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Sample records for basin south china

  1. Tectonics and Sedimentary Basins of the South China Sea: Challenges and Progresses

    Institute of Scientific and Technical Information of China (English)

    Zhou Di; Yao Bochu

    2009-01-01

    @@ The special issue "Tectonics and Sedimentary Basins of the South China Sea" consists of 19 articles arranged in the order of deep structure,general tectonics,tectonic modeling,and sedimentary basins especially the deepwater sedimentary basins.

  2. Profiler-sonobuoy measurements in the South China Sea basin

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, W.J.; Kumar, N.; Houtz, R.E.

    1979-07-10

    Analyses of single-channel seismic reflection profiles, and wide-angle reflection and refraction data from sonobuoys, indicate that the deep part of the South China Sea basin is typically oceanic in structure, except that layer 2 is about 1 km thicker than usual and layer 3 is only about half the usual thickness. The top of layer 2 has a rough upper surface and becomes deeper in the northern part of the basin, where it is overlain by sediments of velocity 1.7--3.8 km/s up to 3 km thick. A 6-km-thick sequence of sediments fills a basement depression just north of the outer subsurface (peripheral) ridge of the Sunda shelf. Thick sediments were measured at the outer parts of the Sunda shelf, Palawan shelf, Northeast Borneo shelf, and in the Taiwan straits south of the Penghu-Peikang basement high. The Manila trench is divided into two sections, a sediment-filled trench between southernmost Taiwan and Stewart bank off central northern Luzon and a topographic trench between Stewart bank southward into the Mindoro straits. Burial of part of the trench by sediments that thicken to the north and the thick sediment cover of the northern South China Sea basin indicate provenance from the north. The northern margin of the South China Sea basin is predominantly a zone of tension the southern margin is predominantly a zone of compression, the western margin may be a zone of shear, and the eastern margin is a subduction zone. It seems probable that the southern margin of the basin, called the Reed bank crustal block, was formerly attached to mainland Asia. Sometime during the Paleogene the Reed bank crustal block broke away from the continent, and new sea floor was created between the southeastward migrating block and the Asian mainland. Old ocean crust in front of the advancing block was subducted along the northwestern sides of Borneo and Palawan. Subduction ceased in the early Miocene with the collision of the crustal block and the Borneo-Palawan isthmian ridge.

  3. South China connected to north India in Gondwana: sedimentary basin and detrital provenance analyses

    Science.gov (United States)

    Yao, W.; Li, Z. X.; Li, W. X.; Li, X. H.; Yang, J. H.

    2015-12-01

    The paleoposition of South China during the Ediacaran-Silurian is important for understanding the assembly of Gondwana. We report here the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua foreland basin in South China, and discuss South China's connection with Gondwana and potential tectonic triggers for both the Wuyi-Yunkai orogeny in South China and the Bhimphedian orogeny in north India. The Nanhua basin was involved in a three-stage evolution, which are: Stage 1 (the Ediacaran-Cambrian) recording the start of tectonic subsidence with turbiditic marine clastic deposition, fed by exotic orogens outboard South China; Stage 2 (the Ordovician to earliest-Silurian) featured by migrating depocentres with dominant shallow marine to deltaic clastic deposition, fed by the local Wuyi-Yunkai orogen; and Stage 3 (the Silurian) showing the arrival of depocentre in the Yangtze Block during the waning stage of the Wuyi-Yunkai orogeny with deltaic deposition in the remanent foreland basin. Detrital zircon analyses of the Ediacaran-Silurian sandstones across the Nanhua basin reveal a prominent age population of 1100-900 Ma (with a peak age at ~980 Ma) and moderate populations of Archean-Paleozoic ages, grossly matching that of crystalline and sedimentary rocks in northern India. Zircon isotopes of the Stage 1 samples suggest three Precambrian episodes of juvenile crustal growth at 3.0 Ga, 2.5 Ga and 1.0 Ga, and a major crustal reworking at 580-500 Ma for the source areas, which are constraint to be northwestern India and its surrounding orogens. Together with other evidence, we propose that South China likely collided with northwestern India during the Gondwana assembly, generated the Bhimphedian orogeny in north India and formed two foreland basins on both the north India and South China sides. Far-field stress of the collision triggered the Ordovician-Silurian Wuyi-Yunkai orogeny in South China. The Stage 2-3 samples in the Nanhua basin of South China were shed

  4. Tectonostratigraphic history of the Ediacaran-Silurian Nanhua foreland basin in South China

    Science.gov (United States)

    Yao, Wei-Hua; Li, Zheng-Xiang

    2016-04-01

    This paper presents the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua Basin in South China and explores the relationship between clastic sedimentation in the basin and evolution of the adjacent Wuyi-Yunkai orogen. Sedimentary facies in the basin comprises, in an ascending order, turbiditic marine, shallow marine, and fluvial-dominated deltaic facies, featuring a lateral migration from southeast to northwest. We interpret the Ediacaran-Silurian Nanhua Basin as a foreland basin with a three-stage evolution history. Stage 1: the Ediacaran-Cambrian stage, recording the start of tectonic subsidence with turbiditic marine siliciclastic deposition, fed by exotic orogens outboard South China; Stage 2: the Ordovician to earliest-Silurian stage, characterized by a migrating depocenter with dominant shallow marine and deltaic siliciclastic deposition, fed by the local and northwestward propagating Wuyi-Yunkai orogen; Stage 3: the Silurian stage, showing the arrival of depocenter in the Yangtze Block during the waning stage of the orogeny with deltaic deposition in the remanent foreland basin. The Wuyi-Yunkai orogen remained the dominant sedimentary source region during Stage 3. Stage 1 was likely related to the collision of the South China Block toward northern India during the assembly of Gondwana, whereas Stages 2 and 3 recorded sedimentation during the northwestward propagation and subsequent orogenic root delamination/collapse of the Wuyi-Yunkai orogen, respectively. The Wuyi-Yunkai orogeny in South China is interpreted to have resulted from the far-field stress of the collision between South China and Indian Gondwana.

  5. Detrital provenance of Early Mesozoic basins in the Jiangnan domain, South China: Paleogeographic and geodynamic implications

    Science.gov (United States)

    Xu, Xianbing; Tang, Shuai; Lin, Shoufa

    2016-04-01

    Detrital provenance analysis is an effective way to understand paleogeographic change and geodynamics. In this paper, we present petrological, whole-rock geochemical and detrital zircon U-Pb geochronological analysis of Early and Middle Jurassic terrestrial clastic rocks in the Jingdezhen Basin and the Huangshan Basin in the Jiangnan domain, South China. Petrology and whole-rock geochemistry show that the source rocks are dominated by intermediate to acid component. The Chemical Index of Alteration ranges from 69 to 86, suggesting a moderate weathering history for the source rocks. The Early-Middle Jurassic sediments in the Jingdezhen and Huangshan basins were mostly sourced from magmatogenic greywackes and felsic magmatic rocks, respectively. Detrital zircons have seven age peaks at ~ 240 Ma, ~ 430 Ma, ~ 1390 Ma, ~ 1880 Ma, ~ 2500 Ma, -3200 Ma and 788-999 Ma (a wide peak). Provenance analysis indicates that the source rocks are in the Jiangnan domain, the Northwest Zhejiang Basin and the Wuyishan domain. Combining these with previous results and paleocurrent directions, we infer that the NE-trending Wuyishan and Xuefengshan domains and the nearly E-W-Jiangnan domain and Nanling tectonic belt were orogenic uplifts and watersheds during the Late Triassic to Middle Jurassic. The Early Mesozoic geodynamics in the South China Block was related to the westward subduction of the Paleo-Pacific Plate and the northward continent-continent collision following the closure of the Paleo-Tethys Ocean.

  6. Exploration of drought evolution using numerical simulations over the Xijiang (West River) basin in South China

    Science.gov (United States)

    Niu, Jun; Chen, Ji; Sun, Liqun

    2015-07-01

    The knowledge of drought evolution characteristics may aid the decision making process in mitigating drought impacts. This study uses a macro-scale hydrological model, Variable Infiltration Capacity (VIC) model, to simulate terrestrial hydrological processes over the Xijiang (West River) basin in South China. Three drought indices, namely standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture anomaly index (SMAI), are employed to examine the spatio-temporal and evolution features of drought events. SPI, SRI and SMAI represent meteorological drought, hydrological drought and agricultural drought, respectively. The results reveal that the drought severity depicted by SPI and SRI is similar with increasing timescales; SRI is close to that of SPI in the wet season for the Liu River basin as the high-frequency precipitation is conserved more by runoff; the time lags appear between SPI and SRI due to the delay response of runoff to precipitation variability for the You River basin. The case study in 2010 spring drought further shows that the spatio-temporal evolutions are modulated by the basin-scale topography. There is more consistency between meteorological and hydrological droughts for the fan-like basin with a converged river network. For the west area of the Xijiang basin with the high elevation, the hydrological drought severity is less than meteorological drought during the developing stage. The recovery of hydrological and agricultural droughts is slower than that of meteorological drought for basins with a longer mainstream.

  7. Recognition of relict Mesozoic Dongsha Basin in the northern margin, South China Sea and its implication

    Science.gov (United States)

    Yan, Pin; Wang, Yanlin

    2015-04-01

    The Pearl River Mouth Basin (PRMB) is dominated by NE-trending rift architecture produced mainly during Cenozoic Era. It comprises a series of grabens built up with thick Paleogene and thick Neogene sediments, up to 12000 m, and dividing basement highs composing Yanshanian granitic rocks. Though previously considered as one constituent part of PRMB in the southeast, Dongsha Basin displays major differences in sedimentary architecture and tectonic framework. Firstly, Dongsha Basin is characterized by a prominent angular unconformity, interpreted as a spectacular planation or rough erosion surface which separates the sediment column into two distinct parts. It is interpreted with accumulating seismic and drill data that the underlying strata comprise Early Cretaceous terrestrial, Jurassic marine and possibly Triassic sedimentary rocks totaling to 4~9 km thick, whereas the overlying strata are very thin (usually 0.5~1 km in whole) composing mainly Neogene sediments. The major sedimentary hiatus between them corresponds to the Late Cretaceous to mid-Miocene Epoch, well during the rifting to spreading process when the PRMB developed. Secondly, unlike the PRMB, the Dongsha Basin has suffered considerably less extension except its boundary areas, and actually remained as a relatively stable block though Cenozoic Era. Moreover, there are a few compressive open fold structures within the buried Mesozoic strata over the central Dongsha Basin. These folds trend in NNE and are characterized mostly by few minor growing upthrust faults with offsets in the order of few tens to hundreds meter. The upthrust faults dipped mostly southeastward against the northwestward subduction of paleo-Pacific plate as postulated in other previous study. The blind folds featured more like back-thrust growth tectonics, formed a broad NNE-SSW trending belt, obviously oblique to the trend of northern margin of the South China Sea and the PRMB as well. In a few recent models, the most prominent

  8. Eddy-entrained Pearl River plume into the oligotrophic basin of the South China Sea

    Science.gov (United States)

    He, Xianqiang; Xu, Dongfeng; Bai, Yan; Pan, Delu; Chen, Chen-Tung Arthur; Chen, Xiaoyan; Gong, Fang

    2016-08-01

    The South China Sea (SCS) is the world's largest tropical marginal sea with an oligotrophic basin. In June 2015, a rare large phytoplankton bloom, which is ~500 km long, 100 km wide and lasting more than 19 days, was captured in the northern SCS basin by satellite daily chlorophyll images. Water within the bloom area had a feature of low salinity and high temperature measured by an accidental-passing cruise. Meanwhile, satellite sea level anomaly images and drifter trajectory proved there was a cyclonic eddy nearby. No typhoon and heavy rain happened in this period, so we believed the bloom was triggered by the injection of nutrient-rich Pearl River plume driven by eddy. This is the first report on eddy-entrained Pearl River plume into the SCS, which would raise a new view on irregular transportation of nutrient and carbon and its related biogeochemical influence on the oligotrophic ocean.

  9. Hydrological long-term dry and wet periods in the Xijiang River basin, South China

    Directory of Open Access Journals (Sweden)

    T. Fischer

    2013-01-01

    Full Text Available In this study, hydrological long-term dry and wet periods are analyzed for the Xijiang River basin in South China. Daily precipitation data of 118 stations and data on daily discharge at Gaoyao hydrological station at the mouth of the Xijiang River for the period 1961–2007 are used. At a 24-month timescale, the standardized precipitation index (SPI-24 for the six sub-basins of the Xijiang River and the standardized discharge index (SDI-24 for Gaoyao station are applied. The monthly values of the SPI-24 averaged for the Xijiang River basin correlate highly with the monthly values of the SDI-24. Distinct long-term dry and wet sequences can be detected.

    The principal component analysis is applied and shows spatial disparities in dry and wet periods for the six sub-basins. The correlation between the SPI-24 of the six sub-basins and the first principal component score shows that 67% of the variability within the sub-basins can be explained by dry and wet periods in the east of the Xijiang River basin. The spatial dipole conditions (second and third principal component explain spatiotemporal disparities in the variability of dry and wet periods. All sub-basins contribute to hydrological dry periods, while mainly the northeastern sub-basins cause wet periods in the Xijiang River. We can also conclude that long-term dry events are larger in spatial extent and cover all sub-basins while long-term wet events are regional phenomena.

    A spectral analysis is applied for the SPI-24 and the SDI-24. The results show significant peaks in periodicities of 11–14.7 yr, 2.8 yr, 3.4–3.7 yr, and 6.3–7.3 yr. The same periodic cycles can be found in the SPI-24 of the six sub-basins but with some variability in the mean magnitude. A wavelet analysis shows that significant periodicities have been stable over time since the 1980s. Extrapolations of the reconstructed SPI-24 and SDI-24 represent the continuation of observed significant periodicities

  10. Tectonic Subsidence Analysis of the Pearl River Mouth Basin, Northern South China Sea

    Science.gov (United States)

    Tang, X.; Huang, S. S. X. E. C.; Zhuang, W.; LIU, Z.; Duan, W.; Hu, S.

    2015-12-01

    The Pearl River Mouth Basin (PRMB hereafter) in the northern margin of the South China Sea has attracted great attention not only because of its special tectonic location but also for its abundant hydrocarbon resources. Tectonic evolution controls the petroleum geological condition of hydrocarbon-bearing basins. Efforts have been made to understand the tectonic evolution of this basin. However, many issues about the tectonic features and the evolution process of this basin, such as the age of the breakup unconformities and the anomalously accelerated subsidence during the post-rifting stage, remain controversial. Here we employ tectonic subsidence analysis of sedimentary basins, a technique of removing isostatic loading and compaction effects by back-stripping, to investigate the tectonic controls on the basin formation of the PRMB. We performed the analysis on 4 drill wells and 43 synthetic wells constructed based on recently acquired seismic profiles. The result shows that tectonic subsidence in the eastern sags of the PRMB began to decrease at ~30Ma while in the western sags the onset was ~23.8Ma. This suggests that the break-up time i.e. the end of rifting in the PRMB is earlier in the eastern sags than in the western sags. Abnormally accelerated tectonic subsidence occurred between 17.5-16.4Ma during the post-rifting stage, at an average subsidence rate as high as 301.9m/Ma. This phenomenon discriminates the PRMB from the category of classical Atlantic passive continental marginal basins, of which the tectonic subsidence during the post-rifting stage decays exponentially. The main objective of this paper is to provide insights into the geological and geodynamic evolution of the PRMB. The result bears significance to hydrocarbon exploration in this region.

  11. A continental slope stability evaluation in the Zhujiang River Mouth Basin in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; WANG Jianhua

    2014-01-01

    In nature, a slope stability is determined by the ratio of a sliding resistance to a slide force. The slide force of a marine deep-water continental slope is mainly affected by sediment mechanics properties, a topography, and a marine seismic. However, the sliding resistance is mainly affected by sedimentary patterns and a sedi-mentary stress history. Both of these are different from case to case, and their impact can be addressed when the data are organized in a geographic information system (GIS). The study area on the continental slope in Zhujiang River Mouth Basin in South China Sea provides an excellent opportunity to apply GIS spatial analysis technology for the evaluation of the slope stability. In this area, a continental slope topography and a three-dimension (3-D) topography mapping show a sea-floor morphology and the distribution of a slope steepness in good detail, and the sediment analysis of seabed samples and an indoor appraisal reveals the variability of a sediment density near the sea-floor surface. On the basis of the results of nine geotechnical studies of submarine study areas, it has worked out that an equivalent cyclic shear stress ratio is roughly between 0.158 and 0.933, which is mainly depending on the initial water content of sediment. A regional density, slope and level of anticipated seismic shaking information are combined in a GIS framework to yield a map that illustrates a continental slope stability zoning under the influencing factors in Zhujiang River Mouth Basin in the South China Sea. The continental slope stability evaluation can contribute to north resources development in the South China Sea, the marine functional zoning, the marine engineering con-struction and adjust measures to local conditions, at the same time also can provide references for other deep-water slope stability analysis.

  12. Teleconnection analysis of runoff and soil moisture over the Pearl River basin in South China

    Directory of Open Access Journals (Sweden)

    J. Niu

    2013-09-01

    Full Text Available This study explores the teleconnection of two climatic patterns, namely the El Niño-Southern Oscillation (ENSO and the Indian Ocean Dipole (IOD, with hydrological processes over the Pearl River basin in South China. The Variable Infiltration Capacity (VIC model is used to simulate the daily hydrological processes over the basin for the study period 1952–2000, and then, using the simulation results, the time series of the monthly runoff and soil moisture anomalies for its ten sub-basins are aggregated. Wavelet analysis is performed to explore the variability properties of these time series at 49 timescales ranging from 2 months to 9 yr. Use of wavelet coherence and rank correlation method reveals that the dominant variabilities of the time series of runoff and soil moisture are basically correlated with IOD. The influences of ENSO on the terrestrial hydrological processes are mainly found in the eastern sub-basins. The teleconnections between climatic patterns and hydrological variability also serve as a reference basis for inferences on the occurrence of extreme hydrological events (e.g. floods and droughts.

  13. Relationship between Formation of Zhongyebei Basin and Spreading of Southwest Subbasin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    Gao Hongfang; Zhou Di; Qiu Yan

    2009-01-01

    The Zhongyebei (中业北) basin (ZYBB) is an NE-striking,narrow and small sedimentary basin superimposing the southern 1/2 segment of the proposed spreading axes of the SW subbasin of the South China Sea (SCS).More than 4 500 m strata were identified in the Zhongyebei basin,including the Paleogene lower structure layer and the Neogene upper structure layer.The SW subbasin of the South China Sea has been regarded as an oceanic basin opened by seafloor spreading,as evidenced by the fiat and deep (> 4 000 m mostly) seafloor with linear magnetic anomalies,and by the shallow Moho depth of < 12 km as estimated from gravity modeling.The classic model of seafloor spreading predicts that sediments on the oceanic crust are younger and thinner towards the spreading axes.But in the southwestern segment of the SW subbasin,contradictions appear.Firstly,the thick sedimentation in the ZYBB is along the proposed spreading axes.Secondly,the sediments are thinner (500-1 500 m) and younger away from the proposed spreading axes.Thirdly,geological elements of the two sides of spreading axes develop asymmetrically in the southwestern SW subbasin.Two models,the early opening model and the limited modeling model,are suggested for resolving this paradox.The former suggests that the opening of the SW subbasin was in Late Eocene and earlier than the oldest sediment in the ZYBB.The latter proposes that the opening of the SW subbasin was limited to its northeastern portion,and did not extend to the southwest portion.The ZYBB is a rift basin survived from the spreading but subjected to severe syn-spreading magmatic disturbance.The SW subbasin and the ZYBB of the SCS provide a unique opportunity for studying the structural evolution and dynamic mechanism at the tip of a propagating seafloor spreading.Both models have unresolved questions,and further studies are needed.

  14. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from analogue modelling

    Science.gov (United States)

    Ding, Weiwei; Li, Jiabiao

    2016-10-01

    How the South China Sea rifted has long been a puzzling question that is still debated, particularly with reference to the Southwest Sub-basin (SWSB). Analogue modelling remains one of the most useful tools for testing rift models and processes. Here, we present and discuss a series of analogue modelling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical results were compiled to provide realistic constraints to test the experimental results and interpretations. A heterogeneous lithosphere model with a varied lithospheric structure showed tectono-morphological features similar to the natural case of the SWSB, indicating that the initial thermal condition and rheological stratification of the lithosphere should have a dominant effect on the rifting process of the SWSB. Rigid tectonic blocks existed in the continental margin, such as the Macclesfield Bank and the Reed Bank, and they played important roles in both the shaping of the continent-ocean boundary and the coupling between the crust and mantle. The initial thermal condition and rheological stratification of the lithosphere under the South China Sea controlled the propagated rifting process of the SWSB. Extension was centred on the deep troughs between the rigid blocks, and the break-up occurred in these areas between them. The westward rifting propagation is best explained with a heterogeneous lithosphere model characterized by varied lithospheric structure, and it was responsible for producing the V-shaped configuration of the SWSB.

  15. Development of a model-based flood emergency management system in Yujiang River Basin, South China

    Science.gov (United States)

    Zeng, Yong; Cai, Yanpeng; Jia, Peng; Mao, Jiansu

    2014-06-01

    Flooding is the most frequent disaster in China. It affects people's lives and properties, causing considerable economic loss. Flood forecast and operation of reservoirs are important in flood emergency management. Although great progress has been achieved in flood forecast and reservoir operation through using computer, network technology, and geographic information system technology in China, the prediction accuracy of models are not satisfactory due to the unavailability of real-time monitoring data. Also, real-time flood control scenario analysis is not effective in many regions and can seldom provide online decision support function. In this research, a decision support system for real-time flood forecasting in Yujiang River Basin, South China (DSS-YRB) is introduced in this paper. This system is based on hydrological and hydraulic mathematical models. The conceptual framework and detailed components of the proposed DSS-YRB is illustrated, which employs real-time rainfall data conversion, model-driven hydrologic forecasting, model calibration, data assimilation methods, and reservoir operational scenario analysis. Multi-tiered architecture offers great flexibility, portability, reusability, and reliability. The applied case study results show the development and application of a decision support system for real-time flood forecasting and operation is beneficial for flood control.

  16. Structural style and Basin Formation in Deep-water Area of Northern South China Sea

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    di, Z.; Zhen, S.; Xiong, P.; Min, C. C.

    2007-12-01

    In the deep-water area of northern South China Sea (SCS) developed a series of sedimentary basins. Active exploration for deep-water hydrocarbon has begun in these areas since this century. The well LW3-1-1 at water depth of 1480m in the BaiYun Sag (BYS) of the Pearl River Mouth Basin in 2006 discovered 56m layer of pure gas, demonstrated the good hydrocarbon potential of the area. Wide-angle seismic profiling has verified the transitional type of crust in the slope areas. The Moho surface shoals step-by-step from 30-29km under the shelf, ~15 km under the slope, and ~12km under the abyssal plain. Moho also rises beneath depocenters, mirroring the shape of sedimentary basement. The crustal thickness at the center of the BYS is Pacific Ocean towards the East Eurasian margin. The stress field in the East Eurasian margin changed abruptly in Late Cretaceous. Rifting started in the entire margin and eventually led to the opening of the SCS in late Early Oligocene. Large sedimentary basins developed in the margins of the SCS. Paleogene lacustrine sediments contain hydrocarbon sources, while traps are mostly found in Neogene marine strata. The structure of the northern SCS shows clear W-E variation, divided into NE-, NEE-, and NE-trending segments by two major NW-SE transfer faults. The Southern Depression of the Qiongdongnan Basin to the west is characterized by NE-trending half grabens. The BYS at the central segment is characterized by NEE-trending composite grabens and down warps with relatively small offset of boundary faults. To the east the Chaoshan Depression is composed of Mesozoic strata under very thin (deep-water basins is different from that of shallow-water basins. A study is ongoing to explore the basin formation mechanism, taking into account of the factors of abnormal lithosphere rheology, active mantle underplating and magmatic heating, lower crust flow, as well as the superposition of later extensional events. The study is supported by NSFC grants

  17. Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU ZhiFei; Christophe COLIN; HUANG Wei; CHEN Zhong; Alain TRENTESAUX; CHEN JianFang

    2007-01-01

    Clay minerals have played a significant role in the study of the East Asian monsoon evolution in the South China Sea by being able to track oceanic current variations and to reveal contemporaneous paleoclimatic changes prevailing in continental source areas. As one of the most important rivers inputting terrigenous matters to the northern South China Sea, the Pearl River was not previously paid attention to from the viewpoint of clay mineralogy. This paper presents a detailed study on clay minerals in surface sediments collected from the Pearl River drainage basin (including all three main channels,various branches, and the Lingdingyang in the estuary) by using the X-ray diffraction (XRD) method.The results indicate that the clay mineral assemblage consists dominantly of kaolinite (35%-65%),lesser abundance of chlorite (20%-35%) and illite (12%-42%), and very scare smectite occurrences (generally <5%). Their respective distribution does not present any obvious difference throughout the Pearl River drainage basin. However, downstream the Pearl River to the northern South China Sea, the clay mineral assemblage varies significantly: kaolinite decreases gradually, smectite and illite increase gradually. Additionally, illite chemistry index steps down and illite crystallinity steps up. These variations indicate the contribution of major kaolinite, lesser illite and chlorite, and very scarce smectite to the northern South China Sea from the Pearl River drainage basin. The maximum contribution of clay minerals from the Pearl River is 72% to the northern margin and only 15% to the northern slope of the South China Sea. In both glacials and interglacials, kaolinite indicates that the ability of mechanical erosion occurred in the Pearl River drainage basin.

  18. Occurrence and origin of carbon dioxide in the Fushan Depression, Beibuwan Basin, South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meijun; Wang, Tieguan [Key Laboratory for Hydrocarbon Accumulation Mechanism of the Chinese Ministry of Education, Earth Sciences and Geoinformatics School, China University of Petroleum, Beijing 102200 (China); Liu, Ju; Wu, Weiqiang; Gao, Lihui [Petro China Southern Oil Exploration and Development Company, Guangzhou 510640 (China); Lu, Hong [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2008-06-15

    Natural gases produced from the Fushan Depression, Beibuwan Basin, South China Sea are generally rich in carbon dioxide. The {delta}{sup 13}C values of methane in these gases are within the range of -41.18 permille to -47.00 permille. This, together with the linearity of the {delta}{sup 13}C values of methane to butane in the ''natural gas plots,'' indicates that the hydrocarbon gases are of organic origin. The {delta}{sup 13}C{sub CO2} values of these gases are in the range of -5.1 permille to -7.5 permille, suggesting an inorganic origin. A dominant mantle source for the CO{sub 2} in these gases was determined on the basis of a simple binary mixing model using the {delta}{sup 13}C{sub CO2} values and {sup 3}He/{sup 4}He ratios of associated helium in these gases. The primary geological controls on the occurrence of CO{sub 2} rich gas accumulations in the Fushan Depression are discussed following a comparison with other sedimentary basins in the region. (author)

  19. Observation of Catastrophic Degassing from Mantle-Crust in Yinggehai Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    Chen Honghan; John Parnell; Gong Zaisheng; Li Sitian

    2004-01-01

    To lower the CO2 risk for hydrocarbon exploration in the west continental shelf of Yinggehai basin, South China Sea, we do attempt not only to know the CO2 origins, but also to make an understanding of the degassing processes from the mantle and crust. Based on the stable carbon isotope ratios of CO2 alone, the organic and inorganic CO2 can be successively distinguished, but the formation conditions and mixing processes for inorganic CO2 are still not clear. The relationships between lg[R(=3He/4He)/Ra(=1.386×10-6)] and CO2 content (%), CO2/3He and δ13CCO2 have been employed, respectively, to obtain that the CO2 gases in the reservoirs can be classified into three categories: (1) organic CO2 with very low contents but contaminated by mantle-derived helium; (2) inorganic CO2 gases with lower to higher contents being mixtures of crustal CO2 with mantle-derived CO2, the mantle-contributed percentage being in the range of 0 %-27 %, and (3) mainly crust-derived inorganic CO2 gases being characterized by high contents (more than 50 %) and indicating the crustal addition by metamorphism of rich-in carbon rocks in basement. Nevertheless, some CO2/3He ratios of organic CO2 fall into the range 108-1010, which made us inquire whether the CO2/3He=(1-10)×109 can be the unique signature of magmatic CO2 or not. All the observation of plutonic activities, fluid inclusion measurements in gas reservoirs, pre-stack depth/time seismic sections and the satellite infrared remote photography taken from Yinggehai basin, South China Sea, during Chichi earthquake in Taiwan on September 21, 1999, supports that the degassing processes are in a discontinuous mode, which may be triggered by igneous intrusion or extrusion, or earthquakes. In the central diapir zone of the basin, at least 3 to 4 orders of discharge of across-formational thermal fluid flows through fractures can be determined in different scales. The mantle degassing process may have a strong effect on overpressured system

  20. Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

    OpenAIRE

    Daidai Wu; Nengyou Wu; Ying Ye; Mei Zhang; Lihua Liu; Hongxiang Guan; Xiaorong Cong

    2011-01-01

    Several authigenic minerals were identified by XRD and SEM analyses in shallow sediments from the Southeast Hainan Basin, on the northern slope of South China Sea. These minerals include miscellaneous carbonates, sulphates, and framboidal pyrite, and this mineral assemblage indicates the existence of gas hydrates and a methane seep. The assemblage and fabric features of the minerals are similar to those identified in cold-seep sediments, which are thought to be related to microorganisms foste...

  1. Mixed volcanogenic-lithogenic sources for Permian bauxite deposits in southwestern Youjiang Basin, South China, and their metallogenic significance

    Science.gov (United States)

    Yu, Wenchao; Algeo, Thomas J.; Du, Yuansheng; Zhang, Qilian; Liang, Yuping

    2016-07-01

    Bauxite deposits at the base of the Upper Permian Heshan Formation in the Youjiang Basin, South China, contain zircons with dominant age peaks at 263-262 Ma. During the Middle to Late Permian, the Youjiang Basin consisted of a number of isolated and attached carbonate platforms separated by inter-platform troughs. The bauxite deposits are limited to the isolated carbonate platform facies and are not present on attached carbonate platforms and inter-platform troughs. Discriminant plots based on the trace element composition of the zircons indicate a combination of within-plate/anorogenic and arc-related/orogenic sources. Geochemical and isotopic data suggest that the metallogenic materials of the bauxite deposit came from felsic volcanic rocks of the Emeishan Large Igneous Provence (ELIP) in South China and from the Truong Son volcanic arc located between the South China and Indochina cratons. The northwestern and southeastern parts of the Youjiang Basin received larger amounts of ELIP detritus and volcanic arc detritus, respectively. Coarser siliciclastic material in proximal attached carbonate platform and inter-platform trough settings was delivered by rivers, but finer siliciclastics that accumulated on distally located carbonate platforms in isolated deep-water areas was probably transported by wind.

  2. Salt-related tectonics in the eastern Sichuan Basin, South China

    Science.gov (United States)

    Gu, Zhidong; Yin, Jifeng; Yuan, Miao; Zhai, Xiufen

    2015-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze platform of South China, and East Sichuan is situated between Huaying Mountain fault and Qiyue Mountain fault. The surface Jura type folds are very famous with barrier parallel folds, but the cause of folds formation have not been completely understood. Stratigraphic units are composed of thick competent flexural layers separately by relatively thin incompetent ductile layers that can act as detachments.Multiple detachment layers are developed in the eastern Sichuan and result in distinct structural domains. In addition to the basal, Triassic and Silurian system detachment layers, we recognize a regionally extensive salt layer in the Middle and Lower Cambrian. The recognition of salt layer is by the synthetical studies of outcrop, drilling well, and chaotic seismic reflection configuration. The Middle and Lower Cambrian salt forms a tectonic domain boundary that can be observed by seismic reflection profile in subsurface. The stratigraphic intervals above and below the salt develop characteristic salt-related tectonics. And the folds formation is by flow in and flow out of salt movement of the Middle and Lower Cambrian and flexural slip and grouding of the overlying units. Above the salt, the thrust fault-related folds were generated by the contractional action from southeast to northwest, including the fault-bend fold, fault-propagation fold, and thrust wedge fold, and so on. Below the salt, the broad anticlines were formed due to the basal detachment. Hydrocarbon traps are formed above and below the salt, and they are potential gas exploration domains in the eastern Sichuan Basin.

  3. Stable isotopic studies of dinosaur eggshells from the Nanxiong Basin,South China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Stable carbon and oxygen isotopes have been observed in dinosaur eggshell samples,identified as Macroolithus yaotunensis,collected in two sections of the Nanxiong Basin,Guangdong Province,South China.Multiple positiveδ18O perturbations that occurred during the K/T transition of about 150 ka suggest that there may have been at least three periods of the extreme dry climate with a mean annual air temperature over 27℃.δ13C ranges from -8.37‰ to -11.60‰ of the dinosaur eggshells,added to the metabolic enrichment of 16‰,may indicate that the dinosaurs represented by this type of eggshells probably consumed the plant species of C3 type with the δ13C values of -24.3‰- -27.6‰.Moreover,the trend toward more negative δ13C values of the eggshells during the K/T transition could be an indirect consequence of a lasting increase in atmospheric CO2 concentration.

  4. The distribution of dimethylcarbazoles in oils from the Pearl River Mouth Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chunming; ZHAO Hongjing; GAO Kunshun; YANG Shaokun

    2007-01-01

    C2-carbazole isomers have been investigated in crude oils from the Hui-Liu Structure Ridge (HLSR) in the Pearl River Mouth Basin (PRMB), South China Sea. The NH shielded isomer, as well as the NH partially shielded isomers, was detected in high abundance and the NH exposed isomers in lower abundance. A small-enrichment trend of 1,8-dimethylcarbazole (DMC) was observed in crude oils along the western part of HLSR (WPHLSR), which may indicate little effect of migration on the C2-carbazole distributions. Two strikingly different distribution patterns of NH partially shielded isomers were observed in the reservoirs along the WPHLSR: one with a preference of 1,3- and 1,6-DMCs and the other with a preference of 1,4- and 1,5-DMCs. All of the oils occurring in the Upper reservoirs have a preference of 1,3- and 1,6-DMCs, whereas those trapped in the Lower reservoirs show a preference of 1,4- and 1,5-DMCs, which may indicate there are two petroleum migration systems in the WPHLSR.

  5. The Paleo-Orientations of Northwestern Borneo and Adjacent South China Sea Basins

    Directory of Open Access Journals (Sweden)

    H. D. Tjia

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i2.136Limited paleomagnetic data from West Kalimantan and southwestern Sarawak appear to indicate counter-clockwise (CCW rotation of over 50 degrees during Cenozoic. On the other hand, similar studies from Sabah show conflicting results in terms of paleo-positions. This CCW information and other plate tectonic considerations have formed the base of Southeast Asia’s plate reconstructions that have seen print in a number of updated versions. The existing publications on extensive field and exploration data, including geological stress fields from wellbore breakouts, on northwestern Borneo and basins of South China Sea have not been taken into account. The latter wealth of information already established that the region under discussion consists of a mosaic-like assemblage of diverse tectono-stratigraphic terranes, each with separate tectonic development. Stress fields changed in different ways in the different terranes indicating definitively that regional, progressive CCW rotation of Borneo is not possible.

  6. Lithology, kinematics and geochronology related to Late Mesozoic basin-mountain evolution in the Nanxiong-Zhuguang area, South China

    Institute of Scientific and Technical Information of China (English)

    SHU; Liangshu; DENG; Ping; WANG; Bin; TAN; Zhengzhong; YU

    2004-01-01

    The Nanxiong red-bed basin and its adjacent Zhuguang granite form a distinctive basin-mountain landform in the Nanling region, South China. Research results suggest that the Zhuguang granite is a polyphase composite pluton developed on the metamorphic basement of the paleo-Tethys-paleo-Asian tectonic regime and possesses geometrical and kinematic features of hot-doming extensional tectonics at the middle-upper crustal level, which is considered as a magmatic complex that resulted from the collision-orogeny during the Indosinian Period, the subduction-consuming during the Early Yanshanian Period and the intra-continental basaltic underplating and deep-seated geodynamics during the Late Yanshanian Period. The Nanxiong basin is a Late Cretaceous-Paleogene asymmetric faulted basin that is characterized by a fault boundary on the northern side and an uncomformable boundary on the southern side, its deposit center was migrated gradually from south to north. Structural kinematic results on the basin-mountain coupled zone demonstrate that the ductile and the brittle rheological layers show a quite coincident sense of shear, implying that it is a continuous process from the ductile extensional deformation followed by locally sinistral strike-slip shear at a middle-crustal level to the brittle tensional deformation at a upper-crustal level during formation of granitic doming extensional tectonics. The Zhuguang granite and the Nanxiong faulted basin constructed a semi-graben tectonic system. Lithological and geochemical results suggest that the Late Triassic to Jurassic granitic bodies in the Zhuguang have some similar features: high SiO2, Al2O3, K2O contents, alkalinity index > 2.8, ANKC value > 1.1, LREE-enriched pattern with high REE contents, marked negative Eu anomalies, enrichment in Rb and Th, depletion in Ba and Nb, showing a K-rich and Al-rich calc-alkaline affinity, which suggest a continuous magmatic evolution from Late Triassic to Jurassic. Formation of

  7. Crustal Structure and Extension from Slope to Deepsea Basin in the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Hu Dengke; Zhou Di; Wu Xiangjie; He Min; Pang Xiong; Wang Yuwei

    2009-01-01

    The newly acquired long-cable multi-channel seismic (MCS) lines were used to study the crustal structure and extension in an NW-SE elongated 150 km by 260 Van strip from the slope to the deepsea basin in the northern South China Sea (SCS).These profdes are of good penetration that Moho is recognizable in ~70% length of the lines.Seismostrattgraphic interpretation and time-depth conversion were conducted.A power function D = atb+ c was used in the time-depth conversion,which avoided the under-or over-estimation of the depths of deep-seated interfaces by cubic or quadratic polynomial functions.Contour maps of basement depth,Moho depth,crustal thickness,and crustal stretching factor were obtained for the study area.In the dip direction,the Moho depth decreases stepwisely from 28 km in the outer shelf southwards to 19,15,and 12 km in the deepsea basin,with ramps at the shelf break,lower slope,and the continent ocean boundary (COB),respectively.Accordingly,the crustal thickness decreased southwards from 3,and 7 km spectively.Under the center of the Balynn (白云) sag,the crust thins significantly to < 7 kin.The crustal stretching factor βc was calculated by assuming the original crust thickness of 30 km.In the centers of the Baiyun sag,βc exceeds 5.Tertiary and Quaternary volcanic activities show a general trend of intensifying towards the COB.An important finding of this study is the along-strike variation of the crustal structure.A Moho rise extends from the COB NW-ward until the shelf break,about 170 km long and 50-100 km wide,with Moho depth < 20 kin.This is called the Balyun Moho Nose,which is bounded to the east,west,and north by belts of high Moho gradients indicative of crustal or even lithospheric faults.The doming of Moho in the nose area might he the cause of the W-E segmentation of the crustal and geological structures along the slope of the northern South China Sea,and the cause of the strong crustal

  8. A geochemical investigation of crude oils from Eastern Pearl River Mouth Basin, South China Sea

    Science.gov (United States)

    Jiamo, Fu; Cunmin, Pei; Guoying, Sheng; Dehan, Liu; Sizhong, Chen

    A thorough petroleum exploration of the Pearl River Mouth Basin (PRMB), South China Sea, began in 1983. At present, several oilfields have been found in the PRMB, mainly distributed in Dongsha Massif, Huizhou and Xijiang Depressions as well as Huilu Lowhigh, and one of them has been developed recently. The crude oils found in the basin can be classified into two types. One is normal waxy type, and the other is cyclic type, which may be caused by minor biodegration and is restricted to the Liuhua District of Dongsha Massif. However, on the basis of geochemical characteristics, all the crude oils are thermally mature, indicating that they are derived from source rocks which have entered the main oil generation period but their maturity is not high enough to reach the overmature stage. Moreover, in the biomarker distribution, the oils also share many similarities. Almost all the oils contain abundant C 30 4-methylsteranes with 24-ethyl side chain, ubiquitous oleanane and lower concentration of gammacerane, and possess high ratios of Ni/V, pristane to phytane and C 30 hopane over total C 29 steranes as well as high paraffin wax and low sulphur content, indicating that they originated from terrestrial organic matter deposited in lacustrine and marsh coal-forming environments. However, some characteristics resemble Brazilian offshore oils of salinewater lacustrine environment. The oils found in the PRMB can also be classified into three main genetic types based on the relative values of pristane over phytane ratio, C 29 sterane preference and the composition of the carbon isotope. Type I oils occurred in the Huizhou and the Xijiang Depressions and their adjacent Dongsha Massif. It has higher ratios of pristane to phytane (1.80-5.54 and 3.21 on the average scale) and heavier carbon isotopic composition, indicating that their source rocks contain much more abundant terrestrial higher plant input. Type II, encountered in Huilu Lowhigh and its bounding area of Dongsha Massif

  9. Moho structure of the South China Sea basin and the surrounding from constrained 3-D gravity inversion

    Science.gov (United States)

    Zhaocai, W.; Jinyao, G.

    2014-12-01

    We have obtained the Moho depth of the South China Sea basin using gravity data with the 191 control points from seismic data and sonobuoys. To obtain the residual mantle Bouguer anomaly (RMBA), we deducted the anomaly from lateral changes in bathymetry or topography, the gravity anomaly due to changes in sediment thickness and density from the free air anomaly firstly, and then corrected the lithosphere thermal gravity anomaly from the rifted margin to the spread ridge. According to the relationship between the control points and RMBA, we calculated the initial Moho depth, from which, we done an iterative cycle of gravity inversion to predict the final Moho depth and crustal thickness. To calculate the lithosphere thermal gravity anomaly, we defined a critical thinning factor for the initiation of oceanic crust production, and a maximum oceanic crustal thickness; for this study area, values of 0.5 and 9 km were used respectively, consistent with the Moho depth of 20km and 14km respectively, with the initial thickness of continental crust of 32km. The RMS(root mean square) difference with the control points is 1.54km. Over most of the South China Sea basin, the Moho depth is 11 and 13km, the crustal thickness is 5-8km. The Moho depth of the Northwest sub basin has values between 12 and 13km, the crustal thickness is mostly ~7km. The NW trending fault divides obviously the extinct spreading centers of the East and southwest sub basin. Meanwhile, on the north side of the two sub basin extinct spreading centers, the crustal thickness is slightly thicker 1km than the south. The ocean-continent transition (OCT) is enclosed by the 14km and 20km Moho depth contour. At the East sub basin, the OCT shows asymmetry, and is broader and longer on the northern margin than the southern margin. One of the most noticeable characteristics in the northeastern margin of the OCT is that the crustal thickness is 10-16km. However, at the southwest sub basin, the OCT is symmetrical.

  10. Characteristics of hydrothermal sedimentation process in the Yanchang Formation, south Ordos Basin, China: Evidence from element geochemistry

    Science.gov (United States)

    He, Cong; Ji, Liming; Wu, Yuandong; Su, Ao; Zhang, Mingzhen

    2016-11-01

    Hydrothermal sedimentation occurred in the Triassic Yanchang Formation, Ordos Basin, China. However, their macroscopic features at the scale of the stratum and hydrothermal sources still lack correlational research. This paper performed element geochemical study on a large number of core samples collected from the Yanchang Formation of a new drilling well located in the south Ordos Basin. The SiO2/(K2O + Na2O) vs. MnO/TiO2 crossplot and Fe vs. Mn vs. (Cu + Co + Ni) × 10 ternary diagram demonstrate that the Yanchang stratum in the study area has, in general, hydrothermal components. The Al/(Al + Fe + Mn) and (Fe + Mn)/Ti ratios of the core samples range from 0.34 to 0.84 and 4.81 to 50.54, averaging 0.66 and 10.67, respectively, indicating that the stratum is a set of atypical hydrothermal sedimentation with much terrigenous input. Data analysis shows that the hydrothermal source in the study area was from the deep North Qinling Orogen around the south margin of the basin, where some active tectonic and volcanic activities took place, rather than from the relatively stable internal basin. Early Indosinian movement and volcanic activities activated basement faults around the southern margin of the basin, providing vents for the deep hydrothermal fluid upwelling. The hydrothermal indicators suggest that the study area experienced 4 episodes of relatively stronger hydrothermal activity, namely during the Chang 10, Chang 9-1, Chang 7-3 and Chang 6-2 periods. We also propose a new hydrothermal sedimentation model of hydrothermal fluids overflowing from basin margin faults, for the Yanchang Formation, which is reported here for the first time.

  11. The geochemistry characteristic and dating of cold seepage carbonates of the Pearl River Mouth Basin, eastern of South China Sea

    Science.gov (United States)

    Fang, Yunxin; Fu, Shaoying

    2015-04-01

    Cold seepage carbonates are usually formed by the interaction of methane oxidizing archaea, sulfate reducing bacteria and cold seepage which contain abundant venting hydrocarbon gases. The presence of cold seepage carbonates on the seabed is one of the evidences that the area exist venting hydrocarbon gases, which are usually result by the dissociation of gas hydrate. The cold seepage property and fluid flow rate can influence the oxidation-deoxidation environment of the bottom water and sediment. Many previous studies focused on the mineral composition, microstructure, elemental composition, isotope composition of the cold seepage carbonates and isotopic dating for the cold seepage carbonates. The isotopic dating for the cold seepage carbonates can provide the information of the gas hydrate formation and dissociation in some area of the South China Sea. High precision TIMS-U dating and 14C dating are used as routine method for the dating of the Quaternary carbonates and fossils. The cold seepage carbonates in the study include the samples collected by ROV on the seabed and the drilling for gas hydrate in the Pearl River Mouth Basin, eastern of the South China Sea. The authigenic carbonate occurred in different depth in the A, B and C drilling site. They may be represent different events of gas hydrate formation and dissociation in the Quaternary. The dating study for all the cold seepage carbonates can provide the relative accurate eras of the gas hydrate dissociation events in certain area of the South China Sea.

  12. Vertical Migration of Petroleum via Faults in Zhu Ⅲ Subbasin, Pearl River Mouth Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The problem that faults act as a conduit for hydrocarbon-bearing fluid flow has been under debate for a long time. The southern boundary fault (FS) and No.2 fault belt in the Zhu Ⅲ subbasin in the Pearl River Mouth basin (PRMB) of South China Sea (SCS) are considered as the conduit of hydrocarbons for the oil and gas fields in the hydrocarbon-generating half grabens. Based upon the basin modeling and seismic velocity inversion simulation, there are abnormal-pressure compartments in the central part of half grabens. Wenchang, Enping and Zhuhai FormationⅡare seated within the abnormal-pressure zone, while the Zhuhai Formation Ⅰ is within the pressure-transition zone. The abnormal pressure was mainly caused by undercompaction due to the high rate of sedimentation for layers with an abnormal pressure. The increase of temperature of inclusions as the increase of depth supports vertical migration via faults in the study area.

  13. Evidence for episodic expulsion of hot fluids along faults near diapiric structures of the Yinggehai Basin, South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Xinong Xie; Sitian Li [China University of Geosciences, Wuhan (China). College of Earth Resources; Weiliang Dong; Zhongliang Hu [China Offshore Oil Nanhai West Corp., Zhanjiang (China)

    2001-06-01

    Diapiric structures are well developed and occur in most of the central part of the Yinggehai Basin, on the western side of the South China margin. A strong thermal anomaly due to hot fluid flows occurs in the diapiric zone, as evidenced from vitrinite reflectance (R{sub o}), clay mineral transformation, and fluid inclusion homogenization temperatures. This anomaly results from hydrothermal fluid flow along vertical faults from overpressured compartments into the overlying Late Miocene and Quaternary sand-rich layers. The magnitude of thermal anomaly is related not only to the distance to which the vertical fault is hydraulically open, but the permeability of rocks interconnected with the faults. Intense heat transfer for convection of fluids occurs in the sand-rich intervals adjacent to vertical faults. Abnormal organic-matter maturation, together with rapid transformation of clay minerals, which occurs at certain intervals within the present-day normally pressured system and normal conductive temperatures in a diapir, can be used to identify palaeo high pressure zones. Abnormal high temperatures measured from a drill-stem test in a diapir can be inferred to be the results of recent expulsion of hydrothermal fluid flow. The results of this study suggest that thermal fluid expulsion along faults plays an important role in the modification of thermal regimes, the enhancement of organic-matter maturation, and rapid transformation of clay minerals, as well as the accumulation of hydrocarbons in diapiric structures of the Yinggehai Basin, South China Sea. (author)

  14. Composition and Origin of Shallow Biogenetic Gases in the Baise Basin, South China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the analytical data of over 30 gas samples, combined with geochemical and geological backgrounds, the composition and distribution characteristics of shallow biogenetic gases in the Baise Basin, a Tertiary residual basin in southern China, were extensively investigated, and the origin and formation mechanism tentatively approached. The shallow gases are primarily composed of gaseous hydrocarbons, generally accounting for over 90%. The abundances of methane and C2+homologues show a relatively wide range of variation, mainly 50%-100% and 0%-50%, respectively,depending on the mixing proportions between biogenetic and thermogenic gases. A highly negative carbon isotope is the significant signature for the shallow gases with δ13C1 values of -55‰ to -75‰.According to molecular and isotopic compositions and light hydrocarbon parameters, the shallow gases in the basin can be classified into three types of origins: biogenetic gas, biogenetic/thermogenic mixed gas, and oil-biodegraded gas. They exhibit regular distribution both spatially and temporally, and are believed to be associated with the maturity of adjoining gas source rocks and biodegraded oil accumulation. The Baigang and Nadu source rocks can be considered to have experienced early and late gas generation during early burial and after basin uplift respectively. A late accumulation mechanism of multiple gas sources is put forward for the formation of the shallow gas reservoirs, which is responsible for the variations in chemical and isotopic composition of the gases in depth profile.

  15. Evolution of deepwater sedimentary environments and its implication for hydrocarbon exploration in Qiongdongnan Basin, northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; JIANG Tao; ZHANG Daojun; WANG Yahui; ZUO Qianmei; HE Weijun

    2015-01-01

    Over the past several years, a number of hydrocarbon reservoirs have been discovered in the deepwater area of Qiongdongnan Basin, northwestern South China Sea. These oil/gas fields demonstrate that the evolution of the deepwater sedimentary environment are controlling the formation and distribution of large-scale clastic reservoirs. Integration between seismic and borehole data were necessary to best clarify the distribution and quality of these deepwater reservoirs. Geochemical and paleobiological evidence from discrete samples was also applied to document specific information regarding the sedimentary environment. Results show that the Qiongdongnan Basin has existed as a thriving marine environment since Oligocene, when several rifting depressions developed throughout the entire Qiongdongnan Basin. Triggered by the faults activities, several distinct provenances supplied the coarse sediments, transporting and depositing them in deep parts of the rifting depressions. A fan delta system then formed nearby the source in the deeper area of these rifting depressions. The sedimentary environment of Qiongdongnan gradiationally became deepwater since early Miocene. Consequently, abundances of sediments were transported from Hainan Island and Southern Uplift, and then sunk into the basin center. The submarine fans revealed by many boreholes in this area verified them as good reservoir. Because the area reached its lowest sea level at late Miocene and the Southern Uplift subsidenced under sea level, not providing any sediment, so that the carbonate mesa and biorhythms characteristic of this area also developed during this period. In the west part of Qiongdongnan Basin, sediments transported from Vietnam increased in response to the Tibetan Uplift. Consequently, a central canyon developed along the center of Qiongdongnan Basin, which has been confirmed by several boreholes as a favorable hydrocarbon reservoir. The clarification of the deepwater sedimentary environment

  16. BASIN DYNAMICS AND BASIN GROUPS OF THE SOUTH CHINA SEA%南海的盆地群与盆地动力学

    Institute of Scientific and Technical Information of China (English)

    李三忠; 安慧婷; 薛友辰; 熊莉娟; 曹现志; 许立青; 索艳慧; 刘鑫; 戴黎明; 余珊; 赵淑娟; 马云; 王霄飞; 程世秀

    2012-01-01

    The South China Sea was formed in Cenozoic. Basins in the South China Sea could be divided into different types, such as continental shelf basins, continental slope basins and deep sea basins, which are closely related with the rifting and transition of the continental margins, and thus could be grouped into strike-slip-related pull-apart and extensional basins, extrusion-escape-related rifting basins, extension- and subduction-related buckling basins. They developed further into some ndge-spreading-related oceanic sub-basins in different stages. These basins were formed not under a single dynamics but under a very complex and changeable dynamics. These basins have suffered from a series of Cenozoic tectonic movements, such as the Shenhu, the South China Sea, the Dongsha, resulting in the formation and spatial-temperal migration of complex angular unconformities in these basins. Accompanying with the tectonic migrations and evolutions in these basins, faulting, magmatism, shifting of sedimentary subsidence centers and depo-centers, oil accumulation and geohazards show a significant feature of jumping. The complex dynamic settings of the South China Sea have caused many controversies on their origin. The plate dynamic factors include the Pacific Plate subduction and the indentation of the Philippine Sea Plate along the Taiwan Orogen to the east side of the South China Sea, and the Indian Plate oblique subduction and mid-ocean ridge subduction to the west side. They may also be responsible for the uplifting of the Tibetan Plateau and the related extrusions of continental blocks to the north side. At the same time, the mantle dynamics of deep-seated magma underplating, delamination, mantle plume and mantle-hydrated process should not be ignored. At last, this paper proposes one strike-slipping pull-apart model to explain the onset of the South China Sea Basin which is closely related to the tectonic evolution of the Pacific Tectonic Domain.%南海发育有众多的

  17. Seismic sequence and depositional evolution of slope basins in mid-northern margin of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LI Mingbi; JIN Xianglong; LI Jiabiao; DING Weiwei; FANG Yinxia; LIU Jianhua; TANG Yong

    2011-01-01

    As one of the biggest marginal seas in the western Pacific margin,the South China Sea (SCS) experienced continental riffing and seafloor spreading during the Cenozoic.The northern continental margin of the SCS is classified as a passive continental margin.However,its depositional and structural evolution remains controversial,especially in the deep slope area.The lack of data hindered the correlation between continental shelf and oceanic basin,and prevented the establishment of sequence stratigraphic frame of the whole margin.The slope basins in the mid-northern margin of SCS developed in the Cenozoic;the sediments and basin infill recorded the geological history of the continental margin and the SCS spreading.Using multi-channel seismic dataset acquired in three survey cruises during 1987 to 2004,combined with the data of ODP Leg 184 core and industrial wells,we carried out the sequence stratigraphic division and correlation of the Cenozoic in the middle-northern margin of SCS with seismic profiles and sedimentary facies.We interpreted the seismic reflection properties including continuity,amplitude,frequency,reflection terminals,and 15 sequence boundaries of the Cenozoic in the study area,and correlated the well data in geological age.The depositional environment changed from river and lake,shallow bay to open-deep sea,in correspondence to tectonic events of syn-rifting,early drifting,and late drifting stages of basin evolution.

  18. Early Pleistocene hominid teeth recovered in Mohui cave in Bubing Basin, Guangxi, South China

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; Richard Potts; HOU Yamei; CHEN Yunfa; WU Huaying; YUAN Baoyin; HUANG Weiwen

    2005-01-01

    Two hominid teeth recovered in Mohui cave are morphologically distinguished from Australopithecus in Africa, but close to Homo erectus in China. These teeth are therefore provisionally assigned to Homo erectus. The associated mammalian fauna include Gigantopithecus blacki, Nestoritherium sp., Sus xiaozhu, Sus peii and Ailuropoda microta, which are typical early Pleistocene taxa in South China. The general characteristics of the Mohui faunal assemblage are similar to the Longgupo site, which is dated to 2 Ma, implying a contemporaneity for the two sites. To date, compared with the discoveries in Africa, far fewer early Pleistocene hominid fossils have been recovered in Asia, and there are intensive controversies concerning their stratigraphic provenience and typological and temporal positions. The hominid fossils from Mohui cave, with their reliable biostratigraphic positions and distinct typological features, provide important evidence regarding the issue of early human origins and evolution.

  19. Platform margins, reef facies, and microbial carbonates; a comparison of Devonian reef complexes in the Canning Basin, Western Australia, and the Guilin region, South China

    Science.gov (United States)

    Shen, Jian-Wei; Webb, Gregory E.; Jell, John S.

    2008-05-01

    Devonian reef complexes were well developed in Western Australia and South China, but no detailed direct comparison has been made between reef building in the two regions. The regions differ in several respects, including tectonic, stratigraphic and palaeoceanographic-palaeogeographic settings, and the reef building styles reflect minor differences in reef builders and reef facies. Similarities and differences between the two reef complexes provide insights into the characteristics of platform margins, reef facies and microbial carbonates of both regions. Here we present a comparison of platform margin types from different stratigraphic positions in the Late Devonian reef complex of the Canning Basin, Western Australia and Middle and Late Devonian margin to marginal slope successions in Guilin, South China. Comparisons are integrated into a review of the reefal stratigraphy of both regions. Reef facies, reef complex architecture, temporal reef builder associations, 2nd order stratigraphy and platform cyclicity in the two regions were generally similar where the successions overlap temporally. However, carbonate deposition began earlier in South China. Carbonate complexes were also more widespread in South China and represent a thicker succession overall. Platforms in the Canning Basin grew directly on Precambrian crystalline basement or early Palaeozoic sedimentary rocks, but in South China, carbonate complexes developed conformably on older Devonian siliciclastic strata. Pre-Frasnian reef facies in South China had more abundant skeletal frameworks than in Canning Basin reefs of equivalent age, and Famennian shoaling margins containing various microbial reefs may have been more common and probably more diverse in South China. However, Late Devonian platform margin types have been documented more completely in the Canning Basin. Deep intra-platform troughs (deep depressions containing non-carbonate pelagic sediments — Nandan-type successions) that developed along

  20. South China Sea Challenge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China's attempts to solve disputes with ASEAN over the South China Sea help regional peace China's marine economy and security are currently faced with new challenges, requiring careful handling, especially in disputes with ASEAN countries and in promoting common development of the South China Sea. The outcome of how this is dealt with could undoubtedly pave the way for solutions to other oceanic disputes. The South China Sea is located south of

  1. 40Ar/39Ar ages of seamount trachytes from the South China Sea and implications for the evolution of the northwestern sub-basin

    Institute of Scientific and Technical Information of China (English)

    Xiaohu Li; Jiabiao Li; Xing Yu; Chunsheng Wang; Fred Jourdan

    2015-01-01

    A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the 40Ar/39Ar age of trachytic samples collected from the Shuangfeng seamounts in the northwestern sub-basin of the South China Sea. The two samples yielded plateau ages of 23.80 ? 0.18 and 23.29 ? 0.22 Ma, respectively, which indicate magmatic activity in late Oligocene which helpful constraints the expansion time of the northwest sub-basin. Previous studies suggested that the northwestern sub-basin and southwestern sub-basin have experienced a relatively consistent expansion in the NWeSE direction followed by a late expansion of the eastern sub-basin. We concluded that the expansion of the northwestern sub-basin began prior to ca. 24 Ma, which also implicated magmatic events of a late or stop expansion of the northwestern sub-basin combined with our results of 40Ar/39Ar age data and previous geophysical data.

  2. Thermal and cementation histories of Permian shelf-edge carbonate rocks in the Nanpanjiang Basin, South China

    Science.gov (United States)

    Halley, Robert B.; Parrish, Judith T.; Zahn, Xie; Wenhai, Hu; Scholle, Peter A.; Zhongrui, Su; Yirong, Zhang; Yunming, Huang; Guangxuan, Li

    1989-01-01

    As of 1984, the Nanpanjiang Basin of South China has had almost no exploration by drilling although oil seeps exist among its margins and producing wells occur in adjacent basins.  however, cooperative studies by petroleum geologists and geochemists of the United States and the People's Republic of China (1982-1984) show that calcite-cemented reef and fore-reef carbonate rocks near Ziyun contain bitumen in Upper Permian shelf-edge sediment.  the cementation history consists of three episodes: (1)precipitation of syndepositional marine cement (formerly botryoidal aragonnite and fibrous magnesian calcite); (2)precipitation of post-depositional early cement (radiaxial calcite); and (3)precipitation of late burial cement (white calcite spar).  Hydrocarbons were introduced into the rocks between cementation episodes 2 and 3.  Fluid inclusion analysis of secondary inclusions in the burial cement indicates that the rocks were heated to nearly 200 C after hydrocarbon migration and cementation episode 3.  Bitumen remains in the rocks as evidence of the earlier presence of liquid hydrocarbons.

  3. The structure and sedimentary sequence of intracratonic rift from Late Sinian to Early Cambrian in the Sichuan Basin, South China

    Science.gov (United States)

    Gu, Zhidong; Zhang, Baomin; Lu, Weihu; Zhai, Xiufen; Jiang, Hua

    2016-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze craton of South China, and there is developed an intracratonic rift from Late Sinian to Early Cambrian in the middle of Sichuan Basin, and the paper systematically discusses the structure and sedimentary sequence of the intracratonic rift based on the fields, drilling and seismic data, and so on. Detailed structural interpretation of 2D and 3D seismic profiles displays the development of two stages of intracratonic rift due to regional extension with the depth of 2000m, and plane distribution of intracratonic rift presents the V-pattern from the northwest to the southeast in the middle of Sichuan Basin with the width from 100km to 20km. The drilling data from the intracratonic rift shows the obvious thinning of Upper Sinian and thickening of Lower Cambrian. And field outcrops situated in the intracratonic rift reveal that the Upper Sinian is mainly composed of siliceous rock, shale and carbonate, with the thickness of less than 100m, but the thickness of Upper Sinian on the platform reaches 1000m by contrast; They also reveals that Lower Cambrian is mainly composed of shale, mudstone, and siltstone with the development of gravity current, and the thickness of Lower Cambrian reaches 2000m. The formation of intracratonic rift may be initiated by pre-existing basement weakness zone and deep mantle dynamics.

  4. Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

    Directory of Open Access Journals (Sweden)

    Daidai Wu

    2011-01-01

    Full Text Available Several authigenic minerals were identified by XRD and SEM analyses in shallow sediments from the Southeast Hainan Basin, on the northern slope of South China Sea. These minerals include miscellaneous carbonates, sulphates, and framboidal pyrite, and this mineral assemblage indicates the existence of gas hydrates and a methane seep. The assemblage and fabric features of the minerals are similar to those identified in cold-seep sediments, which are thought to be related to microorganisms fostered by dissolved methane. Chemical composition of pore water shows that the concentrations of SO42-, Ca2+, Mg2+, and Sr2+ decrease clearly, and the ratios of Mg2+ to Ca2+ and Sr2+ to Ca2+ increase sharply with depth. These geochemical properties are similar to those where gas hydrates occur in the world. All results seem to indicate clearly the presence of gas hydrates or deep water oil (gas reservoirs underneath the seafloor.

  5. Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

    Science.gov (United States)

    Zhang, Yong; Jia, Dong; Yin, Hongwei; Liu, Mancang; Xie, Wuren; Wei, Guoqi; Li, Yongxiang

    2016-02-01

    The organic-rich lower Silurian shale of the Longmaxi Formation in the Sichuan Basin is the most important target for shale-gas exploration in China. Most Paleozoic rocks of the Sichuan Basin have experienced extraordinarily pervasive remagnetizations. To test a hypothesized connection between hydrocarbon generation and remagnetization and contribute to shale-gas exploration in the region, we undertook an integrated magnetic, geochemical, and petrographic study of 160 specimens from the shale. The results suggest that the shale contains a reliable remanent magnetization (Dec = 41.4°, Inc = 40.8°, and α95 = 6.8°). The magnetization predates tilting, and the paleopole plots close to the Late Triassic segment of the south China apparent polar wander path. The rock magnetic data and scanning electron microscope (SEM) observations confirm that framboidal magnetites carry the bulk of the magnetization, which suggest a Late Triassic chemical remanent magnetization in the shale. 87Sr/86Sr and magnetic analyses indicate that the amount of magnetite was unaffected by fluid alterations around the veins but is strongly covariant with the amount of total organic matter. Moreover, SEM observations reveal possible evidence of the replacement of pyrite framboids by magnetite, probably in the presence of organic acids. These analyses, therefore, suggest that the remagnetization was caused by organic maturation rather than orogenic fluids and that the maturation occurred in the Late Triassic. This timing of organic maturation has been validated by independent modeling studies and provides important constraints on the complex thermal history of the Longmaxi Shale as well as contributing to shale-gas exploration efforts.

  6. Characterization of gas hydrate distribution using conventional 3D seismic data in the Pearl River Mouth Basin, South China Sea

    Science.gov (United States)

    Wang, Xiujuan; Qiang, Jin; Collett, Timothy S.; Shi, Hesheng; Yang, Shengxiong; Yan, Chengzhi; Li, Yuanping; Wang, Zhenzhen; Chen, Duanxin

    2016-01-01

    A new 3D seismic reflection data volume acquired in 2012 has allowed for the detailed mapping and characterization of gas hydrate distribution in the Pearl River Mouth Basin in the South China Sea. Previous studies of core and logging data showed that gas hydrate occurrence at high concentrations is controlled by the presence of relatively coarse-grained sediment and the upward migration of thermogenic gas from the deeper sediment section into the overlying gas hydrate stability zone (BGHSZ); however, the spatial distribution of the gas hydrate remains poorly defined. We used a constrained sparse spike inversion technique to generate acoustic-impedance images of the hydrate-bearing sedimentary section from the newly acquired 3D seismic data volume. High-amplitude reflections just above the bottom-simulating reflectors (BSRs) were interpreted to be associated with the accumulation of gas hydrate with elevated saturations. Enhanced seismic reflections below the BSRs were interpreted to indicate the presence of free gas. The base of the BGHSZ was established using the occurrence of BSRs. In areas absent of well-developed BSRs, the BGHSZ was calculated from a model using the inverted P-wave velocity and subsurface temperature data. Seismic attributes were also extracted along the BGHSZ that indicate variations reservoir properties and inferred hydrocarbon accumulations at each site. Gas hydrate saturations estimated from the inversion of acoustic impedance of conventional 3D seismic data, along with well-log-derived rock-physics models were also used to estimate gas hydrate saturations. Our analysis determined that the gas hydrate petroleum system varies significantly across the Pearl River Mouth Basin and that variability in sedimentary properties as a product of depositional processes and the upward migration of gas from deeper thermogenic sources control the distribution of gas hydrates in this basin.

  7. The linkage between longitudinal sediment routing systems and basin types in the northern South China Sea in perspective of source-to-sink

    Science.gov (United States)

    Su, Ming; Hsiung, Kan-Hsi; Zhang, Cuimei; Xie, Xinong; Yu, Ho-Shing; Wang, Zhenfeng

    2015-11-01

    Using bathymetric and seismic data, this study describes the morpho-sedimentary features in Qiongdongnan basin and southwest Taiwan collision basin, northern South China Sea and reveals the linkages between sediment routing system and basin types. The modern Central Canyon in the Qiongdongnan basin is located along the rift margin, and subparallel to the shelf-break southeast of Hainan Island. The modern Central Canyon develops along the basin axis (i.e., Xisha Trough) and longitudinally transports sediments eastward which are mainly supplied by northern continental slope. The Penghu Canyon in the southwest Taiwan collision basin is located along the collision boundary parallel to the strike of the adjacent uplifted Taiwan orogen. The Penghu Canyon develops along the tilting basin axis transporting sediments longitudinally southward to the deep-sea basin and Manila Trench. The Penghu Canyon is supplied with sediments from both flank Kaoping and South China Sea slopes where tributary canyons and channels transport sediments down-slope and feed the axial canyon. The certain basin types may be occupied by particular styles of sediment routing system. By comparing the morpho-sedimentary features and basin characteristics associated with the modern Central Canyon to that of the Valencia Channel in NW Mediterranean Sea, the longitudinal sediment routing system in rift basin type can be determined. In contrast, the longitudinal sediment routing systems in collision setting can be represented by the comparable examples of Penghu Canyon in southwest Taiwan collision basin and Markham Canyon in western Solomon Sea. The rift type sediment routing system is characterized by an axial canyon with a single sediment supply from land drainage margin. In contrast, sediment routing system in collision type basins consists of an axial canyon and dual sediment supplies from flank adjacent slopes. The axial canyons in collision basins are more active than that of the rift basin due to

  8. Characteristics and Origin of Yacheng Gas Field in Qiongdongnan Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The Yacheng gas field lies in the foot wall of the No. 1 fault, the boundary fault between the Yinggehai and Qiongdongnan basins. An overpressured system developed in the Meishan Formation near the No. 1 fault in the gas field and in the adjacent Yinggehai basin. Away from this fault into the Qiongdongnan basin, the overpressure diminishes. Below 3 600 m in the gas field, an obvious thermal anomaly occurs. The gases show obvious compositional heterogeneities which reflect reservoir-filling process and origin of the gas field. The gas field was charged from both the Qiongdongnan and the Yinggehai basins but mainly from the former. Hydrocarbons sourced from the Qiongdongnan basin have relatively low maturities while hydrocarbons from the Yinggehai basin have relatively high maturities.

  9. South China Sea

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chinese Foreign Minister Yang Jiechi warned against attempts to "in-ternationalize" the issue of the South China Sea, where China has territorial disputes with some ASEAN member states, including Viet Nam and the

  10. Formation mechanism of the Qiongdongnan basin northwest of the South China Sea-dating the sinistral slip of the Red River Fault Zone

    Science.gov (United States)

    Sun, Z.; Jiang, J.; Xie, W.

