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Sample records for basin nw china

  1. Carbonate reservoirs modified by magmatic intrusions in the Bachu area, Tarim Basin, NW China

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    Kang Xu

    2015-09-01

    Full Text Available Oil and gas exploration in carbonate rocks was extremely successful in recent years in the Ordovician in Tarim Basin, NW China. Here, we investigate the carbonate reservoirs in the Bachu area of the Tarim Basin through petrological and geochemical studies combined with oil and gas exploration data. Geochemical analysis included the major, trace, and rare earth elements; fluid inclusion thermometry; clay mineral characterization; and carbon and oxygen isotopes of the carbonate rocks. Homogenization temperatures of the fluid inclusions of Well He-3 in the Bachu area indicate three groups, 60–80 °C, 90–130 °C, and 140–170 °C, and suggest that the carbonate rocks experienced modification due to heating events. The porosity in the reservoir is defined by fractures and secondary pores, and there is a notable increase in the porosity of the carbonate reservoirs in proximity to magmatic intrusion, particularly approximately 8–10 m from the intrusive rocks. The development of secondary pores was controlled by lithofacies and corrosion by various fluids. We identify supercritical fluids with high density (138.12–143.97 mg/cm3 in the Bachu area. The negative correlations of δ13C (−2.76‰ to −0.97‰ and δ18O (−7.91‰ to −5.07‰ suggest that the carbonate rocks in the study area were modified by high-salinity hydrothermal fluid. The formation of clay minerals, such as illite and montmorillonite, caused a decrease in porosity. Our study demonstrates the effect of magmatic intrusions in modifying the reservoir characteristics of carbonate rocks and has important implications for oil and gas exploration.

  2. Iron speciation and mineral characterization of upper Jurassic reservoir rocks in the Minhe Basin, NW China

    Science.gov (United States)

    Ma, Xiangxian; Zheng, Guodong; Xu, Wang; Liang, Minliang; Fan, Qiaohui; Wu, Yingzhong; Ye, Conglin; Shozugawa, Katsumi; Matsuo, Motoyuki

    2016-12-01

    Six samples from a natural outcrop of reservoir rocks with oil seepage and two control samples from surrounding area in the Minhe Basin, northwestern China were selectively collected and analyzed for mineralogical composition as well as iron speciation using X-ray powder diffraction (XRD) and Mössbauer spectroscopy, respectively. Iron species revealed that: (1) the oil-bearing reservoir rocks were changed by water-rock-oil interactions; (2) even in the same site, there was a different performance between sandstone and mudstone during the oil and gas infusion to the reservoirs; and (3) this was evidence indicating the selective channels of hydrocarbon migration. In addition, these studies showed that the iron speciation by Mössbauer spectroscopy could be useful for the study of oil and gas reservoirs, especially the processes of the water-rock interactions within petroleum reservoirs.

  3. The quantitative reconstruction of the palaeoclimate between 5200 and 4300 cal yr BP in the Tianshui Basin, NW China

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    N. Sun

    2012-03-01

    Full Text Available The quantitative reconstruction of the palaeoclimate is a prerequisite for understanding climate processes at time scales of centuries and millennia. Here, the coexistence approach (CA was applied to reconstruct climatic factors quantitatively based on the fossil charcoal records between 5200 and 4300 cal yr BP in the Tianshui Basin, NW China. The CA analysis showed that the climate of the Tianshui Basin belonged to the northern subtropical zone between 5200 and 4300 cal yr BP. The mean annual temperature (MAT was approximately 13.2 °C, and the mean annual precipitation (MAP was approximately 778 mm between 5200 and 4900 cal yr BP. The MAT was approximately 13.2 °C, and the MAP was approximately 688 mm between 4800 and 4300 cal yr BP. The MAT was approximately 2.2 °C higher than today, and the MAP was approximately 280 mm higher than today from 5200 to 4900 cal yr BP. The MAT was also approximately 2.2 °C higher than today from 4800 to 4300 cal yr BP, while the MAP was approximately 196 mm higher than today. No abrupt cold event occurred between 5200 and 4300 cal yr BP; however, a drought tendency appeared after around 4800 cal yr BP.

  4. Formation mechanism of carbonate cemented zones adjacent to the top overpressured surface in the central Junggar Basin,NW China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin,NW China.Stable carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that:(1) carbonate cements are composed dominantly of ferrocalcite,ferroan dolomite,and ankerite;(2) carbonate cements are formed under a high temperature circumstance in the subsurface,and organic fluid migration has an important effect on the formation of them;and(3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured system.This suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological time.This study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins,and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

  5. 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.

  6. Zircon U-Pb SHRIMP Ages from the Late Paleozoic Turpan-Hami Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    Xiang Mao; Jianghai Li; Huatian Zhang

    2014-01-01

    Permian volcanic rocks are widely distributed in the Turpan-Hami Basin, which is part of the Central Asian orogenic belt. Here we present SHRIMP zircon data for the rhyolite in Well Baocan 1, one of the deepest wells in the basin. The 283.9±2.7 Ma reported in our study provides the best precise age determination for the Yierxitu Formation, the oldest Permian layer of Hami Depression, one of the three substructural units of the Turpan-Hami Basin, and a potential hydrocarbon reservoir in this ba-sin. Our data refines earlier imprecise39Ar-40Ar ages and shows that the volcanic rocks both inside the Turpan-Hami Basin and along its margin are almost coeval. We delineate a collisional orogenesis, and the new age of 283.9±2.7 Ma may limit the latest time of the collision orogenesis.

  7. Petroleum migration and mixing in the northwestern Junggar Basin (NW China): constraints from oil-bearing fluid inclusion analyses

    Energy Technology Data Exchange (ETDEWEB)

    Jian Cao; Suping Yao [Nanjing University (China). Dept. of Earth Sciences; Zhijun Jin [Exploration and Production Research Institute, Beijing (CN)] (and others)

    2006-07-15

    Abundant oil-bearing fluid inclusions are present in four reservoir sandstone samples from the slope and fault zone areas in the northwestern margin of the Junggar Basin (NW China). Free oil in intergranular pores, adsorbed oil on grain surfaces, and petroleum in inclusions hosted by mineral grains of these samples were analyzed by gas chromatography and gas chromatography-mass spectrometry. Analytical results indicate similar biomarker distributions in the three bitumen fractions of the samples collected from the slope area, which correlate well with characteristic of the source rocks in the Lower Permian Fengcheng Formation. This is in contrast to the fault zone, where the three bitumen fractions vary significantly in their geochemical signatures, suggesting that all of the three Permian source sequences rocks (including the Lower Permian Jiamuhe and Fengcheng formations, and the Middle Permian Lower Wuerhe Formation) have been mature and contributed to the oils in the fault zone. The presence of an unresolved hydrocarbon hump and a full range of unaltered n-alkanes in the gas chromatograms of samples collected from the fault zone indicate an earlier hydrocarbon biodegradation and subsequent injection of fresh oils, distinctly different from that in the slope area. Petrographic and microthermometric investigations of oil-bearing fluid inclusions suggest a single oil charge in the slope area (to the Lower Triassic reservoir, occurring during the Late Triassic to Early Jurassic time). In the fault zone, oil migration and mixing took place mainly during the Late Triassic to Early Jurassic and Cretaceous, followed by gas migration in the Tertiary period. The different petroleum migration and mixing histories in the slope and fault zones are attributed to the effect of fault-controlled oil and gas migration. (author)

  8. Analysis on Structural Control of Coal Distribution in the Northern Qaidam Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    LIU Tianji; WANG Tong; ZHAN Wenfeng

    2008-01-01

    The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.

  9. Analysis on structural control of coal distribution in the northern Qaidam Basin, NW China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.J.; Wang, T.; Zhan, W.F. [Qinghai Bureau of Coal Geology, Xining (China)

    2008-06-15

    The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.

  10. Molecular fossils and oil-source rock correlations in Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The distribution of "molecular fossils" (biomarkers) of steroid compounds in extracts from some specific geologic age in the Tarim Basin have been analyzed and are used as the fingerprints for the oil-source rock correlation. Having been affected by maturation, migration, phase fractionation and biodegradation, not any molecular fossils related to source and environment can be used as the fingerprints for oil-source rock correlation. Some special biomarkers widely existed in the extracts from Cambrian and Ordovician rocks in the Tarim Basin and showed obvious difference in each stratum, including dinosteranes (C30), 4-methyl-24-ethyl-cholestanes (C30) and their aromatized steroids, C24-norcholestanes and C28 steranes originated from dinoflagellates and diatom. Few oils such as the heavy oil drilled in the Cambrian reservoir from Tadong 2 well (TD2) correlated well with the extracts from the Cambrian. The amazing similarity of the relative contents of these compounds between the marine oils produced in Tazhong and Tabei uplifts and the extracts from the Upper Ordovician suggests that the Middle-Upper Ordovician is the very likely main source for the marine oils.

  11. Palaeo-earthquake events during the late Early Palaeozoic in the central Tarim Basin (NW China: evidence from deep drilling cores

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    He Bizhu

    2014-07-01

    Full Text Available Various millimetre-, centimetre- and metre-scale soft-sediment deformation structures (SSDS have been identified in the Upper Ordovician and Lower-Middle Silurian from deep drilling cores in the Tarim Basin (NW China. These structures include liquefied-sand veins, liquefaction-induced breccias, boudinage-like structures, load and diapir- or flame-like structures, dish and mixed-layer structures, hydroplastic convolutions and seismic unconformities. The deformed layers are intercalated by undeformed layers of varying thicknesses that are petrologically and sedimentologically similar to the deformed layers.

  12. The Formation and Distribution of the Marine Hydrocarbon Source Rock in the Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    CAI Xiyuan; WANG Yi

    2008-01-01

    There are significant differences in type and distribution between marine source rock and continental source rock. According to the lithology, the Cambrian-Ordovician source rock in the Tarim basin is divided into two types: the carbonate source rock and the mud source rock. The two sets of source rocks are developed mainly in three sets of formations, Lower-Middle Cambrian carbonate source rock and mud source rock, Lower-Middle Ordovician mud source rock and Upper Ordovician lime mud source rock. The stratigraphic and areal distributions of the source rocks are controlled by the altitude and the sedimentary facies respectively. The mud source rock is developed in slope-semi deep sea environment. The source rock developed in the slope sedimentary environment is related with the anoxic environment and the one developed in semi deep sea has a close relationship with the up-flowing sea water. The carbonate source rock is developed mainly in platform slope of highstand systems tract and it is usually intimately associated with the salt rock. The Lower-Middle Cambrian carbonate source rock is developed mainly in the Bachu, Tazhong, Taugguzibasi and Yingmaili areas. The Lower-Middle Cambrian mud source rock is mainly developed in the areas east of the line of Kunan 1-Tadong 1. The Lower-Middle Ordovician mud source rock is developed mainly in the east slope of the Manjiaer depression. The carbonate source rock of Early Ordovician is developed mainly in the platform slope of highstand systems tract, such as the south margin of Tabei, the north slope of Tazhong, the Bachu area and Keping area.

  13. Assessment of the hydrogeochemistry and groundwater quality of the Tarim River Basin in an extreme arid region, NW China.

    Science.gov (United States)

    Xiao, Jun; Jin, Zhangdong; Wang, Jin

    2014-01-01

    The concentrations of the major and trace elements in the groundwater of the Tarim River Basin (TRB), the largest inland river basin of China, were analyzed before and during rainy seasons to determine the hydrogeochemistry and to assess the groundwater quality for irrigation and drinking purposes. The groundwater within the TRB was slightly alkaline and characterized by high ionic concentrations. The groundwater in the northern sub-basin was fresh water with a Ca(2+)-HCO3(-) water type, whereas the groundwater in the southern and central sub-basins was brackish with a Na(+)-Cl(-) water type. Evaporite dissolution and carbonate weathering were the primary and secondary sources of solutes in the groundwater within the basin, whereas silicate weathering played a minor role. The sodium adsorption ratio (SAR), water quality index (WQI), and sodium percentage (%Na) indicated that the groundwater in the northern sub-basin was suitable for irrigation and drinking, but that in the southern and central sub-basins was not suitable. The groundwater quality was slightly better in the wet season than in the dry season. The groundwater could be used for drinking after treatment for B(3+), F(-), and SO4(2-) and for irrigation after control of the sodium and salinity hazards. Considering the high corrosivity ratio of the groundwater in this area, noncorrosive pipes should be used for the groundwater supply. For sustainable development, integrated management of the surface water and the groundwater is needed in the future.

  14. Stable isotope (δ13Cker, δ13Ccarb, δ18Ocarb distribution along a Cambrian outcrop section in the eastern Tarim Basin, NW China and its geochemical significance

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    Hu Liu

    2017-01-01

    Full Text Available This study investigated the geochemical features of the lower Paleozoic strata of Yaerdang Mountain outcrop along with the core samples from well TD2∈ in the eastern Tarim Basin, NW China. The total organic carbon abundance, hydrocarbon-generating precursor biospecies, and stable isotope ratios of organics and carbonate (δ13Cker, δ13Ccarb and δ18Ocarb were comprehensively studied for their possible correlative constraints during sedimentary evolution. The results revealed that the δ13Cker (VPDB of Cambrian kerogens along the outcrop section varied from −34.6‰ to −28.4‰, indicating an increasing tendency from the lower Cambrian to the upper Cambrian. This was on the whole accompanied by the variation in the δ13Ccarb and δ18Ocarb along the profile, which might be associated with the changes in the sea level and also in the compositional variation of benthic and planktonic biomass. The large variation in the stable carbon isotope ratios up to 6‰ along the outcrop section reflected the heterogeneity of the Cambrian source rocks from the eastern Tarim Basin. Hence, the 13C-enriched crude oils from well TD2∈ might have been derived from a localized stratum of Cambrian source rocks. The results from this study showed the possibility of multiple source kitchens in the Cambrian–lower Ordovician portion of Tarim Basin.

  15. The environmental signal of an early Holocene pollen record from the Shiyang River basin lake sediments, NW China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Pollen analyses of 85 samples from the Sanjiaocheng section well along the margin of a palaeolake at the end of the Shiyang River, NW China, show that Picea and Sabina dominate the pollen assemblage. Together they reach as high as 40%-60%, with the percentage of Picea varying inversely with that of Sabina. Similar results were obtained from another section in the Shiyang River drainage.Using modern ecological habitat relationship analogues, pollen transport characteristics, and the overall pollen assemblage, we propose that both Picea and Sabina pollen were transported by the river from the mountains at the upper reaches of the Shiyang River, and that the assemblage is more indicative of changes in upland vegetation than of local conditions near the section. This interpretation is supported by pollen data derived from surface samples, water samples,and riverbed samples. Using a moisture indicator (the Picea to Sabina ratio) and calculated pollen concentrations, we identify a series of palaeoenvironmental changes during the early Holocene (10 6.3 14C kaBP).

  16. The first dinosaur tracksite from Xinjiang, NW China (Middle Jurassic Sanjianfang Formation, Turpan Basin)——a preliminary report

    Institute of Scientific and Technical Information of China (English)

    Oliver WINGS; Rico SCHELLHORN; Heinrich MALLISON; Ben THUY; Wenhao WU; Ge SUN

    2007-01-01

    A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.

  17. Thermal and maturation history of Jurassic source rocks in the Kuqa foreland depression of Tarim Basin, NW China

    Science.gov (United States)

    Tang, Xiaoyin; Yang, Shuchun; Hu, Shengbiao

    2014-08-01

    Kuqa foreland depression of the Tarim Basin is one of the largest gas production provinces in China. Thermal history reconstruction using vitrinite reflectance data indicates that the palaeo-heat flow in Kuqa depression was relatively high (50-55 mW/m2) during the Mesozoic, but gradually decreased during the Cenozoic to reach the present value of 40-50 mW/m2. The cooling of the Kuqa depression is probably attributed to the crust thickening and the rapid sedimentary rate. The Jurassic source rocks entered conventional oil window at 100 Ma, and began to generate gas at approximately 75 Ma in the Kelasu area. Thermal maturation of the Jurassic source rocks accelerated significantly since 23.3 Ma, especially in the recent 5.2 Ma. In this foreland depression, source rock maturation, which is likely controlled mainly by burial history, also influenced by the presence of fault thrusting and salt-bearing formations.

  18. Dibenzofuran Series in Terrestrial Source Rocks and Crude Oils and Applications to Oil-Source Rock Correlations in the Kuche Depression of Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    李景贵; 李梅; 王兆云

    2004-01-01

    Ten series of aromatic hydrocarbon compounds (biphenyl, naphthalene, phenanthrene, anthracene, retene, chrysene, benzoanthracene, dibenzofuran, fluorene, dibenzothiophene) isolated from seven Triassic and Jurassic lacustrine mudstone samples and three swamp coal samples, as well as five crude oil samples collected in the Kuche depression of the Tarim Basin, NW China, have been analysed by GC-MS techniques. It is found that the relative abundances of dibenzofuran series are higher in the three swamp coal samples than those in the lacustrine mudstone samples. Based on the similar relative abundances of dibenzofuran series, especially dibenzofuran compound, in the TICs of aromatic hydrocarbons, crude oils from wells SA3 (K), YTK5 (E, K) and QL1 (E) are thought to have been derived predominantly from the coals of the Lower Jurassic Yangxia Formation or Middle Jurassic Kezilenuer Formation, whereas those from wells YM7 (O) and YH1 (E) were derived mainly from Triassic and Jurassic lacustrine mudstones in the Kuche depression. This is the first report about how to distinguish coal-generated oils from lacustrine mudstone-generated oils in the Kuche depression in terms of the dibenzofuran series. The present paper has enlightening and directive significance for further oil-source rock correlations and oil and/or gas exploration in the Kuche depression of the Tarim Basin.

  19. Hydrogen isotopic compositions, distributions and source signals of individual n-alkanes for some typical crude oils in Lunnan Oilfield, Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    LU; Hong; LI; Chao; SUN; Yongge; PENG; Ping'an

    2005-01-01

    Isotopic compositions of carbon-bound hydrogen in individual n-alkanes from several typical crude oil samples from Lunnan Oilfield, Tarim Basin, NW China, were firstly measured using newly developed gas chromatography-thermal conversion-isotope ratio mass spectrometry. The similar range of δD of individual n-alkanes of crude oils among reservoirs of different geological times reflects that hydrocarbons are all derived from the same marine depositional environment. Compared to the theoretic value (-150‰) and the reported δD values (nC13―nC27, -160‰―-90‰) of individual n-alkanes for Ordovician-sourced crude oils in the Canadian Williston Basin, the hydrogen isotopic composition of individual n-alkanes in crude oils from Lunnan Oilfield is characterized by heavy hydrogen isotopic values (nC12―nC27, -120‰―-60‰). In terms of the factors that control the fractionation of hydrogen isotopes, relatively saline depositional environment and higher thermal maturation were attributed to the heavy δD values of individual n-alkanes in crude oils from Lunnan Oilfield.

  20. Occurrence, thermal evolution and primary migration processes derived from studies of organic matter in the Lucaogou source rock at the southern margin of the Junggar Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Lucaogou Formation carbonate-rich oil shale source rock is exposed at the southern margin of the Junggar Basin, Xinjiang, NW China. We have sampled it in detail and conducted microstructural, mineralogical and geochemical studies, including thin section petrography, UV fluorescence petrography, X-ray diffraction, vitrinite reflectance, bitumen reflectance, fluid inclusion analysis and Raman spectroscopy. Organic matter is disseminated through the carbonate-bearing siltstone source rocks and concentrated in numerous bedding parallel stylolites and in two sets of carbonate veins, one along bedding parallel fractures and the other cross-cutting stylolites and bedding. The research about maturity of organic matter finds vitrinite reflectance values increase from the dispersed kerogen (0.64%) to the stylolites (the one of oriented vitrinite is 0.72% and the one of migrated bitumen is 2.38%); Homogenization temperatures of fluid inclusions in veins containing hydrocarbon fluid inclusions show an increase from 178.5℃ in the bedding parallel veins to 222℃ in the cross-cutting veins, confirmed by Raman spectroscopy. These results support a model of progressive heating accompanied by fluid loss during later stages of thermal maturation of source rock and the onset of primary migration. Obviously, the occurrence of organic matter is the trace of hydrocarbon primary migration, and the bedding lamination surfaces and cross-cutting fissures are the principal pathways of hydrocarbon-bearing fluids migration. Bedding lamination surfaces evolved into stylolites along the earliest primary migration pathways, followed by bedding parallel and cross-cutting fissures.

  1. Reconstructing multiple arc-basin systems in the Altai-Junggar area (NW China): Implications for the architecture and evolution of the western Central Asian Orogenic Belt

    Science.gov (United States)

    Li, Di; He, Dengfa; Tang, Yong

    2016-05-01

    The Altai-Junggar area in northwestern China is a critical region to gain insights on the tectonic framework and geological evolution of the western Central Asian Orogenic Belt (CAOB). In this study, we report results from integrated geological, geochemical and geophysical investigations on the Wulungu Depression of the Junggar Basin to determine the basement nature of the basin and understand its amalgamation history with the Chinese Altai, within the broad tectonic evolution of the Altai-Junggar area. Based on borehole and seismic data, the Wulungu Depression is subdivided into two NW-trending tectonic units (Suosuoquan Sag and Hongyan High) by southward-vergent thrust faults. The Suosuoquan Sag consists of the Middle-Late Devonian basaltic andesite, andesite, dacite, tuff, tuffaceous sandstone and tuffite, and the overlying Early Carboniferous volcano-sedimentary sequence with lava flows and shallow marine sediments from a proximal juvenile provenance (zircon εHf(t) = 6.0-14.9), compared to the Late Carboniferous andesite and rhyolite in the Hongyan High. Zircon SIMS U-Pb ages for dacites and andesites indicate that these volcanics in the Suosuoquan Sag and Hongyan High erupted at 376.3 Ma and 313.4 Ma, respectively. The Middle-Late Devonian basaltic andesites from well LC1 are calc-alkaline and exhibit primitive magma-like MgO contents (7.9-8.6%) and Mg# values (66-68), with low initial 87Sr/86Sr (0.703269-0.704808) and positive εNd(t) values (6.6-7.6), and relatively high Zr abundance (98.2-116.0 ppm) and Zr/Y ratios (5.1-5.4), enrichment in LREEs and LILEs (e.g., Th and U) and depletion in Nb, Ta and Ti, suggesting that they were probably derived from a metasomatized depleted mantle in a retro-arc extensional setting. The well LC1 andesitic tuffs, well L8 dacites, well WL1 dacitic tuffs and well L5 andesites belong to calc-alkaline and metaluminous to peraluminous (A/CNK = 0.8-1.7) series, and display low Mg# values (35-46) and variably positive εNd(t) (4

  2. Tectonic evolution of Tarim basin in Cambrian-Ordovician and its implication for reservoir development, NW China

    Science.gov (United States)

    Bingsong, Yu; Zhuang, Ruan; Cong, Zhang; Yinglu, Pan; Changsong, Lin; Lidong, Wang

    2016-03-01

    In order to find the impact of regional tectonic evolution of Tarim basin on the inside distribution of sedimentary facies and reservoir development, this paper, based on the research of plate-tectonic evolution of Tarim basin, conducts an in-depth analysis on the basin's inside sedimentary response to the Eopaleozoic regional geodynamic reversion from extension to convergence around Tarim plate, and concludes that the regional geodynamic environment of surrounding areas closely contributes to the formation and evolution of paleo-uplifts, differentiation of sedimentary facies in platform, distribution of high-energy reef and bank facies belts, conversion of sedimentary base level from fall to rise, obvious change of lithology from dolomite to limestone, and formation of several unconformity surfaces in Ordovician system in the basin. A series of sedimentary responses in the basin are controlled by regional dynamic setting, which not only controls the distribution of reservoirs in reef and bank facies but also restricts the development and distribution of karst reservoirs controlled by the unconformity surfaces. This offers the macro geological evidences for us to further analyze and evaluate the distribution of favorable reservoirs.

  3. Tectonic evolution of Tarim basin in Cambrian–Ordovician and its implication for reservoir development, NW China

    Indian Academy of Sciences (India)

    Yu Bingsong; Ruan Zhuang; Zhang Cong; Pan Yinglu; Lin Changsong; Wang Lidong

    2016-03-01

    In order to find the impact of regional tectonic evolution of Tarim basin on the inside distribution of sedimentary facies and reservoir development, this paper, based on the research of plate-tectonic evolution of Tarim basin, conducts an in-depth analysis on the basin’s inside sedimentary response to the Eopaleozoicregional geodynamic reversion from extension to convergence around Tarim plate, and concludes that the regional geodynamic environment of surrounding areas closely contributes to the formation and evolution of paleo-uplifts, differentiation of sedimentary facies in platform, distribution of high-energyreef and bank facies belts, conversion of sedimentary base level from fall to rise, obvious change of lithology from dolomite to limestone, and formation of several unconformity surfaces in Ordovician system in the basin. A series of sedimentary responses in the basin are controlled by regional dynamic setting, which not only controls the distribution of reservoirs in reef and bank facies but also restricts the development and distribution of karst reservoirs controlled by the unconformity surfaces. This offers the macro geological evidences for us to further analyze and evaluate the distribution of favorable reservoirs.

  4. EVIDENCE OF NEOTECTONIC IMPACT ON A LARGE SEDIMENTARY BASIN BETWEEN TIBETAN PLATEAU AND GOBI ALTAY,NW CHINA

    Institute of Scientific and Technical Information of China (English)

    K.ttartmann; B.Wünnemann; Hucai Zhang

    2009-01-01

    The Ejina(Gaxun Nur)Basin-enclosed by the Tibetan Plateau in the south and the Gobi Altay in the north has continuously evolved as a strong continental endorheic depositional environment.Medium scale geomorphological mapping by Landsat-and Corona-Images as well as SRTM-topographic data,combined with field-surveys and geophysical investigation provides evidence for tectonic impact on sedimentary processes during the Late Quaternary.Analyses of SRTM-Data and Landsat-Images reveal a system of up to 20m high inverted channels developed on the inactive eastern part of the large Hei river drainage delta south of the ancient lake Juyanze.The complex evolution of these landforms requires a relative lowering of the lake basin at least two times since the last 40ka.A 26m high cliff section of gravel-covered lake sediments within the Juyanze paleolake indicates a strong subsidence of the lake bottom of 10m/1000yrs since 18kaB.P.North of Ejina river oasis a distinct north-south striking scarp up to 13m high constitutes the eastern margin of the Gaxun Nur.Palaeodrainage channels derived from the Gobi Altay.They display a sinistral offset of some decametres along a set of WE-trending faults.The rhombic shape of the modern dry Gaxun Nur,fossil cliffs,well preserved beach ridges along the margins of the palaeolake system as well as gravel covered topsets of lacustrine sediments indicate local displacements of morphological features.The displacements of lake sediments at the southern margin of the modern Gaxun Nut Basin imply a subsidence of at least 0.81m/1000 yrs since 25kaB.P.as a result of a pull-apart development due to the left stepping faults in a sinistral system.

  5. Carbonate cementation-dissolution in deep-seated sandstones near the overpressure top in central Junggar Basin, Xinjiang, NW China

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi; HE Sheng; WANG Furong; HE Zhiliang; WU Hengzhi; MENG Xianlong

    2009-01-01

    Fluid/rock interaction occurs frequently in the sandstones near the overpressure top in central Junggar Basin, and carbonate cementation-dissolution is related closely to the formation of secondary pores in the reservoir sandstones. From petrological, hydrochemical and fluid-inclusion studies of the deep-seated sandstones near the overpressure top in central Junggar Basin and the carbon and oxygen isotopic characteristics of carbonate cements in those sandstones, the following conclusions can be drawn: (1) Carbonates are the major cements. Two-stage cemen-tation was commonly developed, with late-stage ferroan carbonate cementation being dominant; several secondary porosity zones were developed vertically in the sandstones near the overpressure top, and there is a mutually com-pensatory relationship between the carbonate contents and the mean porosity; (2) the alkalescent formation-water chemical environments are in favor of carbonate precipitation; (3) there were two phases of thermal fluid activity which are related to the late-stage carbonate cementation-dissolution; (4) with the overpressure top as the boundary, carbonate cements in the sandstones have slightly negative δ13C and δ180 values, showing such a variation trend that the δ13C and δ18O values near the coal-bearing Jurassic strata are lighter, those in the overpressure top are heavier, and those at the upper part of the overpressure top are lighter, which is considered to be the result of kinetic isotope fractionation driven by episodically overpressured fluid flow; (5) carbonate cementation is closely associated with the decarboxylation of organic acids, and secondary porosity zones resultant from dissolution by organic acids and CO2 derived from Jurassic coal-beating strata, are the most important reservoir space of hydrocarbon, Studies of the mechanisms of carbonate cementation-dissolution and formation of secondary pores in the deep-seated sandstones near the overpressure top are of great

  6. Effect of Water Washing on Hydrocarbon Compositions of Petropleum Sandstone Reservoir Rocks in Tarim Basin,NW China

    Institute of Scientific and Technical Information of China (English)

    张敏; 张俊

    2000-01-01

    Gross compositions and distribution of saturated and aromatic hydrocarbons in Carboniferous sandstone reservoire rocks in oil and water zones for Tzhong-10 well of the Zhongyang Uplift in the Tarim Basin were studied in dteail by means of Rock-Eval Pyrolysis,thin-chromatograph-flame ionization detection(TLC-FID),gas chromatography,gas chromatography-mass spectrometry.The results suggest that the gross composition of reservoir hydrocarbons between the oil zone and the water zone show significant differences,Water wahing has a dramatic effect on saturated hydrocarbon blomarkers,especially drimane series compounds,Drimane series compounds in the water zone have been depleted completely.However,the contents of tricyclic iterpanes and pentacyclic triterpanes tend to decrease slightly,but the water-zone reservoir hydrocarbons contian a large amount of gammacerane.This suggests that gammacerane be more resistant to water washing than diterpanes and homohopanes.The contents of pregnane,homopregrane,diasteranes relastively decrease as a result of water washing.Water washing has a noticeable effect on polycyclic aromatic hydrocarbon compounds,especially aromatic sulfur compounds,and the contents of dibenzothiophene series compounds and benzonaplyiothipophene decrease significantly as a result of water washing.However,the conterts of bicyclic and tricyclic aromatic hydrocarbons decrase slightly and those of tetracyclic and pentacyclic aromatic hydrocarbons,especially benzofluoranthene and benzopyrenes,increase markedly owing to adecrease in light aromatie hydrocarbons as a result of water washing.

  7. Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin, NW China, and Its Geological Significance

    Institute of Scientific and Technical Information of China (English)

    LIU Chunyan; LIN Changsong; WANG Yi; WU Maobing

    2008-01-01

    With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oilfieid of the Tarim Basin, two stages of burial dissolution were put forward as an in-source dissolution and out-source dissolution based on macro-microcosmic petrology and geochemistry features. The main differences in the two stages arc in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in-source fuid came from organic matter in the granule limestone itself, but the out-source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in-source and the out-source dissolutions. The granule limestone firstly formed unattached pinholes under in-source dissolution in situ, and afterwards suffered wider dissolution with out-source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.

  8. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    Directory of Open Access Journals (Sweden)

    Yun Li

    Full Text Available Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin.

  9. Source facies of the Paleozoic petroleum systems in the Tabei uplift, Tarim Basin, NW China: implications from aryl isoprenoids in crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Yongge Sun; Shiping Xu; Hong Lu; Pingxia Cuai [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou (China). SKLOG

    2003-04-01

    Aryl isoprenoids have been detected for the first time in crude oils from Paleozoic petroleum systems in the Tabei uplift, Tarim Basin, northwestern China. The principal compounds possess the 1-alkyl-2,3,6-trimethyl substitution pattern characteristic of diaromatic carotenoids found in the Chlorobiaceae family of photosynthetic sulfur bacteria, with a predominance of C{sub 13} - C{sub 23} homologues in these samples. Flash pyrolysates of the asphaltene fractions isolated from crude oils show an unusual abundance of 1,2,3,4-tetramethylbenzene, an indicator for a significant contribution of diaromatic carotenoids to the source kerogen of these oils. The wide distribution of these compounds in crude oils reveals that penetration of the photic zone by sulfidic waters during deposition enabled prolific growth of photosynthetic green sulphur bacteria (Chlorobiaceae). This suggests that the source rocks for the Paleozoic petroleum systems in the Tabei uplift were likely deposited under euxinic conditions with sulfate and sulfide-rich water bodies, which doesn't support previously published conclusions of a Middle-Upper Ordovician source that marks the slope facies at the margins of structural uplifts. (author)

  10. Sulfur isotopic compositions of individual organosulfur compounds and their genetic links in the Lower Paleozoic petroleum pools of the Tarim Basin, NW China

    Science.gov (United States)

    Cai, Chunfang; Amrani, Alon; Worden, Richard H.; Xiao, Qilin; Wang, Tiankai; Gvirtzman, Zvi; Li, Hongxia; Said-Ahmad, Ward; Jia, Lianqi

    2016-06-01

    During thermochemical sulfate reduction (TSR), H2S generated by reactions between hydrocarbons and aqueous sulfate back-reacts with remaining oil-phase compounds forming new organosulfur compounds (OSCs) that have similar δ34S values to the original sulfate. Using Compound Specific Sulfur Isotope Analysis (CSSIA) of alkylthiaadamantanes (TAs), alkyldibenzothiophenes (DBTs), alkylbenzothiophenes (BTs) and alkylthiolanes (TLs), we have here attempted to differentiate OSCs due to primary generation and those due to TSR in oils from the Tarim Basin, China. These oils were generated from Cambrian source rocks and accumulated in Cambrian and Ordovician reservoirs. Based on compound specific sulfur isotope and carbon isotope data, TAs concentrations and DBT/phenanthrene ratios, the oils fall into four groups, reflecting different extents of source rock signal, alteration by TSR, mixing events, and secondary generation of H2S. Thermally stable TAs, that were produced following TSR, rapidly dominate kerogen-derived TAs at low to moderate degrees of TSR. Less thermally stable TLs and BTs were created as soon as TSR commenced, rapidly adopted TSR-δ34S values, but they do not survive at high concentrations unless TSR is advanced and ongoing. The presence of TLs and BTs shows that TSR is still active. Secondary DBTs were produced in significant amounts, sufficient to dominate kerogen-derived DBTs, only when TSR was at an advanced extent. The difference in sulfur isotopes between (i) TLs and DBTs and (ii) BTs and DBTs and (iii) TAs and DBTs, represents the extent of TSR while the presence of TAs at greater than 20 μg/g represents the occurrence of TSR. The output of this study shows that compound specific sulfur isotopes of different organosulfur compounds, with different thermal stabilities and formation pathways, not only differentiate between oils of TSR and non-TSR origin, but can also reveal information about relative timing of secondary charge events and migration

  11. The significance of 24-norcholestanes, triaromatic steroids and dinosteroids in oils and Cambrian-Ordovician source rocks from the cratonic region of the Tarim Basin, NW China

    Science.gov (United States)

    Li, Meijun; Wang, T.-G.; Lillis, Paul G.; Wang, Chunjiang; Shi, Shengbao

    2012-01-01

    Two oil families in Ordovician reservoirs from the cratonic region of the Tarim Basin are distinguished by the distribution of regular steranes, triaromatic steroids, norcholestanes and dinosteroids. Oils with relatively lower contents of C28 regular steranes, C26 20S, C26 20R + C27 20S and C27 20R regular triaromatic steroids, dinosteranes, 24-norcholestanes and triaromatic dinosteroids originated from Middle–Upper Ordovician source rocks. In contrast, oils with abnormally high abundances of the above compounds are derived from Cambrian and Lower Ordovician source rocks. Only a few oils have previously been reported to be of Cambrian and Lower Ordovician origin, especially in the east region of the Tarim Basin. This study further reports the discovery of oil accumulations of Cambrian and Lower Ordovician origin in the Tabei and Tazhong Uplifts, which indicates a potential for further discoveries involving Cambrian and Lower Ordovician sourced oils in the Tarim Basin. Dinosteroids in petroleum and ancient sediments are generally thought to be biomarkers for dinoflagellates and 24-norcholestanes for dinoflagellates and diatoms. Therefore, the abnormally high abundance of these compounds in extracts from the organic-rich sediments in the Cambrian and Lower Ordovician and related oils in the cratonic region of the Tarim Basin suggests that phytoplankton algae related to dinoflagellates have appeared and might have flourished in the Tarim Basin during the Cambrian Period. Steroids with less common structural configurations are underutilized and can expand understanding of the early development history of organisms, as well as define petroleum systems.

  12. Abrupt Holocene changes of the Asian monsoon at millen-nial- and centennial-scales:Evidence from lake sediment document in Minqin Basin,NW China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Considerable research is now focusing on abrupt Holocene changes at millennial- and centennial-scales all over the world. This study shows that the changes in the Holocene summer monsoon can be divided into two main periods, based on climatic proxy records of lake sediments from the Sanjiaocheng section located at the NW boundary of the summer monsoon, Gansu Province. The early and middle Holocene was humid with stronger summer monsoon, while the late Holocene is dry with weak summer monsoon. Detailed results also show a series of millennial- and centennial-scale changes in the intensity of the summer monsoon, with a periodicity of 1600 years during the whole Holocene, and with a periodicity of 800 years during the early Holocene. Ten dry events during the Holocene are associated with the weakening of the summer monsoon. These rapid climatic changes may be representative of a global climatic change pattern during the Holocene.

