. We obtained a very young age of 6.2. Ma of Type-II leucosome that provides new time constraint on magma activity in the central segment of Higher Himalayas.

关键词： Higher Himalayan Crystallines, migmatite, anatexis, leucosome, K-Ar age.

Seabed Classification Using BP Neural Network Based on GA

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Acta Oceanologica Sinica 2003年第4期22卷 523-531页

作者： Yang Fanlin1, Liu Jingnan2.1. GPS Engineering Research Center, wuhan university, wuhan 4.0079, {4.. 2. Presidential Secretariat, wuhan university, wuhan 4.0079, {4. wuhan Univ GPS Engn Res Ctr Wuhan 430079 Peoples R China

Side scan sonar imaging is one of the advanced methods for seabed study. In order to be utilized in other projects, such as ocean engineering, the image needs to be classified according to the distributions of different classes of seabed materials. In this paper, seabed image is classified according to BP neural network, and. Genetic Algorithm is adopted in train network in this paper. The feature vectors are average intensity, six statistics of texture and two dimensions of fractal. It considers not only the spatial correlation between different pixels, but also the terrain coarseness. The texture is denoted by the statistics of the co-occurrence matrix. Double Blanket algorithm is used to calculate dimension. Because a uniform fractal may not be sufficient to describe a seafloor, two dimensions are calculated respectively by the upper blanket and the lower blanket. However, in sonar image, fractal has directivity, i. e. there are different dimensions in different direction. Dimensions are different in acrosstrack and alongtrack, so the average of four directions is used to solve this problem. Finally, the real data verify the algorithm. In this paper, one hidden layer including six nodes is adopted. The BP network is rapidly and accurately convergent through GA. Correct classification rate is 92.5 % in the result.

关键词： BP network co-occurrence matrix fractal classification genetic algorithin

Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South china

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Science china earth Sciences 2006年第3期49卷 225-241页

作者： ZUO Jingxun1,2. TONG Jinnan3, QIU Haiou4.& ZHAO Laishi3 1. Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 2.0008, china 2. Henan Institute of Geological Survey, Zhengzhou 4.0007, china 3. State Key Laboratory of Geological Processes and Mineral Resources at {2., wuhan 4.0074, china 4. Faculty of Material Sciences and Chemical Engineering, {2., wuhan 4.0074, china 1. Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Henan Institute of Geological Survey Zhengzhou 450007 China 3. State Key Laboratory of Geological Processes and Mineral Resources at china university of geosciences Wuhan 430074 China 4. Faculty of Material Sciences and Chemical Engineering China University of Geosciences Wuhan 430074 China

Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South china, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13C background values are intensively controlled by palaeogeographic environment. In general, δ 13C values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in marine sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the Induan- Olenekian boundary and the Lower Triassic-Middle Triassic boundary.

关键词： Lower Triassic, carbon isotope compositions, palaeogeography, volcanic eruptions, Lower Yangtze Region.

Relationships between bacterial-algal proliferating and mass extinction in the Late Devonian Frasnian-Famennian transition:Enlightening from carbon isotopes and molecular fossils

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Science china earth Sciences 2005年第10期48卷 1656-1665页

作者： GONG Yiming1,2. XU Ran1, TANG Zhongdao1, SI Yuanlan3 & LI Baohua4.1. Faculty of earth Science and State Key Laboratory of Geological Processes and Mineral Resources, china university of geosciences, {2. {4., china 2. Institute of Resources & Environments, Henan Polytechnic university, Jiaozuo 4.4.03, china 3. Department of Computer Science, South-Central university for Nationalities, {2. {4., china 4. Laboratory of Marine Geology, Tongji university, Shanghai 2.0092. china Faculty of earth Science and State Key Laboratory of Geological Processes and Mineral Resources china university of geosciences {2. china Institute of Resources & Environments Henan Polytechnic university Jiaozuo china Department of Computer Science South-Central university for Nationalities wuhan {2. Laboratory of Marine Geology Tongji university Shanghai china