    2010-12-01

    Locating on the northwestern margin of the South China Sea, the Qiongdongnan basin is a NE-trending rift zone in general. Bounding with the NW-trending Yinggehai basin and the Red River- East Vietnam Fault Zone to the west, the evolution of the Qiongdongnan basin bears large amounts of information about the slip of the Red River Fault zone. Combined the geological analysis with analogue modeling experiments, we suggest that the evolution of the Qiongdongnan is controlled not only by the southeastward to south southeastward extension, but also by the sinistral slip of the Red River Fault zone. The central depression of the Qiongdongnan basin is controlled mainly by the southeastward to south southeastward extension, while the southern depression developed under the combined stress filed of southeastward extension and the dextral slip along the NNW-trending Red River fault zone. The northern depression was formed by the combined effect of the sinistral slip along the Red River Fault Zone and the southeastward extension. According to the age of the shear fault starting to develop in the southwest of the Qiongdongnan basin, as well as the age for the northwestern part to develop, the sinistral slip of the Red River Fault zone began around early oligocene, later than the rifting of the Qiongdongnan basin. The sinistral slip rate of the Red River Fault zone during early Oligocene may be smaller than the displacement rate of the Qiongdongnan basin, but become reversed thereafter, which in turn caused tectonic inversion and folding along the western segment of the Qiongdongnan basin, and NW- to NNW-trending Rediel faults from late Oligocene to middle Miocene. Through the deformation history of the Qiongdongnan basin, we defined the sinistral slip stage Indochina along the Red River Fault zone from about 36Ma to 16Ma, and further a rapid slip occurring after 30Ma.

  11. Marine Carbon-Sulfur Biogeochemical Cycles during the Steptoean Positive Carbon Isotope Excursion (SPICE) in the Jiangnan Basin, South China

    Institute of Scientific and Technical Information of China (English)

    Yang Peng; Yongbo Peng; Xianguo Lang; Haoran Ma; Kangjun Huang; Fangbing Li; Bing Shen

    2016-01-01

    ABSTRACT:Global occurrences of Steptoean Positive Carbon Isotope Excursion (SPICE) during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evolution. In previous studies, SPICE has been reported from the Jiangnan slope belt in South China. To evaluate the bathymetric extent of SPICE, we investigate the limestone samples from the upper Qingxi Formation in the Shaijiang Section in the Jiangnan Basin. Our results show the positive excursions for both carbonate carbon (δ13C) and organic carbon (δ13Corg) isotopes, as well as the concurrent positive shifts in sulfur isotopes of carbonate associated sulfate (CAS, δ34SCAS) and pyrite (δ34Spyrite), unequivocally indicating the presence of SPICE in the Jiangnan Basin. A 4‰increase inδ13Ccarb of the Qingxi limestone implies the increase of the relative flux of organic carbon burial by a factor of two. Concurrent positive excursions inδ34SCAS andδ34Spyrite have been attributed to the enhanced pyrite burial in oceans with extremely low concentration and spatially heterogeneous isotopic composition of seawater sulfate. Here, we propose that the seawater sulfur isotopic heterogeneity can be generated by volatile organic sulfur compound (VOSC, such as methanethiol and dimethyl sulfide) formation in sulfidic continental margins that were widespread during SPICE. Emission of 32S-enriched VOSC in atmosphere, followed by lateral transportation and aerobic oxidation in atmosphere, and precipitation in open oceans result in a net flux of 32S from continental margins to open oceans, elevatingδ34S of seawater sulfate in continental margins. A simple box model indicates that about 35%to 75%of seawater sulfate in continental margins needs to be transported to open oceans via VOSC formation.

  12. Study on Basin-Filling and Reservoir Sedimentology of Zhu Ⅲ Depression of Pearl River Mouth Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Through basin-filling analysis, one coarsening-upward and two fining-upward sequences have been identified in Zhu Ⅲ depression. In accondance with the general model proposed by Ravnas and Steel (1998), the basin-filling has two large cycles-rift (sediment-balanced and -overfilied)and postrift (sediment-underfilled and -starved). During the rifting process, the rifted lake developed through three stages: early, climax and late. The sedimentary characteristics of reservoir rocks show that barrier bar, lagoon and tidal channel facies well developed in Zhuhai Formation;offshore, tidal and barrier bar well developed in Zhujiang Formation. Neighborly, Shenhu , Wenchang and Enping formations deposited in rifted lakes during Paleogene time ; Zhujiang Formation deposited in bay, lagoon and shorefnce in late Paleogene. Zhujiang and other formations deposited in offshore and open shallow sea to shelf.

  13. Preferential Petroleum Migration Pathways in Eastern Pearl River Mouth Basin,Offshore South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yu Jianning; Zou Huayao; Gong Zaisheng

    2009-01-01

    Secondary petroleum migration in the eastern Pearl River Mouth basin was modeled using the three-dimensional PATHWAYSTM model,which assumes that the positions of petroleum migration pathways are controlled by the morphology of the sealing surfaces.The modeling results have accurately predicted the petroleum occurrences.Most commercial petroleum accumulations are along the predicted preferential petroleum migration pathways (PPMP),and most large fields (petroleum reserves greater than 1×108 t) have more than one preferential petroleum migration pathways to convey petroleum to the traps.The lateral migration distance for oil in the LH11-1 field,the largest oilfield so far discovered in the Pearl River Mouth basin,was more than 80 km.The case study suggests that in lacustrine fault basins,petroleum can migrate over a long distance to form large oilfields without driving force from groundwater flow.The focusing of petroleum originating from a large area of the generative kitchens into restricted channels seems to be essential not only for long-range petroleum migration in hydrostatic conditions,but also for the formation of large oil or gas fields.The strong porosity and permeability heterogeneities of the carrier beds and the relatively high prediction accuracy by a model that does not take into consideration of the effect of heterogeneity suggest that the positions of petroleum migration pathways in heterogeneous carrier beds with relatively large dipping angles are determined primarily by the morphology of the sealing surfaces at regional scales.

  14. Fast Deposition of Small River Particles on the NE South China Sea Slope Basin Since the Last Glacial Maximum

    Science.gov (United States)

    Lin, S.; Cheng, W. Y.; Hsieh, I. C.

    2015-12-01

    Huge quantities of small rivers derived suspended particles are exporting to the ocean from oceanic islands at the present time. Depending on location and proportion of shelf/slope area, a major fraction of small river particles may by-pass the shelf region, transport and deposit on the deep ocean basin. Major mechanisms driving those huge quantities of small river derived particles to the ocean are quantity of precipitation from monsoon and those from short period of tropical cyclone. Although data demonstrate that deeper part of the South China Sea, SCS, is the major final burial location of the river derived particles from the island of Taiwan, it is not sure if this was the same during the glaciation when monsoon and climatic conditions were drastic different from the present time. The purpose of this study is to understand history of small river derived sediment export and deposition during climatic change. A long piston core with length of ~35 meter was taken on r/v Marion DuFresne on a slope basin offshore SW Taiwan. We have measured density, magnetic susceptibility with multi-sensor core logger, MSCL, and organic, inorganic carbon, C/N ratio, biogenic silica as well as grain sizes. Foraminifera (Orbulina universa, Globigerinoides sacculifer and Globigerinoides conglobatus) were picked and measured carbon 14 for age determination. Two different types of processes control sediment deposition in our study site, steady state and event driven sedimentation. Our results demonstrated that sedimentation rates were consistent during each major periods, the Holocene (present to 10k year) and the transition (10-20 k year) period, but, difference existed in between the two. Sedimentation rate was about twice faster during the transition period (20-10k year) than that at the Holocene (10-present time) at our study site. A number of spikes existed in our study site, probably a result of turbidite overflow from the adjacent canyon. Frequency and total thickness of event

  15. Mesozoic deformation in the Chaoshan Depression of the Pearl River Mouth Basin, northern South China Sea

    Science.gov (United States)

    Zhang, Jiangyang; Sun, Zhen; Zhang, Yunfan; Li, Fucheng

    2016-05-01

    Newly collected, high resolution multi-beam sonar data are combined with previous bathymetry data to produce an improved bathymetric map of Shatsky Rise oceanic plateau. Bathymetry data show that two massifs within Shatsky Rise are immense central volcanoes with gentle flank slopes declining from a central summit. Tamu Massif is a slightly elongated, dome-like volcanic edifice; Ori Massif is square shaped and smaller in area. Several down-to-basin normal faults are observed on the western flank of the massifs but they do not parallel the magnetic lineations, indicating that these faults are probably not related to spreading ridge faulting. Moreover, the faults are observed only on one side of the massifs, which is contrary to expectations from a mechanism of differential subsidence around the massif center. Multi-beam data show many small secondary cones with different shapes and sizes that are widely-distributed on Shatsky Rise massifs, which imply small late-stage magma sources scattered across the surface of the volcanoes in the form of lava flows or explosive volcanism. Erosional channels occur on the flanks of Shatsky Rise volcanoes due to mass wasting and display evidence of down-slope sediment movement. These channels are likely formed by sediments spalling off the edges of summit sediment cap.

  16. Features of Late Cenozoic Deepwater Sedimentation in Southern Qiongdongnan Basin,Northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yuan Shengqiang; Yao Genshun; Lü Fuliang; Hu Bing; He Xiaosu; Wang Bin; Li Li

    2009-01-01

    Based on high resolution 2D and 3D seismic data acquired in recent years,using sequence stratigraphy analysis and geophysical methods,we discuss the features of Late Cenozoic deepwater sedimentation in the southern Qiongdongnan (琼东南) basin.The study area entered a bathyal slope environment in the Miocene.The channel developed in the Sanya (三亚) Formation was controlled by a fault break,and its shingled seismic characteristics represent multiple erosion and fill,which may indicate that turbidite current developed in the slope environment.The polygon faults found in mudstone of the Meishan (梅山) Formation represent the deepwater hungry sedimentary environment.The large-scale channels developed on the top of HuangUu (黄流) Formation could be the result of a big sea level drop and an increase of sediment supply.The fantastic turbidite channel developed in Late Quaternary in the slope environment has "fan-like" body and long frontal tiny avuision channel The analysis of these features suggests that the sediment supply of the study area in the post-rifting period was dominant from the Vietnam uplift in the southwest.These deepwater sedimentary features could be potential reservoirs or migration pathways for deepwater petroleum systems.

  17. Early Triassic calcimicrobial mounds and biostromes of the Nanpanjiang basin, south China

    Science.gov (United States)

    Lehrmann, Daniel J.

    1999-04-01

    Early Triassic framestones were discovered in the interior of an isolated, marine carbonate platform in the Nanpanjiang basin. The framestones occur in two horizons: (1) the lowermost Triassic (Griesbachian), as biostromes as much as 15 m thick, and (2) the upper part of the Lower Triassic (Smithian or Spathian) as isolated domal or inverted conical mounds as much as 1.5 m thick. The mounds and biostromes consist of a rigid calcimicrobial framework enclosing a network of internal cavities, 1 to 3 cm across, filled with peloidal-skeletal sediment. The framework is made of irregular-to-tufted masses of chambered-to-clotted micrite structures referable to Renalcis, a calcified coccoid cyanobacteria. The framework is reinforced by microbial induced micritic crusts as well as marine cement. Metazoan fossils within the framework include gastropods, bivalves, ostracodes, spirorbids, and brachiopods. The Early Triassic is widely considered to have been a global gap in reef and reef mound development. The global reef gap concept has formed the foundation of models of reef evolution and of the reorganization of reef ecosystems after the end-Permian extinction. These models should be revised to account for the existence of Early Triassic calcimicrobial mounds and biostromes discussed herein.

  18. Long-term meteorological and hydrological dryness and wetness conditions in the Zhujiang River Basin, South China

    Directory of Open Access Journals (Sweden)

    T. Fischer

    2012-09-01

    Full Text Available Floods and droughts are frequently causing large economic losses in China. These conditions vary in space, time, and magnitude. In this study, long-term meteorological and hydrological dryness and wetness conditions are analyzed for the Xijiang River Basin which is the largest tributary of the Zhujiang (Pearl River. A very similar inter-annual course of precipitation and discharge can be observed. The standardized precipitation index (SPI is used to show dryness and wetness pattern in the six sub-basins of the Xijiang River. The SPI-24 correlates high with the standardized discharge index (SDI-24 for Gaoyao hydrological station at the mouth of Xijiang River. Distinct long-term dryness and wetness sequences are found in the time series for the SPI-24 and SDI-24. The principal component analysis reveals many spatial interdependencies in dryness and wetness conditions for the sub-basins and explains some spatio-temporal disparities. Moderate dryness conditions have a larger spatial impact than moderate wetness conditions in the sub-basins. The loading pattern of the first principal component shows that the correlation with the entire Xijiang River Basin is highest in the eastern and lowest in the western sub-basins. Further spatial dipole conditions explain the spatio-temporal heterogeneity of dryness and wetness conditions. Accordingly, the precipitation in the eastern sub-basins contributes more to the hydrological wetness conditions than in the western sub-basins, which mainly contribute to dryness patterns.

    The spectral analysis for the SPI-24 (entire Xijiang River Basin and SDI-24 shows similar peaks for periods of 11–14.7 yr, 2.8 yr, 3.4–3.7 yr, and 6.3–7.3 yr. The same periods can be found for the SPI-24 of Xijiang River's six sub-basins with some variability in the magnitude. The wavelet analysis shows that the most significant periods are stable over time since the 1980s. The extrapolations of the reconstructed time series

  19. Post-rift tectonic reactivation and its effect on deep-water deposits in the Qiongdongnan Basin, northwestern South China Sea

    Science.gov (United States)

    Mao, Kainan; Xie, Xinong; Xie, Yuhong; Ren, Jianye; Chen, Hui

    2015-09-01

    The post-rift evolution of extensional basins is traditionally thought to be dominated by thermal subsidence due to cessation of the major fault activity during the post-rift stage. The Qiongdongnan Basin, which is located in the northwestern continental margins of the South China Sea, has exhibited significant deviations from typical post-rift characteristics. In the basin, a distinct tectonic reactivation occurred since the Late Miocene (11.6 Ma). Three notable aspects of the observed tectonic reactivation during the post-rift stage include, (1) pre-existing fault reactivation, (2) multiple large-scale magmatic intrusions, and (3) rapid post-rift subsidence. During this period the basin infill significantly changed in depositional environments shifting rapidly from littoral-neritic to bathyal-abyssal environments since Late Miocene. The pre-existing fault activity along the No. 2 fault of the basin resulted in the formation of initial shelf breaks and led to the development of continental slope. In addition, the pre-existing faults along the Central Depression zone created a small sub-basin with distinctive axial negative topography characteristics formed between structural highs. These geomorphological changes led to the formation of the Central Canyon. Large-scale magmatic intrusions occurred along the fault zone in the Central Depression of the basin during the post-rift stage. Those deviations, as evidenced from pre-existing fault reactivation, magmatic intrusions, and rapid post-rift subsidence in the Qiongdongnan Basin is believed to be related to the Hainan Plume event.

  20. Low Angle Normal Fault System Controls the Structure Evolution of Baiyun Deepwater Basin and Its Lithosphere Thinning, Northern South China Sea

    Science.gov (United States)

    Zhao, Y.; Ren, J.; Yang, L.

    2015-12-01

    The discovery of the transition area from ~30 km to weakly thinned continental crust (<12 km) in Baiyun deepwater basin, Northern South China Sea leads to two questions: What controls extreme crustal thinning and what is the nature of Baiyun basin. The 3D seismic data newly acquired show that Baiyun basin is an asymmetric half graben mainly controlled by a set of north-dipping normal faults converging in deep. By employing the principle of back-stripping, we estimate the fault dips and slip amount would be in the absence of post-rift sediments and seawater loading. Results show these Middle Eocene faults were extremely active, with a high accumulation horizontal displacement (> 10 km) and an initial very low angle (<7°), followed by a rotated into sub-horizontal. A general scenario for extension of the uppermost continental crust probably includes simultaneous operation of low angle normal fault (F1) as well as parallel arrays of step-faults (domino-faults, f2-f9). Under such a scenario, it shows no obvious extension discrepancy in Baiyun basin. Our results indicate that Baiyun sag preserves information recording the continent thinning before the seafloor spreading, and it could be an abandoned inner rifted basin.

  1. South China Sea.

    Science.gov (United States)

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  2. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  3. Petroleum Exploration Prospects in Erlian Basin,China

    Institute of Scientific and Technical Information of China (English)

    Fei Baosheng

    1994-01-01

    @@ Erlian Basin is located in the middle prairie,Inner Mongolia Autonomous Region, the north border of China. Teetonieally, Erlian Basin is to the south of Bayinbaoligel Uplift and the north is the Wendouer Temple Uplift. In the east of the basin, there is Daxinganling Uplift and the west is Soulunshan Uplift. The basin covered an area of 100 000 km2, is a Mesozoic Cenozoic graben (rift)basin that evolved on the folded basement of Heveynian geosyncline.

  4. The South China Sea Deep: Introduction

    Science.gov (United States)

    Wang, Pinxian; Li, Qianyu; Dai, Minhan

    2015-12-01

    The South China Sea (SCS) has increasingly become a global focus in ocean research and hydrocarbon explorations. Over the last two decades, at least 17 international cruises including two ODP/IODP expeditions were conducted in the SCS, and more than 2000 exploratory wells were drilled (Wang et al., 2014a). While its sedimentary basins on the continental shelf and slope are explored for offshore resources, the deep basin below 3500 m in depth that overlies the basaltic oceanic crust preserves the key to understanding their formation and development. In order to better understand the life history and functional system of the marginal sea, a major research program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep" for short, was launched in January 2011 by the National Natural Science Foundation (NSFC) of China. This venture represents the first ever large-scale basic-research program in ocean science in the country (Wang, 2012).

  5. Improving Seasonal Precipitation Predictions over the East River Basin, South China by Using Bias-corrected CFSv2 Forecasts

    Science.gov (United States)

    Wang, D.; Zhu, C.; Wu, Y.; Lin, K.; Liu, B.; Chen, Z.; Xinjun, T.; Huang, M.

    2015-12-01

    East River is one the major tributaries of Peal River, the third largest river over China. It is the most important water resource for agriculture, industry, and commerce in the Pearl River Delta. The water demand has dramatically increased with rapid population growth and booming economic development in this region. To meet the demand of water supply, the East River basin administration has conducted the water quantity operation over the basin since 2008. However, the operation target has been hardly achieved largely due to poor precipitation predictions. We try to improve seasonal precipitation predictions by correcting the bias of the NCEP CFSv2 forecasts. A variety of bias correction methods are applied to correct CFSv2 forecasts based on a long term datasets of gauge observations and CFSv2 reforecasts. The proper bias methods are selected for the flood and the dry season respectively based on evaluation results. The CFSv2 based predictions would help in making a reasonable water quantity operation plan and improving operational performance over the East River basin.

  6. Layer-block tectonics of Cenozoic basements and formation of intra-plate basins in Nansha micro-plate,southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Hailing; XIE Guofa; LIN Qiujin; ZHENG Hongbo; LIU Yingchun

    2009-01-01

    Layer-block tectonics (LBT) concept, with the core of pluralistic geodynamic outlook and multi-layer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history of global tectonic system controlled by global geodynamics system. The LBT concept is applied to study the lithospheric tectonics of the southern South China Sea (SCS). Based on the analysis of about 30 000 km of geophysical and geological data, some layer-blocks in the Nansha micro-plate can be divided as Nansha ultra-crustal layer-block, Zengmu crustal layer-block, Nanwei (Rifleman bank)-Andu (Ardasier bank) and Liyue (Reed bank)-North Palawan crustal layer-blocks, Andu-Bisheng and Liyue-Banyue basemental layer-blocks. The basic characteristics of the basemental layer-blocks have been dicussed, and three intra-plate basin groups are identified. The intra-plate basins within Nansha micro-plate can be divided into three basin groups of Nanwei-Andu, Feixin-Nanhua, and Liyue-North Palawan based on the different geodynamics. In the light of pluralistic geodynamic concept, the upheaving force induced by the mid-crust plastic layer is proposed as the main dynamical force which causes the formation of the intra-plate basins within the Nansha micro-plate. Finally, models of a face-to-face dip-slip-detachment of basemental layer-block and a unilateral dip-slip-detachment of basemental layer-block are put forward for the forming mechanisms of the Nanwei-Andu and Liyue-North Palawan intra-plate basin groups, respectively.

  7. Insights from heavy minerals and zircon U-Pb ages into the middle Miocene-Pliocene provenance evolution of the Yinggehai Basin, northwestern South China Sea

    Science.gov (United States)

    Jiang, Tao; Cao, Licheng; Xie, Xinong; Wang, Zhenfeng; Li, Xushen; Zhang, Yingzhao; Zhang, Daojun; Sun, Hui

    2015-08-01

    The well-preserved Cenozoic sedimentary record in the Yinggehai Basin, South China Sea, is suitable to explore the tectonic and climatic evolution of SE Asia. Red River, a large-scale fluvial system in this region, was previously regarded as the major sediment source for the basin. Here we combine heavy mineral analysis and detrital zircon U-Pb dating to shed new light on the middle Miocene-Pliocene provenance evolution at a basin scale. The results clearly reveal potential source areas additional to the Red River. Sediments have been delivered to the proximal areas from Hainan Island, as indicated by the high zircon content and the Yanshanian U-Pb ages in the southern segment of the Yingdong Slope. A provenance from Central Vietnam is explicitly discerned in the upper Miocene of the Central Depression, where sediments are characterized by few metamorphic heavy minerals and the U-Pb age pattern peaking at around 250 Ma and 440 Ma. Coeval large-scale relative sea-level fall and rapid exhumation along the Vietnamese margin together may have facilitated this long-distance sediment transport. Provenance of sediments from the Red River seems to change over time. Song Lo River, on the north side of the main stream, probably flowed from the NE and carried Neoproterozoic-early Paleozoic zircons to the Yinggehai Basin during the middle Miocene. Since the late Miocene, rocks along the Red River Fault Zone have become the dominant source. Subsequently, widespread metamorphic minerals in the Central Depression of the Yinggehai Basin, combined with the strong river incision and high offshore sedimentation rates, indicate an increased sediment supply from the Red River in the Pliocene.

  8. Types, Evolution and Pool-Controlling Significance of Pool Fluid Sources in Superimposed Basins: A Case Study from Paleozoic and Mesozoic in South China

    Institute of Scientific and Technical Information of China (English)

    Xu Sihuang; Mei Lianfu; Yuan Caiping; Ma Yongsheng; Guo Tonglou

    2007-01-01

    Having multiple tectonic evolution stages, South China belongs to a superimposed basin in nature. Most marine gas pools became secondary pools. The pool fluid sources serve as the principal pool-controlling factors. On the basis of eight typical petroleum pools, the type, evolution in time-space,and the controlling of petroleum distribution of pool fluid sources are comprehensively analyzed. The main types of pool fluid sources include hydrocarbon, generated primarily and secondly from source rocks, gas cracked from crude oil, gas dissolved in water, inorganic gas, and mixed gases. In terms of evolution, the primary hydrocarbon was predominant prior to Indosinian; during Indosinian to Yenshanian the secondary gas includes gas cracked from crude oil, gas generated secondarily, gas dissolved in water, and inorganic gas dominated; during Yenshanian to Himalayan the most fluid sources were mixed gases. Controlled by pool fluid sources, the pools with mixed gas sources distributed mainly in Upper Yangtze block, especially Sichuan (四川) basin; the pools with primary hydrocarbon sources distributed in paleo-uplifts such as Jiangnan (江南), but most of these pools became fossil pools; the pools with secondary hydrocarbon source distributed in the areas covered by Cretaceous and Eogene in Middle-Lower Yangtze blocks, and Chuxiong (楚雄), Shiwandashan (十万大山), and Nanpanjiang (南盘江) basins; the pools with inorganic gas source mainly formed and distributed in tensional structure areas.

  9. Sequence Stratigraphy and Sedimentary Facies of Lower Oligocene Yacheng Formation in Deepwater Area of Qiongdongnan Basin, Northern South China Sea:Implications for Coal-Bearing Source Rocks

    Institute of Scientific and Technical Information of China (English)

    Jinfeng Ren; Hua Wang; Ming Sun; Huajun Gan; Guangzeng Song; Zhipeng Sun

    2014-01-01

    -bearing characteristics in the lower exploration deepwater area of South China Sea.

  10. Development of Tertiary Basins of SE Asia from the South China Sea to the Andaman Sea region ; a comparative view on structure and timing

    Science.gov (United States)

    Pubellier, Manuel; Sautter, Benjamin

    2016-04-01

    Basins of SE Asia have developed since the end of Cretaceous times to the detriment of a Mesozoic andean arc which surrounded Sundaland. The arc was broader in the Eastern part along the Pacific Subduction Zone including theSouth China Sea (SCS), than in the Western part along the Sumatra Subduction Zone (Myanmar, Andaman Sea (AS), Malay Peninsula). By the end of the Upper Cretaceous, this arc died out and a widespread rifting with astonishing resemblances started in the whole Sundaland. We compare and discuss the basins similarities and differences in structure and timing between the two sides. A relaxation stage is evidenced in Western Sunda, represented by poorly exposed Late Cretaceous red beds filling the pre-existing morphostructures without clear fault-controlled basins. These deposits are also observed on seismic data offshore in the Gulf of Thailand and AS). On the opposite side along the Chinese margin, thick molasse-type deposits of Late Cretaceous age are on the contrary well expressed offshore and restricted to narrow valleys, indicating that stretching had already begun. There, the Paleogene is marked by strong extension with large crustal blocks rotated by often counter-regional normal faults creating half grabens. Crust was extended and extremely thinned particularly around the SCS. Basins reached the spreading stage in the Celebes Sea, the North Makassar basin and the SCS. On the western side, this period corresponds to narrow deep grabens (e.g. Mergui basins and part of western Malacca) with continental deposits, meaning that the stretching was localized. There, thinning of the crust took place during the Oligocene up to the Middle Miocene where large basins develop mostly to the outer edges of the Yenshanian Arc. Extension resumed in the Pliocene with the opening of the Andaman basin in an even more external position. To the eastern side the uppermost Miocene and the Pliocene were marked mostly by a deepening of the margins and the SCS ocean

  11. Seismic features and evolution of a late Miocene submarine channel system in the Yinggehai basin, northwestern South China Sea

    Science.gov (United States)

    Sun, H.; Jiang, T.; Wang, Z.; Zhang, Y.

    2014-12-01

    Submarine channel is one of key conduits for coarse terrigenous clastic sediments to abyssal plain, which provides the possibility for deepwater hydrocarbon exploration. Recently, a new high-quality 3D seismic data is acquired in south Yinggehai basin (YGHB) and the detailed interpretations on those seismic profiles as well as RMS amplitude attributes and variance slices reveal a submarine channel system developed in late Miocene, which could be supplied from Hainan Island via turbidity currents so that it would be filled with sand-rich turbidites as good hydrocarbon reservoir. Based on the integration between regional seismic survey and some boreholes, the investigations on its infilling architectures and depositional processes are carried out. The results show that it composes two converged submarine channels with two channelized submarine fans to their west and the main submarine channel (MSC) is characterized by a downstream increasing width and is infilled by sediments with high amplitude seismic facies, which could be originated from channelized submarine fans. Furthermore, the complicated depositional processes around the confluence region of these two channels are pointed out and the interactions between the submarine channel system and nearby channelized submarine fans are discussed. The detailed illustration on the seismic features and depositional processes of the subsurface submarine system provides us better understanding deepwater sedimentary dynamics and would be more benefit for the hydrocarbon exploration in similar deepwater area around the world.

  12. Spreading Dynamics and Sedimentary Process of the Southwest Sub-basin, South China Sea: Constraints from multi-channel seismic data and IODP Expedition 349

    Science.gov (United States)

    Ding, Weiwei; Li, Jiabiao; Clift, Peter

    2016-04-01

    Neotectonic and sedimentary processes in the South China Sea abyssal basin are still debated because of the lack of drilling evidence to test competing models. In this study, we interpreted four multi-channel seismic profiles across the Southwest Sub-basin (SWSB) and achieved stratigraphic correlation with new drilling data from Integrated Ocean Discovery Program (IODP) Expedition 349. Neogene sediments are divided into four stratigraphic units, each with distinctive seismic character. Sedimentation rate and lithology variations suggest climate-controlled sedimentation. In the late Miocene winter monsoon strength and increased aridity in the limited accumulation rates in the SWSB. Since the Pliocene summer monsoons and a variable glacial-interglacial climate since have enhanced accumulation rates. Terrigeneous sediments in the SWSB are most likely derived from the southwest. Three basement domains are classified with different sedimentary architectures and basement structures, including hyper-stretched crust, exhumed subcontinental mantle, and steady state oceanic crust. The SWSB has an asymmetric geometry and experienced detachment faulting in the final stage of continental rifting and exhumation of continental mantle lithosphere. Mantle lithospheric breakup post-dates crustal separation, delaying the establishment of oceanic spreading and steady state crust production.

  13. A preliminary biogeochemistry-based quantification of primary productivity of end-Permian deep-water basin in Dongpan Section ,Guangxi ,South China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yang; HE Weihong; FENG Qinglai

    2007-01-01

    In this Paper,the mean primary productivity of the Talung Formation in the deep-water basin(50-500 m depth)of Dongpan,Guangxi,South China,was calculated,of the content of the trace element Cu.Results showed that the primary productivity obtained was comparable with the previously-reported data for the black shale of the Phosphoria Formation,a Permian phosphate deposit in the northwest United States,and also similar to that of the modern deposit in the Cariaco basin,Venezuela.It was observed that the primary productivity increased with the enhanced abundance of algae and photosynthetic bacteria,and with the decrease in both the radiolarian individuals and the body size of brachiopods during the faunal mass extinction.This ecological coupling indicates that the changes of primary productivity are closely related to the propagation and the decline of producers(algae and bacteria),and that consumers(radiolarians and brachiopods)probably have little influence on the changes of primary productivity.

  14. Analyzing the water budget and hydrological characteristics and responses to land use in a monsoonal climate river basin in South China

    Science.gov (United States)

    Wu, Yiping; Chen, Ji

    2013-01-01

    Hydrological models have been increasingly used by hydrologists and water resource managers to understand natural processes and human activities that affect watersheds. In this study, we use the physically based model, Soil and Water Assessment Tool (SWAT), to investigate the hydrological processes in the East River Basin in South China, a coastal area dominated by monsoonal climate. The SWAT model was calibrated using 8-year (1973–1980) record of the daily streamflow at the basin outlet (Boluo station), and then validated using data collected during the subsequent 8 years (1981–1988). Statistical evaluation shows that SWAT can consistently simulate the streamflow of the East River with monthly Nash–Sutcliffe efficiencies of 0.93 for calibration and 0.90 for validation at the Boluo station. We analyzed the model simulations with calibrated parameters, presented the spatiotemporal distribution of the key hydrological components, and quantified their responses to different land uses. Watershed managers can use the results of this study to understand hydrological features and evaluate water resources of the East River in terms of sustainable development and effective management.

  15. Thermodynamic Modeling of Fluid-Bearing Natural Gas Inclusions for Geothermometer and Geobarometer of Overpressured Environments in Qiongdongnan Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    It is a very difficult problem to directly determine fluid pressure during hydrocarbon migration and accumulation in sedimentary basins. pVt modeling of coupling hydrocarbon fluid inclusion of its coeval aqueous fluid inclusion provides a powerful tool for establishing the relationship of formation pressure evolution with time. Homogenization temperature of fluid inclusion can routinely be measured under microthermometric microscopy. Crushing technique has been employed to obtain the composition of fluid inclusions, and the commercial software VTFLINC easily and rapidly completes the construction of p-t phase diagram. The minimum trapping pressure of hydrocarbon fluid inclusion would be then determined in the p-t space. In this paper, three samples of YC21-1-1 and YC21-1-4 wells at YC21-1 structural closure, Qiongdongnan basin, South China Sea, were selected for the pVt modeling practice, and the formation pressure coefficient (equals to fluid pressure/hydrostatic pressure) changing trend with time has primarily been established. The modeling results also indicate that the reservoirs of Lingshui and Yacheng formations in YC21-1 structure are within a very high potential system and would have undergone a discharging of thermal fluids through top seal rupture, which depicts that there is a very high risk for natural gas exploration in this area.

  16. A comparison study of summer-time synoptic-scale waves in South China and the Yangtze River basin using the TRMM Multi-Satellite Precipitation Analysis daily product

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998―2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum analysis method is applied. The results indicate that synoptic-scale waves appearing in South China prominently propagate westward within a zonal wavenumber range of 9―21 and a frequency range of-0.12―-0.22 cycles day-1, while those in the Yangtze River basin primarily move eastward with the same characteristic wavenumbers of 9―21, but within a frequency range of 0.2―0.29 cycles day?1. Zonal and meridional distributions, and seasonal variations of these waves are further explored and compared. It shows that summer-time synoptic-scale waves in the South China result from the northward migration and oscillation of the Intertropical Convergence Zone (ITCZ) in the western Pacific, whereas the ones in the Yangtze River basin are generally related to the synoptic troughs within the westerly flow, originating from the Qinghai-Tibet Plateau.

  17. A comparison study of summer-time synoptic-scale waves in South China and the Yangtze River basin using the TRMM Multi-Satellite Precipitation Analysis daily product

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998-2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum analysis method is applied. The results indicate that synoptic-scale waves appearing in South China prominently propagate westward within a zonal wavenumber range of 9-21 and a frequency range of -0.12--0.22 cycles day?1, while those in the Yangtze River basin primarily move eastward with the same characteristic wavenumbers of 9-21, but within a frequency range of 0.2-0.29 cycles day-1. Zonal and meridional distributions, and seasonal variations of these waves are further explored and compared. It shows that summer-time synoptic-scale waves in the South China result from the northward migration and oscillation of the Intertropical Convergence Zone (ITCZ) in the western Pacific, whereas the ones in the Yangtze River basin are generally related to the synoptic troughs within the westerly flow, originating from the Qinghai-Tibet Plateau.

  18. 3D seismic structure of the Zhenbei-Huangyan seamount chain in the East sub-basin of the South China Sea and its mechanism of formation

    Science.gov (United States)

    Zhao, M.; Wang, J.; Qiu, X.; Sibuet, J. C.; He, E.; Zhang, J.

    2015-12-01

    The post-spreading volcanic ridge (PSVR) is oriented approximately E-W in its western part called the Zhenbei-Huangyan seamount chain. Where is the extinct spreading ridge (ESR) of the East Sub-basin located? beneath the PSVR (Li et al., 2014)? Or intersecting with the PSVR by N055° orientation (Sibuet et al., submitted)? A three-dimensional Ocean Bottom Seismometer (OBS) survey covered both the central extinct spreading ridge and the Zhenbei-Huangyan seamount chain, the IODP Site U1431 (Li et al., 2014) being located just north of the chain. The results of this experiment will provide the essential information to understand the emplacement of the PSVR within the previously formed oceanic crust. The comprehensive seismic record sections of 39 OBSs are of high quality and show clear and reliable P-wave seismic phases, such as Pg, Pn and PmP. These seismic arrivals provide strong constrains for modeling the detailed three-dimensional velocity structure. We will show that the crust is oceanic on each side of the Zhenbei-Huangyan seamount chain, where is the location of the ESR and what is the genetic relationship between the magma chambers and the overlying Zhenbei-Huangyan seamount chain. We suggest that the large thickness of the upper crust is possibly due to volcanic extrusions and the thickened lower crust to magmatic underplating. Combining previous geochemical study of PSVR outcropping samples, the formation mechanism of the seamount chain might be explained by a buoyancy decompression melting mechanism (Castillo et al., 2010). This research was granted by the Natural Science Foundation of China (91028002, 91428204, 41176053). ReferencesSibuet J.-C., Yeh Y.-C. and Lee C.-S., 2015 submitted. Geodynamics of the South China Sea: A review with emphasis on solved and unsolved questions. Tectonophysics. Li, C. F., et al. 2014. Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349. Geochemistry

  19. The Dependency of Probabilistic Tsunami Hazard Assessment on Magnitude Limits of Seismic Sources in the South China Sea and Adjoining Basins

    Science.gov (United States)

    Li, Hongwei; Yuan, Ye; Xu, Zhiguo; Wang, Zongchen; Wang, Juncheng; Wang, Peitao; Gao, Yi; Hou, Jingming; Shan, Di

    2016-08-01

    The South China Sea (SCS) and its adjacent small basins including Sulu Sea and Celebes Sea are commonly identified as tsunami-prone region by its historical records on seismicity and tsunamis. However, quantification of tsunami hazard in the SCS region remained an intractable issue due to highly complex tectonic setting and multiple seismic sources within and surrounding this area. Probabilistic Tsunami Hazard Assessment (PTHA) is performed in the present study to evaluate tsunami hazard in the SCS region based on a brief review on seismological and tsunami records. 5 regional and local potential tsunami sources are tentatively identified, and earthquake catalogs are generated using Monte Carlo simulation following the Tapered Gutenberg-Richter relationship for each zone. Considering a lack of consensus on magnitude upper bound on each seismic source, as well as its critical role in PTHA, the major concern of the present study is to define the upper and lower limits of tsunami hazard in the SCS region comprehensively by adopting different corner magnitudes that could be derived by multiple principles and approaches, including TGR regression of historical catalog, fault-length scaling, tectonic and seismic moment balance, and repetition of historical largest event. The results show that tsunami hazard in the SCS and adjoining basins is subject to large variations when adopting different corner magnitudes, with the upper bounds 2-6 times of the lower. The probabilistic tsunami hazard maps for specified return periods reveal much higher threat from Cotabato Trench and Sulawesi Trench in the Celebes Sea, whereas tsunami hazard received by the coasts of the SCS and Sulu Sea is relatively moderate, yet non-negligible. By combining empirical method with numerical study of historical tsunami events, the present PTHA results are tentatively validated. The correspondence lends confidence to our study. Considering the proximity of major sources to population-laden cities

  20. The eddy-mean flow interaction and the intrusion of western boundary current into the South China Sea type basin in an idealized model

    Science.gov (United States)

    Zhong, Linhao

    2016-04-01

    In this paper, an ideal model on the role of mesoscale eddies in the Kuroshio intruding into the South China Sea (SCS) is developed, which represents the northwestern Pacific and the SCS by two rectangle basins connected by a gap. In the case of only considering intrinsic ocean variability, a time-dependent western boundary current (WBC) driven by steady wind is modeled under both eddy-resolving and non-eddy-resolving resolutions. Almost all simulated WBC intrudes into the adjacent sea in the form of loop current with multiple-state transitions and eddy-shedding process, which has aperiodic variations on intraseasonal or interannual scales, determined by the eddy-induced WBC variation. For the parameters considered in this paper, the WBC intrusion exhibits a 30~90-day cycle in the presence of the subgrid-scale eddy forcing (SSEF), but a 300~500-day cycle in the absence of SSEF. Moreover, the roles of the resolved (grid-scale) and unresolved (subgrid-scale) eddies in the WBC intrusion are studied. It is found that the unresolved eddy-flow interaction strongly regulates the WBC intrusion through the PV forcing induced by shear flows and baroclinic processes. But the resolved eddy forcing, which is dominated by the eddy-eddy interaction solely through baroclinic processes, shows weak correlation to the WBC intrusion. The associated eddy-induced PV exchange between the two basins is mainly accomplished by isopycnal-thickness eddy fluxes, particularly by the cross-front PV fluxes due to the unresolved eddy. And the unresolved eddy-flow interaction, as well as resolved and unresolved eddy-eddy interactions, mainly governs the PV transport for the WBC intrusion.

  1. Basin-wide distribution of phytoplankton lipids in the South China Sea during intermonsoon seasons: Influence by nutrient and physical dynamics

    Science.gov (United States)

    Dong, Liang; Li, Li; Li, Qianyu; Liu, Jie; Chen, Yuxing; He, Juan; Wang, Hui

    2015-12-01

    Four algal biomarkers, brassicasterol, C30-diol/keto-ol, dinosterol and C37-alkenone, representing diatoms, estigmatophytes, dinoflagellates and coccolithophorids, respectively, were detected in samples collected during two South China Sea cruises to study the modern phytoplankton community structure in the region. For the first time, the basin-wide distribution of these phytoplankton algal biomarkers in the sea surface water during two intermonsoon seasons (spring 2010 and autumn 2011) is documented and charted. Generally, the abundance of the biomass is higher in spring than autumn, with high productivity mostly in the regions of Pearl River estuary, off Palawan and around the Luzon Strait, showing the abundance order: diatoms>estigmatophytes>dinoflagellates>coccolithophorids. We run both redundancy analysis (RDA) and SPSS correlation analysis to interpret the relationship between individual groups and environmental variables. The results indicate that temperature and salinity play a dominant role in controlling the distribution of phytoplankton in these intermonsoon seasons, followed by nitrate playing a secondary role. Our biomarker survey provides important reference data for interpreting paleo-productivity in the geological records in the SCS.

  2. Structure and sediment budget of Yinggehai-Song Hong basin, South China Sea: Implications for Cenozoic tectonics and river basin reorganization in Southeast Asia

    Science.gov (United States)

    Lei, Chao; Ren, Jianye; Sternai, Pietro; Fox, Matthew; Willett, Sean; Xie, Xinong; Clift, Peter D.; Liao, Jihua; Wang, Zhengfeng

    2015-08-01

    The temporal link between offshore stratigraphy and onshore topography is of key importance for understanding the long-term surface evolution of continental margins. Here we present a grid of regional, high-quality reflection seismic and well data to characterize the basin structure. We identify fast subsidence of the basin basement and a lack of brittle faulting of the offshore Red River fault in the Yinggehai-Song Hong basin since 5.5 Ma, despite dextral strike-slip movement on the onshore Red River fault. We calculate the upper-crustal, whole-crustal, and whole-lithospheric stretching factors for the Yinggehai-Song Hong basin, which show that the overall extension observed in the upper crust is substantially less than that observed for the whole crust or whole lithosphere. We suggest that fast basement subsidence after 5.5 Ma may arise from crustal to lithospheric stretching by the regional dynamic lower crustal/mantle flow originated by collision between India-Eurasia and Indian oceanic subduction below the Eurasian margin. In addition, we present a basin wide sediment budget in the Yinggehai-Song Hong basin to reconstruct the sedimentary flux from the Red River drainage constrained by high-resolution age and seismic stratigraphic data. The sediment accumulation rates show a sharp increase at 5.5 Ma, which suggests enhanced onshore erosion rates despite a slowing of tectonic processes. This high sediment supply filled the accommodation space produced by the fast subsidence since 5.5 Ma. Our data further highlight two prominent sharp decreases of the sediment accumulation at 23.3 Ma and 12.5 Ma, which could reflect a loss of drainage area following headwater capture from the Paleo-Red River. However, the low accumulation rate at 12.5 Ma also correlates with drier and therefore less erosive climatic conditions.

  3. Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance

    Science.gov (United States)

    He, Enyuan; Zhao, Minghui; Qiu, Xuelin; Sibuet, Jean-Claude; Wang, Jian; Zhang, Jiazheng

    2016-05-01

    The 140-km wide last phase of opening of the South China Sea (SCS) corresponds to a N145° direction of spreading with rift features identified on swath bathymetric data trending N055° (Sibuet et al., 2016). These N055° seafloor spreading features of the East Sub-basin are cut across by a post-spreading volcanic ridge oriented approximately E-W in its western part (Zhenbei-Huangyan seamounts chain). The knowledge of the deep crustal structure beneath this volcanic ridge is essential to elucidate not only the formation and tectonic evolution of the SCS, but also the mechanism of emplacement of the post-spreading magmatism. We use air-gun shots recorded by ocean bottom seismometers to image the deep crustal structure along the N-S oriented G8G0 seismic profile, which is perpendicular to the Zhenbei-Huangyan seamounts chain but located in between the Zhenbei and Huangyan seamounts, where topographic changes are minimum. The velocity structure presents obvious lateral variations. The crust north and south of the Zhenbei-Huangyan seamounts chain is ca. 4-6 km in thickness and velocities are largely comparable with those of normal oceanic crust of Atlantic type. To the south, the Jixiang seamount with a 7.2-km thick crust, seems to be a tiny post-spreading volcanic seamount intruded along the former extinct spreading ridge axis. In the central part, a 1.5-km thick low velocity zone (3.3-3.7 km/s) in the uppermost crust is explained by the presence of extrusive rocks intercalated with thin sedimentary layers as those drilled at IODP Site U1431. Both the Jixiang seamount and the Zhenbei-Huangyan seamounts chain started to form by the intrusion of decompressive melt resulting from the N-S post-spreading phase of extension and intruded through the already formed oceanic crust. The Jixiang seamount probably formed before the emplacement of the E-W post-spreading seamounts chain.

  4. 南沙海域礼乐盆地沉积过程和演化%Depositional Process and Evolution of Liyue Basin in Southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    李鹏春; 赵中贤; 张翠梅; 谢辉; 陈广浩

    2011-01-01

    The evolution of rift-drift-subsidence can usually be illuminated by sedimental style, subsidence history and structural style, so it's possible to understand basin evolution through analysis of depositional process and coupling tectonic-sedimentary. In this paper, infill stratigraphy, subsidence history and structural characteristics are analyzed. The results show that Liyue basin is characterized by typical "tow-layer" structural pattern, which is separated by a regional breakup unconformity (T60). The horsts and grabens are in low basin overlain by upper depressions of the Neogene. And the half-grabens characterized by asymmetric wedge-shape are bounded by both normal faults and large-scale listric faults, which controlled the sedimentary cy cles. The subsidence method is mainly tectonic subsidence before 23. 8 Ma but is thermal subsidence after Late Oligocene. There were three regional subsidence episodes, and each subsidence rate was from slow to fast. Liyue basin is primarily composed of three regressive cycles of rift infilling influenced by regional tectonic, which correspond to three stages of basin development. The first stage, characterized by extensional stress, is related to early rift development from approximately 45 Ma until Early Oligocene. Featured by both extension and strike-slip stress, the second is associated with rift-drift development from initiation of sea floor spreading in South China Sea at 30 Ma until the end of sea floor spreading at Middle Miocene. And the third is late post-rift subsidence from approximately 16 Ma until 5. 5 Ma, which is controlled by transpressive stress field.%礼乐盆地所经历的张裂-漂移-碰撞沉降构造历史,在沉积物沉积样式、沉降历史及断裂构造样式中均有反映,因此,分析盆地沉积过程及其与构造的耦合关系可揭示其演化过程.通过对礼乐盆地沉积充填过程、沉降方式及构造特征的分析,认为礼乐盆地具双层结构模式特征,以T60

  5. Evaluation of abundant hydrocarbon-generation depressions in the deepwater area of Qiongdongnan Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Zhen; SUN Zhipeng; WANG Zisong; ZHANG Wei; LI Tingan; HE Weijun; LI Fengxia

    2016-01-01

    It has been confirmed that the key source rocks of Qiongdongnan Basin are associated with the Yacheng Formation, which was deposited in a transitional marine-continental environment. Because the distribution and evolution patterns of the source rocks in the major depressions are different, it is important to determine the most abundant hydrocarbon-generation depressions in terms of exploration effectiveness. Based on an analysis of organic matter characteristics of the source rocks, in combination with drilling data and seismic data, this paper establishes a model to evaluate the hydrocarbon-generation depressions in the deepwater area of Qiongdongnan Basin. First of all, by using the method of seismic-facies model analysis, the distribution of sedimentary facies was determined. Then, the sedimentary facies were correlated with the organic facies, and the distribution of organic facies was predicted. Meanwhile, the thickness of source rocks for all the depressions was calculated on the basis of a quantitative analysis of seismic velocity and lithology. The relationship between mudstone porosity and vitrinite reflectance (Ro) was used to predict the maturity of source rocks. Second, using the parameters such as thickness and maturity of source rocks, the quantity and intensity of gas generation for Yacheng and Lingshui Formations were calculated. Finally, in combination with the identified hydrocarbon resources, the quantity and intensity of gas generation were used as a guide to establish an evaluation standard for hydrocarbon-generation depressions, which was optimized for the main depressions in the Central Depression Belt. It is proposed that Lingshui, Ledong, Baodao and Changchang Depressions are the most abundant hydrocarbon depressions, whilst Songnan and Beijiao Depressions are rich hydrocarbon depressions. Such an evaluation procedure is beneficial to the next stage of exploration in the deep-water area of Qiongdongnan Basin.

  6. Tectonic Evolution of China and Its Control over Oil Basins

    Institute of Scientific and Technical Information of China (English)

    Wang Hongzhen; Li Sitian

    2004-01-01

    This paper is a brief review of the tectonic frame and crustal evolution of China and their control over the oil basins. China is subdivided into three regions by the Hercynian Ertix-Almantai (EACZ) and Hegenshan (HGCZ) convergent zones in the north, and the Indosinian Muztagh-Maqen (MMCZ) and the Fengxiang-Shucheng (FSCZ) convergent zones in the south. The northern region represents the southern marginal tract of the Siberian platform. The middle region comprises the Sino-Korea (SKP), Tarim (TAP) platforms and surrounding Paleozoic orogenic belts. The southern region includes the Yangtze platform (YZP), the Cathaysia (CTA) paleocontinent and the Caledonides between them in the eastern part, and the Qinghai-Tibet plateau composed of the Gondwana-affiliated massifs and Meso- and Cenozoic orogenic belts in the western part. The tectonic evolutions of China are described in three stages: Jinningian and pre-Jinningian, Caledonian to Indosinian, and post-Indosinian. Profound changes occurred at the end of Jinningian (ca. 830 Ma) and the Indosinian (ca. 210 Ma) tectonic epochs, which had exerted important influence on the formation of different types of basins. The oil basins distribute in four belts in China, the large superimposed basins ranging from Paleozoic to Cenozoic (Tarim and Junggar) in the western belt, the large superimposed basins ranging from Paleozoic to Mesozoic (Ordos and Sichuan) in the central belt, the extensional rift basins including the Cretaceous rift basins (Songliao) and the Cenozoic basin (Bohaiwan) in the eastern belt, and the Cenozoic marginal basins in the easternmost belt in offshore region. The tectonic control over the oil basins consists mainly in three aspects: the nature of the basin basement, the coupling processes of basin and orogen due to the plates interaction, and the mantle dynamics, notably the mantle upwelling resulting in crustal and lithospheric thinning beneath the oil basins.

  7. UNUSUAL DISTRIBUTION OF TRITERPANE AND STERANE TERRESTRIAL BIOMARKERS IN YACHENG CONDENSATES FROM YING-QIONG BASINS, SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    周毅; 盛国英; 傅家膜; 耿安松; 陈军红; 张启明; 潘贤庄; 黄保家

    2002-01-01

    The condensates from the Yacheng Gas Field, Ying-Qiong Basins, have unusual chemical characteristics, with distribution dominated by terpanes and steranes derived from higher-plants. Pr/Ph ratios (6-11) are very high. Drimane, cadinanes and homocadinanes exist in high concentration. Anomalously abundant 18α(H)-oleanane and remarkably abundant bicadinanes are present in Yacheng condensates, while 17α(H)-hopanes are in extremely low concentration. Taraxastaneand significantly abundant 17α(H)-diahopanes occur in the condensates. In addition, a number of C29 and C30 unknown pentacyclic triterpanes were monitored in the condensates, some of which are abundant. The unknown compounds may be terrestrial biomarkers or their occurrence may suggest a sub-oxic (dyacrobic) clay-rich depositional environment. C29 homologues are relatively predominant in regularand rearranged steranes. The concentration of diasteranes is markedly higher than that of regular steranes. The characteristics of Yacheng condensates are indicative of terrestrial source input. Based on condensate-condensate and condensate-rock correlations, combined with results of studies on sedimentary facies. Yacheng condensates may be sourced from Yacheng and Lingshui Formations in the Qiongdongnan Basin. The maturity of Yacheng condensate is relatively high, at late oil window stage (corresponding to 0.9%-1.3% R0), based on sterane and terpane maturity parameters.``

  8. Unusual distribution of triterpane and sterane terrestrial biomarkers in yacheng condensates from Ying-Qiong basins, South China sea

    Science.gov (United States)

    Zhou, Yi; Sheng, Guo-Ying; Fu, Jia-Mo; Geng, An-Song; Chen, Jun-Heng; Zhang, Qi-Ming; Pan, Xian-Zhuang; Huang, Bao-Jia

    2002-06-01

    The condensates from the Yacheng Gas Field, Ying-Qiong Basins, have unusual chemical characteristics, with distribution dominated by terpanes and steranes derived from higher-plants. Pr/Ph ratios (6 11) are very high. Drimane, cadinanes and homocadinanes exist in high concentration. Anomalously abundant 18α(H)-oleanane and remarkably abundant bicadinanes are present in Yacheng condensates, while 17α(H)-hopanes are in extremely low concentration. Taraxastane and significantly abundant 17α(H)-diahopanes occur in the condensates. In addition, a number of C29 and C30 unknown pentacyclic triterpanes were monitored in the condensates, some of which are abundant. The unknown compounds may be terrestrial biomarkers or their occurrence may suggest a sub-oxic (dyacrobic) clay-rich depositional environment. C29 homologues are relatively predominant in regular and rearranged steranes. The concentration of diasteranes is markedly higher than that of regular steranes. The characteristics of Yacheng condensates are indicative of terrestrial source input. Based on condensate-condensate and condensate-rock correlations, combined with results of studies on sedimentary facies. Yacheng condensates may be sourced from Yacheng and Lingshui Formations in the Qiongdongnan Basin. The maturity of Yacheng condensate is relatively high, at late oil window stage (corresponding to 0.9% 1.3% R0), based on sterane and terpane maturity parameters.

  9. Characteristics of Oil and Gas Accumulation in Yong'an-Meitai Area of the Fushan Depression, Beibuwan Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    Li Meijun; Wang Tieguan; Liu Ju; Zhang Meizhu; Lu Hong; Ma Qinglin; Gao Lihui

    2007-01-01

    The Yong'an-Meitai area is the focus of the present exploration in the Fushan Depression, Beibuwan Basin,South China Sea. All oils from this area are geochemically characterized by higher Pr/Ph ratio, higher proportion of heavy molecular weight hydrocarbons, and higher proportion of C29 regular steranes, which indicate that the organic matter of source rocks might have been deposited in an oxidizing palaeoenvironment and be dominated by higher plant organic matter input. The oil from E3w2 (the second member of Weizhou Fm. of the Oligocene) has a much higher density,relatively higher Pr/nC17 and Ph/nC18 ratios, and a "UCM-unresolved complex mixture" on gas chromatograms, which indicate that it has been slightly biodegraded. CPI and other terpane and sterane isomer ratios suggest they are all mature oils. The timing of oil charging in E3w2 and E2l1 (the first member of the Liushagang Fm. of the Eocene) determined by the homogenization temperatures of fluid inclusions and thermal evolution history are from 9-3 Ma and 8-3 Ma,respectively. Thus, the interpretation of E3w2 as a secondary reservoir is unlikely. The timing of oil charging is later than that of hydrocarbon generating and expulsion of Liushagang Fm. source rocks and trap formation, which is favorable for oil accumulation in this area. All molecular parameters that are used for tracing oil filling direction decrease with shallower burial depth, which suggests vertical oil migration. The widely occurring faults that penetrate through the source rocks of the Liushagang Fm. may serve as a fine oil charging conduit.

  10. CFD simulation on the generation of turbidites in deepwater areas:a case study of turbidity current processes in Qiongdongnan Basin, northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    JIANG Tao; ZHANG Yingzhao; TANG Sulin; ZHANG Daojun; ZUO Qianmei; LIN Weiren; WANG Yahui; SUN Hui; WANG Bo

    2014-01-01

    Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world’s most important hydrocarbon reservoirs. Several boreholes in the Qiongdongnan Basin, the north-western South China Sea, have recently revealed turbidity current deposits as significant hydrocarbon res-ervoirs. However, there are some arguments for the potential provenances. To solve this problem, it is es-sential to delineate their sedimentary processes as well as to evaluate their qualities as reservoir. Numerical simulations have been developed rapidly over the last several years, offering insights into turbidity current behaviors, as geologically significant turbidity currents are difficult to directly investigate due to their large scale and often destructive nature. Combined with the interpretation of the turbidity system based on high-resolution 3D seismic data, the paleotophography is acquired via a back-stripping seismic profile integrated with a borehole, i.e., Well A, in the western Qiongdongnan Basin; then a numerical model is built on the basis of this back-stripped profile. After defining the various turbidity current initial boundary conditions, includ-ing grain size, velocity and sediment concentration, the structures and behaviors of turbidity currents are investigated via numerical simulation software ANSYS FLUENT. Finally, the simulated turbidity deposits are compared with the interpreted sedimentary bodies based on 3D seismic data and the potential provenances of the revealed turbidites by Well A are discussed in details. The simulation results indicate that a sedimen-tary body develops far away from its source with an average grain size of 0.1 mm, i.e., sand-size sediment. Taking into account the location and orientation of the simulated seismic line, the consistence between normal forward simulation results and the revealed cores

  11. Mesozoic-Cenozoic Basin Features and Evolution of Southeast China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Late Triassic to Paleogene (T3-E) basin occupies an area of 143100 km2, being the sixth area of the whole of SE China; the total area of synchronous granitoid is about 127300 km2; it provides a key for understanding the tectonic evolution of South China. From a new 1:1500000 geological map of the Mesozoic-Cenozoic basins of SE China, combined with analysis of geometrical and petrological features, some new insights of basin tectonics are obtained. Advances include petrotectonic assemblages,basin classification of geodynamics, geometric features, relations of basin and range. According to basin-forming geodynamical mechanisms, the Mesozoic-Cenozoic basin of SE China can be divided into three types, namely: 1) para-foreland basin formed from Late Triassic to Early Jurassic (T3-J1)under compressional conditions; 2) rift basins formed during the Middle Jurassic (J2) under a strongly extensional setting; and 3) a faulted depression formed during Early Cretaceous to Paleogene (K1-E)under back-arc extension action. From the rock assemblages of the basin, the faulted depression can be subdivided into a volcanic-sedimentary type formed mainly during the Early Cretaceous (K1) and a red-bed type formed from Late Cretaceous to Paleogene (K2-E). Statistical data suggest that the area of all para-foreland basins (T3-J1) is 15120 km2, one of rift basins (J2) occupies 4640 km2, and all faulted depressions equal to 124330 km2 including the K2-E red-bed basins of 37850 km2. The Early Mesozoic(T3-J1) basin and granite were mostly co-generated under a post-collision compression background,while the basins from Middle Jurassic to Paleogene (J2-E) were mainly constrained by regional extensional tectonics. Three geological and geographical zones were surveyed, namely: 1) the Wuyishan separating zone of paleogeography and climate from Middle Jurassic to Tertiary; 2) the Middle Jurassic rift zone; and 3) the Ganjiang separating zone of Late Mesozoic volcanism. Three types of basin

  12. Study on Sequence Stratigraphy of Zhujiang and Zhuhai Formations, Zhu Ⅲ Subbasin, Pearl River Mouth Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The early Miocene in the Zhu Ⅲ subbasin, the Pearl River Mouth basin, includes two formations—Zhujiang and Zhuhai. There are 8 third-order sequences, S1, S2, S3, S4, S5, S6, S7 and S8 from the bottom of Zhuhai to the top of Zhujiang in these two formations. There are only one transgressive systems tract (TST) and one highstand systems tract (HST) in each sequence because the whole Zhu Ⅲ subbasin was located updip the shelf break during sequence deposition. The boundaries and maximum flooding surfaces (mfs) are in good response to both gamma and acoustic log curves in the study area. In seismic profile 1249, sediments obviously onlap over the unconformity (SB0, the bottom of Zhuhai Fm), SB1 and SB2, but obviously over only SB2 in seismic profile 1283 since the well-developed faults in the subbasin. The sand bodies with high porosity and permeability for petroleum migration and accumulation had been reworked by tidal currents before their burial. Hence, the tidal influenced parasequence sets occur both in TST and HST. Through detailed analysis, the sand bodies in TST are more favorable for petroleum to migrate and accumulate than those in HST.

  13. Cretaceous Phytoplankton Assemblages from Songke Core-1, North and South (SK-1, N and S) of Songliao Basin, Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yiyi; BAO Lina

    2009-01-01

    Cretaceous phytoplankton from the newly completed core hole (SK-1, N&S) in the central Songliao Basin was studied. The target interval is from the upper Quantou Formation of Upper Cretaceous to Mingshui Formation. Twelve genera of dinoflagellates, six of acritarcha and three of chlorophyta were identified in 588 samples from the 2300-m deep core. Ten phytoplankton assemblages have been classified: Tetranguladinium-Subtilisphaera.Botryococcus,Botryococcus-Pediastrum,Pediastrum,Dinogymniopsis-Chlamydophrella-Vesperopsis bifurcate, Dinogymniopsis minor-Balmula,Pediastrum-Botryococcus,Schizosporis-Campenia,Kiokansium-Dinogymniopsis.Botryococcus,Dinogymniopsis.Granodiscus.Filisphaeridium and Granodiscus. According to the findings mentioned above, the age of the upper Qantou Formation is Cenomanian, the Qingshankou Formation belongs to upper Cenomanian-Turonian, the Yaojia Formation to Coniancian-Santonian age, the Nenjiang Formation is of Campanian age, and Sifangtai-Mingshui formations are referred to Maastrichtian stage. The ecology of phytoplankton is closely related to water salinity. Each type of phytoplankton is within a certain living water mass whose evolution type reflects salinity change of the Songliao Lake. The assemblages from the SK-1 indicate that water salinity changes with the cycle of freshwater-slight brackish water-brackish water-slight brackish water-freshwater in the lake.

  14. A comprehensive assessment of agricultural intensification scenarios for the Dongting Lake basin in south-central China in 2030.

    Science.gov (United States)

    Yin, Guanyi; Liu, Liming; Chang, Xiao; Sun, Jin

    2016-07-01

    To explore the future of the material demand, pollutant emission, production, and arable land area surrounding the Dongting Lake basin, and to find a potential solution for agricultural development, this study assumes the following four agriculture intensification scenarios: the natural development scenario (ND), the production development scenario (PD), the moderate intensification scenario (MI), and the local resilience scenario (LR). The scenarios focus on different developmental patterns (natural development, short-term production growth, long-term sustainability, or self-sufficiency).The result shows to satisfy the food demand in 2030, and the production of crop and meat will be 26.96, 30.25, 28.05, and 16.27 × 10(6) t in ND, PD, MI, and LR, respectively; more than 1.78 × 10(6) ha of arable land is needed. Compared with the year 2012, the material input and pollutant output will increase by a maximum of 18.32 and 122.31 %, respectively. By classifying the environmental risk into four categories-greenhouse gas emission, air pollution, eutrophication, and ecotoxicity-the composite environmental risk index (CER) is calculated. The CER in PD was the highest, followed by that in ND, LR, and MI. Due to the production allocation within the 35 cities and counties, the spatial distribution of CER is more homogenous in PD and MI than in ND. The analysis of the scenarios reveals that through technological improvement and spatial allocation of agricultural production, scenario MI could be a potential direction for the government to design a sustainable agricultural-environmental system. PMID:27040549

  15. Dynamics Analysis of the Baiyun Sag in the Pearl River Mouth Basin,North of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    SUN Zhen; ZHONG Zhihong; ZHOU Di; PANG Xiong; HUANG Chunju; CHEN Changmin; HE Min; XU Hehua

    2008-01-01

    The Baiyun sag is a deep one developing on the slope of the Pearl River Mouth Basin.It occurs as a composite graben horizontally, and is composed of two sub-sags versus one low uplift.Vertically, the sedimentary architecture could be divided into three layers, i.e.the faulted layer on the bottom, the faulted-ductile stretching layer in the middle and the draping layer on the top. The main rifting stage of the sag is supposed to be characterized by ductile extension and thinning of the crust. The special deformation pattern is probably attributed to the fact that the Baiyun sag is located in the transfer zone of the pre-existing weak zone, which made the sag a strongly deformed area,characterized by the greatly thinned lithosphere and active magmatism. The highly rising mantle under the Baiyun sag should be an important mechanism responsible for the ductile deformation, which caused partial melting of the upper mantle. Upwelling to the upper crust and the sedimentary layers, the partial melting materials accommodated extensional strain and caused non.faulted vertical subsidence. Magma was collected under the transfer zone after the first stage of rifting, and transferred laterally in a direction perpendicular to the extension to the ENE and WSW parts of the sag and upwelled along the NW-trending basal faults, where WNW-trending shear faults developed in swarms. The faulting activity and sedimentation history of the Baiyun sag may have been affected by the ocean ridge jump around 24 Ma and the cessation of sea floor spreading around 16 Ma.

  16. Implementing Integrated River Basin Management in China

    Directory of Open Access Journals (Sweden)

    Lifeng Li

    2010-06-01

    Full Text Available This paper examines the role of the World Wildlife Fund for Nature China as policy entrepreneur in China. It illustrates the ways in which the World Wildlife Fund for Nature is active in promoting integrated river basin management in the Yangtze River basin and how the efforts at basin level are matched with the advice of the China Council for International Cooperation on Environment and Development task force on integrated river basin management to the national government of China. This article demonstrates that the World Wildlife Fund for Nature uses various strategies of different types to support a transition process towards integrated river basin management. Successful deployment of these strategies for change in environmental policy requires special skills, actions, and attitudes on the part of the policy entrepreneur, especially in China, where the government has a dominant role regarding water management and the position of policy entrepeneurs is delicate.

  17. China-South Africa Friendship Association Founded

    Institute of Scientific and Technical Information of China (English)

    Our Staff Reporter

    2008-01-01

    <正>On April 24, the founding ceremony of the China-South Africa Friendship Association (CSAFA) was held in Beijing on the occasion of the 10th anniversary of the establishment of diplomatic relations between China and South Africa.

  18. Sustainable Building in South China

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-11-15

    In view of sustainable building prioritized as a strategic sector by local government in South China, and the strong Dutch expertise and wide market recognition in this field especially the substantive presence of the Shanghai-based Dutch Sustainable Building Platform, the market in the South could be very potential and interesting to Dutch companies though strong competitors as well. An overview is given of the developments in the Chinese province Guangdong, Shenzhen city, Guangzhou City, Fujian Province, Guangxi Zhuang Autonomous Region, Hainan Province. Also information is given about important potential counterparts: China Merchant Group, Guangdong Energy Conservation Association, and potential areas for cooperation.

  19. South China Flooded

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Vehicles traverse a flooded street in Liuzhou, guangxi zhuang Autonomous Region, on May 19.heavy rainstorms repeatedly struck China this month, triggering floods, mudflows and landslides. hunan, guangdong and Jiangxi provinces and Chongqing Municipality were the worst hit.

  20. Climatic impacts of the Middle Route of the South-to-North Water Transfer Project over the Haihe River basin in North China simulated by a regional climate model

    Science.gov (United States)

    Zou, Jing; Zhan, Chesheng; Xie, Zhenghui; Qin, Peihua; Jiang, Shanshan

    2016-08-01

    The Middle Route of the South-to-North Water Transfer Project (MSWTP) was constructed to ease the water crisis over the North China Plain. In this study, we incorporated a water transfer scheme into the regional climate model RegCM4 and investigated the climatic impacts of the MSWTP over the Haihe River Basin in North China. Four 10 year simulation tests were conducted from 2001 to 2010 where different volumes of water were transferred. The results demonstrated that before the MSWTP was conducted the original groundwater exploitation and consumption over the Haihe River Basin led to wetting and cooling at the land surface with rapidly falling groundwater depth. The extra water input from the MSWTP slightly enhanced the wetting and cooling effects over the basin, as well as reduced the falling rate in the groundwater depth along the conveyance line. However, the weak climatic effects of the MSWTP were limited at a local scale and had no obvious interannual trends, because the transfer volume of the MSWTP was far lower than the total demand which has been conventionally satisfied through local water exploitation. In terms of seasonal variations, the greatest changes due to the MSWTP occurred in the summer for precipitation and soil moisture and in the spring for energy-related variables (heat fluxes and 2 m air temperature).

  1. Ordovician Cephalopod Biofacies of South China and Its Provincialization

    Institute of Scientific and Technical Information of China (English)

    Xiao Chuantao; Chen Zhiyong; Liu Li; He Youbin

    2006-01-01

    The research on biofacies and its provincialization is of important significance not only for the increasing of precision of stratigraphic subdivision and correlation in South China, the reconstruction of ancient environment and paleogeography and even the guiding of oil and gas exploration, but also for the study of paleobiogeogrphy and sea level changes of southern China in Ordovician. On the basis of the studies of the ecological characteristics of Ordovician cephalopods from South China, eighteen cephalopod biofacies are recognized and described:(1)Open platform Proterocameroceras biofacies;(2) Restricted platform Pseudoectenolites-Xiadongoceras biofacies;(3)Open platform Retroclitend oceras Pararetroclitendoceras biofacies;(4) Open platform Pronajaceras-Mamagouceras biofacies; (5) Shelf slope-basin Cyclostomiceras biofacies; (6) Open platform Cameroceras-Cyrtovaginoceras biofacies;(7) Open platform Coreanoceras-Manchuroceras biofacies; (8) Shelf slope-basin KaipingocerasKyminoceras biofacies; (9) Inner shelf Bathmoceras-Protocycloceras biofacies; (10) Middle shelf Dideroceras-Ancistroceras biofacies; ( 11 ) Deep-water shelf Lituites-Cyclolituites biofacies; (12) Stagnant basin Lituites-Trilacinoceras biofacies; (13) Deep-water basin Paraendoceras-Sactorthoceras biofacies; (14) Deep-water shelf Sinoceras-Michelinoceras-Disoceras biofacies; (15) Deep-water shelf Beloitoceras-Jiangshanoceras biofacies; (16) Deep-water shelf-basin Eurasiaticoceras biofacies; (17)Shelf-slope Jiangxiceras-Yushanoceras biofacies; (18) Deep-water basin Michelinoceras biofacies. The cephalopods of these biofacies, their ecological characteristics, and living conditions are elucidated in this article. The association law of cephalopod biofacies in time and space shows that there were three cephalopod biofacies provinces in South China during the Ordovician, I.e. , Yangtze biofacies province, East Guizhou (贵州)-West Hunan (湖南) biofacies province (mixed-type biofacies province

  2. China's Qaidam Basin Sensitive to Global Warming

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Chinese meteorologists recently pointed out that the temperatures in northwest China's resource-rich Qaidam Basin are rising faster than the rest of the country as a result of climate change.The rapid rise in temperatures is likely to increase the long-term frequency of droughts and farming pests in the basin to the northeast of the Qinghai-Tibet Plateau.Qaidam Basin covers 250,000 km2 in Qinghai Province and is known as resource-rich with salt lakes,petroleum,natural gas and other abundant mineral resources.