  13. Mn content of reservoir calcite cement: A novel inorganic geotracer of secondary petroleum migration in the tectonically complex Junggar Basin (NW China)

    Institute of Scientific and Technical Information of China (English)

    CAO; Jian; HU; WenXuan; YAO; SuPing; ZHANG; YiJie; WANG; XuLong; ZHANG; YueQian; TANG; Yong; SHI; XinPu

    2007-01-01

    Electronic probe microanalysis (EPMA) results of reservoir calcite cement from fourteen core samples in the Junggar Basin show that Mn-content varies largely between different samples from below the detect limitation to 4.14%, while it displays a generally good correlation with oil-gas shows. This, therefore, likely indicates that concentration of the Mn-content of the calcite cement has a close relation to the intensity of petroleum fluid charging during hydrocarbon secondary migration. In order to assess this hypothesis, oxygen and strontium isotopic measurements on sixteen calcite veins host in source sequences were carried out to investigate the feature of the oil-source petroleum fluid. Analytical results imply that during hydrocarbon generation and migration, deep hot fluid has dissolved volcanic minerals interlined between mudstone source rocks. As Mn is a kind of typical trace element enriched in volcanic rocks, it is reasonable to conclude that the petroleum fluid formed in the source sequences would be Mn-rich. Consequently, calcite cements precipitated from such Mn-rich petroleum fluid would be Mn-rich accordingly. Due to the geologic chromatographic effect during migration along reservoir rocks, the decreasing of the Mn-content of the reservoir calcite cements indicates the migration direction. Then, this novel geotracer was further successfully applied in the study of hydrocarbon migration in the Junggar Basin in combination with organic geochemical analyses during the hydrocarbon migration. The Mn content of the reservoir calcite cement appears promising as a novel inorganic geotracer for the petroleum migration. This paper represents a search for novel indicators of secondary petroleum migration in tectonically complex basins based on fundamentals of the reservoir fluid-rock interactions.

  14. REE Compositions of Lower Ordovician Dolomites in Central and North Tarim Basin, NW China: A Potential REE Proxy for Ancient Seawater

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuefeng; HU Wenxuan; JIN Zhijun; ZHANG Juntao; QIAN Yixiong; ZHU Jingquan; ZHU Dongya; WANG Xiaolin; XIE Xiaomin

    2008-01-01

    Rare earth dement compositions of Lower Ordovician dolomites in the Central and Northern Tarim Basin are studied. Most dolomite samples are more or less contaminated by clay minerals. Their rare earth element compositions have been consequently changed, showing both seawater-like and non-seawater-like features. The clay contamination should be disposed before the REE data are used. Through ICP-MS and ICP-AES analyses, the REE features are well documented. The clay contamination is quantitatively determined by microscopic investigation, trace elements and REE contents. The dolomites, at least in the Tarim Basin, are thought to be pure when their total LREE contents are less than 3x10-6. Through comparison, the pure dolomites show similarities in REE patterns but differences in REE contents with co-existing pure limestone, which indicates that dolomitization may slightly change the REE compositions. Nevertheless, whatever the change is, the pure dolomites may act as a potential REE proxy for Ordovician seawater, which would be significant for ancient massive dolomite strata that lack limestone.

  15. Cenozoic faults and faulting phases in the western Tarim Basin (NW China): Effects of the collisions on the southern margin of the Eurasian Plate

    Science.gov (United States)

    Li, Yue-Jun; Zhang, Qiang; Zhang, Guang-Ya; Tian, Zuo-Ji; Peng, Geng-Xin; Qiu, Bin; Huang, Zhi-Bin; Luo, Jun-Cheng; Wen, Lei; Zhao, Yan; Jia, Tie-Gan

    2016-12-01

    The Bachu Rise in the western Tarim Basin is the fore-bulge of the Kunlun late Cenozoic intra-continental foreland basin system formed under the far-field effect of India-Asia collision. Cenozoic faults and faulting are abnormally developed in the Bachu Rise and its adjacent area. Taking the Niaoshan-Gudongshan area on the southern boundary of the Bachu Rise as the key study area, 5 Cenozoic faulting phases were identified in the Bachu Rise and its adjacent area after careful seismic interpretation. They are end Cretaceous ∼ beginning Paleogene (ca. 65 Ma) décollement-thrusting, end Paleogene ∼ beginning Neogene (ca. 23 Ma) décollement-thrusting, end Miocene ∼ beginning Pliocene (ca. 5 Ma) basement-involved thrusting, late Pliocene ∼ early Pleistocene (ca. 3-2 Ma) normal faulting, middle Pleistocene ∼ Holocene (ca. <1.5 Ma) décollement-thrusting and strike-slip faulting. The Middle Cambrian and Paleogene gypsum-salt layers serve as the two main décollement layers in the study area. Thrusting of ca. 65 Ma was under the far-field effect of the collision between Lhasa (part of the Cimmerian Continent) and Asia; and the other 4 Cenozoic faulting phases were all under the far-field effect of the India-Asia collision. The late Cenozoic faulting is characterized by pulse thrust. There is one tectonic pause between each two successive thrust pulses. The compressive tectonic stress is weaker and even evolved into a slight tensional tectonic stress and forms normal fault in the tectonic pauses.

  16. Vertical structure and dominating factors of sand body during Late Triassic Chang 9 time of Yanchang Formation in Ordos Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    丁熊; 陈景山; 谭秀成; 林丹; 赵子豪; 姚泾利; 邓秀芹; 李元昊

    2015-01-01

    Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9 sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel, natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform+infundibuliform, campaniform+infundibuliform, box shape+campaniform, box shape+infundibuliform, and finger+finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment, sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.

  17. Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    MA Anlai; ZHANG Shuichang; ZHANG Dajiang; JIN Zhijun; MA Xiaojuan; CHEN Qingtang

    2005-01-01

    The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations. The RICO products included n-alkanoic acids, α, ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bounded on the asphaltenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C2s sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tahe oilfields.

  18. Application of Spectral Decomposition to Detection of Fracture-Cavity Carbonate Reservoir Beds in the Tahe Oilfield, Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaoping; YANG Xiaolan; ZHANG Yazhong; HAN Long

    2008-01-01

    Ordovician fracture-cavity carbonate reservoir beds are the major type of producing formations in the Tahe oilfieid, Tarim Basin. The seismic responses of these beds clearly changes depending on the different distance of the fracture-cavity reservoir bed from the top of the section. The seismic reflection becomes weak or is absent when the fracture-cavity reservoir beds are less than 20 ms below the top Ordovician. The effect on top Ordovician reflection became weaker with deeper burial of fracture-cavity reservoir beds but the developed deep fracture-cavity reservoir beds caused stronger reflection in the interior of the Ordovician. This interior reflection can be divided into strong long-axis, irregular and bead string reflections, and was present 80 ms below the top Ordovician. Aimed at understanding reflection characteristics, the spectral decomposition technique, which uses frequency to "tune-in" bed thickness, was used to predict Ordovician fracture-cavity carbonate formations in the Tahe oilfield. Through finely adjusting the processing parameters of spectral decomposition, it was found that the slice at 30 Hz of the tuned data cube can best represent reservoir bed development. Two large N-S-trending strong reflection belts in the mid-western part of the study area along wells TK440- TK427-TK417B and in the eastern part along wells TK404-TK409 were observed distinctly on the 30 Hz slice and 4-D time-frequency data cube carving. A small N-S trending reflection belt in the southern part along wells T403-TK446B was also clearly identified. The predicted reservoir bed development area coincides with the fracture-cavities connection area confirmed by drilling pressure testing results. Deep karst cavities occur basically in three reservoir bed-development belts identified by the Ordovician interior strong reflection. Spectral decomposition proved to be a useful technique in identifying fracture-cavity reservoir beds.

  19. Energy Industry Expo opens in NW China

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The Fourth China (Taiyuan) International Energy Industry Expo was recently held in Taiyuan, capital of coal-rich Shanxi Province, to discuss the latest trends in China's energy industries. Some 30,000 people, including representatives from 137 companies fi'om 18 countries and regions, attended the Expo, which featured demonstrations of industry breakthroughs in the fields of coal and coalbed gas, water, electricity, natural gas and new energies. Running under a theme of "green energy and transformation", the three-day event also allowed Shanxi,

  20. Origin and evolution of marginal basins of the NW Pacific: Diffuse-plate tectonic reconstructions

    CERN Document Server

    Xu, Junyuan; Ben-Avraham, Zvi; Yu, Ho-Shing

    2012-01-01

    Formation of the gigantic linked dextral pull-apart basin system in the NW Pacific is due to NNE- to ENE-ward motion of east Eurasia. This mainly was a response to the Indo-Asia collision which started about 50 Ma ago. The displacement of east Eurasia can be estimated using three aspects: (1) the magnitude of pull-apart of the dextral pull-apart basin system, (2) paleomagnetic data from eastern Eurasia and the region around the Arctic, and (3) the shortening deficits in the Large Tibetan Plateau. All the three aspects indicate that there was a large amount (about 1200 km) of northward motion of the South China block and compatible movements of other blocks in eastern Eurasia during the rifting period of the basin system. Such large motion of the eastern Eurasia region contradicts any traditional rigid plate tectonic reconstruction, but agrees with the more recent concepts of non-rigidity of both continental and oceanic lithosphere over geological times. Based on these estimates, the method developed for resto...

  1. Chronology and origin of VMS deposits in Xinjiang, NW CHINA

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fuwen(陈富文); LI; Huaqin(李华芹); WANG; Denghong(王登红); XIE; Caifu(谢才富); LU; Yuanfa(路远发)

    2002-01-01

    VMS deposits in Xinjiang, NW China are widespread in the Altay, Tianshan and West Kunlun orogenic belt, mainly formed during the Proterozoic rifting and Phanerozoic post-orogenic extension and are related to the bimodal volcanism. The VMS deposits are middle and small in scale. According to assemblages of metallogenetic elements, they can be divided into four types (Cu-Zn, Cu-S, Pb-Zn-Cu and Pb-Zn types) with the Cu-Zn and Pb-Zn types being the most important ones. Research of isotopic chronology shows that the VMS deposits in Xinjiang were formed during the Proterozoic, Ordovician, Deovonian, Carboniferous and Permian periods and usually underwent multi-stage mineralization, especially the large-sized deposits usually have post- volcanic superimposed mineralization by tectonomagmatic or metamorphic hydrothermal metallogenic fluids.

  2. Paleozoic Accretionary Terranes in Northern Tianshan,NW China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    During the paleozoic,the Northern Tianshan region of China in Central Asia consists of 7 allochthonous terranes which were situated in the ancient sino-Mongolian Ocean as volcanic arcs and splitted continental fragments.The tectonic framework was similar to that of Southwest pacific today,In the Late Paleozoic,these terranes started mutual amalgamation to cause strong thrusting.At thd end of Carboniferous,the Sino-mongolian ocean including several inter-terrane small sea basins closed and these terranes accreted on the margins of the Siberian and Tarim continents,The 6 ophiolitic zones zomong the terranes recorded this collision event.

  3. Origin and lateral migration of linear dunes in the Qaidam Basin of NW China revealed by dune sediments, internal structures, and optically stimulated luminescence ages, with implications for linear dunes on Titan: discussion

    Science.gov (United States)

    Rubin, David M.; Rubin, Alan M.

    2013-01-01

    Zhou et al. (2012) proposed that longitudinal dunes in the Qaidam Basin, China, formed like yardangs: by erosion into sediment that was not deposited by those dunes. Because erosion occurs on the upwind flanks of most migrating dunes (Rubin and Hunter, 1982, 1985), the key to demonstrating a yardang-like origin is to show that the dunes did not deposit the strata that they contain. Zhou et al. made this argument by proposing that: (1) The dunes have not deposited cross-strata in the past 810 yr. (2) Cross-bedding within the dunes was not deposited by the dunes on the present-day land surface, but rather by older dunes that had a different morphology. (3) The present dunes are a later generation, “most likely of erosional origin similar to yardangs with orientations controlled by strikes of joints,” (p. 1147). (4) Rates of deflation in the dune field have been extremely high for the past 810–2440 yr. This commentary reviews these conclusions, reviews contradictory observations, and considers alternative interpretations.

  4. Cyclone trends constrain monsoon variability during Late Oligocene sea level highstands (Kachchh Basin, NW India)

    OpenAIRE

    Reuter, M.; W. E. Piller; M. Harzhauser; Kroh, A

    2013-01-01

    Important concerns about the consequences of climate change for India are the potential impact on tropical cyclones and the monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin) as an indicator of tropical cyclone activity along the NW Indian coast during the Late Oligocene warming period (~27–24 Ma). Direct proxies providing information about the atmospheric circulation dynamics over the Indian subcontinent at this ...

  5. Cyclone trends constrain monsoon variability during late Oligocene sea level highstands (Kachchh Basin, NW India)

    OpenAIRE

    Reuter, M.; W. E. Piller; M. Harzhauser; Kroh, A

    2013-01-01

    Climate change has an unknown impact on tropical cyclones and the Asian monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin) as a recorder of tropical cyclone activity along the NW Indian coast during the late Oligocene warming period (~ 27–24 Ma). Proxy data providing information about the atmospheric circulation dynamics over the Indian subcontinent at this time are important since it corresponds to a major climate reorga...

  6. 应用烃类流体包裹体GOI和成分研究凝析气藏成藏过程:以准噶尔盆地莫索湾地区为例%Integrate GOI and composition data of oil inclusions to reconstruct petroleum charge history of gas-condensate reservoirs: example from the Mosuowan area, central Junggar basin (NW China)

    Institute of Scientific and Technical Information of China (English)

    曹剑; 金之钧; 胡文瑄; 谢小敏; 王绪龙; 姚素平

    2007-01-01

    The Grains containing Oil Inclusions (GOI) data in currently gas/condensate-bearing Jurassic and Cretaceous reservoir sandstones of Well Pen 5 (the Mosuowan area of central Junggar Basin, NW China) are generally greater than the empirical threshold line of 5%. This is consistent with the gas-condensate section originally containing a palaeo-oil column. In order to assess the origin of the oil trapped in the oil inclusion and its relationship to the free oil/gas-condensate, a detailed molecular geochemical study was carried out for correlation between the free and inclusion oils. The paleo oil is most likely sourced from the Lower Permian Fengcheng Formation, which generated hydrocarbons primarily during Late Triassic and the oils were later secondarily altered and dysmigrated along faults likely during Late Jurassic-Early Cretaceous. In contrast, the current reservoired oil/gas-condensate mainly derived from the Middle Permian Lower Wuerhe Formation, whose peak generation time last from Late Cretaceous even to the present. This paper showed that integrated oil-bearing fluid inclusion analyses have likely allowed a complex multi-phase charge history to be recognized and resolved with a high degree of confidence.

  7. Geochemistry and petrology of nephrite from Alamas, Xinjiang, NW China

    Science.gov (United States)

    Liu, Yan; Deng, Jun; Shi, Guanghai; Yui, Tzen-Fu; Zhang, Guibin; Abuduwayiti, Maituohuti; Yang, Liqiang; Sun, Xiang

    2011-08-01

    The Hetian nephrite deposit is one of the largest nephrite deposits worldwide. Located within the Hetian deposit, Xinjiang, Northwest China, the Alamas ore body occurs as veins on the contact between the Late Variscan granodiorite and Precambrian dolomitic marble. Petrographic studies and electronic microprobe analyses reveal two possible nephrite formation processes: (1) dolomitic marble → tremolite and (2) dolomitic marble → diopside → tremolite. Nephrite veins show continuous coloration zones, ranging from white and white-green zones to a green zone towards the granodiorite, with increasing concentrations of Cr, FeO and TFe 2O 3. All these nephrite samples have quite low Cr and Ni contents (8.95-178.7 ppm and 0.05-3.95 ppm, respectively) relative to serpentinite-related nephrite (Cr 2O 3, 0.07-0.43 wt.%; NiO, 0.08-0.36 wt.%). Their bulk-rock REE patterns exhibit strong negative Eu anomalies (0.03-0.21) with declined LREE, flat HREE and low ΣREE concentration (2.84-84.81 ppm), similar to those of host dolomitic marble samples with negative Eu anomalies (0.15-0.23), declined LREE, flat HREE and lower ΣREE concentration (8.48-11.1 ppm), indicating a close genetic relationship between them. Homogenization temperatures analyses on the fluid inclusions in tremolite yield a minimum temperature 293 °C for the nephrite formation. Nephrites have oxygen and hydrogen isotope compositions in the range from +3.2 to +6.2 per mil and -83.0 to -94.7 per mil, respectively. The corresponding equilibrated fluids have isotope compositions of δ 18O = +3.1 to +6.1 (293 °C). Combined with field observation, there are at least three possible fluid sources: meteoric water, magmatic water and CO 2 derived from decarbonation of dolomite, and a metasomatic and dolomite-related origin is suggested for the Alamas ore body in the Hetian nephrite deposit, Xinjiang, NW China.

  8. 湖相碳酸盐岩烃源岩有机显微组分分类及其岩石学特征——以酒西盆地为例%A petrographic classification of macerals in lacustrine carbonate source rocks and their organic petrological characteristics: A case study on Jiuxi basin, NW China

    Institute of Scientific and Technical Information of China (English)

    涂建琪; 陈建平; 张大江; 程克明; 陈建军; 杨智明

    2012-01-01

    酒西盆地主力烃源岩为下白垩统下沟组和赤金堡组暗色半深湖相-深湖相的白云质泥岩和泥质白云岩,是典型的湖相碳酸盐岩烃源岩.通过对酒西盆地下白垩统二百多块湖相碳酸盐岩烃源岩详细的有机岩石学研究,解剖了湖相碳酸盐岩烃源岩中有机质的赋存形式,揭示了藻纹层为有机质纹层的主要发育形式,其与富泥晶白云石纹层和富粘土纹层构成湖相碳酸盐岩烃源岩特有的“三元式纹层”沉积结构,系统总结了各显微组分的光性、成因、生烃性及分布规律,提出了以全岩和干酪根为基础的湖相碳酸盐岩有机显微组分分类方案,首次鉴定出对酒西盆地油气有贡献的主要生烃组分为腐泥无定形体、腐殖无定形体以及浮游藻类体、孢粉体、壳屑体五种有机显微组分.%The typical lacustrine carbonate source rocks include dark dolomitic mudstone and argillaceous dolomite of Chijinpu ami Xiagou formations of Lower Cretaceous, which represent major petroleum source rocks in Jiuxi basin, NW China. Over 200 samples were selected from Lower Cretaceous lacustrine carbonate source rocks in Jiuxi basin for a detailed organic petrology analysis. Organic laminae has been recognized which is mainly algal laminae and "three-layer" structure is unique for lacustrine carbonate source rocks, which consists of algal laminae, micrite dolomite laminae and clay laminae. A petrographic classification of macerals in lacustrine carbonate source rocks has been suggested on the basis of whole rock and kerogen analysis. The discussion has also been carried out on the origins, the optical properities, hydrocarbon generation potential and geological distribution of macerals in these lacustrine carbonate source rocks. Five major hydrocarbon-generating macerals contributed to petroleum resources are firstly identified which are sapropelic amorphogen, humic amorphogen, alginite, sporopollenite and

  9. Late Pleistocene/Holocene wetland events recorded in southeast Tengger Desert lake sediments, NW China

    Institute of Scientific and Technical Information of China (English)

    D. B. Madsen; CHEN Fahu; Ch. G. Oviatt; ZHU Yan; P. J. Brantingham; R. G. Elston; R. L. Bettinger

    2003-01-01

    The area along the eastern and southeastern margins of the Tengger Desert, NW China, which is sensitive to the summer monsoon variations, was selectedfor studying the environmental conditions surrounding the transition between Paleolithic foragers and Neolithic farmer/pastoral- ists. Short cores were obtained from four lake basins in the southwestern Tengger using a hand-driven piston coring device. Proxies from these cores were supplemented by ra- diocarbon ages obtained from lake sediment cores, shoreline features and spring mound deposits. Together these records provide evidence of millennial-scale climate change events from the Pleistocene-Holocene transition to the present. Lake/wetland events, representing periods of more intensive summer monsoon, occur in the records at ~12.7-11.6, ~10.1, ~9.3, ~8.0, ~5.4, ~1.5, and ~0.8 ka BP. They do suggest that century- to millennial-scale climatic cycles are characteristic of the Holocene in the southeastern Tengger Desert although the chronology must be considered extremely tentative.

  10. An Integrated 3S and Historical Materials Analysis of the Keriya Paleoriver, NW China

    Science.gov (United States)

    Luo, Lei; Wang, Xinyuan; Cai, Heng

    2014-03-01

    Combining analysis of 3S (RS, GIS and GPS) and historical materials (historical records, ancient map and academic and literary writings) allows mapping of the Keriya Paleoriver of Southern Xinjiang, NW China. Keriya Paleoriver, one of the ancient Four Green Corridors which passes through the Taklimakan Desert from south to north in the Tarim Basin, recorded changes of the climate-environment in the ancient Silk Road of the region. According to the archaeological data, historical materials and paleoclimates information, its eco-environment and climate have had great changes since the 1.09Ma B.P., especially during the last 2,000 years, which has led to many famous ancient cities to be abandoned and the route of the ancient Silk Road to be moved southward. Using RS (optical and radar imagery), GIS (mapping and spatial analysis) and GPS (study area investigation), we mapped a major paleodrainage system of Keriya River, which have linked the Kunlun Mountains to the Tienshan Mountains through the Taklimakan Desert, possibly as far back as the early Pleistocene. This study illustrates the capability of the 3S and historical materials, in mapping the Keriya Paleoriver drainage networks and archaeological study on the ancient Silk Road.

  11. Mapping groundwater renewability using age data in the Baiyang alluvial fan, NW China

    Science.gov (United States)

    Huang, Tianming; Pang, Zhonghe; Li, Jie; Xiang, Yong; Zhao, Zhijiang

    2017-01-01

    Groundwater age has been used to map renewability of water resources within four groups: strong, partial, and rare renewability, and non-renewable. The Baiyang alluvial fan in NW China is a representative area for examining groundwater recharge from river infiltration and for mapping groundwater renewability, and it has been investigated using multiple isotopes and water chemistry. Systematic sampling included 52 samples for 2H and 18O analysis and 32 samples for 3H, 13C and 14C analysis. The δ13C compositions remain nearly constant throughout the basin (median -12.7‰) and indicate that carbonate dissolution does not alter 14C age. The initial 14C activity of 80 pmC, obtained by plotting 3H and 14C activity, was used to correct groundwater 14C age. The results show that areas closer to the river consist of younger groundwater ages; this suggests that river infiltration is the main recharge source to the shallow groundwater system. However, at distances far away from the river, groundwater ages become older, i.e., from modern water (less than 60 year) to pre-modern water (from 60 to 1,000 years) and paleowater (more than 1,000 yeas). The four classifications of groundwater renewability have been associated with different age ranges. The area of shallow groundwater with strong renewability accounts for 74% of the total study area. Because recharge condition (river infiltration) controls overall renewability, a groundwater renewability map is of significant importance to the management of groundwater exploitation of this area as well as other arid groundwater basins.

  12. An Eocene-Miocene continuous high resolution rock magnetic record from the sediments in the Xining Basin, NW China: indication for Cenozoic persistent drying driven by global cooling and Tibetan Plateau uplift

    Science.gov (United States)

    Zan, J.; Fang, X.; Appel, E.; Yan, M.; Song, C.

    2013-12-01

    Tibetan Plateau uplift and global cooling have generally been thought to have caused the drying of the Asian inland. But how and when these factors drove the aridification is unknown. The Xining Basin at the NE Tibetan Plateau received continuous Eocene-Miocene fine-grained sediments, providing an excellent opportunity to assess this question. We carried out firstly detailed rock magnetic measurements and diffuse reflectance spectroscopy (DRS) analyses for a well-dated Cenozoic sedimentary record from the Xiejia section in the basin. Magnetic susceptibility (χ) in this section shows a long-term decreasing trend from ~52 Ma to ~25 Ma, well coinciding with global cooling and drying in the region, and an increasing trend since ~25 Ma, which is in contrast to the further progressing aridification of the basin. Thermomagnetic results and DRS-determined hematite contents suggest that the relative content of magnetite and hematite is the main control on the χ values. We argue that the long-term Eocene-Oligocene global cooling increased the drying of the Asian inland, lowering the lake level and exposing a larger area to low temperature oxidation for longer times, thus producing more hematite and leading to the decreasing trend of χ from ~52 Ma to ~25 Ma. An intensive uplift of the NE Tibetan Plateau since ~25 Ma, associated with a change in the sedimentary source, might be responsible for the increase of χ after 25 Ma.

  13. The geostatistical approach for structural and stratigraphic framework analysis of offshore NW Bonaparte Basin, Australia

    Science.gov (United States)

    Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Gaafar, Gamal Ragab; Yusoff, Wan Ismail Wan

    2016-02-01

    Geostatistics or statistical approach is based on the studies of temporal and spatial trend, which depend upon spatial relationships to model known information of variable(s) at unsampled locations. The statistical technique known as kriging was used for petrophycial and facies analysis, which help to assume spatial relationship to model the geological continuity between the known data and the unknown to produce a single best guess of the unknown. Kriging is also known as optimal interpolation technique, which facilitate to generate best linear unbiased estimation of each horizon. The idea is to construct a numerical model of the lithofacies and rock properties that honor available data and further integrate with interpreting seismic sections, techtonostratigraphy chart with sea level curve (short term) and regional tectonics of the study area to find the structural and stratigraphic growth history of the NW Bonaparte Basin. By using kriging technique the models were built which help to estimate different parameters like horizons, facies, and porosities in the study area. The variograms were used to determine for identification of spatial relationship between data which help to find the depositional history of the North West (NW) Bonaparte Basin.

  14. Kashmir Basin Fault and its tectonic significance in NW Himalaya, Jammu and Kashmir, India

    Science.gov (United States)

    Shah, A. A.

    2015-10-01

    The Kashmir Basin Fault is located in the Jammu and Kashmir region of Kashmir Basin in NW Himalaya, India. It is a classic example of an out-of-sequence thrust faulting and is tectonically active as observed from multiple geological evidences. Its geomorphology, structure and lateral extent indicate significant accommodation of stress since long, which is further supported by the absence of a large earthquake in this region. It seems this fault is actively accommodating some portion of the total India-Eurasia convergence, apart from two well-recognised active structures the Medlicott-Wadia Thrust and the Main Frontal Thrust, which are referred in Vassallo et al. (Earth Planet Sci Lett 411:241-252, 2015). This requires its quantification and inclusion into slip distribution scheme of NW Himalaya. Therefore, it should be explored extensively because this internal out-of-sequence thrust could serve major seismic hazard in KB, repeating a situation similar to Muzaffarabad earthquake of Northern Pakistan in 2005.

  15. Dynamic Magma Conduit System Related to the Jinchuan Ni-Cu Sulfide Deposit, NW China

    Institute of Scientific and Technical Information of China (English)

    SONG Xie-yan; CHEN Lie-meng; TIAN Yu-long; XIAO Jia-fei

    2009-01-01

    @@ The Jinchuan Ni-Cu sulfide deposits, NW China, are hosted in small ultramafic intrusions that were emplaced into Paleoproterozoic metamorphic rocks. The ultramafic intrusions were previously thought to be the segments of a single elongate intrusion that was dismembered by late faults into eastern and western portions, each of which have distinct stratigraphic sequences.

  16. An Eocene-Miocene continuous rock magnetic record from the sediments in the Xining Basin, NW China: indication for Cenozoic persistent drying driven by global cooling and Tibetan Plateau uplift

    Science.gov (United States)

    Fang, Xiaomin; Zan, Jinbo; Appel, Erwin; Lu, Yin; Song, Chunhui; Dai, Shuang; Tuo, Shibo

    2015-04-01

    Tibetan Plateau uplift and global cooling have generally been thought to have caused the drying of the Asian inland, but how and when these factors drove the aridification is unknown. The Xining Basin at the NE Tibetan Plateau received continuous Eocene-Miocene fine-grained sediments, providing an excellent opportunity to address this question. Here we present detailed rock magnetic and diffuse reflectance spectroscopy (DRS) analyses for a well-dated Cenozoic sedimentary record from the Xiejia section in the basin. Magnetic susceptibility (χ), saturation magnetization (Ms) and saturation isothermal remanent magnetization (SIRM) in this section show a long-term decreasing trend from ˜52 to ˜25 Ma, well coinciding with global cooling and drying in the region, and an increasing trend since ˜25 Ma, which is in contrast to the further progressing aridification of the basin. Thermomagnetic results and DRS-determined hematite contents suggest that the relative content of magnetite and hematite is the main control on the χ, Ms and SIRM values. We argue that the long-term Eocene-Oligocene global cooling increased the drying of the Asian inland, lowering the lake level and exposing a larger area to low temperature oxidation for longer times, thus producing more hematite and leading to the decreasing trend of magnetic concentration parameters from ˜52 to ˜25 Ma. An intensive uplift of the NE Tibetan Plateau since ˜25 Ma, associated with a change in the sedimentary source, might be responsible for the increase of χ, Ms and SIRM after 25 Ma.

  17. A preliminary study of NW Zhejiang foreland fold and thrust belt in Southeast China

    Institute of Scientific and Technical Information of China (English)

    肖文交; 李继亮; 何海清; 陈海泓

    1997-01-01

    The Upper Permian Dalong Formation (P2d) and Changxing Formation (P2c), and the Lower Tri-assic Zhengtang Formation (Tiz) are of deep-water turbidites. The sedimentary features of the NW Zhejiang are of SE-dipping passive continental margin from the Paleozoic to the early Triassic. Together with the foreland molasse basin during the late Triassic (T3w), the tectonics of the NW Zhejiang is characterised by a tectogenesis which took place in the middle Triassic. From SE to NW, the structural style varies from multi-duplex, antiformal stack to imbricate fans, and then to Jura Mountain-type fold zone with fold-style varying gradually from large-scale tight fold to mid-scale chevron fold, then to cylindrical fold, reviewing a preliminary scenario of foreland fold and thrust belt. The space-distributed structures and the tectonic vergence indicate the significance of deformation in (T1-T3).

  18. 重新划分塔里木盆地塔北隆起的次级构造单元%Redivision of the tectonic units of Tabei Rise in Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    李曰俊; 杨海军; 张光亚; 郑多明; 刘云祥; 赵岩; 李国会; 刘亚雷

    2012-01-01

    塔北隆起位于塔里木盆地北部,是塔里木盆地油气最富集的构造单元之一.其在古生代克拉通内古隆起的基础上,于二叠纪末-三叠纪早期定型为库车周缘前陆盆地的前缘隆起.新生代,其整体沉降,成为埋藏于北塔里木陆内前陆盆地前渊下的一个残余古隆起.目前通用的塔北隆起构造单元划分方案不能准确反映其真实的构造格局.根据最新的研究成果,我们建议重新划分塔北隆起构造单元:(1)取消哈拉哈塘凹陷和草湖凹陷,重新定义轮南低凸起.重新定义的轮南低凸起包括原轮南低凸起、哈拉哈塘凹陷和草湖凹陷北部,是一个下古生界大型鼻状背斜构造,形成于前石炭纪;原草湖凹陷南部划归北部坳陷.(2)以中奥陶统顶面海拔约-6500m的等高线作为塔北隆起的南部边界,该等高线较好地反映了塔北隆起南部的构造轮廓,特别是轮南大型鼻状背斜构造的轮廓.(3)以羊塔1-英买8断裂和英买4-英买1背斜组成的一条较清晰的古生界构造线划分轮台凸起和英买力低凸起.此界线两侧,古生界各反射层存在陡然、明显的落差,岩浆作用、地层发育、构造变形和演化历史存在明显差异.重新划分的塔北隆起包括库尔勒鼻状凸起、轮台凸起、轮南低凸起、英买力低凸起和温宿鼻状凸起五个次级构造单元.本文给出了塔北隆起及其各次级构造单元清晰的定义和范围,并简单论述了其形成演化过程.%In the northern part of Tarim basin, the Tabei Rise is one of the tectonic units richest in oil and gas accumulation. Based on the Paleozoic intra-craton uplift, it developed into the forebulge of Kuqa peripheral foreland basin in terminal Permian-Early Triassic. During Cenozoic it subsided entirely and became a residue of paleo-uplift buried beneath the foredeep of the intracontinental foreland basin in northern Tarim. The existing division of the tectonic units of

  19. Organic matter in deep carbonate rocks of the Tarim Basin, NW China%塔里木盆地深层碳酸盐岩中有机质特征

    Institute of Scientific and Technical Information of China (English)

    周世新; 宋振响; 王保忠; 贾星亮; 李靖

    2011-01-01

    Compositions of free and inclusion organic matter and the individual hydrocarbon isotopic compositions of n-alkanes and isoalkanes were investigated in deep carbonate rocks from the Tacan 1 well of the Tarim Basin.The comparison reveals that there are different evolutional trends for biomarker maturity parameters in different occurrences of organic matter at the high- and over-mature stage.The biomarker thermal maturity parameters of Ts/Tm for C27 hopanes and tricyclics/hopanes ratio can still be used to estimate the maturity of source-rock extracts when Ro is in the range of 1.0%-1.3%.Wherces, these biomarker parameters showed reverse trends and are not useful for maturity assessment when Ro is over 1.3%.The two ratios of C29 sterane isomerization, 205/(205+20R) and ββ/ββ+αα),also showed reverse change trends and can not be used to indicate the level of maturity when Ro is more than 1.1%.Although there are obvious different molecular compositions between free organic matter (chloroform bitumen A) and inclusion organic matter (chloroform bitumen C) in the deep carbonate rocks, the carbon isotopic values of n-alkanes and isoalkanes have similar values for the same samples with two different existence states, which indicates that the organic matters in the two existence states are derived from the same precursor, and their differences in molecular composition characteristics are due to the difference in thermal maturity.%通过对塔里木盆地塔参1井深层碳酸盐岩中游离有机质和包裹有机质组成及正、异构烷烃单体烃碳同位素组成特征的对比研究发现,在高-过成熟演化阶段,不同赋存形式有机质中常用生物标志化合物成熟度参数存在明显不同的响应.R值为1.0%~1.3%时,Ts/Tm和Σ三环萜/Σ藿烷参数仍可用作成熟度指标;当R值大于1.3%时,这两项参数变化趋势发生反转,不能用以表征有机质的热演化程度.C甾烷两项成熟度参数20S/(20S+20R)和

  20. Dolomitization mechanism of Cambrian carbonates in the Bachu area,Tarim Basin, NW China%巴楚地区寒武系碳酸盐岩白云石化机制

    Institute of Scientific and Technical Information of China (English)

    周波; 李明; 段书府; 朱长见; 邬光辉; 曾昌民; 高力

    2012-01-01

    Geochemical characteristics of the Cambrian carbonates are studied through systematic sampling in the Bachu area of the Tarim Basin. The dolomitization mechanisms are compared and analyzed of the dolomites above and below salt beds and limestone between the salt beds. The δ 18O values of dolomites in the limestone between salt beds are larger than -6%o, the δ 13C values are normally larger than -l%o, the 87 Sr/86 Sr values are smaller than ancient sea water plus Mn and Na element enrichment. All these features suggest that the dolomites are developed due to early sabakha dolomitization. For the dominantly medium- and coarse-grained dolomites above the uppper salt bed, the δ 13C values of samples are lower than zero, the δ 13 O values are normally -9%o-0, the 87Sr/86Sr values are close to ancient sea water. These features show that the dolomites are developed in a shallow burial environment. For the dominantly powdered and fine dolomites below the lower salt bed, the δ 13C values of samples are larger than zero, the δ 18O values are normally lower than zero, the 87 Sr/86Sr values are larger than the above mentioned dolomites, plus Fe and Sr element enrichment. These features indicate that the dolomites are developed within an evaporate environment on a restricted platform, and they are of penetration reflux dolomitization and affected by the deep burial hyperthermal environment later.%通过系统取样进行地球化学分析,研究塔里木盆地巴楚地区寒武系碳酸盐岩地球化学特征,在此基础上对盐上白云岩、盐间灰岩及盐下白云岩的白云石化成因进行对比研究.盐间灰岩中的白云石δ18O值大于-6‰,δ13C值一般大于-1‰,87Sr/86Sr值略低于古海水,Mn和Na元素富集,表明白云石化作用发生在沉积早期,系萨布哈成因;盐上白云岩以中—粗晶白云岩为主,δ13C值偏负,δ18O值偏负但均大于-9‰,87Sr/86Sr值趋同于古海水,反映形成于浅埋藏环境;盐下白云岩

  1. Middle Miocene coralline algal facies from the NW Transylvanian Basin (Romania)

    Science.gov (United States)

    Chelaru, Ramona; Bucur, Ioan I.; Sǎsǎran, Emanoil; Bǎlc, Ramona; Tǎmas, Tudor

    2016-04-01

    s\\varan E., Bucur I.I., Bǎlc R., Tǎmas T. & Beldean C. (2011). Carbonate facies with rhodoliths from Vǎlenii Șomcutei (NW Transylvanian Basin). In: Bucur I.I. & Sǎs\\varan E. (eds) - 10th International Symposium on Fossil Algae, Cluj-Napoca, Abstract Book, p. 16. [2] Szakács A., Pécskay Z., Silye L., Balogh K., Vlad D. & Fülöp A. (2012). On the age of the Def Tuff, Transylvanian Basin (Romania). Geologica Carpathica, vol. 63(2), p. 139-148.