Studies show positive shifts of inorganic and organic carbon isotope values (δ 13Ccarb and δ 13Ckerogen) from +0.4. (‰ V-PDB) to +3.54.(‰ V-PDB) and from ?2..38 (‰ V-PDB) to ?2..14.(‰ V-PDB), respectively, B* (Ba* = Ba/ (Al2.3 X 15%)) values from 0.015 to 0.14., TOC values from 0.02. to 0.2.%, V/Cr values from 0.3 to 2.0, Sr/Ba values from 3.2. to 4..50 in the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone of the Yangdi sec-tion deposited in carbonate slope facies of Guilin, Guangxi, South china, which indicates that biomass, productivity, organic carbon burial and salinity increase and that oxygenation near the boundary between sediments and waters decreases from the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone. Abundance of molecular fossils increases and normal alkanes, isoprenoid hydrocarbon, terpanes and steranes are dominated from the Late Devonian Frasnian to the bottom of Famennian, which shows that the predecessors of molecular fossils of the Frasnian-Famennian (F-F) transition are dominated by marine phytoplankton, zooplankton and benthic bacteria with no photosynthesis. Therefore, it is considered that the F-F transitional mass extinction with a multistage, selection and global synchronizing was caused by bacte-rial-algal proliferating, continuing deterioration of the shallow marine ecoenvironment of the mid-dle-lower latitudes. A simple cause and effect chain can be expressed as: appearance of seed plants and multi-storied forests → enhanced chemical and biochemical weathering and pe-dogenesis → wide development of soils → increasing riverine nutrient fluxes in epicontinental sea → from superoligotrophic to eutrophic in epicontinental sea → proliferating of marine phyto-plankton and zooplankton → frequent red tide and anoxia → mass extinction of shallow marine organisms in the middle-lower latitudes. It is worth notice that the factor drawdown of atmos-pheric Pco2. climatic cooling and sea level falling c

关键词： mass extinction, bacteria-algae, carbon isotopes, molecular fossils, biodiversity, Late Devonian, Guangxi, South china.

earthquake-controlled event deposits and its tectonic significance from the Middle Permian Wandrawandian Siltstone in the Sydney Basin, Australia

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Science china earth Sciences 2005年第9期48卷 1337-1346页

作者： DU Yuansheng1, G. R. Shi1,2.& GONG Yiming1 1. Faculty of earth Sciences, china university of geosciences, {2. {4., china 2. School of Ecology and Environment, Deakin university, Victoria 312., Australia 1. Faculty of earth Sciences China University of Geosciences 430074 Wuhan China 2. School of Ecology and Environment Deakin University 3125 Victoria Australia

The Sydney-Bowen basin in eastern Australia is an elongate back arc-converted foreland basin system situated between the Lachlan Fold Belt in the west and the New England Fold Belt in the east. The Middle Permian Wandrawandian Siltstone at Warden Head near Ulla- dulla in the southern Sydney Basin is dominated by fossiliferous siltstone and mudstone, with a large amount of dropstones and minor pebbly sandstone beds. Two general types of deposits are recognized from the siltstone unit in view of the timing and mechanism of formation. One is rep- resented by the primary deposits from offshore to subtidal environments with abundant drop- stones of glacial marine origin. The second type is distinguished by secondary, soft-sediment deformational deposits and structures, and comprises three layers of mudstone dykes of seismic origin. In the latter type, metre scale, laterally extensive syn-depositional slump deformation structures occur in the middle part of the Wandrawandian Siltstone. The deformation structures vary in morphology and pattern, including large-scale complex-type folds, flexural stratification, concave-up structures, faulting of small displacements accompanied by folding and brecciation. The slumps and associated syn-sedimentary structures are attributed to penecontemporaneous deformations of soft sediments (mostly silty mud) formed as a result of mass movement of un- consolidated and/or semi-consolidated substrate following an earthquake event. The occurrence of the earthquake event deposits supports the current view that the Sydney Basin was located in a back-arc setting near the New England magmatic arc on an active continental margin during the Middle Permian.

关键词： Permian, seismites, earthquake, tectonics, Sydney Basin, Australia.