  3. Palinspastic reconstruction and geological evolution of Permian residual marine basins bordering China and Mongolia

    Institute of Scientific and Technical Information of China (English)

    Gen-Yao Wu

    2014-01-01

    One main feature of the tectono-paleogeographic evolution of the southern branch of the Paleo-Asian Ocean was that there developed residual marine basins in former backarc/forearc regions after the disappearance of oceanic crust. The paper illustrates the viewpoint taking the evolution of Dalandzadgad and Solonker oceanic basins as examples. The Dalandzadgad ocean subducted southwards during the Silurian-Devonian, created an intra-oceanic arc and a backarc basin in southern Mongolia. In addition, a continent marginal arc formed along the national boundary between China and Mongolia, the south of which was a backarc basin. The oceanic basin closed and arc-arc (continent) collision occurred dur-ing the early Early Permian, followed by two residual marine basins developing in the former backarc regions, named the South Gobi Basin in southern Mongolia and the Guaizihu Basin in western Inner Mongolia. The Solonker ocean subducted southwards and ifnally disappeared during the early Middle Permian. Afterwards, two residual marine basins occurred in northern China, the Zhesi Basin being situated in the former backarc region and the Wujiatun Basin in the former forearc region. The late Middle Permian was the most optimum period for the de-veloping residual marine basins, when they covered a vast area. The basin evolution differenti-ated during the early Late Permian, with a general trend of uplift in the east and of subsidence in the west. The Upper Permian in the South Gobi Basin was characterized by coal-bearing strata hosting economically valuable coal ifelds. A transgression invaded westwards and the Chandmani-Bayanleg Basin was created in southwest Mongolia during the middle-late stage of the Late Permian. Correspondingly, the coal formation entered a lfourishing time, with thick coal beds and sedimentary interbeds. All of these basins, namely, both the marine and non-marine residual basins, reversed and closed by the end of Permian.

  4. Palinspastic reconstruction and geological evolution of Permian residual marine basins bordering China and Mongolia

    Institute of Scientific and Technical Information of China (English)

    Gen-Yao; Wu

    2014-01-01

    One main feature of the tectono-paleogeographic evolution of the southern branch of the Paleo-Asian Ocean was that there developed residual marine basins in former backarc/forearc regions after the disappearance of oceanic crust.The paper illustrates the viewpoint taking the evolution of Dalandzadgad and Solonker oceanic basins as examples.The Dalandzadgad ocean subducted southwards during the Silurian-Devonian,created an intra-oceanic arc and a backarc basin in southern Mongolia.In addition,a continent marginal arc formed along the national boundary between China and Mongolia,the south of which was a backarc basin.The oceanic basin closed and arc-arc(continent) collision occurred during the early Early Permian,followed by two residual marine basins developing in the former backarc regions,named the South Gobi Basin in southern Mongolia and the Guaizihu Basin in western Inner Mongolia.The Solonker ocean subducted southwards and finally disappeared during the early Middle Permian.Afterwards,two residual marine basins occurred in northern China,the Zhesi Basin being situated in the former backarc region and the Wujiatun Basin in the former forearc region.The late Middle Permian was the most optimum period for the developing residual marine basins,when they covered a vast area.The basin evolution differentiated during the early Late Permian,with a general trend of uplift in the east and of subsidence in the west.The Upper Permian in the South Gobi Basin was characterized by coal-bearing strata hosting economically valuable coal fields.A transgression invaded westwards and the Chandmani-Bayanleg Basin was created in southwest Mongolia during the middle-late stage of the Late Permian.Correspondingly,the coal formation entered a flourishing time,with thick coal beds and sedimentary interbeds.All of these basins,namely,both the marine and nonmarine residual basins,reversed and closed by the end of Permian.

  5. South China Sea: Controversies And Solutions

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Disputes have recently broken out between China and some Southeast Asian countries and the United States in the South China Sea. The Beijing-based Economic Information Daily spoke to Liu Nanlai, a research fellow at the Institute of International Law under the Chinese Academy of Social Sciences, on the origin of the South China Sea issue and China’s position on it. Excerpts follow:

  6. Distribution of major hydrocarbon source rocks in the major oil-gas-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    LIU Luofu; ZHAO Suping; CHEN Lixin; HUO Hong

    2005-01-01

    The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Lüliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.

  7. Petroleum prospects of marine sequences in South China

    Institute of Scientific and Technical Information of China (English)

    Liqiao MA; Yong DONG; Xiaolong TU; Fengxia SUN; Jiufeng XIA; Lanying YANG

    2008-01-01

    The comprehensive study of the tectonicssequence stratigraphic-petroleum system shows that five sets of major regional and some local source rocks were developed in the tectonic evolution of South China,including the Lower Cambrian and Lower Silurian in the Caledonian cycle,the Middle Permian and Upper Permian in the Hercynian cycle,and the Lower Triassic in the Indo-Sinian cycle.Due to the inhomogeneous maturity of source rocks in this area,gas exploration would mainly be carried out in the Lower Paleozoic areas,while oil and gas exploration would be in the Upper Paleozoic ones.The reformation from the Indo-Sinian cycle to the Himalayan cycle exerted decisive influence on the hydrocarbon accumulation in the MesozoicCenozoic basin and marine sequences in southern China.The petroleum systems formed in the medium-late period of the superimposed basins are of the greatest potential.The distribution of primary and secondary oil-gas pools was mainly affected by favorable sedimentary facies,ancient uplift and slope.The comprehensive evaluation concluded that the focuses for petroleum exploration in the marine sequences of southern China will be in the superimposed basins along the margin of Yangtze landmass,the Subei-southern South Yellow Sea basin and the marine sequences preserved under the over-thrust nappe along the northern margin of the Jiangnan uplift.

  8. KUROSHIO INTRUSION INTO THE SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-hua; FAN Hai-mei; QU Yuan-yuan

    2006-01-01

    In this article, the circulation of the South China Sea (SCS), which is idealized as the rectangular basin with constant depth, is studied under Kuroshio boundary forces. Starting from the linearly quasi-geostrophic vorticity equation, the solution of the SCS circulation is given in the form of corrected Fourier series under proper boundary conditions. The results show that the intruded current flows westward and separates into the northward branch and the southward branch before arriving at the western boundary. The southward branch flows out of the SCS through the southwestern passage, at the same time, the induced cyclonic (anti-clockwise) ring almost occupies the middle and southern parts, and concomitant anti-cyclonic (clockwise) vortex appears between the cyclone and the western boundary. While the northward branch outflows through the northeastern passage, the anti-cyclonic (clockwise) ring is triggered at the northern part of the SCS. The above two vortexes are both intensified if the south-entering and the north-leaving current loop intrusion are superposed. The outer flow of the northern vortex flows westward, then northward, and then eastward, and it is very similar to the configuration of the SCS Warm Current (SCSWC) at the northern part of the SCS, thus, a kind of generating mechanism of the SCSWC is presented.

  9. Improved correction method for using passive air samplers to assess the distribution of PCNs in the Dongjiang River basin of the Pearl River Delta, South China

    Science.gov (United States)

    Wang, Yan; Li, Qilu; Xu, Yue; Luo, Chunling; Liu, Xiang; Li, Jun; Zhang, Gan

    2012-07-01

    An improved correction method was established using passive air samplers to assess the distributions of polychlorinated naphthalenes (PCNs) in the eastern Pearl River Delta, South China. This method was based on a joint correction that used the active air sampling rate and the addition of depuration compounds. As a correction factor, the depuration compounds' properties do not need to be similar to the target compounds. The total PCN air concentrations ranged from 6.4 to 832, with an average of 148 ± 201 pg m-3 in the study area, while the TEQ of the PCNs ranged from 1.2 × 10-4 to 2.6 × 10-2 pg m-3. High concentrations of PCNs were mostly observed in the highly industrialized areas. The PCN air levels were remarkably increased in winter compared with summer. Tri-CNs was the most dominant homologue group, while CN 24 was the most dominant congener. The high proportion of combustion-related PCNs suggests that the contribution of combustion sources to the PCN air burden has been significant recently in comparison with historical emissions.

  10. South China Sea: Disputes and Great Powers

    Institute of Scientific and Technical Information of China (English)

    Li Jinming

    2011-01-01

    In the South China Sea disputes, China has ample proof to claim sovereignty over the Xisha Islands (the Paracel Islands) and Nansha Islands (the Spratly Islands) while the claims of certain southeast Asian countries do not hold any water. The South China Sea disputes have their origins in the San Francisco Peace Treaty signed in 1951, the result of intervention by the United States and Great Britain in regional affairs. Even today, the United States has not discarded its Cold War mentality and continues to intervene in the South China Sea disputes. The only change in the United States' attitude is that it has changed its pretext for intervention from "containing Communist expansion" in the past to "preserving freedom of navigation in the South China Sea" in the present.

  11. Sustainable Energy in South China

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-04-15

    Eyeing on China's recent developments in its energy sector which result in increasing market opportunities, the Netherlands is willing to further strengthen bilateral cooperation in particular in the field of sustainable energy supply, not only on conventional energy but also new energy and renewable energy. This led to the signing of a MoU on energy cooperation between Minister Zhang Guo bao and his Dutch counterpart Minister Maria van der Hoeven on 9 September 2009, aiming at further deepening all-sided cooperation in energy-related areas. Not only the Dutch government, but also academic and research institutes, universities, branch organizations and companies in the Netherlands are aware of this potential market. Some of them are already active in China's domestic market with successful projects and impressive track records. In order to reinforce the competitiveness of Dutch companies and stimulate cooperation, the Consulate General of the Netherlands in Guangzhou is carrying out an investigation on sustainable energy in its resort, covering Guangdong, Guangxi, Fujian and Hainan Province. By investigating local market needs, the Consulate General has realized a number of interesting areas which the Dutch sector can offer its expertise and share experiences, such as energy comprehensive planning and management, eco-city projects, operation and maintenance of offshore wind power farms, deep-water engineering technologies and so on. The Consulate General is eager to pinpoint potential opportunities for the Dutch supply chain and promote Dutch expertise in South China. It is anticipated that the findings mentioned in this report can facilitate Dutch companies with market recognition, orientation and entry.

  12. Depositional architecture and evolution of inner shelf to shelf edge delta systems since the Late Oliocene and their respone to the tectonic and sea level change, Pear River Mouth Basin, northern South China Sea

    Science.gov (United States)

    Lin, Changsong; Zhang, Zhongtao; liu, Jingyan; Jiang, Jing

    2016-04-01

    The Pear River Mouth Basin is located in the northern continent margin of the South China Sea. Since the Late Oligocene, the long-term active fluvial systems (Paleo-Zhujiang) from the western basin margin bebouched into the northern continental margin of the South China Sea and formed widespread deltaic deposits in various depositional geomorphologies and tectonic settings. Based of integral analysys of abundant seismic, well logging and drilling core data, Depositional architecture and evolution of these delta systems and their respone to the tectonic and sea level change are documented in the study. There are two basic types of the delta systems which have been recognized: inner shelf delta deposited in shallow water enviroments and the outer shelf or shelf-edge delta systems occurred in deep water settings. The paleowater depths of these delta systems are around 30 to 80m (inner shelf delta) and 400-1000m (shelf-edge delta) estimated from the thickness (decompaction) of the delta front sequences. The study shows that the inner shelf delta systems are characterized by relatively thin delta forests (20-40m), numereous stacked distributary channel fills, relative coarse river mouth bar deposits and thin distal delta front or distal bar and prodelta deposits. In contrast, the outer shelf or shelf edge delta systems are characteristic of thick (300-800m) and steep (4-60) of deltaic clinoforms, which commonly display in 3D seismic profiles as "S" shape reflection. Large scale soft-sediment deformation structures, slump or debris flow deposits consisting mainly of soft-sediment deformed beds, blocks of sandstones and siltstones or mudstones widely developed in the delta front deposits. The shelf edge delta systems are typically associated with sandy turbidite fan deposits along the prodelta slopes, which may shift basinwards as the progradation of the delta systems. The delta systems underwent several regional cycles of evolution from inner shelf deltas to shelf edge

  13. China & South Africa in Full Swing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ China and South Africa will soon celebrate the 10th anniversary of their formal diplomatic relations establishment. On this special occasion, China's Foreign Trade conducted an interview with Mr. Alex Khumalo, the General Manager of Asia Pacific South Africa Chamber of Commerce (APSACC) Secretariat. Both countries have witnessed the growing friendship of two sides in the past decade, and more fruits are expected in the coming future.

  14. Eocene Podocarpium (Leguminosae from South China and its biogeographic implications

    Directory of Open Access Journals (Sweden)

    Qingqing eXu

    2015-11-01

    Full Text Available Podocarpium A. Braun ex Stizenberger is one of the most common legumes in the Neogene of Eurasia, including fossil fruits, seeds, leaves, and possible flower and pollen grains. This genus is not completely consistent with any extant genera according to gross morphological characters and poorly preserved cuticular structures reported in previous studies. The fossil pods collected from the coal-bearing series of the Changchang Basin of Hainan Island and Maoming Basin of Guangdong, South China, are examined by morphologically comparative work, with special reference to venation patterns and placental position. These distinctive features, as well as the ovule development of pods from different growing stages and the epidermal structure of the pods, as distinguished from previous records lead to the conclusion that these fossils can be recognized as a new species of Podocarpium, P. eocenicum sp. nov. This new discovery indicates that Podocarpium had arrived in South China by the Eocene. Investigation on the fossil records of this extinct genus shows that P. eocenicum is the earliest and lowest latitude fossil data. The possible occurrence pattern of this genus is revealed as follows: Podocarpium had distributed in the South China at least in the middle Eocene, and then migrated to Europe during the Oligocene; in the Miocene this genus reached its peak in Eurasia, spreading extensively across subtropical areas to warm temperate areas; finally, Podocarpium shrank rapidly and became extinct in Eurasia during the Pliocene.

  15. The South China sea margins: Implications for rifting contrasts

    Science.gov (United States)

    Hayes, D.E.; Nissen, S.S.

    2005-01-01

    Implications regarding spatially complex continental rifting, crustal extension, and the subsequent evolution to seafloor spreading are re-examined for the northern and southern-rifted margins of the South China Sea. Previous seismic studies have shown dramatic differences in the present-day crustal thicknesses as the manifestations of the strain experienced during the rifting of the margin of south China. Although the total crustal extension is presumed to be the same along the margin and adjacent ocean basin, the amount of continental crustal extension that occurred is much less along the east and central segments of the margin than along the western segment. This difference was accommodated by the early formation of oceanic crust (creating the present-day South China Sea basin) adjacent to the eastern margin segment while continued extension of continental crust was sustained to the west. Using the observed cross-sectional areas of extended continental crust derived from deep penetration seismics, two end-member models of varying rift zone widths and varying initial crustal thicknesses are qualitatively examined for three transects. Each model implies a time difference in the initiation of seafloor spreading inferred for different segments along the margin. The two models examined predict that the oceanic crust of the South China Sea basin toward the west did not begin forming until sometime between 6-12 my after its initial formation (???32 Ma) toward the east. These results are compatible with crustal age interpretations of marine magnetic anomalies. Assuming rifting symmetry with conjugate margin segments now residing along the southern portions of the South China Sea basin implies that the total width of the zone of rifting in the west was greater than in the east by about a factor of two. We suggest the most likely causes of the rifting differences were east-west variations in the rheology of the pre-rift crust and associated east-west variations in the

  16. The complexity of South China Sea kinematics

    Science.gov (United States)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  17. Provenance and sediment dispersal of the Triassic Yanchang Formation, southwest Ordos Basin, China, and its implications

    Science.gov (United States)

    Xie, Xiangyang

    2016-04-01

    The Ordos Basin in north central China records a transition from marine to non-marine deposition during the late Paleozoic to early Mesozoic. As a result, the northern and southern regions of the Ordos Basin show different tectonic histories and very distinctive sedimentation styles. Two deformation belts, the Qinling orogenic belt to the south and the Liupanshan thrust and fold belt to the west, controlled the structural evolution of the southern Ordos Basin during the early Mesozoic. Paleocurrent analysis, net-sand ratio maps, sandstone modal analysis, and U-Pb detrital zircon geochronology were used to document sediment sources and dispersal patterns of the Triassic Yanchang Formation in the southwest Ordos Basin. Paleocurrent measurements suggest that the sediments were mainly derived from the Liupanshan and the Qinling orogenic belts. Net-sand ratio maps show that several fan delta systems controlled sediment delivery in the south Ordos Basin. Both sandstone modal analysis and U-Pb detrital zircon geochronology suggest that the Yanchang Formation is locally sourced from both of the basin marginal deformation belts; the lower and middle sections are recycled Paleozoic sedimentary rocks mainly derived from the north Qinling orogenic belt, whereas for the upper section, the Qilian-Qaidam terranes and possibly the west Qinling orogenic belt began to shed sediments into the southwest Ordos Basin. Results have important implications for basin marginal tectonics and its controls on sedimentation of intracratonic basins in China and similar settings.

  18. GRACE captures basin mass dynamic changes in China based on a multi-basin inversion method

    Science.gov (United States)

    Yi, Shuang; Wang, Qiuyu; Sun, Wenke

    2016-04-01

    Complex landform, miscellaneous climate and enormous population have enriched China with geophysical phenomena ranging from water depletion in the underground to glaciers retreat on the high mountains and have aroused large scientific interests. This paper, utilizing gravity observations 2003-2014 from the Gravity Recovery and Climate Experiment (GRACE), intends to make a comprehensive estimation of mass status in 16 drainage basins in the whole region. We proposed a multi-basin inversion method, which is featured by resistance to the stripe noise and ability to alleviate signal attenuation due to truncation and smoothing of GRACE data. The results show both positive and negative trends: there is a tremendous mass accumulation spreading from the Tibetan plateau (12.2 ± 0.6 Gt/yr) to the Yangtze River (7.6 ± 1.3 Gt/yr), and further to the southeast coastal areas, which is suggested to involve an increase in the ground water storage, lake and reservoir water volume and likely materials flowed in by tectonic process; a mass loss is occurring in Huang-Huai-Hai-Liao River Basin (-10.5 ± 0.8 Gt/yr), as well as the Brahmaputra-Nujiang-Lancang River Basin (-15.0 ± 0.9 Gt/yr) and Tienshan Mountain (-4.1 ± 0.3 Gt/yr), which is a result of groundwater pumping and glacier melting. The groundwater depletion area is well consistent with the distribution of land subsidence in North China. In the end, we find intensified precipitation can alter the local water supply and GRACE is proficient to capture this dynamics, which could be instructive for the South-to-North Water Diversion - one China's giant hydrologic project.

  19. Petroleum Exploration of Craton Basins in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Craton basins are a significant petroliferous provenance. Having undergone multiple openclose tectonic cycles and strong reworking of the late Cenozoic tectonic movement, the craton basins in China are highly broken. This has resulted in multi-source and multiphase hydrocarbon generation and later hydrocarbon accumulation so that a complicated spatial assemblage of primary, paraprimary and secondary oil-gas pools has been formed. The primary factors controlling hydrocarbon accumulation include hydrocarbon-generating depressions, paleouplifts, paleoslopes, unconformity surfaces, paleo-karst, faults and fissure systems as well as the later conservation conditions. In consequence, the strategy of exploration for China's craton basins is to identify the effective source rocks, pay attention to the different effects of paleohighs and late reworking, enhance studies of the secondary storage space, attach importance to the exploration of lithologic oil-gas reservoirs and natural gas pools, and approach consciously from the secondary oil pools to the targets near the source rocks. At the same time, a complete system of technologies and techniques must be built up.

  20. Syn-Rift Subsidence Deficit of the Qiongdongnan Basin and the Synchronous Rapid Uplift of South Hainan Island: Some Clues on Surface Response to the Hainan Plume, NW South China Sea

    Science.gov (United States)

    Shi, X.

    2014-12-01

    Based on tomography, geochemical and petrological evidences, a mantle plume called Hainan Plume has been suggested lying under Hainan Island. Our recent studies on basin subsidence and surface topography indicated that there existed surface vertical motion response to the suggested mantle plume. Post-rift rapid subsidence in the Qiongdongnan basin, which lies south of Hainan Island, is well known and accepted phenomenon. A particular feature is that the rapid subsidence did not just follow the end of syn-rift phase at ~ 21 Ma, but began after a ~10 my relatively tectonic quiescence. Different tectonic processes have been proposed to account for this rapid subsidence event. However, all these proposed mechanisms just focus on the rapid subsidence episode since Late Miocene. Our details subsidence analyses show that its tectonic subsidence is of a two-stage anomalous character: the deficit subsidence at the end of the syn-rift phase and the well known post-rift rapid subsidence after 10.5 Ma. Numerical analyses show that the stretching factor βs based on syn-rift sequences is much less than the observed crustal stretching factor βc, and the present basement depth can be almost predictable if assuming that the lithosphere was thinned with stretching factor βc; The crustal thinning happened during the syn-rift phase (before 21 Ma), and a new rifting and lower crustal flow after 21 Ma were not supported, proposing further that the syn-rift subsidence is deficit. Our further analyses proposed that the syn-rift subsidence deficit might be caused by the dynamic support of the secondary plume, and the post-rift rapid subsidence might result from the losing support of the thermal source decaying, therefore occurred to compensate the subsidence deficit of the syn-rift phase. The cooling history of the southern Hainan deduced by low temperature chronometry data, also indicated there exist an uplift event in the Late Oligocene (Shi et al., 2011). All the samples show that

  1. 南海西北次海盆的磁条带重追踪及洋中脊分段性%The magnetic lineation identifications and segmentation of the northwestern sub-basin in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    张涛; 高金耀; 李家彪; 吴招才; 吴振利; 赵俐红; 杨春国; 沈中延; 周志远

    2012-01-01

    Since there is no valid deep sea drilling core, there are some debates about the opening age of the South China Sea (Nanhai). Owning to the small area, few magnetic polarity reversals and low magnetic anomalies amplitude of the northwestern sub-basin, the controversies about its opening age are very intense. The latest marine magnetic profiles which are closely spaced less than 10 km reveal the obvious magnetic lineation in the northwestern sub-basin. Constrained by newly measured ocean bottom seismic and multi-channel seismic data, we present a new identification to the latest marine magnetic profiles. According to the results of quantitative comparison, we prefer the northwestern sub-basin initially opened at 35.8 Ma (C16n, 2n), propagated to southwest at about 34. 7 Ma (C15) and all relict ridges ceased at the same time (33. 2 Ma, C13n). The full spreading rate is about 40~50 mm/a. The result implies the South China Sea was initially opened in the northwestern sub-basin and the eastern basin began to spread (about 30 Ma) after the cease of the northwestern sub-basin. The accurate and dense data give the great opportunity to study the segmentations with magnetic anomalies reducted to the pole and the inversed magnetization. Six segments and one obvious transform fault are revealed here and the segmentation is consistent with the crustal thickness variation based on OBS data. To the east of the transform fault, the main part of relict ridge includes four segments which are connected by non-transform offsets and each segment is about 30 km. To the west of the transform fault, one segment is about 50 km and another one is uncertain here. The variation of magnetization amplitude along each segment is correlated with corresponding segment length. Magnetization in the center of segments is lower than that of segments ends and its magnetic structure along spreading axis is similar to the slow-spreading mid-Atlantic ridge which also has similar full spreading rate.%由

  2. A Survey of Coral Reefs in South China Sea Completed

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ An investigation of coral reefs in South China Sea has recently completed by CAS scientists at South China Sea Institute of Oceanography (SCSIO) in Guangzhou. The compilation and analysis of the obtained data is now under way.

  3. South China Feels Acute Labor Shortage

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Pearl River Delta, with Guangzhou — the capital of Guangdong Province — as its nucleus, has for years been an economic powerhouse in China.Millions of surplus rural workers once flocked to the south China region to find jobs, but now the area is facing a crisis: many farmers-turned-laborers are shunning the Pearl River area and are moving instead to the Yangtze River Delta,

  4. Research on the dynamics of the South China Sea opening: Evidence from analogue modeling

    Institute of Scientific and Technical Information of China (English)

    SUN; Zhen; ZHOU; Di; ZHONG; Zhihong; XIA; Bin; QIU; Xuelin; ZENG; Zuoxun

    2006-01-01

    Independent of Indochina extrusion, the South China Sea experienced a process from passive continental rifting to marginal sea drifting. According to the fault patterns in the Beibu Gulf basin and the Pearl River Mouth basin, the continental rifting and early spreading stage from 32 to 26 Ma were controlled by extensional stress field, which shifted clockwise from southeastward to south southeastward. From 24 Ma on, the sea spread in NW-SE direction and ceased spreading at around 15.5 Ma. Integrated geological information with the assumption that the South China Sea developed along a pre-Cenozoic weakness zone, we did analogue experiments on the South China Sea evolution. Experiments revealed that the pre-existing weakness zone goes roughly along the uplift zone between the present Zhu-1 and Zhu-2 depression. The pre-existing weakness zone is composed of three segments trending NNE, roughly EW and NEE, respectively. The early opening of the South China Sea is accompanied with roughly 15° clockwise rotation, while the SE sub-sea basin opened with SE extension. Tinjar fault was the western boundary of the Nansha block (Dangerous Ground),while Lupar fault was the eastern boundary of the Indochina, NW-trending rift belt known as Zengmu basin developed between above two faults due to block divergent of Indochina from Nansha. In the experiment, transtensional flower structures along NW-trending faults are seen, and slight inversion occurs along some NE-dipping faults. The existence of rigid massifs changed the orientations of some faults and rift belt, and also led to deformation concentrate around the massifs. The rifting and drifting of the South China Sea might be caused by slab pull from the proto South China Sea subducting toward Borneo and/or mantle flow caused by India-Asia collision.

  5. Petroleum exploration potential in abyssal zone of Qiongdongnan Basin, South China Sea%南海琼东南盆地深水区油气勘探潜力

    Institute of Scientific and Technical Information of China (English)

    朱廷祥; 段铁军

    2012-01-01

    南海琼东南盆地经历了始新世的陆内断陷、渐新世的裂谷和中新世以来的被动陆缘坳陷等3个演化阶段,特别是在深水区形成了断陷期湖相、裂谷期海陆过渡相到海相及被动陆缘坳陷期海相等多套生烃物质;3期构造沉降作用伴随了3次高热流事件,利于烃源岩的成熟;多储集体类型、多套储盖组合,为油气富集提供了广阔的空间;多期构造运动,形成多种圈闭类型,利于油气聚集成藏.%The evolution of the Qiongdongnan Basin in the South China Sea can be divided into three stages including intracontinental rift during Eocene, rift during Oligocene, and passive continental margin depression ever since Miocene. Multiple sets of petroleum generating materials of different facies were deposited in abyssal zone. For example, lacustrine facies in the first stage, marine-continental and continental facies in the second stage, and marine facies in the third stage. Three high thermal fluid events took place during the three evolution stages, contributing to the maturation of source rocks. Multiple types of reservoir and multiple sets of reservoir - cap assemblage provided abundant room for the enrichment of petroleum. Various types of trap formed during stages of tectonic movements were favorable for accumulation.

  6. THE PRELIMINARY STUDY OF SEGMENTATION OF THE MID-OCEAN RIDGE IN SOUTHWEST SUB-BASIN OF THE SOUTH CHINA SEA%南海西南次海盆洋中脊分段特征

    Institute of Scientific and Technical Information of China (English)

    李细兵; 吴振利; 李家彪

    2013-01-01

    通过对南海西南次海盆的古洋中脊地貌、重力、磁力异常的分析,确定是一个带有中央裂谷性质的古扩张中心,其转换断层两侧分别在地貌、重力、磁力上表现出不同的特征.根据这些特征,沿古洋中脊识别出4条转换断层,对所有转换断层的性质进行了分析,特别对第4条转换断层的性质做了详细探讨,认为该转换断层是西南次海盆中大陆裂谷与洋壳相互演化的一个转换带,这可能意味着该转换带两侧地壳结构属性会有所不同.%According to the analysis of the geomorphology,gravity,magnetic data of the extinct mid-ocean ridge in southwest sub-basin of the South China Sea (SCS),a relict rifting center is found in the study area,of which the feature is similar to that of Atlantic mid-ocean ridge.Four transform faults are identified along the mid-ocean ridge in spatial location.Each of the transform faults shows distinct geophysical features compared with the others.The fourth one is specially discussed in details.It might be an important transition zone between the continental rifting and sea floor spreading,which implies a different crustal structure on both sides of the fault.

  7. Dominant factors in controlling marine gas pools in South China

    Institute of Scientific and Technical Information of China (English)

    XU Sihuang; W.Lynn Watney

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China,there develop four sets of regional and six sets of local source rocks,and ten sets of reservoir rocks.The occurrence of four main formation periods in association with five main reconstruction periods,results in a secondary origin for the most marine gas pools in South China.To improve the understanding of marine gas pools in South China with severely deformed geological background,the dominant control factors are discussed in this paper.The fluid sources,including the gas cracked from crude oil,the gas dissolved in water,the gas of inorganic origin,hydrocarbons generated during the second phase,and the mixed pool fluid source,were the most significant control factors of the types and the development stage of pools.The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale.Owing to the multiple periods of the pool formation and the reconstruction,the distribution of marine gas pools was complex both in space and in time,and the gas in the pools is heterogeneous.Pool elements,such as preservation conditions,traps and migration paths,and reservoir rocks and facies,also served as important control factors to marine gas pools in South China.Especially,the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale.According to several dominant control factors of a pool,the pool-controlling model can be constructed.As an example,the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up.

  8. Dominant factors in controlling marine gas pools in South China

    Science.gov (United States)

    Xu, S.; Watney, W.L.

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up. ?? Higher Education Press and Springer-Verlag 2007.

  9. LATEST DEVONIAN (FAMENNIAN TO EARLIEST CARBONIFEROUS (TOURNAISIAN BRACHIOPODS FROM THE BACHU FORMATION OF THE TARIM BASIN, XINJIANG PROVINCE, NORTHWEST CHINA

    Directory of Open Access Journals (Sweden)

    Z Q. CHEN

    1999-07-01

    Full Text Available Brachiopods are described from two horizons of the Bachu Formation from the Bachu area of the Tarim Basin, Xinjiang Province, northwest China. We assign the brachiopods from the basal Bachu Formation to late Famennian and correlate those from its upper part to the Eochoristites-Martiniella Assemblage of South China, of early Tournaisian age. The brachiopod fauna of the Bachu Formation exhibits strong generic and specific links with coeval South Chinese faunas, suggesting a close biogeographical affinity with the South China block. Eleven species are described, including one new species, Ptychomaletoechia bachuensis sp. nov. 

  10. From Basin Black Shales to Platform Carbonate Rocks: A Study on Sequence Stratigraphy for the Lower Cambrian of the Upper-Yangtze Region in South China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the Upper-Yangtze region, especially in Guizhou Province and its adjacent areas, the Lower Cambrian is well developed and is marked by a succession from black shales of the basin facies to carbonate rocks of the platform facies. The drowning event of the platform occurring at the turn from Sinian to Cambrian resulted in a set of black shales, i.e. the Niutitang Formation, which makes up the bottom part of the Lower Cambrian. With the shoaling of the sedimentary environment, a set of carbonate rocks, i.e. the Qingxudong Formation, was formed in the top part of the Lower Cambrian. Thus, the Lower Cambrian in the study area makes up one second-order sequence that can be further subdivided into five third-order sequences, and forms a regularly cyclic succession of transgression-regression. There is a regularly vertical stacking pattern for the third-order sequences in the second-order sequence. From bottom to top, the succession of the "CS (condensed section)+HST (high-stand system tract)" of the third-order sequences is changed into the succession of the "TST (transgressive system tract)+CS+HST". Correspondingly, the drowning-type sequence boundary is changed into the exposure-type one. Therefore, both the second-order and the third-order sequences have similar sedimentary-facies architectures. A concomitant with these temporal changes,the Lower Cambrian with a thickness of 1000 m that contains five third-order sequences is changed into a condensed succession that cannot identify third-order sequences toward the southeast with the deepening of the sedimentary environment. According to the elementary features of the third-order sequences, i.e. the regularity o sedimentary-facies successions in space and the synchronism of sedimentary-environment changes in time, the detailed division of the third-order sequences at main logged sections in different paleogeographical background becomes the basis to establish the sequence-stratigraphic framework that can demonstrate

  11. Geochemical environmental changes and dinosaur extinction during the Cretaceous-Paleogene (K/T) transition in the Nanxiong Basin, South China: Evidence from dinosaur eggshells

    Institute of Scientific and Technical Information of China (English)

    ZHAO ZiKui; MAO XueYing; CHAI ZhiFang; YANG GaoChuang; ZHANG FuCheng; YAN Zheng

    2009-01-01

    The complex patterns of trace elements including Ir and isotope distributions in the three K/T sections of the Nanxiong Basin prove the existence of two environmental events in the latest Cretaceous and earliest Paleocene. The first geochemical environmental event occurred at about 2 Ma prior to the K/T boundary interval, where the dinosaur diversity was hardly reduced, except that a number of patho-logical eggshells appeared. The second one was larger and occurred just at and near the Creta-ceous-Paleogene (K/T) boundary. The extinction of the dinosaurs spread out within 250 ka with major extinction beginning at the boundary interval. This is even later than their extinction in Montana, North America and in India. The cause of the dinosaur extinction may be the result of a complex multiple events brought about by the coincidence of global environment change marked by multiple Ir and δ18O anomalies, and environmental poisoning characterized by other trace elements derived from the local source. Successive short-and long-term conditions of geochemically induced environmental stress negatively affected the reproductive process and thus contributed to the extinction of the dinosaurs.

  12. Middle Miocene reworked turbidites in the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea margin: Processes, genesis, and implications

    Science.gov (United States)

    Gong, Chenglin; Wang, Yingmin; Zheng, Rongcai; Hernández-Molina, F. Javier; Li, Yun; Stow, Dorrik; Xu, Qiang; Brackenridge, Rachel E.

    2016-10-01

    Our understanding of reworked turbidites is still in its infancy, and their flow processes and genesis still remain understudied. Core data from the middle Miocene Zhujiang Formation in the Pearl River Mouth Basin allow us to differentiate reworked turbidites, yielding two main contributions. Firstly, reworked turbidites are distinguished from turbidites by the association of traction structures and tidal signatures, which occur in discrete units rather than forming a classic "Bouma Sequence" for turbidites. Sedimentological characteristics of reworked turbidites proposed here will help to obtain a robust set of diagnostic criteria for the recognition of deep-water non-turbidite deepwater units as reservoirs. Secondly, our results suggest that, in the down-slope direction, classic detritus carried in turbidity flows would synchronously be bidirectionally reworked by internal tides and waves, resulting in tidal signatures seen in the interpreted reworked turbidites. In the along-slope direction, upper parts of dilute turbidity currents would mix vertically with seawater, and muddy fines would be winnowed away by contour currents, whereas lower parts of dilute turbidity currents would probably drop their coarse particles, resulting in traction structures recognized in the documented reworked turbidites. Our work highlights the influence of bottom currents on the development and modification of turbidites and suggests that reworked turbidites were created by the combined action of down-slope transport and reworking and along-slope winnowing and sorting, helping to better understand flow processes and genesis of non-turbidite reservoirs with a great economic interest.

  13. 沙海槽前陆盆地热流变结构%Lithospheric Thermal-Rheological Structure of Nansha Trough Foreland Basin in South China Sea

    Institute of Scientific and Technical Information of China (English)

    马辉; 许鹤华; 施小斌; 陈爱华; 刘唐伟

    2011-01-01

    为了研究南沙海槽前陆盆地深部岩石圈的热力学性质,在前人所做的地质与地球物理研究工作的基础上,结合各种岩石热力学流变参数,采用有限元分析方法,计算了现今构造逆冲之后和中中新世一全新世逆冲过程活跃时两种状态下的深部岩石圈二维温度场和流变结构.模拟计算表明,南沙海槽前陆盆地地幔热流贡献达60%~70%,大地热流受深部地幔控制.逆冲推覆构造作用使盆地逆冲推覆带地表热流显著升高了 15%~25%,达到70~75 mW/m2.盆地沉积层温度在200℃以内,莫霍面温度420~500℃,地壳地温梯度25~30℃/km.盆地热岩石圈厚度为80 km左右,横向上变化幅度不大.南沙海槽前陆盆地深部岩石圈流变性质具有明显的分层特性,为典型的“三明治”结构.盆地岩石圈综合强度南南沙海槽向逆冲推覆带方向呈下降趋势,盆地力学岩石圈厚度50 km左右,有效弹性厚度为30~32 kn.通过模拟盆地深部岩石圈热流变结构,揭示了盆地深部岩石圈具有强地幔、弱地壳的流变学特征,表现为高强度块体.同时南沙海域地震活动与深部岩石圈热结构、热活动和岩石圈综合强度密切相关.地壳内热构造活动弱、岩石圈强度大可能是区域地震很少发生的重要原因.%In order to study the lithospheric thermodynamic properties of Nansha trough foreland basin, we simulate the deep lithosphere temperature field and rheological structure during the thrust faults tectonic activities from Middle Miocene to Hol-ocene and after thrusting (static) in the basin using the finite element method, based on previous studies of geological and geophysical data together with a variety of rock thermodynamic parameters. Simulation results indicate that heat flow contribution from mantle reaches 60% - 70% of surface heat flow which is controlled by deep mantle in Nansha trough foreland basin. Thrusting movements increase

  14. On the Origin of One Basin-Multiple Mountain Couplings in the Mesozoic-Cenozoic Basin-Range Area in Eastern North China

    Institute of Scientific and Technical Information of China (English)

    NIU Shuyin; SHAO Ji'an; HOU Quanlin; WANG Baode; XU Chuanshi

    2004-01-01

    The basin-range coupling relation is a leading subject of the modern geology. In geometry, relations of this type include couplings between stretched orogenic belt and down-faulted basin, compressional orogenic belt and foreland basin, strike-slip orogenic belt and strike-slip basin and so on. Fault chains are the key for these couplings and there are typical examples for all these cases. The North China down-faulted basin is coupled west with the Tathang uplift, east with the Jiao-Liao Mountains, north with the Yanshan orogenic belt and south with the Dabie orogenic belt,that is to say, the central down-faulted basin and the surrounding orogenic belts bear a coupling relation within a uniform dynamistic system. Study shows that the central down-faulted basin and the North China mantle sub-plume structure have a close relation during their formation. Owing to intensive mantle sub-plume uplifting, the bottom of the lithosphere suffered from resistance, which caused the lithosphere of the eastern North China to be heated, thinned and fault-depressed. Meanwhile, mantle rocks that were detached outwards in the shape of mushroom was dissected by surrounding ductile shearing zones, which lead to decompression and unloading to generate hypomagmas, and a series of mantle-branch structures were formed around the down-faulted basin. There is an obvious comparability among these mantle branch structures (orogenic belts), and they have basin-range coupling relations with the central down-faulted basins.

  15. Sedimentary Characteristics and Model of Gravity Flow Depositional System for the First Member of Upper Miocene Huangliu Formation in Dongfang Area, Yinggehai Basin, Northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Ming Sun; Hua Wang; Jihua Liao; Huajun Gan; Jun Xiao; Jinfeng Ren; Shue Zhao

    2014-01-01

    The gravity flow deposit were mainly developed in the lowstand systems tract (LST) of the first member of Upper Miocene Huangliu Formation (Ehl1) in Dongfang area, Yinggehai Basin, has become a valuable target for gas exploration and production. The gravity flow sedimentary character-istics of lithofacies associations, sedimentary texture, seismic facies and logging facies were described in detail on the basis of integrated analysis of cores, logging and seismic data. The sedimentary microfacies types composed of neritic sandbar, continental shelf mud, main channel, bifurcated or cross-cutting distributary channel, overspill, and natural levee are revealed under the constraint of high resolution sequence stratigraphic framework in the Ehl1. The gravity flow deposit system in the LST is divided into three evolution stages corresponding to periods of three parasequence sets. The gravity flow deposit was induced in the early LST, expanded rapidly in the middle LST and decreased slightly in the late LST. But its developing scale decreased sharply in the transgression systems tract (TST) and finally vanished in the highstand systems tract (HST). This spatial evolution rule is constrained by the integrated function of sediments supply of the Vietnam Blue River in the LST, the development of local gradient change in sea floor (micro-topography, i.e., flexure slope break), and the fall in relative sea lev-el. On the basics of the deep study of the coupling relationship among the three main control factors, the sedimentary model is established as an optimal component of “source-channel-sink” for shallow marine turbidite submarine fan.

  16. Organic geochemistry and coal petrology of Tertiary brown coal in the Zhoujing mine, Baise Basin, South China -4. Biomarker sources inferred from stable isotope compositions of individual compounds

    Energy Technology Data Exchange (ETDEWEB)

    Schoell, M.; Simoneit, B.R.T.; Wang, T.-G. (Chevron Petroleum Technology Co., La Habra, CA (United States))

    Carbon isotopic compositions of extractable compounds derived from higher land plants are with [+-]2[per thousand] of the bulk coal ([delta][sup 13]C -27.0[per thousand]) from Baise Basin. This data suggests that either similar species contributed these compounds or that the plants from which this coal was formed imposed similar biosynthetic fractionations. The terpenoid hydrocarbons form two isotopically distinct groups: the diterpenoids ([delta][sup 13]C 2.50 [+-] 1.4[per thousand]) and the sesquiterpenoids ([delta][sup 13]C 25.9 [+-] 1.5[per thousand]) are on average 1-2[per thousand] enriched in [sup 13]C compared to the bulk coal, whereas the oleanane-ursane-lupane derivatives ([delta][sup 13]C 29.0 [+-] 0.8[per thousand]) are on average 1-2[per thousand] depleted in [sup 13]C compared to the bulk coal. The n-alkanes, ranging from C[sub 15] to C[sub 35], have a mean [delta][sup 13]C value of -32.4 [+-] 0.6[per thousand], whereby averages for the C[sub 17]-C[sub 22] and C[sub 23]-C[sub 33] n-alkanes do not significantly differ from the overall average. Hopane derivatives in this coal extract are depleted in [sup 13]C compared to the bulk coal by 8-34[per thousand] suggesting that bacterial cycling of methane played a role during formation of this coal. 19 refs., 4 figs., 1 tab.

  17. 12 Blocks Open in North west China's Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    PetroChina Foreign Cooperation Administration Depa

    2006-01-01

    @@ After having opened up for 20 years, the field of oil/gas exploration and development in China is witnessing a new round of high tide to attract foreign investment.PetroChina, China's biggest oil/gas producer and supplier,decided to offer 12 blocks totaling an acreage of 110,000sq.km. in Tarim Basin to players of the industry globally.The project is the biggest oil/gas deal in China aiming at foreign cooperation for approximately 12 years, in which the 12 blocks that will be offered located mainly in southwestern, central and eastern Tarim Basin. It will enable PetroChina to combine its experience and cognition on the geological condition of Tarim Basin with the updated prospecting concept and advanced prospecting technique in the world, improve the proved degree of oil and gas resources in Tarim Basin and achieve a big breakthrough in oil and gas exploration.

  18. North-south Differentiation of the Hydrocarbon Accumulation Pattern of Carbonate Reservoirs in the Yingmaili Low Uplift, Tarim Basin,Northwest China

    Institute of Scientific and Technical Information of China (English)

    L(U) Xiuxiang; LI Jianjiao; ZHAO Fengyun; YANG Ning; ZHANG Qiucha

    2008-01-01

    By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable oil and gas accumulation series in the Tabei (northern Tarim uplift) uplift. There are different patterns of hydrocarbon accumulation on the northern and southern slopes of the Yingmaili low uplift. The north-south differentiation of oil reservoirs were caused by different lithologies of the residual carbonate strata and the key constraints on the development of the reservoir beds. The Mesozoic terrestrial organic matter in the Kuqa depression and the Palaeozoic marine organic matter in the Manjiaer sag of the Northern depression are the major hydrocarbon source rocks for the northern slope and southern slope respectively. The hydrocarbon accumulation on the northern and southern slopes is controlled by differences in maturity and thermal evolution history of these two kinds of organic matter. On the southern slope, the oil accumulation formed in the early stage was destroyed completely, and the period from the late Hercynian to the Himalayian is the most important time for hydrocarbon accumulation. However, the time of hydrocarbon accumulation on the northern slope began 5 Ma B.P. Carbonate inner buried anticlines reservoirs are present on the southern slope, while weathered crust and paleo-buried hill karst carbonate reservoirs are present on the northern slope. The northern and southern slopes had different controlling factors of hydrocarbon accumulation respectively. Fracture growth in the reservoir beds is the most important controlling factor on the southern slope; while hydrocarbon accumulation on the northern slope is controlled by weathered crust and cap rock.

  19. Water Balance Change in Xia Ying River Basin, Qinghai Province, China

    Science.gov (United States)

    Cuo, L.; Zhou, B.; Li, J.

    2010-12-01

    Yellow River, Yangtze River and Lan Cang River are major river systems supporting billions of people in South East Asia and China. Source region of Yellow River, Yangtze River and Lan Cang River (Three Rivers) is located in Qinghai Province, China. Recently, Chinese government started a conservation project in the source region of the Three Rivers called “Convert Agricultural Field to Forest and Grassland”. Xia Ying River Basin is a sub-basin located in the source region of the Three River Basin. The upper Xia Ying River Basin has experienced dramatic land cover change since 2006. Before 2006, upper Xia Ying River Basin hill slope was agricultural field. Coniferous trees and bush vegetation were planted on the slope greater than 70 degree in the upper Xia Ying River Basin in 2006. The objective of the study is to investigate the water balance term change in the Xia Ying River Basin because of the conservation project. This study will use Landsat and MODIS imagery to classify and quantify land cover classes before and after land cover conversion. Water balance terms including runoff and evaportranspiration will be simulated using a land surface model to investigate water balance term change due to land cover change. The study serves as a pilot study for the investigation of hydrological change in the entire source region of the Three River Basin during the past 50 years.

  20. Silurian to Devonian foreland basin in the south edge of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the theory of plate tectonics, combining with the isotopic dating of ophiolite, igneous and volcanics, geochemical test, rare earth element analyze and seismic interpretation, this paper studies the pre-Carboniferous tectonics and sedimentary formation of the south edge of the Tarim Basin and proves that there exists the Kunlun Ocean under tensional tectonics during the Sinian and Cambrian in the south edge of the Tarim Plate. After that, due to the collision orogenesis, there formed the peripheral foreland basin in the south edge of Tarim. The Upper Silurian and Devonian molasses sedimentary system superposed on the Sinian and Middle Silurian passive margin flysch sedimentary system and formed the bivariate structure of the foreland basin. And at the same time, based on the field geology and seismic interpretation, we have identified that the formation of the Silurian and Devonian have the character of half deposit which shows thick in the south area and thin in the north, and the pre-Carboniferous thrust compression tectonics remained in the foreland thrust belt, which further demonstrates that there existed the Silurian and Devonian peripheral foreland basin on the south edge of the Tarim Basin.

  1. Navigation Issues in the South China Sea

    OpenAIRE

    2005-01-01

    The South China Sea is one of the most important sea lanes with numerous competing sovereignty disputes. The freedom of navigation in this region is critical to all major trading States in the world. After an introduction to the navigational regimes of UNCLOS, this article describes the whole navigation situation in this region, by separately introducing the navigation issues in the territorial sea, straits, archipelagic waters and the Spratly area. Meanwhile, since the legal status of the ma...

  2. China, South Africa and the Lewis Model

    OpenAIRE

    John B. Knight

    2007-01-01

    The paper uses the Lewis model as a framework for examining the labour market progress of two labour-abundant countries, China and South Africa, towards labour shortage and generally rising labour real incomes. In the acuteness of their rural-urban divides, forms of migrant labour, rapid rural-urban migration, and high and rising real wages in the formal sector, the two economies are surprisingly similar. They differ, however, in the dynamism of their formal sector growth of output and employ...

  3. 南海北部大陆架琼东南盆地西南部新近纪沟鞭藻类%NEOGENE DINOFLAGELLATES FROM THE SOUTHWESTERN QIONG DONGNAN BASIN IN THE NORTH CONTINENTAL SHELF OF THE SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    何承全; 祝幼华; 麦文

    2005-01-01

    首次报道的低纬度晚第三纪(新近纪)丰富多样的海相沟鞭藻类,产自南海北部大陆架琼东南盆地西南部的两钻孔(主要是Ya21-1-2井,少量为Ya21-1-1井),经鉴定达40余种.文中仅对其中的31种4亚种进行了照相和对15种2亚种和1新种 (Impletosphaeridium capillare sp. nov.)在我国进行了首次描述;在新近系建立2个沟鞭藻组合:即 Hystrichosphaeropsis obscura组合(下部)和Reticulatosphaera actinocoronata-Polysphaeridium zoharyi组合(上部),并讨论了它们的组合特征及其地质时代,认为其下部的组合时代为中新世,上部的组合时代为上新世.%Rich and varied dinoflagellate cysts dealt with in this paper are obtained from the Neogene subsurface sediments of two offshore wells (mainly from well Ya21-1-2 with a depth of 1827.77-4562.79m, but a few from well Ya21-1-1 with a depth of 2413.98-3703.87m) drilled in the southwestern Qiong Dongnan(or Southeast) Basin, the North Continental Shelf of the South China Sea. More than fourty species belonging to 20 genera of dinoflagellates, Granodiscus granulatus of acritarchs, Pterospermella spp. of chlorophytes, and microforaminifer linings have been identified from well Ya21-1-2, of which 31 species of dinoflagellates are only illustrated and described in this work, including one new species, Impletosphaeridium capillare sp. nov. Two dinoflagellate assemblages have been recognized from the Neogene sediments of well Ya21-1-2 which are as follows in ascending order. 1. Hystrichosphaeropsis obscura Assemblage (at a depth of 3727.65-4562.79m) is marked by the latest occurrences of several species including Cordosphaeridium cantharellus, Bosedinia granulata, Hystrichosphaeropsis obscura and by the presence of Edwardsiella sexispinosa, Selenopemphix crenata and Impletosphaeridium capillare sp. nov. In the assemblage Hystrichokolpoma rigaudiae, H. denticulatum, Lingulodinium machaerophorum, Operculodinium centrocarpum, Polysphaeridium

  4. Mesozoic basins and associated palaeogeographic evolution in North China

    Institute of Scientific and Technical Information of China (English)

    Yong-Qing Liu; Hong-Wei Kuang; Nan Peng; Huan Xu; Peng Zhang; Neng-Sheng Wang; Wei An

    2015-01-01

    In North China, the Mesozoic terrestrial basins, sedimentary palaeogeography and tectonic settings involved ifve evolutionary stages:(1) the Early-Middle Triassic, (2) the Late Triassic to Early-Middle Jurassic, (3) the Late Jurassic to early Early Cretaceous, (4) the middle-late Early Cretaceous and (5) the Late Cretaceous. The regional punctuated tectonic events occurred during these evolutionary stages. During the Early-Middle Triassic (stage 1), the Xingmeng Orogenic Belt (XMOB, i.e., east-ern part of Central Asia Orogenic Belt, CAOB) of the northern North China was settled in the transition of tectonic environment from syn-orogenic compression to post-orogenic extension with intensive uplifting. It is a main provenance in the uniifed Ordos-North China Basin.The united continental plate of China and the Qinling-Dabie-Sulu Orogenic Belt formed due to convergence and collision between the North China Plate and the Yangtze Plate along two suture zones of the Mianlue and the Shangdan in the terminal Middle Triassic. During the Late Triassic to the Early-Middle Jurassic (stage 2), the Late Triassic maifc or alkaline rocks and intrusions occurred on the northern and southern margins of North China Craton (NCC) and XMOB, implying that intensiifed extension happened all over the North China (early phase of stage 2). Additionally, in the late phase of stage 2, the basic volcanic-iflling faulted basins were widely distributed in the northeastern North China during the Early-Middle Jurassic, including a series of small-to medium-sized basins with coal-bearing strata and some volcanic rocks in other areas of North China, which was the result of subduction of the Palaeo-Paciifc Plate during the Early-Middle Jurassic. An active continental margin with accretionary complex developed in the eastern Heilongjiang of China, Japan and the Far East of Russia at that time. However, in the end of the Early-Middle Jurassic, because of the Yan-shanian orogeny characterized by

  5. 南海西南次海盆与南沙地块的OBS探测和地壳结构%OBS survey and crustal structure of the Southwest Sub-basin and Nansha Block, South China Sea

    Institute of Scientific and Technical Information of China (English)

    丘学林; 赵明辉; 敖威; 吕川川; 郝天珧; 游庆瑜; 阮爱国; 李家彪

    2011-01-01

    跨越南海西南次海盆南部陆缘和南沙地块中部的OBS973-1测线是南海南部首次采集的海底地震仪(OBS)广角反射与折射深地震测线,本文通过震相分析和走时正演拟合,获得了沿测线的二维纵波速度结构模型.模拟结果显示表层沉积物速度2.5~4.5 km/s,厚度1000~3000m,局部基底面起伏较大.结晶基底的速度从顶部的4.5~5.5 km/s增加到地壳底部的6.8~6.9 km/s,中地壳有一个小的速度不连续面(0.1~0.2 km/s),而地壳底部的莫霍面有较大的速度反差(1.2 km/s),上地幔顶部的速度为8.0~8.1 km/s.莫霍面埋深和地壳厚度在测线的北段和南段有很大的不同,在测线北段的海盆区,莫霍面埋深约11 km,结晶地壳的厚度仅为5~6 km,表现为典型洋壳的特征,而在测线南段的陆块区,莫霍面埋深最大达24 km,地壳厚度可达20 km,表现为减薄陆壳的特征,从海盆区到陆块区莫霍面埋深和地壳厚度迅速增加.陆块区上下地壳的厚度和变化趋势相似,下地壳没有看到高速层(HVL),可能说明地壳内部是以纯剪拉张的均匀减薄为主,地壳下部的岩浆底侵不发育.对比OBS973-2和OBS973-3测线的结构模型,可以推测南沙地块的中部和东部具有相似的构造性质,西南次海盆两侧是一对非火山型的不对称共轭陆缘.%OBS973-1 is a wide angle reflection and refraction deep seismic line using Ocean Bottom Seismometers (OBS) , deployed for the first time in the southern part of South China Sea. The line crosses the southern margin of the Southwest Sub-basin and the middle part of Nansha Block. By seismic phase analysis and travel time fitting, a 2D P-wave velocity model along theline is constructed. The modeling results show that the surface sedimentary layer has a velocity of 2. 5~4. 5 km/s and a thickness of 1000~ 3000m, with locally rough basement interface. The crystalline basement has a velocity of 4. 5~5. 5 km/s on the top, increasing to

  6. First record of Podocarpoid fossil wood in South China.

    Science.gov (United States)

    Li, Long; Jin, Jian-Hua; Quan, Cheng; Oskolski, Alexei A

    2016-01-01

    A new species of fossil conifer wood, Podocarpoxylon donghuaiense sp. nov., is described from the late Eocene of Nadu Formation in Baise Basin of the Guangxi Province, South China. This fossil wood is characterized by distinct growth rings, circular to oval tracheids in cross section, 1-2-seriate opposite pits on radial tracheid walls, uniseriate (rarely biseriate) rays, smooth end walls of ray parenchyma cells, and the absence of resin ducts, suggesting its affinity to Podocarpaceae. The new species is distinctive from other Cenozoic woods ascribed to this family by the combination of distinctive growth rings, the absence of axial parenchyma, the occurrence of bordered pits on tangential tracheid walls, and the occurrence of 3-4 cuppressoid or taxodioid pits on cross-fields. This represents the first record of podocarpoid fossil wood in South China and provides fossil evidence for the early dispersal and diversification of Podocarpaceae in eastern Asia as well as for mild temperate seasonal climate in this region during the late Eocene. PMID:27571780

  7. Stratigraphy and Tectonics of the Sengkang Basin, South Sulawesi

    Directory of Open Access Journals (Sweden)

    Suyono Suyono

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v5i1.89Sulawesi was formed during the Oligocene - Miocene collision between the Eurasian Plate and micro-continental fragments detached from the Indian-Australian Plate. The Sengkang Basin situated on the South Sulawesi Province, was formed by a major north northwest - south southeast trending fault system of the Walanae Fault Zone, which was followed by the formation of Late Neogene foreland basin and syn-orogenic deposition. The fault system separated the eastern and western parts of South Sulawesi and influenced the deposition during the Late Miocene to Quaternary. The lower part of the deposition unit consists of small carbonate reefs of the Tacipi Member occupying the East Sengkang Basin, where this shallow marine facies is intercalated within or overlies marine claystones representing the base of the Walanae Formation. The middle sequence is interpreted as a delta foreset consisting of the Samaoling and Beru Members. During the deposition of these two members, the northern part of the Sengkang Basin gradually changed from a tidal and deltaic to fluvial environments. Furthermore, the upper sequence of this sedimentary unit is dominated by fluvial deposits.

  8. Quantitative Modelling of Multiphase Lithospheric Stretching and Deep Thermal History of Some Tertiary Rift Basins in Eastern China

    Institute of Scientific and Technical Information of China (English)

    林畅松; 张燕梅; 李思田; 刘景彦; 仝志刚; 丁孝忠; 李喜臣

    2002-01-01

    The stretching process of some Tertiary rift basins in eastern China is characterized by multiphase rifting. A multiple instantaneous uniform stretching model is proposed in this paper to simulate the formation of the basins as the rifting process cannot be accurately described by a simple (one episode) stretching model. The study shows that the multiphase stretching model, combined with the back-stripping technique, can be used to reconstruct the subsidence history and the stretching process of the lithosphere, and to evaluate the depth to the top of the asthenosphere and the deep thermal evolution of the basins. The calculated results obtained by applying the quantitative model to the episodic rifting process of the Tertiary Qiongdongnan and Yinggehai basins in the South China Sea are in agreement with geophysical data and geological observations. This provides a new method for quantitative evaluation of the geodynamic process of multiphase rifting occurring during the Tertiary in eastern China.

  9. South Caspian Pliocene-Anthropogenic basin (summary of existing views)

    Science.gov (United States)

    Amrakhov, Rashad; Shiraliyeva, Sevinj; Kerimova, Nailya

    2016-04-01

    On the basis of long-time integrated sedimentology, paleogeographic and structural - formation studies covering Pliocene-Anthropogenic sediments of South Caspian Basin (SCB) and design of structural - formation, paleogeographic and catagenetic models applying geophysical studies in the region, the author has interred rift nature on this basin during Pliocene-Anthropogenic stage of its evolution. It is assumed that SCB is intercontinental with absence of continental crust. Evolution of SCR started from Miocene, continental stage of development Lesser and Great Caucasus and Kopetdag. At initial stage of South Caspian rift-graben evolution the crystal uplift of Caucasus, Kopetdag and Talysh organic system took place. Extension forces within their borders caused collapse of central part of South Caspian block. We assumed that at later stage folded blocks of Lesser Caucasus and Talysh on the other hand Alborz and Kopetdagh on the other were moving apart. As a result of these riftogene processes the contemporary structure of SCB Antropogene was formed. Starting from Miocene, subsidence of central part of SCB and later movements of folded blocks of Great and Lesser Caucasus, Talysh and Elbrus occurred along Western Caspian, Sangachal - Ogurcghy deep faults and Turkmenistan thrust. During rift generation within SCB, magmatic troughs emerged in the rift zone - South Absheron, Lower Kura. Enzaly and Western Turkmenistan. Structural-formation studies with application of geophysical data acquired in the region, allow assuming that massive Godina can be considered as interrift horst with large gravity anomaly. Its generation relates to Miocene-Pliocene ages and was formed due to South Caspian riftogenesis. The following are sedimentologic evidences of South Caspian rift basin: a) Avalanche sedimentation and development of large thickness (2.5-3 km/106 years) even within border of Lower Pliocene (Productive Series); b) Morphology of Lower Pliocene molasses formation covering 600

  10. Modern sedimentation and extreme event in the South China Sea

    Science.gov (United States)

    Chen, Yu-Huang; Su, Chih-Chieh

    2016-04-01

    The South China Sea is the largest marginal sea of the northwest Pacific. It is situated at the plate boundary of the Eurasian, Philippine Sea, and Indian plates and also on the North Western Pacific corridor of typhoons. The unique tectonic and climatic environment makes it has to face the potential of seafloor destructions, like submarine landslides and slumps, and high sediment discharges which induced by typhoon from Philippine. In this study, we analysis the sediment properties of modern extreme event records in cores and attempt to evaluate the history of extreme events in the South China Sea. Twelve gravity cores were collected in the central South China Sea basin and around Taiping island by using R/V Ocean Research 1 from 2014 to 2015 and a series of analysis including multi-sensor core logger, XRF core scanner (Itrax), core surface images, X-radiographs, bulk density, grain size, Pb-210 chronology and X-ray diffractometer were conducted in this study. On core surface images, an obvious brownish oxidized layer exist in core top with higher Pb-210 activity beneath this oxidized layer, and we speculate this layer is caused by nature hazard. According to the sampling time, we conjecture the oxidized layer might formed by typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippine. The sedimentation rate of the non-event years in these cores which derived from Pb-210 chronology method is about 0.02 ~0.03 cm/yr. On contrary, the event layer caused by Haiyan with a recorded maximum 87cm deposits in the South China Sea. This study aims to characterize the typhoon induced deposits in the turbidite layer and use it to identify whether the other event layers recorded in these cores were related to typhoon activities and to reconstruct the strong tropical cyclone history in the western Pacific.

  11. Drought analysis using multi-scale standardized precipitation index in the Han River Basin, China

    Institute of Scientific and Technical Information of China (English)

    Yue-ping XU; Sheng-ji LIN; Yan HUANG; Qin-qing ZHANG; Qi-hua RAN

    2011-01-01

    Regional drought analysis provides useful information for sustainable water resources management. In this paper, a standardized precipitation index (SPI) at multiple time scales was used to investigate the spatial patterns and trends of drought in the Han River Basin, one of the largest tributaries of Yangtze River, China. It was found that, in terms of drought severity, the upper basin of the Hart River is the least, while the growing trend is the most conspicuous; a less conspicuous growing trend can be observed in the middle basin; and there is an insignificant decreasing trend in the lower basin. Meanwhile, the impact of drought on the Middle Route of the South-to-North Water Transfer Project was investigated, and it is suggested that water intake must be reduced in times of drought, particularly when successive or simultaneous droughts in the upper and middle basins of the Han River Basin occur. The results can provide substantial information for future water allocation schemes of the South-to-North Water Transfer Project.

  12. Implication of drainage basin parameters of a tropical river basin of South India

    Science.gov (United States)

    Babu, K. J.; Sreekumar, S.; Aslam, Arish

    2016-03-01

    Drainage morphometry provides quantitative description of the drainage system which is an important aspect of the characterisation of watersheds. Chalakudi River is one of the important rivers of the South India which has attracted attention of many environmental scientists recently because of the proposed Athirapally Hydel Project across the river. SRTM (Shuttle Radar Topographic Mission) data were used for preparing DEM (Digital Elevation Model), Aspect Map and Slope Map. Geographical Information System (GIS) was used for the evaluation of linear, areal and relief aspects of morphometric parameters. The study reveals that the terrain exhibits dentritic and trellis pattern of drainage. The Chalakudi River Basin has a total area of 1,448.73 km2 and is designated as seventh-order basin. The drainage density of the basin is estimated as 2.54 and the lower-order streams mostly dominate the basin. The high basin relief indicates high runoff and sediment transport. The elongation ratio of the Chalakudi Basin is estimated as 0.48 and indicates that the shape of the basin is elongated. The development of stream segments in the basin area is more or less effected by rainfall. Relief ratio indicates that the discharge capability of watershed is very high and the groundwater potential is meagre. The low value of drainage density in spite of mountainous relief indicates that the area is covered by dense vegetation and resistant rocks permeated by fractures and joints. These studies are helpful in watershed development planning and wise utilization of natural resources.

  13. Detrital zircon provenance of the Paleogene syn-rift sediments in the northern South China Sea

    Science.gov (United States)

    Shao, Lei; Cao, Licheng; Pang, Xiong; Jiang, Tao; Qiao, Peijun; Zhao, Meng

    2016-02-01

    The early rift sedimentation history of the South China Sea is still not well understood due to restricted borehole coverage of the Paleogene strata and lack of reliable stratigraphic dating. We use detrital zircon U-Pb geochronology to explore the source-to-sink characteristics of syn-rift sequences in the northern South China Sea. The results reveal significant intrabasinal provenances in addition to the well-perceived terrigenous supply from the north. The Dongsha Uplift is considered to account for the dominance of the Early Cretaceous zircons in the Eocene samples. The Lower Oligocene sediments in the Qiongdongnan Basin could have been sourced from Hainan Island and local uplifts, but their distinction cannot be confirmed by the U-Pb age spectra. Contemporary sediments in the northern Pearl River Mouth Basin were most likely transported from southeastern South China with well-rounded zircon grains showing U-Pb age similarity to those from the northeastern tributaries of the Pearl River. By contrast, intrabasinal sources from the west and east are suggested to have contributed the infill of the southern part of the Pearl River Mouth Basin based on generally euhedral zircon shapes. These sedimentary source patterns appear to change very little in the Oligocene northern South China Sea. However, the newly detected Neoproterozoic zircons in the Upper Oligocene sediments from borehole L21 tend to indicate a southern source. The episodic and diachronic nature of rifting and erosion processes in the early South China Sea is the cause of complex patterns in the Paleogene provenance history.

  14. Classification of Complex Reservoirs in Superimposed Basins of Western China

    Institute of Scientific and Technical Information of China (English)

    PANG Xiongqi; ZHOU Xinyuan; LIN Changsong; HUO Zhipeng; LUO Xiaorong; PANG Hong

    2010-01-01

    Many of the sedimentary basins in western China were formed through the superposition and compounding of at least two previously developed sedimentary basins and in general they can be termed as complex superimposed basins.The distinct differences between these basins and monotype basins are their discontinuous stratigraphic sedimentation,stratigraphic structure and stratigraphic stress-strain action over geological history.Based on the correlation of chronological age on structural sections,superimposed basins can be divided into five types in this study:(1)continuous sedimentation type superimposed basins,(2)middle and late stratigraphic superimposed basins,(3)early and late stratigraphic superimposed basins,(4)early and middle stratigraphic superimposed basins,and(5)long-term exposed superimposed basins.Multiple source-reservoir-caprock assemblages have developed in such basins.In addition,multi-stage hydrocarbon generation and expulsion,multiple sources,polycyclic hydrocarbon accumulation and multiple-type hydrocarbon reservoirs adjustment,reformation and destruction have occurred in these basins.The complex reservoirs that have been discovered widely in the superimposed basins to date have remarkably different geologic features from primary reservoirs,and the root causes of this are folding,denudation and the fracture effect caused by multiphase tectonic events in the superimposed basins as well as associated seepage,diffusion,spilling,oxidation,degradation and cracking.Based on their genesis characteristics,complex reservoirs are divided into five categories:(1)primary reservoirs,(2)trap adjustment type reservoirs,(3)component variant reservoirs,(4)phase conversion type reservoirs and(5)scale-reformed reservoirs.

  15. Modern movement and deformation in the South China Sea shown by GPS measurements and numerical simulation

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; LUAN Xiwu; YU Roger Z.

    2013-01-01

    To better understand the crustal deformation of the South China Sea Basin,we produce a mechanically consistent 2-dimensional model for observing regional velocity field in the South China Sea (SCS).We studied the dominating regional tectonic stress field by geodetic measurements and finite element analysis,the spatial variations of velocity field and strain field,and relative movements among different blocks,using a 2-dimensional model describing crustal deformation of the South China Sea Basin.Strain results show that the SCS is extending at present.The western part of SCS is opening gradually in NW-SE direction from its northern margin to the south,but the eastern part of SCS is opening gradually from its central part to the north and south.In addition,we analyzed the plate kinematics to the deformation of the SCS,using a two-dimensional finite element model.Our simulations results are well explained by available geodetic data.The movement of SCS is resulted from interactions among Indian Plate,Pacific Plate,Philippine Sea Plate,and Eurasian Plate.

  16. Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

    OpenAIRE

    Jin, X. B.; C. L. Liu; Poulton, A. J.; M. H. Dai; X.H. Guo

    2016-01-01

    Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths), and the relative cellular levels of photosynthesis and calcification. All three of these factors vary between coccolithophore species, and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition ...