  2. 塔里木盆地库车坳陷致密砂岩气藏成因类型%Genetic Types of the Tight Sandstone Gas Reservoirs in the Kuqa Depression, Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    李卓; 姜振学; 庞雄奇; 李峰; 张宝收

    2013-01-01

    To further understand the genetic types of the tight sandstone gas reservoirs in Kuqa depression, the core from tight sandstone gas reservoirs is sampled to carry out the analysis on hydrocarbon charge history and porosity evolutioa The hydrocarbon charge history is investigated by analyzing the fluid inclusion petrography, and microther mometry and the porosity evolution is restored by using the model of deposition-structure -diagenesis. Combining with gas-water relationship and distribution of tight sandstone gas reservoirs. There are two charge events in the YN2 Jurassic tight sandstone reservoir, with the one of oil charge during 23-12 Ma, and the other gas charge during 5-0 Ma. The reservoir porosity dropped to less than 12% and became tight during the period of 12-8 Ma Two charge events have been recorded in the DN2 Paleogene tight sandstone reservoir; the former is oil charge during 23-12 Ma, and the latter is the gas charge during 5 - 0 Ma. The reservoir porosity dropped to less than 12% during the period of 2-0 Ma and became tight later. Two genetic types of tight sandstone gas reservoirs have been confirmed. The YN2 Jurassic tight sandstone reservoir is of the genetic type of "tight deep basin gas reservoir" with the accumulation process of gas charge after the reservoir tightened and the DN2 Paleogene tight sandstone reservoir is defined as "tight conventional gas reservoir" with the accumulation process of gas charge before the reservoir tightened. This study is of significance for further exploration and exploitation of tight sandstone gas in Kuqa depressioa.%为深化对库车坳陷致密砂岩气藏成因类型的认识,采集致密砂岩储层岩样,开展了油气充注史和孔隙度演化史研究.通过流体包裹体岩相学和显微测温厘定了油气充注史,利用沉积-构造-成岩一体化模型恢复了储层孔隙度演化史,根据两者的先后关系,划分了致密砂岩气藏的成因类型.结果表明,依南2侏罗系气藏

  3. Evolution of the central Walvis Basin / offshore NW Namibia - balancing onshore erosion and offshore sedimentation

    Science.gov (United States)

    Henk, A.; Kukulus, M.; Junker, R.

    2003-04-01

    Rifting and break-up of Gondwana in the Late Jurassic / Early Cretaceous led to formation of the South Atlantic. One of the associated passive margins, the Walvis Basin in NW Namibia, is used as a case study to investigate the mass and process balances which link uplift and erosion onshore to contemporaneous subsidence and sedimentation offshore. One of the main objectives of the project is to gain quantitative insights into the feedback mechanisms between surface processes and lithospheric processes during passive margin evolution. Modeling concentrates on a traverse across the central Walvis Basin and adjacent onshore areas. Mass balancing requires a reconstruction of the denudation history and the volumes eroded onshore as well as a quantification of the contemporaneous sedimentary record preserved offshore. In the offshore parts of the study area, seismic sections and well data are available to constrain the post-rift evolution of the Walvis basin. However, as none of the exploration wells has yet reached syn-rift deposits, the early margin evolution has to remain speculative. In the onshore part of the traverse, field evidence and published apatite fission track data are used to reconstruct the erosion history. Comparison of the eroded and deposited volumes and masses, respectively, reveals a misfit of about 50 %, i.e. only half of the sediments observed offshore can be attributed to nearby source areas onshore. This result is supported by provenance analysis on cuttings from an offshore well which indicate that a substantial part of the detritus was derived from sources to the south and transported to the central Walvis Basin by coast-parallel currents. Sediment supply rates derived from reconstruction of the onshore erosion history and subsidence rates based on lithospheric cooling models together with global sea level changes are then used to model quantitatively deposition and stratigraphic architectures of the post-rift succession in the central Walvis

  4. Major Fault Systems and Mountain Building Processes in the Tibetan Foreland and Beishan Region, NW China

    Science.gov (United States)

    Cunningham, D.; Zhang, J.

    2012-04-01

    strain on either side. The rigid Tarim block appears to be the major rheological control on the limited northward growth of the plateau in the Sanweishan-Nanjieshan region. Basement rocks in the Beishan region record several major collisional suturing events associated with amalgamation of the Central Asian Orogenic belt. These events are expressed in a remote region north of Liuyuan by kilometre-scale refolded folds of Permian clastic sediments that are spectacular when seen on satellite imagery. The folds were ground-verified during summer, 2009 and sedimentary way-up criteria, cleavage-bedding relations and folded quartz veins were also documented to further constrain the fold geometries and deformational history. Detailed mapping of key areas and structural data analysis reveal that the folds initially formed by Late Permian NNE-SSW directed shortening associated with collisional suturing along the western extent of the Solonker Suture. Subsequent dextral transpression along a major terrane boundary immediately south of the Permian basin generated NW-SE shortening and km-scale type-2 refolds. During all Palaeozoic terrane amalgamation events, the Beishan crustal block was located between the rigid Tarim and North China Precambrian cratons, and more recently between the modern intracontinental deforming belts in northern Tibet and the Gobi Altai. Thus the Beishan's unique position within Asia has led to a particularly complex polydeformational history involving repeated crustal reactivation by both near-field and far-field stresses associated with Late Palaeozoic-Recent collisional events.

  5. Evidence for active tilting of the NW-German Basin from correlations between fluvial landscape and geological subground

    Science.gov (United States)

    Szeder, Thore; Sirocko, Frank

    2005-02-01

    The catchment basin of the River Hunte (Lower Saxony, NW-German Basin) was studied on a mesoscale (length of ~90 km) to investigate the influence of the geological subground on modern morphology. A Geo Information System (GIS) was used to calculate linear correlation coefficients between the depth of geological strata (Base Zechstein to Base Quaternary) and the height of the modern landscape (Holocene Alluvial Plain, Lower Weichselian Terrace, catchment basin and watershed). High linear correlation coefficients between the Base of Tertiary and the height of the modern topography (catchment basin [r2=0.87], Lower Weichselian Terrace [r2=0.95] and Holocene Alluvial Plain [r2=0.95]) indicate control of the modern topography by the depth of the geological subsurface via tilting of the entire basin. Most likely northward tilting of the NW-German Basin forces the River Hunte to flow in a northerly direction by relative uplift of the hinterland (Wiehengebirge, Rhenish Massif) and subsidence of the North Sea area.

  6. REVISION AND RE-DOCUMENTATION OF M. AIROLDI'S SPECIES OF ARCHAEOLITHOTHAMNIUM FROM THE TERTIARY PIEDMONT BASIN (NW ITALY

    Directory of Open Access Journals (Sweden)

    GRAZIA VANNUCCI

    2000-07-01

    Full Text Available Airoldi (1930, 1932 described twenty-three fossil Corallinales (Rhodophyta from the Oligocene of the Tertiary Piedmont Basin (NW Italy, containing thirteen new species. In this paper Archaeolithothamnium praeerithraeum Airoldi 1932 and Archaeolithothamnium statiellense Airoldi 1932 are re-documented and re-described. The features observable in the sporangial compartments allowed to attribute both species to the genus Sporolithon. 

  7. Jurassic extension and Cenozoic inversion tectonics in the Asturian Basin, NW Iberian Peninsula: 3D structural model and kinematic evolution

    Science.gov (United States)

    Uzkeda, Hodei; Bulnes, Mayte; Poblet, Josep; García-Ramos, José Carlos; Piñuela, Laura

    2016-09-01

    We constructed a geological map, a 3D model and cross-sections, carried out a structural analysis, determined the stress fields and tectonic transport vectors, restored a cross section and performed a subsidence analysis to unravel the kinematic evolution of the NE emerged portion of the Asturian Basin (NW Iberian Peninsula), where Jurassic rocks crop out. The major folds run NW-SE, normal faults exhibit three dominant orientations: NW-SE, NE-SW and E-W, and thrusts display E-W strikes. After Upper Triassic-Lower Jurassic thermal subsidence, Middle Jurassic doming occurred, accompanied by normal faulting, high heat flow and basin uplift, followed by Upper Jurassic high-rate basin subsidence. Another extensional event, possibly during Late Jurassic-Early Cretaceous, caused an increment in the normal faults displacement. A contractional event, probably of Cenozoic age, led to selective and irregularly distributed buttressing and fault reactivation as reverse or strike-slip faults, and folding and/or offset of some previous faults by new generation folds and thrusts. The Middle Jurassic event could be a precursor of the Bay of Biscay and North Atlantic opening that occurred from Late Jurassic to Early Cretaceous, whereas the Cenozoic event would be responsible for the Pyrenean and Cantabrian ranges and the partial closure of the Bay of Biscay.

  8. Isotopic and magnetic provenance characterization of distal IRD in the Galicia Interior Basin (NW Iberia)

    Science.gov (United States)

    Plaza-Morlote, Maider; Rey, Daniel; Francisco Santos, Jose; Ribeiro, Sara; Bernabeu, Ana; Mohamed, Kais; Heslop, David; Rubio, Belén; Martins, Virginia

    2016-04-01

    The sediments of the Galicia Interior Basin in NW Iberia Margin are of particular palaeoclimatic interest as they are located at the boundary where the climatic oscillations of the glacial interval were interrupted by extreme events such as Heinrich events. These events are well characterized in Northern North Atlantic areas, but little is known about their occurrence beyond the Ruddiman belt. This study presents a combined environmagnetic and geochemical approach to the provenance and characterization of distal ice-rafted detritus (IRD) that occurred during the last glacial period in core CI12PC3 from the Galicia Interior Basin. The last six Heinrich Layers were identified by their magneto-mineralogical and geochemical properties. Their Sr and Nd isotopic signatures indicated that the Laurentide Ice Sheet was the major source for HL1, HL2, HL4 and HL5. However, the European ice sheets also influenced the initial development stages of HL1, HL2, HL4. HL3, HL6 and partially HL1, HL2 and HL4 were influenced by more juvenile provinces, such as Iceland/Faroes sheets and/or by the Fram Strait/East Greenland nearby areas. Separate provenance analyses of the coarse and fine fractions in the studied Heinrich Layers also indicated that IRDs and glacial flour sources might not always be the same. Our results shed unequivocal evidence that Canadian-sourced distal IRD are preceded by European-sourced IRD, at least from the H4. In our view, LIS and EIS instabilities registered in the Iberian Margin respond to the same climate forcing at different velocities.

  9. Deformation and fluid flow in the Huab Basin and Etendeka Plateau, NW Namibia

    Science.gov (United States)

    Salomon, Eric; Koehn, Daniel; Passchier, Cees; Chung, Peter; Häger, Tobias; Salvona, Aron; Davis, Jennifer

    2016-07-01

    The Lower Cretaceous Twyfelfontein sandstone formation in the Huab Basin in NW Namibia shows the effects of volcanic activity on a potential reservoir rock. The formation was covered by the Paraná-Etendeka Large Igneous Province shortly before or during the onset of South-Atlantic rifting. Deformation bands found in the sandstone trend mostly parallel to the continental passive margin and must have formed during the extrusion of the overlying volcanic rocks, indicating that their formation is related to South-Atlantic rifting. 2D-image porosity analysis of deformation bands reveals significant porosity reduction from host rock to band of up to 70%. Cementation of the sandstone, linked to advective hydrothermal flow during volcanic activity, contributes an equal amount to porosity reduction from host rock to band when compared to initial grain crushing. Veins within the basaltic cover provide evidence for hot fluid percolation, indicated by spallation of wall rock and colloform quartz growth, and for a later low-temperature fluid circulation at low pressures indicated by stilbite growth sealing cavities. Sandstone samples and veins in the overlying volcanic rocks show that diagenesis of the Twyfelfontein sandstone is linked to Atlantic rifting and was affected by both hydrothermal and low-thermal fluid circulation.

  10. Towards a climate impact assessment of the Tarim River, NW China: integrated hydrological modelling using SWIM

    Science.gov (United States)

    Wortmann, Michel

    2014-05-01

    The Tarim River is the principle water source of the Xinjiang Uyghur Autonomous Region, NW China and the country's largest endorheic river, terminating in the Taklamakan desert. The vast majority of discharge is generated in the glaciated mountain ranges to the north (Tian Shan), south (Kunlun Shan/Tibetan Plateau) and west (Pamir Mountains) of the Taklamakan desert. The main water user is the intensive irrigation agriculture for mostly cotton and fruit production in linear river oases of the middle and lower reaches as well as a population of 10 Mil. people. Over the past 40 years, an increase in river discharge was reported, assumed to be caused by enhanced glacier melt due to a warming climate. Rapid population growth and economic development have led to a significant expansion of area under irrigation, resulting in water shortages for downstream users and the floodplain vegetation. Water resource planning and management of the Tarim require integrated assessment tools to examine changes under future climate change, land use and irrigation scenarios. The development of such tools, however, is challenged by sparse climate and discharge data as well as available data on water abstractions and diversions. The semi-distributed, process-based hydrological model SWIM (Soil and Water Integrated Model) was implemented for the headwater and middle reaches that generate over 90% of discharge, including the Aksu, Hotan and Yarkant rivers. It includes the representation of snow and glacier melt as well as irrigation abstractions. Once calibrated and validated to river discharge, the model is used to analyse future climate scenarios provided by one physically-based and one statistical regional climate model (RCM). Preliminary results of the model calibration and validation indicate that SWIM is able simulate river discharge adequately, despite poor data conditions. Snow and glacier melt account for the largest share in river discharge. The modelling results will devise

  11. Mountain pastures of Qilian Shan: plant communities, grazing impact and degradation status (Gansu province, NW China)

    Science.gov (United States)

    Baranova, Alina; Schickhoff, Udo; Shunli, Wang; Ming, Jin

    2015-04-01

    Qilian Mountains are the water source region for the low arid reaches of HeiHe river basin (Gansu province, NW China). Due to overstocking and overgrazing during the last decades adverse ecological ef¬fects, in particular on soil properties and hydrological cycle, are to be expected in growing land areas. Vegetation cover is very important to prevent erosion process and to sustain stable subsurface runoff and ground water flow. The aim of this research is to identify plant communities, detecting grazing-induced and spatially differentiated changes in vegetation patterns, and to evaluate status of pasture land degradation.The study area is located in the spring/autumn pasture area of South Qilian Mountains between 2600-3600 m a.s.l., covering five main vegetation types: spruce forest, alpine shrubland, shrubby grassland, mountain grassland, degraded mountain grassland. In order to analyze gradual changes in vegetation patterns along altitudinal and grazing gradients and to classify related plant communities, quantitative and qualitative relevé data were collected (coverage, species composition, abundance of unpalatable plants, plant functional types, etc.). Vegetation was classified using hierarchical cluster analyses. Indirect Detrended Correspondence Analysis (DCA) was used to analyze variation in relationships between vegetation, environmental factors, and grazing impact. According to DCA results, distribution of the plant communities was strongly affected by altitude and exposition. Grassland floristic gradients showed greater dependence on grazing impact, which correlated contrarily with soil organic content, soil moisture and pH. Highest numbers of species richness and alpha diversity were detected in alpine shrubland vegetation type. Comparing the monitoring data for the recent nine years, a trend of deterioration, species successions and shift in dominant species becomes obvious. Species indicating degrading site environmental conditions were identified

  12. Significance of native arsenic in the Baogutu gold deposit, western Junggar, Xinjiang, NW China

    Institute of Scientific and Technical Information of China (English)

    AN Fang; ZHU YongFeng

    2009-01-01

    Native arsenic together with comb quartz and stibnite is found in the Baogutu gold deposit, western Junggar (Xinjiang), NW China. It is anhedral with various grain size ( con-centration of hydrothermal fluid decrease obviously, whereas the As concentration increases. Coexis-tence with native arsenic of electrum and its contents of 0.5 wt%-1.3 wt% As suggest that As is im-portant to transport Au when S concentration decrease in hydrothermal fluid. Crystallization of native arsenic induced the deposition of electrum and consequently the formation of the Baogutu gold deposit.

  13. Cyclone trends constrain monsoon variability during Late Oligocene sea level highstands (Kachchh Basin, NW India

    Directory of Open Access Journals (Sweden)

    M. Reuter

    2013-01-01

    Full Text Available Important concerns about the consequences of climate change for India are the potential impact on tropical cyclones and the monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin as an indicator of tropical cyclone activity along the NW Indian coast during the Late Oligocene warming period (~27–24 Ma. Direct proxies providing information about the atmospheric circulation dynamics over the Indian subcontinent at this time are important since it corresponds to a major climate reorganization in Asia that ends up with the establishment of the modern Asian monsoon system in the Early Miocene. The vast shell concentrations comprise a mixture of parautochthonous and allochthonous assemblages indicating storm-generated sediment transport from deep to shallow water during third-order sea level highstands. Three distinct skeletal assemblages were distinguished each recording a relative storm wave base depth. (1 A shallow storm wave base is shown by nearshore mollusks, corals and Clypeaster echinoids; (2 an intermediate storm wave base depth is indicated by lepidocyclind foraminifers, Eupatagus echinoids and corallinaceans; and (3 a deep storm wave base is represented by an Amussiopecten–Schizaster echinoid assemblage. Vertical changes in these skeletal associations give evidence of gradually increasing tropical cyclone intensity in line with third-order sea level rise. The intensity of cyclones over the Arabian Sea is primarily linked to the strength of the Indian monsoon. Therefore and since the topographic boundary conditions for the Indian monsoon already existed in the Late Oligocene, the longer-term cyclone trends were interpreted to reflect monsoon variability during the initiation of the Asian monsoon system. Our results imply an active monsoon over the Eastern Tethys at ~26 Ma followed by a period of monsoon weakening during the peak of the Late Oligocene

  14. Cyclone trends constrain monsoon variability during late Oligocene sea level highstands (Kachchh Basin, NW India)

    Science.gov (United States)

    Reuter, M.; Piller, W. E.; Harzhauser, M.; Kroh, A.

    2013-09-01

    Climate change has an unknown impact on tropical cyclones and the Asian monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin) as a recorder of tropical cyclone activity along the NW Indian coast during the late Oligocene warming period (~ 27-24 Ma). Proxy data providing information about the atmospheric circulation dynamics over the Indian subcontinent at this time are important since it corresponds to a major climate reorganization in Asia that ends up with the establishment of the modern Asian monsoon system at the Oligocene-Miocene boundary. The vast shell concentrations are comprised of a mixture of parautochthonous and allochthonous assemblages indicating storm-generated sediment transport from deeper to shallow water during third-order sea level highstands. Three distinct skeletal assemblages were distinguished, each recording a relative storm wave base. (1) A shallow storm wave base is shown by nearshore molluscs, reef corals and Clypeaster echinoids; (2) an intermediate storm wave base depth is indicated by lepidocyclinid foraminifers, Eupatagus echinoids and corallinacean algae; and (3) a deep storm wave base is represented by an Amussiopecten bivalve-Schizaster echinoid assemblage. These wave base depth estimates were used for the reconstruction of long-term tropical storm intensity during the late Oligocene. The development and intensification of cyclones over the recent Arabian Sea is primarily limited by the atmospheric monsoon circulation and strength of the associated vertical wind shear. Therefore, since the topographic boundary conditions for the Indian monsoon already existed in the late Oligocene, the reconstructed long-term cyclone trends were interpreted to reflect monsoon variability during the initiation of the Asian monsoon system. Our results imply an active monsoon over the Eastern Tethys at ~ 26 Ma followed by a period of monsoon weakening during the peak of the late

  15. Cyclone trends constrain monsoon variability during late Oligocene sea level highstands (Kachchh Basin, NW India

    Directory of Open Access Journals (Sweden)

    M. Reuter

    2013-09-01

    Full Text Available Climate change has an unknown impact on tropical cyclones and the Asian monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin as a recorder of tropical cyclone activity along the NW Indian coast during the late Oligocene warming period (~ 27–24 Ma. Proxy data providing information about the atmospheric circulation dynamics over the Indian subcontinent at this time are important since it corresponds to a major climate reorganization in Asia that ends up with the establishment of the modern Asian monsoon system at the Oligocene–Miocene boundary. The vast shell concentrations are comprised of a mixture of parautochthonous and allochthonous assemblages indicating storm-generated sediment transport from deeper to shallow water during third-order sea level highstands. Three distinct skeletal assemblages were distinguished, each recording a relative storm wave base. (1 A shallow storm wave base is shown by nearshore molluscs, reef corals and Clypeaster echinoids; (2 an intermediate storm wave base depth is indicated by lepidocyclinid foraminifers, Eupatagus echinoids and corallinacean algae; and (3 a deep storm wave base is represented by an Amussiopecten bivalve-Schizaster echinoid assemblage. These wave base depth estimates were used for the reconstruction of long-term tropical storm intensity during the late Oligocene. The development and intensification of cyclones over the recent Arabian Sea is primarily limited by the atmospheric monsoon circulation and strength of the associated vertical wind shear. Therefore, since the topographic boundary conditions for the Indian monsoon already existed in the late Oligocene, the reconstructed long-term cyclone trends were interpreted to reflect monsoon variability during the initiation of the Asian monsoon system. Our results imply an active monsoon over the Eastern Tethys at ~ 26 Ma followed by a period of monsoon weakening during the

  16. Formation and syn-rifting process of the Wan'an Basin,South China Sea

    Institute of Scientific and Technical Information of China (English)

    LU Caili; YAO Yongjian; WU Shiguo; DONG Dongdong

    2013-01-01

    Based on seismic and drilling data,we calculated tectonic subsidence amounts and rates of the Wan'an Basin by backstripping.The genetic mechanism and syn-rifting process of the basin were analyzed in combination with the regional geological setting.The results reveal that the basin syn-rifted in the Eocene and early Miocene under the control of the dextral strike-slip Wan'an Fault Zone.The transtensional/extentional stresses along this fault zone may be attributed to seafloor spreading of the South China Sea (SCS) in multiple episodes.Extensive basal faults and some small initial rifts in the early Paleogene can be related to southeastward extrusion and clockwise rotation of the Indochina Block.During the Oligocene,the nearly N-S directed spreading of the SCS derived the transtensional stresses in a roughly NW-SE orientation.The basin subsided rapidly in the middle and north to form two major subsidence centers.In the early Miocene,the SCS spread again in a nearly NW-SE direction,resulting in rapid subsidence in the southern basin continuous extending until the period ~ 16.3 Ma.

  17. Petroleum in the Junggar basin, northwestern China

    Science.gov (United States)

    Taner, Irfan; Kamen-Kaye, Maurice; Meyerhoff, Arthur A.

    The Junggar basin occupies a large triangular area of some 130 000 km 2 in northwestern China. Situated between the Altay Shan (Altay Range) on the northeast and the Tian Shan (Tian Range) on the southwest, and between lesser ranges around the remainder of its periphery, the Junggar basin is completely intermontane. Its history as a basin began in the Permian, and continued as various uplifts and downwarps evolved. Through the Paleozoic the characteristics of the Junggar basin area were largely geosynclinal and marine. Its post-Permian development took place exclusively in continental regimes. Inhabitants of the Junggar basin have known and utilized its numerous oil and asphalt seeps and its spectacular spreads of asphalt for more than 2000 years, especially in the Karamay-Urho thrust belt near the northwestern rim. The first discovery of oil in the modern sense came at Dushanzi, one of the steeply folded anticlines of theÜrümqi foredeep near the southern rim. The first shallow oil in the Karamay-Urho thrust belt came in 1937, followed by commercial production in the Karamay field in 1955. Output continued to be modest until wells were drilled through local thrusts and reverse faults in the early 1980s. By 1985, cumulative production of the Karamay group of fields had reached 42,000,000 t (metric tonnes) (306,000,000 bbl), with a calculated minimum ultimate recovery of 280,000,000 t (2 billion bbl). Principal production comes from Permian and Triassic strata in continental facies. Apart from marine Mid and Upper Carboniferous strata, source rocks occur mainly in fine-grained lacustrine detrital beds of the Permian, the Triassic, the Jurassic and the Tertiary. Several uplifts and downwarps elsewhere in the Junggar basin remain to be drilled comprehensively. Results from such drilling may enhance the very important position that the Junggar already has attained in the hierarchy of China's onshore basins.

  18. REVISION AND RE-DOCUMENTATION OF M. AIROLDI’S SPECIES OF MESOPHYLLUM FROM THE TERTIARY PIEDMONT BASIN (NW ITALY

    Directory of Open Access Journals (Sweden)

    DANIELA BASSO

    1998-03-01

    Full Text Available Airoldi (1930, 1932 described twenty-three fossil Corallinales (Rhodophyta from the Oligocene of the Tertiary Piedmont Basin (NW Italy, including thirteen new species. In this paper Mesophyllum fructiferum Airoldi 1932 and Mesophyllum obsitum Airoldi 1932 are re-documented and re-described. The presence of cell fusions, multiporate conceptacles and a ventral core of cell filaments passing from coaxial to non-coaxial confirm that both species belong to the genus Mesophyllum.   SHORT NOTES  

  19. A large Middle Pleistocene freshwater to oligohaline lake in the contemporary hyperarid Qaidam Basin (China)

    Institute of Scientific and Technical Information of China (English)

    Steffen Mischke; Ulrike Herzschuh; Naida Sun; Zizhen Qiao; Zhencheng Sun

    2006-01-01

    @@ The Qaidam Basin (NW China) at the northern margin of the Tibetan Plateau is one of the driest places on Earth with mean annual precipitation not exceeding 25mm in the western central part. Flat salt plains and wind-shaped hills characterise the bare ground over thousands of square kilometres. In contrast to presentday conditions, remnants of ancient shorelines in high positions identified by Chen and Bowler (1986) and Hovermann and Süssenberger (1986) about 20 years ago herald of a former large lake but were not investigated further till now.

  20. 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.

  1. 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.

  2. Tectonic and Sedimentary Response of the Huangshan Basin to Paleo-Pacific Subduction undernearth Southeast China

    Science.gov (United States)

    Xu, X.; Tang, S.; Lin, S.

    2015-12-01

    The subduction of the Paleo-Pacific Plate predominated the Late Mesozoic tectonic evolution of southeast China. This process is well documented by Jurassic-Cretaceous deposition and structural deformation. Zircon U-Pb ages of volcano-sedimentary rocks and fault-slip data of brittle faults were investigated in the Huangshan Basin. Detrital zircon U-Pb ages show that the provenances of the Huangshan Basin changed during Late Jurassic to Early Cretaceous. The source region of Early and Middle Jurassic sediments is mainly the Wuyishan domain to the southeast. But the Early Cretaceous clastic rocks are derived from the Jiangnan domain to the north. The inversions of fault-slip data show that paleostress fields also changed during Late Jurassic to Early Cretaceous. The strike-slip regime with nearly E-W compression and N-S extension predominated in the late Middle Jurassic whereas intense NW-SE-striking extensional one during Early Cretaceous. Moreover, geochemistry and zircon U-Pb ages of Late Jurassic (156~152 Ma) and Early Cretaceous (~130 Ma) felsic volcanic rocks in the Huangshan Basin also argue for a tectonic event occurred during Late Jurassic to Early Cretaceous. Above results imply that the tectonic background of southeast China changed from the initial subduction of the Paleo-Pacific plate during the Early and Middle Jurassic into subsequence back-arc extension in the Early Cretaceous. The paleostress field then changed into the strike-slip regime with N-S compression and E-W extension during late Early Cretaceous, which is caused by the collision between the Philippine and South China blocks. And after that, a weak and short-lived N-S extension was replaced by the strike-slip regime with NW-SE compression and NE-SW extension. Meanwhile, the South China continental margin also changed from an Andean-type to a Western Pacific-type plate boundary in early Late Cretaceous.

  3. Petroleum Discoveries and Exploration Prospect in China's Major Petroliferous Basins

    Institute of Scientific and Technical Information of China (English)

    Zhou Qingfan

    2008-01-01

    @@ Up to now, there are 29 oil-and gas-bearing basins with recoverable oil and gas reserves in China. However,most of the reserves were mainly discovered in parts of the 29 basins, which played an important role in China's petroleum exploration and development.

  4. 塔里木盆地东北缘敦煌群的形成和演化:锆石U-Pb年代学和Lu-Hf同位素证据%Evolution and formation of the Dunhuang Group in NE Tarim basin, NW China: Evidence from detrital-zircon geochronology and Hf isotope

    Institute of Scientific and Technical Information of China (English)

    孟繁聪; 张建新; 相振群; 于胜尧; 李金平

    2011-01-01

    Dunhuang Group, which occurred in NW China.

  5. Structural differences between the western and eastern Qiongdongnan Basin: evidence of Indochina block extrusion and South China Sea seafloor spreading

    Science.gov (United States)

    Zhang, Cuimei; Wang, Zhenfeng; Sun, Zhipeng; Sun, Zhen; Liu, Jianbao; Wang, Zhangwen

    2013-12-01

    Located at the intersection between a NW-trending slip system and NE-trending rift system in the northern South China Sea, the Qiongdongnan Basin provides key clues for us to understand the proposed extrusion of the Indochina Block along with Red River Fault Zone and extensional margins. In this paper we for the first time systematically reveal the striking structural differences between the western and eastern sector of the Qiongdongnan Basin. Influenced by the NW-trending slip faults, the western Qiongdongnan Basin developed E-W-trending faults, and was subsequently inverted at 30-21 Ma. The eastern sector was dominated by faults with NE orientation before 30 Ma, and thereafter with various orientations from NE, to EW and NW during the period 30-21 Ma; rifting display composite symmetric graben instead of the composite half graben or asymmetric graben in the west. The deep and thermal structures in turn are invoked to account for such deformation differences. The lithosphere of the eastern Qiongdongnan Basin is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed and the faults varied with the basal plate boundary. However, the Southern and Northern Uplift area and middle of the central depression is located on normal lithosphere and formed half grabens or simple grabens. The lithosphere in the western sector is transitional from very hot to normal. Eventually, the Paleogene tectonic development of the Qiongdongnan Basin may be summarized into three stages with dominating influences, the retreat of the West Pacific subduction zone (44-36 Ma), slow Indochina block extrusion together with slab-pull of the Proto-South China Sea (36-30 Ma), rapid Indochina block extrusion together with the South China Sea seafloor spreading (30-21 Ma).

  6. Evolution of Çan-Etili (Çanakkale-NW Turkey) lignite basin:Sedimentology, petrology, palynology and lignite characterization

    Institute of Scientific and Technical Information of China (English)

    Mustafa Bozcu; Funda Akgün; Gülbin Gürdal; Ayşe Bozcu; Sevinç Kapan Yeşilyurt; Öznur Karaca; M. Serkan Akkiraz

    2015-01-01

    abstract This study examines the development and sedimentology of Çan-Etili lignite basin in Biga Peninsula (NW Turkey) along with the palynologic and petrographic properties of the coals in this region. The Çan-Etili lignite basin discordantly overlies Oligocene-aged Çan volcanics. The basin consists of caldera type sedimentation developed by the combined effects of volcanism and tectonics. The volcanic rocks forming the basement of the basin consist of andesitic, dacitic and basaltic lava flows as well as agglomerates, tuff and silicified tuffs, and kaolin which is their alteration product. The basement volcanic rocks cooled from high potassium and calc-alkaline magma. The trace element geochemistry of different rocks within the volcanics reveals that they are from a volcanic arc. The Çan Formation contains lignites and consists of 6 lithofacies representing alluvial, fluvial, marsh and lacustrine environments. These lithofacies are the lower volcanogenic conglomerate, the claystone, the lignite, the laminated organic claystone, the tuff intercalated sandstone–siltstone and the upper volcanogenic conglomerate. The lignite in the basin is limnic and is formed in a non-fluvial marsh and marsh-lake environment. An abundant percentage of vegetation (Engelhardia, Sapotaceae, Cyrillaceae) is compatible with temperate and subtropical climatic conditions in the basin during sedimentation of lignite.The coals of Çan-Etili basin are humic with high sulfur content (6–6.5%average) mostly containing huminite compounds belonging to the class of lignite-low bituminous (C-A) coal. Their coalification rank is between 0.38%and 0.56%Ro. The coals are formed in limnic-limnotelmatic marsh zones based on their microlithotype components. The inorganic components of the coal mostly consist of pyrite and clay. The trace elements, As, Th, U and V, are higher than international coal standards. The coal quality is adversely affected by high sulfur content and sulfur driven trace

  7. Thermal evolution and shale gas potential estimation of the Wealden and Posidonia Shale in NW-Germany and the Netherlands : a 3D basin modelling study

    NARCIS (Netherlands)

    Bruns, B.; Littke, R.; Gasparik, M.; van Wees, J.-D.; Nelskamp, S.

    2016-01-01

    Sedimentary basins in NW-Germany and the Netherlands represent potential targets for shale gas exploration in Europe due to the presence of Cretaceous (Wealden) and Jurassic (Posidonia) marlstones/shales as well as various Carboniferous black shales. In order to assess the regional shale gas prospec

  8. Analysing diagenetic effects of flood basalts on sedimentary basins during Gondwanan break-up: case studies from NW Namibia.

    Science.gov (United States)

    Thompson, G. A.; Jerram, D. A.; Harris, C.; Pearson, D. G.

    2003-04-01

    ABSTRACT The eruption of large volumes of lava associated with the break-up and dispersal of the Gondwana Supercontinent is a phenomenon that has been well documented in literature. The Etendeka Flood Basalt Province of NW Namibia is correlated with the Paraná Flood Basalt Province of South America and was extruded between 139Ma for the earliest flows and 130Ma for the most recent. The passive, inflated pahoehoe lava flows have preserved bedforms within sand dunes found in the Huab Basin without significant deformation. This allows the internal structures of the palaeo-dunes to be analysed with great accuracy; a phenomenon rarely seen within the geological record. The sediments directly beneath, and interbedded with, the Etendeka Flood Basalt are lithostratigraphically similar to those in the Kudu Gas Province, offshore Namibia, where gas-bearing aeolian sands are interspersed with lava flows. Research by the authors is focussed on the diagenetic effects, both direct and indirect, of the emplacement of the lava, and the associated sills and dykes, on the aeolian sands. Specific interests include: the compartmentalisation of the basin by sills/dykes/lava: how does this affect fluid flow paths? Diagenesis along hot contacts: is the dramatic reduction in porosity/permeability along such contacts the result of the igneous bodies alone or do they need ground water present? Can large igneous events trigger the movement of hot fluids through the basin and to what extent does this cause alteration to sediments? To address these issues we have identified a number of outcrop case studies within the Huab Basin in NW Namibia. Here, excellent 3 dimensional outcrop coupled with almost 100 percent exposure allows detailed sampling strategies to be employed on locations of interest. In some cases igneous dykes have acted as flow barriers to pore fluids and have therefore altered the type and degree of cementation either side of the dyke. Geochemical analysis of the cement can

  9. New Constraints on the Timing and Magnitude of Deformation and Basin Exhumation in the Eastern Cordillera of NW Argentina.

    Science.gov (United States)

    Trimble, J. D.; Carrapa, B.; Stockli, D. F.; Stutz, J.

    2008-12-01

    The Angastaco Basin is a ~20km wide and ~6km thick intramontane basin within the Eastern Cordillera (EC) of NW Argentina. The basin is bounded to the east and west by reverse faults that put basement rocks of the Paleozoic Puncoviscana and Cretaceous Santa Barbara Group on top of the Cenozoic sequence. Numerous faults and folds disrupt the basin internally. Some, if not most, of these structures seem to be the result of reactivation of previous normal faults related to the Salta Rift (Carrera et al. , 2006). Recent structural and thermochronological data from the EC of Argentina suggest tectonic deformation in the Eocene-Miocene (e.g., Coutand et al., 2006; Hogn et al., 2007). Data from the EC in Bolivia suggest that deformation ceased by ca. 10.7 Ma (McQuarrie et al., 2005). Therefore, different challenging questions remain open such as: (1) Are all the structures observed in the basin and along its margin a result of reactivation? (2) When was the timing and what was the magnitude of deformation within the basin and surrounding region? New detailed mapping and cross-sections in the Angastaco Basin reveal a number of faults and folds never before documented, including several km-scale west vergent folds interspersed with a complex arrangement of smaller, more angular, east-vergent faults and folds. Clear influence from both east and west-vergent deformation within the basin suggests interplay between the eastward propagation of EC related structures and westward reactivation of Santa Barbara System structures. A lack of structural continuity across the roughly E-W trending portions of Rio Calchaqui suggests that the river follows one or more unexposed strike- slip faults as it cuts across the Tertiary section from W to E. Minor offsets and lack of lateral continuity suggest that these faults are likely tear-faults coeval with deformation in the basin, although they may have been active during multiple pulses of tectonism. With an east-west trend, these structures

  10. 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.

  11. Palaeolake and palaeoenvironment between 42 and 18 kaBP in Tengger Desert, NW China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Comprehensive field investigations and laboratory analyses show that palaeolakes, including fresh- mesohaline water Megalake Tengger and other semi-con- nected, isolated water bodies, during late Pleistocene covered an area of more than 20000 km2, which is more than half of the Tengger Desert in NW China. Stratigraphic correlation and chronological evidence indicate that before ca. 42000 aBP the area was more arid. The palaeolakes started to develop around 40000 uncal. 14C aBP but until 37000 14C aBP their scope was limited. High water levels established from 35000 14C aBP lasted until 22000 14C aBP. Lake levels regressed between 22000 and 20000 14C aBP but transgressed from 20000 to 18600 14C aBP. Subsequently, water level declined further and the Megalake Tengger finally desiccated at around 18000 14C aBP. Megalake Tengger possessed a fresh-mesohaline water property, implying that the regional precipitation increased significantly. During the period of Megalake Tengger, the climate was warmer-humid than present. The annual rainfall was 250 to 350 mm more than that of today and the temperature was 1.5 to 3.0℃ higher.