Lithospheric seismic fabrics of Sulu ultrahigh-pressure metamorphic belt

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Science china earth Sciences 2005年第5期48卷 585-600页

作者： YANG Wencai 1 , YANG Wuyang 1 , JIN Zhenmin 2.& CHENG Zhenyan 1 1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, china 2. china university of geosciences, {2. 4.0074, china 1. Chinese Academy of Geological Sciences Institute of Geology 100037 Beijing China 2. china university of geosciences 430074 Wuhan China

Calibration of seismic reflectors appearing in the crust of the Chinese continent sci- entific drilling site can be completed through the correlation studies between direct evidences, such as the drill cores, and geophysical signatures; therefore the interpretation of geophysical data could produce reliable results of crustal structure and composition. On the other hand, there are two Cenozoic volcanoes close to the scientific drilling site; analyzing composition of xenoliths existent in the volcanoes and evaluating their seismic velocities can also offer information about the mantle and lower crust. After the calibration via cores and well-logging data, the seismic re- flectors appearing in the UHP belt can be caused by lithological changes within the UHP rock slice, ductile shearing rock-suites, and later fracture zones. Among these sources, ductile shearing resulted in displacement and detachment of original rock-sheets, producing some rock-interbeds of several hundred meters thick that are named the ductile shearing rock-suites. A suite consists of mylonized gneiss and eclogite slices that underwent shearing, becoming the major mechanism responsible to generate regional strong reflections. The UHP rock-slice is characterized by complicated structures and high density, high seismic velocity and high electri- cal resistivity, its thickness is usually less than 11 km. Velocity and density of the gneiss-layer beneath gradually tend to normal with increasing depth. Based on the xenoliths we can infer that the middle crust contains a lot of gneisses, and the lower crust consists of different granulites. The lithospheric mantle has multi-layer structures and consists mainly of spinal lherzolite and harzburgite, implying late Mesozoic lithospheric thinning. The seismic fabrics with different ori- gins were possible products of different geodynamic processes. For instance, the UHP rock-slice was produced by the UHP metamorphic process and the exhumation of subducted supe

关键词： deep seismic reflection, ultrahigh-pressure belt, Sulu china, calibration of reflectors, lithospheric fabrics.

Pioneer organisms after F-F mass extinction in Dushan region,Guizhou Province,and their significance in establishing new ecosystem

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Science china earth Sciences 2006年第5期49卷 449-460页

作者： WANG Yue1, 2. WANG Xunlian1 & SHI Xiaoying1 1. School of earth Sciences and Resources, china university of geosciences, Beijing 100083, {2. 2. School of Resources and Environment, Guizhou university, Guiyang 550003, {2. 1. School of earth Sciences and Resources China University of Geosciences Beijing 100083 China 2. School of Resources and Environment Guizhou University Guiyang 550003 China

After mass extinctions, most areas became “ecologically barren areas” lacking or even without ecosystem over an extensive region. Studying the pioneer organisms and the reconstruction process of a new ecosystem in the “ecologically barren area” is very important for revealing the evo- lution after bio-mass extinctions. In the Dushan region, Guizhou Province, china, the trace fossils appeared and flourished evidently earlier than body fossils after Frasnian-Famennian (F-F) mass extinction. The pioneer organisms and pathfinders in the “ecologically barren areas” are the trace-makers that are deposit-feeders with relatively simple structure and conformation on or near the deposit surface. The trace-makers have undergone an evolutionary process that their trace structures changed from simple to complex, and their living and moving areas and spaces enlarged from linear to planar and then to three-dimension spaces. Those characters show that the ability of the trace-makers to deposits and their efficiency of looking for food have been enhanced gradually and that those trace-makers constructed gradually a base for the new ecosystem. This process is similar to that of the trace fossils near the Precambrian-Cambrian boundary. In the Dushan area, only the recovery intervals have been identified for the Famennian body fossils, with no eminent radiation interval recognizable due to the Devonian-Carboniferous (C-D) mass ex- tinction. However, both the recovery and radiation intervals may be clearly recognized in the Famen- nian trace fossils based on their conformation and diversity. The evolution and diversification of the trace fossils in the “ecologically barren area” is considered to have played a role of necessary foun- dation for the recovery of body fossils in the ecological chain. With the gradual disappearance of the unfavourable environment factors resulting in the F-F mass extinction, a new ecosystem was reconstructed in the “ecologically barren area” through a three-

关键词： pioneer organisms, reconstruction of ecosystem, trace fossils, F-F mass extinction, Later Devonian, Dushan region, Guizhou Province, china.