  17. Source of atmospheric moisture and precipitation over China's major river basins

    Institute of Scientific and Technical Information of China (English)

    Tongtiegang ZHAO; Jianshi ZHAO; Hongchang HU; Guangheng NI

    2016-01-01

    Oceanic evaporation via the East Asian Monsoon (EAM) has been regarded as the major source of precipitation over China,but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country.To explain the contradiction,this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China's major river basins.The results show that from 1980 to 2010,the mean annual atmospheric moisture (precipitable water) over China was 13.7 mm,39% of which originates from oceanic evaporation and 61% from terrestrial evaporation.The mean annual precipitation was 737 mm,43% of which originates from oceanic evaporation and 57% from terrestrial evaporation.Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does.Particularly,for the Pearl River and southeastern rivers,oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation.Meanwhile,terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind.For the northwestern rivers,terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation.There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation,with a correlation coefficient of 0.92,among the ten major river basins in China.

  18. Source of atmospheric moisture and precipitation over China's major river basins

    Science.gov (United States)

    Zhao, Tongtiegang; Zhao, Jianshi; Hu, Hongchang; Ni, Guangheng

    2016-03-01

    Oceanic evaporation via the East Asian Monsoon (EAM) has been regarded as the major source of precipitation over China, but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country. To explain the contradiction, this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China's major river basins. The results show that from 1980 to 2010, the mean annual atmospheric moisture (precipitable water) over China was 13.7 mm, 39% of which originates from oceanic evaporation and 61% from terrestrial evaporation. The mean annual precipitation was 737 mm, 43% of which originates from oceanic evaporation and 57% from terrestrial evaporation. Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does. Particularly, for the Pearl River and southeastern rivers, oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation. Meanwhile, terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind. For the northwestern rivers, terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation. There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation, with a correlation coefficient of 0.92, among the ten major river basins in China.

  19. Main Controlling Factors on Hydrocarbon Accumulation and Distribution in Marine Sedimentary Sequences in South China

    Institute of Scientific and Technical Information of China (English)

    Cai Liguo; Zhou Yan; Bai Zhenrui

    2008-01-01

    Multiple source rock assemblages were deposited in the sedimentary provinces in South China in geologic history,and some of them were destructed by and some survived against multiple tectonic movements.Therefore,multiple sources,mixed sources,and uneven distribution of sources occurred in the marine sedimentary basins in South China during the late stage of hydrocarbon pooling.Epidiagenesis of the marine carbonate reservoirs and its modification to reservoir poroperm characteristics determined the formation and the scale of natural gas pools.The exploration practices show that the large to medium gas fields mainly occur in areas with high-quality reservoirs.Detailed study of the paleo-oil accumulations and typical oil and gas reservoirs reveals that the basins experienced multiphase superimposition and modification,leading to the distribution of the Paleozoic paleo-oil accumulations and bitumen in the peripheral areas.The phenomenon that oil and gas production concentrates in the Sichuan basin indicates that the overall sealing conditions of a basin determine the oil/gas potentials and the scale of oil and gas production.This is a critical factor controlling the accumulation and distribution of gas in the marine sequences in South China.The early oil and gas pools in the Yangtze platform left billions of bitumen in the peripheral areas due to the destruction of seals.Since the Himalayan,"late-generation and late-accumulation" gas pools represented by the gas pools in the Sichuan (四川) basin were formed in the marine sedimentary sequences in South China as a result of the change of the sealing conditions.Current gas discoveries appear to be "paleo-generation and paleo-accumulation" gas pools but actually are "late-generation and late-accumulation" gas pools.These patterns of hydrocarbon pooling clearly depict themselves in western Sichuan basin and Weiyuan (威远)gas field.It is revealed that the gas pools in the Sichuan basin were mainly formed as a result of

  20. Formation and evolution of Precambrian continental crust in South China

    Institute of Scientific and Technical Information of China (English)

    ZHENG YongFei; ZHANG ShaoBing

    2007-01-01

    The occurrence of zircons with U-Pb ages of ~3.8 Ga and Hf model ages of ~4.0 Ga in South China suggests the existence of the Hadean crustal remnants in South China. Furthermore, a detrital zircon with a U-Pb age as old as 4.1 Ga has been found in Tibet. This is the oldest zircon so far reported in China. These results imply that continental crust was more widespread than previously thought in the late Hadean, but its majority was efficiently reworked into Archean continental crust. On the basis of available zircon U-Pb age and Hf isotope data, it appears that the growth of continental crust in South China started since the early Archean, but a stable cratonic block through reworking did not occur until the Paleoproterozoic. Thus the operation of some form of plate tectonics may occur in China continents since Eoarchean. The initial destruction of the South China craton was caused by intensive magmatic activity in association with the assembly and breakup of the supercontinent Rodinia during the Neoproterozoic. However, most of the Archean and Paleoproterozoic crustal materials in South China do not occur as surface rocks, but exist as sporadic crustal remnants. Nevertheless, the occurrence of Neoproterozoic magmatism is still a signature to distinguish South China from North China.

  1. Abnormal overpressure distribution and natural gas accumulation in foreland basins, Western China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Abnormal overpressure occurs in the foreland basins of Kuqa, South Junggar and West Sichuan in China. The pressure coefficients are high. Overpressure exists in wide areas and various strata. The layers of overpressure have a very close relationship with lithology, and the area of overpressure is controlled by the piedmont depression. The mechanisms of overpressure formation in the Kuqa and South Junggar Depression include disequilibrium compaction and tectonic compression; the importance of these two factors varies in different basins and in different stages of the same basin. Different models of gas accumulation are established to explain the relationship between overpressure distribution and gas pool formation, and the influence of overpressure on the gas pools. These models include: (ⅰ) the violent tectonic movement leads to the pool formation in overpressure belt (Kela-2 gas field in Kuqa); (ⅱ) the pressure releases at shallow part and the gas pool forms in late time (Hutubi gas field in southern Junggar Basin); (ⅲ) through the pressure transfer the gas migrates and accumulates (Xinchang gas field in Western Sichuan Basin).

  2. Basin-mountain structures and hydrocarbon exploration potential of west Junggar orogen in China

    Science.gov (United States)

    Wu, Xiaozhi; He, Dengfa; Qi, Xuefeng

    2016-04-01

    Situated in northern Xinjiang, China, in NE-SW trend, West Junggar Orogen is adjacent to Altai fold belt on the north with the Ertix Fault as the boundary, North Tianshan fold belt on the south with the Ebinur Lake Strike-slip Fault as the boundary, and the Junggar Basin on the southeast with Zaire-Genghis Khan-Hala'alat fold belt as the boundary. Covering an area of about 10×104 km2 in China, there are medium and small intermontane basins, Burqin-Fuhai, Tacheng, Hefeng and Hoxtolgay, distributing inside the orogen. Tectonically West Junggar Orogen lies in the middle section of the Palaeo-Asian tectonic domain where the Siberia, Kazakhstan and Tarim Plates converge, and is the only orogen trending NE-SW in the Palaeo-Asian tectonic domain. Since the Paleozoic, the orogen experienced pre-Permian plate tectonic evolution and post-Permian intra-plate basin evolution. Complex tectonic evolution and multi-stage structural superimposition not only give rise to long term controversial over the basin basement property but also complex basin-mountain coupling relations, structures and basin superimposition modes. According to analysis of several kinds of geological and geophysical data, the orogen was dominated by compressive folding and thrust napping from the Siberia plate in the north since the Late Paleozoic. Compressive stress weakened from north to south, corresponding to subdued vertical movement and enhanced horizontal movement of crustal surface from north to south, and finally faded in the overthrust-nappe belt at the northwest margin of the Junggar Basin. The variation in compressive stress is consistent with the surface relief of the orogen, which is high in the north and low in the south. There are two kinds of basin-mountain coupling relationships, i.e. high angle thrusting and overthrusting and napping, and two kinds of basin superimposition modes, i.e. inherited and progressive, and migrating and convulsionary modes. West Junggar orogen has rich oil and gas

  3. Groundwater Systems and Resources in the Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    HOU Guangcai; LIANG Yongping; SU Xiaosi; ZHAO Zhenghong; TAO Zhengping; YIN Lihe; YANG Yuncheng; WANG Xiaoyong

    2008-01-01

    The Ordos Basin is.a large-scalesedimentary basin in northwestern China. The hydrostratigraphic units from bottom to top are pre-Cambrian metamorphic rocks, Lower Paleozoic carbonate rocks, Upper Paleozoic to Mesozoic clastic rocks and Cenozoic deposits. The total thickness is up to 6000 m. Three groundwater systems are present in the Ordos Basin, based on the geological settings, I.e. The karst groundwater system, the Cretaceous dastic groundwater system and the Quaternary groundwater system. This paper describes systematically the groundwater flow patterns of each system and overall assessment of groundwater resources.

  4. Changes and Relationships of Climatic and Hydrological Droughts in the Jialing River Basin, China.

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    Xiaofan Zeng

    Full Text Available The comprehensive assessment of climatic and hydrological droughts in terms of their temporal and spatial evolutions is very important for water resources management and social development in the basin scale. To study the spatial and temporal changes of climatic and hydrological droughts and the relationships between them, the SPEI and SDI are adopted to assess the changes and the correlations of climatic and hydrological droughts by selecting the Jialing River basin, China as the research area. The SPEI and SDI at different time scales are assessed both at the entire Jialing River basin and at the regional levels of the three sub basins. The results show that the SPEI and SDI are very suitable for assessing the changes and relationships of climatic and hydrological droughts in large basins. Based on the assessment, for the Jialing River basin, climatic and hydrological droughts have the increasing tendency during recent several decades, and the increasing trend of climatic droughts is significant or extremely significant in the western and northern basin, while hydrological drought has a less significant increasing trend. Additionally, climatic and hydrological droughts tend to increase in the next few years. The results also show that on short time scales, climatic droughts have one or two months lag impact on hydrological droughts in the north-west area of the basin, and have one month lag impact in south-east area of the basin. The assessment of climatic and hydrological droughts based on the SPEI and SDI could be very useful for water resources management and climate change adaptation at large basin scale.

  5. Changes and Relationships of Climatic and Hydrological Droughts in the Jialing River Basin, China.

    Science.gov (United States)

    Zeng, Xiaofan; Zhao, Na; Sun, Huaiwei; Ye, Lei; Zhai, Jianqing

    2015-01-01

    The comprehensive assessment of climatic and hydrological droughts in terms of their temporal and spatial evolutions is very important for water resources management and social development in the basin scale. To study the spatial and temporal changes of climatic and hydrological droughts and the relationships between them, the SPEI and SDI are adopted to assess the changes and the correlations of climatic and hydrological droughts by selecting the Jialing River basin, China as the research area. The SPEI and SDI at different time scales are assessed both at the entire Jialing River basin and at the regional levels of the three sub basins. The results show that the SPEI and SDI are very suitable for assessing the changes and relationships of climatic and hydrological droughts in large basins. Based on the assessment, for the Jialing River basin, climatic and hydrological droughts have the increasing tendency during recent several decades, and the increasing trend of climatic droughts is significant or extremely significant in the western and northern basin, while hydrological drought has a less significant increasing trend. Additionally, climatic and hydrological droughts tend to increase in the next few years. The results also show that on short time scales, climatic droughts have one or two months lag impact on hydrological droughts in the north-west area of the basin, and have one month lag impact in south-east area of the basin. The assessment of climatic and hydrological droughts based on the SPEI and SDI could be very useful for water resources management and climate change adaptation at large basin scale.

  6. Mesozoic basin evolution and tectonic mechanism in Yanshan, China

    Institute of Scientific and Technical Information of China (English)

    LIU; Shaofeng; LI; Zhong; ZHANG; Jinfang

    2004-01-01

    The Mesozoic basins in Yanshan, China underwent several important tectonic transformations, including changes from a pre-Late Triassic marginal cratonic basin to a Late Triassic-Late Jurassic flexural basin and then to a late Late Jurassic-Early Cretaceous rift basin. In response to two violent intraplate deformation at Late Triassic and Late Jurassic, coarse fluvial depositional systems in Xingshikou and Tuchengzi Formations were deposited in front of thrust belts. Controlled by transform and extension faulting, fan deltas and lacustrine systems were deposited in Early Cretaceous basins. The composition of clastic debris in Late Triassic and Late Jurassic flexural basins respectively represents unroofing processes from Proterozoic to Archean and from early deposited, overlying pyroclastic rocks to basement rocks in provenance areas. Restored protobasins were gradually migrated toward nearly NEE to EW-trending from Early Jurassic to early Late Jurassic. The Early Cretaceous basins with a NNE-trending crossed over early-formed basins. The Early-Late Jurassic and Early Cretaceous basins were respectively controlled by different tectonic mechanisms.

  7. Zooplankton Distribution in Tropical Reservoirs, South China

    Science.gov (United States)

    Lin, Qiu-Qi; Duan, Shun-Shan; Hu, Ren; Han, Bo-Ping

    2003-11-01

    The zooplankton of 18 reservoirs of South China was investigated in 2000. 61 Rotifera species, 23 Cladoceras and 14 Copepodas were identified. The most frequent Rotifera genera were Keratella, Brachionus, Trichocerca, Diurella, Ascomorpha, Polyarthra, Ploesoma, Asplanchna, Pompholyx and Conochilus. Bosmina longirostris, Bosminopsis deitersi, Diaphanosoma birgei, D. brachyurum and Moina micrura were typical of Cladocera in the reservoirs. Phyllodiaptomus tunguidus, Neodiaptomus schmackeri and Mesocyclops leuckarti were the most frequent Copepoda and M. leuckarti dominated Copepoda in most reservoirs. High zooplankton species richness with low abundance was characteristic of the throughflowing reservoir, whereas low species richness with low abundance was found in the reservoir with the longest retention time. Relative high abundance and medium species diversity were the distinction of intermediate retention time reservoirs.

  8. Cenozoic Volcanism in South China Sea and Its Vicinity and South China Sea Spreading

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The rock series, rock types and Sr-Nd isotopic dating of the Cenozoic volcanic rocks in the South China Sea are similar to those in its vicinity. On the basis of the spreading age of the South China Sea, the Cenozoic volcanic rocks are divided into three stages: the pre-spreading stage, the spreading stage and the post-spreading stage. The deep process characteristics of the asthenosphere and lithosphere may be inferred from the study on primary basaltic magma. The top layers of the asthenosphere both in the spreading stage and in the pre-spreading stage are closer to the earth surface than that in the post-spreading stage. From the pre-spreading stage to the spreading stage, the top layer of the asthenosphere decreased in depth, while the amount of interstitial partial melts increased. The evolution of the primary basaltic magma shows a progressive evolution sequence of the rifting volcanism and a faster lithospheric spreading velocity. From the spreading stage to the post-spreading stage, the top layer of the asthenosphere gradually increased in depth, but the amount of interstitial partial melts decreased. The evolution of primary basaltic magma shows a retrogressive evolution sequence of the rifting volcanism and a gradual decrease in the lithospheric spreading velocity. The depth recognized by the study on the Cenozoic volcanism demonstrates the deep environment for the formation and evolution of the South China Sea.

  9. Plate tectonic setting and genetic types of gas (oil)-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    张一伟; 陈发景; 陆克政; 漆家福

    1997-01-01

    The plate tectonic setting and genetic types of the gas (oil)-bearing basins in China are studied. Based on the history of break-up and amalgamation of Pangea, the three tectonic evolutionary megastages can be divided and the sedimentary basins in China are classified as Palaeozoic and Meso-Cenozoic basins. The Palaeozoic gas(oil)-bearing basins are mainly located in intracratonic basins, on which different types of Meso-Cenozoic basins are superimposed, and located in cratonic marginal basins and aulacogens destroyed with a slight degree, (n contrast, the Mesozoic and Cenozoic gas (oil)-bearing basins mainly formed in extensional foreland and intracontmental shortening flexural basins.

  10. A Note on the South China Sea Shallow Interocean Circulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The existing estimates of the volume transport from the Pacific Ocean to the South China Sea are summarized, showing an annual mean westward transport, with the Taiwan Strait outflow subtracted, of 3.5±2.0 Sv (1 Sv=106 m3 s-1). Results of a global ocean circulation model show an annual mean transport of 3.9 Sv from the Pacific to the Indian Ocean through the South China Sea. The boreal winter transport is larger and exhibits a South China Sea branch of the Pacific-to-Indian Ocean throughflow, which originates from the western Philippine Sea toward the Indonesian Seas through the South China Sea, as well as through the Karimata and Mindoro Straits. The southwestward current near the continental slope of the northern South China Sea is shown to be a combination of this branch and the interior circulation gyre.This winter branch can be confirmed by trajectories of satellite-tracked drifters, which clearly show a flow from the Luz6n Strait to the Karimata Strait in winter. In summer, the flow in the Karimata Strait is reversed. Numerical model results indicate that the Pacific water can enter the South China Sea and exit toward the Sulu Sea, but no observational evidence is available. The roles of the throughflow branch in the circulation, water properties and air-sea exchange of the South China Sea, and in enhancing and regulating the volume transport and reducing the heat transport of the Indonesian Throughflow, are discussed.

  11. Sustainable Agricultural Paradigm Of mountain-Oasis-Ecotone-Desert System in Inland Manasi River Basin, Xinjiang Province, Northwest China

    Science.gov (United States)

    Liu, Huiming; Chen, Weiming; Dong, Xiaobin; Zhang, Xinshi

    Manasi River basin is located in the north foot of Tianshan Mountain, south edge of Zhunger Basin, central-north Xinjiang province, with typical aridfeatures of northern China. As the pressure on water resources in Manasi river basin is mounting because of rapid economic development, its conservation becomes ever more important. Climate change is another major threat to the future of water resources of Manasi river basin. How the water resourcechanges in Manasi river basin caused by glacial ablation, will affect the typical mountain-basin terrestrial ecosystems and agricultural production in Manasi river basin? What can we cope with the ecological issues caused by glacial ablation? In this paper we show how the water-saving stratagem such asconstructing reservoir in the mountainous region, building water pipes and be used in combination with the potential of water-saving resources, and build up sustainable agricultural paradigm of mountain-oasis-ecotone-desert system to coping with the glacier retreat and ablation. The potential of water-saving instudy area were calculated which presumed that if mountainous reservoirs and water pipes were built and water-saving technology were adopted, optimized eco-productive paradigm for mountain-basin system in Manasi river basin is proposed in desertification controlling, constructing artificial grassland in the oasis is the measure to protect vegetation in the downstream desert in Manasi river basin, and stopping grazing or forbidding grazing in the downstream of serious degradation in Manasi river basin.

  12. International business negotiation in the South and North China

    OpenAIRE

    Lin, Xiaofeng; Yan, Ran; Christakopoulos, Argiris

    2008-01-01

    AbstractData: 2008 –09 – 29Level: Bachelor Thesis in Business Administration, 15 hp,Title: International business negotiation in the South and North ChinaAuthors: Xiaofeng Lin, Ran Yan, Argiris Christakopoulos,Supervisor: Leif SannerProblem: Concurred with China's economic development, the commercial activitiesamong China and different countries have become more frequent. Manyscholars have come to realize that China's different cultural background hasbeen a great extent influenced by the inte...

  13. Water Availability for Shale Gas Development in Sichuan Basin, China.

    Science.gov (United States)

    Yu, Mengjun; Weinthal, Erika; Patiño-Echeverri, Dalia; Deshusses, Marc A; Zou, Caineng; Ni, Yunyan; Vengosh, Avner

    2016-03-15

    Unconventional shale gas development holds promise for reducing the predominant consumption of coal and increasing the utilization of natural gas in China. While China possesses some of the most abundant technically recoverable shale gas resources in the world, water availability could still be a limiting factor for hydraulic fracturing operations, in addition to geological, infrastructural, and technological barriers. Here, we project the baseline water availability for the next 15 years in Sichuan Basin, one of the most promising shale gas basins in China. Our projection shows that continued water demand for the domestic sector in Sichuan Basin could result in high to extremely high water stress in certain areas. By simulating shale gas development and using information from current water use for hydraulic fracturing in Sichuan Basin (20,000-30,000 m(3) per well), we project that during the next decade water use for shale gas development could reach 20-30 million m(3)/year, when shale gas well development is projected to be most active. While this volume is negligible relative to the projected overall domestic water use of ∼36 billion m(3)/year, we posit that intensification of hydraulic fracturing and water use might compete with other water utilization in local water-stress areas in Sichuan Basin. PMID:26881457

  14. Nature, diversity of deposit types and metallogenic relations of South China

    Science.gov (United States)

    Zaw, K.; Peters, S.G.; Cromie, P.; Burrett, C.; Hou, Z.

    2007-01-01

    The South China Region is rich in mineral resources and has a wide diversity of deposit types. The region has undergone multiple tectonic and magmatic events and related metallogenic processes throughout the earth history. These tectonic and metallogenic processes were responsible for the formation of the diverse styles of base and precious metal deposits in South China making it one of the resource-rich regions in the world. During the Proterozoic, the South China Craton was characterised by rifting of continental margin before eruption of submarine volcanics and development of platform carbonate rocks, and the formation of VHMS, stratabound copper and MVT deposits. The Phanerozoic metallogeny of South China was related to opening and closing of the Tethyan Ocean involving multiple orogenies by subduction, back-arc rifting, arc-continent collision and post-collisional extension during the Indosinian (Triassic), Yanshanian (Jurassic to Cretaceous) and Himalayan (Tertiary) Orogenies. The Late Palaeozoic was a productive metallogenic period for South China resulting from break-up and rifting of Gondwana. Significant stratabound base and precious metal deposits were formed during the Devonian and Carboniferous (e.g., Fankou and Dabaoshan deposits). These Late Palaeozoic SEDEX-style deposits have been often overprinted by skarn systems associated with Yanshanian magmatism (e.g., Chengmenshan, Dongguashan and Qixiashan). A number of Late Palaeozoic to Early Mesozoic VHMS deposits also developed in the Sanjiang fold belt in the western part of South China (e.g., Laochang and Gacun). South China has significant sedimentary rock-hosted Carlin-like deposits, which occur in the Devonian- to Triassic-aged accretionary wedge or rift basins at the margin of the South China Craton. They are present in a region at the junction of Yunnan, Guizhou, and Guangxi Provinces called the 'Southern Golden Triangle', and are also present in NW Sichuan, Gansu and Shaanxi, in an area known as

  15. Petrogenesis of early Jurassic basalts in southern Jiangxi Province, South China: Implications for the thermal state of the Mesozoic mantle beneath South China

    Science.gov (United States)

    Cen, Tao; Li, Wu-xian; Wang, Xuan-ce; Pang, Chong-jin; Li, Zheng-xiang; Xing, Guang-fu; Zhao, Xi-lin; Tao, Jihua

    2016-07-01

    Early Jurassic bimodal volcanic and intrusive rocks in southern South China show distinct associations and distribution patterns in comparison with those of the Middle Jurassic and Cretaceous rocks in the area. It is widely accepted that these rocks formed in an extensional setting, although the timing of the onset and the tectonic driver for extension are debated. Here, we present systematic LA-ICP-MS zircon U-Pb ages, whole-rock geochemistry and Sr-Nd isotope data for bimodal volcanic rocks from the Changpu Formation in the Changpu-Baimianshi and Dongkeng-Linjiang basins in southern Jiangxi Province, South China. Zircon U-Pb ages indicate that the bimodal volcanic rocks erupted at ca. 190 Ma, contemporaneous with the Fankeng basalts (~ 183 Ma). A compilation of geochronological results demonstrates that basin-scale basaltic eruptions occurred during the Early Jurassic within a relatively short interval (< 5 Ma). These Early Jurassic basalts have tholeiitic compositions and OIB-like trace element distribution patterns. Geochemical analyses show that the basalts were derived from depleted asthenospheric mantle, dominated by a volatile-free peridotite source. The calculated primary melt compositions suggest that the basalts formed at 1.9-2.1 GPa, with melting temperatures of 1378 °C-1405 °C and a mantle potential temperature (TP) ranging from 1383 °C to 1407 °C. The temperature range is somewhat hotter than normal mid-ocean-basalt (MORB) mantle but similar to an intra-plate continental mantle setting, such as the Basin and Range Province in western North America. This study provides an important constraint on the Early Jurassic mantle thermal state beneath South China.

  16. Deep Processes of Basin Evolution:A Case Study of the Southern Songliao Basin and Adjacent Area,NE China in Mesozoic-Cenozoic

    Institute of Scientific and Technical Information of China (English)

    Rihui Cheng; Dongpo Wang; Linfu Xue

    2003-01-01

    In south of the Songliao Basin and adjacent area of NE China, there are several high conductive layers in crust and upper mantle. Those layers are interpreted as detachment and rheology, which represent some features of lithosphere, asthenosphere and Moho, and related to the crust-mantle structure of the continent in the study area. The differences of the crust-mantle structures in different places in the study area reflect the differences in the movement and evolution of asthenosphere, lithosphere and crust. The differences can be summarized as follows. (1) Along the south profile of MT, the buried depth of the surface of Moho is 31 ~34 km beneath the Liaohe Basin and 35~37 km beneath the west Liaoning area. Along the north profile of MT, the buried depth of Moho is 32~33 km beneath Changtu area and 36~37 km beneath Kailu area in southern Songliao Basin. The buried depth beneath the central of the Songliao Basin is 29 km.(2) The difference of thickness of lithosphere exists in the south area and the north area of Chifeng-Kaiyuan fault. The thickness of lithosphere is about 65~120 km in the south of the fault, thickening from east to west. The top surface of asthenosphere is highly uplifted in the Liaohe Basin and the highest point is about 65 km in buried depth. The thickness of lithosphere in the north of the fault is about 60~65 km, thinner about 25 km than that in the south of the fault (West Liaoning). Deep processes such as upwelling of mantle thermal flow, extension of lithosphere, underplating, and thinning and subsidence of crust, evidenced from the crust-mantle structures were the direct forces of the basin formation in the study area during the Mesozoic-Cenozoic.

  17. Crustal P-wave velocity structure and layering beneath Zhujiangkou-Qiongdongnan basins, the northern continental margin of South China Sea%南海北部珠江口-琼东南盆地地壳速度结构与几何分层

    Institute of Scientific and Technical Information of China (English)

    张中杰; 刘一峰; 张素芳; 张功成; 范蔚茗

    2009-01-01

    基于南海北部大陆边缘珠江口-琼东南盆地深水区实施的14条近垂直深反射地震探测叠加速度谱,利用Dix公式将叠加速度剖面转换为地壳层速度剖面,并利用时深转换方法构建了深度域地壳层速度模型,综合各地壳速度剖面分析了南海北部大陆边缘珠江口与琼东南盆地不同深度层次的P波速度变化趋势以及地壳几何分层特征.结果表明,琼东南盆地区可分为4~8 km沉积层(V_P为1.7~4.7 km/s)、4~10 km厚的上地壳层(V_P为5.2~6.3 km/s)、5 km左右的下地壳层(V_P为6.4~7.0 km/s)以及2~6 km厚的高速下地壳底层(V_P>7.0 km/s).V_P>7.0 km/s下地壳高速层的存在被认为是岩石圈伸展、下地壳底部底辟构造或者是残存的原始华夏下地壳基性层的地震学指示;综合研究区地球物理探测成果构建了跨越华南大陆与南海北部陆坡区剖面莫霍和岩石圈底界图像,揭示出岩石圈上地幔在华南大陆与南海北部大陆边缘的减薄特征.%Base on stack velocity spectrum dataset of 14 near-vertical deep reflection profiles in the Zhujiang River estuary-Qiongdongnan basin in the continental margin of northern South China Sea, we use Dix formula to transform the corresponding stack velocities into the crustal-layer-velocities (in TWT domain) and convert the layer velocities into the depth domain by time-depth transformation scheme. Integrating all the crustal velocity models, we analyze the spatial variation of P wave velocity in different depths and the stratified geometry of crust in the Yinggehai and Qiongdongnan basin area in the continent margin of northern South China Sea. The results demonstrate that the kinematic structure of Qiongdongnan basin can be divided into 4 ~8km thick sediment layer (V_p is 1. 7~4. 7 km/s), 4~10 km thick upper crust (V_p is 5. 2~6. 3 km/s), about 5 km thick normal lower crust (V_p is 6. 4~7. 0 km/s) and about 2~6 km thick anomalous lower crust with high

  18. Effects of Integrated Exploration in Hydrocarbon-Prospective Areas of South China

    Institute of Scientific and Technical Information of China (English)

    KongFanshu; Zhengli; LiZhiming

    2003-01-01

    The complicated topography, morphology and geology are characteristic of South China, where the frequently covered waters and igneous bodies and widely exposed carbonates are difficult to seismic survey. This paper describes the effect of combining exploration of gravitational, magnetic and electric methods in the complicated hydrocarbon areas in South China by some case histories. Many year''s exploration practices in the exploring areas of more than 20 show that the non-seismic integrated (gravity/magnetic/electric) geophysical prospecting can play an important role not only in regional assessment, basin optimization and early basin evaluation,but also in finding objective of low resistance in areas of exposed carbonate with high resistance, contouring local structure, outlining igneous body and reef, and differentiating rock facies of basement. The results of the non-seismic integrated geophysical survey have pointed out the direction for deploying next prospecting in the specific areas of South China and the valuable experiences have been accumulated to carry out hydrocarbon-hunting in the future.

  19. 珠江口盆地深水区23.8Ma构造事件地质响应及其形成机制%Geological Response and Forming Mechanisms of 23.8 Ma Tectonic Events in Deepwater Area of the Pearl River Mouth Basin in South China Sea

    Institute of Scientific and Technical Information of China (English)

    吴景富; 张功成; 王璞珺; 谢晓军; 胡圣标; 漆家福

    2012-01-01

    南海珠江口盆地深水区23.8 Ma发育一次重大构造事件并同时形成了重要的不整合界面.研究表明:(1)23.8 Ma构造事件是珠江口盆地珠二坳陷新生代构造演化的转换面,它是盆地裂陷阶段和裂后阶段的分界面,23.8 Ma之前为断裂控盆,盆地以伸展和走滑断裂系统为主;23.8 Ma之后为断裂和热作用共同控盆,到晚期以热作用为主.(2)23.8 Ma构造事件导致盆地沉积充填的突变,通过微量元素和同位素分析,23.8 Ma以前盆地物源来自东南沿海花岗岩源区,23.8 Ma以后物源来自青藏东侧及云贵高原源区.23.8 Ma界面是南海北部陆架坡折从白云主凹南侧向北侧跳跃的分界面,相应地沉积环境由浅海陆架沉积突变为陆坡深水沉积环境.(3)23.8Ma构造事件是盆地热体制的转折面,典型钻井热史定量恢复揭示地温梯度在23.8 Ma附近明显存在一个突变面,以23.8Ma为界,新生代早期到渐新世末显示地温梯度上升,指示盆地经历了拉张过程;23.8 Ma之后显示地温梯度下降,指示盆地经历热沉降过程.(4)23.8Ma构造事件是火山活动的转化面,23.8 Ma之前显示成分单一的大规模玄武质岩浆喷发作用逐渐增强,而之后玄武质岩浆喷发作用逐渐减弱.总结了23.8 Ma构造事件的动力学模型,提出了软流圈流动主导的地幔热底辟作用是南海破裂成洋的动力来源,南海扩张脊的跃迁及地幔热底辟作用改变是导致23.8 Ma构造事件的主因.%An important tectonic event and associated unconformity surface occurred in deepwater area of the Pearl River Mouth basin. South China Sea. Research results indicate: (1 )The 23. 8 Ma tectonic events is the convert face of Cenozoic tectonic evolution in Zhu Ⅱ depression of the basin, which divides the Paleogene syn-rifting stage and Neogene post rifting stage. In the former, the basin-forming mechanisms are dominated by the stretching and strike-slip faults systems, however

  20. Diversity and paleobiogeographic distribution patterns of Early and Middle Ordovician graptolites in distinct depositional environments of South China

    Institute of Scientific and Technical Information of China (English)

    Dan; GOLDMAN

    2010-01-01

    An analysis of Ordovician graptolite diversity across several distinct lithofacies belts in South China,which represent nearshore,inner-shelf,outer-shelf,slope,and basin environments,indicates that diversity increases progressively from nearshore toward the outer-shelf,acquiring its maximum in the slope facies and thereafter decreases slightly in basinal facies.When scaled against graptolite zones and more equal duration ’Time Units’,the graptolite diversity patterns of the Early and Middle Ordovician are broadly similar among the distinct environments of South China but exhibit some important differences.A synthesized graptolite diversity curve from the Early Ordovician to the Sandbian Stage of the Late Ordovician in South China displays a step-wise increase with three peaks:1) middle Floian(Early Ordovician),2) late Dapingian-early Darriwilian(Middle Ordovician),and 3) latest Darriwilian(Middle Ordovician),which closely coincide with transgressive events in South China,implying a likely correlation.The biogeographic distribution of four graptolites with different ecological preferences,Pseudisograptus,Isograptus-Parisograptus,Undulograptus austrodentatus,and Corymbograptus turgidus,displays a significant parallelism with the coast or shelf margin,suggesting that their distributions may be controlled by water depth,basin morphology,and the distance from the coast.

  1. Stress field modeling of northwestern South China Sea since 5.3 Ma and its tectonic significance

    Institute of Scientific and Technical Information of China (English)

    YANG Fengli; ZHOU Zuyi; ZHANG Na; LIU Ning; NI Bin

    2013-01-01

    Tectonically, the northwestern South China Sea (SCS) is located at the junction between three micro-plates, i.e., the Indochina, South China and Zhongsha-Xisha micro-plates, and involves three basins, i.e., the Yinggehai Basin, the Qiongdongnan Basin and Xisha Trough in the east, and the Zhongjiannan Basin in the south. Since the Pliocene (5.3 Ma), the Yinggehai Basin has experienced repeated accelerating subsidence, high thermal fluid, and widely developing mud-rich overpressure chambers, abundant mud diapers and crust-mantle mixed CO2. While a large central canyon was developed in the Qiongdongnan Basin, new rift occurred in the Xisha Trough. These characteristics demonstrate a single tectonic unit for the northwestern SCS, for which we have undertaken stress field modeling to understand its plate deformations and sedimen-tary responses. Our results demonstrate that an extension tectonic event occurred after 5.3 Ma in theYingge-hai-Qiongdongnan-Xisha trough area, which is characterized by thinner crust (3500 m). A new rift system subsequently was developed in this area;this event was mainly driven by the combined effects of different movement veloc-ity and direction of the three micro-plates, and the far-field effect of the continental collision between the Indian Plate and the Tibetan Plateau, and subduction of the Pacific Plate underneath the Eurasian Plate.

  2. South Africa offers exploratory potential in variety of basins

    Energy Technology Data Exchange (ETDEWEB)

    Broad, D.S.; Mills, S.R. (Soekor Ltd., Cape Town (South Africa))

    1993-12-06

    While the future suspension of the oil embargo against South Africa will no doubt help revitalize the region's most powerful economy, a move away from dependence on coal as the major local energy source is also likely. This could be accomplished through regional cooperation and development were it not for the ongoing conflict in Angola, the only producer of oil and gas in the Southern African Development Community. Even with world oil prices in the doldrums, massive foreign exchange savings would result from a domestic source, and in line with world trends the possibility of harnessing the gas resources of the region is increasingly seen as a possibility. For the present, those resources remain to be defined. But ENH of Mozambique is pursuing an appraisal program for Pande field with World Bank funding, while Shell and its partners are considering possibilities of Kudu field in Namiba. And while South Africa's own national oil company, Soekor, has had limited success with its search for oil during the apartheid years, offshore F-A gas field is in production, and the potential for hydrocarbons-gas in particular--requires a great deal more investigation. The colleagues have prepared a series of articles on basins off South Africa. These articles were prepared in anticipation of the completion of political reform and of the start of a licensing round, possibly during 1994. This article draws together summaries of aspects thought to be most pertinent to petroleum exploration.

  3. Magnetostratigraphy of Tertiary Rocks from Maoming Basin,Guangdong Province,China

    Institute of Scientific and Technical Information of China (English)

    王俊达; MAURICKK.SEGUIN; 等

    1994-01-01

    The Maoming Basin is one amongst a group of Cretaceous-Tertiary basins in South China.347 samples were collected from drill cores MR and MB and section MS (110°54ˊE,21°45ˊN).Most of the lithological units are of Tertiary age.The cores include the Laohuling ,Shangun,Huangniuling and Youganwo formations.The MR core(874m in length )has recorded the polarity history from Normal Zone 18 to Normal Zone 11 on the Geomagnetic Polarity Time Scale (GPTS).The strata were formed from about 42 Ma to 32Ma ,that is from Late Eocene to Early Oligocene.A mean sedimentation rate of this stratigraphic column is 8.1 cm/ka.

  4. The deep thermal characteristic of continental margin of the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Heat flow plays an important role in the study of thermal structure and thermal evolution of continental margin of the northern South China Sea. The analysis of heat flow value shows that margin heat flow in the northern South China Sea is relatively high setting, but the percentage of crustal heat flow is lower than 35% in terrestrial heat flow. The terrestrial heat flow exhibited a current of rise from the Northern Continental Margin to the Southern Central Basin. However, the proportion of crustal heat flow in terrestrial heat flow slowly dropped down in the same direction. It is suggested that the main factor causing high heat flow setting is the moving up of hot material from asthenosphere.

  5. Relationship between Crustal Structure and Tin Mineralization in South China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A close relationship between tin metallogenic and crustal structure in South China is demonstrated, which is based on a careful study on crustal structure and a detailed comparison between typical deposits in different tectonic units. Types, locations, emplacement of ore bodies and ore genesis of tin deposits are relative to crustal structure. Tin mineralization zones of South China can be divided into three tin metallogenic units including the west part corresponding to Youjiang fold belt, middle part corresponding to fold belt of Hunan-Guangdong-Jiangxi provinces and the east part corresponding to Southeast China coastal volcanic faulting depression. From the above, it is concluded that crustal compositions and structures are the main facts of Sn concentration in South China.

  6. Lithologic Hydrocarbon Deposits in Rift Lake Basins in Eastern China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Herong; HE Zongquan

    2004-01-01

    The rift lake basins in the eastern China have abundant hydrocarbon resources of lithologic deposits, which resulted from excellent source rocks and multi-type sandbodies developed during strong rifting. Vertically, the lithologic deposits are mainly distributed in the lowstand, lacustrine invasion and early highstand systems of third-order sequence corresponding to a secondary tectonic episode of strong rifting, and laterally they are closely related to various fans and turbidite sandbodies controlled by syn-sedimentary faults. A variety of lithologic traps have been developed in the rift lake basins, and they generally have favorable conditions of source-reservoir-seal assemblage and hydrocarbon accumulation dynamics, indicating that there is a great exploration potential of lithologic deposits in the rift lake basins.In order to obtain satisfactory effects of lithologic deposit exploration, it is required to combine new theories with advanced technical methods.

  7. New progresses on geothermal history of Turpan-Hami Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A comprehensive study on geothermal history of the Turpan-HamiBasin by vitrinite reflectance, fluid inclusion geothermometry, apatite fission track and 40Ar-39Ar dating displays that the main effects influencing geotemperature distribution are burial depth of the basement, heat flow, magmatic activities, as well as tectonic movement, having a rugulation to be higher in the east and north, lower in the west and south, as well as higher in the past and lower at the present. The heat of the mantle source and the Indo-China tectonic thermal event have extremely influenced matura-tion of source rocks of the upper Lower Permian and the Middle and Upper Triassic in the lndo-China epoch. While, the geothermal gradient and the weak tectonic geothermal event of the Early Yanshan Movement provided necessary heat for the maturation of source rock in coal-bearing strata of the Middle and Lower Jurassic.

  8. A numerical study of the South China Sea deep circulation and its relation to the Luzon Strait transport

    Institute of Scientific and Technical Information of China (English)

    袁东亮

    2002-01-01

    A fine-resolution MOM code is used to study the South China Sea basin-scale circulation and its relation to the mass transport through the Luzon Strait. The modal domain includes the South China Sea, part of the East China Sea, and part of the Philippine Sea so that the currents in the vicinity of the Luzon Strait are free to evolve. In addition, all channels between the South China ,Sea and the Indonesian seas are closed so that the focus is on the Luzon Strait transport. The model is driven by specified Philippine Sea currents and by surface heat and salt flux conditions. For simplicity, no windstress is applied at the surface.The simulated Luzon Strait transport and the South China Sea circulation feature a sandwich vertical structure from the surface to the bottom. The Philippine Sea water is simulated to enter the South China Sea at the surface and in the deep ocean and is carried to the southern basin by western boundary currents. At the intermediate depth, the net Luzon Strait transport is out of the South China Sea and is fed by a western boundary current flowing to the north at the base of the thermocline. Corresponding to the western boundary currents, the basin circulation of the South China Sea is cyclonic gyres at the surface and in the abyss but an anti-cyclonic gyre at the intermediate depth. The vorticity balance of the gyre circulation is between the vortex stretching and the meridional change of the planetary vorticity.Based on these facts, it is hypothesized that the Luzon Strait transports are determined by the diapycnal mixing inside the entire South China Sea. The South China Sea plays the role of a "mixing mill" that mixes the surface and deep waters to return them to the Luzon Strait at the intermediate depth. The gyre structures are consistent with the Stommel and Arons theory (1960), which suggests that the mixlng-induced circulation inside the South China Sea should be cyclonic gyres at the surface and at the bottom but an anti

  9. Records of Toba eruptions in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LlANG; Xirong

    2001-01-01

    [1]Rose,W. I., Chesner, C. A., Dispersal of ash in the great Toba eruption, 75 ka, Geology, 1987, 15: 913-917.[2]Acharyya, S. K., Basu, P. K. ,Toba ash on the Indian subcontinent and its implications for correlation of late Pleistocene alluvium, Quaternary Research, 1993, 40: 10-19.[3]Shane, P., Westgate, J., Williams, M. et al., New geochemical evidence for the youngest Toba Tuff in India, Quaternary Research, 1995, 44: 200-204.[4]Westgate, J. A., Sha ne, P. A. R., Pearce, N. J. G. et al., All Toba occurrences across Peninsular India belong to the 75000yr B. P. eruption, Quaternary Research, 1998, 50:107-112.[5]Pattan, J. N., Shane, P., Banakar, V. K., New occurrences of youngest Toba Tuff in abyssal sediments of the Central Indian Basin, Marine Geology, 1999, 155: 243-248.[6]Gasparotto, G., Spadafora, E,, Summa, V. et al., Contribution of grain size and compositional data from the Bengal Fan sediment to the understanding of Toba volcanic event, Marine Geology, 2000, 162: 561-572.[7]Dehn, J., Farrell, J. W., Schmincke, H. U., Neogene tephrochronology from Site 758 on northern Ninetyeast Ridge: Indon isian arc volcanism of the Past 5 Ma, Proceedings of the Ocean Drilling Program, Scientific Results (eds. Weissel, J. P.,Taylor, E., Alt, J. et al.), College Station, Texas, Ocean Drilling Program, 1991, 121: 273-295.[8]Lee M. Y., Wet, K. Y., Chen, Y. G., High-resolution oxygen isotope stratigraphy for the last 150000 years in the southern South China Sea, Terrestrial, Atmospheric and Oceanic Sciences TAO, 1999, 10: 239-254.[9]Biihring, C., Sarnthein, Toba ash layers in the South China Sea: Evidence of contrasting wind directions during eruption ca.74 ka, Geology, 2000, 28: 275-278.[10]Chesner, C. A., Petrogenesis of the Toba tuffs, Sumatra, Indonesia, Journal of Petrology, 1998, 39: 397-438.[11]Rampino, M. R., Self. S., Volcanic winter and accelerated glaciation follow ing the Toba super-eruption, Nature, 1992, 359:50-52.

  10. Climate modulated erosion and sediment flux control offshore crustal structure at South China Sea continental margin

    Science.gov (United States)

    Clift, P. D.; Brune, S.; Quinteros, J.

    2015-12-01

    Rifted continental lithosphere subsides as a consequence of combined crustal thinning and mantle lithosphere cooling yet basins on some continental margins experience anomalous subsidence events that postdate active extension. Deep basins on the northern margin of the South China Sea, notably the Baiyun Sag, show basement subsidence accelerating after ~21 Ma, postdating extension by several million years. Similar subsidence events are seen after 5 Ma in the Song Hong Basin and after 11 Ma in the Qiongdongnan Basin. We combine geophysical observations and numerical forward modeling to show that loading of the offshore basins by increased sediment flux caused by faster onshore erosion following Early Miocene monsoon intensification is a viable trigger for ductile flow after the cessation of active extension. Loading works in conjunction with onshore uplift to drive flow of the lower crust away from the rift axis. As well as sediment supply rates distribution patterns and drainage capture can be significant in controlling crustal flow and thinning. This illustrates that offshore basin dynamics at continental margins with weak crust can be controlled by onshore surface processes in a newly recognized form of climate-tectonic coupling.

  11. Characteristics of high arsenic groundwater in Hetao Basin, Inner Mongolia, northern China

    Institute of Scientific and Technical Information of China (English)

    YangChun Zhu; XueYong Zhao; Min Chen; YongQing Luo; Xin Zhou

    2015-01-01

    It is well known that the Hetao Basin is one of the most seriously arsenic-affected groundwater areas in China. In order to understand the characteristics of high arsenic (As) groundwater in the Basin, a brief overview of arsenic in groundwater follows. High arsenic in the Basin commonly occurs in shallow groundwater and the total arsenic concentrations range from 0.58 to 572 µg/L (average 99.73 µg/L), exceeding the maximum mandated value of 10 µg/L for drinking water in China;As(Ш) is the predominant species. The regional distribution pattern of arsenic in the groundwater increases from south/southeast to north/northwest. Hangjinhouqi and Wuyuan counties are considered as the most seriously affected areas, with high incidences of endemic arsenicosic diseases in the Hetao Basin. High groundwater arsenic correlates with the increase of well depth. Previous studies proposed that groundwater arsenic in the Basin is mainly originated from desorption of some natural solid materials in the sediments, under reducing condition. Generally, reducing condition is believed to be the primary factor for arsenic releasing from the sediment to groundwater in the region. Under inorganic or bacterial processes, Fe2O3 changes to FeS and arsenic adsorbed to Fe(OH)3 dissolves into groundwater, and As(V) is re-duced to As(Ш). Besides, reducing environments, groundwater hydraulic gradients, organic matter, pH, evapotranspiration, and soil texture are presumed to be the predominant factors that control arsenic mobilization.

  12. Origin and accumulation mechanism of shallow gas in the North Baodao slope, Qiongdongnan Basin, South China Sea%琼东南盆地宝岛北坡浅层天然气成因与成藏机制

    Institute of Scientific and Technical Information of China (English)

    黄保家; 李里; 黄合庭

    2012-01-01

    On the basis of geochemical characteristics and origins of gases in the North Baodao slope of the Qiongdongnan Basin, the gas migration and accumulation episodes and reservoir forming time are investigated and the reservoir forming model is built for the BD13 shallow gas pools. The chemical composition and carbon isotopic data of the shallow gas, are compared with the characteristics of BD19-2 high-mature gas from the south section of the same structural belt, which reveals that the shallow gas of the BD13 gas pools is a mixture of biogas/low mature gas and some mature gas. In combination with the associated condensate biomarkers and the inclusions data, it is inferred that the biogas and low mature gas in the BD13 gas pools came from the nearby immature to low mature source rocks of the Miocene to Oligocene and charged approximately 3 Ma ago; whereas the high-mature gas generated by the Yacheng Formation source rock in the Badao Sag migrated lately into the reservoirs. Geochemical and geological data show that the No.2 fault system acts as the key pathway for upward gas migration into the shallow reservoirs, and that the sand-bodies within the Miocene Meishan and Sanya Formations are the main conduits for lateral migration of the gas. This gas migration pattern implies that the Songdong-North Baodao slope has favorable gas exploration potential in the future gas exploration of the east shallow water area in the Qiongdongnan Basin.%根据琼东南盆地宝岛北坡天然气地球化学特征和来源,研究宝岛13区浅层气田运聚期次和成藏时间,建立天然气运移成藏模式.依据宝岛13区浅层天然气组成和δ13C1、δ13C2特征,并与同一构造带南部下倾方向宝岛19-2构造高成熟天然气特征比较,认为宝岛13区浅层天然气可能是以生物气/低熟气为主含有部分成熟气的混合气.结合共生的凝析油标志物特征和包裹体信息,推测生物气/低熟气源于附近未熟—低熟的中新统—渐

  13. From orogenic collapse to rifting ; structures of the South China Sea

    Science.gov (United States)

    Pubellier, M.; Chan, L. S.; Chamot Rooke, N.; Shen, W.; Ringenbach, J. C.

    2009-04-01

    The opening of the South China Sea has been a matter of debate for many years because of its internal structure, the differences between the conjugate margins and the variations of rifting and spreading directions. Although it is considered as being a back-arc basin, it is not sitting directly above a subduction zone, and the rifting process lasted for an unusually long duration. Among the specific characteristics is the early phase of rifting which took place early in place of the former Yanshanian andean-type mountain range. This stage is marked by narrow basins filled with deformed conglomerate, and initiated around 70My ago within a framework where the oblique subduction marked by igneous activity and ductile wrench faults, was replaced by orogenic collapse. The rifting stage is marked by Eocene syntectonic normal faults and occasional volcanics centres and has proceeded from NW-SE to NS extension. The NW stretching created at least two aborted basins which remained at rift stage. Extension was followed by spreading from 33 to ~20 Ma in the South China Sea. The ocean floor spreading also changed direction to NW-SE with a propagator inside the Sunda shelf from 20 to 17My ago. However the propagator opening implies that deformation is also taken by rifting around a southern wedge which in turn created strain inside the thinned crust. Another extension parallel to the margin is also observed althought the spreading was in process. The southward motion of the southern conjugate margin was later accommodated by its subduction beneath the NW Borneo wedge until completion of the Proto South China Sea subduction. Variations of rifting spreading through time and variations of structural styles are discussed in terms of boundary forces acting to the SE.

  14. Crustal structure and extension mode in the northwestern margin of the South China Sea

    Science.gov (United States)

    Gao, Jinwei; Wu, Shiguo; McIntosh, Kirk; Mi, Lijun; Liu, Zheng; Spence, George

    2016-06-01

    Combining multi-channel seismic reflection and gravity modeling, this study has investigated the crustal structure of the northwestern South China Sea margin. These data constrain a hyper-extended crustal area bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a subparallel fossil ridge in the adjacent Northwest Sub-basin. The thinnest crust is located in the Xisha Trough, where it is remnant lower crust with a thickness of less than 3 km. Gravity modeling also revealed a hyper-extended crust across the Xisha Trough. The postrift magmatism is well developed and more active in the Xisha Trough and farther southeast than on the northwestern continental margin of the South China Sea; and the magmatic intrusion/extrusion was relatively active during the rifting of Xisha Trough and the Northwest Sub-basin. A narrow continent-ocean transition zone with a width of ˜65 km bounded seaward by a volcanic buried seamount is characterized by crustal thinning, rift depression, low gravity anomaly and the termination of the break-up unconformity seismic reflection. The aborted rift near the continental margin means that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric rift, extreme hyper-extended continental crust and hotter mantle materials indicate that continental crust underwent stretching phase (pure-shear deformation), thinning phase and breakup followed by onset of seafloor spreading and the mantle-lithosphere may break up before crustal-necking in the northwestern South China Sea margin.

  15. Karst Aquifer Recharge: A Case History of over Simplification from the Uley South Basin, South Australia

    Directory of Open Access Journals (Sweden)

    Nara Somaratne

    2015-02-01

    Full Text Available The article “Karst aquifer recharge: Comments on ‘Characteristics of Point Recharge in Karst Aquifers’, by Adrian D. Werner, 2014, Water 6, doi:10.3390/w6123727” provides misrepresentation in some parts of Somaratne [1]. The description of Uley South Quaternary Limestone (QL as unconsolidated or poorly consolidated aeolianite sediments with the presence of well-mixed groundwater in Uley South [2] appears unsubstantiated. Examination of 98 lithological descriptions with corresponding drillers’ logs show only two wells containing bands of unconsolidated sediments. In Uley South basin, about 70% of salinity profiles obtained by electrical conductivity (EC logging from monitoring wells show stratification. The central and north central areas of the basin receive leakage from the Tertiary Sand (TS aquifer thereby influencing QL groundwater characteristics, such as chemistry, age and isotope composition. The presence of conduit pathways is evident in salinity profiles taken away from TS water affected areas. Pumping tests derived aquifer parameters show strong heterogeneity, a typical characteristic of karst aquifers. Uley South QL aquifer recharge is derived from three sources; diffuse recharge, point recharge from sinkholes and continuous leakage of TS water. This limits application of recharge estimation methods, such as the conventional chloride mass balance (CMB as the basic premise of the CMB is violated. The conventional CMB is not suitable for accounting chloride mass balance in groundwater systems displaying extreme range of chloride concentrations and complex mixing [3]. Over simplification of karst aquifer systems to suit application of the conventional CMB or 1-D unsaturated modelling as described in Werner [2], is not suitable use of these recharge estimation methods.

  16. Post-breakup Basin Evolution along the South-Atlantic Margins

    Science.gov (United States)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2014-05-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  17. Water Pricing Policy in Tarim Basin of China

    Institute of Scientific and Technical Information of China (English)

    施祖麟; 许丽芬

    2001-01-01

    China ranks the thirteenth among countries with serious water shortage problems in the world. The average amount of water owned per person is only 2400 m3/year, which is about 1/4 of the world average. But unfortunately, the efficiency of water use, especially in agriculture in some arid areas, is very low, only 20% -30% in some areas. The main reason is that water prices are too iow to protect the water resources. In this paper, the Tarim Basin of southern Xinjiang is selected to study the water supply costs and farmer's tolerance of water expenses based on a great amount of data collected in the four prefectures in the Tarim Basin. Then, three steps are suggested for water pricing reform in the Tarim Basin. Finally, several possible water pricing patterns are presented, such as water coupons, seasonal floating prices, and water price counting in kind but paying in currency. The conclusion is that the present water price system should be reformed and the water price can be increased to some extent for agricultural use even in Xinjiang, a developing area in China.

  18. Applied Sequence Stratigraphy in Nonmarine Basin of China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a preliminary summary of the applied sequence stratigraphy in nonmarine basins in China. The geological and geophysical data show that the nonmarine sequences mainly resulted from both allocyclic and autocyclic processes where the most important factors were isolated tectonics and climate. However, the environmental factor should have been crucial. The depositionai base level served as the sea level in the marine environment, while the water table, lake level and fluvial equilibrium were profiled in a terrigenous environment. This accommodation varied periodically with the base level, resulting in the formation of a series of depositional sequences in terms of genesis and space. Basically, the base level of the inner continent was not affected by the changes in the relative sea level. But there would have been some relations between the changes in the relative sea level and that in the continental base level during eustacy flooding. However, a small time lag existed between the changes in the marine basin and the inner continent basin, The lake basin is smaller than the marine basin,but its velocity of sediment supply is greater than that of the marine basin. Therefore, the number of nonmarine sequences is greater than that of marine ones in the same period. It is important to recognize the system tracts for the study of high-precision or high-resolution sequence stratigraphy, especially to analyze the Iow-stand systems tract with its depositional system. The sequence boundary is genetically characterized by subaerial exposure, stratigraphic truncation and subaqueous erosion. The deposition analysis of Zhanhua depression reveals 5 sequence architectures: alluvial-fluvial/lacustrine architecture,transitional architecture formed between haline (mesohaline) lake and fresh lake, marine duration-deep lacustrine architecture, half deep lacustrine-ramp architecture and fluvial-alluvial plain architecture.During the major development of the nonmarine

  19. Bathymetric Inversion of South China Sea from Satellite Altimetry Data

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper focuses on the study of ocean bathymetric inversion from satellite altimeter data by using FFT technique.In this study,the free-air gravity anomalies over the South China Sea are determined by the satellite altimeter data of GEOSAT,ERS-1,ERS-2 and T/P.And the 2.5′×2.5′ bathymetry model in South China Sea is calculated from the gravity anomalies with the inversion model given.After the analysis of the inversion and the comparison between the results,some conclusions can be drawn.

  20. Proposed new Lower Triassic stages in South China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As the global Lower Triassic stages are not properly defined, a Chinese scheme of the Lower Triassic subdivision was recently proposed to meet the insistent need of the general investigation in China. The Lower Triassic sequences of South China are briefly summarized and the twofold Lower Triassic subdivision is discussed. The type sections of the two Chinese Lower Triassic stages, Yinkengian and Chaohuan, and their definitions are stated.

  1. Nutrient Management for Eucalypt Plantations in South China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Eucalypts are very popular for revegetation in many parts of south China because of their capacity to tolerate degraded sites and unfertile soils,and their fast growth potential to coppice. This paper reviews a decade of field trials in china, undertaken as part of several bilateral researchprograms in plantation forestry, concerning the use of fertilizers, harvest residue management and inoculation with ectomycorrhizal fungi. One of the key questions addressed is whether the productivity of plantation ...

  2. Trends of sea level rise in the South China Sea during the 1990s: An altimetry result

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Using 7 years of TOPEX/POSEIDON satellite altimetry data, we have identified a general trend of sea level rising in the South China Sea between January 1993 and December 1999. The estimated bulk rising rate of the entire basin is ~1 cm/a. The rise of sea level appears to be spatially non-homogeneous, which shows a highest rate of 2.7 cm/a in the deep basin west of Luzon and generally Iow (even negafive) rates over the shallow continental shelves. It is believed that the observed rapid rising of sea level is a regional phenomenon and is mainly caused by warming of the upper layer of the South China Sea, which showed a bulk warming rate of 0.15℃/a in the same period. It is also suggested that the observed rising trend is mainly a decadal signal, which is possibly associated with decadal variation of the Pacific warm pool region.

  3. South Africa Keen to Tap China's Tourism Market

    Institute of Scientific and Technical Information of China (English)

    Li Zhen

    2010-01-01

    @@ On August 23,South African president Jacob Zuma arrived in Beijing,starting a four-day to China.The visit is set to strengthen business ties and broaden political and cultural relationship between the two countries.President Zuma was accompanied by a group of senior ministers and a delegation of more than 200 leading South African businessmen and entrepreneurs.A business seminar between the two countries was also held.

  4. 中国太湖流域(江苏南部)人群复合污染经口途径暴露风险评估%Oral exposure risk assessment of combined pollution in Taihu Lake Basin of South Jiangsu Province, China

    Institute of Scientific and Technical Information of China (English)

    杨彦; 王宗庆; 李定龙; 于云江

    2013-01-01

    The pollution of Cu, Pb, Cd and other heavy metals and organic contaminants (DDTs) in oral media (groundwater, soil, crops, 389) from Wuxi, Changzhou and Zhenjiang in the Taihu Lake Basin (south China) were analyzed by laboratory testing. The exposure risk assessment model recommended by U. S. EPA was used. The residents' oral route of exposure risk in Taihu Lake Basin was assessed with the measured exposure parameters and the dietary habits in China were considered. The results showed that the pollution of heavy metals and organic pollutants were serious in Taihu Lake Basin. The population risk of exposure by oral estimated by the traditional way in Taihu Lake Basin showed that the total exposure risk was 9. 07 × 10 to male and 1.00 × 10-2 to female. Considering the oral exposure risk in basin by the factors of the integrated treatment, the total exposure risk was 3.94 × 10-3 to male and 4. 35 × 10 -2 to female. The exposure risks food source by oral media from traditional methods and from post - integrated treatment were both higher than the acceptable level of risk. Carcinogenic risk was significantly higher than non-cancer risk, and the carcinogenic risk of Cd played an important role to the total risk of exposure. The carcinogenic risk of Pb was lower than that of Cd.%对太湖流域(江苏南部)无锡、常州、镇江3市经口介质(地下水、土壤、农作物共389个样品)中Cu、Pb、Cd等8种重金属和有机污染物DDTs的污染状况进行实验室分析,运用US EPA推荐的暴露风险评估模型,对研究区人群进行了暴露参数实测,考虑中国居民膳食习惯,对太湖流域居民经口途径的暴露风险进行评估.研究结果表明:太湖流域重金属、有机污染物污染较严重;传统方式估算的太湖流域人群经口暴露风险,男性总暴露风险为9.07 × 10-3,女性为1.00×10-2;考虑综合处理因素的流域人群经口暴露风险,男性为3.94×10-3,女性为4.35×10-3.食物源经口介质

  5. Basin mass dynamic changes in China from GRACE based on a multibasin inversion method

    Science.gov (United States)

    Yi, Shuang; Wang, Qiuyu; Sun, Wenke

    2016-05-01

    Complex landforms, miscellaneous climates, and enormous populations have influenced various geophysical phenomena in China, which range from water depletion in the underground to retreating glaciers on high mountains and have attracted abundant scientific interest. This paper, which utilizes gravity observations during 2003-2014 from the Gravity Recovery and Climate Experiment (GRACE), intends to comprehensively estimate the mass status in 16 drainage basins in the region. We propose a multibasin inversion method that features resistance to stripe noise and an ability to alleviate signal attenuation from the truncation and smoothing of GRACE data. The results show both positive and negative trends. Tremendous mass accumulation has occurred from the Tibetan Plateau (12.1 ± 0.6 Gt/yr) to the Yangtze River (7.7 ± 1.3 Gt/yr) and southeastern coastal areas, which is suggested to involve an increase in the groundwater storage, lake and reservoir water volume, and the flow of materials from tectonic processes. Additionally, mass loss has occurred in the Huang-Huai-Hai-Liao River Basin (-10.2 ± 0.9 Gt/yr), the Brahmaputra-Nujiang-Lancang River Basin (-15.0 ± 1.1 Gt/yr), and Tienshan Mountain (-4.1 ± 0.3 Gt/yr), a result of groundwater pumping and glacier melting. Areas with groundwater depletion are consistent with the distribution of cities with land subsidence in North China. We find that intensified precipitation can alter the local water supply and that GRACE can adequately capture these dynamics, which could be instructive for China's South-to-North Water Diversion hydrologic project.

  6. PetroChina and Kuwait to Construct Joint Venture Refinery in South China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ PetroChina, China's largest oil producer and Asia's most profitable company, and Kuwait may build a planned joint venture oil refinery in South China's Pearl River Delta area, according to Guangdong Province's Executive Vice Governor Zhong Yangsheng, who told reporters at the Boao Forum for Asia in Hainan Province in late April.However, he declined to provide further details. The Pearl River Delta region accounts for about a third of the nation's exports.

  7. Bumper harvest of super rice in south and north China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Recently. a great progress was made in breeding and cultivation of super rice in China. The South Demonstration Acceptance Meeting of China Super Rice was held in Oct 17. 2000 in Xinchang County, Zhejiang Province. Yield monitoring group organized by the Department of Science,Technology and Education, Ministry of Agriculture, China, was consisting of famous rice research scientists, agricultural technology extension experts, and government officials. In the demonstration meeting, the group investigated the rice growth of the demonstration field of the improved integrated cultivation technology of super hybrid rice, Xieyou 9308. Four representative demonstration fields from 6.87 ha of the demonstration were harvested after the current investigation of the group.

  8. New production in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    CAI; Pinghe

    2002-01-01

    estuary, Acta Oceanologica Sinica (in Chinese), 1993, 15(4): 50-55.[12]Okubo, T., Furuyama, K., Sakanoue, M., Distribution of 228Ra in surface sea water of the east Indian Ocean, Geochimica Journal, 1979, 13: 201-206.[13]Moore, W. S., Oceanic concentrations of 228Ra, Earth and Planetary Science Letters, 1969, 17: 437-446.[14]Sakanoue, M., Okubo, T., Furuyama, K., 228Ra in sea water, in Isotope Marine Chemistry (eds. Goldberg, E. D., Horibe, Y., Saruhashi, K.), Tokyo: Uchida Rokakuho Publishing Co. Ltd, 1980.[15]Dunne, J. P., Murray, J. M., Rodier, M. et al., Export flux in the western and central equatorial Pacific: Zonal and temporal variability, Deep-Sea ResearchⅠ, 2000, 47: 901-936.[16]Diego-McGlone, M. L. S., Jacinto, G. S., Dupra, V. C. et al., A comparison of nutrient characteristic and primary produc-tivity in the Sulu Sea and South China Sea, Acta Oceanographica Taiwanica, 1999, 37(3): 219-229.[17]Emerson, S., Quay, P., Karl, D. et al., Experimental determination of organic carbon flux from open-ocean waters, Nature, 1997, 389: 951-954.

  9. Origin of back-arc basins and effects of western Pacific subduction systems on eastern China geology

    Science.gov (United States)

    Niu, Y.

    2013-12-01

    Assuming that subduction initiation is a consequence of lateral compositional buoyancy contrast within the lithosphere [1], and recognizing that subduction initiation within normal oceanic lithosphere is unlikely [1], we can assert that passive continental margins that are locations of the largest compositional buoyancy contrast within the lithosphere are the loci of future subduction zones [1]. We hypothesize that western Pacific back-arc basins were developed as and evolved from rifting at passive continental margins in response to initiation and continuation of subduction zones. This hypothesis can be tested by demonstrating that intra-oceanic island arcs must have basement of continental origin. The geology of the Islands of Japan supports this. The highly depleted forearc peridotites (sub-continental lithosphere material) from Tonga and Mariana offer independent lines of evidence for the hypothesis [1]. The origin and evolution of the Okinawa Trough (back-arc basin) and Ryukyu Arc/Trench systems represents the modern example of subduction initiation and back-arc basin formation along a (Chinese) continental margin. The observation why back-arc basins exit behind some subduction zones (e.g., western Pacific) but not others (e.g., in South America) depends on how the overlying plate responds to subduction, slab-rollback and trench retreat. In the western Pacific, trench retreat towards east results in the development of extension in the upper Eurasian plate and formation of back-arc basins. In the case of South America, where no back-arc basins form because trench retreat related extension is focused at the 'weakest' South Mid-Atlantic Ridge. It is thus conceptually correct that the South Atlantic is equivalent to a huge 'back-arc basin' although its origin may be different. Given the negative Clayperon slope of the Perovskite-ringwoodite phase transition at the 660 km mantle seismic discontinuity (660-D), slab penetration across the 660-D is difficult and

  10. Comparative analysis of post-breakup basin evolution along the South-American and South-African margins, southern Atlantic

    Science.gov (United States)

    Strozyk, F.; Back, S.; Kukla, P. A.

    2012-04-01

    Recently, considerable attempts have been made to compare the sedimentary basin evolution and the associated tectonic framework on both sides of the South-Atlantic. However, yet there are still unresolved questions concerning the tectono-sedimentary styles of margin basin evolution that markedly differ from north to south. Amongst the most striking observations is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic margin segment on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. Adding to the heterogeneity of the system, the northernmost segment of the South Atlantic rift and salt basins is also characterized by a pronounced asymmetry, with the Brazilian margin now comprising narrower and deeper rift basins with less salt than the Congo-Gabon conjugate margin. This project deals with a large-scale comparison of this very different post-breakup tectono-stratigraphic development of the southern and northern South American and African continental margins that both record thick post-rift sedimentary successions. To gain detail of the basin margin evolution, we focus on a regional comparison between the post-breakup records archived in the large offshore southern Brazil basins (Pelotas, Santos, Campos) and the post-breakup continental margin successions of offshore Namibia (e.g. Orange Basin) and southern Angola (e.g. Kwanza Basin). A tectonic-stratigraphic comparison of representative geological transects provides a comprehensive basin-to-basin documentation of key factors influencing margin development which include the subsidence development through time, the sediment (in-)flux and storage patterns and the respective type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems). Data from the salt-prone areas offshore South America and southern

  11. Paleomagnetic Results From Triassic Rock Formations of Junggar Basin, NW China

    Science.gov (United States)

    Zhao, X.; Li, J.; Guo, R.; Zhang, W.; Yuan, W.

    2015-12-01

    Our knowledge of the kinematics and duration of collisional events between the Chinese blocks and Siberia is still inadequate. Likewise, the accretionary history of the Central Asian fold belt itself is contentious. The primary goal for this study was to address key questions about the geographic positions of the Junggar Basin in Paleozoic and Mesozoic times and its tectonic relationship with other major Asian blocks by generating high-quality paleomagnetically inferred paleolatitudes and basin histories. Another objective is to see what it can tell us about intraplate motions within central Asia and to recognize vertical-axis tectonic rotations in the region. We collected 348 samples from 42 sites in Paleozoic and Mesozoic stratigraphic sections of east Junggar Basin. Useful results were obtained by progressive demagnetization for sandstone samples of Xiaoquan Formation dated paleontologically as mid to late Triassic. The ChRM direction for the Xiaoquan Formation is directed easterly with intermediate to steep downward inclination in geographic coordinates. After tectonic correction, the mean direction of the ChRM becomes northeasterly with intermediate to shallow inclination, which corresponds to a mean paleolatitude of 20.7° within a 95% confidence band of ± 12 degrees. It is obvious from the data that Junggar and other major parts of eastern Asia did not occupy the same relative positions in terms of paleolatitudes in Late Triassic. Paleomagnetic declinations indicate clockwise vertical-axis rotations of R = 98.3° +/- 16° for the Late Triassic rock unit relative to North China Block (NCB), and 12.4° +/- 16.2° relative to South China Block (SCB). The paleomagnetically inferred latitudinal displacements between Junggar and SCB are general statistically insignificant, as well as the rotational data. These data suggest that Junggar Basin may have been very close to SCB during the Triassic time. A plausible cause of the rotation is the westward rotational

  12. Clay Mineral Distribution Patterns of Tertiary Continental Oil-bearing Basins in China

    Institute of Scientific and Technical Information of China (English)

    Zhao Xingyuan

    1996-01-01

    @@ Induction This paper studies the clay mineral distribution patterns of Tertiary continental oil-bearing basins in China. More than 9 000 shale samples from Paleogene (E) to Neogene (N) Series distributed in Bohai Gulf, Subei, Jianghan,Nanxiang, Zhoukou, Sanshui, Beibu Bay, East China Sea,Hetao, Juiquan, Qaidam and Tarim basins, and so on.