  12. A review of mineral systems and associated tectonic settings of northern Xinjiang, NW China

    Directory of Open Access Journals (Sweden)

    Franco Pirajno

    2011-04-01

    Full Text Available In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogenic Belt (CAOB. The CAOB is a complex collage of ancient microcontinents, island arcs, oceanic plateaux and oceanic plates, which were amalgamated and accreted in Early Palaeozoic to Early Permian times. The establishment of the CAOB collage was followed by strike-slip movements and affected by intraplate magmatism, linked to mantle plume activity, best exemplified by the 250 Ma Siberian Traps and the 280 Ma Tarim event. In northern Xinjiang, there are numerous and economically important mineral systems. In this contribution we describe a selection of representative mineral deposits, including subduction-related porphyry and epithermal deposits, volcanogenic massive sulphides and skarn systems. Shear zone-hosted Au lodes may have first formed as intrusion-related and subsequently re-worked during strike-slip deformation. Intraplate magmatism led to the emplacement of concentrically zoned (Alaskan-style mafic–ultramafic intrusions, many of which host orthomagmatic sulphide deposits. A huge belt of pegmatites in the Altay orogen, locally hosts world-class rare metal deposits. Roll-front, sandstone-hosted U mineralisation completes the rich mineral endowment of the northern Xinjiang terranes.

  13. GRAVITY-FLOW DEPOSITS IN THE TOARCIAN PERBLA FORMATION (SLOVENIAN BASIN, NW SLOVENIA

    Directory of Open Access Journals (Sweden)

    BOSTJAN ROZIC

    2011-07-01

    Full Text Available The Perbla Formation represents typical Toarcian clay-rich pelagic sediment of the southern Tethyan passive continental margin. It was deposited in the Slovenian Basin, located in present-day western Slovenia. During the Early Jurassic the basin was surrounded by the Dinaric (Friuli Carbonate Platform to the south and by the Julian Carbonate Platform to the north. Today, the transitional areas between the platforms and basin are not preserved due to intense Cainozoic thrusting and erosion, with the only record of the evolution of these areas stored in gravity-flow deposits of the Perbla Formation. Coarser turbidites were deposited on the margins of the basin, with other types of gravity-flow deposits, observed mainly in the central part of the basin. These intercalations reflect regionally recognized events that characterized the sedimentary evolution of western Slovenia at the end of the Early Jurassic. Slumps that occasionally developed into debris-flows reflect uneven sea-bottom palaeotopography that originated during a pre- to early-Toarcian phase of accelerated subsidence. The early Toarcian transgression caused drowning of the adjacent carbonate platforms, an event reflected in the composition of coarser turbidites which consist almost exclusively of echinoderm fragments and thin-shelled bivalves. These turbidites originated from drowned platform margins and/or slopes and were subsequently redeposited in proximal parts of the basin

  14. The deformation and tectonic evolution of the Huahui Basin, northeast China, during the Cretaceous-Early Cenozoic

    Science.gov (United States)

    Huang, Shiqi; Dong, Shuwen; Zhang, Yueqiao; Zhang, Fuqin; Huang, Dezhi; Wei, Shi; Li, Zhenhong; Miao, Laicheng; Zhu, Mingshuai

    2015-12-01

    The Cretaceous Huahui basin lies along the Dunhua-Mishan fault (Dun-Mi fault), which is one of the northern branches of Tan-Lu fault in northeastern China. The study of the formation and the tectonic movements that took place in the basin can provide very important information for deciphering the tectonic evolution of northeastern China during Cretaceous-Early Cenozoic. The field analysis of fault-slip data collected from different units in the basin, demonstrates changes in the paleo-stress state that reveals a three-stage tectonic movement during the Cretaceous-Early Cenozoic. The earliest tectonic movement was NW-SE extension, which was responsible for the formation of the basin and sedimentary infilling during the Early Cretaceous. Dating of the andesite in the fill indicates it began during about 119.17 ± 0.80 Ma. The extensional structures formed in the Latest Early Cretaceous imply that this tectonic movement lasted until the beginning of the Late Cretaceous. The second stage began during the Late Cretaceous when the tectonic stress state changed and was dominated by NW-SE compression and NE-SW extension, which caused the inversion of the extensional basin. This compression folded the Early Cretaceous deposits and reactivated pre-existing faults and uplifted pre-existing granite in the basin. The strata and the unconformity in the basin shows that this compressive phase probably took place during the Late Cretaceous and ended in the Early Paleogene by a compressional regime with NE-SW compression and NW-SE extension that constitutes the third stage. The tectonic stress fields documented in the Huahui basin provide insight into the influences of plate tectonics on the crustal evolution of northeastern China during the Cretaceous to Early Cenozoic. These results show that the development of Huahui basin was controlled by the northwestward subduction of the paleo-Pacific plate during the Cretaceous, and later by the far-field effects of India-Asia collision in

  15. Late Neogene exhumation of the Piceance basin, N.W. Colorado, USA: Integrated analysis of multiple thermochronometers and subsidence modeling

    Science.gov (United States)

    Vernon, A. J.; Kendall, J. J.; Becker, T. P.; Patterson, P. E.; Reiners, P. W.; Kapp, J.

    2010-12-01

    The retrograde history of sedimentary basins is often poorly constrained by the study of subsidence, compaction, and thermal diffusion models. As part of industry/academic collaborative research on the fundamental processes active in convergent tectonics we combined multiple paleothermometers, paleobarometers, and thermochronometers on deep borehole samples with modern heat flow measurements to provide powerful constraint for estimating the exhumation history in an area. The Piceance basin (N.W. Colorado) lies east of the leading edge of the Cretaceous to early Eocene Sevier thrust belt, and is flanked by several basement-involved structures (Douglas Creek arch, White River dome, Uinta uplift, White River uplift) that exhibit growth from the Maastrichtian through the late Eocene. The youngest preserved strata within the Piceance basin are within the early Oligocene Uinta Formation, although there are deposits as young as Miocene locally preserved in the region that may have also capped the basin. The timing of uplift, river incision, and plateau-scale exhumation within this region fits into the larger context of the evolution of the Colorado River drainage system. A series of core, cutting, and surface samples were compiled to develop a synthetic well (or vertical section) of over 5000 m. Samples were collected from stratigraphic intervals ranging from the Jurassic to the Eocene and analyzed for apatite and zircon U-Th/He ages, as well as apatite fission track length distributions and ages. As the exhumation model was the unconstrained parameter, the timing and magnitude of the cooling associated with such an event was systematically varied. Thermal histories of each sampled interval were extracted from differing exhumation scenarios in the Piceance basin model (which tracks the temperature and pressure evolution during burial and denudation) and forward modeled using HeFTy. The combined use of several thermochronometers (apatite and zircon U-Th/He, apatite fission

  16. Structural deformation pattern within the NW Qaidam Basin in the Cenozoic era and its tectonic implications

    Science.gov (United States)

    Mao, Liguang; Xiao, Ancheng; Zhang, Hongwei; Wu, Zhankui; Wang, Liqun; Shen, Ya; Wu, Lei

    2016-09-01

    The Qaidam Basin is located in the northeastern Tibetan Plateau and provides an excellent field laboratory in understanding the history and mechanism of the plateau growth. It deformed widely over the northwest during the Cenozoic but with little thrust loading along the margins, where no foreland depression is observed. Based on satellite images, seismic and borehole data, we investigated the structural deformation pattern (including the structural style and timing of deformation) and its formation mechanism within the northwestern Qaidam Basin during the Cenozoic era. Mapping of surface geology shows that the modern Qaidam Basin is characterized by five SE-trending anticlinal belts. Each belt consists of several right-step en echelon anticlines with plenty of normal and strike-slip faults crossing the crests. Those anticlines are generally dominated by double fault systems at different depths: an upper thrust fault system, controlling the anticlines identified on the surface and a lower dextral transpressional fault system characterized by typical flower structures. They are separated by weak layers in the upper Xiaganchaigou or the Shangganchaigou formations. The upper system yields shortening strain 2-5 times larger than that of the lower system and the additional strain is interpreted to be accommodated by hinge-parallel elongation in the upper system. Growth strata indicate that deformation within the Qaidam Basin initiated in the middle Miocene ( 15 Ma) and accelerated in the late Miocene ( 8 Ma). A simple Riedel-P-Shear model is used to explain the deformation mechanism within the northwestern Qaidam Basin.

  17. 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

  18. Tectonic analysis of Lechada and Curavacas synclines, Yuso basin, León, NW Spain

    NARCIS (Netherlands)

    Savage, J.F.

    1967-01-01

    The structures along the southern boundary of the flysch-filled Yuso Basin bear witness to continuous epeirogenic activity during the Upper Carboniferous. The Carda\\u0148o Line foems the boundary proper but other structures, somewhat similar to this fundamental feature e.g. the Pe\\u0148a Prieta line

  19. 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

  20. Aoyitake plagiogranite in western Tarim Block, NW China:Age, geochemistry, petrogenesis and its tectonic implications

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Chuanlin; YU; Haifeng; YE; Haimin; ZHAO; Yu

    2006-01-01

    SHRIMPP U-Pb zircon age and geochemical and Nd isotopic data are reported for the Aoyitake plagiogranite in western Tarim Block, NW China. The plagiogranite intruded the Middle Proterozoic and Lower Carboniferous with an exposure area of ca. 60 km2 and crystallized at 330.7±4.8Ma. Rock types mainly include tonalite, trondhjemite and minor amounts of diorite and quartz-diorite.Feldspars in the rocks are dominated by oligoclase-andesine, and minor perthite observed locally.The granites are sodic with Na/K ratios (molar) between 4 and 87. Total REE (50-220 ppm) show a clear positive correlation with SiO2. There is no LRRE/HREE fractionation (LaN/YbN=0.5-1.5), medium negative Eu anomalies (δEu=0.3-0.6), high Y content and low Sr/Y ratio (~1.0). These granites exhibit relatively juvenile Nd T2DM model ages of 470 to 580 Ma and positive εNd(331 Ma) values of 6.23 to 7.65. The aforementioned characteristics are similar to those of ocean island or ocean ridge plagiogranites. However, the regional geology, especially its scale, precludes that the plagiogranite pluton was derived directly from fractionational crystallization of mantle-derived basaltic magma. We interpreted that the primary magma of the pluton might be tonalitic in composition generated by ca.50% partial melting of the juvenile basaltic crust. The primary magma experienced intensive fractionational crystallization, and intruded into the middle to upper crusts to form the granite pluton. In combination with the previous regional geological data, it is concluded that the plagiogranite pluton was emplaced within the Tarim Block in respond to the Carboniferous continental rifting along the Tianshan orogenic belt.

  1. Trace Element Geochemistry of Matrix Glass from the Bedout Impact Structure,Canning Basin NW Australia

    Science.gov (United States)

    Poreda, R. J.; Basu, A. R.; Chakrabarti, R.; Becker, L.

    2004-12-01

    We report on geochemical and petrographic analysis of separated matrix glass from Lagrange-1 and Bedout-1 drill cores that penetrated the Bedout structure offshore NW Australia. The results support the conclusion that the Bedout structure was produced by a a major ET impact at the end-Permian that generated shock melted glass and impact breccias (Becker et al., Science, v.304, p.1469, 2004) The Bedout structure is a 30 km, circular, 1.5 km uplifted basment high that occurs on the passive margin offshore NW Australia. The isolated feature, covered by 3 km of Triassic to Recent sediments,is not consistent with any typical volcanic province (i.e. arc or hotspot volcanism). This hypothesis is supported by the unique mineralogy and chemistry of the matrix glass. At Lagrange, major elements crudely resemble low-K, Fe-Ti basalts while the trace element patterns have two distinct signatures. The lower 250 m of Lagrange (3260 - 3010 m depth) have essentially flat REE and "spider" patterns that superficially resemble some E-MORB; a signal not typically found in arc, hotspot or continental margin settings. The upper 150 meters (3000 - 2850m) of Lagrange and the entire Bedout core (3030 - 3070m) have similar light REE-enriched patterns but low levels of alkalis, alkaline-earths and high field strength elements. Again, the chemistry is not consistent with an arc or hotspot setting, based on the low Ba and extremely low Sr (30-110 ppm) concentrations. Based on the geophysical, chemical and petrologic evidence, we hypothesize that the Bedout structure formed as the result` of an ET impact with Permian age rift margin basalts and continental sediment. The basalts did not completely melt as evidenced by the abundance of large (1 mm) An50 plagioclase,that exist as both crystalline plag and shock melted maskelynite. Plagioclase is the major repository of Sr in basalts and the lack of a plagioclase contribution to the melt glass is reflected in the low Sr abundance. Shock

  2. A new structural interpretation relating NW Libya to the Hun Graben, western Sirt Basin based on a new paleostress inversion

    Indian Academy of Sciences (India)

    K M Abdunaser; K J W McCaffrey

    2015-12-01

    The present study is based on fault-slip data (striated fault planes with known sense of slip) measured in outcrops in two structural domains located along the Hun Graben, western Sirt Basin (150 fault-slip data) and the Jifarah Basin and Nafusah Uplift, northwest Libya (200 fault-slip data). Pre-existing field data collected in two previous studies were reprocessed using standard inversion methods in MyFaultTM (v. 1.03) stereonet software, produced by Pangaea Scientific Ltd. The aim of this study was to use paleostress orientations and relative paleostress magnitudes (stress ratios), determined using the reduced stress concept, to test a new understanding of the kinematic characteristics, the relationship between the two areas and the paleostress fields that controlled the evolution of the fault systems responsible for the observed deformation. Various types of faults (normal faults, sinistral normal faults, dextral normal faults and strike-slip faults) were recorded from outcrops comprised of Mesozoic and Cenozoic sedimentary sequences in which a lineation rake is present on minor structures with displacement ranging from several centimetres to several metres. Two different domains of a NNE–SSW directed extension regime ranging from N12°E to 25°E and minor ENE–WSW and WNW–ESE compression were identified in the analysis. The results are remarkably homogeneous at all sites and consistent with progressive collisional coupling of Africa and Europe, being under approximately WNW–ESE reactivated compressional stresses during the Late Eocene-age. The new kinematic and structural conceptual model that has been proposed is a test of the prevailing tectonic models describing the Cenozoic kinematic evolution of the areas. The results show the remarkable influence of basement fabrics of different ages on the subsequent structural development of NW Libya.

  3. Site effects and soil-structure resonance study in the Kobarid basin (NW Slovenia using microtremors

    Directory of Open Access Journals (Sweden)

    A. Gosar

    2010-04-01

    Full Text Available The town of Kobarid is located in one of three areas with the highest seismic hazard in Slovenia. It was hit by several 1976–1977 Friuli sequence earthquakes and recently by the 1998 and 2004 Krn Mountains earthquakes which caused damage of intensity up to VII EMS-98 scale. The town is located in a small basin filled with heterogeneous glaciofluvial Quaternary sediments in which site effects due to soft sediments are expected. The existing microzonation which is based on surface geological data only is inadequate, and no borehole or geophysical data are available in the basin that would allow a modelling approach of site effects assessment. The microtremor horizontal-to-vertical spectral ratio (HVSR method was therefore applied in order to assess the fundamental frequency of the sediments. Investigations were performed on a 100×100 m dense grid and 106 free-field measurements acquired. Clear HVSR peaks were obtained in the majority of the surveyed area. The eastern part of the basin is characterized by two well separated peaks which indicate distinct shallow and deep impedance contrasts. The iso-frequency map of sediments shows a distribution in a broad range of 1.8–22.2 Hz. The observed frequencies can be related to the total thickness of Quaternary sediments (sand, gravel in the western part of the basin only. They are deposited over bedrock built of Cretaceous flysch. In the eastern part the obtained fundamental frequencies are influenced by the presence of a shallow conglomerate layer inside sandy gravel or lacustrine chalk. The extent of these layers was not known before. Microtremor measurements were also performed inside 19 characteristic buildings of various heights (from two to four stories, and longitudinal and transverse fundamental frequencies determined from amplitude spectra. A potential of soil-structure resonance was assessed by comparing building frequencies with the free-field sediments frequencies derived from the iso

  4. Effects of landuse change on the hydrologic regime of the Mae Chaem river basin, NW Thailand

    Science.gov (United States)

    Thanapakpawin, P.; Richey, J.; Thomas, D.; Rodda, S.; Campbell, B.; Logsdon, M.

    2007-02-01

    SummaryConflicts between upland shifting cultivation, upland commercial crops, and lowland irrigated agriculture cause water resource tension in the Mae Chaem watershed in Chiang Mai, Thailand. In this paper, we assess hydrologic regimes of the Mae Chaem River with landuse change. Three plausible future forest-to-crop expansion scenarios and a scenario of crop-to-forest reversal were developed based on the landcover transition from 1989 to 2000, with emphasis on influences of elevation bands and irrigation diversion. Basin hydrologic responses were simulated using the Distributed Hydrology Soil Vegetation Model (DHSVM). Meteorological data from six weather stations inside and adjacent to the Mae Chaem watershed during the period 1993-2000 were the climate inputs. Computed stream flow was compared to observed discharge at Ban Mae Mu gauge on Mae Mu river, Ban Mae Suk gauge on Mae Suk river, and at Kaeng Ob Luang, located downstream from the district town in Mae Chaem. With current assumptions, expansion of highland crop fields led to slightly higher regulated annual and wet-season water yields compared to similar expansion in the lowland-midland zone. Actual downstream water availability was sensitive to irrigation diversion. This modeling approach can be a useful tool for water allocation for small watersheds undergoing rapid commercialization, because it alerts land managers to the potential range of water supply in wet and dry seasons, and provides information on spatial distribution of basin hydrologic components.

  5. 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.

  6. Ethnoveterinary plant remedies used by Nu people in NW Yunnan of China

    Directory of Open Access Journals (Sweden)

    Shen Shicai

    2010-08-01

    Full Text Available Abstract Background Nu people are the least populous ethnic group in Yunnan Province of China and most are distributed in Gongshan County, NW Yunnan. Animal production plays an important role in Nu livelihoods and the Nu people have abundant traditional knowledge of animal management and ethnoveterinary practices. This study documents the animal diseases, ethnoveterinary plant remedies and related traditional knowledge in three Nu villages of Gongshan County. Methods This study was carried out in three Nu villages of Gongshan County between July 2009 and February 2010. Data was obtained through the use of semi-structured questionnaires, field observation and PRA tools. A total of 60 Nu respondents (34 men and 26 women provided information on animal ailments and ethnoveterinary plant medicines used for Nu livestock production. Information on traditional ethnoveterinary medicine knowledge and choice of treatment providers was also obtained. Results Thirty-five animal conditions were identified in the surveyed area. The major and most common animal diseases among livestock were skin conditions, diarrhea, heat, fevers, colds, and parasites. Most ailments occurred between June and August. The ethnoveterinary medicinal use of 45 plant species was documented. Most medicinal species (86.7% were collected from the wild. The most frequently used plant parts were whole plants (35.6%, followed by roots (22.2%. The most important medicinal plant species were Saussurea costus (Falc. Lipech. (UV = 0.67, Senecio scandens Buch.-Ham.ex D.Don (UV = 0.67, Plantago depressa Willd. (UV = 0.63, Rubus corchorifolius L. f. (UV = 0.62, Bupleurum yunnanense Franch. (UV = 0.60, and Polygonum paleaceum Wall. (UV = 0.60. Animal diseases treated with the highest number of ethnoveterinary plant remedies were diarrhea (16 plant species, heat, fever, colds (11 plant species, retained afterbirth (11 plant species, and skin conditions and sores (11 plant species. Many Nu villagers

  7. Paleoproterozoic subduction-related magmatism and crustal evolution of the Dunhuang Block, NW China

    Science.gov (United States)

    Wang, Zhong-Mei; Han, Chun-Ming; Xiao, Wen-Jiao; Su, Ben-Xun; Ding, Jia-Xin

    2017-02-01

    The Precambrian basement rocks of the Tarim Craton, NW China, occur mostly along the margins of the craton. These rocks have been metamorphosed under amphibolite-facies or granulite-facies, particularly in the Dunhuang and Kuluketage Blocks, whose crustal evolution and paleographic relationship are still unclear. This study presents in-situ zircon U-Pb ages and Lu-Hf isotopes and whole-rock elemental compositions for the Paleoproterozoic meta-felsic and mafic rocks in the NE Altyn Tagh area in order to constrain the Paleoproterozoic tectono-thermal events of the Dunhuang Block and to further investigate its relation to the Kuluketage Block. The meta-felsic rocks have a crystallization age of ∼1.96 Ga. Their zircon εHf(t) values vary from -0.5 to +7.2, with TDM1 model ages from 2.4 to 2.1 Ga, suggesting that their parental magmas were mainly derived from juvenile sources, with a relatively small contribution from pre-existing ancient materials. The meta-felsic rocks have geochemical affinities with typical high-Al TTG generated by slab melting except for the extremely low Cr/Ni ratios. The steeply negative slope of their REE patterns indicates that garnet and/or hornblende extraction was involved in the magma generation process. The ∼2.06 meta-mafic rocks have slightly variable positive εHf(t) values (0 to +3.4), corresponding to fairly uniform TDM1 model ages of 2.4-2.3 Ga. These results indicate that their parental magma was sourced mainly from juvenile components with minor old materials. The meta-mafic rocks have nearly flat REE patterns that bear a remarkably close resemblance to E-MORB, but the depletion in Nb, Ta, Zr, Hf and Th is typical of arc rocks. The wide range of zircon εHf(t) values from the meta-felsic and mafic rocks indicates that the Dunhuang Block experienced both crustal growth and crustal reworking during the Paleoproterozoic. In both the Dunhuang and Kuluketage Blocks, plenty of early Precambrian basement rocks experienced comparable

  8. Thorium Anomalies in the NW Quadrant of the South Pole-Aitken Basin

    Science.gov (United States)

    Haskin, Larry A.; McKinnon, William B.; Benner, Lance A. M.; Jolliff, Bradley L.

    2004-01-01

    The relatively high concentrations of Th near the Imbrium antipode in the South Pole-Aitken (SPA) basin might represent Imbrium ejecta, a consequence of convergence of Th-rich material ejected by the Imbrium impact that occurred in the Th-rich Procellarum KREEP Terrane. Here, we present landing positions for 7500 fragments ejected from Imbrium obtained by three-body (Earth-Moon-fragment) numerical integration for uniformly selected azimuthal launch positions, ejection angles of 45 deg, and velocities from 0.95 to 0.99 lunar escape. This provides an estimate of the density of infalling ejecta fragments to be expected in the vicinity of the Imbrium antipode. Similar calculations for 35 and 50 deg leave large empty regions surrounding the antipode.

  9. Active tectonics in the NW-German Basin: Evidence from correlations between the modern landscape and deep geological structures (Lower Saxony, river Hunte)

    Science.gov (United States)

    Szeder, T.; Sirocko, F.

    2003-04-01

    The catchment basin of the river Hunte (NW-German Basin, Lower Saxony) was studied on a mesoscale (length of ˜90 km) to investigate if tectonic movements in the upper crust influence modern landscape formation. Crustal movements led to upwarping of the Lower Weichselian Terrace above the transition zone of a major crustal boundery of the NW-German Basin (Lower Saxony Basin/Pompeckj Block) with an average vertical velocity of about 0,5 mm/a over the last 12 ka. The Lower Weichselian Terrace and the Hunte catchment basin are narrowest at the same position. Even the Holocene Alluvial Plain is affected by active tectonics. The Holocene Alluvial Plain is narrower and shows a negative gradient directly above a deep seated Permian salt pillow which can be traced over a vertical distance of about 4000 m as an anticline structure to the uppermost Tertiary (100 m b.s.l.). The spatial similarity of fluvial anomalies with anomalies of the geological subground indicates that crustal movements still exercise control on fluvial dynamics and are coupled to the geological predesign. Basin subsidence is thought to have triggered primarily the aggradation of the Lower Weichselian Terrace, because there is an accordance between the mean recent velocity of basin subsidence (˜-0,21 mm/a), calculated from repeated geodetic fine levelling and the mean sedimentation rate of the Lower Weichselian Terrace (˜0,2--0,4 mm/a). In addition, sedimentation rates of the Lower Weichselian Terrace were nearly constant over a time span of about 35 ka (˜47--12 ka BP). During these times the climate has changed rapidly over Northern Europe (Dansgaard-Oeschger Cycles) which affected river morphology, hydrology and sediment supply. However, the observation that no change of the mean sedimentation rate is observable indicates a long term subsiding tendency which enables accumulation of longer fluvial sequences independent of short scale climatic fluctuations. Most likely northward tilting of the NW

  10. Organic geochemistry and petroleum geology, tectonics and basin analysis of southern Tarim and northern Qaidam basins, northwest China

    Science.gov (United States)

    Hanson, Andrew Dean

    Organic geochemistry of oils from the Tarim basin, NW China, distinguish at least seven genetic groups of oils. The largest group are derived from Middle-Upper Ordovician anoxic slope-facies marls coincident with the margins of structural uplifts. Other groups include non-marine derived oils in the Luntai uplift, from southwest Tarim, in the Kuqa depression, and west of the Bachu uplift. A seep sample from west of Kashi clusters with Luntai oils. These results suggest that numerous source-rock horizons occur, but they are really restricted. Organic geochemistry of oils from northern Qaidam defines a family of hypersaline, anoxic lacustrine derived oils. Cenozoic outcrop samples from northern Qaidam are too organic lean to be of source quality, but dark laminated upper Oligocene mudstones from the Shi 28 well are of fair to good quality. Biomarkers provide a good correlation between the oils and the core samples. Organic matter is from algae and bacteria and lacks terrestrial material. Hydrocarbons are contained in upper Oligocene, Miocene, and Pliocene reservoirs. Eight oils are from NW Qaidam, but one sample comes from NE Qaidam, an area previously believed to only produce oils derived from Jurassic source rocks. Thus an unidentified Cenozoic source rock occurs in NE Qaidam. Thermal modeling indicates generation occurred in northwestern Qaidam within the last 3 million years, agreeing with observed low maturity biomarker parameters. Cenozoic stratigraphy in northern Qaidam and southern Tarim basins record the tectonic history of the surrounding structural/topographic elements. Paleocurrents record flow away from adjacent ranges from the Miocene to the present. Provenance data tie sediments to adjacent structural elements. Petrography indicates increasingly immature sandstones in Miocene and younger sediments relative to pre-Miocene samples. Apatite fission-track results from southeastern Tarim yield a cooling age of 17 +/- 1 Ma indicative of unroofing since at

  11. Integrating facies and structural analyses with subsidence history in a Jurassic-Cretaceous intraplatform basin: Outcome for paleogeography of the Panormide Southern Tethyan margin (NW Sicily, Italy)

    Science.gov (United States)

    Basilone, Luca; Sulli, Attilio; Gasparo Morticelli, Maurizio

    2016-06-01

    We illustrate the tectono-sedimentary evolution of a Jurassic-Cretaceous intraplatform basin in a fold and thrust belt present setting (Cala Rossa basin). Detailed stratigraphy and facies analysis of Upper Triassic-Eocene successions outcropping in the Palermo Mts (NW Sicily), integrated with structural analysis, restoration and basin analysis, led to recognize and describe into the intraplatform basin the proximal and distal depositional areas respect to the bordered carbonate platform sectors. Carbonate platform was characterized by a rimmed reef growing with progradational trends towards the basin, as suggested by the several reworked shallow-water materials interlayered into the deep-water succession. More, the occurrence of thick resedimented breccia levels into the deep-water succession suggests the time and the characters of synsedimentary tectonics occurred during the Late Jurassic. The study sections, involved in the building processes of the Sicilian fold and thrust belt, were restored in order to obtain the original width of the Cala Rossa basin, useful to reconstruct the original geometries and opening mechanisms of the basin. Basin analysis allowed reconstructing the subsidence history of three sectors with different paleobathymetry, evidencing the role exerted by tectonics in the evolution of the narrow Cala Rossa basin. In our interpretation, a transtensional dextral Lower Jurassic fault system, WNW-ESE (present-day) oriented, has activated a wedge shaped pull-apart basin. In the frame of the geodynamic evolution of the Southern Tethyan rifted continental margin, the Cala Rossa basin could have been affected by Jurassic transtensional faults related to the lateral westward motion of Africa relative to Europe.

  12. A microbial "bloom" at the onset of the Messinian Salinity Crisis in the Piedmont Basin (NW Italy)

    Science.gov (United States)

    Natalicchio, Marcello; Birgel, Daniel; Dela Pierre, Francesco; Lozar, Francesca; Liu, Xiaolei; Hinrichs, Kai-Uwe; Peckmann, Jörn

    2015-04-01

    The Messinian Salinity Crisis (MSC), a severe ecological crisis that occurred in the Mediterranean Basin about 6 myr ago, had drastic consequences for both freshwater and marine ecosystems (Roveri et al., 2014). The response of prokaryotes to the changing conditions at the MSC onset is virtually unknown. In a lipid biomarker study of sediments straddling the MSC onset from the Pollenzo section (NW Italy), we aim to evaluate the response of microbial communities at the transition from normal marine to extreme conditions. In this section, the advent of the MSC does not coincide with the deposition of gypsum; instead shales and intercalated carbonate-rich beds deposited. These deposits are considered as the deep water counterparts of gypsum layers that formed in the shallower parts of the basin (Dela Pierre et al., 2012). In both pre-MSC and MSC deposits, the molecular fossil inventory is sourced from all three domains of life and is mainly represented by isoprenoidal alcohols, fatty acids, sterols, long chain n-alkanes and n-alcohols. However, after the MSC onset, a sharp increase of the long chains n-alkanes, n-alcohols and fatty acids occurs, indicating a significant increase of terrigenous organic matter, most likely sourced by enhanced riverine runoff. Remarkably, this coincides with an increase of sterols (sitosterol and dinosterol), that are typically interpreted as markers of phytoplankton. The same strata contain filamentous fossils, which have been interpreted as remains of sulfide-oxidizing bacteria (cf., Dela Pierre et al., 2012). The basal MSC deposits are also typified by an increase of isoprenoidal alcohols, including glycerol dibiphytanyl glycerol tetraethers (GDGTs) and diphytanyl glycerol diethers (DGD). Caldarchaeol and crenarchaeol are the overall most abundant GDGTs. Their almost equal distribution in pre-MSC deposits suggests that they derived from planktic Thaumarchaeota, which are abundant picoplanktonic organisms in modern oceans. In contrast

  13. 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.

  14. 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.

  15. Tarim Basin: China's Potential Oil Giant

    Institute of Scientific and Technical Information of China (English)

    Qiu Baolin

    1996-01-01

    @@ Tarim Basin has an area of 560,000 square kilometers.Taklamakan Desert, the world's second largest shifting desert, is located in the hinterland of the basin. The desert is equal to Germany in area. The desert is called "Desert of No Return" for its harsh and adverse environments. A 522-kilometer highway crossing the desert from north to south was opened to the traffic in 1995 because an oilfield with the reserves of more than 100 million tons was discovered in the central part of the basin. The local traffic and ecological conditions have been much improved in the recent years.

  16. Spatial Preference Heterogeneity for Integrated River Basin Management: The Case of the Shiyang River Basin, China

    Directory of Open Access Journals (Sweden)

    Fanus Asefaw Aregay

    2016-09-01

    Full Text Available Integrated river basin management (IRBM programs have been launched in most parts of China to ease escalating environmental degradation. Meanwhile, little is known about the benefits from and the support for these programs. This paper presents a case study of the preference heterogeneity for IRBM in the Shiyang River Basin, China, as measured by the Willingness to Pay (WTP, for a set of major restoration attributes. A discrete choice analysis of relevant restoration attributes was conducted. The results based on a sample of 1012 households in the whole basin show that, on average, there is significant support for integrated ecological restoration as indicated by significant WTP for all ecological attributes. However, residential location induced preference heterogeneities are prevalent. Generally, compared to upper-basin residents, middle sub-basin residents have lower mean WTP while lower sub-basin residents express higher mean WTP. The disparity in utility is partially explained by the difference in ecological and socio-economic status of the residents. In conclusion, estimating welfare benefit of IRBM projects based on sample responses from a specific sub-section of the basin only may either understate or overstate the welfare estimate.

  17. Mapping Electrical Structures in the Jarud Basin, Northeast China through Magnetotelluric Sounding

    Science.gov (United States)

    Zhao, W.

    2015-12-01

    In recent years, China Geological Survey (CGS) has launched 3D geological mapping programs from regional to local scales. The project Deep geological survey at the periphery of the Songliao Basin funded by CGS was implemented from 2012 to 2014. Its main goals are to reveal the tectonic framework of the Jarud Basin (JB) as well as to identify the strata distribution of Permian Linxi Formation by integrating new electromagnetic data with existing geophysical and geological data since black mudstones in the Linxi Formation have shown the potential of shale gas. The study area covered dominantly with Cretaceous-Jurassic igneous rocks with exception of the southeast part is situated in Jarud Banner and Ar Horqin Banner, Inner Mongolia, China. It tectonically lies in the southern Great Khingan Range, western margin of the Songliao Basin, and north of Xar Moron Fault. Over the period of 2012 to 2014, a magnetotelluric survey was carried out at the JB. A total of 926 MT sites with nominal spacing 1 km was acquired in the effective frequency range of 0.01 Hz ~ 300 Hz on six NW and five NE profiles, covering area that exceeds 10, 000 km2. After dimensionality analysis and static shift removal, the nonlinear conjugate algorithm was used to conduct 2D inversion for TM and TE modes. The resistivity models underwent examination using sensitivity tests. The optimal resistivity models revealed numerous large faults, some of which constitute the boundaries of the JB, and modified the tectonic framework. Integrated with well logging and geological mapping data, the strata of Linxi Formation were identified and classified into three depressions: Depressions Arituguri, Gadasu and Wufen. Attention should be paid to Depression Gadasu with area of around 500 km2 since it contains reasonably thick conductive sediments exceeding 4 km in depth which are inferred to be black mudstones pertaining to shale gas.

  18. Geochemistry of Metamafic Dykes from the Quanji Massif:Petrogenesis and Further Evidence for Oceanic Subduction, Late Paleoproterozoic, NW China

    Institute of Scientific and Technical Information of China (English)

    Hassan Abdelslam Mustafa; Qinyan Wang; Nengsong Chen; Fanxi Liao; Min Sun; Meshaal Abdelgadir Salih

    2016-01-01

    A suite of ~1.84–1.92 Ga metamafic dykes within the paragneiss suite (khondalite) of the Quanji massif in NW China, has been chosen in this study for further understanding the tectonic evo-lution and possible links to the global Columbia supercontinent. Occurrence and field relations sug-gest that they were formed coevally with a previous studied ~1.83–1.85 Ga metamafic dyke swarms. Whole-rock major and trace elemental geochemistry suggests precursor magma of the amphibolites being generated from a volcanic arc-related tectonic setting rather than a back-arc environment where the metamafic dyke swarms were emplaced. The metamafic dykes show enrichment of LREE and strongly negative anomalies for Ta-Nb, Zr-Hf and Ti, have high SiO2 (49.3 wt.%–52.5 wt.%) but low MgO (6.40 wt.%–7.76 wt.%) contents and Mg# (Mg#=[100×(MgO/40.3)]/[MgO/40.3+FeO/71.8]) values (45.7–52.1), suggesting evolved precursor magma. The high values of La/Ta (22.2–42.8) and La/Nb (1.71–2.47), mildly negativeεNd(t) values (-2.51–0.15), with depleted mantle model ages (TDM) of 2.45–2.84 Ga, suggest that their precursor magmas were possibly derived from a subduction-related fluid metasomatized Archean sub-continental lithospheric mantle. This study provides further evi-dence for oceanic plate subduction prevailing before or around ~1.85 Ga, which confirms a prolonged subduction-accretion-collision history in the NW China which is possibly linked to the assembly of the Columbia supercontinent.

  19. Geochemistry and petrology of the Early Miocene lamproites and related volcanic rocks in the Thrace Basin, NW Anatolia

    Science.gov (United States)

    Ersoy, Yalçın E.; Palmer, Martin R.; Uysal, İbrahim; Gündoğan, İbrahim

    2014-08-01

    The extensional Thrace basin (NW Anatolia) contains an association of early Miocene diopside-leucite-phlogopite (Doğanca) and diopside-phlogopite (Korucuköy) lamproites with Oligocene medium-K calc-alkaline andesites (Keşan volcanics), early Miocene shoshonitic rocks (Altınyazı trachyte) and middle Miocene Na-alkaline basalts (Beğendik basalts). The Doğanca lamproite (K2O = 5.1-5.5 wt.%; K/Na = 2.78-2.89; MgO = 11.4-11.8 wt.%) consists of olivine (Fo71-86), diopside (Al2O3 = 1.0-5.0, Na2O = 0.2-0.6), phlogopite (TiO2 = 1.1-9.4, Al2O3 = 11.1-13.9), spinel (Mg# = 22.9-32.6; Cr# = 64-83.4), leucite, apatite, zircon, Fe-Ti-oxides and magnetite in a poikilitic sanidine matrix. The potassic volcanic units (lamproites and trachytes) in the region have similarly high Sr and low Nd isotopic compositions (87Sr/86Sr(i) = 0.70835-0.70873 and 143Nd/144Nd(i) = 0.51227-0.51232). The major and trace element compositions and Sr-Nd-Pb isotopic ratios of the shoshonitic, ultrapotassic and lamproitic units closely resemble those of other Mediterranean ultrapotassic lamproites (i.e., orogenic lamproites) from Italia, Serbia, Macedonia and western Anatolia. The Beğendik basalts show intraplate geochemical signatures with an Na-alkaline composition, an absence of Nb negative anomalies on primitive mantle-normalized multi-element diagrams, as well as low Sr (~ 0.70416) and high Nd (0.51293) isotopic ratios; and include olivine (Fo72-84), diopside, spinel, Fe-Ti-oxides and magnetite. The Oligocene Keşan volcanics were emplaced in the earlier stages of extension in Thrace, and represent the typical volcanic products of post-collisional volcanism. The continental crust-like trace element abundances and isotopic compositions of the most primitive early Miocene ultrapotassic rocks (Mg# up to 74) indicate that their mantle sources were intensely contaminated by the continental material. By considering the geodynamic evolution of the region, including oceanic subduction, crustal

  20. Sequence stratigraphy and depositional environments of the Sarmatian sediments in the NW part of the Vienna Basin: Moravian Central Depression, Czech Republic

    Directory of Open Access Journals (Sweden)

    Bohuslava Sopková

    2009-01-01

    Full Text Available The study is focused on the development of the Sarmatian sedimentary record in the NW Vienna Basin, Moravian Central Depression. To identify key surfaces, the principles of sequence stratigraphy and electrosequence analysis were used together with the well logs and well cores data as well as data obtained from final reports. The identified sequence boundaries (SB and surfaces (ts, mfs divide the Sarmatian sediments into sequences of the relative base level change of the third and fourth order. Except the third order cycle related to Haq's TB 2.6 cycle, which includes the whole Sarmatian stage, two individual cycles of higher order were revealed in the sedimentary record for the Moravian Central Depression. Their occurrence was also proved in Austrian as well as in Slovak part of the Vienna Basin, what points to their interregional character.