  13. Boundaries of Consent: Stakeholder Representation in River Basin Management in Mexico and South Africa

    NARCIS (Netherlands)

    Wester, P.; Merrey, D.J.; Lange, M.

    2003-01-01

    Increasing the capacity of water users to influence decision-making is crucial in river basin management reforms. This article assesses emerging forums for river basin management in Mexico and South Africa and concludes that the pace of democratization of water management in both is slow. Mexico is

  14. Suggestion of a dynamic model of North China basin-range system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It is found from preliminary studies that previous basin-range models have difficulties in explaining the formation of the Mesozoic North-China basin-range system. This work suggests a new model-"tectonic thermal erosion" model, which considers the North China basin of Late Mesozoic and its peripheral ranges as a unified system, identifies relationship between upwelling and lateral spreading of the asthenolith with horizontal movement and deformation of the upper crust in the system, clarifies the effects of underplating erosion on the crustal evolution, and tries to establish an earth-dynamic model of the North China Mesozoic basin-range supported by numerical simulation.

  15. Antecedents of Medical Workplace Violence in South China

    Science.gov (United States)

    Cai, Wenzhi; Deng, Ling; Liu, Meng; Yu, Min

    2011-01-01

    It has been noted that workplace violence most frequently occurs in hospitals. The purpose of this study was to explore antecedents of workplace violence in south China. The authors conducted face-to-face, in-depth, semistructured interviews with 30 hospital staff who had experienced at least one incident of workplace violence from patients during…

  16. Field experiment on transgenic cassava proves successful in South China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A pioneer study on field tests of transgenic cassava (Manihot esculenta Crantz) by a Sino-Swiss research consortium has proved successful. The experiment was carried out in 2006 at an experimental station in Haikou, capital of south China's Hainan Province.

  17. Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

    Science.gov (United States)

    Miller, J. R.; Mackin, G.; Lechler, P.; Lord, M.; Lorentz, S.

    2013-02-01

    The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela Basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of eastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits of the upper and upper-mid subcatchments are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within these wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from upper to lower catchment areas was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during

  18. Numerical assessment of factors affecting nonlinear internal waves in the South China Sea

    Science.gov (United States)

    Li, Qiang

    2014-02-01

    Nonlinear internal waves in the South China Sea exhibit diverse characteristics, which are associated with the complex conditions in Luzon Strait, such as the double ridge topography, the Earth’s rotation, variations in stratification and the background current induced by the Kuroshio. These effects are individually assessed using the MITgcm. The performance of the model is first validated through comparison with field observations. Because of in-phased ray interaction, the western ridge in Luzon Strait intensifies the semidiurnal internal tides generated from the eastern ridge, thus reinforcing the formation of nonlinear internal waves. However, the ray interaction for K1 forcing becomes anti-phased so that the K1 internal tide generation is reduced by the western ridge. Not only does the rotational dispersion suppress internal tide generation, it also inhibits nonlinear steepening and consequent internal solitary wave formation. As a joint effect, the double ridges and the rotational dispersion result in a paradoxical phenomenon: diurnal barotropic tidal forcing is dominant in Luzon Strait, but semidiurnal internal tides prevail in the deep basin of the South China Sea. The seasonal variation of the Kuroshio is consistent with the seasonal appearance of nonlinear internal waves in the South China Sea. The model results show that the westward inflow due to the Kuroshio intrusion reduces the amplitude of internal tides in the South China Sea, causing the weakening or absence of internal solitary waves. Winter stratification cannot account for the significant reduction of nonlinear internal waves, because the amplitude growth of internal tides due to increased thermocline tilting counteracts the reduced nonlinearity caused by thermocline deepening.

  19. Tectonics and Petroleum Potential of the East China Sea Shelf Rift Basin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are two Cenozoic sedimentary basins in the East China Sea. They are the East China Sea shelf basin and the Okinawa Trough basin. The former can be divided into a western and an eastern rift region. The development of the shelf basin underwent continental-margin fault depression, post-rift and then tectonic inversion stages. Available exploration results show that the distribution of source rocks is controlled by the basin architecture and its tectonic evolution. In the Xihu depression, mudstones and coals are the main source rocks. The eastern rift region has good geological conditions for the formation of large oil and gas fields.

  20. Deepwater oil and gas field development in South China Sea

    Institute of Scientific and Technical Information of China (English)

    Zhang Dagang; Wybro Pieter; Kang Yongtian

    2013-01-01

    This paper focuses on potential development models of future oil and gas exploration in South China Sea.A detailed study of current development models worldwide is performed through some examples of industry installed/ongoing projects and major technical issues encountered during these practice.Key technologies are discussed for the success of field development.Some of the technologies and field development experience can be used for South China Sea project.Several models are studied in field development for different scenarios,including marginal field,large oil field and gas field.With the massive investment activities,continued improved technologies,and rapidly growing pool of professionals,the offshore industry in China will soon encounter a golden period.

  1. Climate warming, euxinia and carbon isotope perturbations during the Carnian (Triassic) Crisis in South China

    Science.gov (United States)

    Sun, Y. D.; Wignall, P. B.; Joachimski, M. M.; Bond, D. P. G.; Grasby, S. E.; Lai, X. L.; Wang, L. N.; Zhang, Z. T.; Sun, S.

    2016-06-01

    The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont apatite indicate a double-pulse warming event. The CHE coincided with an initial warming of 4 °C. This was followed by a transient cooling period and then a prolonged ∼7 °C warming in the later Carnian (Tuvalian 2). Carbon isotope perturbations associated with the CHE of western Tethys occurred contemporaneously in South China, and mark the start of a prolonged period of carbon cycle instability that persisted until the late Carnian. The dry-wet transition during the CHE coincides with the negative carbon isotope excursion and the temperature rise, pointing to an intensification of hydrologic cycle activities due to climatic warming. While carbonate platform shutdown in western Tethys is associated with an influx of siliciclastic sediment, the eastern Tethyan carbonate platforms are overlain by deep-water anoxic facies. The transition from oxygenated to euxinic facies was via a condensed, manganiferous carbonate (MnO content up to 15.1 wt%), that records an intense Mn shuttle operating in the basin. Significant siliciclastic influx in South China only occurred after the CHE climatic changes and was probably due to foreland basin development at the onset of the Indosinian Orogeny. The mid-Carnian biotic crisis thus coincided with several phenomena associated with major extinction events: a carbonate production crisis, climate warming, δ13 C oscillations, marine anoxia, biotic turnover and flood basalt eruptions (of the Wrangellia Large Igneous Province).

  2. Badlands in humid regions - redbed desertification in Nanxiong Basin, China

    Science.gov (United States)

    Yan, Luobin; Hua, Peng; Simonson, Scott

    2016-04-01

    The redbed badlands in Nanxiong City, China, well represent badlands in humid regions. The erosion rate in humid regions is much higher than that in arid regions and can reach 1 cm per month during the summer. The purpose of this study is to introduce the research of badlands in China, which have not been extensively studied so far, and to compare the badlands between arid and humid regions. Furthermore, the aim is to study the impact of mineralogical and chemical composition on the disintegration of soft rock in Nanxiong Basin badlands. For the purpose of this study field observations, sampling, and digging profiles were done. The mineralogical and chemical compositions of the Nanxiong Basin badland lithologies were determined by XRD, XRF and thin sections. Weathering resistance, process of weathering, and disintegration features were studied by weathering experiments under natural conditions. Weathering profiles can be easily divided into four layers: regolith, a strongly weathered layer, a poorly weathered layer, and an unweathered sediment. The depth of the weathering profile is influenced by the weathering resistance of the soft rock. Weathering resistance affects the erosion rate and evolution of landforms in badlands by influencing the rate from unweathered rock to regolith. Analyzed sediments have high content of illite and illite-smectite interstratifications. This composition of clay minerals together with poor sediment consolidation jointly leads to weathering prone sediment. The weathering and disintegration of soft rock in Nanxiong Basin badlands has a close relationship with rainfall. Sheet erosion, a kind of solid-liquid phase flow, formed in the regolith of the badland during rainfall events and can be the most instrumental to erosion. The mineral composition and liquidity plasticity index were also analyzed, and the results show that the regolith are low liquid limit silts with liquid limit of 21%-25%, plastic limit of 13%-18% and plasticity index

  3. Yardangs in the Qaidam Basin, northwestern China: Distribution and morphology

    Science.gov (United States)

    Li, Jiyan; Dong, Zhibao; Qian, Guangqiang; Zhang, Zhengcai; Luo, Wanyin; Lu, Junfeng; Wang, Meng

    2016-03-01

    The northwestern Qaidam Basin exposes one of the largest and highest elevation yardang fields on Earth. The aim of the present study was to describe the distribution and morphology of these yardangs, and analyze the factors responsible for the distribution pattern of these aeolian landforms. The yardang fields are bounded by piedmont alluvial-diluvial fans from the mountain ranges surrounding the basin, except in the south, where they are bounded by dune fields, dry salt flats, lakes, and rivers. This distribution pattern can be attributed to regional tectogenesis and its corresponding environmental impacts. The morphology of the yardangs varies considerably in response to the diverse factors that control their formation and evolution. Long-ridge yardangs are mainly located in the northernmost part of the yardang field, and the long ridges are gradually dissected into smaller ridges in the downwind direction. Further downwind, the convergence of northerly and northwesterly winds and the effects of temporary runoff cause the ridges to gradually transition into mesa yardangs. Saw-toothed crests, and conical and pyramidal yardangs, occur in groups on folded brachyanticlinal structures. Typical whaleback yardangs are found in the southeast, at the northern margin of Dabuxun Lake. Morphological parameters vary among the yardang types. The orientation of the yardangs in the northernmost area is nearly N-S, with a transition towards NW-SE in the southernmost area in response to a change in the dominant wind direction that results from the orientations and positions of the mountain ranges that surround the basin.

  4. Numerical Analysis and Simulation Experiment of Lithospheric Thermal Structures in the South China Sea and the Western Pacific

    Institute of Scientific and Technical Information of China (English)

    Lin Ge; Peng Meili; Zhao Chongbin; Zhang Lu; Zhang Desheng; Liu Shilin

    2009-01-01

    The asthenosphere upwelled on a large scale in the western Pacific and South China Sea during the Cenozoic,which formed strong upward throughflow and caused the thermal structure to be changed obviously.The mathematical analysis has demonstrated that the upward throughflow velocity may have varied from 3×1011 to 6×1012 m/s.From the relationship between the lithospheric thickness and the conductive heat flux,the Hthospherie heat flux in the western Pacific should be above 30 mW/m2,which is consistent with the observed data.The huge low-speed zone within the upper mantle of the marginal sea in the western Pacific reflects that the upper mantle melts partially,flows regionally in the regional stress field,forms the upward heat flux at its bottom,and causes the change of the lithospheric thermal structure in the region.The numerical simulation result of the expansion and evolution in the South China Sea has demonstrated that in the early expansion,the upward throughflow velocity was relatively fast,and the effect that it had on the thickness of the lithosphere was relatively great,resulting in the mid-ocean basin expanding rapidly.After the formation of the ocean basin in the South China Sea,the upward throughflow velocity decreased,but the conductive heat flux was relatively high,which is close to the actual situation.Therefore,from the heat transfer point of view,this article discusses how the upward heat flux affects the lithospheric thermal structure in the western Pacific and South China Sea.The conclusions show that the upward heat throughflow at the bottom of the llthospheric mantle resulted in the tectonic deformation at the shallow crust.The intensive uplifts and rifts at the crust led to the continent cracks and the expansion in the South China Sea.

  5. Deepwater Ventilation and Stratification in the Neogene South China Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The results indicate that 3 lithostratigraphic units, respectively corresponding to 21-17 Ma, 15-10 Ma, and 10-5 Ma with positive red parameter (a*) marking the red brown sediment color represent 3 periods of deep water ventilation. The first 2 periods show a closer link to contemporary production of the Antarctic Bottom Water (AABW) and Northern Component Water(NCW), indicating a free connection of deep waters between the SCS and the open ocean before 10 Ma.After 10 Ma, red parameter dropped but stayed higher than the modern value (a*=0), the CaCO3 percentage difference between Site 1148 from a lower deepwater setting and Site 1146 from an upper deepwater setting enlarged significantly, and benthic species which prefer oxygen-rich bottom conditions dramatically decreased. Coupled with a major negative excursion of benthic δ13C at ~10 Ma,these parameters may denote a weakening in the control of the SCS deep water by the open ocean.Probably they mark the birth of a local deep water due to shallow waterways or rise of sill depths during the course of sea basin closing from south to east by the west-moving Philippine Arc after the end of SCS seafloor spreading at 16-15 Ma. However, it took another 5 Ma before the dissolved oxygen approached close to the modern level. Although the oxygen level continued to stabilize, several Pacific Bottom Water (PBW) and Pacific Deep Water (PDW) marker species rapidly increased since ~6 Ma,followed by a dramatic escalation in planktonic fragmentation which indicates high dissolution especially after ~5 Ma. The period of 5-3 Ma saw the strongest stratified deepwater in the then SCS, as indicated by up to 40% CaCO3 difference between Sites 1148 and 1146. Apart from a strengthening PDW as a result of global cooling and ice

  6. Implications of IODP Expedition 349 Age Results for the Spreading History of the South China Sea

    Science.gov (United States)

    Briais, Anne

    2016-04-01

    The International Ocean Discovery Program (IODP) Expedition 349 in the South China Sea drilled three sites (U1431, U1433, and U1434) into the basaltic crustal basement near the fossil spreading center in the East and Southwest Subbasins. These results provided age constraints on the termination of seafloor spreading in the South China Sea (SCS) basin. Shipboard biostratigraphic analysis of microfossils from the sediment immediately above or between flows in the basaltic basement indicates early Miocene ages: 16.7-17.6 Ma for Site U1431 in the East Subbasin, ~18-21 Ma for Site U1433 in the Southwest Subbasin. Since Expedition 349, Ar/Ar dating of basalt samples from these two sites have confirmed these ages in the east, and have provided an age of 17 Ma in the Southwest. The similarity in crustal age between sites suggests that the last stages of spreading have been coeaval in both the East and Southwest Subbasins, forming a single mid-ocean ridge system with a series of transform faults and discontinuities between the two subbasins. Expedition 349 also drilled Site U1435 on a bathymetric high along the northwestern continent-ocean boundary. Onboard core description, biostratigraphy and magnetostratigraphy revealed that sediment at this site shows a sharp discontinuity at about 33 Ma, interpreted to represent the breakup unconformity and date the beginning of seafloor spreading in the East Subbasin. The results of IODP Exp. 349, as well as results from deep-towed magnetic surveys, thus imply that oceanic seafloor spreading in the SCS, from 33 to ~16-18 Ma, is coeval with a large part of the left-lateral motion along the Ailao Shan-Red River Fault Zone (dated 34 to 17 Ma). This episode of the extension of the South China Sea basin is therefore more likely driven by the extrusion of the Indochina tectonic block resulting from the collision of India with Eurasia than by the subduction of a proto-South China Sea to the south.

  7. Geochemical evolution of groundwater salinity at basin scale: a case study from Datong basin, Northern China.

    Science.gov (United States)

    Wu, Ya; Wang, Yanxin

    2014-05-01

    A hydrogeochemical investigation using integrated methods of stable isotopes ((18)O, (2)H), (87)Sr/(86)Sr ratios, Cl/Br ratios, chloride-mass balance, mass balance and hydrogeochemical modeling was conducted to interpret the geochemical evolution of groundwater salinity in Datong basin, northern China. The δ(2)H, δ(18)O ratios in precipitation exhibited a local meteoric water line of δ(2)H = 6.4 δ(18)O -5 (R(2) = 0.94), while those in groundwater suggested their meteoric origin in a historically colder climatic regime with a speculated recharge rate of less than 20.5 mm overall per year, in addition to recharge from a component of deep residual ancient lake water enriched with Br. According to the Sr isotope binary mixing model, the mixing of recharges from the Shentou karst springs (24%), the western margins (11%) and the eastern margins (65%) accounts for the groundwater from the deep aquifers of the down-gradient parts in the central basin is a possible mixing mechanism. In Datong, hydrolysis of silicate minerals is the most important hydrogeochemical process responsible for groundwater chemistry, in addition to dissolution of carbonate and evaporites. In the recharge areas, silicate chemical weathering is typically at the bisiallitization stage, while that in the central basin is mostly at the monosiallitization stage with limited evidence of being in equilibrium with gibbsite. Na exchange with bound Ca, Mg prevails at basin scale, and intensifies with groundwater salinity, while Ca, Mg exchange with bound Na locally occurs in the east pluvial and alluvial plains. Although groundwater salinity increases with the progress of water-rock/sediment interactions along the flow path, as a result of carbonate solubility control and continuous evapotranspiration, Na-HCO3 and Na-Cl-SO4 types of water are usually characterized respectively in the deep and the shallow aquifers of an inland basin with a silicate terrain in an arid climatic regime.

  8. Seismic stratigraphy of the Qiongdongnan deep sea channel system, northwest South China Sea

    Institute of Scientific and Technical Information of China (English)

    YUAN Shengqiang; L(U) Fuliang; WU Shiguo; YAO Genshun; MA Yubo; FU Yanhui

    2009-01-01

    Based on more than 4000 km 2D seismic data and seismic stratigraphic analysis, we discussed the extent and formation mechanism of the Qiongdongnan deep sea channel. The Qiongdongnan deep sea channel is a large incised channel which extends from the east boundary of the Yinggehai Basin, through the whole Qiongdongnan and the Xisha trough, and terminates in the western part of the northwest subbasin of South China Sea. It is more than 570 km long and 4-8 km wide. The chaotic (or continuous) middle (or high) amplitude, middle (or high) continuity seismic facies of the channel reflect the different lithological distribution of the channel. The channel formed as a complex result of global sea level drop during early Piiocene, large scale of sediment supply to the Yinggehai Basin, inversion event of the Red River strike-slip fault, and tilted direction of the Qiongdongnan Basin. The large scale of sediment supply from Red River caused the shelf break of the Yinggehai Basin to move torwards the S and SE direction and developed large scale of prograding wedge from the Miocene, and the inversion of the Red River strike-slip fault induced the sediment slump which formed the Qiongdongnan deep sea channel.

  9. Accumulation and exploration of gas hydrate in deep-sea sediments of northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guangxue; CHEN Fang; YANG Shengxiong; SU Xin; SHA Zhibin; WANG Hongbin; LIANG Jinqiang; ZHOU Yang

    2012-01-01

    The large deep-sea area from the southwestern Qiongdongnan Basin to the eastern Dongsha Islands,within the continental margin of northern South China Sea,is a frontier of natural gas hydrate exploration in China.Multiform of deep-sea sedimentations have been occurred since late Miocene,and sediment waves as a potential quality reservoir of natural gas hydrate is an most important style of them.Based on abundant available data of seismic,gravity sampling and drilling core,we analyzed the characteristics of seismic reflection and sedimentation of sediment waves and the occurrence of naturat gas hydrate hosted in it,and discussed the control factors on natural gas hydrate accumulation.The former findings revealed the deep sea of the northern South China Sea have superior geological conditions on natural gas hydrate accumulation.Therefore,it will be of great significance in deep-sea natural gas hydrate exploration with the study on the relationship between deep-sea sedimentation and natural gas hydrate accumulation.

  10. Geological conditions of coal and gas(oil)-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    WANG Tingbin

    2005-01-01

    There are various types of coal basins in China. Indosinian movement can be regarded as their evolutionary limit, and the basins can be divided into two developmental stages, three structural patterns and two sedimentary environments. However, only those coal measure strata that have been deeply buried in the earth are possible to be converted into coal and gas (oil)-bearing basins. Among which, only part of the coal measures possess the essential geological conditions to the formation of commercial humic oil. However, humic gas will be the major exploration target for natural gas in China. Among various coal basins, foreland basins have the best prospect for humic gas. Rift (faulted) basins accumulate the most abundance of humic gas, and are most favorable to generate humic oil. Craton basins have relatively low abundance of humic gas, but the evolution is rather great. The three kinds of coal basins mentioned above constitute China's three primary accumulation areas of humic gas: western, central and offshore areas. The major basins for humic gas field exploration include Tarim, Ordos, Sichuan, East China Sea and Yingqiong basins.

  11. Hydrological Characteristics of the Heihe River Basin in the Arid Inland Area of Northwest China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The hydrological characteristics of the Heihe River Basin in the arid inland area of northwest China were investigated.The spatial distribution of annual precipitation in the basin indicates that it decreases from east to west and from south to north,and increases with elevation by a gradient of 24.4 mm per hundred meters below 2,810 m a.s.l.,but decreases with elevation by that of 37.0 mm per hundred meters above 2,810 m a.s.l.For the last 50 years,the mountain runoff of the ba-sin has a tendency of increase.Except in the mountain area,the aridity is very high in the basin,and the aridity index ranges from 1.6 to 7.0 at the piedmont,to 9.0~20.0 in the midstream area and up to 40.0 in the downstream Ejin region.It is estimated for the last 50 years that a 1oC increment of annual temperature causes a 21.5 mm increase of evaporation in the mountain area,and the equivalent reduction of mountain runoff is 0.215×109 m3/yr at the Yingluoxia Hydrometric Sta-tion.The estimation shows also that a 1oC increment of annual temperature causes 1,842 mm increase of farmland evapotranspiration in the midstream area,an equivalent of 0.298×109 m3/yr more water consumption.The anthropogenic influence on the hydrological processes and water resources is then discussed.

  12. Spatiotemporal Assessment of Groundwater Resources in the South Platte Basin, Colorado

    Science.gov (United States)

    Ruybal, C. J.; McCray, J. E.; Hogue, T. S.

    2015-12-01

    The South Platte Basin is one of the most economically diverse and fastest growing basins in Colorado. Strong competition for water resources in an over-appropriated system brings challenges to meeting future water demands. Balancing the conjunctive use of surface water and groundwater from the South Platte alluvial aquifer and the Denver Basin aquifer system is critical for meeting future demands. Over the past decade, energy development in the basin has added to the competition for water resources, highlighting the need to advance our understanding of the availability and sustainability of groundwater resources. Current work includes evaluating groundwater storage changes and recharge regimes throughout the South Platte Basin under competing uses, e.g. agriculture, oil and gas, urban, recreational, and environmental. The Gravity Recovery and Climate Experiment satellites in conjunction with existing groundwater data is used to evaluate spatiotemporal variability in groundwater storage and identify areas of high water stress. Spatiotemporal data will also be utilized to develop a high resolution groundwater model of the region. Results will ultimately help stakeholders in the South Platte Basin better understand groundwater resource challenges and contribute to Colorado's strategic future water planning.

  13. Detecting changes in future precipitation extremes over eight river basins in China using RegCM4 downscaling

    Science.gov (United States)

    Qin, Peihua; Xie, Zhenghui

    2016-06-01

    To detect the frequency and intensity of precipitation extremes in China for the middle 21st century, simulations were conducted with the regional climate model RegCM4 forced by the global climate model GFDL_ESM2M under the middle emission scenario (RCP4.5). Compared with observed precipitation extremes for the reference period from 1982 to 2001, RegCM4 generally performed better in most river basins of China relative to GFDL. In the future period 2032-2051, more wet extremes will occur relative to the present period in most study areas, especially in southeast China while significantly less dry extremes will occur in arid and semiarid areas in northwest China. In contrast, areas in northwest China showed an increase in the trend of dry extremes (CDD) and a decrease in the trend of wet extremes (R95p and Rx5day), which might result in more drought in the future. Finally, we discuss in detail the possible reason of these processes, such as zonal wind, vertical wind, and water vapor. In the Huaihe river basin (HU), reduced south winds in summer (June-August) and a decrease of the upward vertical p velocity cause less future precipitation and might lead to changes of extreme events. We also completed correlation analysis between the precipitation extreme indices and the climate factors and found that the precipitation extremes were more sensitive to the annual and seasonal mean precipitation, total water vapor, and upward vertical wind relative to the geopotential height and 2 m temperature over most river basins in China. Perhaps the changes of some wet extremes could be verified partly through changes of annual precipitation due to their high consistence.

  14. Modern pollen rain in the Lake Qinghai basin, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Lake Qinghai is the largest inland brackish lake in China and lies within the NE Tibetan Plateau. Our study shows that pollen assemblages in each vegetation belt are significantly correlated with the vegetation types of this area. Among the herbaceous and shrubby pollen assemblages, Artemisia is over-represented, while Poaceae, Cyperaceae and Polygonaceae are under-represented. Artemisia/ Chenopodiaceae (A/C) ratios with the regional vegetation characteristic can be used as a proper index to reconstruct the history of vegetation and climate in Lake Qinghai basin. Modern pollen in the lake mainly comes from the nearby vegetation, controlled by the directions and velocity of the wind. The distribution of modern pollen in Lake Qinghai tends to be similar in most part of the lake. The difference of pollen sedimentation process in the lake can be potentially influenced by the focusing function of the lake, river streams, and lake current.

  15. Sample Return Mission to the South Pole Aitken Basin

    Science.gov (United States)

    Duke, M. B.; Clark, B. C.; Gamber, T.; Lucey, P. G.; Ryder, G.; Taylor, G. J.

    1999-01-01

    The South Pole Aitken Basin (SPA) is the largest and oldest observed feature on the Moon. Compositional and topographic data from Galileo, Clementine, and Lunar Prospector have demonstrated that SPA represents a distinctive major lunar terrane, which has not been sampled either by sample return missions (Apollo, Luna) or by lunar meteorites. The floor of SPA is characterized by mafic compositions enriched in Fe, Ti, and Th in comparison to its surroundings. This composition may represent melt rocks from the SPA event, which would be mixtures of the preexisting crust and mantle rocks. However, the Fe content is higher than expected, and the large Apollo basin, within SPA, exposes deeper material with lower iron content. Some of the Fe enrichment may represent mare and cryptomare deposits. No model adequately accounts for all of the characteristics of the SPA and disagreements are fundamental. Is mantle material exposed or contained as fragments in melt rock and breccias? If impact melt is present, did the vast sheet differentiate? Was the initial mantle and crust compositionally different from other regions of the Moon? Was the impact event somehow peculiar, (e.g., a low-velocity impact)? The precise time of formation of the SPA is unknown, being limited only by the initial differentiation of the Moon and the age of the Imbrium event, believed to be 3.9 b.y. The questions raised by the SPA can be addressed only with detailed sample analysis. Analysis of the melt rocks, fragments in breccias, and basalts of SPA can address several highly significant problems for the Moon and the history of the solar system. The time of formation of SPA, based on analysis of melt rocks formed in the event. would put limits on the period of intense bombardment of the Moon, which has been inferred by some to include a "terminal cataclysm." If close to 3.9 Ga, the presumed age of the Imbrium Basin, the SPA date would confirm the lunar cataclysm. This episode, if it occurred, would have

  16. Does China and Africa South-South cooperation lead to economic development in Africa?

    Directory of Open Access Journals (Sweden)

    Nonfodji, P.

    2013-03-01

    Full Text Available Since a few decades now Chinese enterprises’ investments abroad have seen a continuous and steady ascension. At first cautious and just across the Chinese national borders, these investments, slowly but surely, spread like a sheet of water that seeps into the heart of each continent on the globe. This global infiltration of Chinese companies coincides with the popularity in the use of the expression “South-South Cooperation” to characterize a type of relations between countries categorized as being “developing”. Accordingly this paper seeks to examine the role of the use of this concept as a “channel to achieve common development” in the context of Chinese enterprises’ outward direct investments in Africa adopting insights from international business production theories combined with an historical analysis of the notion of South-South Cooperation. Drawing on primary data gathered during my fieldwork in China in the period stretching from December 2011 to February 2012 and secondary data sources, it is argued that these Chinese investments supported by the Chinese government rhetoric on South-South cooperation, cannot lead to significant economic development in Africa like it has happened in China in the eighties. Rather and at most Chinese investments in Africa show some “trickle-down” effects characterised by very limited economic development in scattered localities throughout the African continent.

  17. Numerical simulation of rifting controlled by magmatic underplating in the South China Sea

    Science.gov (United States)

    Xu, Hehua

    2016-04-01

    South China Sea is one of the largest basins in the western Pacific marginal sea, which is located in the intersection area of the Eurasia, the India-Australian and the Pacific-Philippines plate. Although the duration of seafloor spreading and the extension mechanism are still controversial.It is widely accepted that the South China Sea was opened by seafloor spreading in the Cenozoic. From the point of its structural development history, South China Sea has its own unique development model, which is formed by the continent rifting and expansion, while the tectonic evolution has close relationship with geological peripheral units. According to the seismic detection and magnetic integrated geophysics, the studies found that high-speed lower crust layers are widespread in the northern South China Sea and the northeast of continental margin, these layers are mainly located in continental slopes and some high-degree tensional continental shelves. Researches suggested that materials of high-speed in lower crustal layers are formed by the bottom magmatic underplating rather than serpentinized mantle peridotite. These layers are formed in Cenozoic and has close relationship with extension. However, in most kinematic and dynamic models of rift formation and evolution, the effects of magmatism have been neglected. This study established a two-dimensional thermal - mechanical coupled finite element model to simulate the role of underplated magmatic bodies in the localization of deformation. We examine the response of the lithosphere to an applied constant boundary velocity at the edge of the model. The mamatic underplating is introduced as a material with an anomalous high temperture and a magic upper mantle composition. The mechanical problem is coupled with the thermal problem through temperature-dependent viscosity. Since extension of lithosphere and underlying mantle is associated with intense and simultaneous viscous and brittle/plastic(faulting) deformations, we use

  18. Typical basin-fill sequences and basin migration in Yanshan, North China--Response to Mesozoic tectonic transition

    Institute of Scientific and Technical Information of China (English)

    LI; Zhong; LIU; Shaofeng; ZHANG; Jinfang; WANG; Qingchen

    2004-01-01

    Basin-fill sequences of Mesozoic typical basins in the Yanshan area, North China may be divided into four phases, reflecting lithosphere tectonic evolution from flexure (T3), flexure with weak rifting (J1+2), tectonic transition (J3), and rifting (K). Except the first phase, the other three phases all start with lava and volcaniclastic rocks, and end with thick coarse clastic rocks and/or conglomerates, showing cyclic basin development rather than simple cyclic rift mechanism and disciplinary basin-stress change from extension to compression in each phase. Prototype basin analysis, based on basin-fill sequences, paleocurrent distribution and depositional systems, shows that single basin-strike and structural-line direction controlling basin development had evidently changed from east-west to northeast in Late Jurassic in the Yanshan area, although basin group still occurred in east-west zonal distribution. Till Early Cretaceous, main structural-line strike controlling basins just turned to northeast by north in the studied area.

  19. Relating petroleum system and play development to basin evolution: West African South Atlantic basins

    NARCIS (Netherlands)

    Beglinger, S.E.; Doust, H.; Cloetingh, S.A.P.L.

    2012-01-01

    Sedimentary basins can be classified according to their structural genesis and evolutionary history and the latter can be linked to petroleumsystem and playdevelopment. We propose an approach in which we use the established concepts in a new way: breaking basins down into their natural basin cycle d

  20. Climate analysis of evaporation ducts in the South China Sea

    OpenAIRE

    McKeon, Brian D.

    2013-01-01

    Approved for public release; distribution is unlimited. Evaporation ducts have important implications for U.S. Naval activities involving electromagnetic propagation. The presence of an evaporation duct can affect naval operations involving communications, surveillance, electronic warfare, and detection of low-flying missiles, surface ships, or submarine periscopes. We conducted a climate scale analysis of evaporation duct heights (EDH) in the northern South China Sea (SCS), including how ...

  1. Pork Preference for Consumers in China, Japan and South Korea

    OpenAIRE

    Oh, S.-H.; See, M. T.

    2012-01-01

    Competition in global pork markets has increased as trade barriers have opened as a result of free trade agreements. Japanese prefer both loin and Boston butt, while Chinese prefer pork offal. Frozen pork has increased in terms of imports into China. Japanese consumers consider pork meat origin along with pork price when making purchase decisions. While the Chinese prefer a strong tasting pork product, South Korean consumers show very strong preferences to pork that is higher in fat. Therefor...

  2. Sustainable development of agriculture in karst areas, South China

    OpenAIRE

    Linhua Song

    1999-01-01

    The exposed carbonate rocks aged from Sinian to Mid-Triassic Periods cover an area of 500,000 Km2 in south-west China. In karst areas with spectacular landscapes characterized by magnificent tower karst and conical karst, rare surface drainage systems and prevalent subsurface drainage systems, the environment is ecologically very fragile. The rapid increase of population, over deforested and cultivated lands, worsted the ecological system, causing a higher frequency of draught, flood and vari...

  3. Fourth China-South Asia International Cultural Forum

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>The Fourth China-South Asia International Cultural Forum on "revitalizing people-to-people cultural exchanges for peace and prosperity",co-sponsored by the CPAFFC and Shenzhen University,was held in Shenzhen from November 14 to 17,2012. More than 60 experts and scholars from over 40 Chinese research institutes and their colleagues from India,the United States and Singapore engaged in in-depth discussions on economic cooperation and cultural development,the present condi-

  4. Scientific questions about South China Sea ocean dynamics

    Institute of Scientific and Technical Information of China (English)

    HUANG Rui Xin; DU Yan

    2015-01-01

    South China Sea, its circulation and connection with other parts of the world oceans, poses important scientific questions. From the prospective view, we postulate ten key research directions to be pursued in the coming future, including ventilation of a monsoon dominated sea, water mass formation/transformation, heat/salt and water mass balance, energetics and mixing, mesoscale eddies, the role of typhoon, deep circulation and paleoclimate records, interaction with adjacent oceans, upwelling and ecology system, and response to climate changes.

  5. Summary of The 3 South China Cardiovascular Scientific Sessions

    Institute of Scientific and Technical Information of China (English)

    刘伊丽; 曾冲

    2001-01-01

    @@The 3rd South China Cardiovascular Scientific Sessions was held on August 4th ~ 6th, 2001 in Guangzhou.There were a total of 119 papers published, 13 lectures given by well- known cardiologists from inland and other parts of the world and 13 satellite conferences.These sessions were characterized by abundant updated information and advance in research on cardiovascular diseases in basic and clinical sciences. They are summarized as follows:

  6. 78 FR 65706 - Ferrovanadium From China and South Africa; Institution of Five-Year Reviews

    Science.gov (United States)

    2013-11-01

    ... imports of ferrovanadium from China and South Africa (73 FR 77609). The Commission is now conducting... and South Africa (68 FR 4168 and 4169). Following the first five-year reviews by Commerce and the... COMMISSION Ferrovanadium From China and South Africa; Institution of Five- Year Reviews AGENCY: United...

  7. Modal Wave Number Tomography for South China Sea Front

    Institute of Scientific and Technical Information of China (English)

    彭临慧; 王宁; 邱晓芳; 田纪伟

    2003-01-01

    Monitoring of the South China Sea is always one of the focuses in the field of ocean engineering for its particular geographic position. The modal wave number tomography is proposed for monitoring the front and numerical simulation is performed for the front of the South China Sea. With the empirical orthonormal function (EOF) applied to reduce the parameter search space, the perturbation inversion method is used for inversing sound speed profiles. The 2-D ocean environment used for numerical simulation is selected from the ocean area, located in 20°N, 118°E~20°N, 125°E, near the Luzon Strait in the South China Sea. The ocean environment sound speed distribution in the ocean area under study is obtained from the assimilation of multi-source remote sensing data. The numerical simulation shows that the modal wave number tomography can inverse the average sound speed profile, therefore,it can be used to monitor ocean internal structures such as ocean fronts and eddies which affect sound speed distribution.

  8. Geomagnetic Polarity Reversal Model of Deeptow Magnetic Survey in the Southwest Subbasin of South China Sea Ridge

    Science.gov (United States)

    Qiu, N.; Sun, Z.; Lin, J.; Li, C. F.; Xu, X.

    2014-12-01

    South China Sea basin, which evolved from Cenozoic continental margin rifting and subsequent seafloor spreading, is a classic example of a marginal sea in Western Pacific. Since the early 1980's, several models have been proposed for the formation of this sea basin. The previous studies were based mainly on the distribution of magnetic anomaly lineation obtained from aerial and shipboard measurements. However, large water depth (over 4.5km) and thick sediment cover (up to 1km or more) make the magnetic anoamaly information not so well displayed in aerial and shipboard data. To better understand the evolution of the sea basin, we increased anomaly amplitudes by collecting magnetic data along deep-tow profiles over the magnetic lineations in the South China Sea oceanic area. The one across the southwest subsea basin was analyzed first. The total field magnetic measurements were processed through filtering, resampling, diurnal variation removal, continuation to a level datum, regional field correction, projection to a common azimuth, and deskewing. A magnetic polarity reversal timescale was constructed by matching deep-tow anomalies with a simple, rectangular block magnetization model with the expansion rate for oceanic crust. We analyzed the spreading duration, rate, asymmetry, and reversal events of Southwest subbasin, in reference to the recent GTS2012 geomagnetic polarity representative data and concluded that the Southwest subbasin opened from around 21.767 Ma and stopped around C5C at about 15.974Ma. The full spreading rate varied from 8 to 40 cm/yr. Spreading is usually asymmetric by showing alternate faster spreading rate in one slab than the other in different time periods. From the comparison, several small reversal were revealed in addition to the standard geomagnetic polarity. These findings helped to understand the evolution of the Southwest subbasin of South China Sea and will also help to establish new reversal discrimination.

  9. Beyond water, beyond boundaries: spaces of water management in the Krishna river basin, South India.

    Science.gov (United States)

    Venot, Jean-Philippe; Bharati, Luna; Giordano, Mark; Molle, François

    2011-01-01

    As demand and competition for water resources increase, the river basin has become the primary unit for water management and planning. While appealing in principle, practical implementation of river basin management and allocation has often been problematic. This paper examines the case of the Krishna basin in South India. It highlights that conflicts over basin water are embedded in a broad reality of planning and development where multiple scales of decisionmaking and non-water issues are at play. While this defines the river basin as a disputed "space of dependence", the river basin has yet to acquire a social reality. It is not yet a "space of engagement" in and for which multiple actors take actions. This explains the endurance of an interstate dispute over the sharing of the Krishna waters and sets limits to what can be achieved through further basin water allocation and adjudication mechanisms – tribunals – that are too narrowly defined. There is a need to extend the domain of negotiation from that of a single river basin to multiple scales and to non-water sectors. Institutional arrangements for basin management need to internalise the political spaces of the Indian polity: the states and the panchayats. This re-scaling process is more likely to shape the river basin as a space of engagement in which partial agreements can be iteratively renegotiated, and constitute a promising alternative to the current interstate stalemate.

  10. Radiometric dating of uranium mineralization in the proterozoic basins of Eastern Dharwar Craton, South India

    International Nuclear Information System (INIS)

    Results of radiometric dating by Pb and Sm-Nd isotopic systematics on uranium bearing rocks within the Proterozoic basins of the Eastern Dharwar craton in parts of Andhra Pradesh and Karnataka, South India are discussed. The results indicate three main periods of uranium mineralization and remobilization events at c. 1.70-1.80 Ga, c. 1.25-1.35 Ga and 0.45-0.55 Ga in these basins. (author)

  11. Seasonal variation of black carbon over the South China Sea and in various continental locations in South China

    Directory of Open Access Journals (Sweden)

    D. Wu

    2013-07-01

    Full Text Available Black carbon (BC is an important atmospheric constitute as an air pollutant and as a climate forcer. To our knowledge, field measurements of BC have not been reported over the South China Sea. Observation of light absorption coefficients (σabs and BC concentrations by Aethalometer were conducted on Yongxing Island in the South China Sea and at five continental sites in the Pearl River Delta (PRD region, South China during the South China Sea monsoon period (rainy season, 16 May–20 June 2008 and the northeast monsoon period (dry season, 12 December 2008–8 January 2009. At the oceanic site, the daily average BC concentrations vary from 0.28 to 2.14 μg m−3 and seasonal variations of BC were small (0.67 in dry season and 0.54 μg m−3 in rainy season. Similarly, little seasonal difference was found at a background site in PRD (2.88 in dry season and 2.62 μg m−3 in rainy season. At PRD urban sites, the daily average concentration of BC ranges from 1.56 to 37.9 μg m−3, higher in the dry season (12.6 μg m−3 and lower in the rainy season (6.4 μg m−3. The observed average σabs values in rainy vs. dry seasons are 119 vs. 62 Mm−1 at the PRD urban sites, 29 vs. 26 Mm−1 at the PRD background site, and 8.4 vs. 7.2 Mm−1 at the marine site. A bi-peak pattern in diurnal BC variation was observed at all sites while this pattern is the most prominent at the urban sites. The first peak appears in the early morning rush hour and the second peak in early evening, with the evening peak more pronounced in dry season.

  12. The coral grayness in northern South China Sea and its description of interdecadal variation of precipitation in south China

    Institute of Scientific and Technical Information of China (English)

    GU Dejun; WANG Dongxiao; SUN Donghuai; GAO Rongzhen; JI Zhongping

    2006-01-01

    The interdecadal variation of coral grayness in northern South China Sea (SCS) is studied using the annual mean coral grayness in northern SCS from 1789 to 1992 and annual precipitation at Guangzhou from 1908 to 1992 by Singular Spectrum Analysis (SSA), correlation analysis, Mann-Kendall's abrupt change analysis and composite analysis. The interdecadal variation of south China precipitation as reflected by the series of Guangzhou precipitation rebuilt with the coral grayness is discussed. The results show that the variation of coral grayness in SCS has significant terms of tendency, much-weighted interdecadal variation and weak interannual variation.There was a century-scale abrupt change of coral grayness at the end of the 1880s that changed from positive anomalies to negative anomalies. The global field of SST difference corresponding to the point of abrupt change was negative anomalies over the SCS and neighboring northern Indian Ocean, most of central and western Pacific Ocean and coastal areas of the northern Atlantic Ocean. The large-scale distribution of SST anomalies is concomitant with the century-scale abrupt change of coral grayness in SCS. Negative correlation exists between the coral grayness in SCS and precipitation in Guangzhou on the interdecadal scale and the interdecadal precipitation in Guangzhou as reflected by the interdecadal data of SCS coral grayness shows that the interdecadal variation of south China precipitation changes significantly from phase to phase. The current study aims at contributing in the effort of identifying alternative indexes for climate change in south China on the interdecadal scale and beyond.

  13. An integrated multiscale river basin observing system in the Heihe River Basin, northwest China

    Science.gov (United States)

    Li, X.; Liu, S.; Xiao, Q.; Ma, M.; Jin, R.; Che, T.

    2015-12-01

    Using the watershed as the unit to establish an integrated watershed observing system has been an important trend in integrated eco-hydrologic studies in the past ten years. Thus far, a relatively comprehensive watershed observing system has been established in the Heihe River Basin, northwest China. In addition, two comprehensive remote sensing hydrology experiments have been conducted sequentially in the Heihe River Basin, including the Watershed Allied Telemetry Experimental Research (WATER) (2007-2010) and the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) (2012-2015). Among these two experiments, an important result of WATER has been the generation of some multi-scale, high-quality comprehensive datasets, which have greatly supported the development, improvement and validation of a series of ecological, hydrological and quantitative remote-sensing models. The goal of a breakthrough for solving the "data bottleneck" problem has been achieved. HiWATER was initiated in 2012. This project has established a world-class hydrological and meteorological observation network, a flux measurement matrix and an eco-hydrological wireless sensor network. A set of super high-resolution airborne remote-sensing data has also been obtained. In addition, there has been important progress with regard to the scaling research. Furthermore, the automatic acquisition, transmission, quality control and remote control of the observational data has been realized through the use of wireless sensor network technology. The observation and information systems have been highly integrated, which will provide a solid foundation for establishing a research platform that integrates observation, data management, model simulation, scenario analysis and decision-making support to foster 21st-century watershed science in China.

  14. Distribution of the East China Sea continental shelf basins and depths of magnetic sources

    OpenAIRE

    Lin, Jing-yi; Sibuet, Jean-claude; Hsu, S.

    2005-01-01

    The acoustic basement map of the East China Sea, established by the Shanghai Offshore Petroleum Bureau with all available industry seismic data, shows the existence of a 30-km-wide, 10-km-deep basin, that we named the Ho Basin. The Ho Basin belongs to a series of elongated deep basins extending over 600 km east of the Taiwan-Sinzi Ridge and flanked to the East by a ridge named the Longwan Ridge in its northern part. This new system of basin and ridge was probably formed during middle Miocene,...

  15. Assessment of Paleozoic shale gas resources in the Sichuan Basin of China, 2015

    Science.gov (United States)

    Potter, Christopher J.; Schenk, Christopher J.; Charpentier, Ronald R.; Gaswirth, Stephanie B.; Klett, Timothy R.; Leathers, Heidi M.; Brownfield, Michael E.; Mercier, Tracey J.; Tennyson, Marilyn E.; Pitman, Janet K.

    2015-10-14

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 23.9 trillion cubic feet of technically recoverable shale gas resources in Paleozoic formations in the Sichuan Basin of China.

  16. No Red River capture since the late Oligocene: Geochemical evidence from the Northwestern South China Sea

    Science.gov (United States)

    Zhao, Meng; Shao, Lei; Liang, Jianshe; Li, Qianyu

    2015-12-01

    Rare earth elements (REE) in the sediment samples of six industrial wells from the Yinggehai-Song Hong Basin in the Northwestern South China Sea were analyzed and compared with the detrital zircon U-Pb data from earlier studies to extrapolate sediment provenance. The results reveal that the Red River (Song Hong River), Hainan Island and Central Vietnam have been the main provenances of the Yinggehai-Song Hong Basin since the late Oligocene. The Red River has been supplying sediments with positive Eu anomalies from basic-ultrabasic metamorphic and volcanic parent rocks to most parts of the basin, while Hainan Island has delivered sediments with negative Eu anomalies from granitic and sedimentary parent rocks to the eastern slope area of the basin. The progradational downlap structures in the seismic profiles also support the finding that the sediment supply is mainly from the Red River and from Hainan Island. The metamorphic rocks, which are widespread within the Red River drainage, not only provided high volumes of sediments to the basin but also contributed to the positive Eu anomalies observed. Because their REE and U-Pb signatures are similar to those of the Red River source, the metamorphic and igneous rocks of the Song Ma Suture Zone, Kontum Massif, and Jinghong area were probably parts of a large basic provenance region before being separated by strike-slip movements along the Ailao Shan-Red River shear zone. Furthermore, our results indicate that the Red River drainage area has been relatively stable since the late Oligocene. Therefore, if a drainage capture from the Red River occurred, it is likely to have taken place before the late Oligocene.

  17. Effects of Kuroshio intrusions on nonlinear internal waves in the South China Sea during winter

    Science.gov (United States)

    Park, Jae-Hun; Farmer, David

    2013-12-01

    During winter the Kuroshio tends to cross Luzon Strait, penetrating the northeastern South China Sea where it forms energetic mesoscale structures. Luzon Strait is also a site where westward-propagating large-amplitude internal waves are generated. We describe observations of these waves acquired in the deep basin of the South China Sea during the winter of 2010-2011, with the goal of assessing the influence of mesoscale variability on their properties. Combining tidal current simulations with an internal wave generation and evolution model, we obtain time series of deviations between our observations and the model simulations. These deviations are analyzed in terms of mesoscale variability based on the data-assimilated HYbrid Coordinate Ocean Model (HYCOM) simulations. We find that simplified models of nonlinear internal wave response to changes in horizontal stratification gradients and vertical shear provide at best weak simulations of amplitude modulation. In contrast to these results, deviations of internal wave arrival time, occurring up to 2 h early during Kuroshio inflows, are quite well simulated when derived from integration of the first internal mode phase speed along two-dimensional ray-traced paths using HYCOM simulations of velocity and density fields together with bathymetry. Refraction of the internal waves by Kuroshio intrusions can lead to substantial distortion of the paths, sufficient to provide a potential explanation for the apparent suppression of waves during previous winter measurements. Our results suggest that the internal wave field can be a sensitive indicator of mesoscale variability in Luzon Strait and the northeastern South China Sea.

  18. The Oceanic Crustal Structure of the Southwestern Subbasin in the South China Sea

    Science.gov (United States)

    Wu, Z.; Ruan, A.; Li, J.; Lee, C.

    2012-12-01

    Located at the southwestern part of the South China Sea (SCS) among the Zhongsha Islands(Macclesfield Bank), the east subbasin, the Nansha Islands(Dangerous Ground), the V type southwest subbasin (SWSB) is an unique ocean basin in all the three subbasins of SCS. The crustal structure is one of the key problems to study the formation and evolution of SWSB. During December 2010 to March 2011, Ocean Bottom Seismometers (OBSs) experiment has been carried out in the SWSB to get the deep crustal structure information, especially under the fossil spreading center. Three types of OBS, Sedis IV type, I-4C type and MicrOBS type have been used in the experiment, and the energy source was supplied by 6000 inch3 large volume air-gun. High quality seismic data of four 2D profiles which covered the fossil spreading center of SWSB have been acquired. The data of the experiment can supply evidence for the study of oceanic crustal structure of the SWSB and seafloor spreading course, etc. The profile 1 extended 130 km in length. A total of 8 OBSs were deployed at intervals of 10 or 15 km and 7 OBSs were recovered. The data of the 7 stations of profile 1 have been processed, which shows that the seismic records are clear and seismic phases are abundance, and the air-guns have enough energy supply. The velocity model was obtained by using an interactive trial-and-error 2D ray-tracing method. The crustal structure indicates that the crustal thickness under the SWSB is about 6 km, and the moho depth is about 10km. The results reveal that the crust of SWSB is normal oceanic crust with a thin sedimentary layer on the seamount and shallow moho surface. The crustal velocity under the spreading center is extremely low, which shows the characteristic of the deep crustal structure of the fossil spreading center. Acknowledgements This study was supported by the National Natural Science Foundation of China (Grant No. 91028006, 41106053, 41176046), Scientific Research Fund of the Second Institute

  19. A New System of Marginal Arc in the North of the South China Sea of Today

    Science.gov (United States)

    Fang, N.; Dong, H.; Zhao, H.; Liu, H.; Shen, P.; Liang, X.

    2014-12-01

    SubFac, and (5) the Cretaceous volcano-sedimentary sequences representing back-arc rifting and outcropping in the Nanxiong and Hengyang basins, South China. The above pattern portrays an active margin characterized by subducting northward to the Asian land and disappearing at the end of the Mesozoic, which should be a part of the Tethyan archipelago.

  20. Oligocene biogenic siliceous deposits on the slope of the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The abundance of radiolarian, diatom and sponge spicule and H4SiO4 in pore-waters increase abruptly at the boundary between Early and Late Oligocene (about 30-27.5 Ma) at Site 1148 of the northern South China Sea (SCS), indicating high biogenic silica accumulation during this time. At the same time (about 30-28 Ma), high biogenic silica deposition occurred in the cen tral equatorial Pacific. Comparison of the biogenic silica accumulation at Site 1148 of the SCS with that at Site 929 of the Atlantic verifies that the biogenic silica accumulation between the low lati tude Pacific and Atlantic oceans expresses the evident relationship of compensation during theOligocene. Biogenic silica accumulation decreased in the Atlantic, whereas it increased in the Pa cific at the boundary between the Early and Late Oligocene. It resulted from the formation and presence of North Atlantic deep water (NADW) in the Atlantic basin, indicating an intensive basin-basin fractionation. XRD analysis and SEM observation of the samples from Site 1148 demon strate that most of radiolarian, diatom and sponge spicule have suffered from dissolution and reprecipitation, suggested by the opal-A→opal-CT transformation. As a result of the transformation,porosity increased, but dry and bulk densities decreased, reflecting the consequence of diagenesis on the physical property of sediment.

  1. Alternative Water Allocation in Kyrgyzstan: Lessons from the Lower Colorado River Basin and New South Wales

    Directory of Open Access Journals (Sweden)

    Nazir Mirzaev

    2010-08-01

    Full Text Available Focus group discussions and a modeling approach were applied to determine policy and regulatory refinements for current water allocation practices in Kyrgyzstan. Lessons from the Lower Colorado River basin, Texas and New South Wales, Australia were taken into consideration. The paper analyzes the impact of adopting some of these interventions within the socio-environmental context that currently prevails in Kyrgyzstan. The optimization model for water distribution at the river-basin scale was developed using GAMS 2.25 software. Application of the model to the Akbura River basin indicated efficiencies in the proposed institutional rules especially in low water years.

  2. The effects of China entering the World Trade Organization on the South Korean telecommunication industry

    OpenAIRE

    Conner, William J.

    2003-01-01

    This thesis investigates the effects of China entering the World Trade Organization on the South Korean wireless telecommunication industry. Of particular interest, this thesis explores whether the South Korean wireless telecom industry will benefit from China's accession into the WTO. The working hypothesis of the thesis is that South Korean wireless telecom companies will receive far-reaching economic benefit from China's entry into the WTO. Additionally, this thesis explores the effec...

  3. Correction of OBS Position and Recent Advances of 3D Seismic Exploration in the Central Sub-Basin of South China Sea%南海中央次海盆OBS位置校正及三维地震探测新进展

    Institute of Scientific and Technical Information of China (English)

    张莉; 赵明辉; 王建; 贺恩远; 敖威; 丘学林; 徐辉龙; 卫小冬; 张佳政

    2013-01-01

    南海中央次海盆首次开展的三维海底地震仪(ocean bottom seismometer,OBS)探测试验,对于全面认识南海扩张脊处速度展布特征及海底扩张历史有着重要意义.海底地震仪的位置是研究三维地震结构的关键参数之一,高精度的三维OBS数据处理,决定着后期地震结构反演模型的分辨率与准确性.利用直达水波走时信息,综合最小二乘法反演原理,并采用蒙特卡罗法模拟OBS降落海底的过程,完成了南海中央次海盆试验区39台OBS数据格式转换与位置校正工作;同时探讨了蒙特卡罗法应用于位置校正的精度问题.处理后OBS综合记录剖面中展示了多组清晰可靠、来自珍贝-黄岩火山链下深部结构中的P波震相,如Pg、PmP和Pn震相,为下一步南海中央次海盆的三维层析成像奠定了坚实数据基础.%A three-dimensional (3D) Ocean Bottom Seismometer (OBS) seismic exploration is implemented for the first time in the central sub-basin of South China Sea (SCS). The velocity distribution in 3D high spatial variability is significant to understand the history of expansion and evolution of SCS. However, high-precision 3D data processing determines the resolution and accuracy for the further seismic structure, where OBS position is one of the key parameters in seismic structural study. We use the travel time data of direct water waves to simulate the process of OBS landing on seafloor employing the least squares method and Monte Carlo method. Finally the corrections of OBS positions have been achieved for a total of 39 OBSs in the central sub-basin of SCS experiment. Meanwhile the accuracy of Monte Carlo method for relocation has been discussed. A few clear and reliable P-wave seismic phases, such as Pg, PmP and Pn, were discovered in the OBS seismic record sections, which come from deep crust or upper mantle beneath the Zhenbei-Huangyan volcanic chains. These abundant seismic phases provide a strong data

  4. Inter-annual sea level variability in the southern South China Sea

    Science.gov (United States)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    2015-10-01

    The South China Sea (SCS) is the largest marginal sea in the western Pacific Basin. Sea level anomalies (SLAs) in the southern South China Sea (SSCS) are assumed to be governed by various phenomena associated with the adjacent parts of the Indian Ocean and the Pacific Ocean. We have used monthly sea level anomalies obtained from 12 tide gauge stations of PSMSL and UHSLC and merged and gridded AVISO products of SLAs (sea level anomalies) derived from satellite altimeter. We find that IOD-influenced inter-annual variations are found only in the southwestern and southeastern coastal regions of SSCS. Our analysis reveals that inter-annual regional sea level drops are associated with positive phase of the IOD, and the rises with negative phase of the IOD. SLA variations at decadal scale in the southeastern and northern Gulf of Thailand correlate with Pacific Decadal Oscillations (PDO). Multiple linear regression analysis of inter-annual SLAs and climate indices shows that IOD induced inter-annual variations dominate in the southwestern SCS and it contributes to about ~ 40% of inter-annual sea level variation. Meanwhile, ENSO contributes to around ~ 30% variation in sea level in the southwestern and ~ 40% variation in the southeastern SSCS. The present study also suggests that inter-annual SLA variations in the SSCS can occur by ENSO and IOD induced changes in wind stress curl and volume transport variations.

  5. Characteristics of the Geotectonics in South China and Their Constraints on Primary Diamond

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Asian continent is one of the best places in the world to study continental dynamics. In this region the tectonic framework of the South China plate is related to the activity of the Pacific plate and Indian plate since the Mesozoic. In the South China plate, as the ophiolitic mélange of the middle Proterozoic in the Shaoxing-Yingtan-Tengxian-Beihai faulted zone was confirmed to be a subducting ocean, the evolution of the Yangtze block and Cathaysian block, which are located on both sides of the fault zone, becomes clearer and clearer. A primary diamond deposit, which was first found by Bao Chaomin and his colleagues in Longyou County of Zhejiang Province in 1998, originated from kimberlitoid pipes. The pipes are located in the Cretaceous basin beside this deep fault and the diamond-bearing pipe was formed deep within a favourable geological structure. Diamond there occurs as octahedral crystals without visual impurities. There are more than 100 similar pipes in the area, which have been poorly studied so far, so this area should have great prospects for diamond exploration.

  6. Assessment of Climate Change Effects on Water Resources in the Yellow River Basin, China

    OpenAIRE

    Zhiyong Wu; Heng Xiao; Guihua Lu; Jinming Chen

    2015-01-01

    The water resources in the Yellow River basin (YRB) are vital to social and economic development in North and Northwest China. The basin has a marked continental monsoon climate and its water resources are especially vulnerable to climate change. Projected runoff in the basin for the period from 2001 to 2030 was simulated using the variable infiltration capacity (VIC) macroscale hydrology model. VIC was first calibrated using observations and then was driven by the precipitation and temperat...

  7. Responses of thermal structure and vertical dynamic structure of South China Sea to Typhoon Chanchu

    Institute of Scientific and Technical Information of China (English)

    陈宜展; 詹杰民; 罗莹莹; 唐灵; 韦永康

    2014-01-01

    The response of the South China Sea (SCS) to Typhoon Chanchu (2006) was examined using the MM5 and POM model. In the POM model, sea surface boundary conditions were forced by the simulation wind field from MM5, the velocity forcing was introduced in the eastern boundary and the computational schemes of heat fluxes at the surface were introduced. Comparison with the observation data shows that the simulated results are reliable. In the response process of the SCS to Typhoon Chanchu, the influence of the heat fluxes on thermal structure of the SCS was regionally different. Strong wind forcing would lead to upwelling phenomenon in the lateral boundary of deep water basin. Furthermore, the Ekman pumping theory was used to discuss subsurface upwelling and downwelling phenomenon in typhoon forced stage.

  8. Chinese assertiveness in the South China Sea and Southeast Asian responses

    OpenAIRE

    Thayer, Carlyle A.

    2011-01-01

    This article reviews Chinese assertive behaviour towards the Philippines and Vietnam over South China Sea issues in 2011. The article compares and contrasts Chinese diplomatic behaviour in the period before and after the adoption by ASEAN member states and China of Guidelines for the Implementation the Declaration on Conduct of Parties in the South China Sea in July. In the first period China aggressively asserted its claims to sovereignty by interfering with commercial fishing and oil explor...

  9. Continental tectonics and uranium province of South China

    International Nuclear Information System (INIS)

    The pre-Sinian metamorphic basement of South China consists of 4 blocks, namely the Jiangnan, the Wuyi, the Yunkai-South Sea and the Mintai which belong to the same lithospheric plate from late Proterozoic on. The plate is enriched in U and Th revealed by Pb-isotopic study, which plays an role of essential prerequisite for the formation of U province. The amalgamation of the 4 blocks and their final attachment to Yangtze craton were resulted from Proterozoic, Caledonian, Indonesia and Yangshanian orogenic events, driven by Moho-rheologic stratification so that uraniferous black rock sequences and U-hosting granites and volcanics in age from late Sinian to Jurassic were produced in the fore lands of corresponding major orogenic uplifts. The change of tectonic regime from compression-relaxed to lateral tension happened after significant crust's thickening and large-scale emplacement of granitic batholiths during late Triassic and early Jurassic though local compression occurred from middle Eocene to Oligocene. Most of U deposits were just formed in association with this para-cratonization process from late Jurassic to Eogene. South China GGT shows that there exist the thinning and the break-up of undercrustal lithosphere at the Datian and the Quanzhou and funnel-shaped seg at middle Hunan. The former two are considered to be the product of up-migration of hot mantle plume and the latter to be the place of down-migration of cold mantle plume

  10. Position of South China in configuration of Neoproterozoic supercontinent

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yongfei

    2004-01-01

    @@ Configuration and evolution of Neoproterozoic supercontinent and the position of South China within it have been very important targets in earth sciences concerningmany forefront topics of general interest. In the commonreconstruction of the supercontinent Rodinia, South Chinawas located between Australia and Laurentia, and thus liesin the center of the supercontinent and southeast of Aus-tralia[1]. According to the new paleomagnetic and geo-chronological data for the ~800 Ma Xiaofeng dyke in Yichang as well as existing data, Li et al.[2] suggest that Rodinia would probably spread from the equator to the polar region at about 800 Ma, followed by a rapid ca. 90( rotation around an axis near Greenland that brought the entire supercontinent to a low-latitude position by ca. 750 Ma. As a result, South China is reinterpreted to be placed adjacent to both Australia and India, with a rapid shift of rotation from a position northeast of Australia and southeast of India at about 800 Ma (Fig. 1(a)) to a position northwest of Australia and northeast of India at about 750 Ma (Fig. 1(b)).

  11. Abiogenic hydrocarbons in commercial gases from the Songliao Basin, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha- nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode- gradation of complex high-molecule sedimentary organic material can form microbial gas or thermogenic gas. The δ 13C1 value ranges from -110‰ to -50‰ for microbial gases but from -50‰ to -35‰ (even heavier) for thermogenic gases. Controlled by the kinetic isotope fractionation, both microbial and thermogenic gases have δ 13C and δ D values characterized by normal distribution, i.e. δ 13C1< δ 13C2< δ 13C3< δ 13C4 and δ DCH4< δ DC2H6< δ DC3H8<δ DC4H10, and by a positive correlation between the δ 13C and δ D values. Simple carbonbearing molecules (CH4, CO and CO2) can form abiogenic alkane gases via polymerization in the abiological chemical process in nature, with δ 13C1 heavier than -30‰. Moreover, controlled by the kinetic isotope fractionation, abiogenic alkane gases are characterized by a reverse distribution of δ 13C values and a normal trend of δ D values, namely δ 13C1> δ 13C2> δ 13C3> δ 13C4 and δ DCH4<δ DC2H6< δ DC3H8< δ DC4H10. The δ 13C values and δ D values are negatively correlated. Natural gases from 26 commercial gas wells distributed in the Xujiaweizi and Yingshan-Miaotaizi faulted depressions in the Songliao Basin, China, show δ13C1 values ranging from -30.5‰ to -16.7‰ with a very narrow δ D range between -203‰―-196‰. These gases are characterized by a reverse distribution of δ 13C values but a normal distribution of δ D values, and a negative correlation between their δ 13C and δ D values, indicating an abiological origin. The present study has revealed that abiogenic hydrocarbons not only exist in nature but also can make significant contribution to commercial gas reserviors. It is estimated that

  12. Abiogenic hydrocarbons in commercial gases from the Songliao Basin, China

    Institute of Scientific and Technical Information of China (English)

    WANG XianBin; WANG LianSheng; LIU ChunXue; YAN Hong; LI LiWu; ZHOU XiaoFeng; WANG YongLi; YANG Hui; WANG Guang; GUO ZhanQian; TUO JinCai; GUO HongYan; LI ZhenXi; ZHUO ShengGuang; JIANG HongLiang; ZENG LongWei; ZHANG MingJie

    2009-01-01

    This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha-nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode-gradation of complex high-molecule sedimentary organic material can form microbial gas or ther-mogenic gas. The δ13C1 value ranges from -110‰ to -50‰ for microbial gases but from -51‰ to -35‰ (even heavier) for thermogenic gases. Controlled by the kinetic isotope fractionation, both microbial and thermogenic gases have δ13C and δD values characterized by normal distribution, i.e. δ13C1 δ13C2> δ13C3> δ13C4 and δDCH4<δDC2H6< δDC3H8< δDC4H10. The δ13C values and δD values are negatively correlated. Natural gases from 26 commercial gas wells distributed in the Xujiaweizi and Yingshan-Miaotaizi faulted de-pressions in the Songliao Basin, China, show δ13C1 values ranging from -30.5‰. to -16.7‰, with a very narrow δD range between -203‰--196‰. These gases are characterized by a reverse distribution of δ13C values but a normal distribution of δD values, and a negative correlation between their δ13C and δD values, indicating an abiological origin. The present study has revealed that abiogenic hydrocar-bons not only exist in nature but also can make significant contribution to commercial gas reserviors. It is estimated that the reserve volume of alkane gases with abiogenic characteristics in these 26 gas wells in the Songliao Basin is over 500×108 m3, The prospecting practice in the Songliao Basin has demonstrated that abiogenic alkane gases are of a promising resource, and it provides an example for the investigation of and search for abiogenic commercial natural gases worldwide.

  13. Origin and Distribution of Hydrogen Sulfide in Oil-Bearing Basins, China

    Institute of Scientific and Technical Information of China (English)

    ZHU Guangyou; ZHANG Shuichang; LIANG Yingbo

    2009-01-01

    The concentration of hydrogen sulfide gas (H_2S) varies greatly in the oil-bearing basins of China, from zero to 90%. At present, oil and gas reservoirs with high H_2S concentration have been discovered in three basins, viz. the Bohai Bay Basin, Sichuan Basin and the Tarim Basin, whereas natural gas with low H_2S concentration has been found in the Ordos Basin, the Songiiao Basin and the Junggar Basin. Studies suggest that in China H_2S origin types are very complex. In the carbonate reservoir of the Sichuan Basin, the Ordos Basin and the Tarim Basin, as well as the carbonate-dominated reservoir in the Luojia area of the Jiyang depression in the Bohai Bay Basin, Wumaying areas of the Huanghua depression, and Zhaolanzhuang areas of the Jizhong depression, the H_2S is of Thermochemical Sulfate Reduction (TSR) origin. The H_2S is of Bacterial Sulphate Reduction (BSR) origin deduced from the waterflooding operation in the Changheng Oiifieid (placanticline oil fields) in the Songliao Basin. H_2S originates from thermal decomposition of sulfur-bearing crude oil in the heavy oil area in the Junggar Basin and in the Liaohe heavy oil steam pilot area in the western depression of the Bohai Bay Basin. The origin types are most complex, including TSR and thermal decomposition of sulfcompounds among other combinations of causes. Various methods have been tried to identify the origin mechanism and to predict the distribution of H_2S. The origin identification methods for H_2S mainly comprise sulfur and carbon isotopes, reservoir petrology, particular biomarkers, and petroleum geology integrated technologies; using a combination of these applications can allow the accurate identification of the origins of H_2S. The prediction technologies for primary and secondary origin of H_2S have been set up separately.

  14. 一南海问题与中国南部地缘安全%The South China Sea Issue and Geo-security in the South China

    Institute of Scientific and Technical Information of China (English)

    李国选

    2014-01-01

    冷战后,南海的地缘位置与地缘环境决定了南海的价值。然而,南海问题的存在深刻地影响着南海地区的和平与发展,特别是对中国南部的地缘安全的制约作用日益明显。南海问题使中国不能有效地维护中国在南海的海域安全,不能有力地保证中国的战略航道安全,并且阻碍中国南部地缘环境的持续改善。中国应采取必要的对策消除南海问题对中国南部地缘安全的制约作用。%After the Cold War, the geopolitical location and geopolitical environment of the South China Sea determines the value of the South China Sea. However, the existence of the South China Sea dispute has a profound impact on peace and development in the South China Sea region, especially on China’s south geo-security. The South China Sea dispute makes China not effectively protect maritime security in the South China Sea, not effectually ensure the security of China’s strategic waterways and impede the geopolitical environment in southern China to improve continuously. China should take necessary measures to eliminate the negative effect that the South China Sea dispute has on China’s geo-security.

  15. Crustal Rheology and Rifted Margin Architecture: Comparing Iberia-Newfoundland, Central South Atlantic, and South China Sea

    Science.gov (United States)

    Brune, Sascha

    2015-04-01

    migration of the rift centre, which generates sequential fault activity within the brittle crust. Rift migration results from two processes: (i) Strain hardening takes place in the rift centre due to cooling of upwelling mantle material. (ii) The formation of a low viscosity crustal pocket adjacent to the rift centre is caused by heat transfer from the mantle and viscous strain softening of the lower crust. These mechanisms generate a lateral strength contrast that promotes rift migration in a steady-state manner forming a wide sliver of hyper-extended crust on one margins side, while the conjugate margin becomes narrow. In contrast to these Atlantic examples where wide margins are formed diachronously, the South China Sea evolved in wide rift mode. Here, several hundred kilometres of highly attenuated continental crust are deformed simultaneously during ~40 My of extension. Numerical modelling suggests that the presence of weak, ductile crust enabled the formation of two wide and symmetric margins. Independent indicators for a weak crust come from super-deep basins on the northern margin. These basins appear to be created after the end of active extension and with a significant deficit in brittle faulting, which suggests that subsidence was controlled by sediment loading and accommodated by lower crustal flow, a style of basin formation that is only possible in the presence of low crustal viscosity.

  16. Lateral fluid flow in a compacting sand-shale sequence: South Caspian basin.

    Science.gov (United States)

    Bredehoeft, J.D.; Djevanshir, R.D.; Belitz, K.R.

    1988-01-01

    The South Caspian basin contains both sands and shales that have pore-fluid pressures substantially in excess of hydrostatic fluid pressure. Pore-pressure data from the South Caspian basin demonstrate that large differences in excess hydraulic head exist between sand and shale. The data indicate that sands are acting as drains for overlying and underlying compacting shales and that fluid flows laterally through the sand on a regional scale from the basin interior northward to points of discharge. The major driving force for the fluid movement is shale compaction. We present a first- order mathematical analysis in an effort to test if the permeability of the sands required to support a regional flow system is reasonable. The results of the analysis suggest regional sand permeabilities ranging from 1 to 30 md; a range that seems reasonable. This result supports the thesis that lateral fluid flow is occurring on a regional scale within the South Caspian basin. If vertical conduits for flow exist within the basin, they are sufficiently impermeable and do not provide a major outlet for the regional flow system. The lateral fluid flow within the sands implies that the stratigraphic sequence is divided into horizontal units that are hydraulically isolated from one another, a conclusion that has important implications for oil and gas migration.-Authors

  17. Hydrogeochemical and isotopic investigations of the Han River basin, South Korea

    Science.gov (United States)

    Ryu, Jong-Sik; Lee, Kwang-Sik; Chang, Ho-Wan

    2007-10-01

    SummaryThe Han River, the largest river in South Korea draining approximately 26,000 km 2, comprises two major tributaries: the North and the South Han Rivers. Seasonal and spatial variations in the major ion chemistry and isotope compositions of the Han River were monitored for one year at 14-23 locations, covering about 80% of the entire drainage basin. Compared to the South Han River (SHR), the North Han River (NHR) was much lower in total dissolved solids (TDS), Sr, and major ion concentrations, but higher in Si concentration, δ 34S SO 4 values, and 87Sr/ 86Sr ratios. These observations suggest strong influence of prevailing rock types in the drainage basins on the chemical and isotopic compositions of the river waters. These are silicate rocks in the NHR basin and carbonate rocks in the SHR basin. The headwaters of the NHR basin, where several flood control dams have been constructed, show enrichment in deuterium and oxygen-18, indicating evaporative loss. The δ 34S SO 4 data suggest dissolved sulfates in the NHR and SHR are mostly derived from atmospheric deposition, and variable mixtures of atmospheric deposition and sulfide oxidation, respectively. The 87Sr/ 86Sr ratios are much higher in the NHR (0.71793-0.72722) than in the SHR (0.71495-0.71785) with one exception, indicating weathering of Precambrian and Mesozoic granitic rocks and marine carbonates, respectively.

  18. Thermicity and fluid flow related to the evolution of the South Pyrenean Foreland Basin (SPFB)

    Science.gov (United States)

    Crognier, Nemo; Hoareau, Guilhem; Lacroix, Brice; Aubourg, Charles; Dubois, Michel; Lahfid, Abdeltif; Labaume, Pierre; Suarez-Ruiz, Isabel

    2015-04-01

    The East-West trending South Pyrenean Foreland Basin (SPFB), formed during the upper Cretaceous and the early Miocene due to the collision between Iberian and European plates, is filled by marine to continental deposits affected by a set of successive southvergent thrusts. In the western part of the SPFB (Jaca basin, Spain), from the North to the South the basin is subdivided into four parts: the internal Sierras, the turbiditic basin, the molassic basin and the external Sierras. In order to better constrain the fluid flow dynamic and the thermal regime of the basin during its tectonic evolution, we propose to estimate the temperatures and the O and C isotopic signatures of fluids, as well as the maximum temperatures recorded by pre- to syn-tectonic sediments of the Jaca basin. The C and O isotopic composition has been measured on ~100 veins and host sediment samples. The peak temperatures have also been estimated on 80 bulk rocks and calcite/quartz veins using a combination of several techniques, including Raman Spectroscopy of Carbonaceous Material, vitrinite reflectance, fluid inclusion microthermometry and mass-47 clumped isotopes. We show that in most tectonic fractures, primary fluid inclusions are characterized by moderate salinities (~2.5 wt%) compatible with connate or evolved meteoric waters, with increasing meteoric signature in the south of the basin. As suggested by temperature determinations and stable isotopes, involved fluids were generally in thermal and isotopic equilibrium with the host sediments, suggesting a low fluid-rock ratio (i.e., no significant fluid flow). These results support previous speculations of moderate fluid-flow through thrust faults and the hydrological compartmentalization of the Jaca basin during deformation (Lacroix et al., 2014). In addition we demonstrate that measured peak temperatures rapidly decrease southward, from ~240°C±30°C in Cretaceous to Eocene sediments located in the North of the basin close to the axial

  19. Identifying entry points to improve fertilizer use efficiency in Taihu Basin, China

    NARCIS (Netherlands)

    Ma, Li; Feng, S.; Reidsma, P.; Qu, F.; Heerink, N.

    2014-01-01

    Overuse of fertilizers in China causes environmental problems and high costs for farmers. In this paper we aim to identify entry points to improve fertilizer use efficiency in Taihu Basin, China. We use stochastic frontier analysis to estimate the technical and fertilizer use efficiency of rice prod

  20. 75 FR 61414 - Basin Electric Power Cooperative: South Dakota PrairieWinds Project

    Science.gov (United States)

    2010-10-05

    ...) for the Environmental Impact Statement (EIS) for the proposed South Dakota PrairieWind Project... purpose of the EIS was to evaluate the potential environmental impacts of and alternatives to Basin... 151.5-megawatt (MW) nameplate capacity wind-powered energy generation facility that would feature...

  1. Precipitation variability assessment of northeast China: Songhua River basin

    Indian Academy of Sciences (India)

    Muhammad Imran Khan; Dong Liu; Qiang Fu; Muhammad Azmat; Mingjie Luo; Yuxiang Hu; Yongjia Zhang; Faiz M Abrar

    2016-07-01

    Variability in precipitation is critical for the management of water resources. In this study, the researchentropy base concept was applied to investigate spatial and temporal variability of the precipitationduring 1964–2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy wasapplied on precipitation data on a monthly, seasonally, annually, decade scale and the number of rainydays for each selected station. Intensity entropy and apportionment entropy were used to calculate thevariability over individual year and decade, respectively. Subsequently, Spearman’s Rho and Mann–Kendall tests were applied to observe for trends in the precipitation time series. The statistics of sampledisorder index showed that the precipitation during February (mean 1.09, max. 1.26 and min. 0.80),April (mean 1.12, max. 1.29 and min. 0.99) and July (mean 1.10, max. 1.20 and min. 0.98) contributedsignificantly higher than those of other months. Overall, the contribution of the winter season wasconsiderably high with a standard deviation of 0.10. The precipitation variability on decade basis wasobserved to increase from decade 1964–1973 and 1994–2003 with a mean value of decadal apportionmentdisorder index 0.023 and 0.053, respectively. In addition, the Mann–Kendall test value (1.90) showed asignificant positive trend only at the Shangzhi station.

  2. Precipitation variability assessment of northeast China: Songhua River basin

    Science.gov (United States)

    Khan, Muhammad Imran; Liu, Dong; Fu, Qiang; Azmat, Muhammad; Luo, Mingjie; Hu, Yuxiang; Zhang, Yongjia; Abrar, Faiz M.

    2016-07-01

    Variability in precipitation is critical for the management of water resources. In this study, the research entropy base concept was applied to investigate spatial and temporal variability of the precipitation during 1964-2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy was applied on precipitation data on a monthly, seasonally, annually, decade scale and the number of rainy days for each selected station. Intensity entropy and apportionment entropy were used to calculate the variability over individual year and decade, respectively. Subsequently, Spearman's Rho and Mann-Kendall tests were applied to observe for trends in the precipitation time series. The statistics of sample disorder index showed that the precipitation during February (mean 1.09, max. 1.26 and min. 0.80), April (mean 1.12, max. 1.29 and min. 0.99) and July (mean 1.10, max. 1.20 and min. 0.98) contributed significantly higher than those of other months. Overall, the contribution of the winter season was considerably high with a standard deviation of 0.10. The precipitation variability on decade basis was observed to increase from decade 1964-1973 and 1994-2003 with a mean value of decadal apportionment disorder index 0.023 and 0.053, respectively. In addition, the Mann-Kendall test value (1.90) showed a significant positive trend only at the Shangzhi station.

  3. Origin of Natural Gas in Kekeya Field, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    Hou Dujie; Xiao Zhongyao; Tang Youjun; Zhu Junzhang; Li Xianqing

    2004-01-01

    This paper is mainly concentrated on the geochemical characteristics and origin of gas of Kekeya field in the Tarim basin, NW China. This study shows that Permian mudstone is the main source rock of oil and gas. Based on the carbon isotopes of C1-C4, the carbon isotope of gas in Kekeya field is a little heavier than that in the typical marine-derived gas. The relationship between carbon isotopes of methane and ethane is coincident with Faber equation of gas derived from organic matter Ⅰ/Ⅱ. The majority of gas maturity is estimated, based on the formula, at 1.8 %-2.2 % besides K2 and K18 wells. In addition, the gas derived from 0.9 %-1.2 % Ro source rocks may also be mixture. 40Ar/36Ar and 3He/4He ratios from the gas samples also support the mixing process. Moreover, the gas in this region is mainly generated from more mature source rocks although the low mature gas exists.

  4. Octoradiate Spiral Organisms in the Ediacaran of South China

    Institute of Scientific and Technical Information of China (English)

    TANG Feng; YIN Chongyu; Stefan BENGTSON; LIU Pengju; WANG Ziqiang; GAO Linzhi

    2008-01-01

    Shales of the Ediacaran Doushantuo Formation of South China contain a new disc-shaped macrofossil, Eoandromeda octobrachiata, characterized by eight spiral arms that were probably housed within an outer membrane. Although the presence of eight radiating structures entails a resemblance to cnidarian octocorais as well as to ctenophores, direct homologies with these extant groups are unlikely. Instead we bring attention to the helicospiral morphology of newly reported embryos from the Doushantuo Formation, suggesting that the long-sought adults of the Ediacaran embryonic metazoans have fmaily been found.

  5. Management pattern of ecological public welfare forests in South China

    Institute of Scientific and Technical Information of China (English)

    Chong LOU; Anxing LIU; Guomin ZHU

    2008-01-01

    The characteristics and actualities of ecologi-cal public welfare forests in South China are studied in this paper, including common and special management patterns. The restoration and reconstruction pattern of subtropical evergreen broad-leaved forests, zonal vegeta-tion in the key eco-zone, and the transformation pattern of coniferous and broad-leaved mixed forests in the general eco-zone with multi-forms are discussed in detail. The authors also point out, based on ecological transformation and utilization, that ecological public welfare forests should be oriented to multiple benefit utilization to maintain sustainable management.

  6. THE CLIMATE FEATURES OF THE SOUTH CHINA SEA WARM POOL

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There exists a warm pool in the South China Sea (SCS). The temporal and spatial distribution and evolution of SCS warm pool is investigated using water temperatures at a depth of 20 m in the sea. The formation of the warm pool is discussed by combining water temperatures with geostrophic currents and simulated oceanic circulation. It is found that there are significant seasonal and interannual changes in the warm pool and in association with the general circulation of the atmosphere. The development of SCS warm pool is also closely related to the gyre activities in the sea and imported warm water from Indian Ocean (Java Sea) besides radiative warming.

  7. Study on the Late Permian Claraia in South China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There are different opinions on whether Claraia appeared in the Late Permian or not. Itis convinced that Claraia had turned up in the Late Permian through the study on the Upper Per-mian in South China. Pseudoclaraia, Claraioides and Claraia are compared and they are found tobear basically the same features. According to the rule of nomenclatural priority, Pseudoclaraiaand Claraioides should be attributed to the genus Claraia. Late Permian Claraia lived in the mid-dle-lower part of the bathyal continental slope as epifauna, which could swim occasionally. Thestudy on Claraia of the Permian-Triassic transition shows that Triassic Claraia was evolved fromPermian Claraia

  8. South China's Gondwana connection in the Paleozoic:Paleomagnetic evidence

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shihong

    2004-01-01

    The reconstruction in which the South China Block (SCB) lies along the Great India-Australia region of Gondwana margin is tested by using existing Paleozoic paleomagnetic data.Under the proposed reconstruction, all six high quality paleopoles from the SCB between the Early Cambrian and late Early Devonian (~400 Ma) are in good agreement with coeval paleopoles from Gondwana.Thereafter, the apparent polar wander paths for the SCB and Gondwana diverge markedly.This indicates that the SCB had been part of Gondwana and the connection was intact from at least Early Cambrian until late Early Devonian, but they began to separate by late Middle Devonian (~375 Ma).

  9. Navigating the Security Dilemma: China, Vietnam, and the South China Sea

    Directory of Open Access Journals (Sweden)

    Jason J. Blazevic

    2012-01-01

    Full Text Available Competition and conflict in the South China Sea involves many nations due to its resources and vital sea lanes. However, it is China which increasingly serves as a common denominator of intensifying anxiety for its South China Sea maritime neighbours due to the aggressive scope of its claims to the sea and its islands. Among those states, Vietnam is most affected as it is first in the path of Chinese ambitions – ambitions which authorities fear would give China significant tactical military and economic advantage. For China, there are similar fears over threats to the sea lanes and sea bed resources. Leaders of both states also perceive their diplomatic and martial actions in the sea in historical terms as well. However, enforcement actions taken by either state may lead to a worsening security dilemma in which reactive security strategies could dangerously destabilise relations. This article discusses the motivations and strategies of both states as well as the consequences of such and applies realism, its tenets of defensive and offensive realism, and neoliberalism to examine their security concerns and perceptions. The article further proposes that the most valuable insights can be provided by defensive realism and neoliberalism, which together can encourage security, cooperation and conciliation in order to best promote the improvement of relations.

  10. Study on the Late Permian Claraia in South China

    Institute of Scientific and Technical Information of China (English)

    YANG; Fengqing

    2001-01-01

    [1]Nakazawa, K., On Claraia of Kashmir and Iran, J. Paleont. Soc. Idia., 1977, 20: 194-204.[2]Kulikov, M. V., Tkachuk, G. A., On finding of Claraia (Bivalvia) in Upper Permian deposits of Northern Caucasus,Doklady Akad. Nauk. USSR, 1979, 245(4): 905-908.[3]Yin. H. F.. Uppermost Permian (Changxingian) Pectinacea from South China, Riv. Ital. Paleont., 1982, 88(3): 337-386.[4]Yin. H. F.. Bivalves near the Permian-Triassic boundary in South China, J. Paleo.,1985, 59(3): 572-600.[5]Yang. Z. Y.. Yin H. F., Wu, S. B. et al., Permian-Triassic Boundary Stratigraphy and Fauna of South China (in Chinese).Geological Memoirs, Ser. 2, No. 6, Beijing: Geological Publishing House, 1987, 56-57, 236-237.[6]Guo. F. X.. Bivalves Fossil of Yunnan (in Chinese), Kunming: Yunnan Technology Press, 1985.[7]Fang. Z. J., Discussion on Late Permian “Claraia”, Act. Palaeo. Sini. (in Chinese),1993, 2(6):653-661.[8]Zhang. Z. M.. Discussion on the ligament structure of Claraia and its evolution, Act. Palaeo. Sini. (in Chinese), 1980,19(6): 433-443.[9]Nanjing Institute of Geology and Paleontology, Academia Sinica, The Bivalves of China (in Chinese), Beijing: Science Press, 1976.[10]Zhou. Z. R.. Two ecological types of Permian Ammonoids, Science in China (in Chinese), Ser. B, 1985, (7): 648-657.[11] Stanley. S. M., Relation of shell form to life habitats of the Bivalvia (Mollusca), Geol. Soc. Amer., 1970, 125: 1-496.[12]Stanley, S. M.. tunctional morphology and evolution of byssally attached bivalve mollusks, J. Paleont, 1972, 46(2): 165-207.[13]Yin, H. F.. Ding, M. H., Zhang, K. X. et al., Late Permian-Middle Triassic Ecostratigraphy of the Yangtze Platform and Its Margins, Beijing: Science Press, 1995, 69-76.[14]Leonardi, E. Trias inferiore delle Venezie, Mem. Inst. Geol. Univ. Padova., 1935, II, 1-136.[15]Ichikawa. K. Zur Taxonomie und Phylogenie der Triadischen Pteriidae (Lamellibranch), Palaeotog., 1958, III, A, 132-212.

  11. Geochronology of and Nd—Sr—Pb Isotopic Evidence for Mantle Source in the Ancient Subduction Zone beneath Sanshui Basin,Guangdong Province,China

    Institute of Scientific and Technical Information of China (English)

    朱炳泉; 蒲志平; 等

    1989-01-01

    The available petrochemical data indicate that volcanic rocks in the Sanshui basin of Guangdong Prov-ince are characteristic of the island-arc tholeiite-calc-alkaline series.Their K-Ar ages range from 43 to 64 Ma,corresponding to Early Tertiary.The Nd-Sr-Pb isotopic correlations give two binary mixing trends,indicating a mixed source of Leiqiong depleted mantle,seawater and altered sediments pertaining to subduction.Our studies have confirmed the existence of an ancient subduction zone beneath the South Chi-na continent,which is considered to have resulted from the suturing of various terrains in southern China.

  12. Distribution of the East China Sea continental shelf basins and depths of magnetic sources

    Science.gov (United States)

    Lin, J.-Y.; Sibuet, J.-C.; Hsu, S.-K.

    2005-11-01

    The acoustic basement map of the East China Sea, established by the Shanghai Offshore Petroleum Bureau with all available industry seismic data, shows the existence of a 30-km-wide, 10-km-deep basin, that we named the Ho Basin. The Ho Basin belongs to a series of elongated deep basins extending over 600 km east of the Taiwan-Sinzi Ridge and flanked to the East by a ridge named the Longwan Ridge in its northern part. This new system of basin and ridge was probably formed during middle Miocene, sometimes in between rifting episodes occurring in the Taipei Basin and Okinawa Trough. It complements the already defined system of five belts of backarc basins and associated arc volcanic ridges in the East China Sea, which are progressively younger from the Mainland China shoreline (late Cretaceous/early Tertiary) to the Okinawa Trough (Present). In order to determine the crustal thickness beneath the East China Sea continental shelf, we used a power spectrum method to calculate the depth of the top (Zt) and the centroid (Zo) of the magnetic basement by fitting a straight line through the high- and low-wave number portions of the power spectrum, respectively. Then, the depth of the base (Zb)is estimated from Zt and Zo. After optimizing the size of the data squares, we demonstrate that, except for basins more than 10 km deep, Zt corresponds to the basement depths and Zb, the depth of the Curie point, to the Moho depth. As wide-angle reflection and refraction data are scarce in the East China Sea, this method provides a way to characterize the crustal thickness of the East China Sea and to compute the theoretical heat flow values.

  13. Natural gas origins of large and medium-scale gas fields in China sedimentary basins

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas.

  14. The opening of the South China Sea revisited with high-density magnetic tracks

    Science.gov (United States)

    Song, T.; Li, C.

    2011-12-01

    Magnetic anomalies bear extremely rich information on Mesozoic and Cenozoic tectonic evolution of the South China Sea(SCS). Through integrated analyses of magnetic, gravity and reflection seismic data, we define the continent-ocean boundary(COB) around the South China Sea continental margin, and find that the COB coincides very well with a transition zone from mostly positive to negative free-air gravity anomalies. This accurate outlining of the COB is critical for better tracing magnetic anomalies induced by the oceanic crust. Models with a single episode of seafloor spreading are inconsistent with the abrupt magnetic contrast between the East and Southwest Sub-basins.Previous efforts in dating the oceanic crust here are based primarily on very limited numbers of magnetic surveys. Here we take advantage of high-density digital magnetic tracks compiled from multiple surveys to enhance magnetic anomalies caused by the shallow basaltic layer via 2D band-pass filtering. This operation effectively reduces short-wavelength noises and suppresses long-wavelength background anomalies due mostly to deep magnetic sources in the lower crust and uppermost mantle. It is recognized that the likely oldest magnetic anomaly near the northern continental margin is C12 according to the magnetic time scale CK95. Near the southern continental margin, magnetic anomalies are less recognizable and the anomaly C12 appears to be missing. These differences show an asymmetrical opening style with respect to the relict spreading center, and the northern part appears to have slightly faster spreading rates than to the south. The magnetic anomalies C8(M1 and M2, ~26 Ma)represent important magnetic boundaries within the oceanic basin, and are possibly related to changes in spreading rates and magmatic intensities. The magnetic evidence for a previously proposed ridge jump after the anomaly C7 is not clear. To accurately estimate the depths to the top of the basalt layer used in magnetic modeling

  15. Paleostress inversion of fault-slip data from the Jurassic to Cretaceous Huangshan Basin and implications for the tectonic evolution of southeastern China

    Science.gov (United States)

    Xu, Xianbing; Tang, Shuai; Lin, Shoufa

    2016-08-01

    Eight paleostress stages are established in the Jurassic-Cretaceous Huangshan Basin based on fault-slip analysis and age estimation. The first six stages correspond to the subduction of the Paleo-Pacific Plate or the northward motion of the Philippine Block along the southeastern active margin of the South China Block: (1) the 169-162 Ma strike-slip regime was caused by westward low-angle subduction of the Paleo-Pacific Plate, which resulted in NNE-striking folds and top-to-the west thrusting along the southeastern margin of the Huangshan Basin; (2) the 156-125 Ma NW-SE extensional regime was triggered by slab break-off of the Paleo-Pacific Plate. This extension led to Early Cretaceous magmatism, deposition of Early Cretaceous sediments and development of normal faults along the northern boundary of the Huangshan Basin; (3) the 125-107 Ma strike-slip regime was induced by the N-S collision between the Philippine and South China blocks. This tectonic event caused the angular unconformity between the Upper and Lower Cretaceous and the inversion of the Early Cretaceous extensional basin; (4) the 105-86 Ma WNW-ESE extensional regime resulted from an off-shore arc jump of the subducted Paleo-Pacific Plate. This extension triggered the deposition of the Late Cretaceous Qiyunshan Formation; (5) the 86-80 Ma strike-slip regime was induced by high-angle subduction of the Pacific Plate after the off-shore arc jump. This event led to regional uplift and an unconformity at the base of the Late Cretaceous Xiaoyan Formation; (6) the 80-36 Ma N-S extensional regime was caused by the extension following the collision between the Philippine and South China blocks, corresponding to the deposition of the Late Cretaceous Xiaoyan Formation. The last two paleostress stages were the consequences of the far-field effect of the India-Asia continent-continent collision to the southwest of the South China Block: (7) the 36-30 Ma strike-slip regime was caused by the India-Asia collision. It

  16. Influence of small river derived sediment on the Northeastern South China Sea sedimentation processes in the last 40 K years

    Science.gov (United States)

    Cheng, Wan-Yen; Lin, Saulwood; Lou, Jiann-Yuh; Wei, Kuo-Yen; Liu, CharShine; Chen, Shing-Li; Wang, Yun-Shuen

    2015-04-01

    Small rivers derived particles are major source of sediment to the ocean in the present time. Small rivers in Taiwan are subjected to fast tectonic activity, high precipitation rate and erosion rate. The combined annual river particle load from small rivers on the Island of Taiwan is higher than that of the Mississippi River. A large fraction of those rivers particle may finding its way into the surrounding seas and ocean, e.g. South China Sea, East China Sea, and the Philippine Sea. Furthermore, due to the nature of particle transportation off rivers from Taiwan were connected by a number of canyon systems close by the river mouth, majority of those river particles were facilitated in delivering and deposited later further into the South China Sea deep basin. The objectives of this study are to understand spatial variations in sedimentation rates and to resolve the temporal differences in sedimentation in the Northeastern South China Sea region, and to evaluate influence of small river particles to the marginal sea. A set of cores was collected in overlying water depth within 1600 - 3300 m for mutilsensor core logging of magnetic susceptibility, density, and porosity. Foraminifera (G. sacculifer, G. conglobatus, O. universa) were picked and AMS C14 analyses for age determination. Grain size, organic carbon, carbonate and biogenic silica content were measured. The results show that large sedimentation rates difference existed in the study area. Earlier studies on sedimentation rate in the region west of our study area were in range of about 10 cm/kyr while our rates are about 20-40 cm/kyr and much higher near Taiwan. Bulk sedimentation rate were higher during the transition period between LGM and Holocene and lower during Holocene. Our results demonstrated that large quantity of particles from small rivers in Taiwan are and were major source of particle and are the dominating factor in controlling sediment deposition in the northeastern South China Sea.

  17. The rift architecture and extensional tectonics of the South China Sea

    Science.gov (United States)

    Cameselle, Alejandra L.; Ranero, César R.; Barckhausen, Udo; Franke, Dieter

    2016-04-01

    Non-volcanic rifted continental margins are classically described as the product of lithospheric stretching and breakup leading to mantle exhumation, and subsequent seafloor spreading. However, recent studies question this model and indicate a wider range of structural evolutions, that challenge the existing model (e.g. Australia-Antarctic Rift System (Direen et al. 2007, 2011); the Tyrrhenian basin (Prada et al., 2014) or the South China Sea (Cameselle et al. 2015)). Rifting in the South China Sea developed from a series of extensional events, from early Eocene to Late Oligocene, resulting in a V-shape oceanic basin affected by the occurrence of several spreading centers, ridges, transform faults and post-spreading volcanism. In recent years, this marginal basin - the largest in East Asia - has increasingly become one of the key sites for the study of rifting and continental break-up. Its relative small size - compared to many classic, Atlantic-type continental margin settings - allows to easily match conjugated rifted margins and its relative youth promotes the preservation of its original nature. To examine the rifting evolution of the South China Sea, we have reprocessed with modern algorithms multichannel seismic profiles acquired during Sonne49 and BGR84 cruises across the three major subbasins: NW, SW and East subbasins. State-of-the-art of processing techniques have been used to increase the signal to noise ratio, including Tau-P and Wiener predictive deconvolution, multiple attenuation by both radon filtering and wave-equation-based surface-related multiple elimination (SRME) and time migration. To complement seismic interpretation, available vintage multichannel seismic data have been reprocessed with a post-stack flow, including Wiener deconvolution, FK-filtering, space and time variant band-pass filter and time migration. The improving quality of the seismic images shows a range of features including post-rift and syn-rift sediments, the structure of

  18. Discussion on marine source rocks thermal evolvement patterns in the Tarim Basin and Sichuan Basin, west China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Taking marine source rocks of lower Paleozoic in the Tarim Basin and Paleozoic ones in the Sichuan Basin as examples, their sedimentation process could be classified into four styles: continuous subsldence with deep sedimentation in early stage, continuous subsidence with deep sedimentation in later stage, that deeply buried-uplift-shallowly buried, and that shallowly buried-uplift-deeply buried.Unlike that in East China, the marine source rocks evolvement patterns did not accord with sedimentation styles one by one in superimposed basins in west China. Taking local geothermal field into account, four types of source rock evolvement patterns were built: that evolved fast in early stage,evolved fast in middle stage, evolved continuously and evolved in multistage. Among them, the 1st pattern contributed little to the present industrial oil pools directly, but paleo-oil reservoirs and gases cracked from crude oils were main exploration targets. Although some gases were found in the 2nd pattern, the scale was not big enough. For the 3rd and 4th patterns, the hydrocarbon potential depended on organic matters maturity in early stage. For relatively low mature rocks, it was possible to generate some oils in later stage; otherwise the main products were gases. Paleo-oil reservoirs remained fairly well in the Sichuan Basin, and most source rocks underwent kerogen-oil-gas processes,which was useful reference to gas exploration in the Tarim Basin.

  19. A Exploration Project Management of New-Area in South China,CNPC,Found in Hangzhou

    Institute of Scientific and Technical Information of China (English)

    Xia Wenhua

    1994-01-01

    @@ In order to speed up oil-gas exploration in new-area in South China, the Exploration Bureau,CNPC,has decided to set up a New Exploration Project Management in New-Area,South China(EPMNSC.)Its assignments are as follows:

  20. Brief Understanding of the South China Sea Intermittent Line and China’s Relations With Its Neighbors Surrounding the South China Sea

    Institute of Scientific and Technical Information of China (English)

    Hou; Yi

    2014-01-01

    <正>I,Formation of the South China Sea"Intermittent Line"According to historical records,as early as the Qin and Han dynasties,Chinese people began sailing activities onto the Oceans.With the ongoing maritime activities,and improved shipbuilding technology and expanded fishing,the Chinese people in the Han Dynasty first discovered the islands in the South China Sea,

  1. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China

    Science.gov (United States)

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-07-01

    Springtime rainfall, accounting for 25-40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China.

  2. China and South Korea,A Close Economic Connection Leading to Mutual Strategic Cooperation

    Institute of Scientific and Technical Information of China (English)

    Guo Yan

    2008-01-01

    2008 marks the 16th anniversary of this diplomatic bilateral relationship.In recent years,economic trade be- tween China and South Korea has increased greatly,with an improved complementary structure.Now,China is the largest importer of South Ko- rean products.In 1988,South Korea hosted the Olympic Games successfully,and after 20 years,another Asia country—China,hosted the 29th Olympic Games.Before the Beijing 2008 Olympic Games,China's Foreign Trade had the opportunity to interview H.E.Mr.Shin Jung- seu...

  3. Discussion on the Neoproterozoic glaciations in the South China Block and their related paleolatitudes

    Institute of Scientific and Technical Information of China (English)

    ZHANG QiRui; CHU XueLei; FENG LianJun

    2009-01-01

    The Kaigas, Sturtian, Marinoan, and Gaskiers glaciations are widely recognized in Neoproterozoic. However, in the South China Block only the Jiangkou (Sturtian) and Nantuo (Marinoan) are symbolized by sedimentary records. The Kaigas, recorded by isotopic and chemical proxies, exhibited likely the nature of cold paleoclimate with local mountain glaciation. The correlation of the Doushantuo Forma-tion with the Gaskiers is indicated by the carbon isotope excursion and the dated age from the interval, however the South China Block was then under non-glacial weather. With no paleomagnetic data, the position of the South China Block during the Sturtian glaciation cannot be determined. The paleolati-tudes of the South China Block during the Kaigas and Nantuo glaciations are intermediate, even though the Nantuo was once rendered erratically deduced equatorial. In fact, the paleolatitudes of the South China Block during the Neoproterozoic glaciations are all likely at about 30°-40°.

  4. PRELIMINARY STUDY OF RELATIONSHIP BETWEEN INTERANNUAL VARIATIONS OF SST IN SOUTH CHINA SEA AND TROPICAL INDIAN OCEAN AND SOUTH CHINA SEA MONSOON OUTBREAK

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Conclusions are divided regarding the role of the variations of thermodynamics in the monsoon activity for the South China Sea region. In this study, primary eigenvectors are studied for the SSTA from East Asia to the tropical eastern Indian Ocean in May. The results show that temperature anomalies that center on Sumatra are closely related with the outbreak of the South China Sea monsoon. When the SST is warmer (cooler) than average year, it is likely that the monsoon set in late (early). It may be caused by the changes in meridional difference in thermodynamics between the Indochina Peninsula and its southern tropical oceans. Studying the temporal and spatial evolution of primary eigenvector distribution of the SSTA in the South China Sea-tropical eastern Indian Ocean from winter to summer, we find that the temperature anomalies that center around Sumatra in late spring and early summer can be traced back to the variations of the SST fields in the South China Sea in the preceding winter. Being well associated with the outbreak of the South China Sea monsoon, the latter is a significant index for it. The work helps understanding the atmospheric and oceanic background against which the South China Sea monsoon breaks out and behaves.

  5. Post-breakup Basin Evolution along the South-Atlantic Margins in Brazil and Angola/Namibia

    Science.gov (United States)

    Kukla, P. A.; Strozyk, F.; Back, S.

    2013-12-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  6. Efects of Crop Growth on Hydrological Processes in River Basins and on Regional Climate in China

    Institute of Scientific and Technical Information of China (English)

    QIN; Pei-Hua; CHEN; Feng; XIE; Zheng-Hui

    2013-01-01

    The regional climate model RegCM3 incorporating the crop model CERES,called the RegCM3CERES model,was used to study the efects of crop growth and development on regional climate and hydrological processes over seven river basins in China.A 20-year numerical simulation showed that incorporating the crop growth and development processes improved the simulation of precipitation over the Haihe River Basin,Songhuajiang River Basin and Pearl River Basin.When compared with the RegCM3 control run,RegCM3CERES reduced the negative biases of monthly mean temperature over most of the seven basins in summer,especially the Haihe River Basin and Huaihe River Basin.The simulated maximum monthly evapotranspiration for summer(JJA)was around 100 mm in the basins of the Yangtze,Haihe,Huaihe and Pearl Rivers.The seasonal and annual variations of water balance components(runof,evapotranspiration and total precipitation)over all seven basins indicate that changes of evapotranspiration agree well with total precipitation.Compared to the RegCM3,RegCM3CERES simulations indicate reduced local water recycling rate over most of the seven basins due to lower evapotranspiration and greater water flux into these basins and an increased precipitation in the Heihe River Basin and Yellow River Basin,but reduced precipitation in the other five basins.Furthermore,a lower summer leaf area index(1.20 m2m 2),greater root soil moisture(0.01 m3m 3),lower latent heat flux(1.34 W m 2),and greater sensible heat flux(2.04 W m 2)are simulated for the Yangtze River Basin.

  7. Mechanisms of Cenozoic deformation in the Bohai Basin, Northeast China: Physical modelling and discussions

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Jianxun; ZHOU; Jiansheng

    2006-01-01

    The Bohai Basin is a Cenozoic petroliferous extensional basin in China and has apparent geometrical and kinematic similarities with the other Meso-Cenozoic extensional basins located along the eastern margin of Eurasian Plate. However, the deformation mechanisms of the basin are still in dispute. Physcial modelling referring to the Huanghua Depression, located in the central part of the Bohai Basin was conducted employing four sets of planar sandbox experimental models with different extension directions. Only experimental results of the model with N-S extension show good structural similarity with the depression. The results also indicate that complex variations of fault strike in a rift basin are not necessarily the results of complex kinematic mechanisms or polyphase deformation. Based on comparison of experimental results with the actual structures and the good structural similarity between Huanghua Depression and the whole Bohai Basin, it is concluded that the Bohai Basin was formed by the N-S extension. The strike slip deformation along the NNE-trending border faults of the basin resulted from the N-S extension and played the role of lateral transformation for the N-S extension. In addition, according to the apparent geometrical and kinematic similarities among the Bohai Basin and other Meso-Cenozoic extensional basins located along the eastern margin of the Eurasian Plate, it is proposed that: (1) this "N-S extension" model provides a better kinematic interpretation for the formation of Bohai Basin and the other adjacent basins located along the eastern margin of the Eurasian Plate; and (2) the N-S extension was probably the effect of the "slab window" formed by the subduction of the nearly E-W trending oceanic ridge between the Kula and Pacific Plates. The "slab window" effect can also provide reasonable explanations for the phenomena that initial rifting ages of basins become progressively younger westwards along the eastern margin of the Eurasian Plate

  8. Magnetic minerals in three Asian rivers draining into the South China Sea: Pearl, Red, and Mekong Rivers

    Science.gov (United States)

    Kissel, Catherine; Liu, Zhifei; Li, Jinhua; Wandres, Camille

    2016-05-01

    The use of the marine sedimentary magnetic properties, as tracers for changes in precipitation rate and in oceanic water masses transport and exchanges, implies to identify and to characterize the different sources of the detrital fraction. This is of particular importance in closed and/or marginal seas such as the South China Sea. We report on the magnetic properties of sedimentary samples collected in three main Asian rivers draining into the South China Sea: the Pearl, Red, and Mekong Rivers. The geological formations as well as the present climatic conditions are different from one catchment to another. The entire set of performed magnetic analyses (low-field magnetic susceptibility, ARM acquisition and decay, IRM acquisition and decay, back-field acquisition, thermal demagnetization of three-axes IRM, hysteresis parameters, FORC diagrams, and low-temperature magnetic measurements) allow us to identify the magnetic mineralogy and the grain-size distribution when magnetite is dominant. Some degree of variability is observed in each basin, illustrating different parent rocks and degree of weathering. On average it appears that the Pearl River is rich in magnetite along the main stream while the Mekong River is rich in hematite. The Red River is a mixture of the two. Compared to clay mineral assemblages and major element contents previously determined on the same samples, these new findings indicate that the magnetic fraction brings complementary information of great interest for environmental reconstructions based on marine sediments from the South China Sea.

  9. Neogene coupling between Kuqa Basin and Southern Tien Shan Orogen, Northwestern China

    Institute of Scientific and Technical Information of China (English)

    何光玉; 陈汉林

    2004-01-01

    Based on the sedimentary and subsiding features of Kuqa foreland basin, this paper presents the following characteristics of Neogene coupling relationship between Kuqa Basin and Southern Tien Shan Orogen, Northwestern China:(l) The Southern Tien Shan Orogen underwent Neogene uplifting of 4 km in height and the Kuqa Basin underwent Neogene subsidence of 4-6 km in depth accordingly beginning in 25 Ma; (2) The Southern Tien Shan Orogen moved continuously toward the Kuqa Basin, with largest structural shortening rate of greater than 53.7%, and the north boundary of the Kuqa Basin retreated continuously southward accordingly since the Miocene; (3) There are two subsidence centers with high subsiding rates and large subsiding extent, located in the eastern and western Kuqa Basin respectively, with the subsiding maximizing in the deposition period of Kuqa Formation.

  10. Basin-Scale Sand Deposition in the Upper Triassic Xujiahe Formation of the Sichuan Basin, Southwest China: Sedimentary Framework and Conceptual Model

    Institute of Scientific and Technical Information of China (English)

    Xiucheng Tan; Qingsong Xia; Jingshan Chen; Ling Li; Hong Liu; Bing Luo; Jiwen Xia; Jiajing Yang

    2013-01-01

    The Upper Triassic Xujiahe(须家河) Formation in the Sichuan (四川) Basin,Southwes China is distinctive for the basin-scale sand deposition.This relatively rare sedimentary phenomenon has not been well interpreted.Here we addressed this issue by discussing sedimentary framework and conceptual model.Analysis of sedimentary setting implied that the basin received transgression during the deposition.It had multiple provenance supplies and river networks,as being surrounded by oldlands in multiple directions including the north,east and south.Thus,the basin was generally characterized by coastal and widely open and shallow lacustrine deposition during the Late Triassic Xujiahe period.This is similar to the modern well-known Poyang(鄱阳) Lake.Therefore,we investigated the framework and conceptual model of the Sichuan Basin during the Xujiahe period with an analogue to the Poyang Lake.Results show that the conceptual model of the deposition can be divided into transgressive and regressive stages.The first,third and fifth members of the formation are in transgressive stage and the deposits are dominated by shore and shallow lacustrine mud.In contrast,the deposition is mainly of braided river channel sand deposits during the regressive stage,mainly including the second,fourth and sixth members of the formation.The sand deposited in almost the entire basin because of the lateral migration and forward moving of the cross networks of the braided rivers.The multiple alternations of short and rapid transgression and relatively long regression are beneficial to the basin-scale sand deposition.Thus,the main channel of the braided river and its extensional areas are favorable for the development of hydrocarbon reservoir.This provides practical significance to the reservoir evaluation and exploration.In addition,the results also justify the relatively distinctive sedimentary phenomenon in the study area and may also have implications for understanding the large

  11. Geothermal Regime, Thermal History and Hydrocarbon Generation Types of Sedimentary Basins in the Continental Area of China

    Institute of Scientific and Technical Information of China (English)

    QiuNansheng; JamesPuckette; JinZhijun; WangJiyang

    2005-01-01

    The thermal regimes in sedimentary basins in the continental area of China are varied and reflect differences in geological settings. As a result of these variable thermal regimes, the history of hydrocarbon generation in each basin is also different. An east-west profile of the thermal threshold across the continental basins of China, like the Liaohe Basin, the North China Basin, the Ordos Basin, the Qaidam Basin and the Tarim Basin, was constructed using large numbers of heat flow measurements, temperature data and rock thermophysical parameters. Isotherms, surface heat flow, mantle heat flow and Moho temperature beneath the basins are shown in the profile, which illustrates changes in some thermal characteristics between basins in east China and those in west China. Thermal evolution histories in basins were reconstructed using Easy%Ro method, apatite fission track annealing and other paleothermometers. Typical hydrocarbon generation histories of the primary source rocks were modeled by referring to the thermal evolution data. Thermal stages controlled source rocks maturation and oil and gas generation, and influenced the type of hydrocarbon (oil and gas) production in the basins.

  12. MARINE BIOFOULING IN OFFSHORE AREAS SOUTH OF HAINAN ISLAND, NORTHERN SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This study on the characteristics of fouling communities in offshore areas south of Hainan Island, northern South China Sea, was conducted at four sites there. At each station, test panels on iron frames were hung on the mooring system at different depths. Data on biofouling were mainly obtained by examination of the fouled test panels. Organisms attached to buoys and anchors were scraped off and examined also. The results showed that the thickness and biomass of marine growth that increased the fluid loading on offshore installations depended to a large extent on hard foulers, i.e. mollusks and acorn barnacles. Algae, hydroids, stalked barnacles and bryozoans were important fouling species. The occurrence frequency and biomass of acorn barnacles decreased with increasing distance from the shore.

  13. Influence of the Convection over the South China Sea on the Summer Precipitation of Shandong Province

    Institute of Scientific and Technical Information of China (English)

    ZHANG Suping; LIU Qinyu; GONG Dianli; LIU Shijun

    2004-01-01

    The pentad average minimum outgoing Iongwave radiation (OLR) data over the northern South China Sea (SCS)are selected as indexes to analyze the intensity of the convection connected with the SCS monsoon onset. Statistic analysis demonstrates that the index can account for the intensity of the SCS monsoon about, at least, 75 %. A significant negative correlation (confident level over 90% ) between Shandong's summer rainfall and the index is found only in the period of 24-26 pentads and limited to the area above the deeper water basin of the SCS (10°-20°N, 110°-117.5°E). Thus the minimum OLR over the deeper water basin during 24-26 pentads can be used as a valuable predictor for the long-lead forecast of the precipitation. The 500 hPa geopotential height data in the Northern Hemisphere for the period from 1951 to 2000 are used in order to characterize the physical mechanisms involved. The composite anomalies of the 500 hPa level allow for the identification and detection of the teleconnection of the East Asia-North America (EAP) pattern that is responsible to some extent for the interannual variability of the precipitation of Shandong Province. Besides, the interannual differences of the intraseasonal variations (ISV) of OLR and their northward transmission probably make a contribution to the position of the subtropical high which is vital for the summer rainfall in the province.

  14. Stretching characteristics and its dynamic significance of the northern continental margin of South China Sea

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To investigate the thinning of the whole crust, and the contribution of the upper versus lower crust to the stretching since Cenozoic, we calculated the stretching factor of the northern margin of South China Sea with data such as whole crustal thickness, depth of Cenozoic sedimentary basement and the horizontal displacement of faults. An isometric line drawing on whole crustal stretching factor is then obtained. Along the seismic Line 1530 in Baiyun sag, we also calculated the stretching factors of the upper and lower crust. The results suggest that the whole crustal thickness decreases seaward while the whole crustal stretching factor increases from shelf to slope. The Moho upwells highest beneath where the crust is thinned most. The value of the whole crustal stretching factor ranges from 1.5 to 6. Two areas were thinned intensely: the center of Yinggehai Basin, and the Baiyun sag in the Pearl River Mouth Basin. The calculation of the upper and lower crustal stretching factors from DSP1530 in Baiyun sag shows that the original crust of Baiyun sag should be thinned before deformation. Its pre-Cenozoic evolution as well as tectonic position during Cenozoic might be responsible for that.

  15. Stratigraphic Correlation of Middle Triassic Sequences among Different Paleogeographic Sedimentary Facies in South China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Affected by the Indosinian movement, the sediments in the main part of South China, Yangtzeplatform, started to transform from marine to continental during the Middle Triassic. In the meantime, a noticeable paleogeographic and sedimentary facies differentiation occurred in the marginal regions of the platforms and produced completely different lithologic and paleontologicsequences in various paleogeographic gradients and sedimentary facies areas, which brought about the difficulties for the stratigraphic correlation based on the traditional stratigraphies. This paper proposes to use some characteristic environmental events as the markers of the stratigraphic corre lation across various paleogeographic sedimentary facies, considering that some distinctive regionalenvironmental events should have affected at the same time on the entire basin or the connectedsedimentary regions and produced some closely related sedimentary records in the stratigraphic sequences though the affected intensity and recorded pattern might be different among the regions.The change of violent relative sea level (generally water depth) and the alteration of tectonic activity summarized from the dynamic mechanism of sedimentation are the best markers of environmental events for stratigraphic correlation. Based on the analysis and recognition of some significantenvironmental events at the typical stratigraphic sequences from various paleogeographic sedimentary facies and combined with the consideration of the variations in expressed form and strength fthe events among different paleogeographic gradients and sedimentary facies, the stratigraphic sequences from different sedimentary facies can be easily correlated directly. Furthermore, the evolutionary history of the whole sedimentary basin can be clearly established.

  16. Surveying the South Pole-Aitken basin magnetic anomaly for remnant impactor metallic iron

    Science.gov (United States)

    Cahill, Joshua T.S.; Hagerty, Justin J.; Lawrence, David M.; Klima, Rachel L.; Blewett, David T.

    2014-01-01

    The Moon has areas of magnetized crust ("magnetic anomalies"), the origins of which are poorly constrained. A magnetic anomaly near the northern rim of South Pole-Aitken (SPA) basin was recently postulated to originate from remnant metallic iron emplaced by the SPA basin-forming impactor. Here, we remotely examine the regolith of this SPA magnetic anomaly with a combination of Clementine and Lunar Prospector derived iron maps for any evidence of enhanced metallic iron content. We find that these data sets do not definitively detect the hypothesized remnant metallic iron within the upper tens of centimeters of the lunar regolith.

  17. Post-socialist international migration: The case of China-to-South Korea ethnic labour migration

    OpenAIRE

    Kim, Anna Myunghee

    2010-01-01

    This paper examines an atypical south-north labour migration that emerged in the post-socialist international migration system: China-to-South Korea ethnic labour migration. Over the past decade, South Korea has experienced an unprecedented increase in the arrival of foreign labour. The majority of workers come from the People's Republic of China. Based on a contextual multivariate analysis of primary survey data on 525 predominantly undocumented Korean Chinese labour migrants in Seoul, this ...

  18. Future acidification of marginal seas: A comparative study of the Japan/East Sea and the South China Sea

    Science.gov (United States)

    Luo, Yiming; Boudreau, Bernard P.

    2016-06-01

    The response of marginal (peripheral) seas to ocean acidification on short and long time scales is not well established. Through modeling, we examine the future acidification of two adjacent marginal seas, the South China Sea (SCS) and the Japan/East Sea (J/ES). Our results illustrate the importance of unique features in determining their acidification. The J/ES basin will become completely undersaturated with regard to calcite rapidly in the next few decades, while the SCS basin will experience relatively slower acidification. During its acidification, the J/ES will continually act as a sink for atmospheric CO2, whereas the SCS will temporarily switch from a source to a sink during the peak pCO2 interval, only to return slowly to being a source again. Marginal sea acidification will be determined by multiple factors, including their connections with the open ocean and their unique physical and biogeochemical dynamics, in addition to the level of atmospheric CO2.

  19. The formation of post-spreading volcanic ridges in the South China Sea

    Science.gov (United States)

    Zhao, Minghui; Sibuet, Jean-Claude; He, Enyuan; Tan, Pingchuan; Wang, Jian; Qiu, Xuelin

    2016-04-01

    In the South China Sea (SCS), the post-spreading magmatism (˜8-13 Ma) largely masks the previous spreading fabric. The resulting post-spreading seamounts are more numerous in the northern part than in the southern part of the East sub-basin. In the eastern part of the East sub-basin, the post-spreading volcanic ridge (PSVR) is approximately N055° oriented and follows the extinct spreading ridge (ESR). In the western part of the East sub-basin, the PSVR, called the Zhenbei-Huangyan seamounts chain, is E-W oriented and hides the ESR. Based on swath bathymetric and magnetic data, the ESR in the eastern part of the East basin is also N055° oriented and thus is oblique the E-W Zhenbei-Huangyan seamounts chain (Sibuet et al., 2016). We conducted a seismic refraction survey covering both the Zhenbei-Huangyan seamounts chain and the adjacent ESR, providing new constraints for understanding the relationship between the PSVR and the ESR. The detailed velocity structure shows that the Zhenbei-Huangyan seamounts chain was emplaced through a typical oceanic crust. The thicknesses of Zhenbei (14 km) and Huangyan seamounts (8 km) are larger than the ones of the normal oceanic crust. The correlation between crustal thicknesses and mean lower-crustal seismic velocities suggest that an asymmetric generation of seamounts in the East sub-basin where active upwelling mantle (Holbrook et al., 2001), the presence of a fertile mantle component (Korenaga et al., 2002), or buoyancy-driven decompression melting may happened (Castillo et al., 2010). Below the seamounts, the thickened lower crust is probably due to secondary magmatic intrusions and the large thickness of upper crust is possibly due to volcanic extrusions. The crustal thicknesses as well as the mean lower-crustal velocities of the Zhenbei and Huangyan seamounts are different, suggesting an independent origin for magmatic feeding. This research was granted by the Natural Science Foundation of China (91028002, 91428204

  20. Aptian biostratigraphy in South Zagros Basin, southwest Iran

    Institute of Scientific and Technical Information of China (English)

    Massih Afghah; Arash Shaabanpour Haghighi

    2014-01-01

    The Khami group within the petroliferous Zagros Basin of Iran includes the Surmeh, Hith, Fahliyan, Gadvan and Dariyan formations. The Dariyan Formation, previously known as Orbitolina limestone is very signif-icant as a reservoir rock in the Zagros Basin. In this study, the age of the Dariyan Formation is examined based on biostratigraphic and paleontological investigations. 236 m of Dariyan Formation sediments in the sections at Kuh-e Rahmat (north) and Nour-Abad (west) of Iran were selected to study its biostratigraphy. According to the lithostratigraphic investigations, the Dariyan Formation in these sections is subdivided into three: lower, middle and upper, which include thin-bedded to medium-bedded and massive lime-stone. Micropaleontologic study of the Dariyan Formation has led to the recognition of two biozones in the Nour-Abad area and one biozone in the Kuh-e Rahmat stratigraphic column. Diagnostic foraminifera in these sections are as follows: Globigerinel oides algerianus Cushman and Ten Dam, Globigerinelloides fer-reolensis Moullade, Globigerinelloides maridalensis (Bolli), Globigerinelloides paragottisi Verga and Permoli Silva, Hedbergel a aptiana Bartenstein, Hedbergel a excelsa Longoria, Hedbergel a luterbacheri Longoria, Hedbergella occulta Longoria, Hedbergella ruka (Banner et al.), Hedbergella similis Longoria, Hedbergella trocoidea (Gandolfi), Muricohedbergella delrioensis (Carsey), Pseudoplanomalina cheniourensis Sigal, Con-icorbitolina conica d’Archiac, Iraqia sp., Mesorbitolina parva Douglass, Mesorbitolina pervia Douglass, Meso-rbitolina ovalis Gorog and Arnaud-Vanneau, Mesorbitolina subconcava Leymerie, Mesorbitolina texana (Roemer), Mesorbitolina ovalis-pervia Cherchi and Schroeder, Debarina hahounerensis Fourcade et al., Marssonel a trochus (d’Orbigny), Nezzazata sp., Orbitolina sp., Textularia sp.

  1. Detrital zircon provenance of Silurian-Devonian and Triassic sedimentary rocks of the western Yangtze Block: Constraint for the location of South China in Gondwana supercontinent

    Science.gov (United States)

    Chen, Qiong; Sun, Min; Zhao, Guochun

    2016-04-01

    During Paleozoic even to early Mesozoic, South China, along with a series of Asia continental blocks, dispersed from the northern margin of Gondwana, drifting across the Tethys Ocean and accreting to the final assembly of Asia in Triassic, which also accepted sediments sourced from the adjoining segments of east Gondwana and itself successively. However, the exact location of South China within the east Gondwana and other Asia blocks is arguing and confusing. Detrital zircon U-Pb geochronology and Hf isotope data from Paleozoic sedimentary rocks and massive Triassic flysch sequences kept in the western margin of South China (Danba-Longmenshan regions) provide a record of the source from which they were derived, and thus being applied to constraining the distribution of basement block in paleogeographic reconstructions and the tectonic setting of the basin. Two Longmenshan Devonian sediments exhibit dominant Grenvillian ages (0.9-1.1 Ga), with mid-Neoproterozoic (730-850 Ma), Pan-African (500-680 Ma) and Neoarchean (2.4-2.5 Ga) age populations, indicative of a typical Gondwana-derived affinity, which is also recorded by the Danba Silurian sample and other Paleozoic sediments (Devonian-Cambrian) in the resting South China block, including the east Yangtze block and the Cathaysia. However, the similar age patterns are not observed in the Devonian sample of Danba region, which exhibits a different age pattern with only two significant age groups of Pan-African (440-600 Ma) and Neoproterozoic (660-994 Ma) with an apparent lack of older zircon grains (>1.0 Ga). The Triassic sandstone from Songpan-Ganze covering sequences shows a distinguished zircon age distribution with prominant mid-Neoproterozoic (649-843 Ma), mid-Paleoproterozoic (1724-1951 Ma) and subordinated Permian-Triassic (236-298 Ma), Paleozoic (375-530 Ma) ages, mainly derived by melting of old crust with few input of juvenile material. Considering provenance changes along with the temporal and variation in

  2. SEASONAL AND INTER-ANNUAL VARIABILITY OF THE SOUTH CHINA SEA WARM POOL AND ITS RELATION TO THE SOUTH CHINA SEA MONSOON ONSET

    Institute of Scientific and Technical Information of China (English)

    赵永平; 陈永利

    2001-01-01

    The South China Sea warm pool interacts vigorously with the summer monsoon which is active in the region. However, there has not been a definition concerning the former warm pool which is as specific as that for the latter. The seasonal and inter-annual variability of the South China Sea warm pool and its relations to the South China Sea monsoon onset were analyzed using Levitus and NCEP/NCAR OISST data. The results show that, the seasonal variability of the South China Sea warm pool is obvious, which is weak in winter, develops rapidly in spring, becomes strong and extensive in summer and early autumn, and quickly decays from mid-autumn. The South China Sea warm pool is 55 m in thickness in the strongest period and its axis is oriented from southwest to northeast with the main section locating along the western offshore steep slope of northern Kalimantan-Palawan Island. For the warm pools in the South China Sea, west Pacific and Indian Ocean, the oscillation, which is within the same large scale air-sea coupling system, is periodic around 5 years. There are additional oscillations of about 2.5 years and simultaneous inter-annual variations for the latter two warm pools. The intensity of the South China Sea warm pool varies by a lag of about 5 months as compared to the west Pacific one. The result also indicates that the inter-annual variation of the intensity index is closely related with the onset time of the South China Sea monsoon. When the former is persistently warmer (colder) in preceding winter and spring, the monsoon in the South China Sea usually sets in on a later (earlier) date in early summer. The relation is associated with the activity of the high pressure over the sea in early summer. An oceanic background is given for the prediction of the South China Sea summer monsoon, though the mechanism through which the warm pool and eventually the monsoon are affected remains unclear.

  3. Geology and hydrocarbon accumulations in the deepwater of the northwestern South China Sea-with focus on natural gas

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; SUN Zhipeng; ZHANG Daojun; ZHU Jitian; LI Xushen; HUANG Baojia; GUO Minggang; JIANG Rufeng

    2015-01-01

    The deepwater of the northwestern South China Sea is located in the central to southern parts of the Qiongdongnan Basin (QDN Basin), which is a key site for hydrocarbon exploration in recent years. In this study, the authors did a comprehensive analysis of gravity-magnetic data, extensive 3D seismic survey, cores and cuttings, paleontology and geochemical indexes, proposed the mechanism of natural gas origin, identified different oil and gas systems, and established the model of hydrocarbon accumulations in the deep-water region. Our basin tectonic simulation indicates that the evolution of QDN Basin was controlled by multiple-phased tectonic movements, such as Indochina-Eurasian Plate collision, Tibetan Uplift, Red River faulting and the expansion of the South China Sea which is characterized by Paleogene rifting, Neogene depression, and Eocene intensive faulting and lacustrine deposits. The drilling results show that this region is dominated by marine-terrestrial transitional and neritic-bathyal facies from the early Oligocene. The Yacheng Formation of the early Oligocene is rich in organic matter and a main gas-source rock. According to the geological-geochemical data from the latest drilling wells, Lingshui, Baodao, Changchang Sags have good hydrocarbon-generating potentials, where two plays from the Paleogene and Neogene reservoirs were developed. Those reservoirs occur in central canyon structural-lithologic trap zone, Changchang marginal trap zone and southern fault terrace of Baodao Sag. Among them, the central canyon trap zone has a great potential for exploration because the various reservoir-forming elements are well developed, i.e., good coal-measure source rocks, sufficient reservoirs from the Neogene turbidity sandstone and submarine fan, faults connecting source rock and reservoirs, effective vertical migration, late stage aggregation and favorable structural–lithological composite trapping. These study results provide an important scientific basis

  4. Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic: ocean-continent transformation (late Paleozoic to early mid-Triassic); intracontinental rift basin (late mid-Triassic to early Jurassic); down-warped basin (middle to late Jurassic); foreland basin (Cretaceous); and strike-slip basin (Cenozoic). Three major genetic types of Ag-Cu polymetailic ore deposits, including the reworked hydrothermal sedimentary, sedimentary-hydrothermally reworked and hydrothermal vein types, are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages. Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation, migration direction and emplacement processes of the basin fluids, thus causing differences in mineralization styles as well as in genetic types of ore deposit.

  5. Hydrocarbon potential of the Lamu basin of south-east Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Nyagah, K.; Cloeter, J.J.; Maende, A. [National Oil Corp. of Kenya, Nairobi (Kenya)

    1996-12-31

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  6. Hydrocarbon potential of the Lamu basin of south-east Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Nyagah, K.; Cloeter, J.J.; Maende, A. (National Oil Corp. of Kenya, Nairobi (Kenya))

    1996-01-01

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  7. Geomorphic Terrains and Evidence for Ancient Volcanism within Northeastern South Pole-Aitken Basin

    Science.gov (United States)

    Petro, Noah; Mest, Scott C.; Teich, Yaron

    2010-01-01

    The interior of the enigmatic South Pole-Aitken Basin has long been recognized as being compositionally distinct from its exterior. However, the source of the compositional anomaly has been subject to some debate. Is the source of the iron-enhancement due to lower-crustal/upper-mantle material being exposed at the surface, or was there some volume of ancient volcanism that covered portions of the basin interior? While several obvious mare basalt units are found within the basin and regions that appear to represent the original basin interior, there are several regions that appear to have an uncertain origin. Using a combination of Clementine and Lunar Orbiter images, several morphologic units are defined based on albedo, crater density, and surface roughness. An extensive unit of ancient mare basalt (cryptomare) is defined and, based on the number of superimposed craters, potentially represents the oldest volcanic materials within the basin. Thus, the overall iron-rich interior of the basin is not solely due to deeply derived crustal material, but is, in part due to the presence of ancient volcanic units.

  8. The influence of large-scale climate phenomena on precipitation in the Ordos Basin, China

    Science.gov (United States)

    Zhong, Yu; Lei, Liyuan; Liu, Youcun; Hao, Yonghong; Zou, Chris; Zhan, Hongbin

    2016-09-01

    Large-scale atmospheric circulations significantly affect regional precipitation patterns. However, it is not well known whether and how these phenomena affect regional precipitation distribution in northern China. This paper reported the individual and coupled effects of El Niño-Southern Oscillation (ENSO), Indian summer monsoon (ISM), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) on annual precipitation for the Ordos Basin, an arid and semi-arid basin, currently with major industries of coal, fossil oil, natural gas, and halite in north central China. Our results showed that ENSO and ISM exerted substantial impact on annual precipitation while the impact of PDO and AMO was relatively limited. There were 24 and 15 out of 33 stations showing significant differences (p Land) in the center of the basin were less affected by these large-scale climatic phenomena. An improved understanding of such relationships would be helpful in water resource planning and disaster management for the Ordos Basin.

  9. Basin and Crater Ejecta Contributions to the South Pole-Aitken Basin (SPA) Regolith; Positive Implications for Robotic Surface Samples

    Science.gov (United States)

    Petro, Noah E.; Jolliff, B. L.

    2011-01-01

    The ability of impacts of all sizes to laterally transport ejected material across the lunar surface is well-documented both in lunar samples [1-4] and in remote sensing data [5-7]. The need to quantify the amount of lateral transport has lead to several models to estimate the scale of this effect. Such models have been used to assess the origin of components at the Apollo sites [8-10] or to predict what might be sampled by robotic landers [11-13]. Here we continue to examine the regolith inside the South Pole-Aitken Basin (SPA) and specifically assess the contribution to the SPA regolith by smaller craters within the basin. Specifically we asses the effects of four larger craters within SPA, Bose, Bhabha, Stoney, and Bellinsgauzen all located within the mafic enhancement in the center of SPA (Figure 1). The region around these craters is of interest as it is a possible landing and sample return site for the proposed Moon-Rise mission [14-17]. Additionally, understanding the provenance of components in the SPA regolith is important for interpreting remotely sensed data of the basin interior [18-20].

  10. Deep Imaging of large scale extensional structures in the SW South China Sea

    Science.gov (United States)

    Liang, Yao; Delescluse, Matthias; Wang, Jun; Pubellier, Manuel; Chamot-Rooke, Nicolas; Qiu, Yan; Savva, Dimitri; Meresse, Florian

    2016-04-01

    The South China Sea (SCS) is the largest marginal basin in SE Asia and exhibits hundreds of kilometres of extended continental crust on both conjugate margins. The structures and processes leading to the formation of the SCS are still debated at various levels (timing, mechanisms). A joint collaboration between French and Chinese scientists led to the acquisition of coincident refraction and reflection seismic data over the SW sub-basin. In 2011, a 1000-km-long refraction line was first shot using R/V Tan Bao and 50 Ocean Bottom Seismometers (OBS). Among the results was the homogeneous thickness (~12 km) of the thinned continental crust over hundreds of kilometres and the possible large scale normal faults rooting in a ductile lower crust which could explain the relatively flat Moho. The coincident multichannel seismic (MCS) profile is now available to us. The 1000-km-long MCS line was acquired using a ~7000 cu.in. tuned airgun array and 6 to 8 km long streamers. Here we focus on a 230-km-long section of the profile to the south of the V-shaped SW oceanic basin across Spratley Islands. Multiples attenuation and high density velocity analysis are performed to obtain a detailed imaging of the sediments and crust at depth. We apply pre-stack Kirchhoff time migration and superimpose the obtained reflectivity on the refraction velocity model. The processed section includes a basin bound by a large crustal normal fault already imaged in the refraction velocity model, although no information on the basement was used to model the refraction velocities. The results validate the interpretation of the refraction velocity lateral variations and emphasize the significant vertical offsets of the large scale normal faults. Deep crustal reflectivity may give additional hints at a lower crustal ductile flow. Future work will consist in using the geometry of the MCS profiles in the refraction velocity modelling and an attempt to use more advanced migration methods with the help of

  11. Proposed new Lower Triassic stages in South China

    Institute of Scientific and Technical Information of China (English)

    TONG; Jinnan

    2001-01-01

    [1]Orchard, M., Executive notes from the Chair, Albertiana, 200l, 25: 3.[2]Yin Hongfu, Wu Shunbao, Du Yuansheng et al., South China defined as part of Tethyan sarchipelagic ocean system, Earth Science-Journal of China University of Geosciences (in Chinese with English abstract), 1999, 24(1): 1-12.[3]Tozer, E. T., The Trias and its ammonoids: the Evolution of a time scale, Geol. Surv. Canada, Miscellaneous Report, 1984,35: 1-171.[4]Gaetani, M., Report on the Meeting of the Subcommission, Albertiana, 1992, 10: 6-10.[5]Kozur, H., The problem of the Lower Triassic subdivision and some remarks to the position of the Permian-Triassic boundary, Jahrbuch fuer Geologie B. -A., 1993, 136(4): 795-797.[6]Chen Chuzhen, He Guoxiong, Chen Jinhua et al., Marine Triassic, Stratigraphical Studies in China (1979-1999) (in Chinese). Hefei: China University of Science and Technology Press, 2000, 241-259.[7]Zakharov. Y. D., Proposals on revision of the Siberian standard for the Lower Triassic and candidate stratotype section and point for the Induan-Olenekian boundary, A lbertiana, 1994, 14:44-51.[8]Yin Hongfu, Ding Meihua, Zhang Kexin et al., Dongwuan-Indosinian Ecostratigraphy of Yangtze Platform and its Margins (in Chinese with English summary), Beijing: Science Press, 1995, 1-338.[9]Tong Jinnan, Yang Yin, Advance in the Study of the Lower Triassic conodonts at Meishan Section, Changxing, Zhejiang Province. Chinese Science Bulletin, 1998, 43( 16): 1350-1353.[10]Tong Jinnan, Yin Hongfu, A study on the Griesbachian cyclostratigraphy of Meishan section, Changxing, Zhejiang Province. Journal of Stratigraphy (in Chinese with English abstract), 1999, 23(2): 130-135.[11]Sweet, W. C., Uppermost Permian and Lower Triassic conodonts of the Salt Range and Trans-Indus Ranges, West Pakistan. in Stratigraphic Boundary Problems: Permian and Triassic of West Pakistan (eds., Kummel, B., Teichert, C.), University of Kansas, Department of Geology Special

  12. Sources and summaries of water-quality information for the Rapid Creek basin, western South Dakota

    Science.gov (United States)

    Zogorski, John S.; Zogorski, E.M.; McKallip, T.E.

    1990-01-01

    This report provides a compilation of water quality information for the Rapid Creek basin in western South Dakota. Two types of information are included: First, past and current water quality monitoring data collected by the South Dakota Department of Water and Natural Resources, U.S. Forest Service, U.S. Geological Survey, and others are described. Second, a summary is included for all past water quality reports, publications, and theses that could be located during this study. A total of 62 documents were abstracted and included journal articles, abstracts, Federal agency reports and publications, university and State agency reports, local agency reports, and graduate theses. The report should be valuable to water resources managers, regulators, and others contemplating water quality research, monitoring, and regulatory programs in the Rapid Creek basin. (USGS)

  13. Typical synoptic situations and their impacts on the wintertime air pollution in the Guanzhong basin, China

    OpenAIRE

    Bei, Naifang; Li, Guohui; Huang, Ru-Jin; Cao, Junji; Meng, Ning; Feng, Tian; Liu, Suixin; Zhang, Ting; Zhang, Qiang; Molina, Luisa T.

    2016-01-01

    Rapid industrialization and urbanization have caused severe air pollution in the Guanzhong basin, northwestern China, with heavy haze events occurring frequently in recent winters. Using the NCEP reanalysis data, the large-scale synoptic situations influencing the Guanzhong basin during wintertime of 2013 are categorized into six types to evaluate the contribution of synoptic situations to the air pollution, including “north-low”, “southwest-trough”, “southeast-high”, “trans...

  14. Organic Carbon Isotope Geochemistry of the Neoproterozoic Doushantuo Formation, South China

    Institute of Scientific and Technical Information of China (English)

    GUO Qingjun; LIU Congqiang; Harald STRAUSS; Tatiana GOLDBERG; ZHU Maoyan; PI Daohui; WANG Jian

    2006-01-01

    The Neoproterozoic Doushantuo Formation on the Yangtze Platform, South China,documents a sedimentary succession with different sedimentary facies from carbonate platform to slope and to deep sea basin, and hosts one of the world-class phosphorite deposits. In these strata,exquisitely preserved fossils have been discovered: the Weng'an biota. This study presents carbon isotope geochemistry which is associated paired carbonate and organic matter from the Weng'an section of a carbonate platform (shelf of the Yangtze Platform, Guizhou Province) from the Songtao section and Nanming section of a transition belt (slope of the Yangtze Platform, Guizhou Province) and from the Yanwutan section (basin area of the Yangtze Platform, Hunan Province). Environmental variations and bio-events on the Yangtze Platform during the Late Neoproterozoic and their causal relationship are discussed. Negative carbon isotope values for carbonate and organic carbon (mean δ13Corg = -35.0%) from the uppermost Nantuo Formation are followed by an overall increase in δ13C up-section. Carbon isotope values vary between -9.9% and 3.6% for carbonate and between -35.6% and -21.5% for organic carbon, respectively. Heavier δ13Ccarb values suggest an increase in organic carbon burial, possibly related to increasing productivity (such as the Weng'an biota). The δ13C values of the sediments from the Doushantuo Formation decreased from the platform via the slope to basin,reflecting a reduced environment with minor dissolved inorganic carbon possibly due to a lower primary productivity. It is deduced that the classical upwelling process, the stratification structure and the hydrothermal eruption are principally important mechanisms to interpret the carbon isotopic compositions of the sediments from the Doushantuo Formation.