  1. Upper Paleozoic petroleum system, Ordos Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, X.M.; Zhao, B.Q.; Thu, Z.L.; Song, Z.G. [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wilkins, R.W.T. [CSIRO Petroleum, P.O. Box 136, North Ryde, NSW 2113 (Australia)

    2005-09-01

    The Ordos Basin is a typical lapped basin, including three sequences of strata: early Paleozoic, late Paleozoic and Mesozoic, with a total thickness of 4000-6000m. Impermeable sealing beds are well developed at the top and base of the upper Paleozoic sequence, separating it from the Mesozoic and the lower Paleozoic strata to form an independent petroleum system. In this petroleum system, the source rocks are widely distributed coals and dark mudstones occurring in the Carboniferous-lower Permian coal measures, with a thickness of 10-15 and 40-60m, respectively. The reservoirs are mainly early Permian tight sandstones, mostly with a porosity of 4-8% and a permeability of 0.1-1.0x10{sup -3}{mu}m{sup 2}. The regional cap rock is a 100-150m thick mudstone in the upper Permian strata. The structural framework of the basin is a huge asymmetric syncline, dipping gently toward the east and north, and steeply toward the south and west. Well data show that gas-saturated, gas-water transition and water-saturated zones are developed from the depositional center to the basin edges. The gas-saturated zone mainly lies in the gently dipping slope area of the Shanbei Slope. Toward eastern and northern up-dip directions the water-gas transitional zone occurs, and finally the water-saturated zone, presenting a reverse relation of water on top of gas. An abnormal negative strata pressure is developed in the gas-bearing area, with a pressure coefficient (C{sub p}) ranging from 0.83 to 0.95. Fluid inclusion data indicate that the upper Paleozoic gas pool began to develop around the Wuqi area at about 150Ma, and it extended toward the north and was largely formed at about 120Ma, showing there was a regional migration of the gas-water interface from south to north during the gas pool formation. These characteristics appear to show that the northern and eastern margins of the petroleum system are defined by a regional hydrodynamic regime. The critical moment of the petroleum system

  2. Characterising the nature, evolution and origin of detachment fault in central depression belt, Qiongdongnan Basin of South China Sea:evidence from seismic reflection data

    Institute of Scientific and Technical Information of China (English)

    REN Jianye; YANG Linlong; ZHANG Daojun; TONG Dianjun; HUANG Anmin; WANG Yahui; LEI Chao; ZUO Qianmei; ZHAO Yanghui; HE Weijun

    2014-01-01

    Using regional geological, newly acquired 2D and 3D seismic, drilling and well log data, especially 2D long cable seismic profiles, the structure and stratigraphy in the deep-water area of Qiongdongnan Basin are interpreted. The geometry of No.2 fault system is also re-defined, which is an important fault in the central depression belt of the deep-water area in the Qiongdongnan Basin by employing the quantitative analysis techniques of fault activity and backstripping. Furthermore, the dynamical evolution of the No.2 fault sys-tem and its controls on the central depression belt are analyzed. This study indicates that the Qiongdongnan Basin was strongly influenced by the NW-trending tensile stress field during the Late Eocene. At this time, No.2 fault system initiated and was characterized by several discontinuous fault segments, which controlled a series small NE-trending fault basins. During the Oligocene, the regional extensional stress field changed from NW-SE to SN with the oceanic spreading of South China Sea, the early small faults started to grow along their strikes, eventually connected and merged as the listric shape of the No.2 fault system as ob-served today. No.2 fault detaches along the crustal Moho surface in the deep domain of the seismic profiles as a large-scale detachment fault. A large-scale rollover anticline formed in hanging wall of the detachment fault. There are a series of small fault basins in both limbs of the rollover anticline, showing that the early small basins were involved into fold deformation of the rollover anticline. Structurally, from west to east, the central depression belt is characterized by alternatively arranged graben and half-graben. The central depression belt of the Qiongdongnan Basin lies at the extension zone of the tip of the V-shaped northwest-ern ocean sub-basin of the South China Sea, its activity period is the same as the development period of the northwestern ocean sub-basin, furthermore the emplacement and

  3. 2.6 Ga Gabbro-tonalite-trondhjemite Complex and 2.5 Ga Potassic Granite in Quruqtagh. Geochronology, Geochemistry and Their Implications on the Early Precambrian Tectonic Evolution of the Tarim Block, NW China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chuan-lin; LI Xian-hua; LI Zheng-xiang; YE Hai-min

    2008-01-01

    @@ Field observation, ages and geochemistry of the Neoarchaean intrusive complex in Quruqtagh in northern mar-gin of the Tarim Block, NW China, are reported to decipher the Neoarchaean tectonic evolution of the Tarim Block.

  4. HELIUM, PARTICULATE ORGANIC CARBON and other data from HEIYO, KAIYO and other platforms in the NW Pacific, Philippine Sea and East China Sea from 1939-08-17 to 1988-09-27 (NCEI Accession 9000197)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A tape containing part of the annual exchange of chemical data from the Japan Oceanographic Data Center collected from East China Sea (Tung Hai), Philippine Sea, NW...

  5. Sedimentary basin analysis using airborne gravity data: a case study from the Bohai Bay Basin, China

    Science.gov (United States)

    Li, Wenyong; Liu, Yanxu; Zhou, Jianxin; Zhou, Xihua; Li, Bing

    2016-11-01

    In this paper, we discuss the application of an airborne gravity survey to sedimentary basin analysis. Using high-precision airborne gravity data constrained by drilling and seismic data from the Bohai Bay Basin in eastern China, we interpreted faults, structural elements, sedimentary thickness, structural styles and local structures (belts) in the central area of the Basin by the wavelet transform method. Subsequently, these data were subtracted from the Bouguer gravity to calculate the residual gravity anomalies. On this basis, the faults were interpreted mainly by linear zones of high gravity gradients and contour distortion, while the sedimentary thicknesses were computed by the Euler deconvolution. The structural styles were identified by the combination of gravity anomalies and the local structures interpreted by the first vertical derivative of the residual gravity. The results showed evidence for seven faults, one sag and ten new local structure belts.

  6. Dating the Indo-Asia collision in NW Himalaya: constraints from Sr-Nd isotopes and detrital zircon (U-Pb) and Hf isotopes of Paleogene-Neogene rocks in the Katawaz basin, NW Pakistan

    Science.gov (United States)

    Zhuang, Guangsheng; Najman, Yani; Millar, Ian; Chauvel, Catherine; Guillot, Stephane; Carter, Andrew

    2015-04-01

    The time of collision between the Indian and Asian plates is key for understanding the convergence history and the impact on climatic systems and marine geochemistry. Despite much active research, the fundamental questions still remain elusive regarding when and where the Indian plate collided with the Asian plate. Especially in the west Himalaya, the questions become more complex due to disputes on the amalgamation history of interoceanic Kohistan-Ladakh arcs (KLA) with Karakoram of the Asian plate and the Indian plate. Here, we present a result of multiple-isotopic geochemistry and geochronology study in the Katawaz Basin in NW Pakistan, a remnant oceanic basin on the western Indian plate which was the repository for the sediments eroded from the west Himalaya ( Qayyum et al., 1996, 1997a, 1997b, 2001; Carter et al., 2010), to evaluate the time and character of collision in this region. In this study, we analyzed 22 bulk mudstone samples for Sr-Nd isotopes and 11 medium-grained sandstones for detrital zircon (U-Pb) geochronology and Hf isotopes. We constructed the Cenozoic chronology in the Katawaz Basin based on our newly collected detrital zircon U-Pb ages and fission track ages. We present the first record of Katawaz chronology that constrained the Khojak Formation to be current study revealed that the Katawaz sedimentary sequence ranges in age from Eocene to the earliest Miocene. The samples from the Nisai Formation show the 87Sr/86Sr - ɛNd values overlapping those of the end member of the Karakoram of Asian origin, revealing the arrival of Asian detritus on the Indian plate prior to 50 Ma. There are two parallel lines of evidence supporting this conclusion: (1) young zircon grains (Journal of the Geological Society 154, 753-756. Qayyum, M., Lawrence, R.D., Niem, A.R., 1997b. Molasse-Delta-flysch continuum of the Himalayan orogeny and closure of the Paleogene Katawaz Remnant Ocean, Pakistan. International geology review 39, 861-875. Qayyum, M., Niem, A

  7. 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.

  8. New insights on the maturity distribution and shale gas potential of the Lower Saxony Basin, NW-Germany

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, B.; Littke, R. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Di Primio, R. [Deutsches GeoForchungsZentrum (GFZ), Potsdam (Germany). Sektion 4.3 - Organische Geochemie; Berner, U. [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany)

    2013-08-01

    Due to its economic relevance the Lower Saxony Basin has been intensively investigated. Consequently it can be regarded as a well-known example of a sedimentary basin that experienced strong inversion. Oil and gas source rocks of economical importance comprise Upper Carboniferous coals as well as Jurassic (Toarcian/Posidonia Shale) and Cretaceous (Berriasian/Wealden) marls. Many basin modeling projects have addressed this area but until now the tectonic and maturation history as well as the petroleum system evolution has not been evaluated in a high-resolution 3D model. Therefore, a fully integrated 3D high-resolution numerical petroleum system model was developed incorporating the Lower Saxony Basin and major parts of the Pompeckj Block, and Muensterland Basin. The burial and maturation history has been reconstructed calibrated by large amounts of vitrinite reflectance and downhole temperature data enabling the output of erosion and maturity distribution maps of superior quality. (orig.)

  9. 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

  10. 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.

  11. Paleogene magnetic isochrons and palaeo-propagators in the Arabian and Eastern Somali basins, NW Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.; Dyment, J.; Bhattacharya, G.C.; Royer, J.-Y.; Srinivas, K.; Yatheesh, V.

    A revised magnetic isochron map of the conjugate Arabian and Eastern Somali basins based on an up-to-date compilation of Indian, French, and other available sea-surface magnetic data are presented. The magnetic anomaly and the modulus...

  12. [Substance flow analysis on phosphorus cycle in Dianchi basin, China].

    Science.gov (United States)

    Liu, Yi; Chen, Ji-Ning

    2006-08-01

    Investigation of physical profiles of nutrients within socio-economic systems is one of the key approaches to cure eutrophication. Applying a substance flow analysis (SFA) method for the case of Dianchi basin located in southwest of China, we established a regional static SFA model (PHOSFAD) in 2000 via balancing societal phosphorus flows. Aggregate characteristics of the overall phosphorus throughput, and physical efficiencies in relation to phosphorus uses of production and consumption sectors, including mining, processing, farming, livestock husbandry and household consumption, were subsequently identified. The methodology and results of this study illustrate applicability and value for rational decision-making aiming to curb eutrophication of Dianchi Lake.

  13. 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

  14. 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.

  15. 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.

  16. Bashikaogong-Shimierbulake granitic complex,north Altun,NW China: Geochemistry and zircon SHRIMP ages

    Institute of Scientific and Technical Information of China (English)

    WU; Cailai; YAO; Sunzhi; ZENG; Lingsen; YANG; Jingsui; Joseph; L.Wooden; CHEN; Songyong; Frank; K.Mazdab

    2006-01-01

    The Bashikaogong-Shimierbulake granitoid complex is about 30 km long and 2-6 km wide,with an area of 140 km2,located at the north margin of the Bashikaogong Basin in the north Altun terrain.It intruded into schist,metapelite and metatuff of Precambrian ages.This granitoid complex consists of darkish quartz diorite,grey granite,pink granite and pegmatite.Geochemically,the quartz diorite has I-type granite affinity and belongs to Calc-alkaline sereies,and the other granites have S-type affinity and to high-K calc-alkaline series.Zircon SHRIMP U-Pb dating shows that the quartz diorite has a bigger age than those of other granites,which is 481.6±5.6 Ma for quartz diorite,437.0±3.0 Ma-433.1±3.4 Ma for grey granite and 443±11 Ma-434.6±1.6 Ma for pink granite,respectively.Combined with regional geology,we think that the quartz diorite formed in tectonic environment related to oceanic crust subduction and the granites in post-collision.

  17. 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.

  18. Paleozoic magmatism and porphyry Cu-mineralization in an evolving tectonic setting in the North Qilian Orogenic Belt, NW China

    Science.gov (United States)

    Qiu, Kun-Feng; Deng, Jun; Taylor, Ryan D.; Song, Kai-Rui; Song, Yao-Hui; Li, Quan-Zhong; Goldfarb, Richard J.

    2016-01-01

    The NWW-striking North Qilian Orogenic Belt records the Paleozoic accretion–collision processes in NW China, and hosts Paleozoic Cu–Pb–Zn mineralization that was temporally and spatially related to the closure of the Paleo Qilian-Qinling Ocean. The Wangdian Cu deposit is located in the eastern part of the North Qilian Orogenic Belt, NW China. Copper mineralization is spatially associated with an altered early Paleozoic porphyritic granodiorite, which intruded tonalites and volcaniclastic rocks. Alteration zones surrounding the mineralization progress outward from a potassic to a feldspar-destructive phyllic assemblage. Mineralization consists mainly of quartz-sulfide stockworks and disseminated sulfides, with ore minerals chalcopyrite, pyrite, molybdenite, and minor galena and sphalerite. Gangue minerals include quartz, orthoclase, biotite, sericite, and K-feldspar. Zircon LA-ICPMS U–Pb dating of the ore-bearing porphyritic granodiorite yielded a mean 206Pb/238U age of 444.6 ± 7.8 Ma, with a group of inherited zircons yielding a mean U–Pb age of 485 ± 12 Ma, consistent with the emplacement age (485.3 ± 6.2 Ma) of the barren precursor tonalite. Rhenium and osmium analyses of molybdenite grains returned model ages of 442.9 ± 6.8 Ma and 443.3 ± 6.2 Ma, indicating mineralization was coeval with the emplacement of the host porphyritic granodiorite. Rhenium concentrations in molybdenite (208.9–213.2 ppm) suggest a mantle Re source. The tonalities are medium-K calc-alkaline. They are characterized by enrichment of light rare-earth elements (LREEs) and large-ion lithophile elements (LILEs), depletion of heavy rare-earth elements (HREEs) and high-field-strength elements (HFSEs), and minor negative Eu anomalies. They have εHf(t) values in the range of +3.6 to +11.1, with two-stage Hf model ages of 0.67–1.13 Ga, suggesting that the ca. 485 Ma barren tonalites were products of arc magmatism incorporating melts from the mantle wedge and

  19. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    Science.gov (United States)

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu

    2016-07-01

    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  20. Geochronology and geochemistry of the high Mg dioritic dikes in Eastern Tianshan, NW China: Geochemical features, petrogenesis and tectonic implications

    Science.gov (United States)

    Li, Deng-Feng; Zhang, Li; Chen, Hua-Yong; Hollings, Pete; Cao, Ming-Jian; Fang, Jing; Wang, Cheng-Ming; Lu, Wan-Jian

    2016-01-01

    Zircon U-Pb ages of high Mg dioritic dikes in the Mesoproterozoic Kawabulake Group in the Eastern Tianshan area, NW China indicate that they were emplaced in the Early Carboniferous at 353-348 Ma. The dikes consist of medium-grained plagioclase and hornblende with minor clinopyroxene and trace quartz. They are characterized by intermediate SiO2 (60-62 wt.%), low TiO2 (0.63-0.71 wt.%), relatively high Al2O3 (15.1-15.8 wt.%) and MgO contents (3.45-4.15 wt.%) with Mg# generally higher than 56 (56-59). The geochemistry of the high Mg diorites suggest they were formed by similar magmatic processes to sanukitoid high Mg Andesites such as those of the Setouchi volcanic belt, Japan. Zircons from the high Mg dioritic dikes have εHf(t) values of -6.8 to +14.5. The dominantly positive values suggest a juvenile source, whereas the small number of negative values suggests mature components were also incorporated into the source. Similarly, the positive εNd(t) values (0 to +2.2) are interpreted to reflect a juvenile source whereas the negative values of (-5.2 to 0) suggest participation of old crustal rocks in the petrogenesis of the diorites. The variable εHf(t) and εNd(t) values suggest that the mature material was assimilated during magma ascent rather than in the mantle wedge which would result in more uniform values. Mass balance calculations suggest that the dioritic dikes were derived from sources composed of approximately 97% juvenile mantle-derived material and 3% sediment. Petrographic, elemental, and isotopic evidence suggest that the dioritic dikes were generated by partial melting of depleted mantle that migrated into the shallow crust where it assimilated older sedimentary rocks of the Mesoproterozoic Kawabulake Group.

  1. Active flexural-slip faulting: A study from the Pamir-Tian Shan convergent zone, NW China

    Science.gov (United States)

    Li, Tao; Chen, Jie; Thompson, Jessica A.; Burbank, Douglas W.; Yang, Xiaodong

    2015-06-01

    The flexural-slip fault (FSF), a type of secondary fault generated by bed-parallel slip, occurs commonly and plays an important role in accommodating fold growth. Although the kinematics and mechanics of FSFs are well studied, relatively few field observations or geometric models explore its geomorphic expression. In the Pamir-Tian Shan convergent zone, NW China, suites of well-preserved FSF scarps displace fluvial terraces in the Mingyaole and Wulagen folds. Integrating interpretations of Google Earth images, detailed geologic and geomorphic mapping, and differential GPS measurements of terrace surfaces, we summarize geomorphic features that typify these faults and create kinematic models of active flexural-slip faulting. Our study indicates the following: (i) FSF scarps commonly occur near synclinal hinges, irrespective of whether (a) the dip direction of beds on either side of the hinge is unidirectional or in opposite directions, (b) the hinge is migrating or fixed, or (c) the hinge shape is narrow and angular or wide and curved. (ii) Active FSFs are likely to produce higher scarps on steeper beds, whereas lower or no topographic scarps typify gentler beds. (iii) Tilt angles of the terrace surface displaced above FSFs progressively decrease farther away from the hinge, with abrupt changes in slope coinciding with FSF scarps; the changes in tilt angle and scarp height have a predictable geometric relationship. (iv) Active FSFs can accommodate a significant fraction of total slip and play a significant role in folding deformation. (v) Active FSFs may be used to assess seismic hazards associated with active folds and associated blind thrusts.

  2. Re-Os pyrite geochronology of Zn-Pb mineralization in the giant Caixiashan deposit, NW China

    Science.gov (United States)

    Li, Dengfeng; Chen, Huayong; Hollings, Pete; Zhang, Li; Mi, Mei; Li, Jie; Fang, Jing; Wang, Chengming; Lu, Wanjian

    2016-03-01

    The newly discovered Caixiashan Irish-type Zn-Pb deposit (˜131 Mt at 3.95 % Zn + Pb), located in the Eastern Tianshan of Xinjiang, is one of the largest Zn-Pb deposits in NW China. Massive colloform/framboidal textured syn-sedimentary pyrite yielded a Re-Os isochron age of 1019 ± 70 Ma (MSWD = 3.5), which is interpreted to be the depositional age of the Kawabulake group that hosts the ore. The age of the main mineralization stage is constrained by two types of pyrite: the layered pyrite coexists with recrystallized calcite and dolomite and is locally replaced by sphalerite, whereas the euhedral pyrite occurs with galena that crosscuts the massive sphalerite. The layered pyrite yielded a Re-Os age of 859 ± 79 Ma (MSWD = 6.7; initial 187Os/188Os ratio [IOs] = 0.19 ± 0.25) and the euhedral pyrite 837 ± 39 Ma (MSWD = 6.5; [IOs] = 0.16 ± 0.09), which are interpreted to be the Zn and Pb mineralization ages, respectively. The low radiogenic initial Os values of the Zn-Pb mineralization suggest interaction between a hydrothermal fluid and a mafic or ultramafic source rock with a mantle Os signature with some contamination with Mesoproterozoic Kawabulake group. Based on our new Re-Os ages, we conclude that the giant Caixiashan Zn-Pb deposit formed in the early Neoproterozoic and it represents a newly identified mineralization epoch in the Eastern Tianshan of the Central Asia Orogenic Belt.

  3. Chronology and origin of Au-Cu deposits related to Paleozoic intracontinental rifting in West Tianshan Mountains, NW China

    Institute of Scientific and Technical Information of China (English)

    李华芹; 陈富文

    2002-01-01

    Located between the Tarim platform and Junggar massif, the West Tianshan intracontinental rift abuts against the China-Kazakhstan boundary in the west part, borders on the Yilianhabierga late Paleozoic relic ocean basin and the South Tianshan late Paleozoic ocean basin respectively in the northeast separated by the Aibi Lake fault and in the southeast by the fault along the southern margin of the Yili massif. During the development and after the close of the West Tianshan intracontinental rifting in the Carboniferous-Permian period, a series of nonferrous and precious metal mineralizations occurred with the Au-Cu deposits being the most important. Isotopic chronologic study of representative deposits of different types shows that gold-copper mineralization in the West Tianshan intracontinental rift zone mainly happened during the middle-late Hercynian Period, among which the Axi volcanic hydrothermal type gold deposit was formed during the Carboniferous with a fluid inclusion Rb-Sr isochron age of (339 ± 28) Ma; the Qiabukanzhuota quartzolite type gold deposit has a Rb-Sr isochron age of (312 ± 46) Ma; the Tawuerbieke porphyry type gold deposit has a Rb-Sr isochron age of (295 ± 16) Ma; the Jingbulak magmatic liquation Cu-Ni deposit and the Musizaote porphyry type Cu deposit have the forming ages of 300 Ma ± and 250 Ma ±, respectively. Analyses of crustal evolution and metallogenetic geological backgrounds of Au-Cu mineralizations in the studied area shows a close correlation with the rifting.

  4. 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

  5. Remote sensing and field analysis of the Palaeozoic structural style in NW Libya: The Qarqaf arch a paleo-transfer fault zone between the Ghadamis and Murzuq basins

    Science.gov (United States)

    Chorowicz, Jean; Benissa, Mahmoud

    2016-11-01

    The N75°E-trending Qarqaf arch in NW Libya separates the Ghadamis and Murzuq basins. We have updated existing geological maps by remote sensing analysis and fieldwork in order to describe the tectonic style of the Palaeozoic units. We have evidenced a Bir Aishah anticline, a Wadi Ash Shabiyat graben and arrays of sedimentary and/or vein quartz dykes that relate to extension fractures or open faults some of them being filled up by on-going sedimentation. We show that continuous brittle syn-depositional deformation occurred throughout the Palaeozoic and progressively with time focused into major faults. The Qarqaf arch is a Palaeozoic right-lateral fault zone comprising main conjugate dextral N60°E and sinistral N90°E fault families. It also comprises ∼ N-striking extensional faults with related drag or fault-propagation folds. The Palaeozoic tectonic style is that of rift basins connected by a major transfer fault zone. The arch is as a consequence of strike-slip mechanism. In order to account for distinct folds affecting the Carboniferous strata we argue that partly consolidated silty Devonian and Carboniferous deposits slid in mass by places at the end of their deposition over tilting Devonian layers. Our model is alternative to the currently considered concept of major Variscan compressional orogen in this area. The regional so called 'Variscan' age disconformity actually is the Triassic early Neo-Tethyan event. These general concepts have potential impact on basin modelling of subsidence, uplift, thermal history and hydrocarbon migration. Any new structural geology study in this area is important for oil exploration.

  6. A Devonian to Carboniferous intra-oceanic subduction system in Western Junggar, NW China

    Science.gov (United States)

    Zhang, Ji'en; Xiao, Wenjiao; Han, Chunming; Mao, Qigui; Ao, Songjian; Guo, Qianqian; Ma, Chong

    2011-07-01

    The Devonian and Carboniferous rock assemblages in Western Junggar, southern Altaids, include ophiolitic mélanges and coherent units. At Baijiantan, Yeyagou and Dagun Devonian gabbros and one group of volcanic rocks (type I lava) generally crop out as blocks in a matrix of ultramafic rocks and/or mudstone. They have a depleted light rare earth element (LREE) and mid-oceanic ridge basalt (MORB)-like signature with a small negative Nb anomaly, suggesting formation in a back-arc basin. Another group of volcanic rocks (type II lava) from Baijiantan, Yeyagou, Western Karamay and Maliya includes alkaline basalt, basanite, andesite, dacite and trachyte that contain microphenocrysts of clinopyroxene-plagioclase, amygdales filled with chalcedony and calcite, and accessory pyrite and ilmenite. The type II lavas are further subdivided into five sub-types: (1) Type II1 lava is strongly enriched in LREE with incompatible trace element ratios similar to oceanic island basalt (OIB), suggesting derivation from enriched mantle. (2) Type II2 lava and tuff are slightly LREE-enriched, with a marked negative Nb anomaly and Th/Yb-enrichment indicating that they were generated in a supra-subduction zone (SSZ). (3) Type II3 lava is also moderately enriched in LREE suggesting derivation from a more-enriched MORB mantle. (4) Type II4 lava is enriched in LREE and has high Nb/Yb values close to those of OIB. It is extensively depleted in Nb suggesting a source containing a mixture of enriched and SSZ mantle. (5) Type II5 lava has MORB-like REE patterns, and Nb/Yb and Th/Yb ratios. Based on field structural data, and the contemporaneity of the Baogutu adakite, a high-Mg diorite dike and the Miaoergou charnockite, these enriched and depleted magmatic features suggest generation in an intra-oceanic subduction zone influenced by ridge-trench interaction. The Altaids in Western Junggar are characterized by multiple intra-oceanic subduction systems, which may have continued to operate to the late

  7. Discovery and Genetic Mechanism of Basic Granulite in the Altay Orogenic Belt, Xinjiang, NW China

    Institute of Scientific and Technical Information of China (English)

    LI Zilong; CHEN Hanlin; YANG Shufeng; DONG Chuanwan; XIAO Wenjiao; LI Jiliang; YE Ying; WANG Jian

    2004-01-01

    Altay granulite (AG), which represents the product of high-grade metamorphism in the lower crust, was newly found in thc Wuqiagou area, Fuyun County in the Altay orogenic belt, Northwest China. It is composed mainly of hypersthene, augite, basic plagioclase, amphibole and brown biotite. Its mineral compositions of amphibole and biotite are rich in Mg/(Mg+Fe2+) and Ti. Geochemically, the AG is enriched in Mg/(Mg+Fe2+) and A12O3, and poor in CaO, with depletion of U, Th, K and Rb contents. Furthermore, geochemical data reflect that the protolith of the AG is igneousgenetic calc-alkalinc basalt formed under an island arc environment. The AG has ∑REE of 92.38-96.58 ppm and enriched LREE model with weak positive Eu anomaly of 1.09-1.15. In the MORB normalized spider diagram, the AG shows tridoming pattern with a strong negative Nb anomaly and medium negative P and Ti anomalies, reflecting that the AG has tectonic relation with subduction or subduction-related materials. The P-Tconditions of peak metamorphism of the AG arc 750-780°C and >0.6-0.7 GPa. Retrograde metamorphism implies that the protolith of the Altay granulite might undergo a metamorphic process along a clockwise P-T trajectory. Thereforc, thc formation and evolution of thc AG may have a genetic association with continental collision/orogeny and the AG was taken into the Late Paleozoic meta-strata by way of tectonic emplacement.

  8. 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.

  9. NEW OUTCROP AND SUBSURFACE DATA IN THE TERTIARY PIEDMONT BASIN (NW-ITALY: UNCONFORMITY-BOUNDED STRATIGRAPHIC UNITS AND THEIR RELATIONSHIPS WITH BASIN-MODIFICATION PHASES

    Directory of Open Access Journals (Sweden)

    MASSIMO ROSSI

    2009-11-01

    Full Text Available This paper deals with the regional stratigraphy around the Alps-Apennines junction during late Eocene-Miocene. The basin-fill architecture and its relation to changes in structural style were deciphered through the integration of subsurface and outcrop data on the basis of seismic- and sequence-stratigraphy principles, respectively.During late Eocene-Oligocene, the study area hosted a mosaic of partially interconnected sub-basins, and the Torino Hill area marked the junction towards the western apex of the Southern Alps foredeep (Gonfolite Basin. Since the latest Oligocene, the uplift of the north-verging Monferrato arc provided the separation from the adjacent Gonfolite Basin and the Tertiary Piedmont Basin behaved as a larger and more regularly subsiding thrust-top basin.The upper Eocene-Miocene successions record a long-term, major transgressive-regressive cycle, consisting of seven large-scale unconformity-bounded stratigraphic units, whose stacking pattern was controlled by changes in the rate of tectonic subsidence and whose boundaries were generated by basin-modification phases. During the Oligocene-lower Miocene deepening-upward sequence set, the marginal marine systems show a marked diachronism associated with  the SW-ward change of coastal onlap, punctuated by drowning-platform unconformities generated in relation to basinward tilting and high-angle synsedimentary faults.  The maximum transgression coincides with the late Burdigalian tectonic space creation phase, when a basinwide, highly efficient turbidite system was deposited. The middle-upper Miocene progradation, punctuated by forced regression pulses, was driven by the inversion and uplift of the southern basin margin, so that a northward shift and progressive narrowing of the turbidite depocentre occurred. 

  10. Hydrological behaviour of microbiotic crusts on sand dunes of NW China: Experimental evidences and numerical simulations

    Science.gov (United States)

    Wang, Xin Ping; Tedeschi, Anna; Orefice, Nadia; de Mascellis, Roberto; Menenti, Massimo

    2010-05-01

    Large ecological engineering projects were established to reduce and combat the hazards of sandstorms and desertification in northern China. An experiment to evaluate the effects of dunes stabilization by vegetation was carried out at Shapotou in Ningxia Hui Autonomous Region at the southeast edge of the Tengger Desert using xerophyte shrubs (Caragana korshinskii, Hedysarum scoparium and Artemisia ordosica) planted in straw checkerboard plots in 1956, 1964, 1981, 1987, 1998, and 2002. The fixed sand surface led to the formation of biotic soil crusts. Biotic crusts formed at the soil surface in the interspaces between shrubs and contribute to stabilization of soil surfaces. Previous results on the area have showed that: i) straw checkerboards enhance the capacity of the dune system to trap dust, leading to the accumulation of soil organic matter and nutrients; ii) the longer the period of dune stabilization, the greater the soil clay content in the shallow soil profile (0-5 cm), and greater the fractal dimension of soil particle size distribution. Benefit apart, one should be aware that the formation of a crusted layer at the soil surface is generally characterized by an altered pore-size distribution, with a frequent decrease of hydraulic conductivity which can induce changes of the water regime of the whole soil profile. Accordingly, the main objective of the paper is to evaluate the equivalent (from a hydraulic point of view) geometry of the crusted layer and to verify if the specific characteristics of the crusted soil layer, although local by nature, affect the hydrological behaviour of the whole soil profile. In fact, it is expected that, due to the formation of an upper, impeding soil layer, the lower soil layers do not reach saturation. Such behaviour has important consequences on both water flow and storages in soils. The final aim will be to understand how the crust at the surface of the artificially stabilized sand dune affects the infiltration capacity

  11. 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.

  12. Geochemical and isotopic approach to maturity/source/mixing estimations for natural gas and associated condensates in the Thrace Basin, NW Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Guergey, Kadir [University of Pamukkale, Geological Engineering Department, Kinikli Campus, 20070 Denizli (Turkey)]. E-mail: kgurgey@pamukkale.edu.tr; Philp, R. Paul [Geology and Geophysics, University of Oklahoma, Norman, OK 73019 (United States); Clayton, Chris [High Bank House, Eardiston, Tenbury Wells, Worcestershire, WR15 8JJ (United Kingdom); Emiroglu, Hasan [Turkish Petroleum Corporation, Exploration Group, Soeguetoezue, Ankara (Turkey); Siyako, Muzaffer [Turkish Petroleum Corporation, Exploration Group, Soeguetoezue, Ankara (Turkey)

    2005-11-15

    The Tertiary Thrace Basin located in NW Turkey comprises 9 km of clastic-sedimentary column ranging in age from Early Eocene to Recent in age. Fifteen natural gas and 10 associated condensate samples collected from the 11 different gas fields along the NW-SE extending zone of the northern portion of the basin were evaluated on the basis of their chemical and individual C isotopic compositions. For the purpose of the study, the genesis of CH{sub 4}, thermogenic C{sub 2+} gases, and associated condensates were evaluated separately. Methane appears to have 3 origins: Group-1 CH{sub 4} is bacteriogenic (Calculated {delta} {sup 13}C{sub C1-C} = -61.48%o; Silivri Field) and found in Oligocene reservoirs and mixed with the thermogenic Group-2 CH{sub 4}. They probably formed in the Upper Oligocene coal and shales deposited in a marshy-swamp environment of fluvio-deltaic settings. Group-2 ({delta} {sup 13}C{sub C1-C} = -35.80%o; Hamitabat Field) and Group-3 ({delta} {sup 13}C{sub 1-C} = -49.10%o; Degirmenkoey Field) methanes are thermogenic and share the same origin with the Group-2 and Group-3 C{sub 2+} gases. The Group-2 C{sub 2+} gases include 63% of the gas fields. They are produced from both Eocene (overwhelmingly) and Oligocene reservoirs. These gases were almost certainly generated from isotopically heavy terrestrial kerogen ({delta} {sup 13}C = -21%o) present in the Eocene deltaic Hamitabat shales. The Group-3 C{sub 2+} gases, produced from one field, were generated from isotopically light marine kerogen ({delta} {sup 13}C = -29%o). Lower Oligoce ne Mezardere shales deposited in pro-deltaic settings are believed to be the source of these gases. The bulk and individual n-alkane isotopic relationships between the rock extracts, gases, condensates and oils from the basin differentiated two Groups of condensates, which can be genetically linked to the Group-2 and -3 thermogenic C{sub 2+} gases. However, it is crucial to note that condensates do not necessarily correlate

  13. Petrogenesis and tectonic implications of the Early Carboniferous to the Late Permian Barleik plutons in the West Junggar (NW China)

    Science.gov (United States)

    Liu, Bo; Han, Bao-Fu; Ren, Rong; Chen, Jia-Fu; Wang, Zeng-Zhen; Zheng, Bo

    2017-02-01

    The Paleozoic accretionary orogenesis and continental crustal growth in Central Asia are thought to have close relationship with the evolution of the Paleo-Asian Ocean (PAO). The well-exposed plutons in the northern Barleik Mountains of the West Junggar region, NW China, may provide essential insights into the evolution of the Junggar Ocean, a branch of the PAO, and mechanism of continental crustal growth. Our work on the Barleik plutons indicates an early suite of 324-320 Ma diorite and a late suite of 314-259 Ma quartz syenite and granitic porphyry. All the plutons are characterized by high-K calc-alkaline to shoshonitic signatures, varying depletion in Nb, Ta, Sr, P, Eu, and Ti, low initial 87Sr/86Sr ratios (0.70241-0.70585), strongly positive εNd(t) values (+ 5.7-+7.7), and young one-stage Nd model ages (390-761 Ma), suggesting that they resulted from different batches of magma that were produced by fractional crystallization of a metasomatized mantle source with minor crustal contamination. The diorite is coeval with the youngest arc magmatic rocks, indicating a subduction-related origin. By contrast, the quartz syenite and granitic porphyry are geochemically similar to A2-type granites, with high Zr, Ga, and FeOT/[FeOT + MgO], and are coeval with the widespread plutons in the West Junggar. This, together with the occurrence of Late Carboniferous fluvial deposits and the lack of < 320 Ma ophiolitic and subduction-related metamorphic lithologies, definitively indicates a post-collisional setting after the closure of the Junggar Ocean. Slab breakoff accompanied by asthenospheric upwelling and basaltic underplating is a possible geodynamic process that is responsible for the post-collisional magmatism and vertical crustal growth in the region. Thus a tectonic switch from subduction to post-collision started at the end of the Early Carboniferous ( 320 Ma), probably as a result of the final closure of the Junggar Ocean.

  14. Petrogenesis and tectonic implications of Permian post-collisional granitoids in the Chinese southwestern Tianshan, NW China

    Science.gov (United States)

    Xia, Bin; Zhang, Lifei; Zhang, Lu

    2016-11-01

    Permian porphyritic granite and leucogranite from the Kekesu and Muzhaerte Valleys in the southwestern (SW) Tianshan orogenic belt, NW China have been studied to decipher their petrogenesis and tectonic implications. For porphyritic granite in the Kekesu Valley, in situ LA-ICPMS zircon U-Pb dating yields crystallization ages of 295-291 Ma. The granite is a high potassic calc-alkaline, slightly peraluminous type, enriched in large ion lithosphere elements (LILE) and light rare earth elements (LREE), but depleted in high field strength elements (HFSE). Zircon Hf isotopic analysis (zircon εHf(t) of -5.8 to -0.2, two-stage Hf model ages of 1323-1680 Ma) and Ti-in-zircon thermometry, which yields crystallization temperatures of 744-749 °C, indicate the parent magma was likely formed by partial melting of a Mesoproterozoic crustal source. By contrast, leucogranite in the Kekesu valley yields crystallization ages of 274-267 Ma. It contains muscovite and garnet, has high silicon and potassium, and is strongly peraluminous. Multiple inherited zircon cores and low zircon crystallization temperatures (687-701 °C), combined with negative zircon εHf(t) values (-7.0 to -4.0), indicate its parent magma was sourced from supracrustal metasedimentary rocks by muscovite-breakdown partial melting. In the Muzhaerte Valley, porphyritic granite has similar major and trace elements characteristics to the Kekesu porphyritic granite. However, its higher zircon εHf(t) values (-0.9 to +3.8) and corresponding lower two-stage Hf model ages (1070-1367 Ma) indicate that the parent magma likely included an input from a more juvenile mantle source. Ti-in-zircon thermometry gives lower crystallization temperature of ∼705 °C. The intrusive relationships between the Permian granitoids and Paleozoic arc plutons, and the LP-HT and (U)HP metamorphic belts, combined with geochronological studies, suggest that these Permian granitoids were generated in a post-collisional environment. It is

  15. 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.

  16. Organic geochemistry of oils and condensates in the Kekeya field, southwest depression of the Tarim Basin (China)

    Energy Technology Data Exchange (ETDEWEB)

    Maowen Li; Snowdon, L.R. [Geological Survey of Canada, Calgary (Canada); Renzi Lin; Peirong Wang [Jianghan Petroleum Institute, Hubei (China); Yongsheng Liao; Peilong Li [Shengli Petroleum Administrative Bureau, Shandong (China)

    1999-07-01

    This study shows that the oils and condensates in the Kekeya Field in the Tarim Basin, NW China, belong to a single family, most likely derived from marine shale source rocks deposited under oxic-suboxic conditions with mixed terrigenous and algal-bacterial organic inputs. The maturity data clearly indicate that the paraffinic condensates were not formed by thermal cracking of oil during late catagenesis (R{sub o} > 1.2%). Both the oils and condensates were generated within the normal oil window, whereas addition of gaseous hydrocarbons from a separate source resulted in migration fractionation and hence spuriously high heptane indices. Age specific biomarkers show that the oils and condensates were not generated from the Mesozoic-Cenozoic strata, but from the Carboniferous-Permian sections. 1D basin modelling results are consistent with this interpretation, suggesting that the Mesozoic-Eocene strata are currently immature with respect to hydrocarbon generation and expulsion. Deep-seated faults may have provided routes for upward fluid migration at the time of active deformation during several pulses of the Himalayan orogeny. The favoured targets for further petroleum exploration in front of the Kunlun Mountains include the deep structures within the Carboniferous-Permian strata for indigenous petroleum accumulations and anticlines and stratigraphic traps within the Mesozoic-Cenozoic sections that are cut by deep-seated thrust faults where secondary petroleum accumulations most likely occurred. (author)

  17. Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran

    Energy Technology Data Exchange (ETDEWEB)

    Omidvar, M.; Safari, A.; Vaziri-Moghaddam, H.; Ghalavand, H.

    2016-07-01

    Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers. (Author)

  18. Neogene magnetostratigraphy and rock magnetic study of the Kashi Depression, NW China: Implications to neotectonics in the SW Tianshan Mountains

    Science.gov (United States)

    Qiao, Qingqing; Huang, Baochun; Piper, John D. A.; Deng, Tao; Liu, Chengying

    2016-03-01

    The southwest Tianshan Mountains of China are bordered by the Tarim foreland and comprise an actively deforming segment of the India-Asia collisional system. We report a detailed magnetostratigraphic study of the Dashankou section in the Kashi Depression of the Tarim Basin to improve the understanding of the history of sedimentation, denudation, and mountain building in this region. The preferred correlation of the succession with the geomagnetic polarity timescale defines a depositional history between 12.4 and 3.0 Ma with a substantial increase in sedimentation rates identified at ~6.7 Ma corresponding to a pulse of rapid uplift in the southwest Tianshan Mountains. Although climatic changes may have modulated the record during Neogene times, they do not appear to have had an important influence on sediment accumulation rates between 7.0 and 2.6 Ma. Magnetic fabrics identify the influence of a regional stress field imparted by ongoing India-Asia collision in the lower part of the succession contrasting with predominantly sedimentary fabrics in the higher part of the succession. A major clastic influx with a maximum age estimate of ~3.6 Ma comprises the Xiyu conglomerates, and integration with other magnetostratigraphic investigations around the Tianshan demonstrates unambiguously that depositional onset of this coarse clastic episode is diachronous. Hence, the Xiyu Formation cannot be considered as a chronostratigraphic marker related to any specific tectonic or climatic event.

  19. 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.

  20. Paleoenvironmental reconstruction of the late Cenozoic Qaidam Basin, China

    Science.gov (United States)

    Zhang, C.; Wang, Y.; Li, Q.; Wang, X.; Deng, T.; Tseng, Z. J.; Takeuchi, G.; Xie, G.; Xu, Y.

    2011-12-01

    Reconstruction of paleoenvironments in the Tibetan region is important to understanding the linkage between tectonic force and climate change. Here we report new isotope data from the Qaidam Basin, China, which is located on the northeastern Tibetan Plateau, including stable C and O isotope analyses of a wide variety of late Cenozoic mammalian tooth enamel samples (including deer, giraffe, horse, rhino, and elephant), and O isotope compositions of phosphate (δ18Op) in fish bone samples. Mammalian tooth enamel δ13C values, when combined with fossil assemblage and other geological evidence, indicate that the Qaidam Basin was warmer and more humid during the late Miocene and early Pliocene, and that there was lush C3 vegetation with significant C4 components at that time, although the C4 plants were not consistently utilized. In contrast, the modern Qaidam Basin is dominated by C3 plants. Fish bone δ18Op values showed statistically significant enrichment from the Tuxi-Shengou-Naoge interval (late Miocene) to the Yahu interval (early Pliocene) and from the Yahu interval to the present day. This most likely reflects increases in the δ18O of lake water over time, as a result of increased aridification of the Qaidam Basin. Assuming that mammals drank exclusively from the lake, temperatures were calculated from average δ18Op values and average δ18Ow derived from large mammal tooth enamel δ18O. Temperatures were also estimated from δ18Op and δ18Ow estimated from co-ocurring large mammal tooth enamel δ18O. The temperature estimates were all lower than the average temperature of the modern Qinghai Lake surface water during the summer, and mostly too low to be reasonable, indicating that the fish and the large mammals were not in equilibrium with the same water. Assuming the relationship between salinity and δ18Ow observed for the modern Qinghai Lake and its surrounding lakes and ponds applied in the past, we calculated the paleosalinities of lake waters to be ~0 to

  1. 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.

  2. Quantification of Climate Changes and Human Activities That Impact Runoff in the Taihu Lake Basin, China

    OpenAIRE

    Dingzhi Peng; Linghua Qiu; Jing Fang; Zhongyuan Zhang

    2016-01-01

    Although a fragile climate region, the Taihu Lake Basin is among the most developed regions in China and is subjected to intense anthropogenic interference. In this basin, water resources encounter major challenges (e.g., floods, typhoons, and water pollution). In this study, the impacts of climate changes and human activities on hydrological processes were estimated to aid water resource management in developed regions in China. The Mann-Kendall test and cumulative anomaly curve were applied...

  3. Large-scale avulsion of the late Quaternary Sutlej river in the NW Indo-Gangetic foreland basin

    Science.gov (United States)

    Singh, Ajit; Gupta, Sanjeev; Sinha, Rajiv; Carter, Andrew; Thomsen, Kristina J.; Mark, Darren F.; Buylaert, Jan-Pieter; Mason, Philippa J.; Murray, Andrew S.; Jain, Mayank; Paul, Debajyoti

    2015-04-01

    River avulsions are important processes in the spatial evolution of river systems in tectonically active sedimentary basins as they govern large-scale patterns of sediment routing. However, the pattern and timing of avulsions in large river systems are poorly documented and not well understood. Here we document late Quaternary paleo-river channel changes in the Indo-Gangetic basin of northwest India. Using a combination of satellite remote sensing and detailed sediment coring, we analyse the large-scale planform geometry, and detailed sedimentary and stratigraphic nature of a major fluvial sedimentary deposit in the shallow subsurface. This sediment body records aggradation of multiple fluvial channel fills. Satellite remote sensing analysis indicates the trace of the buried channel complex and demonstrates that it exists in region of the Himalayan foreland where no major rivers are currently present. Thus it records the former drainage pathway of a major river, which has since been diverted. We use optically stimulated luminescence dating techniques to develop an age model for the stratigraphic succession and hence constrain the timing of river channel existence and diversion. Provenance analysis based on U-Pb dating of detrital zircons and detrital mica Ar-Ar ages indicate sediment sources in the Higher Himalayan Crystalline and Lesser Himalayan Crystalline Series indicating that this paleo-river channel system formed a major perennial river derived from the main body of the Himalaya. Specifically we are able to fingerprint bedrock sources in the catchment of the present-day Sutlej river indicating that the paleo-fluvial system represents the former course of the Sutlej river prior to a major nodal avulsion to its present day course. Our results indicate that on geologically relatively short time-scales, we observe dramatic along strike shifts in the location of major Himalayan rivers. Our sediment records when combined with high-resolution dating and

  4. Tectono-thermal modeling of the Yinggehai Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    HE; Lijuan

    2001-01-01

    [1]Li Yuliang, Huang Zhongming, Thermal history about northern margin of South China Sea, China Offshore Oil and Gas (Geology) (in Chinese), 1990, 4(6): 31.[2]Li Yuliang, Zhang Quanxing, Zhang Qiming, Thermal abnormality of Ya13-1 gas field, China Offshore Oil and Gas (Geology) (in Chinese), 1992, 6(5): 33.[3]Gong Zaisheng, Li Sitian et al., Basin Analysis and Accumulation of Oil and Gas in Northern Margin of South China Sea (in Chinese), Beijing: Science Press, 1997.[4]He Lijuan, Xiong Liangping, Wang Jiyang et al., Calculation of stretching factors in the multi-phase modeling of sedimentary basins, Chinese Science Bulletin (in Chinese), 1995, 40(24): 2261.[5]He Lijuan, Xiong Liangping, Wang Jiyang, Effects on the tectono-thermal modeling of extensional basins, Scientia Geologica Sinica (in Chinese), 1998, 33(2): 222.[6]Pitman, W. C., Andrews, J. A., Subsidence and thermal history of small pull-apart basins, in Strike-slip Deformation, Basin Formation and Sedimentation (eds. Kevin, T. B., Nicholas, C. B.), Society of Economic Paleontologists and Mineralogists, Special Publication, 1985.[7]Zhang Qiming, Hu Zhongliang, High-temperature and high-pressure conditions and migration of hydrocarbons in Yinggehai-Qiongdongnan basin, A Collection on Petroleum Geology of Yinggehai Basin, South China Sea (in Chinese), Beijing: Seismology Press, 1993, 78-84.

  5. Response to "No major active backthrust bounds the Pir Panjal Range near Kashmir basin, NW Himalaya" by Shah

    Science.gov (United States)

    Dar, Reyaz Ahmad; Romshoo, Shakil Ahmad; Chandra, Rakesh; Ahmad, Ishtiaq

    2016-06-01

    This article presents a rebuttal to the entirely ambiguous and unwanted commentary made by Shah (JAES-D-15-00980) on Dar et al. (2014). The original article was aimed to evaluate the tectono-geomorphic evolution of the Kashmir Valley using geomorphic indices obtained from satellite images and detailed fieldwork. However, Shah while deviating from the core of the article has attempted to build an inexplicable tale about the structural configuration of the region. The comment is primarily based on the misinterpretation regarding the dip direction of a thrust fault. Pertinently, no major ∼SW dipping frontal fault bounding the Pir Panjal Range near Kashmir Valley is shown in the paper by Dar et al. (2014). The commentator has just recycled already documented text pertaining to general tectonic character of a few ∼NE dipping thrusts i.e., the Main Frontal Thrust (MFT) and Raisi Fault (RF). Moreover, some unknown structure named as Kashmir Basin Fault (KBF) by the commentator has been discussed, which does not even exist in the region. The commentary on the whole actually does not relate with the investigation reported by Dar et al. (2014), hence merits no consideration for publication.

  6. Cyclostratigraphy of Uppermost Carboniferous-to-Lower Triassic Terrestrial Deposits in Bogda Mountains, NW China - A Potential Astrostratigraphic Proxy Section

    Science.gov (United States)

    Yang, W.; Tabor, N. J.; Crowley, J. L.; Miggins, D. P.; Obrist, J.

    2012-12-01

    Lithologic and stratigraphic evidence from the uppermost Carboniferous-Lower Triassic fluvial-lacustrine deposits in the Tarlong-Taodonggou half-graben of southern Bogda Mountains, NW China shows 3 orders of depositional cyclicity. The section is thick (~1,700 m), relatively complete, and well-constrained by radiometric ages, as a potential candidate for Permo-Triassic astrostratigraphy in the mid-latitude of NE Pangea. 10 low-order cycles (LCs) are defined by their dominant depositional environments and prominent cycle boundaries. Upper Gzhelian-mid Sakamarian Lower, Middle, and Upper Daheyan LCs are composed mainly of meandering and braided stream deposits, formed during initial and early rifting. The Upper Daheyan LC contains mature Calcisols, indicating a subhumid-semi-arid climatic change. They were transgressed conformably by lake-margin, deltaic, and profundal deposits of the mid-Sakamarian-Artinskian Lucaogou and Hongyanchi LCs, indicating rapid graben subsidence. Contrasting lithologies suggest highly-fluctuating arid-subhumid conditions at the intermediate and high-order cycle scales. The two LCs are separated by a fluvial-incision and correlative deltaic downlap surface, indicating an uplifting event. Lake regression and fluvial peneplanation at the end of Hongyanchi LC is indicated by fluvial erosion and deposition of the thin (1-10s m) Lower Quanzijie LC, suggesting a tectonic uplift and/or climatic change. The basal two mature Calcisols and top Gleysols of the Upper Quanzijie LC containing fluvial and loess (?) deposits indicate an arid-to-humid climatic change. The two Quanzijie LCs span over Kungurian (?)-Capitanian ages and signify the beginning of late rifting. The humid condition magnified in overlying thick (~800 m) Lopingian-lower Induan Wutonggou LC, composed of deltaic, lake-margin, and meandering stream deposits. The overlying fluvial-lake margin deposits of the Induan Jiucaiyuan LC indicate a combination of tectonic uplift and a climatic

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. Magnetic properties contribution to the identification and provenance of marine sediments: distal IRD in the Galicia Interior Basin (NW Spain)

    Science.gov (United States)

    Plaza-Morlote, Maider; Rey, Daniel; Francisco Santos, Jose; Ribeiro, Sara; Bernabeu, Ana; Mohamed, Kais; Heslop, David; Rubio, Belén; Martins, Virginia

    2016-04-01

    This paper discusses the advantages of using a combined environmagnetic and geochemical approach to the provenance and characterization of distal IRDs occurring during the Last Glacial Period in core CI12PC3 from the Galicia Interior Basin (GIB). Six Heinrich layers (HL1-6) have been identified in the area in base to the detection of distinct populations of exotic magnetic mineral assemblages alien to the local/regional sedimentation environment. Their extension has been determined by Ca/Sr and Si/Sr ratios and their provenance by 143Nd/144Nd and 87Sr/86Sr isotopic ratios and FORCs. The sedimentary expression of HL is characterized by the presence of distal Ice Rafted Detritus (IRD). Distal IRD magnetic signatures in the GIB consist of (i) an increase of one order of magnitude in the peak amplitude of magnetic susceptibility from background values, (ii) a general coarsening of the magnetic grain size in a mineral assemblage dominated by titano-magnetites, (iii) FORC distributions pushing towards the coarse MD or PSD component, and (iv) thermomagnetic curves depicting the occurrence of several magnetite phases. These four features are very different from the fine-grained biogenic magnetic assemblages characterized by the combination of lower MS and higher coercivity values that dominate the predominant mixtures of the non-interacting SSD and PSD components in the non-IRD influenced background sedimentation. Our results show that the last 70.000 yr of sedimentation in the GIB were controlled by the relative contribution of local detrital material derived from the Iberian Variscan Chain and IRD alien material from the iceberg melting during the Heinrich Events. They also show two main IRD provenance fields: Europe and Canada. And that the later is more important for for HL1, HL2, HL4 and HL5. FORCs analysis complemented the isotopic information and provided a very unique information, indicating that glacial flour may not always have the same provenance as IRD and that

  12. 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.

  13. 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.

  14. Thallium distribution in sediments from the Pearl river basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juan [Guangzhou University, Key Laboratory of Waters Safety and Protection in the Pearl River Delta, Ministry of Education, Guangzhou (China); Forschungszentrum Dresden-Rossendorf (FZD), Institute of Radiochemistry, Research Site Leipzig, Leipzig (Germany); Wang, Jin; Chen, Yongheng [Guangzhou University, Key Laboratory of Waters Safety and Protection in the Pearl River Delta, Ministry of Education, Guangzhou (China); Qi, Jianying [Department of Environmental Science and Engineering, Guangzhou University, Guangzhou (China); Lippold, Holger [Forschungszentrum Dresden-Rossendorf (FZD), Institute of Radiochemistry, Research Site Leipzig, Leipzig (Germany); Wang, Chunlin [Guangdong Provincial Academy of Environmental Science, Guangzhou (China)

    2010-10-15

    Thallium (Tl) is a rare element of high toxicity. Sediments sampled in three representative locations near industries utilizing Tl-containing raw materials from the Pearl River Basin, China were analyzed for their total Tl contents and the Tl contents in four sequentially extracted fractions (i.e., weak acid exchangeable, reducible, oxidizable, and residual fraction). The results reveal that the total Tl contents (1.25-19.1 {mu}g/g) in the studied sediments were slightly high to quite high compared with those in the Chinese background sediments. This indicates the apparent Tl contamination of the investigated sediments. However, with respect to the chemical fractions, Tl is mainly associated with the residual fraction (>60%) of the sediments, especially of those from the mining area of Tl-bearing pyrite minerals, indicating the relatively low mobility, and low bioavailability of Tl in these sediments. This obviously contrasts with the previous findings that Tl is mainly entrapped in the first three labile fractions of the contaminated samples. Possible reasons were given for the dominating association of Tl with the residual fraction (>95%) of the mining area sediments. The significant role of certain K-containing silicates or minerals of these sediments on retaining Tl in the residual fraction, discovered by this study, provides a special field of research opportunity for the Tl-containing wastewater treatment. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. 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.

  16. Lithostratigraphic description, sedimentological characteristics and depositional environments of rocks penetrated by Illela borehole, Sokoto Basin, NW Nigeria: A connection between Gulf of Guinea Basins

    Science.gov (United States)

    Toyin, A.; Adekeye, O. A.; Bale, R. B.; Sanni, Z. J.; Jimoh, O. A.

    2016-09-01

    The basal unit of the succession in the Illela borehole belongs to the Dange Formation comprising thick calcareous and variably coloured dark-greyish shale of 36.30 m thick which is overlain by a 31.44 m thick limestone of Kalambaina Formation with 1.7 m thick shaly-limestone inclusive. The uppermost part of the section belongs to the Gwandu Formation which has intercalation of silty-clay, muddy siltstones with well lithified ironstone capping the borehole section. The limestone/carbonate microfacie as deduced from their salient lithologic, sedimentologic and paleontologic features are comparable to standard microfacie (SMF) types 9 and 10, i.e. bioclastic wackestone/bioclastic micrite and packstone-wackestone respectively. Diagenetically, syndepositional and early diagenesis have taken place particularly cementation and replacement in the carbonate rocks and these have greatly affected the reservoir potential negatively. The matrix/grain relationships indicate a shallow marine environment of deposition. The borehole section is delineated into upper foraminifera and lower ostracod biostratigraphic units as no formal biostratigraphic zonation could be attempted due to low diversity of both benthic foraminifera, marine ostracods and the absence of planktonic foraminifera. The similarity of the ostracod assemblages between this study area, Illela borehole, West Africa, North Africa (Libya), Mali and Niger Republic) and South-Western Nigeria (West Africa) suggests that a marine connection exists between the Gulf of Guinea and the Sokoto Basin via the area occupied by the River Niger during the Paleocene.

  17. Pollen and phytoliths from fired ancient potsherds as potential indicators for deciphering past vegetation and climate in Turpan, Xinjiang, NW China.

    Science.gov (United States)

    Yao, Yi-Feng; Li, Xiao; Jiang, Hong-En; Ferguson, David K; Hueber, Francis; Ghosh, Ruby; Bera, Subir; Li, Cheng-Sen

    2012-01-01

    It is demonstrated that palynomorphs can occur in fired ancient potsherds when the firing temperature was under 350°C. Pollen and phytoliths recovered from incompletely fired and fully fired potsherds (ca. 2700 yrs BP) from the Yanghai Tombs, Turpan, Xinjiang, NW China can be used as potential indicators for reconstructing past vegetation and corresponding climate in the area. The results show a higher rate of recovery of pollen and phytoliths from incompletely fired potsherds than from fully fired ones. Charred phytoliths recovered from both fully fired and incompletely fired potsherds prove that degree and condition of firing result in a permanent change in phytolith color. The palynological data, together with previous data of macrobotanical remains from the Yanghai Tombs, suggest that temperate vegetation and arid climatic conditions dominated in the area ca. 2700 yrs BP.

  18. Pollen and phytoliths from fired ancient potsherds as potential indicators for deciphering past vegetation and climate in Turpan, Xinjiang, NW China.

    Directory of Open Access Journals (Sweden)

    Yi-Feng Yao

    Full Text Available It is demonstrated that palynomorphs can occur in fired ancient potsherds when the firing temperature was under 350°C. Pollen and phytoliths recovered from incompletely fired and fully fired potsherds (ca. 2700 yrs BP from the Yanghai Tombs, Turpan, Xinjiang, NW China can be used as potential indicators for reconstructing past vegetation and corresponding climate in the area. The results show a higher rate of recovery of pollen and phytoliths from incompletely fired potsherds than from fully fired ones. Charred phytoliths recovered from both fully fired and incompletely fired potsherds prove that degree and condition of firing result in a permanent change in phytolith color. The palynological data, together with previous data of macrobotanical remains from the Yanghai Tombs, suggest that temperate vegetation and arid climatic conditions dominated in the area ca. 2700 yrs BP.

  19. 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.

  20. Extension structural records in the Qinshui basin (North China) since the Late Mesozoic

    Science.gov (United States)

    Wang, Ying; Zhang, Qinglong; Zhu, Wenbin; Wang, Liangshu; Xie, Guoai; Liu, Chao; Zou, Xu

    2014-11-01

    Qinshui basin has abundant coal-bed methane resources and has been undergoing intensive intracontinental rifting and extensional tectonics since the Late Mesozoic. Some fractures, which were previously considered as conjugate shear fractures, are interpreted as joint sets with extension characteristics, for the first time in the Qinshui basin. The widely distributed joint sets with stable attitudes can be divided into four sets. This paper presents updated results of fault-slip datasets collected in different zones of the Qinshui basin and addresses the changes in the direction of extensional stresses since the Late Mesozoic. Based on the analysis results of the slickenline of normal faults, joint sets in the field, and focal mechanism solutions data from the Shanxi Province, we identified four main directions of extension since the Late Mesozoic in the Qinshui basin: (1) Early Cenozoic ENE-WSW (85 ± 15°) extension; (2) Palaeogene NNE-SSW (30 ± 5°) extension; (3) Miocene NW-SE (135 ± 15°) extension; and (4) Late Pliocene-quaternary NNW-SSE (170 ± 5°) extension. The principal extension directions in the Qinshui basin seem to have undergone a counterclockwise rotation from the Early Cenozoic to the Miocene. We prefer that the extension deformation events in the Qinshui basin since the Late Mesozoic were mainly related to the back-arc spreading induced by westward subduction of the paleo-Pacific plate under the Eurasian continent.

  1. The influence of frozen soil change on water balance in the upper Yellow River Basin, China

    Science.gov (United States)

    Cuo, L.; Zhao, L.; Zhou, B.

    2013-12-01

    Yellow River supports 30% of China's population and 13% of China's total cultivated area. About 35% of the Yellow River discharge comes from the upper Yellow River Basin. Seasonally frozen, continuous and isolated permafrost soils coexist and cover the entire upper Yellow River Basin. The spatial distribution of various frozen soisl is primarily determined by the elevation in the basin. Since the past five decades, air temperature has increased by a rate of 0.03 C/year in the upper Yellow River Basin. Many studies reported the conversions of continuous to isolated permafrost soil, permafrost soil to seasonally frozen soil and the thickening of the active layer due to rising temperature in the basin. However, very few studies reported the impact of the change of frozen soil on the water balance in the basin. In this study, the Variable Infiltration Capacity (VIC) model is applied in the upper Yellow River Basin to study the change of frozen soil and its impact on the water balance. Soil temperature and soil liquid content measured up to 3 m below ground surface at a number of sites in the upper Yellow River Basin and the surroundings are used to evaluate the model simulation. Streamflow is also calibrated and validated using historical streamflow records. The validated VIC model is then used to investigate the frozen soil change and the impact of the change on water balance terms including surface runoff, baseflow, evapotranspiration, soil water content, and streamflow in the basin.

  2. 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.

  3. Structural features and petroleum geology of the fold-thrust belt in the southern Tarim basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xinyuan; LUO Jinhai; WANG Qinghua

    2004-01-01

    The west Kunlun fold-thrust belt (WKFTB) and the Altun fold-thrust belt (AFTB) are respectively located in the southern margin of the Tarim basin, NW China. The analyses of typical structures and regional dynamics of the fold-thrust belts reveal their different structural and petroleum features and mechanisms. WKFTB differs from AFTB by abundant fault-related folds and triangles zones, and was formed by northward extrusion of the west Kunlun orogen. AFTB was affected synchronously by northward extrusion of the Altun orogen and the sinistral strike-slipping of the Altun Fault, so it is characterized by the minor scale and the monotonous structural styles. The Aqike anticline and the Aqike fault, of which the strikes are orthogonal to the strike of the fold-thrust belts, are regarded as the adjustive structures between both of the fold-thrust belts. The oil-gas pools of WKFTB develop mainly in the faulted-related anticline traps, but the oil-gas pools of AFTB develop mainly in the low fault-block and anticlines traps related with the paleo-uplifts. There are different exploration countermeasures for both of the fold-thrust belts.

  4. 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.

  5. 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

  6. 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.

  7. Tectonic Fractures in Tight Gas Sandstones of the Upper Triassic Xujiahe Formation in the Western Sichuan Basin,China

    Institute of Scientific and Technical Information of China (English)

    ZENG Lianbo; LI Yuegang

    2010-01-01

    The western Sichuan Basin,which is located at the front of the Longmen Mountains in the west of Sichuan Province,China,is a foreland basin formed in the Late Triassic.The Upper Triassic Xujiahe Formation is a tight gas sandstone reservoir with low porosity and ultra-low permeability,whose gas accumulation and production are controlled by well-developed fracture zones.There are mainly three types of fractures developed in the Upper Triassic tight gas sandstones,namely tectonic fractures,diagenetic fractures and overpressure-related fractures,of which high-angle tectonic fractures are the most important.The tectonic fractures can be classified into four sets,i.e.,N-S-,NE-,E-W-and NW-striking fractures.In addition,there are a number of approximately horizontal shear fractures in some of the medium-grained sandstones and grit stones nearby the thrusts or slip layers.Tectonic fractures were mainly formed at the end of the Triassic,the end of the Cretaceous and the end of the Neogene-Early Pleistocene.The development degree of tectonic fractures was controlled by lithology,thickness,structure,stress and fluid pressure.Overpressure makes not only the rock shear strength decrease,but also the stress state change from compression to tension.Thus,tensional fractures can be formed in fold-thrust belts.Tectonic fractures are mainly developed along the NE-and N-S-striking structural belts,and are the important storage space and the principal flow channels in the tight gas sandstone.The porosity of fractures here is 28.4% of the gross reservoir porosity,and the permeability of fractures being two or three grades higher than that of the matrix pores.Four sets of high-angle tectonic fractures and horizontal shear fractures formed a good network system and controlled the distribution and production of gas in the tight sandstones.

  8. 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

  9. Vegetation Control in the Long-term Self-stabilisation of the Liangzhou Oasis of the Upper Shiyang River Watershed of West-central Gansu, NW China

    Science.gov (United States)

    Bourque, Charles; Hassan, Quazi

    2010-05-01

    Oases are special ecological systems that naturally oppose the encroachment of deserts by staying moist. Oases provide important habitat refugia for plants, animals, and humans alike. Oases in NW China account for only about 5% of the total land area of the region, but give shelter and feed about 95% of the area's growing population. It has been proposed by many scientists and observers of desertification in NW China that rapid economic development in the area is largely unsustainable and is occurring at the very detriment of the oases. This presentation explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River Watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (> 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis-water conditions in the USRW is based on an application of a process model of soil-water hydrology. The model is used to simulate long-term soil water content in the Liangzhou Oasis as a function of (i) monthly composites of MODIS images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms, and (iii) an 80-m resolution digital elevation model of the area. Modelled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapour from the land surface to the air, increasing the air's lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward in the watershed, leading to an overall reduction in soil water in the Liangzhou Oasis. Feedback mechanisms of oasis self-support introduced

  10. Ultrahigh pressure (>7 GPa) gneissic K-feldspar (-bearing) garnet clinopyroxenite in the Altyn Tagh, NW China: Evidence from clinopyroxene exsolution in garnet

    Institute of Scientific and Technical Information of China (English)

    LIU; Liang; CHEN; Danling; ZHANG; Anda; SUN; Yong; WANG; Ya

    2005-01-01

    The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume.The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmenite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate igneous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing Iherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deepsubduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western China.

  11. 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

  12. 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

  13. Discovery of Early Permian Reefs in Xichang Basin, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    Qin Jianxiong; Zeng Yunfu; Wu Yong

    1996-01-01

    @@ In 1992, Lower Permian reefs were found in various stratigraphic sections in such counties as Ganluo,Puge, and Butuo, in Xichang Basin. This discovery not only promotes the development of Lower Permain sedimentology in Xichang Basin, but also is of great significance for oil-gas exploration along the western margin of Yangtze platform.

  14. 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.

  15. 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.

  16. A double-cycle lake basin formed in extensional to transtensional setting: The Paleogene Nanpu Sag, Bohai Bay Basin, China

    Science.gov (United States)

    Zhang, Jianguo; Jiang, Zaixing; Gierlowski-Kordesch, Elizabeth; Xian, Benzhong; Li, Zhenpeng; Wang, Siqi; Wang, Xiabin

    2017-03-01

    It has been known that both extensional and transtensional tectonics commonly trigger a one-cycle evolution of lake sediments, but lake-cycle development co-controlled by extensional and transtensional tectonics still need identification. Here we report a double-cycle of lake sediments formed in extensional to transtensional phases in the Paleogene Nanpu Sag of the Bohai Bay Basin, China. The sag successively experienced five phases of lake-type evolution, characterized by: 1) overfilled, 2) balanced-fill, 3) overfilled, 4) balanced-fill, and 5) overfilled. Extensional tectonics was responsible for the opening of the basin and the initial creation of accommodation (1st through 3rd phase). Next, subsidence increased again through transtensional tectonics resulting in the creation of new accommodation (4th-5th phases). Investigations show this double-cycle lake-type evolution is also present in other lake-basins with similar tectonic settings (e.g., both extensional and transtensional tectonics). A different exploration and exploitation strategy should be devoted to the double-cycle evolution of lake basins controlled by extensional to transtensional tectonics in comparison to the single-cycle evolution in extensional or transtensional lake basins.

  17. Late Mesozoic basin and range tectonics and related magmatism in Southeast China

    Directory of Open Access Journals (Sweden)

    Dezi Wang

    2012-03-01

    Full Text Available During the Late Mesozoic Middle Jurassic–Late Cretaceous, basin and range tectonics and associated magmatism representative of an extensional tectonic setting was widespread in southeastern China as a result of Pacific Plate subduction. Basin tectonics consists of post-orogenic (Type I and intra-continental extensional basins (Type II. Type I basins developed in the piedmont and intraland during the Late Triassic to Early Jurassic, in which coarse-grained terrestrial clastic sediments were deposited. Type II basins formed during intra-continental crustal thinning and were characterized by the development of grabens and half-grabens. Graben basins were mainly generated during the Middle Jurassic and were associated with bimodal volcanism. Sediments in half-grabens are intercalated with rhyolitic tuffs and lavas and are Early Cretaceous in age with a dominance of Late Cretaceous–Paleogene red beds. Ranges are composed of granitoids and bimodal volcanic rocks, A-type granites and dome-type metamorphic core complexes. The authors analyzed lithological, geochemical and geochronological features of the Late Mesozoic igneous rock assemblages and proposed some geodynamical constraints on forming the basin and range tectonics of South China. A comparison of the similarities and differences of basin and range tectonics between the eastern and western shores of the Pacific is made, and the geodynamical evolution model of the Southeast China Block during Late Mesozoic is discussed. Studied results suggest that the basin and range terrane within South China developed on a pre-Mesozoic folded belt was derived from a polyphase tectonic evolution mainly constrained by subduction of the western Pacific Plate since the Late Mesozoic, leading to formation of various magmatism in a back-arc extensional setting. Its geodynamic mechanism can compare with that of basin and range tectonics in the eastern shore of the Pacific. Differences of basin and range

  18. 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.

  19. 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.

  20. Late Cenozoic sedimentary process and its response to the slip history of the central Altyn Tagh fault, NW China

    Institute of Scientific and Technical Information of China (English)

    陈正乐; 张岳桥; 陈宣华; 王小凤; A.S.Ramon; W.B.Zack

    2001-01-01

    The ENE-striking Altyn Tagh fault (ATF), extending along the northern edge of the Tibetan Plateau, is one of the major important strike-slip faults, and has been known as one of the key areas to debate the eastward extrusion and crustral shortening models of the Tibetan Plateau during and after India-Asia collision. This paper mainly presents new evidence of Late Cenozoic sedimentary process to reconstruct the slip history of the ATF during the Late Cenozoic. Field measurements and laboratory analyses of the sedimentary characteristics in the Late Cenozoic basins in the central Altyn Tagh fault suggest that Late Cenozoic sedimentary sequence should be divided into three units according to facies changes. The paleo-topography reconstruction shows that the sedimentation in these basins was tightly related with the fault, indicating that the ATF has experienced at least three stages of strike slipping in the Late Cenozoic. New geological data from the Late Cenozoic sedimentary basins and the formation of th

  1. 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.

  2. 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.

  3. 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.

  4. Magnetostratigraphic dating of the Huojiadi Paleolithic site in the Nihewan Basin, North China

    NARCIS (Netherlands)

    Liu, Ping; Deng, Chenglong; Li, Shihu; Zhu, Rixiang

    2010-01-01

    The fluvio-lacustrine sequences in the Nihewan Basin, northern China provide important terrestrial archives of paleoclimate and paleoenvironment as well as an important source of Paleolithic settlements and therefore early human occupation in the eastern Old World. Magnetostratigraphic dating of the

  5. Linking Tarim Basin sea retreat (west China) and Asian aridification in the late Eocene

    NARCIS (Netherlands)

    Bosboom, R.; Dupont-Nivet, G.; Grothe, A.; Brinkhuis, H.; Villa, G.; Mandic, O.; Stoica, M.; Huang, W.; Yang, W.; Guo, Z.; Krijgsman, W.

    2014-01-01

    The Tarim Basin in western China formed the easternmost margin of a shallow epicontinental sea that extended across Eurasia and was well connected to the western Tethys during the Paleogene. Climate modelling studies suggest that the westward retreat of this sea from Central Asia may have been as im

  6. Assessment of Permian tight oil and gas resources in the Junggar basin of China, 2016

    Science.gov (United States)

    Potter, Christopher J.; Schenk, Christopher J.; Tennyson, Marilyn E.; Klett, Timothy R.; Gaswirth, Stephanie B.; Leathers-Miller, Heidi M.; Finn, Thomas M.; Brownfield, Michael E.; Pitman, Janet K.; Mercier, Tracey J.; Le, Phuong A.; Drake, Ronald M.

    2017-04-05

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 764 million barrels of oil and 3.5 trillion cubic feet of gas in tight reservoirs in the Permian Lucaogou Formation in the Junggar basin of northwestern China.