  15. A new evaporation duct climatology over the South China Sea

    Science.gov (United States)

    Shi, Yang; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2015-10-01

    The climatology of evaporation ducts is important for shipborne electromagnetic system design and application. The evaporation duct climatology that is currently used for such applications was developed in the mid 1980s; this study presents efforts to improve it over the South China Sea (SCS) by using a state-of-the-art evaporation duct model and an improved meteorology dataset. This new climatology provides better evaporation duct height (EDH) data over the SCS, at a higher resolution of 0.312°×0.313°. A comparison between the new climatology and the old one is performed. The monthly average EDH in the new climatology is between 10 and 12 m over the SCS, higher than that in the old climatology. The spatiotemporal characteristics of the evaporation duct over the SCS in different months are analyzed in detail, based on the new climatology.

  16. Geochemistry of Soil Formation in south China Sea Islands

    Institute of Scientific and Technical Information of China (English)

    GONGZI-TONG; HUANGBIAO

    1995-01-01

    The soils in South China sea Islands(SCSI)were divided into three types,nmaely,phospho-calc soils,skeletisols and coastic solonchake,which were derived from bio-clastic and strongly calcareous sediments.In comparison with their parent materials,the phospho-Calc soils have higher contents of P,Zn Cu,Ba,and Cd,which tend to increase gradually with time,and lower contents of Mg,Ca,Sr,B,V,Pb,and Mo,which tend to decrease by degrees with time,The above-mentioned constituents in skeletisols and coastic solonchaks are similar to those in their parent materials except for P and Na,The factors affecting element distribution are mainly special bioclimate and parent material,meanwhile,resulting in the remakable influence on element distribution through soil-forming time.

  17. Cambrian Fossil Embryos from Western Hunan,South China

    Institute of Scientific and Technical Information of China (English)

    DONG Xiping

    2009-01-01

    The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan,South China are described and illustrated in detail for the first time.A new species Markuelia elegans sp.nov.is established based mainly on embryos from the Upper Cambrian.A few of animal's resting eggs,which are comparable with those of the Ediacaran Doushantuo Formation,have been also found in the Upper Cambrian of western Hunan.The membrane of oue egg from the uppermost Cambrian has been replaced by pyrite and the overgrowth of the pyrite crystals exhibits a unique inorganic reducing conditions promoted the excellent preservation for the Markuelia specimens.The study of Markuelia provides not only constraint on the anatomy,affinity,embryonic development and phylogenetic significance of this wormlike animal and but also opens a new window onto the evolution and development of the earliest animals.

  18. Intake fraction of primary pollutants: motor vehicle emissions in the South Coast Air Basin

    OpenAIRE

    J. D. Marshall; W. J. Riley; McKone, T.E.; Nazaroff, William W.

    2003-01-01

    The intake fraction is defined for a specific species and emission source as the ratio of attributable population intake to total emissions. Focusing on California's South Coast Air Basin (SoCAB) as a case study, we combine ambient monitoring data with time-activity patterns to estimate the population intake of carbon monoxide and benzene emitted from motor vehicles during 1996-1999. In addition to exposures to ambient concentrations, three microenvironments are considered in which the exposu...

  19. Geothermal field and thermotectonic evolution in Southern South Yellow Sea Basin

    Institute of Scientific and Technical Information of China (English)

    YANG Shuchun; HU Shengbiao; CAI Dongsheng; FENG Xiaojie; GAO Le; LU Jingmei

    2003-01-01

    Based on the available borehole temperature data and measurements of thermal conductivities on 10 core samples in the Southern South Yellow Sea Basin, 8 heat flow values are obtained. The results show that the mean values of temperature gradient and heat flow are 28.6℃/km and 69 mW/m2, respectively. The thermal history reconstruction from the inversion of vitrinite reflectance data, using the temperature-gradient method, indicates that the highest paleo-heat flow occurred at the end of the Mesozoic, and then the basin began to cool to present day. Tectonic subsidence analysis shows that the basin experienced at least four episodes of quick subsidence since the late Paleozoic and that the tectonic evolution was quite strong and complex.

  20. Radionuclides in plankton from the South Pacific Basin

    International Nuclear Information System (INIS)

    We have initiated an investigation of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review has shown that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 104. We participated in Operations Deepfreeze 1981 and 1982, collecting a total of 48 plankton samples from the USCGC Glacier on its Antarctic cruises. Battelle Pacific Northwest Laboratories sampled air, water, rain, and fallout. We were able to measure concentrations in plankton of the naturally-occurring radionuclides 7Be, 40K, and the U and Th series, and we believe that we have detected low levels of 144Ce and 95Nb in seven samples ranging as far south as 680. Biological identification of the plankton suggests a possible correlation between radionuclide concentration and the protozoa content of the samples. 7 references, 5 figures

  1. Recent developments in study of the typical superimposed basins and petroleum accumulation in China:Exemplified by the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    JIN Zhijun; WANG Qingchen

    2004-01-01

    Most of petroliferous sedimentary basins in China have experienced multiple phases of tectonic evolution and deposition, and are characterized by tectonic and depositional superimposition. The term "superimposed basin" is suggested to describe those basins which consist of two or more simple prototype basins superimposing vertically and/or coalescing laterally. The characteristics of petroliferous superimposed basins are "multiple stages of basin forming and reworking, multiple layers of source rocks, multiple periods of hydrocarbon generation and expulsion, multiple periods of petroleum migration-accumulation-escape". Therefore,applying the wave process analysis method to studying the process of basin formation, hydrocarbon generation, and reservoir formation, and then establishing theory of "petroleum accumulation system" is helpful to enhancing petroleum exploration efficiency in superimposed basins.This paper will, based on case study in the Tarim basin, report the major developments in studying basin formation, hydrocarbon generation and petroleum accumulation. In study of basin formation, (1) geophysical comprehensive profiles reveal that the Tarim plate has been subducted beneath the Tianshan orogenic belt with an interfinger structure and that the deep structure in the eastern section of the Tianshan orogenic belt is different from that in the western section. (2) The vertical variation in debris and geochemical composition reveals the nature and Mesozoic-Cenozoic evolution history of the Kuqa Depression. (3) Field investigation and paleostress reconstruction show that the Kuqa Depression has undergone gravity-driven extension in sedimentary cover when the Tianshan uplifted vertically. In hydrocarbon generation study, new developments include (1) setting environmental index to judge high grade source rocks in marine carbonates, and (2) establishing the lower limit of the organic carbon content for effective carbonate source rocks. In petroleum accumulation

  2. Recent developments in study of the typical superimposed basins and petroleum accumulation in China: Exemplified by the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    JIN; Zhijun; WANG; Qingchen

    2004-01-01

    Most of petroliferous sedimentary basins in China have experienced multiple phases of tectonic evolution and deposition, and are characterized by tectonic and depositional superimposition. The term "superimposed basin" is suggested to describe those basins which consist of two or more simple prototype basins superimposing vertically and/or coalescing laterally. The characteristics of petroliferous superimposed basins are "multiple stages of basin forming and reworking, multiple layers of source rocks, multiple periods of hydrocarbon generation and expulsion, multiple periods of petroleum migration-accumulation-escape". Therefore,applying the wave process analysis method to studying the process of basin formation, hydrocarbon generation, and reservoir formation, and then establishing theory of "petroleum accumulation system" is helpful to enhancing petroleum exploration efficiency in superimposed basins.This paper will, based on case study in the Tarim basin, report the major developments in studying basin formation, hydrocarbon generation and petroleum accumulation. In study of basin formation, (1) geophysical comprehensive profiles reveal that the Tarim plate has been subducted beneath the Tianshan orogenic belt with an interfinger structure and that the deep structure in the eastern section of the Tianshan orogenic belt is different from that in the western section. (2) The vertical variation in debris and geochemical composition reveals the nature and Mesozoic-Cenozoic evolution history of the Kuqa Depression. (3) Field investigation and paleostress reconstruction show that the Kuqa Depression has undergone gravity-driven extension in sedimentary cover when the Tianshan uplifted vertically. In hydrocarbon generation study, new developments include (1) setting environmental index to judge high grade source rocks in marine carbonates, and (2) establishing the lower limit of the organic carbon content for effective carbonate source rocks. In petroleum accumulation

  3. The typical large-scale superposed folds in the central South China: Implications for Mesozoic intracontinental deformation of the South China Block

    Science.gov (United States)

    Shi, Wei; Dong, Shuwen; Zhang, Yueqiao; Huang, Shiqi

    2015-11-01

    The South China Block has experienced polyphase intensive intracontinental deformation in the Mesozoic time. Large-scale superposed folds in central South China document the Mesozoic tectonic events within the South China Block. Here, we present new structural data related to synfolding deformation, coupling with chronological data, to reconstruct the deformation sequence and tectonic regime during crustal shortening. These data indicate that the superposed folds, dominated by a two-stage tectonic compressive regime, experienced two phases of superposed buckle folding, leading to the orthogonal superposition of NE-SW-trending folds onto WNW-ESE-trending folds between the late Middle Jurassic and the earliest Early Cretaceous. Our structural analysis, together with geochronological data for this area, suggests that the South China Block predominately underwent two phases of intracontinental deformation during the Mesozoic. The early phase of tectonism (D1) is characterized by a late Middle Triassic to earliest Early Jurassic NE-SW compression, causing the occurrence of an orogeny-perpendicular shortening accompanying with evident magmatism. This tectonic event was most likely associated with progressive clockwise collision of the South China Block toward the north in the Indosinian event. Subsequent tectonic activity (D2) between the late Middle Jurassic and the earliest Early Cretaceous contributed to a phase of NW-SE contraction that overprinted the early NE-SW shortening in the interior of the South China Block, generating a large-scale NW-convex fold belt and the typical large-scale superposed folds within the central South China Block. The later tectonism was probably driven by the NW-directed subduction of the paleo-Pacific Plate beneath the eastern part of the Asian continent.

  4. Tectonic Characteristics and Evolution of Bohai Bay Basin, China

    Institute of Scientific and Technical Information of China (English)

    LIU Pengju; ZHANG Meisheng; SUN Xiaomeng; YANG Baojun

    2002-01-01

    Synthetical analyzing the deep geophysical data within Bohai bay basin the authors detect the deep crustal structure presenting high geothermal flux, thinned crust and arched Moho discontinuity, and the basin basement belongs to rigid continental crust. The development of the basin was controlled by two - dimensional faults in NNE and NWW directions. The tectonic units of the basin can be subdivided into three structural divisions: the east, middle and west division. The basin is considered as a continental rift. The tectonic background and regional right - lateral stress field during the late Cretaceous and Paleogene were a compound result of the Kula Plate W - directional subducting under Eurasia Continental Plate in 80 ~ 74Ma and the Philippine sea Plate W -directional subducting under the Eurasia Continental Plate since 60Ma, the long-rang effect of the India Continental Plate wedging into the Eurasia Continental Plate and of the Siberia Plate SE - directional relatively moving.

  5. Molecular genetic assay of mucopolysaccharidosis IVA in South China.

    Science.gov (United States)

    He, Dengmin; Huang, Yonglan; Ou, Zhiying; Sheng, Huiying; Li, Sheyong; Zhao, Xiaoyuan; Li, Ru; Zheng, Jipeng; Liu, Li

    2013-12-10

    Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Molecular mutational analysis was performed by PCR product sequencing for fourteen exons and exon-intron boundaries of GALNS gene in 21 patients from 19 unrelated families with severe MPS IVA in South China. We identified fifteen different mutations, including 10 reported mutations (p.P125L, p.G290S, p.M318R, p.G340D, p.L366P, p.R386C, p.A392V, c.1243-1G>C, p.L440RfsX54 and p.X523E) and five novel mutations (p.N177S, p.G290R, p.F306S, p.W403_T404delinsCS, p.W520X). All five novel mutations were inherited from parents of the patients and not found in 100 normal control alleles. Three mutations, p.M318R, p.L366P and p.R386C were common, accounting for 36.8% of mutant alleles investigated. One patient homozygous of p.A392V and the other two unrelated patients homozygous of p.L366P presented classical disease course. The results show that the GALNS gene has a different mutational spectrum in South China as compared to other regions. The p.A392V and p.L366P mutations were associated with severe phenotype of MPS IVA.

  6. Analysis of the geological structure and tectonic evolution of Xingning-Jinghai sag in deep water area, northern South China Sea

    Science.gov (United States)

    Han, Xiaoying; Ren, Jianye; Lin, Zi; Yang, Linlong

    2015-04-01

    Recent years, oil and gas exploration of the Pearl River Mouth Basin in the northern margin of South China Sea continuously achieved historic breakthroughs. The Xingning-Jinghai sag, which is located in southeast of the Pearl River Mouth Basin, is a deep-water sag with a great exploration potential. Its tectonic evolution is extremely complex. It experienced Mesozoic subduction to Cenozoic intra-continental rifting background, and finally evolved into a deep-water sag of the northern continental margin of South China Sea. The geological characteristics and the tectonic evolution of Xingning-Jinghai sag was closely related to the process of formation and evolution of the passive continental margin of the northern South China Sea. It is confirmed by many geophysical data that compared with adjacent Chaoshan depression, the crustal thickness of Xingning-Jinghai sag was rapidly thinning, and it developed detachment faults with later magmatic intrusion. The development of detachment faults have dynamic significance for the spreading of the South China Sea. Based on the seismic geological interpretation of 2D seismic data in the study area, the characteristics of detachment fault and supra-detachment basin have been proposed in this study. The characteristics of the detachment fault are low angle and high ratio between heave and throw. The geometry of the detachment fault is a typical lisric shape, with the dip of fault decreasing generally from the seismic profile. The detachment basin where sediments are not deposited over a tilting hanging-wall block but onto a tectonically exhumed footwall which is different from the typical half graben basin. Seismic profiles indicate two different structural styles in the east and west part of Xingning-Jinghai sag. In the west of the sag, there developed two large detachment faults, which control their detachment basin systems and the typical H block, and the two detachment faults are dipping landward and seaward, respectively. In

  7. South America Low-Level Jet and its effects on the precipitation over La Plata Basin

    Science.gov (United States)

    Llopart, Marta; Coppola, Erika; Giorgi, Filippo

    2015-04-01

    Studies with climate models have shown a dry bias in precipitation over La Plata Basin region for both regional and global models, which suggests a common deficiency in simulating the precipitation of the region. These deficiencies could be tied with the models parameterizations, which are not able to capture the dynamical systems as for example the low level jet, resulting in a weak latitudinal and meridional moisture transport. The goal of this work was to analyze the simulated South America low level jet and its impacts on the precipitation over La Plata Basin using different model parameterizations. In this work we used the Regional Climate Model (RegCM4) over CORDEX South America Domain. The model results were compared against Era-Interim analysis and CRU data. The results show that the low level jet representation is tied to both the precipitation convection scheme and the land-surface scheme. Several combinations of both convection and land-surface scheme have been tested and this can result in a weaker or stronger representation of the jet. The optimal configuration has been obtained and the physical explanation is presented. The jet position and strength is clearly influencing the precipitation spatial distribution and intensity over La Plata basin and by modeling the correct position and intensity the jet the dry bias over this basin is reduced.

  8. Impacts of Climate Change on Water and Agricultural Production in Ten Large River Basins in China

    Institute of Scientific and Technical Information of China (English)

    WANG Jin-xia; HUANG Ji-kun; YAN Ting-ting

    2013-01-01

    The overall goal of this paper is to examine impacts of climate change on water supply and demand balance and their consequences on agricultural production in ten river basins in China. To realize this goal, China Water Simulation Model (CWSM) is used to analyze three alternative climate scenarios (A1B, A2 and B2). The results show that the impacts of climate change on water supply and demand balance differ largely among alternative scenarios. While significant impacts of climate change on water balance will occur under the A1B scenario, the impacts of climate change under the A2 and B2 scenarios will be marginal. Under the A1B scenario, the water shortage in the river basins located in the northern China will become more serious, particularly in Liaohe and Haihe river basins, but the other river basins in the southern China will improve their water balance situations. Despite larger impacts of climate change on water balance in the northern China, its impacts on total crops’ production will be moderate if farmers would be able to reallocate water among crops and adjust irrigated and rainfed land. The paper concludes with some policy implications.

  9. Ra-226 and Pb-210/Ra-226 Activity Ratio in the Northern South China Sea

    Science.gov (United States)

    Chi-Ju, L.; Yu-Chia, C.; Tsung-En, W.

    2004-05-01

    The surface water distributions and vertical profiles of Ra-226 in the northern South China Sea (SCS) have been measured. Surface water Ra-226 varies between 10 and 16 dpm/100 kg with higher values at stations adjacent to the landmass. Each Ra-226 profile shows an increase from the surface toward the bottom. Above 1000m depth Ra-226 is systematically about 5 dpm/100kg higher in the northern South China Sea than in the western North Pacific. This difference may be attributed to a strong Ra-226 source from the shelf and slope area of the SCS. Below this depth Ra-226 displays large variation within some of the profiles with lower limits being comparable to the activities of the western North Pacific but higher limits being systematically about 5 dpm/100kg higher. These high Ra-226 activities may reflect effects of the longer isolation time for the deep water in the SCS basin and strong Ra input from the underlying sediments. The Pb-210/Ra-226 activity ratio ranges between 1.4 and 2.7 in the surface water with higher activity ratio at the station closer to the Luzon Strait. The Pb-210 in excess over Ra-226 in the surface water due to atmospheric input may penetrate to a depth of about 200 to 500m. Below this depth, Pb-210/Ra-226 activity ratio ranges between 0.5 and 0.7 because Pb-210 is scavenged by settling particulates. Box model calculations within a mixed layer of 50m in the area yield a mean residence time of about 1 yr for Pb-210 if an atmospheric Pb-210 flux of 1 dpm/cm2/y is adopted. The activity ratio of about 0.5 to 0.7 in the deep water corresponds to a Pb-210 mean residence time of about 30 to 70 yrs with respect to particulate scavenging.

  10. The effect of China's globalisation on the South African coal mining equipment (OEM) industry / Ramona Naidoo

    OpenAIRE

    Naidoo, Ramona

    2007-01-01

    The study looks at the mining equipment industry as coal mining equipment is a subsector within this industry. This study seeks to create an understanding of how the coal mining equipment industry in South Africa is affected by the emergence of China as a mining equipment supplier. China's globalisation is set to continue and will impact all industries. China's African Policy will also impact the African continent, as China will continue to invest and use Africa's mineral resources. Sourcing ...

  11. First high-resolution near-seafloor survey of magnetic anomalies of the South China Sea

    Science.gov (United States)

    Lin, J.; Xu, X.; Li, C.; Sun, Z.; Zhu, J.; Zhou, Z.; Qiu, N.

    2013-12-01

    We successfully conducted the first high-resolution near-seafloor magnetic survey of the Central, Southwest, and Northern Central Basins of the South China Sea (SCS) during two cruises on board Chinese R/V HaiYangLiuHao in October-November 2012 and March-April 2013, respectively. Measurements of magnetic field were made along four long survey lines, including (1) a NW-SE across-isochron profile transecting the Southwest Basin and covering all ages of the oceanic crust (Line CD); (2) a N-S across-isochron profile transecting the Central Basin (Line AB); and (3) two sub-parallel NE-SW across-isochron profiles transecting the Northern Central Basin of the SCS (Lines D and E). A three-axis magnetometer was mounted on a deep-tow vehicle, flying within 0.6 km above the seafloor. The position of the tow vehicle was provided by an ultra-short baseline navigation system along Lines D and E, while was estimated using shipboard GPS along Lines AB and CD. To investigate crustal magnetization, we first removed the International Geomagnetic Reference Field (IGRF) of 2010 from the measured magnetic data, and then downward continued the resultant magnetic field data to a horizontal plane at a water depth of 4.5 km to correct for variation due to the fishing depth of the deep-tow vehicle. Finally, we calculated magnetic anomalies at various water depths after reduction-to-the-pole corrections. We also constructed polarity reversal block (PRB) models of crustal magnetization by matching peaks and troughs of the observed magnetic field anomaly. Our analysis yielded the following results: (1) The near-bottom magnetic anomaly showed peak-to-trough amplitudes of more than 2,500 nT, which are several times of the anomaly amplitudes at the sea surface, illustrating that deep-tow measurements acquired much higher spatial resolutions. (2) The deep-tow data revealed several distinctive magnetic anomalies with wavelengths of 5-15 km and amplitudes of several hundred nT. These short

  12. Karst Aquifer Recharge: A Case History of over Simplification from the Uley South Basin, South Australia

    OpenAIRE

    Nara Somaratne

    2015-01-01

    The article “Karst aquifer recharge: Comments on ‘Characteristics of Point Recharge in Karst Aquifers’, by Adrian D. Werner, 2014, Water 6, doi:10.3390/w6123727” provides misrepresentation in some parts of Somaratne [1]. The description of Uley South Quaternary Limestone (QL) as unconsolidated or poorly consolidated aeolianite sediments with the presence of well-mixed groundwater in Uley South [2] appears unsubstantiated. Examination of 98 lithological descriptions with corresponding drillers...

  13. Limit analysis of extended reach drilling in South China Sea

    Institute of Scientific and Technical Information of China (English)

    Gao Deli; Tan Chengjin; Tang Haixiong

    2009-01-01

    Extended reach wells (ERWs), especially horizontal extended reach well with a high HD (horizontal displacement) to TVD (true vertical depth) ratio, represent a frontier technology and challenge the drilling limitations.Oil and gas reservoir in beaches or lakes and offshore can be effectively exploited by using extended reach drilling (ERD) technology.This paper focuses on the difficult technological problems encountered during exploiting the Liuhua 11-1 oil field in the South China Sea, China.Emphasis is on investigating the key subjects including prediction and control of open hole limit extension in offshore ERD, prediction of casing wear and its prevention and torque reduction, φ244.5mm casing running with floating collars to control drag force, and steerable drilling modes.The basic concept of limit extension in ERD is presented and the prediction method for open hole limit extension is given in this paper.A set of advanced drilling mechanics and control technology has been established and its practical results are verified by field cases.All those efforts may be significant for further investigating and practicing ERD limit theory and control technology in the future.

  14. South China Sea Territorial Disputes and Sino-Philippine Trade

    Institute of Scientific and Technical Information of China (English)

    FANG; WANG

    2015-01-01

    As political factors affect trade activities greatly, this paper considers whether a series of political events have had a negative impact on Sino-Philippine trade relations. Of particular concern is the influence on bilateral relations and the Philippines’ domestic economy from political and diplomatic tensions between China and the Philippines caused by territorial disputes in the South China Sea. Political events are divided into two levels, general conflicts and serious conflicts, which are analyzed from the perspectives of both overall level and product level to present their final impact on trade. This research finds that territorial disputes between the two countries deteriorated trade, as the volume of trade usually decreased distinctly after conflicts. The negative impact on trade generated by serious conflicts usually occurred more rapidly and on a larger scale. The effect of trade deterioration caused by political events weakened over time. Furthermore, after serious conflicts, although the volume of trade of certain products decreased temporarily, it rebounded quickly or even increased soon. However, industrial equipment or industrial raw materials trade activities between the two countries were basically independent of the conflicts’ impact.

  15. Genesis of Marine Carbonate Natural Gas in the Northeastern Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qu; TENGER; MENG Qingqiang; QIN Jianzhong; JIANG Qigui; ZHENG Lunju

    2008-01-01

    Sichuan Basin is one of the structurally stable and gas-rich basins, being regarded as one of China's important natural gas industry bases. Puguang and Jiannan gas fields, located in the eastern Sichuan Basin are two large fields with gas derived from Permian and Lower Triassic marine carbonate. The genesis of marine carbonate natural gas was examined using carbon isotope composition and hydrocarbon components of natural gas samples from the eastern and western Sichuan Basin, and compared with that of acidolysis gas derived from marine source rock in the eastern Sichuan Basin. It is concluded that the natural gas in the marine carbonate reservoir originated from pyrolysis of the earlier crude oil and light-oil, and then mixed with kerogen pyrolysis gas of the Permian and Lower Silurian source rock.

  16. The Survey of Ermia mangshanensis Resource in South China Tiger Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    Heping; XIE; Shizhou; LI; Jianrong; WANG; Yuanhui; CHEN; Lianchao; CHEN; Shengqiao; LEI

    2014-01-01

    In 2007,one living Ermia mangshanensis was found in the Shapingpian area at the junction of South China Tiger Nature Reserve in North Guangdong and Hunan Mangshan National Nature Reserve.To learn more about Ermia mangshanensis resource,the researchers in South China Tiger Nature Reserve in North Guangdong and Hunan Mangshan National Nature Reserve conducted field survey of Ermia mangshanensis in the Shapingpian area during the period 2010- 2012.The results show that there is Ermia mangshanensis in the Shapingpian area of South China Tiger Nature Reserve at the elevation of 800- 1200 m,and the population number is estimated at 48- 80.

  17. Sustainable development of agriculture in karst areas, South China

    Directory of Open Access Journals (Sweden)

    Linhua Song

    1999-01-01

    Full Text Available The exposed carbonate rocks aged from Sinian to Mid-Triassic Periods cover an area of 500,000 Km2 in south-west China. In karst areas with spectacular landscapes characterized by magnificent tower karst and conical karst, rare surface drainage systems and prevalent subsurface drainage systems, the environment is ecologically very fragile. The rapid increase of population, over deforested and cultivated lands, worsted the ecological system, causing a higher frequency of draught, flood and various disasters, backward economic development, low living standard of the people. In order to improve the sustainability of the agriculture the experience shows that the following operations should be adopted: (1 serious control of the population increase, emigration, extra labours and improvement of the environmental education of the local inhabitants; (2 terracing of the slopes (shi jala di as to improve the cultivated land quality, to preserve the water, soil and fertiliser and ameliorate the effective utilisation of the land; (3 development of new rural energies such as the solar energy and gas energy, and expansion of the saving-fuel stoves to reduce the load of bio-energy; (4 reforestation and bounding the hills and mountains; the ecological, economic and fuel forests model has been developed in fengcong-depression areas: the tree species with high ecological, economical and energetic characteristics, should be chosen, such as the bamboo, wild grapes, Sapium rotundifolium etc.; (5 better utilisation of the ram water and karst water resource to solve the water supply problems. The karst landscape is well developed in the 500,000 km2 carbonate terrain in Yunnan, Guizhou, Guangxi, west Hunan and south Sichuan provinces in south-west China, where 100 million habitants live (Song, 1997. The large population and its high density, serious deforestation, over-cultivation and fragile ecological system make the environmental problems very serious and about 30

  18. The development characteristics of source rocks in the main deepwater petroliferous basins of the world and their enlightenment to the study of source rocks in deep-water area of northern South China Sea%世界深水含油气盆地烃源岩的发育特征及对中国南海北部深水区烃源岩的启示

    Institute of Scientific and Technical Information of China (English)

    李文浩; 张枝焕; 李友川; 张功成; 傅宁

    2014-01-01

    rocks of transitional facies and paralic facies. With the supply of large quantities of organic matter of marine-continental transitional facies, paralic facies and prodelta facies at the late intraplate depression and under the margin-plate drifting condition, or in the circumstance of being long close to provenance, hydrocarbon source rocks would develop well. Source rocks do not develop at the late stage of rifting and the early stage of depressing. As a matter of fact, effective source rocks may develop under the condition of the supply of large quantities of organic matter from the semi-closed shallow sea and bathyal environment. The above characteristics have important guiding significance for the development of source rocks in northern South China Sea, where the main source rocks are lacustrine source rocks at the early rifting stage and marine-continental transitional facies source rocks at the late stage of rifting. Miocene marine source rocks vary in different basins. With enough terrestrial organic matter supply, source rocks from the Peal River Mouth basin is more effective than those from the Qiongdongnan basin. The exploration of Gulf of Mexico basin and northern Sumatra basin has proved that source rocks of bathyal facies seem to be effective source rocks, and this finding is of reference significance for the study of Miocene marine source rocks in northern South China Sea.

  19. Volume of Impact Melt Generated by the Formation of the South Pole-Aitken Basin

    Science.gov (United States)

    Petro, Noah E.

    2011-01-01

    The South Pole-Aitken Basin (SPA) is the largest, deepest, and oldest identified basin on the Moon and as such contains surfaces that are unique due to their age, composition, and depth of origin in the lunar crust [1-5] (Figure 1). SPA has been a target of intense interest as an area for robotic sample return in order to determine the age of the basin and the composition and origin of its interior [6-8]. In response to this interest there have been several efforts to estimate the likely provenance of regolith material within central SPA [9-12]. These model estimates suggest that, despite the formation of basins and craters following SPA, the regolith within SPA is dominated by locally derived material. An assumption of these models has been that the locally derived material is primarily SPA impact-melt as opposed to local basement material (e.g. unmelted lower crust). However, the definitive identification of SPA derived impact melt on the basin floor, either by remote sensing [5, 13] or via photogeology [2, 14] is extremely difficult due to the number of subsequent impacts and volcanic activity [4].

  20. Mineral provinces and material provenance of the surficial sediments near the Zhongsha Islands in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa; WANG Kunshan

    2007-01-01

    Characteristics and distribution patterns of clastic minerals (0.063~0.125 mm) in bottom sediments represent a significant indicator for the identification of the origin of sediment. One hundred and fourteen surface sediment samples, which were collected from the area near the Zhongsha Islands in the South China Sea, were analysed to identify the mineral suites and their distributions in the study area. The area can be divided into three mineral provinces: (Ⅰ) a province of biogenic minerals, which mainly originate from the Zhongsha Atoll; (Ⅱ) a province of volcanogenic minerals, which are mainly derived from local basaltic seamounts and small-scale volcanoes that are probably erupting, with some influences from the island-arc volcanic region around the South China Sea; and (Ⅲ) a mixed mineral province whose material source includes biogenic minerals, volcanogenic minerals and terrigenous minerals; the last province can be subdivided into a mixed mineral sub-province of the northeastern part of the study area, in which terrigenous minerals are mainly derived from China's Mainland and do not exceed 17°N, and a mixed mineral sub-province of the southeastern part of the study area, in which terrigenous minerals are derived from Kalimantan and Indochina Peninsula and might be further transported into the deep sea basin through submarine canyons.

  1. Deep-water Fan Systems and Petroleum Resources on the Northern Slope of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    PANG Xiong; YANG Shaokun; ZHU Ming; LI Jinsong

    2004-01-01

    The shallow shelf delta/strand arenaceous-pelitic deposit region in the north of the Pearl River mouth basin,sitting on the northern continental shelf of the South China Sea, has already become an important oil production base in China. Recent researched has revealed that a great deal of deep-water fans of great petroleum potentiality exist on the Baiyun deep-water slope below the big palco Pearl River and its large delta. Based on a mass of exploration wells and 2-D seismic data of the shallow shelf region, a interpretation of sequence stratigraphy confirmed the existence of deep-water fans. The cyclic falling of sea level, abundant detrital matter from the paleo Pearl River and the persistent geothermal subsidence in the Baiyun sag are the three prerequisites for the formation and development of deep-water fans. There are many in common between the deep-water shelf depositional system of the northern South China Sea and the exploration hotspots region on the two banks of the Atlantic. For example, both are located on passive continent margins, and persistent secular thermal subsidence and large palco rivers have supplied abundant material sources and organic matter.More recently, the discovery of the big gas pool on the northern slope of the Baiyun sag confirms that the Lower Tertiary lacustrine facies in the Baiyun sag has a great potentiality of source rocks. The fans overlying the Lower Tertiary source rocks should become the main exploration areas for oil and gas resources.

  2. Seasonal variations in the barrier layer in the South China Sea: characteristics, mechanisms and impact of warming

    Science.gov (United States)

    Zeng, Lili; Wang, Dongxiao

    2016-06-01

    A new observational dataset, the South China Sea Physical Oceanographic Dataset 2014, is examined to investigate the seasonal characteristics, formation mechanisms, and warming effects of the barrier layer (BL) in the South China Sea (SCS). Statistical analysis reveals that the BL is thicker and occurs more frequently during summer and early autumn, while in winter it often coexists with temperature inversions. The formation mechanisms are discussed from the perspective of the controlling regime and the net turbulent energy required for BL evolution. In the initial stage (March-May), the BL is absent due to weak mixing, scarce rainfall and surface warming. In the formation and maintenance stage (June-September), the BL grows in summer and persists into the transition season. The BLs can be classified into three regimes: the flux regime (in the Luzon Strait), the combined regime (in the eastern basin) and the wind regime (southeast of Vietnam). In the attenuation stage (October-February), associated with the winter monsoon, the BL mainly occurs in the combined regime (along the path of western boundary current) and the flux regime (in the southeast corner). The characteristics and generation mechanisms of the temperature inversions near the south Chinese coast, east of Vietnam, and in the Gulf of Thailand are also discussed. Our analysis further demonstrates that the BL has a significant warming effect on upper ocean temperature and heat content in the SCS.

  3. A magnetostratigraphic time frame for Plio-Pleistocene transgressions in the South Caspian Basin, Azerbaijan

    Science.gov (United States)

    Van Baak, C. G. C.; Vasiliev, I.; Stoica, M.; Kuiper, K. F.; Forte, A. M.; Aliyeva, E.; Krijgsman, W.

    2013-04-01

    The isolation of the Caspian Sea took place in the latest Miocene coinciding with a significant lowering of sea level and the deposition of a massive lowstand deltaic system. This so-called Productive Series is the main reservoir unit of the South Caspian oil-province. The Productive Series is overlain by marine clays from the Akchagylian and Apsheronian regional stages. During the Plio-Pleistocene, the Caspian basin experienced several short periods of intermittent connectivity with other marine basins. This work aims to create integrated, high-resolution, bio-magnetostratigraphic dating of these regional transgressions in key sections of the South Caspian Basin in Azerbaijan. We sample two long sections, the Lokbatan section in the Palaeo-Volga delta and the Xocashen section in the Kura Basin. Palaeoenvironmental reconstructions are derived from characteristic ostracod species. Rock magnetic analyses combined with thermal demagnetisation data indicate that the magnetic signal is carried dominantly by the iron oxide magnetite in the Productive Series of Lokbatan section and in the Xocashen section. The marine Akchagylian and Apsheronian of Lokbatan are characterised by the iron sulphide greigite, which appears to be of (near-) primary origin. The most logical correlation of the magnetic polarity patterns to the Geomagnetic Polarity Time Scale dates the Akchagylian transgression at ~ 3.2 Ma, a major transgression during the Apsheronian at ~ 2.0 Ma and the Bakunian transgression at 0.85-0.89 Ma. Ostracod assemblages indicate increasing salinities during these transgressions, from fresh water lacustrine to brackish-marine species. This implies that marine connections have been created with an adjacent basin that has a higher salinity, most likely the Black Sea.

  4. Managing water resources for sustainable development: the case of integrated river basin management in China.

    Science.gov (United States)

    Song, X; Ravesteijn, W; Frostell, B; Wennersten, R

    2010-01-01

    The emerging water crisis in China shows that the current institutional frameworks and policies with regard to water resources management are incapable of achieving an effective and satisfactory situation that includes Integrated River Basin Management (IRBM). This paper analyses this framework and related policies, examines their deficiencies in relation to all water stress problems and explores alternatives focusing on river basins. Water resources management reforms in modern China are reviewed and the main problems involved in transforming the current river management system into an IRBM-based system are analysed. The Huai River basin is used as an example of current river basin management, with quantitative data serving to show the scale and scope of the problems in the country as a whole. The institutional reforms required are discussed and a conceptual institutional framework is proposed to facilitate the implementation of IRBM in China. In particular, the roles, power and responsibilities of River Basin Commissions (RBCs) should be legally strengthened; the functions of supervising, decision-making and execution should be separated; and cross-sectoral legislation, institutional coordination and public participation at all levels should be promoted.

  5. Assessment of undiscovered continuous gas resources of the Ordos Basin Province, China, 2015

    Science.gov (United States)

    Charpentier, Ronald R.; Klett, Timothy R.; Schenk, Christopher J.; Brownfield, Michael E.; Gaswirth, Stephanie B.; Le, Phuong A.; Leathers-Miller, Heidi M.; Marra, Kristen R.; Mercier, Tracey J.

    2016-01-11

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean resources of 28 trillion cubic feet of tight gas and 5.6 trillion cubic feet of coalbed gas in upper Paleozoic rocks in the Ordos Basin Province, China.

  6. Thermal-rheological structure of the lithosphere beneath two types of basins in eastern and western China

    Institute of Scientific and Technical Information of China (English)

    王良书; 李成; 刘福田; 李华; 卢华复; 刘绍文

    2000-01-01

    After calculating thermal-rheological properties of the lithosphere in the Northern Jiangsu basin, the Bohaiwan basin as well as the Jiyang depression in the east and Tarim basin in the west of China, this paper analyzes the relationship between thermal-rheological structures and tectonic evolution of the two types of basins. The results show that the thermal-rheoiogical structures of the lithosphere directly reflect the dynamic processes. Under different dynamic environments, the style of basin formation and the differences in basin evolution are closely related to the dynamic properties of the lithosphere indicated by thermal-rheological structures.

  7. Detrital zircon provenance of the Late Triassic Songpan-Ganzi complex: Sedimentary record of collision of the North and South China blocks

    Science.gov (United States)

    Weislogel, A.L.; Graham, S.A.; Chang, E.Z.; Wooden, J.L.; Gehrels, G.E.; Yang, H.

    2006-01-01

    Using detrital zircon geochronology, turbidite deposystems fed from distinct sediment sources can be distinguished within the Songpan-Ganzi complex, a collapsed Middle to Late Triassic turbidite basin of central China. A southern Songpan-Ganzi deposystem initially was sourced solely by erosion of the Qinling-Dabie orogen during early Late Triassic time, then by Qinling-Dabie orogen, North China block, and South China block sources during middle to late Late Triassic time. A northern Songpan-Ganzi system was sourced by erosion of the Qinling-Dabie orogen and the North China block throughout its deposition. These separate deposystems were later tectonically amalgamated to form one complex and then uplifted as the eastern Tibet Plateau. ?? 2006 Geological Society of America.

  8. Geochemical discriminations of sandstones from the Mohe Foreland basin, northeastern China: Tectonic setting and provenance

    Institute of Scientific and Technical Information of China (English)

    HE Zhengjun; LI Jinyi; MO Shenguo; Andrey A. Sorokin

    2005-01-01

    Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the orogenic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional accumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.

  9. The influence of large-scale climate phenomena on precipitation in the Ordos Basin, China

    Science.gov (United States)

    Zhong, Yu; Lei, Liyuan; Liu, Youcun; Hao, Yonghong; Zou, Chris; Zhan, Hongbin

    2016-09-01

    Large-scale atmospheric circulations significantly affect regional precipitation patterns. However, it is not well known whether and how these phenomena affect regional precipitation distribution in northern China. This paper reported the individual and coupled effects of El Niño-Southern Oscillation (ENSO), Indian summer monsoon (ISM), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) on annual precipitation for the Ordos Basin, an arid and semi-arid basin, currently with major industries of coal, fossil oil, natural gas, and halite in north central China. Our results showed that ENSO and ISM exerted substantial impact on annual precipitation while the impact of PDO and AMO was relatively limited. There were 24 and 15 out of 33 stations showing significant differences (p planning and disaster management for the Ordos Basin.

  10. Improving water use efficiency under worsening scarcity: Evidence from the Middle Olifants sub-basin in South Africa

    OpenAIRE

    Walter, Teresa; Kloos, Julia; Tsegai, Daniel

    2010-01-01

    With the political changes in South Africa in the early 1990s, the South African government introduced a reform process in the entire water sector with the goal of a more enhanced and equitable water management system. This paper analyzes existing water allocation situations and applies a nonlinear optimization model to investigate the optimal intra- and inter-regional allocations in the Middle Olifants sub-basin of South Africa. Results show higher benefit from inter-regional water allocatio...

  11. Late Oligocene sedimentary environments and provenance abrupt change event in the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A significant change in composition was recorded in late Oligocene sediments from the northern South China Sea.This abrupt event coincided with the seafloor spreading axis jump across the Oligocene/Miocene boundary,leading to sedimentation breaks and slumps as well as obvious changes in sediment geochemical composition,and representing the greatest tectonic activity in the South China Sea region since the Oligocene.Through this tectonic event,the sedimentary environment in the Baiyun sag area transformed from a continental shelf in the late Oligocene to a continental slope since the early Miocene,the provenance of the sediments changed from neighboring areas to the hinterland of the South China block,and the sea level rose since the early Miocene in the area.Therefore,this abrupt change event has a profound influence on the evolution of petroleum offshore in the northern South China Sea.

  12. Improvement of the South China Sea Prediction System Using NSCAT Winds, A Research Project Outline

    OpenAIRE

    Peter C. Chu

    1999-01-01

    Peter C. Chu, Principal Investigator. Improvement of the South China Sea Prediction System Using NSCAT Winds, NASA/JPL (through California State University, Monterey Bay) NASA/JPL (through California State University

  13. DETERMINATION OF SOUTH CHINA SEA MONSOON ONSET AND EAST ASIAN SUMMER MONSOON INDEX

    Institute of Scientific and Technical Information of China (English)

    GAO-Hui; LIANG Jian-yin

    2006-01-01

    Results of the definition of South China Sea summer monsoon onset date and East Asian summer monsoon index in recent years are summarized in this paper. And more questions to be resolved are introduced later.

  14. Crustal structure across the Xisha Trough, northwestern South China Sea

    Science.gov (United States)

    Qiu, Xuelin; Ye, Sanyu; Wu, Shimin; Shi, Xiaobin; Zhou, Di; Xia, Kanyuan; Flueh, Ernst R.

    2001-11-01

    Located at the northwestern part of the South China Sea (SCS) between the Hainan and Xisha (Paracel) Islands, the Xisha Trough represents a failed rift in conjunction with the opening of the SCS between 32 and 17 Ma. From west towards east within a scale of several hundred kilometers, it presents all major stages of the rifting process, and thus, provides an ideal place to study the rifting process in great details. In the autumn of 1996, a joint team of Sino-German scientists carried out a wide-angle seismic experiment across the Xisha Trough with 10 ocean bottom hydrophones (OBH) along a 237-km NNW-SSE-oriented profile, which was surveyed in 1987 with multi-channel seismic (MCS) method by BGR of Germany and SOA of China. Favorable weather conditions and the powerful 4×12-l air gun array rendered very good quality data with seismic signals observed at the offset of up to 110 km. A detailed velocity-depth model was obtained by using an interactive trial-and-error 2D ray-tracing method. Interpretation of the MCS data published by BGR provides very good geometrical constraints of the complex upper crustal structure, which is characterized by fault blocks, half-horsts and half-grabens filled with syn- and post-rift Cenozoic sediments. The velocity model in turn confirms the major structure outlined by the interpretation of the MCS data, showing a varying sedimentary layer between 1 and 4 km of thickness and velocities between 1.7 and 4.5 km/s. The P-wave velocity of 5.5 km/s on the top of the crystalline basement is relatively low, suggesting strong weathering. Within the crystalline crust, the velocity increases downward continuously to 6.8 km/s at the bottom of the crust without a clear differentiation in the middle crust, showing clearly its continental nature even beneath the Xisha Trough. The Moho is marked by a sharp first-order interface with a velocity of 8.0-8.1 km/s at the uppermost mantle. The Moho depth is 15 km beneath the center of the trough and

  15. Oil and Gas Distribution in Hailar Basin,Northeast China

    Institute of Scientific and Technical Information of China (English)

    Yanbin Xu; Zishun Li; Ping Gao; Meng Tian; Xiuyun Qiao; Chuanbiao Wan

    2003-01-01

    Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Hailar Basin is a basin group consisted of many scattered sub-basins with similar structural developed history. Each sub-basin has unique hydrocarbon distributing rules, including (1) oil/gas reservoir distribution is controlled by the oil/gas sag, and the oil/gas bearing in big sag is rich; (2) underwater fan and turbidity fan are the most favorable reservoirs; structure zone controlled by main fault is favorable zone of forming composite oil/gas accumulation; (3) lower fault-block in higher rise and higher fault-block in lower rise are favorable to oil/gas accumulation; (4) deep fault and granite body are closely related to oil/gas reservoir, its distributing area is favorable area of oil and mantle source non-hydrocarbon gas formation;(5) higher geothermal area is favorable oil/gas bearing area.

  16. The growing relationship between South Korea and China consequences for North Korea

    OpenAIRE

    Renner, Laura

    2006-01-01

    After approximately forty years as enemies, South Korea and China normalized relations in 1992. This change has accelerated the growth of both of their already booming economies. Beyond that, it has helped propel Beijing into a pivotal role of influence since it now maintains friendly relations with both Koreas, currently the only country to do so. Nearly fifteen years after this normalization, South Korea and China still enjoy a strong relationship that generally continues to improve. Surpri...

  17. The assimilation experiment in the southwestern South China Sea in summer 2000

    Institute of Scientific and Technical Information of China (English)

    XIAO Xianjun; WANG Dongxiao; XU Jianjun

    2006-01-01

    We performed an assimilation experiment of the southern South China Sea in summer 2000, and the altimeter data were assimilated into Princeton Ocean Model (POM). The result was evaluated with the in situ data. There were obvious improvements of the currents in the southern South China Sea, and the modeling uncertainty coming from the error of wind stress forcing was reduced.This experiment provides us a new idea about improving the modeling of the ocean currents.

  18. Comparison among four kinds of data of sea surface wind stress in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    谢强; 王卫强; 毛庆文

    2002-01-01

    By using remote sensing (ERS) data, FSU data, GOADS data and Hellerman & Rcsenstein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies.

  19. Advances in Studying Oceanic Circulation from Hydrographic Data with Applications in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    王桂华; 李荣凤; 闫长香

    2003-01-01

    Methods for studying oceanic circulation from hydrographic data are reviewed in the context of their applications in the South China Sea. These methods can be classified into three types according to their different dynamics as follows: (1) descriptive methods, (2) diagnostic methods without surface and bottom forcing, and (3) diagnostic methods with the above boundary forcing. The paper discusses the progress made in the above methods together with the advancement of study in the South China Sea circulation.

  20. An observational analysis of a derecho in South China

    Science.gov (United States)

    Xia, Rudi; Wang, Donghai; Sun, Jianhua; Wang, Gaili; Xia, Guancong

    2012-12-01

    Derechos occur frequently in Europe and the United States, but reports of derechos in China are scarce. In this paper, radar, satellite, and surface observation data are used to analyze a derecho event in South China on 17 April 2011. A derecho-producing mesoscale convective system formed in an environment with medium convective available energy, strong vertical wind shear, and a dry layer in the middle troposphere, and progressed southward in tandem with a front and a surface wind convergence line. The windstorm can be divided into two stages according to differences in the characteristics of the radar echo and the causes of the gale. One stage was a supercell stage, in which the sinking rear inflow of a high-precipitation supercell with a bow-shaped radar echo induced a Fujita F0 class gale. The other stage was a non-supercell stage (the echo was sequentially kidney-shaped, foot-shaped, and an ordinary single cell), in which downbursts induced a gale in Fujita F1 class. This derecho event had many similarities with derechos observed in western countries. For example, the windstorm was perpendicular to the mean flow, the gale was located in the bulging portion of the bow echo, and the derecho moved southward along with the surface front. Some differences were observed as well. The synoptic-scale forcing was weak in the absence of an advancing high-amplitude midlevel trough and an accompanying strong surface cyclone; however, the vertical wind shear was very strong, a characteristic typical of derechos associated with strong synoptic-scale forcing. Extremely high values of convective available potential energy and downdraft convective available potential energy have previously been considered necessary to the formation of weak-forcing archetype and hybrid derechos; however, these values were much less than 2000 J during this derecho event.

  1. A review of stratigraphy and sedimentary environments of the Karoo Basin of South Africa

    Science.gov (United States)

    Smith, R. M. H.

    The Karoo Supergroup covers almost two thirds of the present land surface of southern Africa. Its strata record an almost continuous sequence of continental sedimentation that began in the Permo-Carboniferous (280 Ma) and terminated in the early Jurassic 100 million years later. The glacio-marine to terrestrial sequence accumulated in a variety of tectonically controlled depositories under progressively more arid climatic conditions. Numerous vertebrate fossils are preserved in these rocks, including fish, amphibians, primitive aquatic reptiles, primitive land reptiles, more advanced mammal-like reptiles, dinosaurs and even the earliest mammals. Palaeoenvironmental analysis of the major stratigraphic units of the Karoo sequence demonstrates the effects of more localised tectonic basins in influencing depositional style. These are superimposed on a basinwide trend of progressive aridification attributed to the gradual northward migration of southwestern Gondwanaland out of polar climes and accentuated by the meteoric drying effect of the surrounding land masses. Combined with progressive climatic drying was a gradual shrinking of the basin brought about by the northward migration of the subducting palaeo-Pacific margin to the south. Following deposition of the Cape Supergroup in the pre-Karoo basin there was a period of uplift and erosion. At the same time the southern part of Gondwana migrated over the South Pole resulting in a major ice-sheet over the early Karoo basin and surrounding highlands. Glacial sedimentation in both upland valley and shelf depositories resulted in the basal Karoo Dwyka Formation. After glaciation, an extensive shallow sea remained over the gently subsiding shelf fed by large volumes of meltwater. Black clays and muds accumulated under relatively cool climatic conditions (Lower Ecca) with perhaps a warmer "interglacial" during which the distinctive Mesosaurus-bearing, carbonaceous shales of the Whitehill Formation were deposited

  2. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

    Directory of Open Access Journals (Sweden)

    Z. Zeng

    2012-05-01

    Full Text Available Increasing water scarcity places considerable importance on the quantification of water footprint (WF at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB, a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr−1 in the HRB over 2004–2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production. The remaining 4% was for the industrial and domestic sectors. The "blue" component of WF was 811 million m3 yr−1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than green WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.

  3. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

    Directory of Open Access Journals (Sweden)

    Z. Zeng

    2012-08-01

    Full Text Available Increasing water scarcity places considerable importance on the quantification of water footprint (WF at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB, a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr−1 in the HRB over 2004–2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production. The remaining 4% was for the industrial and domestic sectors. The "blue" (surface- and groundwater component of WF was 811 million m3 yr−1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than "green" (soil water WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.

  4. Comparison of modern pollen distribution between northern and southern South China Sea

    Science.gov (United States)

    Luo, C.; Chen, M.; Xiang, R.; Liu, J.; Zhang, L.; Lu, J.

    2013-12-01

    To understand pollen transport mechanic and terrigenous area is the base to explain pollen data correctly in Southern South China Sea (Fig.1). Based on Palynology analyzing the following preliminary conclusions are listed. 1. Air pollen differences between northern and southern South China Sea 15 air pollen samples were collected from northern part of the South China Sea from August to September 2011. 13 air pollen samples were collected from southern South China Sea in December 2011. It was found that the air pollen are different between northern and southern part of South China Sea: the pollen types in the north are more abundant than in the south, Ulmaceae, Monolete spore, Cyperaceae, Euphorbiaceae, Rubiaceae, Artemisia, Chenopodiaceae, Rosaceae, Labiatae occur only in the north, they do not occur or is just sporadic in the south. The total pollen number and concentration in the north is 10 times of the south, one of the reasons may be that the sampling season in the north is autumn with more flowering plants, the sampling season in the south is winter, with fewer flowering plants; the second reason might be that pollen and spore in autumn and winter are mainly spread by the winter wind, thus they reduce from north to south. 2. Pollen differences of the surface sediments between northern and southern South China Sea 14 samples were collected from surface sediments in the northern part of the South China Sea from August to October, 2011. 12 samples were collected from surface sediments in the southern part of the South China Sea from year 1997 to 2002. The differences of pollen characteristics from the surface sediments between northern and southern part of South China Sea are: pollen types and quantities in the north are richer than in south. There are Trilete spores (35-100%), Pinus (3-65%) in northern of SCS, with pollen concentration of 33-1031grain/g. There are only a small amount of Trilete-spore and Pinus pollen in southern of SCS. Pollen concentration in

  5. On the tidally driven circulation in the South China Sea: modeling and analysis

    Science.gov (United States)

    Nelko, Varjola; Saha, Abhishek; Chua, Vivien P.

    2014-03-01

    The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. An unstructured-grid SUNTANS model is employed to perform depth-averaged simulations of the circulation in the South China Sea. The model is tidally forced at the open ocean boundaries using the eight main tidal constituents as derived from the OSU Tidal Prediction Software. The model simulations are performed for the year 2005 using a time step of 60 s. The model reproduces the spring-neap and diurnal and semidiurnal variability in the observed data. Skill assessment of the model is performed by comparing model-predicted surface elevations with observations. For stations located in the central region of the South China Sea, the root mean squared errors (RMSE) are less than 10 % and the Pearson's correlation coefficient ( r) is as high as 0.9. The simulations show that the quality of the model prediction is dependent on the horizontal grid resolution, coastline accuracy, and boundary locations. The maximum RMSE errors and minimum correlation coefficients occur at Kaohsiung (located in northern South China Sea off Taiwan coast) and Tioman (located in southern South China Sea off Malaysia coast). This may be explained with spectral analysis of sea level residuals and winds, which reveal dynamics at Kaohsiung and Tioman are strongly influenced by the seasonal monsoon winds. Our model demonstrates the importance of tidally driven circulation in the central region of the South China Sea.

  6. Preliminary description of hydrologic characteristics and contaminant transport potential of rocks in the Pasco Basin, south-central Washington

    International Nuclear Information System (INIS)

    This report aims at consolidating existing data useful in defining the hydrologic characteristics of the Pasco Basin within south-central Washington. It also aims at compiling the properties required to evaluate contaminant transport potential within individual subsurface strata in this basin. The Pasco Basin itself is a tract of semi-arid land covering about 2,000 square miles in south-central Washington. The regional geology of this basin is dominated by tholeiitic flood basalts of the Columbia Plateau. The surface hydrology of the basin is dominated by the Yakima, Snake, and Columbia rivers. Short-lived ephemeral streams may flow for a short period of time after a heavy rainfall or snowmelt. The subsurface hydrology of the Pasco Basin is characterized by an unconfined aquifer carrying the bulk of the water discharged within the basin. This aquifer overlies a series of confined aquifers carrying progressively smaller amounts of groundwater as a function of depth. The hydraulic properties of the various aquifers and non-water-bearing strata are characterized and reported. A summary of the basic properties is tabulated. The hydrochemical data obtained are summarized. The contaminant transport properties of the rocks in the Pasco Basin are analyzed with emphasis on the dispersion and sorption coefficients and the characteristics of the potential reactions between emplaced waste and the surrounding medium. Some basic modeling considerations of the hydrogeologic systems in the basin with a brief discussion of model input requirements and their relationship to available data are presented

  7. An integrated geophysical study on the Mesozoic strata distribution and hydrocarbon potential in the South China Sea

    Science.gov (United States)

    Hu, Weijian; Hao, Tianyao; Jiang, Weiwei; Xu, Ya; Zhao, Baimin; Jiang, Didi

    2015-11-01

    A series of drilling, dredge, and seismic investigations indicate that Mesozoic sediments exist in the South China Sea (SCS) which shows a bright prospect for oil and gas exploration. In order to study the distribution of Mesozoic strata and their residual thicknesses in the SCS, we carried out an integrated geophysical study based mainly on gravity data, gravity basement depth and distribution of residual Mesozoic thickness in the SCS were obtained using gravity inversion constrained with high-precision drilling and seismic data. In addition, the fine deep crustal structures and distribution characteristics of Mesozoic thicknesses of three typical profiles were obtained by gravity fitting inversion. Mesozoic strata in the SCS are mainly distributed in the south and north continental margins, and have been reformed by the later tectonic activities. They extend in NE-trending stripes are macro-controlled by the deep and large NE-trending faults, and cut by the NW-trending faults which were active in later times. The offset in NW direction of Mesozoic strata in Nansha area of the southern margin are more obvious as compared to the north margin. In the Pearl River Mouth Basin and Southwest Taiwan Basin of the north continental margin the Mesozoic sediments are continuously distributed with a relatively large thickness. In the Nansha area of the south margin the Mesozoic strata are discontinuous and their thicknesses vary considerably. According to the characteristics of Mesozoic thickness distribution and hydrocarbon potential analyses from drilling and other data, Dongsha Uplift-Chaoshan Depression, Southwest Taiwan Basin-Peikang Uplift and Liyue Bank have large thickness of the Mesozoic residual strata, have good hydrocarbon genesis capability and complete source-reservoir-cap combinations, show a bright prospect of Mesozoic oil/gas resources.

  8. Adaptive Fusion of Information for Seeing into Ordos Basin, China: A China-Germany-US Joint Venture.

    Science.gov (United States)

    Yeh, T. C. J.; Yin, L.; Sauter, M.; Hu, R.; Ptak, T.; Hou, G. C.

    2014-12-01

    Adaptive fusion of information for seeing into geological basins is the theme of this joint venture. The objective of this venture is to initiate possible collaborations between scientists from China, Germany, and US to develop innovative technologies, which can be utilized to characterize geological and hydrological structures and processes as well as other natural resources in regional scale geological basins of hundreds of thousands of kilometers (i.e., the Ordos Basin, China). This adaptive fusion of information aims to assimilate active (manmade) and passive (natural) hydrologic and geophysical tomography surveys to enhance our ability of seeing into hydrogeological basins at the resolutions of our interests. The active hydrogeophysical tomography refers to recently developed hydraulic tomgoraphic surveys by Chinese and German scientists, as well as well-established geophysical tomography surveys (such as electrical resistivity tomography, cross-borehole radars, electrical magnetic surveys). These active hydrogeophysical tomgoraphic surveys have been proven to be useful high-resolution surveys for geological media of tens and hundreds of meters wide and deep. For basin-scale (i.e., tens and hundreds of kilometers) problems, their applicabilities are however rather limited. The passive hydrogeophysical tomography refers to unexplored technologies that exploit natural stimuli as energy sources for tomographic surveys, which include direct lightning strikes, groundwater level fluctuations due to earthquakes, river stage fluctuations, precipitation storms, barometric pressure variations, and long term climate changes. These natural stimuli are spatially varying, recurrent, and powerful, influencing geological media over great distances and depths (e.g., tens and hundreds of kilometers). Monitoring hydrological and geophysical responses of geological media to these stimuli at different locations is tantamount to collecting data of naturally occurring tomographic

  9. The tectonic differences between the east and the west in the deep-water area of the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    XIA Zhongyu; WAN Zhifeng; WANG Xianqing; SHI Qiuhua; CAI Song; XIA Bin

    2016-01-01

    The deep-water area of the northern South China Sea, which has active and complicated tectonics, is rich in natural gas and gas hydrate. While the tectonic characteristics is different obviously between the east and the west because of the special tectonic position and tectonic evolution process. In terms of submarine geomorphology, the eastern shelf-slope structure in Pearl River Mouth Basin is characterized by having wide sub-basins and narrow intervening highs, whereas the western (Qiongdongnan Basin) structure is characterized by narrow sub-basins and wide uplift. As to the structural features, the deep-water sags in the east are all structurally half-grabens, controlled by a series of south-dipping normal faults. While the west sags are mainly characterised by graben structures with faulting in both the south and north. With regards to the tectonic evolution, the east began neotectonic activity when the post-rifting stage had completed at the end of the Middle Miocene. In the Baiyun Sag, tectonic activity became strong and was characterised by rapid subsidence and obvious faulting. Whereas in the west, neotectonic activity began at the end of the Late Miocene with rapid deposition and weak fault activity.

  10. Cenozoic magmatism in the northern continental margin of the South China Sea: evidence from seismic profiles

    Science.gov (United States)

    Zhang, Qiao; Wu, Shiguo; Dong, Dongdong

    2016-06-01

    Igneous rocks in the northern margin of the South China Sea (SCS) have been identified via high resolution multi-channel seismic data in addition to other geophysical and drilling well data. This study identified intrusive and extrusive structures including seamounts and buried volcanoes, and their seismic characteristics. Intrusive features consist of piercement and implicit-piercement type structures, indicating different energy input associated with diapir formation. Extrusive structures are divided into flat-topped and conical-topped seamounts. Three main criteria (the overlying strata, the contact relationship and sills) were used to distinguish between intrusive rocks and buried volcanos. Three criteria are also used to estimate the timing of igneous rock formation: the contact relationship, the overlying sedimentary thickness and seismic reflection characteristics. These criteria are applied to recognize and distinguish between three periods of Cenozoic magmatism in the northern margin of the SCS: before seafloor spreading (Paleocene and Eocene), during seafloor spreading (Early Oligocene-Mid Miocene) and after cessation of seafloor spreading (Mid Miocene-Recent). Among them, greater attention is given to the extensive magmatism since 5.5 Ma, which is present throughout nearly all of the study area, making it a significant event in the SCS. Almost all of the Cenozoic igneous rocks were located below the 1500 m bathymetric contour. In contrast with the wide distribution of igneous rocks in the volcanic rifted margin, igneous rocks in the syn-rift stage of the northern margin of the SCS are extremely sporadic, and they could only be found in the southern Pearl River Mouth basin and NW sub-sea basin. The ocean-continent transition of the northern SCS exhibits high-angle listric faults, concentrated on the seaward side of the magmatic zone, and a sharply decreased crust, with little influence from a mantle plume. These observations provide further evidence to

  11. Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content

    Science.gov (United States)

    Jin, Xiaobo; Liu, Chuanlian; Poulton, Alex J.; Dai, Minhan; Guo, Xianghui

    2016-08-01

    Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths) and the relative cellular levels of photosynthesis and calcification rates. All three of these factors vary between coccolithophore species and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition and cellular levels of calcite content. Average coccolithophore abundance and their calcite concentration in the water column were 11.82 cells mL-1 and 1508.3 pg C mL-1, respectively, during the cruise. Water samples can be divided into three floral groups according to their distinct coccolithophore communities. The vertical structure of the coccolithophore community in the water column was controlled by the trophic conditions, which were regulated by mesoscale eddies across the SCS basin. The evaluation of coccolithophore-based calcite in the surface ocean also showed that three key species in the SCS (Emiliania huxleyi, Gephyrocapsa oceanica, Florisphaera profunda) and other larger, numerically rare species made almost equal contributions to total coccolith-based calcite in the water column. For Emiliania huxleyi biometry measurements, coccolith size positively correlated with nutrients (nitrate, phosphate), and it is suggested that coccolith length is influenced by light and nutrients through the regulation of growth rates. Larger-sized coccoliths were also linked statistically to low pH and calcite saturation states; however, it is not a simple cause and effect relationship, as carbonate chemistry was strongly co-correlated with the other key environmental factors (nutrients, light).

  12. Regional Consortia for E-Resources: A Case Study of Deals in the South China Region

    Science.gov (United States)

    Chunrong, Luo; Jingfen, Wang; Zhinong, Zhou

    2010-01-01

    Purpose: The purpose of this paper is to analyse the current situation and the social and economic benefits from the consortia acquisitions of electronic resources by the China Academic Library and Information System (CALIS) South China Regional Centre and to recommend improvements for consortia acquisitions. Design/methodology/approach: Analyses…

  13. Statistical Prediction of the South China Sea Surface Height Anomaly

    Directory of Open Access Journals (Sweden)

    Caixia Shao

    2015-01-01

    Full Text Available Based on the simple ocean data assimilation (SODA data, this study analyzes and forecasts the monthly sea surface height anomaly (SSHA averaged over South China Sea (SCS. The approach to perform the analysis is a time series decomposition method, which decomposes monthly SSHAs in SCS to the following three parts: interannual, seasonal, and residual terms. Analysis results demonstrate that the SODA SSHA time series are significantly correlated to the AVISO SSHA time series in SCS. To investigate the predictability of SCS SSHA, an exponential smoothing approach and an autoregressive integrated moving average approach are first used to fit the interannual and residual terms of SCS SSHA while keeping the seasonal part invariant. Then, an array of forecast experiments with the start time spanning from June 1977 to June 2007 is performed based on the prediction model which integrates the above two models and the time-independent seasonal term. Results indicate that the valid forecast time of SCS SSHA of the statistical model is about 7 months, and the predictability of SCS SSHA in Spring and Autumn is stronger than that in Summer and Winter. In addition, the prediction skill of SCS SSHA has remarkable decadal variability, with better phase forecast in 1997–2007.

  14. Mangrove succession enriches the sediment microbial community in South China

    Science.gov (United States)

    Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

    2016-01-01

    Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession. PMID:27265262

  15. The South China Sea thermohaline structure and circulation

    Institute of Scientific and Technical Information of China (English)

    Peter C. Chu(朱伯承); Binbing Ma; Yuchun Chen

    2002-01-01

    In this study, we used the Navy' s Master Oceanographic Observation Data Set (MOODS), consisting of 116 019 temperature and 9 617 salinity profiles, during 1968~1984 to investigate the temporal and spatial variabilities of South China Sea thermohaline structures and circulation.For temperature, profiles were binned into 204 monthly data sets from 1968 to 1984 (17 years). For salinity, profiles were binned into 12 climatological monthly data sets due to the data paucity. A twoscale optimal interpolation method was used to establish a three-dimensional monthly-varying gridded data set from MOODS, covering the area of 5°~25°N and 105°~ 125°E and the depth from the surface to 400 m. After the gridded data set had been established, both composite analysis and the Empirical Orthogonal Function (EOF) analysis (for temperature only) were used to identify the major thermohaline fratures including annual mean, monthly anomalies, and interarmual thermal variabilities. The inverted monthly circulation pattern using the P - vector method is also discussed.

  16. Mangrove succession enriches the sediment microbial community in South China.

    Science.gov (United States)

    Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

    2016-01-01

    Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession. PMID:27265262

  17. Preozonation of bromide-bearing source water in south China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effectiveness of preozonation was evaluated on treating a bromide-bearing dam source water in south China through batch-scale experiments. Preozonation at ozone doses of 0.5-1.0 mg/L (at ozone consumption base) enhanced total organic carbon(TOC) removal through coagulation, and resulted in an almost linear reduction of ultraviolet absorbance at 254 nm (UV254). The removals of TOC (after coagulation) and UV254 at the ozone dose of 1.0 mg/L were 36% and 70%, respectively. Preozonation at an ozone dose between 0.5 and 1.0 mg/L resulted in the removal of disinfection byproducts formation potential (DBFP) including trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP) for about 50%. The removals of THMFP and HAAFP decreased with the further increase of ozone dose. Ozonation of bromide-bearing water (bromide concentration,34 μg/L) produced a bromate concentration under the detection limit(2 μg/L) at ozone doses < 1.5 mg/L. However, bromate >10 μg/L could be produced when the bromide concentration was increased to 96 μg/L.

  18. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  19. Exploration Prospect of Offshore Petroleum in China

    Institute of Scientific and Technical Information of China (English)

    Gong Zaisheng

    1994-01-01

    @@ Large Gas-Bearing Area in the Western South China Sea This area are composed of the west part of Jujiangkou Basin, Qiongdongnan Basin and Yinggehai Basin, with a total exploratory extent of approximately 140 thousand km2. Its petroleum geology conditions are favourable for formation of giant gasfields.

  20. Deep water bottom current deposition in the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    SHAO Lei; LI XueJie; GENG JianHua; PANG Xiong; LEI YongChang; QIAO PeiJun; WANG LiaoLiang; WANG HongBin

    2007-01-01

    There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m, extending from the NE to the SW, leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers suggests that these drifts propagated southwestward, following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current, which enters the northern SCS via the Bashi Strait. Once formed, the bottom currents transport sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity, the deep-sea sedimentary process in the northern SCS is complex.

  1. Recent progress of deep seismic experiments and studies of crustal structure in northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The South China Sea (SCS) is one of the largest marginal seas in the western Pacific. Its northern part has the features of a passive continental margin. The studies of deep crustal structure in this area are very important for understanding the tectonic nature, evolution history, basin formation of the northern margin, and the origin of the SCS. In the past decades, the deep seismic experiments of crustal studies in the northern SCS have gone through three stages, namely the sonobuoy, two-ship Expanding Spread Profile (ESP), and Ocean Bottom Hydrophone/Seismometer (OBH/OBS). Along the continental slope, the sonobuoy experiments provided useful information about the velocity structure of the upper crust, while the ESP data recorded for the first time the seismic signals from deep crustal structure and Moho interface. And the OBH/OBS profiles revealed the crustal structure in much greater detail. This paper first gives a brief historical review of these deep seismic experiments and studies, then a summary of the latest progress and important research results. The remaining problems and suggestions for further research work are presented as conclusive remarks.

  2. Interannual to decadal variation of spring sea level anomaly in the western South China Sea

    Science.gov (United States)

    Qiu, Fuwen; Fang, Wendong; Pan, Aijun; Cha, Jing; Zhang, Shanwu; Huang, Jiang

    2016-04-01

    Satellite observations of sea level anomalies (SLA) from January 1993 to December 2012 are used to investigate the interannual to decadal changes of the boreal spring high SLA in the western South China Sea (SCS) using the Empirical Orthogonal Function (EOF) method. We find that the SLA variability has two dominant modes. The Sea Level Changing Mode (SLCM) occurs mainly during La Niña years, with high SLA extension from west of Luzon to the eastern coast of Vietnam along the central basin of the SCS, and is likely induced by the increment of the ocean heat content. The Anticyclonic Eddy Mode (AEM) occurs mainly during El Niño years and appears to be triggered by the negative wind curl anomalies within the central SCS. In addition, the spring high SLA in the western SCS experienced a quasi-decadal change during 1993-2012; in other words, the AEM predominated during 1993-1998 and 2002-2005, while the La Niña-related SLCM prevailed during 1999-2001 and 2006-2012. Moreover, we suggest that the accelerated sea level rise in the SCS during 2005-2012 makes the SLCM the leading mode over the past two decades.

  3. Stratal Carbonate Content Inversion Using Seismic Data and Its Applications to the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of the relationship between the carbonate content and the stratal velocity and density, an exercise has been attempted using an artificial neural network on high-resolution seismic data for inversion of carbonate content with limited well measurements as a control. The method was applied to the slope area of the northern South China Sea near ODP Sites 1146 and 1148, and the results are satisfactory. Before inversion calculation, a stepwise regression method was applied to obtain six properties related most closely to the carbonate content variations among the various properties on the seismic profiles across or near the wells. These include the average frequency, the integrated absolute amplitude, the dominant frequency, the reflection time, the derivative instantaneous amplitude, and the instantaneous frequency. The results, with carbonate content errors of mostly ±5 % relative to those measured from sediment samples, show a relatively accurate picture of carbonate distribution along the slope profile. This method pioneers a new quantitative model to acquire carbonate content variations directly from high-resolution seismic data. It will provide a new approach toward obtaining substitutive high-resolution sediment data for earth system studies related to basin evolution, especially in discussing the coupling between regional sedimentation and climate change.

  4. Sea level rise projection in the South China Sea from CMIP5 models

    Institute of Scientific and Technical Information of China (English)

    HUANG Chuanjiang; QIAO Fangli

    2015-01-01

    Future potential sea level change in the South China Sea (SCS) is estimated by using 24 CMIP5 models under different representative concentration pathway (RCP) scenarios. By the end of the 21st century (2081–2100 relative to 1986–2005), the multimodel ensemble mean dynamic sea level (DSL) is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise (SLR) of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level (SSL) rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21st century, compared with the north and southwest shelves.

  5. Geochemistry and petrogenesis of volcanic rocks from Daimao Seamount (South China Sea) and their tectonic implications

    Science.gov (United States)

    Yan, Quanshu; Castillo, Paterno; Shi, Xuefa; Wang, Liaoliang; Liao, Lin; Ren, Jiangbo

    2015-03-01

    The South China Sea (SCS) experienced three episodes of seafloor spreading and left three fossil spreading centers presently located at 18°N, 17°N and 15.5°N. Spreading ceased at these three locations during magnetic anomaly 10, 8, and 5c, respectively. Daimao Seamount (16.6 Ma) was formed 10 my after the cessation of the 17°N spreading center. Volcaniclastic rocks and shallow-water carbonate facies near the summit of Daimao Seamount provide key information on the seamount's geologic history. New major and trace element and Sr-Nd-Pb isotopic compositions of basaltic breccia clasts in the volcaniclastics suggest that Daimao and other SCS seamounts have typical ocean island basalt-like composition and possess a 'Dupal' isotopic signature. Our new analyses, combined with available data, indicate that the basaltic foundation of Daimao Seamount was formed through subaqueous explosive volcanic eruptions at 16.6 Ma. The seamount subsided rapidly (> 0.12 mm/y) at first, allowing the deposition of shallow-water, coral-bearing carbonates around its summit and, then, at a slower rate (Hainan mantle plume. In contrast, lavas from contemporaneous seamounts in other marginal basins in the western Pacific are subduction-related.

  6. Dynamics and anthropogenic impacts of multiple karst flow systems in a mountainous area of South China

    Science.gov (United States)

    Luo, Mingming; Chen, Zhihua; Criss, Robert E.; Zhou, Hong; Huang, He; Han, Zhaofeng; Shi, Tingting

    2016-08-01

    The Xiangxi River basin, South China, is a steep terrane with well-developed karst features and an important Cambrian-Ordovician aquifer. Meteoric water in this mountainous area features a mean δ18O elevation gradient of -2.4 ‰/km. This gradient was used to estimate mean recharge elevations of 760 m for Shuimoxi (SMX) spring, 1,060 m for Xiangshuidong (XSD) spring, and 1,430 m for drill hole ZK03, indicating multiple flow paths in the Cambrian-Ordovician karst aquifer. Mean residence times of 230 and 320 days and ˜2 years were estimated for these features, respectively, using the damped running average model that predicts the isotopic variations in groundwater from those in precipitation. Groundwater in the regional karst flow system has the longest residence time, the highest recharge elevation, the longest flow paths, the lowest addition of anthropogenic components, and the greatest amount of water-rock interaction as indicated by its higher dissolved solids, Mg2+ concentrations and Mg/Ca ratios than the springs. In contrast, the local and shallow karst flow systems respond rapidly to recharge events. Artificial tracer tests prove that these shallow karst systems can also quickly transmit anthropogenic contaminants, indicating that they are highly vulnerable to human impacts, which include the enrichment of NO3 -. The intensity of water-rock interaction and groundwater vulnerability are mainly determined by the structure and dynamics of the multiple karst flow systems.

  7. Temporal and spatial distribution of the meiobenthic community in Daya Bay, South China Sea

    Science.gov (United States)

    Tang, L.; Li, H. X.; Yan, Y.

    2012-04-01

    Spatial and temporal biodiversity patterns of the meiobenthos were studied for the first time in Daya Bay, which is a tropical semi-enclosed basin located in the South China Sea. The abundance, biomass, and composition of the meiobenthos and the basic environmental factors in the bay were investigated. The following 19 taxonomic groups were represented in the meiofauna: Nematoda, Copepoda, Polychaeta, Oligochaeta, Kinorhyncha, Gastrotricha, Ostracoda, Bivalvia, Turbellaria, Nemertinea, Sipuncula, Hydroida, Amphipoda, Cumacea, Halacaroidea, Priapulida, Echinodermata, Tanaidacea, and Rotifera. Total abundance and biomass of the meiobenthos showed great spatial and temporal variation, with mean values of 993.57 ± 455.36 ind cm-2 and 690.51 ± 210.64 μg 10 cm-2, respectively. Nematodes constituted 95.60 % of the total abundance and thus had the greatest effect on meiofauna quantity and distribution, followed by copepods (1.55 %) and polychaetes (1.39 %). Meiobenthos abundance was significantly negatively correlated with water depth at stations (r=-0.747, Pnematodes with environmental parameters. Polychaete abundance was positively correlated with the bottom water temperature (r=0.456, Pnematodes and copepods, but a vertical distribution pattern for polychaetes was not as obvious. Based on the biotic indices and analyses of their correlations and variance, the diversity of this community was likely to be influenced by environmental variations.

  8. Water risk assessment for river basins in China based on WWF water risk assessment tools

    Science.gov (United States)

    Wei, N.; Qiu, Y.; Gan, H.; Niu, C.; Liu, J.; Gan, Y.; Zhou, N.

    2014-09-01

    Water resource problems, one of the most important environmental and socio-economic issues, have been a common concern worldwide in recent years. Water resource risks are attracting more and more attention from the international community and national governments. Given the current situations of water resources and the water environment, and the characteristics of water resources management and information statistics of China, this paper establishes an index system for water risk assessment in river basins of China based on the index system of water risk assessment proposed by the World Wide Fund For Nature (WWF) and German Investment and Development Co., Ltd (DEG). The new system is more suitable for Chinese national conditions and endorses the international assessment index. A variety of factors are considered to determine the critical values of classification for each index, and the indexes are graded by means of 5-grade and 5-score scales; the weights and calculation methods of some indexes are adjusted, with the remaining indexes adopting the method of WWF. The Weighted Comprehensive Index Summation Process is adopted to calculate the integrated assessment score of the river basin. The method is applied to the Haihe River basin in China. The assessment shows that the method can accurately reflect the water risk level of different river basins. Finally, the paper discusses the continuing problems in water risk assessment and points out the research required to provide a reference for further study in this field.

  9. The impacts of climate change on water resources in the Second Songhua River Basin, China

    Science.gov (United States)

    Yu, J. S.; Yao, X. L.; Sun, W. C.; Li, Z. J.

    2016-08-01

    The Northeast China Plain is one of the main grain growing regions in China. Due to the high latitude and black soil ecological system, the crop growth in there is vulnerable to climate change, which makes it important to evaluate the influences of climate change on water resources. In this study, the influences of climate change on water resources of a typical basin in northeast China, the Second Songhua River Basin were assessed using the SWAT model. Ensemble downscaled output from sixteen GCMs for A1B emission scenario in 2050s was adopted as the regional climate scenario and was used to drive SWAT model to predict hydrological changes. The prediction shows that mean evapotranspiration of whole basin increases in most time of a year. Stream flow of Fuyu gauging station downstream this basin exhibits a decrease trend from April to June, November and December, and increases in the remaining period of the year. It is indicated that water resources may not be sufficient in spring for irrigation and the possibility of flood in summer may increases, indicating countermeasures should be made to ensure agricultural water use and prevent possible damages of flood on crop.

  10. Structure of the Dayangshu Basin in Northeast China Inferred from Magnetotelluric Data

    Science.gov (United States)

    Cao, J.; Sun, Y.; Li, X.; Chen, S.

    2005-12-01

    The Dayangshu basin is a NNE trending fault-bounded basin, located at longitude 123°21' - 125°38' east and latitude 47°55' - 50°59' north within the southern part of the Xingan fold system. It is one of the largest sedimentary basins in Northeast China with an area of 15,460 km2. The sedimentary rock in the basin is approximately 3,000 m thick, and is composed mainly of clastic rocks and volcanic rocks. The base of the basin consists mainly of Paleozoic low-grade metamorphic rocks. In the early 1990s, the Daqing Oilfield Company started petroleum exploration programs in the area. By the end of 1990s, gravity, magnetic, magnetotelluric (MT), and 2D seismic reflection measurements had been carried out in the basin and several prospects had been drilled. It has been determined that the majority, about 75%, of the basin is composed of volcanic rocks. However, the location and extent of the lava and main hydrocarbon source rock are still unclear. The distribution of these materials is very important for understanding the geological history and evaluating the petroleum resource capacity of the basin. The volcanic rocks within the basin are highly magnetic. The average susceptibility of the lava in the basin is about 0.18 SI units. It has been demonstrated that highly magnetic rocks significantly affect the MT response. By simultaneously inverting MT data for electric resistivity and magnetic susceptibility estimate, we develop a new approach for mapping magnetic strata. We apply the approach to the interpretation of MT data collected at 3,243 sites within the basin, and obtain a volcanic rock distribution model characterized by high susceptibility. The model shows that volcanic rocks are predominantly located at the boundary and middle of the basin. The volcanic rocks located at the middle of the basin cut the basin into southern, middle and northern sub-depressions. The hydrocarbon source rocks should be buried in the sub-depressions, and the lava close to the

  11. Analysis of dry/wet conditions in the Gan River Basin, China, and their association with large-scale atmospheric circulation

    Science.gov (United States)

    Zhang, Yuqing; You, Qinglong; Lin, Houbo; Chen, Changchun

    2015-10-01

    Droughts and floods are natural phenomena that occur when water availability is significantly below or above normal levels over a specific period. In recent years, the Gan River Basin has frequently been threatened by droughts and floods, and it is important to evaluate the characteristics of dry/wet conditions for better water resource management and disaster mitigation in this region. On the basis of precipitation and temperature data for the period 1964-2013 from 40 meteorological stations across the basin, the variability of dry/wet conditions was analyzed using the standardized precipitation evapotranspiration index (SPEI). In addition, the standardized streamflow index (SSI) and large-scale atmospheric circulation patterns calculated from NCEP/NCAR reanalysis data were used to further explore and evaluate temporal variations, spatial patterns, and possible mechanism responsible for the formation of dry/wet conditions in the basin. The results indicated that robust coefficients between monthly SSI and SPEI exist at multiple timescales. The best correlation coefficients were found at timescales of 2-3 months, which better reflect the intensity and magnitude of seasonal dry/wet conditions. Application of a 3-month SPEI for the dry (July-September) and wet (April-June) seasons indicated that severe dry/wet episodes were easy to occur in the northern part of the basin. The difference between composites of anomalous dry/wet seasons shows that both a positive height anomaly at 500 hPa and a very little water vapor flux influence the basin during the dry season of anomalous years, which can lead to the occurrence of drought events in the basin. However, during the wet season of anomalous years, geopotential height anomalies caused by areas of high pressure in the south (South China Sea) and areas of low pressure in the north (Mongolia), are responsible for the transport of copious amounts of water vapor from both the Bay of Bengal and the South China Sea. Under these

  12. Interannual Variability of Autumn Precipitation over South China and its Relation to Atmospheric Circulation and SST Anomalies

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The interannual variability of autumn precipitation over South China and its relationship with atmospheric circulation and SST anomalies are examined using the autumn precipitation data of 160 stations in China and the NCEP-NCAR reanalysis dataset from 1951 to 2004. Results indicate a strong interannual variability of autumn precipitation over South China and its positive correlation with the autumn western Pacific subtropical high (WPSH). In the flood years, the WPSH ridge line lies over the south of South China and the strengthened ridge over North Asia triggers cold air to move southward. Furthermore, there exists a significantly anomalous updraft and cyclone with the northward stream strengthened at 850 hPa and a positive anomaly center of meridional moisture transport strengthening the northward warm and humid water transport over South China. These display the reverse feature in drought years. The autumn precipitation interannual variability over South China correlates positively with SST in the western Pacific and North Pacific, whereas a negative correlation occurs in the South Indian Ocean in July. The time of the strongest lag-correlation coefficients between SST and autumn precipitation over South China is about two months, implying that the SST of the three ocean areas in July might be one of the predictors for autumn precipitation interannual variability over South China. Discussion about the linkage among July SSTs in the western Pacific, the autumn WPSH and autumn precipitation over South China suggests that SST anomalies might contribute to autumn precipitation through its close relation to the autumn WPSH.

  13. Seismic tomography beneath the orogenic belts and adjacent basins of northwestern China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave recorded in seismic networks in Xinjiang, Qinghai, Gansu of China and Kyrgyzstan. The velocity images of upper crust demonstrate the tectonic framework on the ground surface. High velocities are observed beneath orogenic belts, and low velocities are observed in the basins and depressions that are obviously related to unconsolidated sediments. The velocity image in mid-crust maintains the above features, and in addition low velocities appear in some earthquake regions and a low velocity boundary separates the western Tianshan Mts. from eastern Tianshan Mts. The orogenic belts and the northern Tibetan plateau have a Moho depth over 50 km, whereas the depths of the Moho in basins and depressions are smaller than 50 km. The velocity images of upper mantle clearly reveal the colliding relationship and location of deep boundaries of the continental blocks in northwestern China, indicating a weakness of the upper mantle structure of orogenic belts. The top depth of upper mantle asthenosphere varies from place to place. It seems shallower under the northern Tibetan plateau, Altay and Qilian Mts., and deeper under the Tarim and Tianshan regions. Hot mantle probably rose to the bottom of some orogenic belts along tectonic boundaries when continental blocks collided to each other. Therefore their dynamic features are closely correlated to the formation and evolution of orogenic belts in northwestern China.

  14. Hypersaline and anoxia in the Devonian Frasnian-Famennian transition :Molecular fossil and mineralogical evidence from Guangxi ,South China

    Institute of Scientific and Technical Information of China (English)

    GONG Yiming; XU Ran; FENG Qi; ZHANG Lijun; MA Huizhen; ZENG Jianwei

    2007-01-01

    Abundant normal alkanes,isoprenoid hydrocarbons,terpanes and steranes were detected in 23 samples taken from the carbonate platform to basin facies in the Devonian Frasnian-Famennian (F-F) transition of Guangxi,South China.They were mainly derived from the phytoplankton or bacteria and algae.Molecular stratigraphic parameters,abundant micron gypsums and pyrite framboids show that hypersaline and anoxia prevailed in the F-F transition,the highly stressed environments occurred near the F-F boundary.Orbital cyclostratigraphic studies indicate that the hypersaline and anoxia prevailed in the F-F transition spanned an interval at least from the Palmatolepis linguiformis conodont Zone to the Middle Palmatolepis triangularis conodont Zone and lasted about 1.2 Ma.The Devonian marine ecosystem underwent Early Devonian gradual optimization,Middle Devonian to the F-F transitional stepwise deterioration and late Famennian recovery.A positive feedback among higher surface ocean temperatures,hypersaline,water column anoxia, enhanced nutrient regeneration,phytoplankton productivity and eutrophication was probably substantial in the F-F transition in Guangxi,South China,even in other regions of the world,such as Holy Cross Mountains of Poland,Montagne Noire in southern France,Alberta in Canada.The point that should be emphasized is that the decisive and direct causes of the F-F transitional mass extinction would be the stepwise deterioration of the marine ecosystem since the Middle Devonian other than a bolide impact on the earth.The hypersaline and anoxia prevailed in the F-F transition favor the formation and preservation of hydrocarbon source rocks in South China.

  15. Typical synoptic situations and their impacts on the wintertime air pollution in the Guanzhong basin, China

    Science.gov (United States)

    Bei, Naifang; Li, Guohui; Huang, Ru-Jin; Cao, Junji; Meng, Ning; Feng, Tian; Liu, Suixin; Zhang, Ting; Zhang, Qiang; Molina, Luisa T.

    2016-06-01

    Rapid industrialization and urbanization have caused severe air pollution in the Guanzhong basin, northwestern China, with heavy haze events occurring frequently in recent winters. Using the NCEP reanalysis data, the large-scale synoptic situations influencing the Guanzhong basin during wintertime of 2013 are categorized into six types to evaluate the contribution of synoptic situations to the air pollution, including "north-low", "southwest-trough", "southeast-high", "transition", "southeast-trough", and "inland-high". The FLEXPART model has been utilized to demonstrate the corresponding pollutant transport patterns for the typical synoptic situations in the basin. Except for "southwest-trough" and "southeast-high" (defined as favorable synoptic situations), the other four synoptic conditions (defined as unfavorable synoptic situations) generally facilitate the accumulation of air pollutants, causing heavy air pollution in the basin. In association with the measurement of PM2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) in the basin, the unfavorable synoptic situations correspond to high PM2.5 mass concentrations or poor air quality and vice versa. The same analysis has also been applied to winters of 2008-2012, which shows that the basin was mainly influenced by the unfavorable synoptic situations during wintertime leading to poor air quality. The WRF-CHEM model has further been applied to simulate the selected 6 days representing the typical synoptic situations during the wintertime of 2013, and the results generally show a good agreement between the modeled distributions and variations of PM2.5 and the corresponding synoptic situations, demonstrating reasonable classification for the synoptic situations in the basin. Detailed meteorological conditions, such as temperature inversion, low-level horizontal wind speed, and planetary boundary layer, all contribute to heavy air pollution events in the basin under unfavorable synoptic conditions

  16. Probabilistic forecasting of seasonal drought behaviors in the Huai River basin, China

    Science.gov (United States)

    Xiao, Mingzhong; Zhang, Qiang; Singh, Vijay P.; Chen, Xiaohong

    2016-01-01

    The Huai River basin is one of the major supplier of agricultural products in China, and droughts have critical impacts on agricultural development. Good knowledge of drought behaviors is of great importance in the planning and management of agricultural activities in the Huai River basin. With the copula functions to model the persistence property of drought, the probabilistic seasonal drought forecasting models have been built in the Huai River basin. In this study, droughts were monitored by the Standardized Precipitation Evapotranspiration Index (SPEI) with the time scales of 3, 6, and 9 months, and their composite occurrence probability has been used to forecast the seasonal drought. Results indicated that the uncertainty related to the predicted seasonal drought is larger when more severe droughts occurred in the previous seasons, and the severe drought which occurs in summer and autumn will be more likely to be persistent in the next season while the severe drought in winter and spring will be more likely to be recovered in the subsequent season. Furthermore, given the different drought statuses in the previous season, spatial patterns of the predicted drought events with the largest occurrence probability have also been investigated, and results indicate that the Huai River basin is vulnerable to the extreme drought in most parts of the basin, e.g., the severe drought in winter will be more likely to be persistent in spring in the central part of the southern Huai River basin. Such persistent drought events pose serious challenges for planning and management of agricultural irrigation, then results of the study will be valuable for the planning of crop cultivation or mitigation of the losses caused by drought in the Huai River basin, China.

  17. Airburst Impact Origin Hypothesis of Taihu Lake Basin in Southeast of China in Around 7000 Years ago

    Science.gov (United States)

    Xie, Z.; Zuo, S.

    2013-08-01

    The paper is to report investigation on unique morphology, occurrence, distribution, and mineralogy of siderite concretions found in Taihu Lake, Southeast of China, and discuss airburst impact origin hypothesis of Taihu Lake basin in ~7000 years ago.

  18. Tectonic and eustatic control on the distribution of black-shale source beds in the Wufeng and Longmaxi formations (Ordovician-Silurian),South China

    Institute of Scientific and Technical Information of China (English)

    SU Wenbo; ZHAO Huijing; LI Zhiming; Ettensohn F.R.; Johnson M.E.; Huff W.D.; WANG Wei; MA Chao; LI Lu; ZHANG Lei

    2007-01-01

    It is known that high-quality,black-shale source rocks occur in the uppermost Ordovician Wufeng Formation and in the lowermost Silurian Longmaxi Formation in South China.Hence,it is important to understand their lithostratigraphy and the controls on their deposition.A review of lithostratigraphic criteria for subdividing the two adjacent formations provides new regional correlations between the formations and related stratigraphic successions and facies.Both the black shales and the related,overlying flysch deposits at the Ordovician-Silurian transition in South China appear to have migrated northwestward in time and space,reflecting probable flexural control in a foreland basin that developed in response to subduction-type orogeny southeast of the Yangtze block.The black shales also contain K-bentonites from explosive,felsic-intermediate volcanism,the distribution of which also supports orogeny to the southeast.Finally,the analysis of sequence stratigraphy,which shows that the initiation of transgressive system tracts (TST) and condensed section (CS) in the related third-order sequences coincided with the two black-shale horizons respectively,indicates that the main controlling factors for the deposition of the Ordovician-Silurian black shales in South China are (1)northwestwardly migrating,foreland-basin subsidence caused by deformational loading related to episodic accretion of the Cathaysia block to the Yangtze block during this period,and (2) the anoxic,sediment-starved water column caused by rapid rise of the sea-level during the two successive phases of third-order global sea-level rise near the Ordovician-Silurian transition in South China.In future exploration for hydrocarbon source rocks in the area,it is important to consider likely flexural and eustatic causes for subsiding,deep,anoxic seas in recognizing other source rock intervals,and our understanding of the Wufeng and Longmaxi formations may serve as models for future source rock exploration.

  19. Investigating Effects of Monsoon Winds on Hydrodynamics in the South China Sea

    Science.gov (United States)

    Chua, V. P.

    2013-12-01

    The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. The circulation in South China Sea is subjected to seasonal and inter-annual variations of tidal and meteorological conditions. The effects of monsoon winds on hydrodynamics is investigated by applying spectral and harmonic analysis on surface elevation and wind data at stations located in the South China Sea. The analysis indicates varying responses to the seasonal monsoon depending on the location of the station. At Kaohsiung (located in northern South China Sea off Taiwan coast), tides from the Pacific Ocean and the southwest monsoon winds are found to be dominant mechanisms. The Kota Kinabalu and Bintulu stations, located to the east of South China Sea off Borneo coast, are influenced by low energy complex winds, and the shallow bottom bathymetry at these locations leads to tidal energy damping compared to other stations. The tidal dynamics at Tioman, located in southern South China Sea off Malaysia coast, are most responsive to the effects of the northeast monsoon. The complexity of our problem together with the limited amount of available data in the region presents a challenging research topic. An unstructured-grid SUNTANS model is employed to perform three-dimensional simulations of the circulation in South China Sea. Skill assessment of the model is performed by comparing model predictions of the surface elevations and currents with observations. The results suggest that the quality of the model prediction is highly dependent on horizontal grid resolution and coastline accuracy. The model may be used in future applications to investigate seasonal and inter-annual variations in hydrodynamics.

  20. Tectonic and Hydrocarbon Accumulation Elements Characteristics of the Tethyan Realm in South China

    Institute of Scientific and Technical Information of China (English)

    YU Yixin; TANG Liangjie; YIN Jinyin; DONG Li; WANG Pengwan; ZHOU Yan

    2009-01-01

    The evolution of the global Tethys Sea can be classified into three stages, Proto-Tethys, Paleo-Tethys and Neo-Tethys. The Tethyan realm has distinctive features of zonations and segmentations along north-south and east-west, respectively, and has variable richness in oil and gas. The petroleum geological conditions of Tethys are complicated, partly represented by multi-layer of source and seal rocks, and reservoirs. The hydrocarbon accumulation elements and periods of the Tethyan realm show gradually younger from west to east and north to south. South China is located in the north belt and Yangtze segment of the Tethyan realm, and its polycyclic tectonic movements were governed by the Tethyan and Pacific realms. The blocks in South China rotated clockwise and counter-clockwise during their drift northward from Gondwana. The belts and segmentations of Tethys in South China are also clear, with six tectonic belts including: Chuxiong-Sichuan; middle Guizhou-Hunan-Hubei; lower Yangtze; Xuefeng-Jiangnan; Guangxi-Hunan-Jiangxi; and Cathaysia. Numerous faults, including compressional, compressional-shear, extensional, extensional-shear and shear are well developed in South China. The fault strikes are mainly NE, NW and NS, in which the NE is the dominant direction. Lower, middle and upper hydrocarbon assemblages, respectively corresponding to Proto-, Paleo-and Neo-Tethys, formed in the Tethyan realm of South China with the lower and middle having excellent hydrocarbon accumulation conditions. An integrated analysis of tectonic evolution, superimposed deformation and later hydrocarbon preservation shows that during the Neo-Tethyan stage in South China, continental sediments were deposited and experienced intense tectonic deformation, which had resulted in different hydrocarbon pool-forming features from those of the Neo-Tethyan realm.

  1. WATER QUALITY MODELING AND POLLUTION CONTROL FOR THE EASTERN ROUTE OF SOUTH TO NORTH WATER TRANSFER PROJECT IN CHINA

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; WANG Yan-ying; WANG Pei-fang

    2006-01-01

    South to North Water Transfer Project in China is the largest project over centuries to solve the water shortage problem in vast areas of northern China. It comprises of three routes: the eastern, central and western route and this study mainly focused on the eastern route. As water quality is the key factor for the eastern route, this paper examined the main factors influencing water quality of the main route south of the Yellow River, by investigating the point source, non-point source (diffusive source) and internal source pollutions along the main eastern route and in its drainage basins, and assessing the current water quality in the waterways. According to the complicated and combined systems of rivers and lakes in this route, one-dimensional water quantity and quality model for rivers and two-dimensional model for lakes were developed to simulate the hydrodynamic and pollutant transport processes. The numerical method and model algorithm were described. The values of model parameters were estimated by using field-monitoring data along the main route and the inverse modeling technique. Established models were employed to predict the degradations of CODMn and NH4+-N in the main stream, under the conditions of current pollution loads and different hydrologic conditions. Schemes were present for controlling total quantities of pollutants from point source and non-point source along the main route to secure water quality for the eastern route.

  2. Spatio-temporal carbon isotope variation during the Ediacaran period in South China and its impact on bio-evolution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Ediacaran period is characterized by the extremely negative carbon isotope anomalies and great biotic evolution in Earth history. At least four negative carbon isotope anomalies have been reported from this interval in South China so far. It is traditionally argued that the isotope variations can be used as a useful tool for global correlation of Ediacaran succession; however, more and more researches argued against this idea. We reviewed the previously published carbon isotope data in South China, and distributed the mean values of a certain time to the paleogeographic maps. The results show that the carbon isotope values (δ 13C) vary greatly in different environments, but a clear tendency of becoming lighter from shallow platform to deep basin, with a maximum variation up to 11‰. Moreover, the important changes in Ediacaran biota, marked by the introducing of new taxa or ecologic groups, seemed to always postdate the negative anomalies but coincide with the positive shift. If the negative excursions represented the oxidation of a large dissolved organic carbon (DOC) reservoir in the ocean, the diverse Ediacaran organisms and the carbon isotope anomalies may suggest totally different environments: oxic and anoxic/euxinic. We also suggest that the elimination of euxinic state through precipitation of pyrites is one of the important environment factors in prompting the Ediacaran bio-evolution.

  3. Clay mineralogy of the riverine sediments of Hainan Island, South China Sea: Implications for weathering and provenance

    Science.gov (United States)

    Hu, Bangqi; Li, Jun; Cui, Ruyong; Wei, Helong; Zhao, Jingtao; Li, Guogang; Fang, Xisheng; Ding, Xue; Zou, Liang; Bai, Fenglong

    2014-12-01

    Clay mineralogy of 54 fluvial samples collected from 20 major rivers on Hainan Island are investigated in order to determine compositional changes of clay minerals and to assess the weathering processes. The clay mineral assemblages consist dominantly of kaolinite (31-66%), with a lesser abundance of chlorite (22-44%) and illite (4-33%), and a trace amount of smectite (0-15%). Fluvial sediments from the east and northwest of Hainan Island are characterized by a higher kaolinite content and illite chemical index and poorer illite crystallinity than those from southwest Hainan. Only minor smectite (mean of 7%) occurs in the sediments from west Hainan; smectite is total lacking in east Hainan. Compared with the adjacent basins, Hainan Island is characterized by moderate to intensive chemical weathering with strong hydrolysis. Our results suggest that rainfall is the principal factor controlling the intensity of chemical weathering on Hainan Island, with more intense chemical weathering occurring in eastern and northwestern Hainan. Another practical implication of this study is that it provides a "missing" end member (Hainan Island) in the provenance discrimination study focused on the northern South China Sea (SCS). Hainan fine-grained sediments likely play an important role in providing clay minerals to the northern SCS carried by the South China Sea Warm Current (SCSWC) during the summer.

  4. Moonrise: Sampling the South Pole-Aitken Basin to Address Problems of Solar System Significance

    Science.gov (United States)

    Zeigler, R. A.; Jolliff, B. L.; Korotev, R. L.; Shearer, C. K.

    2016-01-01

    A mission to land in the giant South Pole-Aitken (SPA) Basin on the Moon's southern farside and return a sample to Earth for analysis is a high priority for Solar System Science. Such a sample would be used to determine the age of the SPA impact; the chronology of the basin, including the ages of basins and large impacts within SPA, with implications for early Solar System dynamics and the magmatic history of the Moon; the age and composition of volcanic rocks within SPA; the origin of the thorium signature of SPA with implications for the origin of exposed materials and thermal evolution of the Moon; and possibly the magnetization that forms a strong anomaly especially evident in the northern parts of the SPA basin. It is well known from studies of the Apollo regolith that rock fragments found in the regolith form a representative collection of many different rock types delivered to the site by the impact process (Fig. 1). Such samples are well documented to contain a broad suite of materials that reflect both the local major rock formations, as well as some exotic materials from far distant sources. Within the SPA basin, modeling of the impact ejection process indicates that regolith would be dominated by SPA substrate, formed at the time of the SPA basin-forming impact and for the most part moved around by subsequent impacts. Consistent with GRAIL data, the SPA impact likely formed a vast melt body tens of km thick that took perhaps several million years to cool, but that nonetheless represents barely an instant in geologic time that should be readily apparent through integrated geochronologic studies involving multiple chronometers. It is anticipated that a statistically significant number of age determinations would yield not only the age of SPA but also the age of several prominent nearby basins and large craters within SPA. This chronology would provide a contrast to the Imbrium-dominated chronology of the nearside Apollo samples and an independent test of

  5. Major element,trace element,and Sr,Nd and Pb iso-tope studies of Cenozoic basalts from the South China Sea

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The whole rock K-Ar ages of basalts from the South China Sea basin vary from 3.8 to 7.9 Ma, which suggest that intra-plate volcanism after the cessation of spreading of the South China Sea (SCS) is comparable to that in adjacent regions around the SCS, i.e., Leiqiong Peninsula, northern margin of the SCS, Indochina block, and so on. Based on detailed petrographic studies, we selected many fresh ba-saltic rocks and measured their major element, trace element, and Sr-Nd-Pb isotope compositions. Geochemical characteristics of major element and trace element show that these basaltic rocks belong to alkali basalt magma series, and are similar to OIB-type basalt. The extent of partial melting of mantle rock in source region is very low, and magma may experience crystallization differentiation and cu-mulation during the ascent to or storing in the high-level magma chamber. Sr-Nd-Pb isotopic data of these basaltic rocks imply an inhomogeneous mantle below the South China Sea. The nature of magma origin has a two end-member mixing model, one is EM2 (Enriched Mantle 2) which may be originated from mantle plume, the other is DMM (Depleted MORB Mantle). Pb isotopic characteristics show the Dupal anomaly in the South China Sea, and combined with newly found Dupal anomaly at Gakkel ridge in Arctic Ocean, this implies that Dupal anomaly is not only limited to South Hemisphere. In variation diagrams among Sr, Nd and Pb, the origin nature of mantle below the SCS is similar to those below Leiqiong peninsula, northern margin of the SCS and Indochina peninsula, and is different from those below north and northeast China. This study provides geochemical constraints on Hainan mantle plume.

  6. Influence of overpressure on coalbed methane reservoir in south Qinshui basin

    Institute of Scientific and Technical Information of China (English)

    LIU Shaobo; SONG Yan; ZHAO Menjun

    2005-01-01

    In theory, from the high temperature and pressure during the coal generating gas to the present low temperature and pressure of coalbed methane reservoir, the accumulation of coalbed methane was from oversaturated to undersaturated. The gas content of the coalbed methane reservoir in the south Qinshui basin was 12-35.7 m3/t. According to the isotherm and measured gas content of No. 3 coal,the adsorbed gas content in some wells was highly saturated and oversaturated, which was hard to theoretically understand. In addition, there were no thermogenic and biogenic gases at the late stage in the south Qinshui basin. This article proposed that the overpressure was the main reason for the present high saturation of the coalbed methane reservoir. In early Cretaceous, the coalbed methane reservoir was characterized by overpressure and high saturation caused by gas generation from coal measure source rocks. In late Cretaceous, the coalbed methane reservoir was rapidly uplifted,and with the temperature and pressure decreasing, the pressure condition of adsorbed gas changed from overpressure to normal-under pressure, which resulted in the high saturation and gas content in the present coalbed methane reservoir.

  7. Hydrological cycle over South and Southeast Asian river basins as simulated by PCMDI/CMIP3 experiments

    OpenAIRE

    Hasson, S.; Lucarini, V.; Pascale, S.

    2013-01-01

    We investigate how CMIP3 climate models describe the hydrological cycle over four major South and Southeast Asian river basins (Indus, Ganges, Brahmaputra and Mekong) for the XX, XXI, and XXII centuries. For the XX century, models' simulated water balance and total runoff quantities are neither consistent with the observed mean river discharges nor among the models. Most of the models underestimate the water balance for the Ganges, Brahmaputra and Mekong basin and overestimate it for the Indu...

  8. Intercomparison of three South China Sea circulation models

    Institute of Scientific and Technical Information of China (English)

    DU Yan; WANG Dongxiao; ZHOU Weidong; WANG Weiqiang; LIU Xiongbin

    2004-01-01

    Three numerical oceanic circulation models: POM(Princeton ocean model), MICOM(Miami isopycnal coordinates ocean model) and GFDL model, which adopt sigma coordinate, isopycnal coordinate and depth coordinate respectively,are used in the South China Sea(SCS) circulation modeling. Model domain has the same topography, grid resolution,initial conditions and surface boundary conditions. The maximum ocean depth is set as 1000 m. Grid resolution is 0.5°×0.5°.Initial conditions are supplied by climatological temperature and salinity data in January. Climatological wind stress, surface temperature and salinity are used as surface forcing. Lateral boundaries take enclosed boundary conditions artificially. Focusing on the common point of different ocean circulation models, the circulation pattern in winter and summer, sea surface height in the northern SCS, seasonal cycle of the mixed layer thickness in the southem SCS,barotropic stream function in winter are selected to carry out intercomparison. In winter, a strong cyclonic gyre occupies the whole SCS. In summer, a strong anticyclonic gyre occupies the southern SCS and a weak cyclonic gyre occupies the northern SCS. The thickness of the mixed layer shows bimodal features in the southern SCS. Sea surface height anomaly(SSHA) in the northern SCS has an eastward propagating feature, in agreement with the remote sensing observation. Barotropic stream functions indicate that the circulation of the upper ocean is mainly forced by inputting of wind stress curl under closed boundary conditions. In addition, three models also show distinct differences. The basinscale circulation fiom MICOM is distinct. Output of POM has more mesoscale eddies than others. GFDL model seems good at simulating westward intensification.

  9. Early Cambrian pentamerous cubozoan embryos from South China.

    Directory of Open Access Journals (Sweden)

    Jian Han

    Full Text Available BACKGROUND: Extant cubozoans are voracious predators characterized by their square shape, four evenly spaced outstretched tentacles and well-developed eyes. A few cubozoan fossils are known from the Middle Cambrian Marjum Formation of Utah and the well-known Carboniferous Mazon Creek Formation of Illinois. Undisputed cubozoan fossils were previously unknown from the early Cambrian; by that time probably all representatives of the living marine phyla, especially those of basal animals, should have evolved. METHODS: Microscopic fossils were recovered from a phosphatic limestone in the Lower Cambrian Kuanchuanpu Formation of South China using traditional acetic-acid maceration. Seven of the pre-hatched pentamerous cubozoan embryos, each of which bears five pairs of subumbrellar tentacle buds, were analyzed in detail through computed microtomography (Micro-CT and scanning electron microscopy (SEM without coating. RESULTS: The figured microscopic fossils are unequivocal pre-hatching embryos based on their spherical fertilization envelope and the enclosed soft-tissue that has preserved key anatomical features arranged in perfect pentaradial symmetry, allowing detailed comparison with modern cnidarians, especially medusozoans. A combination of features, such as the claustrum, gonad-lamella, suspensorium and velarium suspended by the frenula, occur exclusively in the gastrovascular system of extant cubozoans, indicating a cubozoan affinity for these fossils. Additionally, the interior anatomy of these embryonic cubozoan fossils unprecedentedly exhibits the development of many new septum-derived lamellae and well-partitioned gastric pockets unknown in living cubozoans, implying that ancestral cubozoans had already evolved highly specialized structures displaying unexpected complexity at the dawn of the Cambrian. The well-developed endodermic lamellae and gastric pockets developed in the late embryonic stages of these cubozoan fossils are comparable with

  10. The Anisotropic Structure of South China Sea: Using OBS Data to Constrain Mantle Flow

    Science.gov (United States)

    Li, L.; Xue, M.; Yang, T.; Liu, C.; Hua, Q.; Xia, S.; Huang, H.; Le, B. M.; Huo, D.; Pan, M.

    2015-12-01

    The dynamic mechanism of the formation of South China Sea (SCS) has been debated for decades. The anisotropic structure can provide useful insight into the complex evolution of SCS by indicating its mantle flow direction and strength. In this study, we employ shear wave splitting methods on two half-year seismic data collected from 10 and 6 passive source Ocean Bottom Seismometers (OBS) respectively. These OBSs were deployed along both sides of the extinct ridge in the central basin of SCS by Tongji University in 2012 and 2013 respectively, which were then successfully recovered in 2013 and 2015 respectively. Through processing and inspecting the global and regional earthquakes (with local events being processing) of the 2012 dataset, measurements are made for 2 global events and 24 regional events at 5 OBSs using the tangential energy minimization, the smallest eigenvalue minimization, as well as the correlation methods. We also implement cluster analysis on the splitting results obtained for different time windows as well as filtered at different frequency bands. For teleseismic core phases like SKS and PKS, we find the fast polarization direction beneath the central basin is approximately NE-SW, nearly parallel to the extinct ridge in the central basin of SCS. Whereas for regional events, the splitting analysis on S, PS and ScS phases shows much more complicated fast directions as the ray path varies for different phases. The fast directions observed can be divided into three groups: (1) for the events from the Eurasia plate, a gradual rotation of the fast polarization direction from NNE-SSW to NEE-SWW along the path from the inner Eurasia plate to the central SCS is observed, implying the mantle flow is controlled by the India-Eurasia collision; (2) for the events located at the junction of Pacific plate and Philippine plate, the dominant fast direction is NW-SE, almost perpendicular to Ryukyu Trench as well as sub-parallel to the absolute direction of

  11. Physical Properties of the Triassic Host Strata and Their Relations With Gold Mineralization in Youjiang Rift,South China

    Institute of Scientific and Technical Information of China (English)

    张景荣; 陆建军; 等

    1998-01-01

    Micro-fine disseminated gold deposits are hosted in the Triassic Baipeng Formation (argillaceous siltstone and arenaceous mudstone)in the Youjiang Rift,South China.Physical properties(grain size,specific surface,porosity and permeability)of the host rocks are studied with respect to ore-fluid cirulation,water-rock reaction and the effective volume from which ore-components could be extracted.On this basis,it is considered that the ore-fluid and oremetals were extracted mainly from the strata and hydrothermal solutions,tending to move to wards low-energy sites,depositing their gold in fault zones at the margins of the basin and in the circle fracture systems around underwater uplifts.The gold deposits resulted from the deepcirculation of hydrothermal solutions,Probably aided by multi-stage superimposition The quantites of ore-fluid necessary to form the deposits were estimated.

  12. Evidence for water exchange between the South China Sea and the Pacific Ocean through the Luzon Strait

    Institute of Scientific and Technical Information of China (English)

    曲堂栋

    2002-01-01

    An analysis of historical oxygen data provides evidence on the water exchange between the South China Sea(SCS)and the Pacific Ocean(PO).In the vicinity of the Luzon Strait(LS),the dissolved oxygen concentration of sea water is found to be lower on the Pacific side than on the SCS side at depths between 700 and 1500 rn(intermediate layer),while the situation is reversed above 700 rn(upper layer)and below 1 500 rn(deep layer).The evidence suggests that water exits the SCS in the intermediate layer but enters it from the Pacific in both the upper and the deep layers,supporting the earlier speculation that the Luzon Strait transport has a sandwiched structure in the vertical.Within the SCS basin,the oxygen distribution indicates widespread vertical rnovernent,including the upwelling in the intermediate layer and the downwelling in the deep layer.

  13. Radiogenic heat production in sedimentary rocks of the Gulf of Mexico Basin, south Texas

    Science.gov (United States)

    McKenna, T.E.; Sharp, J.M.

    1998-01-01

    Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we calculate radiogenic heat production for Stuart City (Lower Cretaceous) limestones, Wilcox (Eocene) sandstones and mudrocks, and Frio (Oligocene) sandstones and mudrocks from south Texas. Heat production rates range from a low of 0.07 ?? 0.01 ??W/m3 in clean Stuart City limestones to 2.21 ?? 0.24??W/m3 in Frio mudrocks. Mean heat production rates for Wilcox sandstones, Frio sandstones, Wilcox mudrocks, and Frio mudrocks are 0.88, 1.19, 1.50, and 1.72 ??W/m3, respectively. In general, the mudrocks produce about 30-40% more heat than stratigraphically equivalent sandstones. Frio rocks produce about 15% more heat than Wilcox rocks per unit volume of clastic rock (sandstone/mudrock). A one-dimensional heat-conduction model indicates that this radiogenic heat source has a significant effect on subsurface temperatures. If a thermal model were calibrated to observed temperatures by optimizing basal heat-flow density and ignoring sediment heat production, the extrapolated present-day temperature of a deeply buried source rock would be overestimated.Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we

  14. New insights into Phanerozoic tectonics of south China: Part 1, polyphase deformation in the Jiuling and Lianyunshan domains of the central Jiangnan Orogen

    Science.gov (United States)

    Li, Jianhua; Dong, Shuwen; Zhang, Yueqiao; Zhao, Guochun; Johnston, Stephen T.; Cui, Jianjun; Xin, Yujia

    2016-04-01

    The central Jiangnan Orogen, genetically formed by the Proterozoic Yangtze-Cathaysia collision, presents as a composite structural feature in the Phanerozoic with multiple ductile and brittle fabrics whose geometries, kinematics, and ages are crucial to decipher the tectonic evolution of south China. New structural observations coupled with thermochronological and geochronological studies of these fabrics document four main stages of deformation. The earliest stage in early Paleozoic time (460-420 Ma) corresponds to combined E-trending dextral and northwest directed thrust shearing that was variably partitioned in anastomosing high-strain zones under greenschist-facies conditions (~400-500°C), related to the continued Yangtze-Cathaysia convergence externally driven by the suturing of south China with Australia. This event was heterogeneously overprinted by the second stage characterized by ~E-oriented folding in middle Triassic time, geodynamically resulting from the continental collision of south China with Indochina and North China. The third stage was locally developed by northwest and southeast vergent thrusts that truncated ~E-oriented folds in the Late Jurassic, due to northwestward subduction of the Paleo-Pacific plate. The latest stage involved normal faulting and tectonic unroofing in Cretaceous time, which resulted in basin opening and reset footwall 40Ar/39Ar ages in proximity to the Hengshan detachment fault, associated with roll-back of the subducting Paleo-Pacific plate.

  15. Cambrian Ichnofossils from the Zhoujieshan Formation (Quanji Group) Overlying Tillites in the Northern Margin of the Qaidam Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    Yue Wang; Xunlian Wang; Ye Wang

    2015-01-01

    The Quanji Group is composed of siliciclastics and carbonates and was deposited on a relatively stable block, in the northern margin of the Qaidam Basin, NW China. It is one of the research hotspots in the Qilian-Qinling-Kunlun tectonic zones. However, it has long been argued whether the up-per Quanji Group should be assigned to the Precambrian or the Cambrian for lack of convincing fossil evidence. The discovery of ichnofossils, including Rusophycus, Cruziana, Dimorphichnus, Treptichnus, Skolithos, Arenicolites, Palaeophycus, and Helminthopsis, indicates that the upper member of the Zhou-jieshan Formation (top Quanji Group) is Cambrian in age, and at least above the Treptichnus (Phycodes) pedum Biozone, the lowermost biozone in the Cambrian. The lower member of the Zhoujieshan Forma-tion should belong to the Cambrian. During the time when the upper member of the Zhoujieshan For-mation was deposited, the northern margin of the Qaidam Basin was dominated by the Cruziana Ichno-facies, characterizing a lower-energy shelf (shallow) sea environment with moderate-rich oxygen con-tents. In addition, the conglomerates in the Hongtiegou Formation of the Quanji Group underlying the Zhoujieshan Formation were generally regarded as tillites. However, the dolostones of the lower member of the Zhoujieshan Formation are, in lithology and geochemistry, different from the typical cap-dolostones of the Doushantuo Formation in South China, so it is necessary to further study the ori-gins of the lower member of the Zhoujieshan Formation and the conglomerates of the Hongtiegou For-mation.

  16. Nonstationarity in the occurrence rate of floods in the Tarim River basin, China, and related impacts of climate indices

    Science.gov (United States)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Chen, Xi; Liu, Lin

    2016-07-01

    Amplification of floods in the Xinjiang, China, has been observed, but reports on their changing properties and underlying mechanisms are not available. In this study, occurrence rates of floods in the Tarim River basin, the largest inland arid river basin in China, were analyzed using the Kernel density estimation technique and bootstrap resampling method. Also analyzed were the occurrence rates of precipitation extremes using the POT (Peak over Threshold)-based sampling method. Both stationary and non-stationary models were developed using GAMLSS (Generalized Additive Models for Location, Scale and Shape) to model flood frequency with time, climate index, precipitation and temperature as major predictors. Results indicated: (1) two periods with increasing occurrence of floods, i.e., the late 1960s and the late 1990s with considerable fluctuations around 2-3 flood events during time intervals between the late 1960s and the late 1990s; (2) changes in the occurrence rates of floods were subject to nonstationarity. A persistent increase of flood frequency and magnitude was observed during the 1990s and reached a peak value; (3) AMO (Atlantic Multidecadal Oscillation) and AO (Atlantic Oscillation) in winter were the key influencing climate indices impacting the occurrence rates of floods. However, NAO (North Atlantic Oscillation) and SOI (South Oscillation Index) are two principle factors that influence the occurrence rates of regional floods. The AIC (Akaike Information Criterion) values indicated that compared to the influence of climate indices, occurrence rates of floods seemed to be more sensitive to temperature and precipitation changes. Results of this study are important for flood management and development of mitigation measures.

  17. Research on environmental flow in Huai River Basin, China

    Science.gov (United States)

    Liu, H. C.; Shui, Y.; Li, L. H.; Cao, N.; Yu, G. Y.; Liu, J.

    2016-08-01

    The estimation methods for environmental flow were discussed in this paper. Based on the comparative analysis of calculation methods of environmental flow, a "Huaihe Method" was proposed, which consists of the hydrological estimation of the minimum environmental flow with validation by the requirment space for fish. The minimum environmental flows of the important control sections in main stream and tributaries in the Huai River basin are estimated. The recommened minimum environmental flow has been adopted in the water resources planning, which provided reference for rational allocation of environmental flow, water resources usage, and sustainable development for the local society.

  18. Hydrocarbon Migration and Accumulation in Dongying Basin

    Institute of Scientific and Technical Information of China (English)

    Li Chunguang; Shang Weirong

    1996-01-01

    @@ Dongying basin is a faulted basin rich in hydrocarbon and is under more exploration (wildcat well density is 0.155 well/km ) in the southern Bohai Bay area of China, covering an area of 5700 km. Based on the paleotopographic setting of Paleozoic basement rocks, the basin was evolved into Mesozoic and Cenozoic basin which was faulted in the north and overlapped in the south by the blockfaulting movement in J2-J3. So, each formation of the source rocks in Paleogene is characterized by thick deposit in the north and thin deposit in the south.

  19. Possible Future Climate Change Impacts on the Hydrological Drought Events in the Weihe River Basin, China

    OpenAIRE

    Fei Yuan; Mingwei Ma; Liliang Ren; Hongren Shen; Yue Li; Shanhu Jiang; Xiaoli Yang; Chongxu Zhao; Hao Kong

    2016-01-01

    Quantitative evaluation of future climate change impacts on hydrological drought characteristics is one of important measures for implementing sustainable water resources management and effective disaster mitigation in drought-prone regions under the changing environment. In this study, a modeling system for projecting the potential future climate change impacts on hydrological droughts in the Weihe River basin (WRB) in North China is presented. This system consists of a large-scale hydrologi...

  20. Assessment of River Habitat Quality in the Hai River Basin, Northern China

    OpenAIRE

    Yuekui Ding; Baoqing Shan; Yu Zhao

    2015-01-01

    We applied a river habitat quality (RHQ) assessment method to the Hai River Basin (HRB); an important economic centre in China; to obtain baseline information for water quality improvement; river rehabilitation; and watershed management. The results of the assessment showed that the river habitat in the HRB is seriously degraded. Specifically; 42.41% of the sites; accounting for a river length of 3.31 × 104 km; were designated poor and bad. Habitat in the plain areas is seriously deteriorated...

  1. Network Analysis for a Better Water Use Configuration in the Baiyangdian Basin, China

    OpenAIRE

    Xufeng Mao; Donghai Yuan; Xiaoyan Wei; Qiong Chen; Chenling Yan; Liansheng He

    2015-01-01

    Nowadays, an increasing shortage of water resources intensifies the contradiction among different water-using sectors in the social-economic-ecological complex system. To adjust water used configuration in a holistic framework, a water use system (WUS) model was constructed with inclusive five water-using sectors including aquatic systems, primary industry, secondary industry, tertiary industry and resident consumption. The Baiyangdian Basin in Northern China was used as a case area. Six yea...

  2. Odonata diversity of the middle and lower reaches of the Red River basin, Yunnan, China

    Directory of Open Access Journals (Sweden)

    Jin Chen

    2013-09-01

    Full Text Available Eighty six species of Odonata are recorded from the middle and lower reaches of the Red River basin. Archineura hetaerinoides is recorded from China for the first time. Five genera and five species are new to Yunnan Province. Among the six types of odonate habitats, forest streams have the highest species diversity whereas ponds have the most species shared with other habitats. Both of these two habitats are important in biodiversity conservation and need urgent protection.

  3. Formation and Identification of Unresolved Complex Mixtures in Lacustrine Biodegraded Oil from Nanxiang Basin, China

    OpenAIRE

    Pengfei Guo; Sheng He; Shukui Zhu; Derong Chai; Shiyan Yin; Wei Dai; Wanfeng Zhang

    2014-01-01

    A comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS) method has been developed for the formation and identification of unresolved complex mixtures (UCMs) in lacustrine biodegraded oils that with the same source rock, similar maturity, and increasing degradation rank from Nanxiang Basin, China. Normal alkanes, light hydrocarbons, isoprenoids, steranes, and terpanes are degraded gradually from oil B330 to oil G574. The compounds in biodegraded oil ...

  4. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    OpenAIRE

    Pan Chen; Lan Li; Hongbin Zhang

    2015-01-01

    Understanding the spatio-temporal variation and the potential source of water pollution could greatly improve our knowledge of human impacts on the environment. In this work, data of 11 water quality indices were collected during 2012–2014 at 10 monitoring sites in the mainstream and major tributaries of the Danjiangkou Reservoir Basin, Central China. The fuzzy comprehensive assessment (FCA), the cluster analysis (CA) and the discriminant analysis (DA) were used to assess the water pollutio...

  5. Measurements of energy and water vapor fluxes over different surfaces in the Heihe River Basin, China

    OpenAIRE

    Liu, S.; Xu, Z.; Wang, W.; J. Bai; Jia, Z; Zhu, M.; Wang, J.

    2010-01-01

    We analyzed the seasonal variations of energy and water vapor fluxes over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy and water vapor fluxes were measured using eddy covariance systems (EC) and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site, and discussed th...

  6. SPATIAL AND TEMPORAL VARIATIONS OF EVAPORATION OVER SOUTH CHINA IN AUTUMN

    Institute of Scientific and Technical Information of China (English)

    XIAO Wei-jun; LIANG Yu-qiong; HE Ju-xiong; CHEN Bing-hong

    2008-01-01

    The spatial and temporal variations of the instrument-based evaporation and actual evaporation in autumn during a 45-year period fi'om 1960 to 2004 are studied using the observation data from 66 stations over South China. The results reveal that there are two main anomalous centers of the instrument-based evaporation in autumn in the central and northwestern parts of South China respectively. The instrument-based evaporation over the central part of South China in autumn experiences not only a decreasing trend but also a main interdecadal variation. The solar radiation is best correlated with the instrument-based evaporation among all affecting factors. For the actual evaporation, two main anomalous centers are located at the central and western parts of the South China respectively. The actual evaporation over the two regions illustrates an interannual variation. Among the affecting factors, precipitation is the most remarkable. The actual evaporation is usually 40 percent of the instrument-based one, and the overall rate has a slightly increasing trend from the southern part to the northern part of the South China in autumn.

  7. Critical role of meteorological conditions in a persistent haze episode in the Guanzhong basin, China.

    Science.gov (United States)

    Bei, Naifang; Xiao, Bo; Meng, Ning; Feng, Tian

    2016-04-15

    In the present study, the critical role of the meteorological condition in a persistent extreme haze episode that occurred in Guanzhong basin of China on December 16 to 25, 2013 has been investigated. Analyses of the large-scale meteorological conditions on 850hPa during the episode have been performed using the NCEP FNL data set, indicating that synoptic situations generally facilitate the accumulation of pollutants either in horizontal or vertical directions in the basin. The FLEXPART model has been utilized to illustrate the pollutant transport patterns during the episode, further showing the dominant role of synoptic conditions in accumulation of pollutants in the basin. Detailed meteorological conditions, such as temperature inversion, and low-level horizontal wind speed also contribute to the extreme haze episode. In addition, the WRF-CHEM model has been used to evaluate the responses of the surface PM2.5 level to the emission mitigation. Generally, the predicted PM2.5 spatial patterns and temporal variations agree well with the observations at the ambient monitoring sites. Sensitivity studies show that the emissions in the basin need to be mitigated by more than 91% to meet the excellent level of the China National Air Quality Standard under the extremely unfavorable meteorological conditions, demonstrating that it is imperative to implement stringent controls on emissions to improve the air quality.

  8. Assessment of spatial and temporal patterns of green and blue water flows in inland river basins in Northwest China

    Directory of Open Access Journals (Sweden)

    C. F. Zang

    2012-03-01

    Full Text Available In arid and semi-arid regions freshwater resources have become scarcer with increasing demands from socio-economic development and population growth. Until recently, water research and management in these has mainly focused on blue water but ignored green water. Here we report on spatial and temporal patterns of both blue and green water flows simulated by the Soil and Water Assessment Tool (SWAT for the Heihe river basin, the second largest inland river basin in Northwest China. Calibration and validation at two hydrological stations show good performance of the SWAT model in modelling hydrological processes. The total green and blue water flows were 22.09 billion m3 in the 2000s for the Heihe river basin. Blue water flows are larger in upstream sub-basins than in downstream sub-basins mainly due to high precipitation and large areas of glaciers in upstream. Green water flows are distributed more homogeneously among different sub-basins. The green water coefficient was 88.0% in the 2000s for the entire river basin, varying from around 80–90% in up- and mid-stream sub-basins to above 95% in downstream sub-basins. This is much higher than reported green water coefficient in many other river basins. The spatial patterns of green water coefficient were closely linked to dominant land covers (e.g. glaciers in upstream and desert in downstream and climate conditions (e.g. high precipitation in upstream and low precipitation in downstream. There are no clear consistent historical trends of change in green and blue water flows and green water coefficient at both the river basin and sub-basin levels. This study provides insights into green and blue water endowments for the entire Heihe river basin at sub-basin level. The results are helpful for formulating reasonable water policies to improve water resources management in the inland river basins of China.

  9. Water Masses in the South China Sea and Water Exchange between the Pacific and the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LI Fengqi; LI Lei; WANG Xiuqin; LIU Changle

    2002-01-01

    Water masses in the South China Sea (SCS) were identified and analyzed with the data collected in the summer and winter of 1998. The distributions of temperature and salinity near the Bashi Channel (the Luzon Strait) were analyzed by using the data obtained in July and December of 1997. Based on the results from the data collected in the winter of 1998,waters in the open sea areas of the SCS were divided into six water masses: the Surface Water Mass of the SCS (S), the Subsurface Water Mass of the SCS (U), the Subsurface-Intermediate Water Mass of the SCS (UI), the Intermediate Water Mass of the SCS (I), the Deep Water Mass of the SCS (D) and the Bottom Water Mass of the SCS(B). For the summer of 1998,the Kuroshio Surface Water Mass (KS) and the Kuroshio Subsurface Water Mass (KU) were also identified in the SCS. But no Kuroshio water was found to pass the 119.5°E meridian and enter the SCS in the time of winter observations. The Sulu Sea Water (SSW) intruded into the SCS through the Mindoro Channel between 50-75 m in the summer of 1998. However, the data obtained in the summer and winter of 1997 indicated that water from the Pacific had entered the SCS through the northern part of the Luzon Strait in these seasons, but water from the SCS had entered the Pacific through the southern part of the Strait. These phenomena might correlate with the 1998 El-Nino event.

  10. Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

    Science.gov (United States)

    Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

    2015-04-01

    The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary

  11. Comparison of modern pollen distribution between the northern and southern parts of the South China Sea

    Science.gov (United States)

    Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

    2015-04-01

    The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

  12. Drought Trends and Temperature Influence in Zhanghe River Basin, China

    OpenAIRE

    Bakhtawar Wagan; Zhanyu Zhang; Feng Baoping; Si Han; Kabo-bah, Amos T.

    2015-01-01

    Our study area is one of the semiarid region of the China with under water stress condition that causes economic damage. The main objective of this study is to apply standardized precipitation evapotranspiration index (SPEI) and to use linear regression to calculate drought conditions in the study area. For this purpose, data from 1980 to 2010 was analyzed at different (1, 6, 12, and 24 months) time scales. Results depicted both dry and wet periods in the study area; occurrence of dry span wi...

  13. Magnetostratigraphic dating of mammalian fossils in Junggar Basin, northwest China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui; YUE LePing; WANG JianQi

    2007-01-01

    The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented, based on rock magnetic experiments and magnetostratigraphic investigations of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization, and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS).Furthermore, the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary, and the Suosuoquan fauna layer is just above the Neocene onset. Therefore, the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma, respectively.

  14. Pressure Prediction for High-Temperature and High-Pressure Formation and Its Application to Drilling in the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; XIE Xinong

    2004-01-01

    There are plentiful potential hydrocarbon resources in the Yinggehai and Qiongdongnan basins in the northern South China Sea. However, the special petrol-geological condition with high formation temperature and pressure greatly blocked hydrocarbon exploration. The conventional means of drills, including methods in the prediction and monitoring of underground strata pressure, can no longer meet the requirements in this area. The China National Offshore Oil Corporation has allocated one well with a designed depth of 3200 m and pressure coefficient of 2.3 in the Yinggehai Basin (called test well in the paper) in order to find gas reservoirs in middle-deep section in the Miocene Huangliu and analyzed the distribution of overpressure in the Yinggehai and Qiongdongnan basins, and set up a series of key technologies and methods to predict and monitor formation pressure, and then apply the results to pressure prediction of the test well. Because of the exact pressure prediction before and during drilling, associated procedure design of casing and their allocation in test well has been ensured to be more rational. This well is successfully drilled to the depth of 3485 m (nearly 300 m deeper than the designed depth) under the formation pressure about 2.3 SG (EMW), which indicate that a new step in the technology of drilling in higher temperature and pressure has been reached in the China National Offshore Oil Corporation.

  15. A Preliminary Study of the Gas Hydrate Stability Zone in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    金春爽; 汪集旸

    2002-01-01

    Based on the analysis of sea-bottom temperature and geothermal gradient, and by means of the phaseboundary curve of gas hydrate and the sea-bottom temperature versus water depth curve in the South China Sea, thispaper studies the temperature and pressure conditions for gas hydrate to keep stable. In a marine environment, methanehydrate keeps stable at water depths greater than 550 m in the South China Sea. Further, the thickness of the gas hydratestability zone in the South China Sea was calculated by using the phase boundary curve and temperature-depth equations.The result shows that gas hydrate have a better perspective in the southeast of the Dongsha Islands, the northeast of theXisha Islands and the north of the Nansha Islands for thicker stability zones.

  16. Characteristics and Tectonic Significance of the Gravity Field in South China

    Institute of Scientific and Technical Information of China (English)

    YAN Yafen; WANG Guangjie; ZHANG Zhongjie

    2004-01-01

    Based on gravity data processed with the matched filter, depth continuation and horizontal gradient we obtained the spatial distribution of the gravity field and made analyses of the tectonic framework of South China. Then, inversion was conducted for the depth to study the depth variation of the boundary between the crust and upper mantle, namely the Mohorovicic discontinuity (Moho). The results demonstrate that the Moho depth in South China ranges from 30 to 40 km, and the crust thins from west to east, 27-29 km under the continent margin and shallow sea. We think it possible that the Tanlu fault crosses the Yangtze River and extends southwards along the Ganjiang and Wuchuan-Sihui faults to the South China Sea, and that there is an EW hidden structural belt along 24.5°-26°.

  17. Data from renewable energy assessments for resort islands in the South China Sea

    Directory of Open Access Journals (Sweden)

    M. Reyasudin Basir Khan

    2016-03-01

    Full Text Available Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015 [1].

  18. Data from renewable energy assessments for resort islands in the South China Sea.

    Science.gov (United States)

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article "Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea" published in Energy (Khan et al., 2015) [1].

  19. Measurement of single-fish target strength in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    CHEN Guobao; LI Yongzhen; CHEN Pimao; ZHANG Jun; FANG Lichen; LI Nana

    2012-01-01

    We measured the target strength (TS) of three commercial fish species:whitespotted spinefoot (Siganus canaliculatus),black porgy (Acanthopagrus schlegelii),and creek red bream (Lutjanus argentimaculatus),in the South China Sea.The TS of caged or tethered fish (n=76 total) was measured using a Simrad EY60 portable scientific echosounder at 120 kHz.We evaluated the relationship between TS and total length (TL,cm) for the three species.This is the first attempt to use split-beam acoustics to measure single-fish TS in the South China Sea by Chinese researchers.Our results will improve the accuracy and precision of acoustic abundance estimates of commercially important species and further the development of underwater acoustic survey techniques in fisheries in the South China Sea.

  20. The barrier layer in the southern region of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By analysing the CTD data in the southernregion of the South China Sea gathered during six cruises between 1989 and 1999, a barrier layer with seasonal variation just like what exists in the equatorial oceans is found in this region. It is the first discovery in such a marginal sea yet.It is strong in autunm and a little weak in summer and winter. The thicker the barrier layer, the higher the average temperature of the upper mixed layer. The region with the thicker barrier layer overlaps the region with the higher average temperature of the upper mixed layer, and accords with the thicker region of the warm pool in the South China Sea got from the Levitus data. The barrier layer in the southern region of the South China Sea has significant influence on the heat storage of the upper ocean there.``

  1. Energy audit data for a resort island in the South China Sea.

    Science.gov (United States)

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article "Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea" [1].

  2. Historical Introduction of Japanese Wild Mice, Mus musculus, from South China and the Korean Peninsula

    Directory of Open Access Journals (Sweden)

    Mitsuo Nunome

    2013-10-01

    Full Text Available In Japan, the wild house mouse Mus musculus consists of two lineages, one from Southeast Asia (Mus musculus castaneus; CAS and one from northern Eurasia (Mus musculus musculus; MUS. However, the exact origins of the parental lineages are unclear. A recent work using mitochondrial sequences revealed that Japanese CAS and MUS are closely related to haplotypes from South China and the Korean Peninsula, respectively. Recent phylogeographic analyses using nuclear gene sequences have also confirmed a close relationship between Japan and Korea in the MUS component. However, the Japanese CAS components in the nuclear genome are likely to be unique and to differ from those of other CAS territories, including South China. Although the origins are still unresolved, these results allow us to conclude that two areas of the continent, South China and the Korean Peninsula, are the primary source areas of Japanese wild mice and suggest pre-historical introductions associated with certain historical agricultural developments in East Asia.

  3. Soil erosion assessment based on minimum polygons in the Yellow River basin, China

    Science.gov (United States)

    Ni, Jin-Ren; Li, Xiu-Xia; Borthwick, A. G. L.

    2008-01-01

    In the previous studies, a method was developed to assess soil erosion based on land use information. In this paper, we present another approach that uses environmental data to assess soil erosion. A soil erosion characteristic index EI is proposed, and its value is derived using the Analytic Hierarchy Process (AHP) technique based on standardized environmental information stored in minimum polygons that tile the erodible area under consideration. The approach is applied to a case study of the Yellow River basin, north China, where serious erosion is occurring. To represent different grades of soil erosion, the range of EI is divided into six levels according to standard grades of soil erosion intensity. The application indicates that the method deals properly with data scarcity, with the results giving a satisfactory representation of the characteristics of soil erosion in the Yellow River basin. The spatial-temporal distribution of EI in the Yellow River basin is predicted, and the results interpreted to give the long-term trend and state of soil depletion. Comparisons are given between EI and surveyed soil erosion zoning maps for the Yellow River basin at the end of the 1980s and 1990s. The output reliability and the approach applicability in smaller spatial scales are investigated in a case study of Zhifanggou basin.

  4. Desertification and Sustainable Development of the Heihe River Basin in Arid Northwestern China

    Institute of Scientific and Technical Information of China (English)

    Qi Shanzhong; Luo Fang

    2004-01-01

    The Heihe River Basin of northwestern China is one of several areas severely affected by desertification. This article outlines the status of desertification in this basin. There are mainly 5 types of desertification in the Heihe River Basin, namely soil and water erosion, sandy desertification, soil aridization, soil salinization and vegetation degradation.Among the 5 types of desertification, the main desertification type is sandy desertification with an area of 10 771.97 km2; Second type is soil salinization with an area of 10 591.82 km2; Next to the soil salinization is the type of soil and water erosion with an area of 5 747.68 km2 and the other types of desertification in the Heihe River Basin are soil aridization with just area of 1 369.96 km2 and vegetation degradation type with an area of 1 490.48km2 respectively. Both natural and man-made factors are responsible for the causes of desertification development, among which the latter is the main driving force for desertification in the basin.

  5. Palaeoclimatic evolution during Eocene and its influence on oil shale mineralisation, Fushun basin, China

    Science.gov (United States)

    Meng, Qingtao; Liu, Zhaojun; Bruch, Angela A.; Liu, Rong; Hu, Fei

    2012-02-01

    The Fushun basin is a small, explored, coal and oil shale-bearing, Cenozoic fault basin in the Liaoning Province, northeast China. The basin mainly consists of Eocene swamp to lacustrine deposits of the Guchengzi to Xilutian Formation, and contains the biggest opencast oil shale mine in Asia. This mine has provided an ideal opportunity to undertake palaeoclimate reconstruction in this basin based on a single geological profile and the analyses of 93 samples, using various approaches, namely field geological observation, clay mineralogical and geochemical (Sr/Ba, Sr/Cu, stable C and O isotope) analyses, all of which were compared with palaeobotanical data. The Eocene climate of Fushun basin evolved from warm temperate to north subtropical, and generally changed from warm humid to subhumid-semiarid. Paleoclimatic and geochemical parameters shows that the very warm and humid climate during Jijuntun Formation increased the initial productivity of lake water, and caused a steady stratification of the lake water, then ca