  7. 水平井、氮气及降黏剂辅助蒸汽吞吐技术——以准噶尔盆地春风油田浅薄层超稠油为例%Horizontal well, nitrogen and viscosity reducer assisted steam huff and puff technology:Taking super heavy oil in shallow and thin beds, Chunfeng Oilfield, Junggar Basin,NW China, as an example

    Institute of Scientific and Technical Information of China (English)

    王学忠; 王金铸; 乔明全

    2013-01-01

    针对准噶尔盆地春风油田埋藏浅(400~570 m)、地层温度低(22~28℃)、储集层薄(2~6 m,平均3.5m)、地下原油黏度高(50000~90000 mPa·s)但热敏性好、适合热采的特点,提出了综合水平井、降黏剂、氮气、蒸汽的复合开发稠油方式(HDNS),并在排601砂体北部实施了HDNS开发先导试验.结果表明:油套环空注氮气,可起到隔热作用;利用氮气膨胀性高的特点,补充地层能量;地层内氮气向上超覆,对地层有保温作用.HDNS各要素的综合作用显著提高了蒸汽波及体积、驱油效率和原油流动能力,降低了原油黏度.春风油田应用HDNS技术已经建成产能40×104t,采油速度3.0%,实现了低品位浅薄层超稠油的高速高效开发.图2表6参19%Chunfeng Oilfield in the Junggar Basin has shallow burial depth (400-570 m), low formation temperature (22-28℃), thin reservoirs (2-6 m, averaging 3.5 m), high underground crude oil viscosity (50 000-90 000 mPa · s), but high sensitivity to heat, it is suitable for thermal recovery. In view of these features, a development method for this oilfield combining horizontal well, viscosity reducer, nitrogen and steam flooding (HDNS) was put forward, and pilot test was carried out in Northern Pai 601 sand body. The results show: injecting nitrogen through annulus can insulate thermal, high expansibility of nitrogen works to compensate formation energy, and nitrogen overlapping in reservoir has insulation effect. The combination effect of all parts of HDNS significantly increased steam sweep volume, oil displacement efficiency and crude oil flow ability, and reduced oil viscosity. Thanks to this technique, Chunfeng Oilfield has built up a production capacity of 40×104t, with an oil recovery rate of 3%, marking the successful high-speed and high-efficiency development of low-grade shallow thin super heavy oil.

  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 planning and disaster management for the Ordos Basin.

  9. Carboniferous rifted arcs leading to an archipelago of multiple arcs in the Beishan-Tianshan orogenic collages (NW China)

    Science.gov (United States)

    Tian, Zhonghua; Xiao, Wenjiao; Windley, Brian F.; Zhang, Ji'en; Zhang, Zhiyong; Song, Dongfang

    2016-12-01

    The Beishan and East Tianshan Orogenic Collages in the southernmost Central Asian Orogenic Belt (CAOB) record the final stages of evolution of the Paleo-Asian Ocean. These collages and their constituent arcs have an important significance for resolving current controversies regarding their tectonic setting and age, consequent accretionary history of the southern CAOB, and the closure time of the Paleo-Asian Ocean. In this paper, we present our work on the southern Mazongshan arc and the northern Hongyanjing Basin in the Beishan Orogenic Collage (BOC), and our comparison with the Bogda arc and associated basins in the East Tianshan Orogenic Collage. Field relationships indicate that the Pochengshan fault defines the boundary between the arc and basin in the BOC. Volcanic rocks including basalts and rhyolites in the Mazongshan arc have bimodal calc-alkaline characteristics, an enrichment in large ion lithophile elements such as Rb, Ba, and Pb and depletion in high field-strength elements (e.g., Nb and Ta), which were probably developed in a subduction-related tectonic setting. We suggest that these bimodal calc-alkaline volcanic rocks formed in rifted arcs instead of post-orogenic rifts with mantle plume inputs. By making detailed geochemical comparisons between the Mazongshan arc and the Bogda arc to the west, we further propose that they are similar and both formed in arc rifts, and helped generate a Carboniferous archipelago of multiple arcs in the southern Paleo-Asian Ocean. These data and ideas enable us to postulate a new model for the tectonic evolution of the southern CAOB.

  10. Geochemistry of fine-grained clastic rocks in the Mesoproterozoic Kawabulake Group: implications for provenance and the tectonic model of the Eastern Tianshan, Xinjiang, NW China

    Science.gov (United States)

    Li, Deng-Feng; Chen, Hua-Yong; Zhang, Li; Fralick, Philip; Hollings, Pete; Mi, Mei; Lu, Wan-Jian; Han, Jin-Sheng; Wang, Cheng-Ming; Fang, Jing

    2016-02-01

    The Mesoproterozoic Kawabulake Group, which is unconformably overlain by the Lower Cambrian Huangshan Formation and conformably overlies the Mesoproterozoic Xingxingxia Group in the Eastern Tianshan area, NW China, is comprised mainly of siltstone, slate, sandstone and phyllite. New geochemical data for the clastic rocks from the Kawabulake Group were investigated to constrain the provenance and weathering history of the source rocks, in order to evaluate the tectonic evolution of the Eastern Tianshan area. Kawabulake Group rocks are compositionally similar to PAAS (average Post-Archean Australian Shale), indicating derivation from a felsic source that is characterized by depletion in some HFSEs such as Nb, Ta and Ti. The Chemical Index of Alteration (CIA) for the sandstone, siltstone and slate samples (CIA = 60 on average) suggests intensely weathered sources. Light REE-enrichment patterns ((La/Yb)CN = 4-20) coupled with negative Eu anomalies (Eu/Eu* between 0.44 and 0.89 with an average of 0.62) are similar to those of PAAS, consistent with cratonic sources. The major and trace element compositions imply a dominantly Precambrian felsic source region with a minor contribution from mafic materials. The Sr-Nd isotopic compositions and the ages of T DM2 (~3.4, 2.5-1.8, 1.2 and 1.0 Ga) are consistent with the evolutionary history of Kuluketage in the northern Tarim, suggesting that the Tarim Craton was the main source area for the Kawabulake Group.

  11. Geochemistry of fine-grained clastic rocks in the Mesoproterozoic Kawabulake Group: implications for provenance and the tectonic model of the Eastern Tianshan, Xinjiang, NW China

    Science.gov (United States)

    Li, Deng-Feng; Chen, Hua-Yong; Zhang, Li; Fralick, Philip; Hollings, Pete; Mi, Mei; Lu, Wan-Jian; Han, Jin-Sheng; Wang, Cheng-Ming; Fang, Jing

    2017-01-01

    The Mesoproterozoic Kawabulake Group, which is unconformably overlain by the Lower Cambrian Huangshan Formation and conformably overlies the Mesoproterozoic Xingxingxia Group in the Eastern Tianshan area, NW China, is comprised mainly of siltstone, slate, sandstone and phyllite. New geochemical data for the clastic rocks from the Kawabulake Group were investigated to constrain the provenance and weathering history of the source rocks, in order to evaluate the tectonic evolution of the Eastern Tianshan area. Kawabulake Group rocks are compositionally similar to PAAS (average Post-Archean Australian Shale), indicating derivation from a felsic source that is characterized by depletion in some HFSEs such as Nb, Ta and Ti. The Chemical Index of Alteration (CIA) for the sandstone, siltstone and slate samples (CIA = 60 on average) suggests intensely weathered sources. Light REE-enrichment patterns ((La/Yb)CN = 4-20) coupled with negative Eu anomalies (Eu/Eu* between 0.44 and 0.89 with an average of 0.62) are similar to those of PAAS, consistent with cratonic sources. The major and trace element compositions imply a dominantly Precambrian felsic source region with a minor contribution from mafic materials. The Sr-Nd isotopic compositions and the ages of T DM2 ( 3.4, 2.5-1.8, 1.2 and 1.0 Ga) are consistent with the evolutionary history of Kuluketage in the northern Tarim, suggesting that the Tarim Craton was the main source area for the Kawabulake Group.

  12. Triggers on sulfide saturation in Fe-Ti oxide-bearing, mafic-ultramafic layered intrusions in the Tarim large igneous province, NW China

    Science.gov (United States)

    Cao, Jun; Wang, Christina Yan; Xu, Yi-Gang; Xing, Chang-Ming; Ren, Ming-Hao

    2016-08-01

    Three Fe-Ti oxide-bearing layered intrusions (Mazaertag, Wajilitag, and Piqiang) in the Tarim large igneous province (NW China) have been investigated for understanding the relationship of sulfide saturation, Platinum-group element (PGE) enrichment, and Fe-Ti oxide accumulation in layered intrusions. These mafic-ultramafic layered intrusions have low PGE concentrations (convecting mantle, without appreciable input of lithospheric mantle. The Mazaertag and Wajilitag intrusions have near-chondritic γOs(t) values (+13 to +60) against restricted ɛ Nd(t) values (-0.4 to +2.8), indicating insignificant crustal contamination. Rocks of the Piqiang intrusion have relatively low ɛ Nd(t) values of -3.1 to +1.0, consistent with ˜15 to 25 % assimilation of the upper crust. The rocks of the Mazaertag and Wajilitag intrusions have positive correlation of PGE and S, pointing to the control of PGE by sulfide. Poor correlation of PGE and S for the Piqiang intrusion is attributed to the involvement of multiple sulfide-stage liquids with different PGE compositions or sulfide-oxide reequilibration on cooling. These three layered intrusions have little potential of reef-type PGE mineralization. Four criteria are summarized in this study to help discriminate between PGE-mineralized and PGE-unmineralized mafic-ultramafic intrusions.

  13. Discovery of ultrahigh-T spinel-garnet granulite with pure CO2 fluid inclusions from the Altay orogenic belt, NW China

    Institute of Scientific and Technical Information of China (English)

    LI Zi-long (厉子龙); CHEN Han-lin (陈汉林); SANTOSH M.; YANG Shu-feng (杨树锋)

    2004-01-01

    We first report discovery of the spinel-garnet-orthopyroxene granulite with pure CO2 fluid inclusions from the Fuyun region of the late Paleozoic Altay orogenic belt in Central Asia, NW China. The rock is characterized by an assemblage of garnet, orthopyroxene, spinel, cordierite, biotite, plagioclase and quartz. Symplectites of orthopyroxene and spinel,and orthopyroxene and cordierite indicate decompression under UHT conditions. Mineral chemistry shows that the orthopyroxenes have high XMg and Al2O3 contents (up to 9.23 wt%). Biotites are enriched in TiO2 and XMg and are stable under granulite facies conditions. The garnet and quartz from the rock carry monophase fluid inclusions which show peak melting temperatures of around -56.7 ℃, indicating a pure CO2 species being presented during the ultrahigh-T metamorphism in the Altay orogenic belt. The inclusions homogenize into a liquid phase at temperatures around 15.3-23.8℃ translating into CO2densities of the order of 0.86-0.88 g/cm3. Based on preliminary mineral paragenesis, reaction textures and petrogenetic grid considerations, we infer that the rock was subjected to UHT conditions. The CO2-rich fluids were trapped during exhumation along a clockwise P-T path following isothermal decompression under UHT conditions.

  14. Discovery of ultrahigh-T spinel-garnet granulite with pure CO2 fluid inclusions from the Altay orogenic belt, NW China.

    Science.gov (United States)

    Li, Zi-long; Chen, Han-lin; Santosh, M; Yang, Shu-feng

    2004-10-01

    We first report discovery of the spinel-garnet-orthopyroxene granulite with pure CO2 fluid inclusions from the Fuyun region of the late Paleozoic Altay orogenic belt in Central Asia, NW China. The rock is characterized by an assemblage of garnet, orthopyroxene, spinel, cordierite, biotite, plagioclase and quartz. Symplectites of orthopyroxene and spinel, and orthopyroxene and cordierite indicate decompression under UHT conditions. Mineral chemistry shows that the orthopyroxenes have high XMg and Al2O3 contents (up to 9.23 wt%). Biotites are enriched in TiO2 and XMg and are stable under granulite facies conditions. The garnet and quartz from the rock carry monophase fluid inclusions which show peak melting temperatures of around -56.7 degrees C, indicating a pure CO2 species being presented during the ultrahigh-T metamorphism in the Altay orogenic belt. The inclusions homogenize into a liquid phase at temperatures around 15.3-23.8 degrees C translating into CO2 densities of the order of 0.86-0.88 g/cm3. Based on preliminary mineral paragenesis, reaction textures and petrogenetic grid considerations, we infer that the rock was subjected to UHT conditions. The CO2-rich fluids were trapped during exhumation along a clockwise P-T path following isothermal decompression under UHT conditions.

  15. Discovery of ultrahigh-T spinel-garnet granulite with pure CO2fluid inclusions from the Altay orogenic belt, NW China*

    Science.gov (United States)

    Li, Zi-long; Chen, Han-lin; Santosh, M; Yang, Shu-feng

    2004-01-01

    We first report discovery of the spinel-garnet-orthopyroxene granulite with pure CO2 fluid inclusions from the Fuyun region of the late Paleozoic Altay orogenic belt in Central Asia, NW China. The rock is characterized by an assemblage of garnet, orthopyroxene, spinel, cordierite, biotite, plagioclase and quartz. Symplectites of orthopyroxene and spinel, and orthopyroxene and cordierite indicate decompression under UHT conditions. Mineral chemistry shows that the orthopyroxenes have high XMg and Al2O3 contents (up to 9.23 wt%). Biotites are enriched in TiO2 and XMg and are stable under granulite facies conditions. The garnet and quartz from the rock carry monophase fluid inclusions which show peak melting temperatures of around −56.7 °C, indicating a pure CO2 species being presented during the ultrahigh-T metamorphism in the Altay orogenic belt. The inclusions homogenize into a liquid phase at temperatures around 15.3–23.8 °C translating into CO2 densities of the order of 0.86–0.88 g/cm3. Based on preliminary mineral paragenesis, reaction textures and petrogenetic grid considerations, we infer that the rock was subjected to UHT conditions. The CO2-rich fluids were trapped during exhumation along a clockwise P-T path following isothermal decompression under UHT conditions. PMID:15362187

  16. Science Letters: Discovery of ultrahigh-T spinel-garnet granulite with pure CO2 fluid inclusions from the Altay orogenic belt, NW China

    Institute of Scientific and Technical Information of China (English)

    厉子龙; 陈汉林; SANTOSHM.; 杨树锋

    2004-01-01

    We first report discovery of the spinel-garnet-orthopyroxene granulite with pure CO2 fluid inclusions from the Fuyun region of the late Paleozoic Altay orogenic belt in Central Asia, NW China. The rock is characterized by an assemblage of garnet, orthopyroxene, spinel, cordierite, biotite, plagioclase and quartz. Symplectites of orthopyroxene and spinel, and orthopyroxene and cordierite indicate decompression under UHT conditions. Mineral chemistry shows that the orthopyroxenes have high XMg and Al2O3 contents (up to 9.23 wt%). Biotites are enriched in TiO2 and XMg and are stable under granulite facies conditions. The garnet and quartz from the rock carry monophase fluid inclusions which show peak melting temperatures of around -56.7℃, indicating a pure CO2 species being presented during the ultrahigh-T metamorphism in the Altay orogenic belt. The inclusions homogenize into a liquid phase at temperatures around 15.3-23.8℃ translating into CO2 densities of the order of 0.86-0.88g/cm3. Based on preliminary mineral paragenesis, reaction textures and petrogenetic grid considerations, we infer that the rock was subjected to UHT conditions. The CO2-rich fluids were trapped during exhumation along a clockwise P-T path following isothermal decompression under UHT conditions.

  17. 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.

  18. Structural Geology of Daba Shan and its Tectonic Relationships with the Sichuan Basin and Central China Orogen, China

    Science.gov (United States)

    Guo, X.; Kusky, T.; Li, Z.

    2008-12-01

    Daba Shan is a fold-and-thrust belt located on the northeastern margin of the Sichuan Basin, central China orogen. It is the transitional zone between the Sichuan Basin and Qinling orogenic belt, and it is located in the middle part of the Mianlu suture zone which is the boundary between the Qinling orogenic belt and Yangtze block. Numerous faults and fault-related folds are well preserved in Daba Shan. It is a natural laboratory to carry out fold-thrust belt research on relationships between the Qingling orogen and subsidence in the Sichuan basin. In this talk, I will introduce the general geologic background about and around Daba Shan, including the geologic history of the central China orogen, the formation and development of the Mianlue suture, and the most popular ideas about the geodynamic evolution of Daba Shan, as well as its geologic position between the Sichuan Basin and North China craton and its relative geodynamic relationship with Mianlue suture zone. Field investigations have shown the different fault-related structure styles, e.g. fault-bend fold, fault-propagation fold, duplex structure across the orogen. In addition, a major extensional detachment fault, the Chengkou fault, crops out in the center of the orogen and dips beneath northern Daba Shan fold-thrust belt and Mianlue suture. It is so impressive of the typical and complex geological structure scenarios there, which were mostly caused by the collisional and post-collisional activities between Qinling micro-continent and Yangtze block since mid-Triassic time. Daba Shan has very important tectonic and economic significance in China. Although geoscientists have been working on the Sichuan Basin and central China orogen for many years, Daba Shan has gained little attention. These years, with gas and oil exploration development in foreland basin and fold-thrust belt areas, especially after the discovery of carbonate strata in Daba Shan, its economic potential has become more prominent. This

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. 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

  2. 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.

  3. Paleozoic structural and geodynamic evolution of eastern Tianshan (NW China): welding of the Tarim and Junggar plates

    Institute of Scientific and Technical Information of China (English)

    Jacques Charvet; Liangshu Shu; Sébastien Laurent-Charvet

    2007-01-01

    @@ Chinese East Tianshan is a key area for understanding the Paleozoic accretion of the southern Central Asian Orogenic Belt. A first accretion-collision stage, before the Visean, developed the Eo-Tianshan range, which exhibits north-verging structures. The geodynamic evolution included: i) Ordovician-Early Devonian southward subduction of a Central Tianshan oceanbeneath a Central Tianshan arc; ii) Devonian oceanic closure and collision between Central Tianshan arc and Yili-North Tianshan block, along the Central Tianshan Suture Zone; iii) Late Devonian-earliest Carboniferous closure of a South Tianshan back-arc basin, and subsequent Central Tianshan-Tarim active margin collision along the South Tianshan Suture Zone. A second stage involved: i) Late Devonian-Carboniferous southward subduction of North Tianshan ocean beneath the Eo-Tianshan active margin (Yili-North Tianshan arc);ii) Late Carboniferous-Early Permian North TianshanJunggar collision.

  4. 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.

  5. 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.

  6. The Canada Basin compared to the southwest South China Sea: Two marginal ocean basins with hyper-extended continent-ocean transitions

    Science.gov (United States)

    Li, Lu; Stephenson, Randell; Clift, Peter D.

    2016-11-01

    Both the Canada Basin (a sub-basin within the Amerasia Basin) and southwest (SW) South China Sea preserve oceanic spreading centres and adjacent passive continental margins characterized by broad COT zones with hyper-extended continental crust. We have investigated strain accommodation in the regions immediately adjacent to the oceanic spreading centres in these two basins using 2-D backstripping subsidence reconstructions, coupled with forward modelling constrained by estimates of upper crustal extensional faulting. Modelling is better constrained in the SW South China Sea but our results for the Canada Basin are analogous. Depth-dependent extension is required to explain the great depth of both basins because only modest upper crustal faulting is observed. A weak lower crust in the presence of high heat flow and, accordingly, a lower crust that extends far more the upper crust are suggested for both basins. Extension in the COT may have continued even after seafloor spreading has ceased. The analogous results for the two basins considered are discussed in terms of (1) constraining the timing and distribution of crustal thinning along the respective continental margins, (2) defining the processes leading to hyper-extension of continental crust in the respective tectonic settings and (3) illuminating the processes that control hyper-extension in these basins and more generally.

  7. 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.

  8. Pseudofaults and associated seamounts in the conjugate Arabian and Eastern Somali basins, NW Indian Ocean - New constraints from high-resolution satellite-derived gravity data

    Science.gov (United States)

    Sreejith, K. M.; Chaubey, A. K.; Mishra, Akhil; Kumar, Shravan; Rajawat, A. S.

    2016-12-01

    Marine gravity data derived from satellite altimeters are effective tools in mapping fine-scale tectonic features of the ocean basins such as pseudofaults, fracture zones and seamounts, particularly when the ocean basins are carpeted with thick sediments. We use high-resolution satellite-generated gravity and seismic reflection data to map boundaries of pseudofaults and transferred crust related to the Paleocene spreading ridge propagation in the Arabian and its conjugate Eastern Somali basins. The study has provided refinement in the position of previously reported pseudofaults and their spatial extensions in the conjugate basins. It is observed that the transferred crustal block bounded by inner pseudofault and failed spreading ridge is characterized by a gravity low and rugged basement. The refined satellite gravity image of the Arabian Basin also revealed three seamounts in close proximity to the pseudofaults, which were not reported earlier. In the Eastern Somali Basin, seamounts are aligned along NE-SW direction forming ∼300 km long seamount chain. Admittance analysis and Flexural model studies indicated that the seamount chain is isostatically compensated locally with Effective Elastic Thickness (Te) of 3-4 km. Based on the present results and published plate tectonic models, we interpret that the seamounts in the Arabian Basin are formed by spreading ridge propagation and are associated with pseudofaults, whereas the seamount chain in the Eastern Somali Basin might have probably originated due to melting and upwelling of upper mantle heterogeneities in advance of migrating/propagating paleo Carlsberg Ridge.

  9. Tectonic Features and Its Control Over Oil and Gas in Beibuwan Basin

    Institute of Scientific and Technical Information of China (English)

    Lin Dianzhong

    1995-01-01

    @@ Main part of Beibuwan Basin located in Beibuwan Bay, South China Sea, is a Cenozoic basin with mainly of Tertiary sedimentation. It is dissected into tectonic framework of interchange of multi-sag and multiuplift units by two groups of big riff with NE and NW trend. The fault sags resulted from the fault dissection are Weixinan, Wushi, Maichen, Fushan (on Hainan Island )etc. (Fig. 1).

  10. A new type of rare earth elements deposit in weathering crust of Permian basalt in western Guizhou, NW China

    Institute of Scientific and Technical Information of China (English)

    YANG Ruidong; WANG Wei; ZHANG Xiaodong; LIU Ling; WEI Huairui; BAO Miao; WANG Jingxin

    2008-01-01

    A new type of rare earth elements (REEs) deposit was discovered from the gaolinite mudstone in the weathering crust of Permian basalt, Bijie region, western Guizhou, China. It contained ∑-RE2O3 0.065%-1.086%. This type of REEs deposit was widely distributed with steady horizon and thickness of 3-4 m. The ore-bearing weathering crust (kaolinite) of the three discovered REEs deposits belonged to the third episode of the Emeishan basalt eruption. The new type of REEs deposit was suggested that basalt (tuff) weathering could lead to the en- richment of the rare earth elements. Therefore, it is of important economic significance to explore REEs deposits in the weathering crust of basalt (tufts) in Yunnan, Guizhou, and Sichuan Provinces.

  11. Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor,NW China Since the Last Interglacial

    Institute of Scientific and Technical Information of China (English)

    YANG Taibao; YU Yongtao; LI Jijun; AN Congrong; LIU Jinfeng; ZHANG Junyan

    2004-01-01

    Paleomagnetic determinations on lithological profiles of two paralleled long drilling cores covering the past 130 kyr B.P., GT40 and GT60,from the Yanchi Playa in the arid Northwestern China,indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports,4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified asexcursion events coeval with the Mono Lake Event (28.4 kyr~25.8 kyr), Laschamp Event (43.3 kyr~40.5kyr), Gaotai Event (8a.8 kyr~72.4 kyr) and the Blake Event (127.4 kyr~113.3 kyr), respectively. GT-9correlates with the above-mentioned Gaotai Event,GT-7 and GT-6 correspond to two stages of theLaschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima,anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events(H1-H6). Here, we tentatively propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness.During the transitional stages when the earth's magnetic field shifted between a temporal normal and a negative period, the earth's magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earth's incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions.

  12. 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.

  13. Terrestrial heat flow in Junggar Basin,Northwest China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on temperature logs of 117 boreholes and thermal conductivity of 119 rock samples,the first group of 35 heat flow data in the Junggar Basin are presented.The thermal gradients vary between 11.6 and 26.5℃/km ,and the thermal conductivity changes from 0.17 to 3.6 W/mK.Heat flow ranges from 23.4 to 53.7 mW/m2 with a mean of (42.3± 7.7) mW/m2.The heat flow pattern shows that heat flow is higher in the uplifts and lower in the depressions.The factors affecting the heat flow and its distribution include basin type,basement structure,sediment thickness,radioactive heat generation,etc.The overall low present-day heat flow in the Junggar Basin reflected its tectonothermal evolution characterized by lithospheric thickening,thrust and fault at shallow crust as well as consequently quick subsidence during the Late Cenozoic.

  14. Crustal structure and magnetic lineation along two geo-traverses from western continental margin of India to Eastern Somali Basin, NW Indian Ocean

    Science.gov (United States)

    Chaubey, A. K.; Anshu, A.; Sreejith, K.; Pandey, A.

    2012-12-01

    Shipborne gravity and magnetic data along two parallel geo-traverses spanning from western continental margin of India to off Seychelles are used to delineate crustal structure and magnetic pattern of major structural features - western continental margin of India, Laxmi Basin, Laxmi Ridge, Arabian Basin, slow spreading Carlsberg Ridge and Eastern Somali Basin. The seismically constrained gravity models along the geo-traverses suggest considerable variation in crustal thickness - about 38 km on continental shelf of western India to about 4 km of the Eastern Somali Basin. The Eastern Somali Basin is characterized by thin oceanic crustal thickness (~3 to 4 km) as compared to its conjugate Arabian Basin where thickness varies from 5 to 6 km. The magnetic anomalies along the geo-traverse reveal three distinct zones: (i) a zone of relative high frequency short wavelength younger anomalies over the axial parts of the Carlsberg Ridge, (ii) a zone of well developed Early Tertiary magnetic anomalies in both the Arabian and Eastern Somali basins, and (iii) relative magnetic quiet zone, between the above two zones, representing a hiatus in spreading. Based on the results, we present a comparative analysis of crustal configuration and magnetic pattern of major structural features of the study area and discuss its tectonic evolution.

  15. Mode of opening of an oceanic pull-apart: The 20°N Basin along the Owen Fracture Zone (NW Indian Ocean)

    Science.gov (United States)

    Rodriguez, Mathieu; Chamot-Rooke, Nicolas; Fournier, Marc; Huchon, Philippe; Delescluse, Matthias

    2013-09-01

    basins are common features observed at releasing bends along major strike-slip faults. The formation and structural evolution of such basins have mostly been investigated in the continental domain and by sandbox laboratory experiments or numerical models. Here we present recently acquired multibeam bathymetry, 3.5 kHz echo sounder, and seismic profiles across the 20°N pull-apart Basin along the India-Arabia transform boundary, known as the Owen Fracture Zone (OFZ). Using nearby oceanic drilling (Deep Sea Drilling Project 222), we constrain the structural evolution of the basin since opening some 3 Myr ago. The 20°N Basin is large (90 km long and 35 km wide) despite limited transcurrent motion (~10 km). The first stage involved the formation of a step over along the OFZ and the subsequent isolation of a subsiding half graben. Extension and subsidence were further partitioned over three distinct subbasins separated by complex sets of transverse faults. The size of the basin was enhanced by gravity-driven collapse. The 20°N Basin has been a catchment for Indus turbidites since its opening, which provide a good record of syn-sedimentary deformation. The deformation related to the subsidence of the half graben mimics rollover structures commonly encountered in salt tectonics, suggesting that subsidence was accommodated by one or several décollement layers at depth. Despite a different rheological context, the subsurface structure of the nascent oceanic 20°N Basin is very similar to the more mature continental Dead Sea Basin along the Levant Fault, which also displays subbasins separated by transverse faults.

  16. 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.

  17. Geochemistry and Re-Os geochronology of the organic-rich sedimentary rocks in the Jingtieshan Fe-Cu deposit, North Qilian Mountains, NW China

    Science.gov (United States)

    Yang, Xiuqing; Zhang, Zuoheng; Li, Chao; Duan, Shigang; Jiang, Zongsheng

    2016-04-01

    The Jingtieshan Group in the North Qilian Mountains, NW China, is dominantly composed of banded iron formations (BIFs), copper deposits and organic-rich sedimentary rocks (ORS, carbonaceous phyllite). X-ray diffraction analysis of the ORS shows the mineral assemblage to be quartz + clay minerals. The total organic carbon contents show a range of 0.44-1.72%. Here we present the results of the geochemistry and Re-Os geochronology of the ORS from the Jingtieshan Group. The high values of Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alteration (PIA), and Th/U ratio, indicate intense weathering. The Al2O3/TiO2, Zr/Sc, Th/Sc, La/Th ratios, high rare earth elements abundances, light rare earth elements enrichment (normalized to chondrite), and distinctly negative Eu anomalies, suggest that the Jingtieshan Group ORS were derived mainly from felsic volcanic units. The new Re-Os isochron age of 1308 ± 100 Ma (2σ, n = 6, MSWD = 23) broadly overlap with the previous published ages determined using Sm-Nd and U-Pb isotope systems. The new age represents the depositional age of the Jingtieshan Group, as well that of BIF in the Jingtieshan area. Furthermore, the initial 187Os/188Os ratios (0.44 ± 0.07) indicate that the Os in the seawater was dominantly derived from hydrothermal fluids (∼75%). The Ce anomaly (Ce/Ce∗ = 0.95-1.00) and V/(V + Ni) ratios (0.71-0.86), as well as the lack of enrichment in redox-sensitive trace elements such as U, V, Zn, Pb, Cu, Ni, Cr, Co and Mn, together with the presence of overlying BIF, suggest that the Jingtieshan area represents a ferruginous deep-water succession. This, and intense submarine hydrothermal activities contributed to the deposition of the Jingtieshan BIF.

  18. Microstructures and petro-fabrics of lawsonite blueschist in the North Qilian suture zone, NW China: Implications for seismic anisotropy of subducting oceanic crust

    Science.gov (United States)

    Cao, Yi; Jung, Haemyeong; Song, Shuguang

    2014-07-01

    We conducted a detailed study on the microstructures and petro-fabrics of massive and foliated lawsonite blueschist (LBS) in North Qilian suture zone, NW China. The lattice preferred orientation (LPO) of glaucophane and lawsonite in foliated lawsonite blueschist (LBS) is considered to be dominantly formed by the deformation mechanism of dislocation creep and rigid-body rotation, respectively. The LPO of glaucophane is mainly characterized by the [001] axis aligning parallel to lineation and the [100] axis and (110) pole plunging perpendicular to foliation. In contrast, the LPO of lawsonite features the maximum [010] axis concentrated close to lineation and the [001] axis strongly clustered normal to foliation. The preferred orientation of [010] axis of lawsonite parallel to lineation is supported by a two-dimensional numerical modeling using the finite-volume method (FVM). The mineral LPOs are much stronger in foliated LBS than in massive LBS. In addition, a kinematic vorticity analysis suggests that both pure shear dominant (Wm = 0.18-0.26) and simple shear dominant (Wm = 0.86-0.93) deformation regimes are present in foliated LBS. The [001] axis and (010) pole of glaucophane, and the [100] and [010] axes of lawsonite, tend to distribute in a foliation-parallel girdle in the pure shear dominant samples, but simple shear dominant samples display more lineation-parallel concentrations of a [001] axis of glaucophane and a [010] axis of lawsonite. Because the whole-rock seismic anisotropies in foliated LBS are significantly higher than those in massive LBS and a counteracting effect on seismic anisotropies occurs between glaucophane and lawsonite, the delay time of fast S-wave polarization anisotropy induced by an actual subducting oceanic crust with a high subducting angle (> 45-60°) is expected to range from 0.03 to 0.09 s (lower bound for massive LBS) and from 0.1 to 0.3 s (upper bound for foliated epidote blueschist).

  19. Vegetation patterns and nature reserve construction in an extremely-arid desert in Anxi, NW China's Gansu Province.

    Science.gov (United States)

    Liu, Hong-Yan; Xu, Li-Hong; Chen, Chang-Du; Cui, Hai-Ting; Xu, Xing-Ying

    2002-07-01

    Anxi County is located in the northwestern part of the Hexi Corridor in Gansu Province and has the sole national level nature reserve of extremely-arid desert in China. Phytosociological methods (Braun-Blanquet, 1964) are used to classify plant community types in this area. Eleven are distinguished, including six of deserts, four of cases and one transitional type between deserts and cases. Direct gradient analysis (DCA) is employed to correlate the distribution of plant communities to physiogeographic conditions. This study makes clear that water is the most important ecological factor for the distribution of plant species and communities in this area. The effects of water have been demonstrated in different ways. A vegetation gradient from lower altitude to higher altitude in the southern part of the reserve is driven by a precipitation gradient. The effects of the depth of ground water table contribute to the differentiation of vegetation from desert to oasis in the flat area. In a finer scale, the washed gullies have obviously higher species richness and also higher vegetation cover than the surround gobi surfaces, possibly caused by the effects of floods. The vegetation patterns demonstrate that the area of Anxi County is a complete landscape unit. The range of the current nature reserve is not large enough for the purpose of conserving the unique biodiversity in this area.

  20. Vegetation patterns and nature reserve construction in an extremely-arid desert in Anxi,NW China's Gansu Province

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Anxi County is located in the northwestern part of the Hexi Corridor in Gansu Province and has the sole national level nature reserve of extremely-arid desert in China.Phytosociological methods (Braun-Blanquet,1964) are used to classify plant community types in this area.Eleven are distinguished,including six of deserts,four of oases and one transitional type between deserts and oases.Direct gradient analysis ( DCA ) is employed to correlate the distribution of plant communities to physiogeographic conditions.This study makes clear that water is the most important ecological factor for the distribution of plant species and communities in this area.The effects of water have been demonstrated in different ways.A vegetation gradient from lower altitude to higher altitude in the southern part of the reserve is driven by a precipitation gradient.The effects of the depth of ground water table contribute to the differentiation of vegetation from desert to oasis in the flat area.In a finer scale,the washed gullies have obviously higher species richness and also higher vegetation cover than the surround gobi surfaces,possibly caused by the effects of floods.The vegetation patterns demonstrate that the area of Anxi County is a complete landscape unit.The range of the current nature reserve is not large enough for the purpose of conserving the unique biodiversity in this area.

  1. Molecular fossil and paleovegetation records of paleosol S4 and adjacent loess layers in the Luochuan loess section, NW China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using gas chromatography-mass spectrometry (GC-MS) technique, a series of biomarkers were identi- fied, including n-alkanes, n-alkane-2-ones, isoprenoid etc. from the loess-paleosol samples collected from the S4 and adjacent L5, L4 of the Luochuan loess section, Northwestern China. Based on these data, especially n-alkanes and high-resolution magnetic susceptibility and grain size data, the pa- leoenvironment and paleovegetation history during S4 was reconstructed. The CPI (Carbon Predomi- nance Index) and correlation between n-alkanes and magnetic susceptibility and grain size data dem- onstrated that the molecular fossils in paleosol and loess layers can reflect the vegetation condition during the loess-paleosol formation, if the allochthonous organic inputs could be excluded reasonably. The ACL (average chain length) index is correlated well with paleomagnetic susceptibility and grain size variations, displaying their good synchrony with warm and humid climate. However, it relatively lagged behind the paleomagnetic susceptibility and the grain size variations when the climate began to deteriorate. During the formation period of paleosol, the n-alkanes was dominated by C31 homologue, indicating that the primary organic input originated from herbs. Our study also demonstrated that the herbs were more flourish than wood plants in Loess Plateau, especially in the Luochuan area during the warm and humid phase, and there was no typical forest vegetation developed in the studied period.

  2. Exploration Potential of Atectonic Oil-gas Pools in the Northern Shelf Basin of the South China Sea

    Institute of Scientific and Technical Information of China (English)

    ZhuWeilin; WangZhenfeng; LvMing

    2004-01-01

    Large-scale oil exploration has been done and large quantities of oil-gas fields have been found in the northern shelf basin of the South China Sea for more than 20 years. The tectonic oil-gas pools are the main type. With the exploration to be deepened, looking for atectonic oil-gas pools is listed in China's exploration strategy. There are advantages for the forming of atectonic oil-gas pools in the northern shelf basin of the South China Sea. Because the level of water has been frequently changing within all historical periods, lithozones are changed alternately in both vertical and lateral directions and formed lithologic deposition especially at low water level stages, such as the low-lying fans of basin-floor fans and slope fans. Due to frequent tectonic movement within all historical periods, many structural surfaces and structural unconformities were formed. At the same time, they also formed many kinds of structural unconformity oil-gas pools. According to our exploration and research, the promising areas of atectonic reservoirs within marine basins include: (1) the basin-floor fan of the deep water district, such as the central depression of the Southeast Qiong basin and Baiyun sag in the Zhujiangkou basin; (2) the frontal area of the large ancient delta, such as the Lingao structural belt in the Yingge Sea basin and Huizhou sag in the Zhujiangkou basin; (3) the unconformity pinchout belt or denudation belt in the slope area and the uplift area, for instance, the Yingdong slope belt in the Yingge Sea basin and Yacheng 13-1 structural belt in the southeast Qiong basin. All this proves that the prospects for atectonic oil-gas pools in the northern shelf basin of the South China Sea are very broad.

  3. 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

  4. Geochemical characteristics of oils from the Chaidamu, Shanganning and Jianghan Basins, China

    Science.gov (United States)

    Philp, R. P.; Fan, P.; Lewis, C. A.; Zhu, H.; Wang, H.

    Thirty oil samples from the Shanganning, Jianghan and Chaidamu Basins in China have been examined by a number of geochemical techniques. The techniques included gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and tandem mass spectrometry using a triple stage quadrupole mass spectrometer (MS/MS), stable isotope mass spectrometry. There were several reasons for undertaking this study. Firstly was the attempted oil-source rock correlation studies within the individual basins. Secondly was the continuing quest for novel, or sets of, biomarkers that could be assigned to saline and hypersaline environments and subsequently used to characterize other similar depositional environments. Thirdly was the desire to compare and contrast results obtained from these three basins with those from a similar study being undertaken on the South Florida Basin and the Anadarko Basin in the U.S.A. Whereas the Chinese basins are lacustrine, those in the U.S.A. are marine. For the purposes of this paper, only the results from the three Chinese basins will be discussed. In addition to examining the results from the biomarker distributions as determined by GC-MS and GC-MS/MS, the results are correlated with those obtained from the δ 13C isotropic determinations. For example, three oils in the Shanganning Basin showed anomalous isotopic data, which immediately suggested that they should be examined in greater detail than the remaining oils, all of which correlated quite closely with each other. A combination of results used in this way is far more valuable than the biomarker data alone. In summary, the results demonstrate that various families of oils in the three basins can be distinguished on the basis of geochemical data and in many cases on the basis of the carbon isotopic composition alone. The oils from the Shanganning Basin had the lightest values, around -32%, whereas the Chaidamu were the heaviest in the -26% region. The Jianghan oils had values intermediate to

  5. 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.

  6. Regime Shift Identification of Runoff and Sediment Loads in the Yellow River Basin, China

    OpenAIRE

    Fei Wang; Guangju Zhao; Xingmin Mu; Peng Gao; Wenyi Sun

    2014-01-01

    Runoff and sediment loads have exhibited significant changes over the past six decades in the Yellow River Basin, China. The current study evaluates the changing trends and regime shifts in runoff and sediment loads at both the annual and monthly time scales. The associated spatial and temporal variations are analyzed by a sequential t-test analysis of the regime shifts (STARS) approach and the “breaks for additive seasonal and trend” (BFAST) model using hydrological data at eight stations f...

  7. 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 ...

  8. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China:Evidence from apatite fission track analysis

    Institute of Scientific and Technical Information of China (English)

    Wenhao Tang; Zhicheng Zhang; Jianfeng Li; Ke Li; Zhiwen Luo; Yan Chen

    2015-01-01

    Apatite fission track (AFT) analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0e13.2 mm) mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassiceearly Cretaceous and the OligoceneeMiocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma), recording the earlier rapid uplift phase during the late JurassiceCretaceous, while the ages in the north pied-mont of the Bogda Mountain (namely the northeast part) are younger (<60 Ma), mainly reflecting the later rapid uplift phase in the OligoceneeMiocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  9. Status, source and health risk assessment of polycyclic aromatic hydrocarbons in street dust of an industrial city, NW China.

    Science.gov (United States)

    Jiang, Yufeng; Hu, Xuefei; Yves, Uwamungu J; Zhan, Huiying; Wu, Yingqin

    2014-08-01

    The status, source and health risk of street-dust-borne polycyclic aromatic hydrocarbons (PAHs) in Lanzhou of Northwest China were investigated. The total level of the 21 PAHs ranged from 1470 to 13,700 µg kg(-1) and that of the 16 priority PAHs from 1240 to 10,700 µg kg(-1). Higher levels of PAHs were mainly distributed in the Chengguan and Qilihe districts at Lanzhou central areas, and the lower levels were in Anning and Xigu districts. The level of seven potential carcinogenic PAHs generally accounted for 35-40 percent of total PAHs, and the PAHs contained two to four rings, mainly phenanthrene, benzo[b]fluoranthene and fluoranthene. The total level of PAHs increased with the decreasing particle size in the street dust. The correlation analysis suggested that the total organic carbon (TOC) was only slightly affected the PAH accumulation in street dust. The isomer ratios and principal component analysis indicated that the dust-borne PAHs in the dust were derived primarily from the combustion of biomass, coal and petroleum emission. The toxic equivalent concentrations (BaP(eq)) of dust-borne PAHs ranged from 115 to 827 µg BaP(eq) kg(-1), with a mean of 300 µg BaP(eq) kg(-1). The 95 percent upper confidence limit of Incremental Lifetime Cancer Risk due to human exposure to urban surface dust-borne PAHs in Lanzhou urban area was 2.031 × 10(-6) for children and 1.935 × 10(-6) for adults.

  10. Role of vegetation and landcover dynamics on the recycling of water in two endorheic watersheds of NW China (Gansu Province)

    Science.gov (United States)

    Matin, M. A.; Bourque, C. P.-A.

    2015-01-01

    In this study, we analysed the role of vegetation in the recycling of water in two endorheic watersheds in northwest China, namely within the Shiyang and Hei River watersheds (Gansu Province), along a gradient of elevation zones and within-zone landcover types. Each watershed was subdivided into four elevation zones representative of (i) oasis plains and foothills, and (ii) low-, (iii) mid-, and (iv) high-mountain elevations. By means of monthly summaries of enhanced vegetation index (EVI), DEM-height values, terrain orientation, and a decision-tree classifier, landcover in the study area (consisting of oases, deserts, and adjoining Qilian Mountains) was classified into 11 unique landcover types. Comparison of monthly vegetation phenology with precipitation and snowmelt dynamics within the same watersheds over a ten-year period (2000-2009) suggested that the onset of the precipitation season in the mountains (in May) was triggered by the greening of vegetation and increased production of water vapour at the base of the mountains. Seasonal evolution of in-mountain precipitation correlated fairy well with the temporal variation in oasis-vegetation coverage and phenology (of crops and grasses) characterised by monthly EVI, giving r2 values of 0.65 and 0.85 for the Shiyang and Hei River watersheds, respectively. Generally, comparisons between same-zone monthly precipitation volumes and EVI provided weaker correlations. Start of the growing season in the oases was shown to coincide with the discharge of meltwater from the low- to mid-elevations of the Qilian Mountains in mid-to-late March. Comparison of water volumes associated with in-mountain production of rainfall and snowmelt with that associated with actual evapotranspiration revealed that about 90% of the water flowing downslope to the oases was eventually returned to the Qilian Mountains as water vapour generated in the lowlands.

  11. Three-dimensional audio-frequency magnetotelluric imaging of Akebasitao granitic intrusions in Western Junggar, NW China

    Science.gov (United States)

    Yang, Bo; Zhang, Anqi; Zhang, Sheng; Liu, Ying; Zhang, Shengye; Li, Yongtao; Xu, Yixian; Wang, Qinyan

    2016-12-01

    An audio-frequency magnetotelluric (AMT) array was deployed here to map the resistivity structure of the Akebasitao intrusions and the surrounding area in Western Junggar, China. High quality AMT data were acquired at 463 sites that covered the whole Akebasitao intrusions. The latest 3D electromagnetic inversion system, ModEM, was employed to invert the AMT dataset. A high resolution resistivity model was recovered by using a nonlinear conjugate-gradient scheme. The Akebasitao intrusions, the most pronounced resistive features in the preferred model, are clearly imaged from shallow depths to more than 10 km, with some conductive zones and spots in and surrounding it. The shape of the Akebasitao pluton is asymmetrical mushroom-like, suggesting an extension stress environment at its forming age (the Late Carboniferous to the Early Permian) in Western Junggar. Our explanation is consistent with the subducting spreading ridge tectonic model for Western Junggar in the Late Carboniferous, with a paleo-Asia ocean plate subducting northwestward beneath Karamay arc, as former studies proposed. The upwelling channel of the Akebasitao pluton seems to be located at its center. The Darbut Fault has been clearly imaged as a subvertical narrow conductive zone extending from the surface to 3-5 km or deeper. The most prominent conductors are two elongate zones in depths deeper than 500 m. Other conductive zones can also be identified surrounding the boundaries of the Akebasitao pluton, which can be interpreted as pyrometasomatic metamorphism relating to magmatic activities. Because the ophiolitic rocks outcrop as some lens along these two boundaries, and as previous studies showed that the serpentine metamorphosed from peridotite with well-connected magnetite possessing high conductivity, the conductors may therefore also represent their sources in depth.

  12. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China: Evidence from apatite fission track analysis

    Directory of Open Access Journals (Sweden)

    Wenhao Tang

    2015-07-01

    Full Text Available Apatite fission track (AFT analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0–13.2 μm mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassic–early Cretaceous and the Oligocene–Miocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma, recording the earlier rapid uplift phase during the late Jurassic–Cretaceous, while the ages in the north piedmont of the Bogda Mountain (namely the northeast part are younger (<60 Ma, mainly reflecting the later rapid uplift phase in the Oligocene–Miocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  13. Ordovician Basement Hydrocarbon Reservoirs in the Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    YAN Xiangbin; LI Tiejun; ZHANG Tao

    2004-01-01

    Ordovician marine carbonate basement traps are widely developed in the paleo-highs and paleo-slopes in the Tarim Basin. Reservoirs are mainly altered pore-cavity-fissure reservoirs. Oil sources are marine carbonate rocks of the Lower Paleozoic. Thus, the paleo-highs and paleo-slopes have good reservoiring conditions and they are the main areas to explore giant and large-scale oil reservoirs. The main factors for their reservoiring are: (1) Effective combination of fenestral pore-cavity-fracture reservoirs, resulting from multi-stage, multi-cyclic karstification (paleo-hypergene and deep buried) and fracturing, with effective overlying seals, especially mudstone and gypsum mudstone in the Carboniferous Bachu Formation, is essential to hydrocarbon reservoiring and high and stable production; (2) Long-term inherited large rises and multi-stage fracture systems confine the development range of karst reservoirs and control hydrocarbon migration, accumulation and reservoiring; (3) Long-term multi-source hydrocarbon supply, early reservoiring alteration and late charging adjustment are important reservoiring mechanisms and determine the resource structure and oil and gas properties. Favorable areas for exploration of Ordovician carbonate basement hydrocarbon reservoirs in the Tarim Basin are the Akekule rise, Katahe uplift, Hetianhe paleo-high and Yakela faulted rise.

  14. Active shortening and intermontane basin formation in the central Puna Plateau: Salar de Pocitos, NW Argentina (24°37'S, 67°03'W)

    Science.gov (United States)

    Strecker, Manfred; Bookhagen, Bodo; Freymark, Jessica; Pingel, Heiko; Alonso, Ricardo N.

    2015-04-01

    Similar to other Cenozoic orogenic plateaus, extensional tectonics associated with mafic volcanism typifies the Altiplano-Puna of the southern Central Andes, while the flanks of the plateau and adjacent foreland areas experience shortening. Extensional tectonism in the plateau region since the late Miocene has been explained with delamination of lithospheric mantle. However, new evidence for protracted basin-wide shortening in the Salar de Pocitos region in the south-central Puna documents that the kinematic changeover from shortening to extension is highly diachronous. In this study we assess the deformation and geomorphic history of the Salar de Pocitos region using DGPS surveys, CRN dating of deformed pediment surfaces, and U/Pb dating of volcanic ash horizons in deformed strata. With average elevations of about 3.7 km the Altiplano-Puna is a first-order morphotectonic province of the southern central Andes and constitutes the world's second largest orogenic plateau. With few exceptions the Andean plateau consists of internally drained, partly coalesced sedimentary basins that are mainly bordered by reverse-fault bounded ranges, 5 to 6 km high. While there are many unifying plateau characteristics in the Altiplano (north) and Puna (south), including internal drainage, semi-arid to arid climate and associated deposition of evaporites, there are notable differences between both plateau sectors. In contrast to the vast Altiplano basin of Bolivia, the Argentine Puna comprises numerous, smaller and partly coalesced basins that reflect continued comparmentalization by the combined effects of tectonism and volcanic activity. The N-S oriented Salar de Pocitos basin is the vestige of a formerly contiguous sedimentary basin within the Puna interior. Unlike many other basins in this region it is bordered by the limb of an anticline developed in Tertiary sedimentary rocks on the west, while the eastern border is a reverse-faulted range front. To the north and south the

  15. 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.

  16. Quantification of Climate Changes and Human Activities That Impact Runoff in the Taihu Lake Basin, China

    Directory of Open Access Journals (Sweden)

    Dingzhi Peng

    2016-01-01

    Full Text Available Although a fragile climate region, the Taihu Lake Basin is among the most developed regions in China and is subjected to intense anthropogenic interference. In this basin, water resources encounter major challenges (e.g., floods, typhoons, and water pollution. In this study, the impacts of climate changes and human activities on hydrological processes were estimated to aid water resource management in developed regions in China. The Mann-Kendall test and cumulative anomaly curve were applied to detect the turning points in the runoff series. The year of 1982 divides the study period (1956~2008 into a baseline period (1956~1981 and a modified period (1982~2008. The double mass curve method and the hydrological sensitivity method based on the Budyko framework were applied to quantitatively attribute the runoff variation to climate changes and human activities. The results demonstrated that human activities are the dominant driving force of runoff variations in the basin, with a contribution of 83~89%; climate changes contributed to 11~17% of the variations. Moreover, the subregions of the basin indicated that humans severely disturbed the runoff variation, with contributions as high as 95~97%.

  17. 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.

  18. 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.

  19. How many sutures in the southern Central Asian Orogenic Belt:Insights from East XinjiangeWest Gansu (NW China)?

    Institute of Scientific and Technical Information of China (English)

    Wenjiao Xiao; Jun Luo; Chunming Han; Wei Liu; Bo Wan; Ji’en Zhang; Songjian Ao; Zhiyong Zhang; Dongfang Song; Zhonghua Tian

    2014-01-01

    How ophiolitic mélanges can be defined as sutures is controversial with regard to accretionary orogenesis and continental growth. The Chinese Altay, East Junggar, Tianshan, and Beishan belts of the southern Central Asian Orogenic Belt (CAOB) in Northwest China, offer a special natural laboratory to resolve this puzzle. In the Chinese Altay, the Erqis unit consists of ophiolitic mélanges and coherent assemblages, forming a Paleozoic accretionary complex. At least two ophiolitic mélanges (Armantai, and Kelameili) in East Junggar, characterized by imbricated ophiolitic mélanges, Nb-enriched basalts, adakitic rocks and volcanic rocks, belong to a DevonianeCarboniferous intra-oceanic island arc with some Paleozoic ophiolites, superimposed by Permian arc volcanism. In the Tianshan, ophiolitic mélanges like Kanggurtag, North Tianshan, and South Tianshan occur as part of some Paleozoic accretionary complexes related to amalgamation of arc terranes. In the Beishan there are also several ophiolitic mélanges, including the Hongshishan, XingxingxiaeShibangjing, HongliuheeXichangjing, and Liuyuan ophiolitic units. Most ophiolitic mélanges in the study area are characterized by ultramafic, mafic and other components, which are juxtaposed, or even emplaced as lenses and knockers in a matrix of some coherent units. The tectonic settings of various components are different, and some adjacent units in the same mélange show contrasting different tectonic settings. The formation ages of these various com-ponents are in a wide spectrum, varying from Neoproterozoic to Permian. Therefore we cannot assume that these ophiolitic mélanges always form in linear sutures as a result of the closure of specific oceans. Often the ophiolitic components formed either as the substrate of intra-oceanic arcs, or were accreted as lenses or knockers in subduction-accretion complexes. Using published age and paleogeographic con-straints, we propose the presence of (1) a major early Paleozoic

  20. How many sutures in the southern Central Asian Orogenic Belt: Insights from East Xinjiang–West Gansu (NW China?

    Directory of Open Access Journals (Sweden)

    Wenjiao Xiao

    2014-07-01

    Full Text Available How ophiolitic mélanges can be defined as sutures is controversial with regard to accretionary orogenesis and continental growth. The Chinese Altay, East Junggar, Tianshan, and Beishan belts of the southern Central Asian Orogenic Belt (CAOB in Northwest China, offer a special natural laboratory to resolve this puzzle. In the Chinese Altay, the Erqis unit consists of ophiolitic mélanges and coherent assemblages, forming a Paleozoic accretionary complex. At least two ophiolitic mélanges (Armantai, and Kelameili in East Junggar, characterized by imbricated ophiolitic mélanges, Nb-enriched basalts, adakitic rocks and volcanic rocks, belong to a Devonian–Carboniferous intra-oceanic island arc with some Paleozoic ophiolites, superimposed by Permian arc volcanism. In the Tianshan, ophiolitic mélanges like Kanggurtag, North Tianshan, and South Tianshan occur as part of some Paleozoic accretionary complexes related to amalgamation of arc terranes. In the Beishan there are also several ophiolitic mélanges, including the Hongshishan, Xingxingxia–Shibangjing, Hongliuhe–Xichangjing, and Liuyuan ophiolitic units. Most ophiolitic mélanges in the study area are characterized by ultramafic, mafic and other components, which are juxtaposed, or even emplaced as lenses and knockers in a matrix of some coherent units. The tectonic settings of various components are different, and some adjacent units in the same mélange show contrasting different tectonic settings. The formation ages of these various components are in a wide spectrum, varying from Neoproterozoic to Permian. Therefore we cannot assume that these ophiolitic mélanges always form in linear sutures as a result of the closure of specific oceans. Often the ophiolitic components formed either as the substrate of intra-oceanic arcs, or were accreted as lenses or knockers in subduction-accretion complexes. Using published age and paleogeographic constraints, we propose the presence of (1 a major

  1. Titanite-scale insights into multi-stage magma mixing in Early Cretaceous of NW Jiaodong terrane, North China Craton

    Science.gov (United States)

    Jiang, Peng; Yang, Kui-Feng; Fan, Hong-Rui; Liu, Xuan; Cai, Ya-Chun; Yang, Yue-Heng

    2016-08-01

    The Early Cretaceous Guojialing-type granodiorites in northwestern Jiaodong terrane carry significant records for strong mantle-crust interaction during the destruction of North China Craton (NCC); however, the definite petrogenetic mechanism and detailed magmatic process remain an enigma. Titanite in igneous rocks can serve as an effective petrogenetic indicator. Here, we present integrated geochronological and geochemical studies on titanites from Guojialing-type granodiorites and their dioritic enclaves to constrain their petrogenesis. Titanites from granodiorites (G-type) and plagioclase-rich dioritic enclaves (E-type-I) present an identical U-Pb age (~ 130 Ma) and an indistinguishable wide range of Zr and total REEs contents, and Th/U ratios. However, these two types of titanites exhibit distinct micro-scale textures and geochemical compositions. G-type titanites are characterized by oscillatory zonings with two Light BSE zones (LBZ) and two or three dark BSE zones, whereas E-type-I titanites are marked by core-mantle-rim zonings. Drastic increase of LREEs, Zr, Hf, and Fe and decrease of Nb, Ta, Al, and F contents are observed in LBZ of G-type titanites, whereas remarkable reduction of LREEs, Zr, and Hf and elevation of F contents are observed from the cores to the mantles of E-type-I titanites. Based on Zr-in-titanite thermometry, G-type titanites are interpreted to have experienced twice notable temperature increase, while E-type-I titanites are inferred to have undergone a rapid cooling process. Furthermore, we suggest that the drastic chemical changes in G-type and E-type-I titanites are ascribed to early-stage magma mixing between a colder felsic magma and a Fe-, REE-rich hotter dioritic magma. Compared to G-type and E-type-I titanites, titanites from plagioclase-poor dioritic enclaves (E-type-II) are characterized by their occurrence in interstitial space and present a relatively younger U-Pb age (~ 128 Ma) and much narrower and lower range of Zr, total

  2. Drought assessment using a multivariate drought index in the Huaihe River basin of Eastern China

    Science.gov (United States)

    Li, Q.; Zeng, M.; Wang, H.; Li, P.; Wang, K.; Yu, M.

    2015-06-01

    The Huaihe River Basin having China's highest population density (662 persons per km2) lies in a transition zone between the climates of North and South China, and is thus prone to drought. Therefore, the paper aims to develop an appropriate drought assessment approach for drought assessment in the Huaihe River basin, China. Based on the Principal Component Analysis of precipitation, evapotranspiration, soil moisture and runoff, the three latter variables of which were obtained by use of the Xin'anjiang model, a new multivariate drought index (MDI) was formulated, and its thresholds were determined by use of cumulative distribution function. The MDI, the Standardized Precipitation Index (SPI) and the self-calibrating Palmer Drought Severity Index (sc-PDSI) time series on a monthly scale were computed and compared during 1988, 1999/2000 and 2001 drought events. The results show that the MDI exhibited certain advantages over the sc-PDSI and the SPI in monitoring drought evolution. The MDI formulated by this paper could provide a scientific basis for drought mitigation and management, and references for drought assessment elsewhere in China.

  3. 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

  4. Mantle-derived helium in foreland basins in Xinjiang, Northwest China

    Science.gov (United States)

    Xu, Sheng; Zheng, Guodong; Zheng, Jianjing; Zhou, Shixin; Shi, Pilong

    2017-01-01

    Hydrocarbon-rich natural gases from the Tarim, Junggar, Turpan-Hami and Santanghu basins in Xinjiang, Northwest China have measured 3He/4He ratios from 0.01 to 0.6 times higher than the atmospheric value, indicating 0-7% helium derived from the mantle. The mantle-derived helium is high in foreland basins associated with the Tianshan, Kunlun and Zhayier-Halalate orogenic mountains, but low towards the center of basins. This spatial distribution suggests that the mantle-derived helium originates either from fluids or small scale melts in the upper asthenospheric or lithospheric mantle which have found pathways into the root zones of the major faults defining these mountains, but do not significantly move into the basins themselves. During upward transport to near the surface, the mantle-derived helium is significantly diluted by radiogenic helium produced in the crust. Despite the lack of recent magmatic activity or extensional tectonics within the basins, this pattern shows strong evidence that the major faults play an important role in mantle-derived components degassing from the mantle to the surface.

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

    Directory of Open Access Journals (Sweden)

    Zhiyong Wu

    2015-01-01

    Full Text Available 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 temperature projected by the RegCM3 high-resolution regional climate model under the IPCC scenario A2. Results show that, under the scenario A2, the mean annual temperature of the basin could increase by 1.6°C, while mean annual precipitation could decrease by 2.6%. There could be an 11.6% reduction in annual runoff in the basin according to the VIC projection. However, there are marked regional variations in these climate change impacts. Reductions of 13.6%, 25.7%, and 24.6% could be expected in the regions of Hekouzhen to Longmen, Longmen to Sanmenxia, and Sanmenxia to Huayuankou, respectively. Our study suggests that the condition of water resources in the YRB could become more severe in the period from 2001 to 2030 under the scenario A2.

  6. Chemocline instability and isotope variations of the Ediacaran Doushantuo basin in South China

    Institute of Scientific and Technical Information of China (English)

    JIANG GanQing; ZHANG ShiHong; SHI XiaoYing; WANG XinQiang

    2008-01-01

    Stable isotope analyses in sections across a shelf to basinal transect of the Ediacaran Doushantuo basin show substantial isotope variabilities.In Songlin section where sediments were deposited in an intrashelf basin,δ13C values are persistently negative (-3%.to -5%.VPDB) through the entire Doushantuo Formation,similar to those obtained from the slope section in Wuhe (-5%.to -10%.,VPDB).Shallow water sections in Weng'an and Duoding show two broad δ13C anomalies overprinted with significant meter-scale variations,but none of the curves has similar absolute δ13C values compared to the Yangtze Gorges areas in South China and other sections globally.Such isotope variations,if partially recording ancient seawater signature,imply spatial and temporal chemocline instability in the Doushantuo basin.In combination with available δ13C records from other Ediacaran successions globally,the data from the Doushantuo basin are consistent,in first order,with the existence and oxidation of a large dissolved organic carbon (DOC) reservoir in Ediacaran oceans,but imply local environmental controls on Neoproterozoic isotope values and call attentions for using δ13C anomalies as time lines in stratigraphic correlation.

  7. 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.

  8. Geochemistry evidence for depositional settings and provenance of Jurassic argillaceous rocks of Jiyuan Basin, North China

    Indian Academy of Sciences (India)

    Yao Meng; Deshun Zheng; Minglong Li

    2017-02-01

    This paper aims to discuss the depositional settings and provenances for the Jurassic in Jiyuan basin, North China, based on the rare earth element (REE) and trace element features of 16 Jurassic argillaceous rock samples from the Anyao, Yangshuzhuang and Ma’ao Formations, respectively. Generally, geochemical analysis results show that chondrite-normalised REE distribution patterns of all the three formations are characterised by light-REE (LREE) enrichment, moderately negative Eu anomalies, slightly negative Ce anomalies, and strong fractionation between LREE and heavy-REE (HREE). Trace element proxies V/(V+Ni), Ceanom index, Ce/La, Sr/Ba, and Sr/Cu indicate a weak oxidation–reduction environment, progressively decreasing reducibility and water depth from the bottom up during Jurassic in Jiyuan basin. Palaeoclimate varied from humid in the Early Jurassic to arid in the Middle Jurassic, corresponding with the variations of palaeoredox and palaeosalinity. The provenances of Jurassic rocks in Jiyuan basin are mainly from felsic sources related to active continental margin and continental island arc. The Early–Middle Jurassic (Anyao and Yangshuzhuang Formations) provenances are mainly derived from North Qinling and partially from the eroded recycled felsic sedimentary covers of Taihang Mountain. In the late stage of Middle Jurassic (Ma’ao Formation), Taihang Mountain has been the primary source to Jiyuan basin. We conclude that the Jurassic rocks of Jiyuan basin reveal the progressive uplift and denudation processes of the Taihang Mountain.

  9. 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.

  10. 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

  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. Mechanism of petroleum migration and accumulation in western China's superposed basins

    Institute of Scientific and Technical Information of China (English)

    Kang Yongshang; Li Peijun; Qi Xuefeng; Wen Yonghong; Li Shuijing

    2012-01-01

    In western China.most petroliferous basins are superposed due to their multi-periodic tectonic evolution,and the mechanisms of petroleum migration and accumulation are so complex that much more sophisticated methodologies are necessary for depiction of these mechanisms and identification of petroleum occurrences.For this purpose,in this article,a new methodology was formulated which includes:(1) vertical identification of petroleum migration and accumulation fluid dynamic systems in the superposed basins;(2) analysis of the effect of large scale regional faults and fault combinations on the fluids exchange between the vertically identified different systems;(3) analysis of petroleum migration and accumulation in each vertically identified system,and establishment of appropriate geological model of petroleum migration and accumulation for each vertically identified system.Using this methodology,the satisfactory results obtained in the Lunnan Uplift of Tarim Basin and Ludong Uplift of Jungar Basin case studies are:(1) existence of different vertical fluid dynamic systems in western China's superposed basins which are very necessary for understanding the mechanism of petroleum migration and accumulation;(2) in deep system,long-distance lateral petroleum migration and accumulation mainly take place along the long time exposed unconformity with weathered,fractured or karst reservoir rocks;(3) regional faults are the main conducts for fluids migration from deep system up to middle and/or upper systems.As to middle and/or upper systems,regional faults play a role of "petroleum source".Small faults within middle and/or upper systems conduct petroleum to carrier beds with less impeding force;(4) petroleum migrated from deep system vertically up to middle and/or upper systems will migrate laterally in carrier beds of these systems and accumulate to form pools near or far from faults.

  13. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    Science.gov (United States)

    Wang, Jingzhong; Jia, Hongjuan

    2016-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  14. Organic petrology and geochemistry of mudrocks from the lacustrine Lucaogou Formation, Santanghu Basin, northwest China: Application to lake basin evolution

    Science.gov (United States)

    Hackley, Paul C.; Fishman, Neil; Wu, Tao; Baugher, Gregory

    2016-01-01

    Exploration for tight oil in the frontier Santanghu Basin of northwest China has resulted in recent commercial discoveries sourced from the lacustrine Upper Permian Lucaogou Formation, already considered a “world class source rock” in the Junggar Basin to the west. Here we apply an integrated analytical program to carbonate-dominated mudrocks from the Lucaogou Formation in Santanghu Basin to document the nature of organic matter (OM) in the context of an evolving lake system. The organic-rich samples (TOC 2.8–11.4 wt%; n = 10) were widely spaced from an ~ 200 m cored section, interpreted from textural and mineralogical evidence to document transition from a lower under-filled to an overlying balanced-filled lake. Organic matter is dominated by moderate to strongly fluorescent amorphous material with Type I geochemical signature (HI values 510–755; n = 10) occurring in a continuum from lamellar stringers, 10–20 μm thick, some ≥ 1 mm in length (possible microbial mat; preserved only in lower under-filled section) to finely-disseminated amorphous groundmass intimately intermixed with mineral matrix. Biomarkers for methanotrophs and photosynthetic cyanobacteria indicate a complex microbial consortium. A unicellular prasinophyte green alga(?), similar to Tasmanites in marine rocks, is present as discrete flattened discs 50–100 μm in diameter. Type III OM including vitrinite (some fluorescent) and inertinite also is abundant. Solid bitumen, indicating local kerogen conversion, fills voids and occurs throughout the cored section. Vitrinite reflectance values are 0.47–0.58%, consistent with strong OM fluorescence but may be “suppressed”. Other proxies, e.g., biomarker parameters, indicate the Lucaogou Formation is in the early oil window at this location. On average, slightly more amorphous OM and telalginite are present in the lower section, consistent with a shallow, stratified, saline environment with low sediment dilution. More

  15. Geological, geochronological, geochemical, and Sr-Nd-O-Hf isotopic constraints on origins of intrusions associated with the Baishan porphyry Mo deposit in eastern Tianshan, NW China

    Science.gov (United States)

    Wang, Yinhong; Xue, Chunji; Liu, Jiajun; Zhang, Fangfang

    2016-10-01

    The Baishan porphyry Mo deposit (0.72 Mt; 0.06 % Mo) is located in the interior of the eastern Tianshan orogenic belt in Xinjiang, NW China. The deposit comprises 15 orebodies that are associated with monzogranite and granite porphyry stocks and are structurally controlled by roughly EW-trending faults. Secondary ion mass spectrometry (SIMS) zircon U-Pb dating of the monzogranite and granite porphyry yielded the Middle Triassic age (228 ± 2 to 227 ± 2 Ma), which coincide with the molybdenite Re-Os model ages ranging from 226 ± 3 to 228 ± 3 Ma. The Triassic monzogranite and granite porphyry belong to high-K calc-alkaline series and are characterized by high SiO2 and Al2O3 and low MgO, TiO2, and P2O5 concentrations, with negative Eu anomalies (δEu = 0.55-0.91). The least-altered monzogranite and granite porphyry yield uniform ɛ Nd( t) values from +1.6 to +3.6, and wide (87Sr/86Sr) i ratios ranging between 0.7035 and 0.7071, indicating that they were derived from the lower crust. In situ O-Hf isotopic analyses on zircon using SIMS and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) indicate that the δ18O and ɛ Hf( t) values of zircon from a monzogranite sample vary from 6.1 to 7.3 ‰ and +8.0 to +11.7, respectively, whereas zircon from a granite porphyry sample vary from 6.2 to 6.9 ‰ and +7.3 to +11.2, respectively. The geochemical and isotopic data imply that the primary magmas of the Baishan granite were likely derived from partial melts from the lower crust involving some mantle components. The Baishan Mo deposit and granitic emplacement were proposed to be most likely related to post-orogenic lithospheric extension and magmatic underplating. An extensional event coupled with the rising of hot mantle-derived melts triggered partial melting of the lower crust, as well as provided metals (Mo).

  16. Plastic Deformation and Seismic Properties in Fore-arc Mantles: A Petrofabric Analysis of the Yushigou Harzburgites, North Qilian Suture Zone, NW China

    Science.gov (United States)

    Cao, Y.; Jung, H.; Song, S.; Park, M.; Jung, S.; Lee, J.

    2015-12-01

    The fore-arc mantle above a subducting slab is a unique site where complex partial melting, melt/fluid-rock interaction, and deformation of mantle rocks occur. To constrain these processes, we analyzed the deformation microstructures, crystal preferred orientations (CPO), and water content in natural harzburgites that occur as exhumed massifs in the North Qilian suture zone, NW China. These harzburgites are very fresh, and have mineral assemblages of olivine ( 81‒87 vol.%), orthopyroxene ( 11‒17 vol.%), clinopyroxene ( 1‒2 vol. %), and spinel ( 1 vol.%). Detailed analyses of mineral textures, CPO patterns, and rotation axis distributions suggested that the plastic deformation of olivine and pyroxene were accommodated by activating a series of slip systems of dislocation. The olivine (A-/D-type fabric) showed dominant (010)[100] and/or (001)[100] slip systems, as well as other minor [100]-glide, {0kl}[100], and [001]-glide slip systems. The orthopyroxene showed dominant (100)[001] and subordinate (010)[001] slip systems, with minor (100)[010], (100)[0vw] slip systems. The water content was extremely low in the orthopyroxene (38‒44 wt. ppm), equilibrated olivine (4‒7 wt. ppm), and bulk-rock samples (9‒14 wt. ppm). Integrated with the previously reported refractory mineral and whole-rock compositions (Song et al., 2009), as well as the estimated low pressure ( 1‒2 GPa), high temperature ( 1100‒1300 °C), low stress ( 1‒4 MPa), and water-poor conditions of deformation, it is concluded that these harzburgites represent a remnant of a fossil fore-arc lithospheric mantle which was probably both formed and deformed in a young and warm fore-arc mantle setting (i.e. infant subduction zone). Based on these results, a refined schematic model of olivine fabric distributions in subduction zones was proposed. In this model, the opposing polarizing directions of A-/D-type olivine fabrics (prevalent in the fore-arc lithospheric mantle) with other underlying

  17. Sr-Nd-Pb isotopic compositions of the lower crust beneath northern Tarim: insights from igneous rocks in the Kuluketage area, NW China

    Science.gov (United States)

    Zhang, Yan; Wei, Xun; Xu, Yi-Gang; Long, Xiao-Ping; Shi, Xue-Fa; Zhao, Jian-Xin; Feng, Yue-Xing

    2016-09-01

    The composition of lower crust of the Tarim Craton in NW China is essential to understand the petrogenesis of the ~290-275 Ma Tarim basalts and associated intermediate-felsic rocks. However, it remains poorly constrained because extremely sparse granulite terrains or granulite xenoliths have been found in the Tarim Craton. New trace element and Sr-Nd-Pb isotopic data are reported for the Neoarchean and Neoproterozoic igneous rocks widely distributed in the northern margin of the Tarim Craton. The Neoarchean granitic gneisses show fractionated REE (rare earth element) patterns [(La/Yb) N = 12-58, YbN = 10.6-36] with pronounced negative Nb-Ta and Ti anomalies. These features, together with negative ɛNdi (-0.7 to -3.2) suggest that they were derived from melting of mafic lower crust. The Neoproterozoic biotite granodiorites are strongly depleted in HREE with (La/Yb) N up to 55. They are characterized by high Sr (671-789 ppm) but very low Y (7.10-8.06 ppm) and Yb contents (0.47-0.58 ppm), showing typical features of adakitic rocks. The samples with different SiO2 contents display identical 87Sr/86Sri (0.7101-0.7103), ɛNdi (-14.1 to -15.7) and Pb isotopes (208Pb/204Pbi = 36.94-37.07). These features together with arc-like trace element patterns suggest that they were derived from melting of thickened lower crust. In comparison, the Neoproterozoic hornblende-biotite granodiorites have similar trace element compositions except for weaker depletion in HREE and have lower 87Sr/86Sri (0.7078) and initial Pb isotopes, and higher ɛNdi (-12.3 to -12.7). This suggests that they were formed by melting of old lower continental crust at a shallower depth than the biotite granodiorites. These rocks were derived from the lower crust, thus providing valuable information on the nature of the lower crust beneath northern Tarim. Combined with published data, the 87Sr/86Sri, ɛNdi, 206Pb/204Pbi and ɛHfi of the northern Tarim lower crust ranges from 0.7055 to 0.7103, from -12 to -17

  18. Late Permian to Early Oligocene granitic magmatism of the Phan Si Pan uplift area, NW Vietnam: their relationship to Phanerozoic crustal evolution of Southwest China

    Science.gov (United States)

    Pham, T. T.; Shellnutt, G.

    2015-12-01

    The Phan Si Pan uplift area of NW Vietnam is a part of the Archean to Paleoproterozoic Yangtze Block, Southwest China. This area is of particular interest because it experienced a number of Phanerozoic crustal building events including the Emeishan Large Igneous Province, the India-Eurasia collision and Ailaoshan - Red River Fault displacement. In the Phan Si Pan uplift area, there are at least three different geochronological complexes, including: (1) Late Permian, (2) Eocene and (3) Early Oligocene. (1) The Late Permian silicic rocks are alkali ferroan A1-type granitic rocks with U/Pb ages of 251 ± 3 to 254 ± 3 Ma. The Late Permian silicic rocks of Phan Si Pan uplift area intrude the upper to middle crust and are considered to be part of the ELIP that was displaced during the India-Eurasian collision along the Ailaoshan-Red River Fault shear zone and adjacent structures (i.e. Song Da zone). Previous studies suggest the Late Permian granitic rocks were derived by fractional crystallization of high - Ti basaltic magma. (2) The Eocene rocks are alkali ferroan A1-type granites (U/Pb ages 49 ± 0.9 Ma) and are spatially associated with the Late Permian granitic rocks. The trace element ratios of this granite are similar to the Late Permian rocks (Th/Nb=0.2, Th/Ta = 2.5, Nb/U = 24, Nb/La =1.2, Sr/Y=1). The origin of the Eocene granite is uncertain but it is possible that it formed by fractional crystallization of a mafic magma during a period of extension within the Yangtze Block around the time of the India-Eurasia collision. (3) The Early Oligocene granite is characterized as a peraluminous within-plate granite with U/Pb ages of 31.3 ± 0.4 to 34 ± 1 Ma. The Early Oligocene granite has trace element ratios (Th/Nb = 2.1, Th/Ta = 22.6, Nb/U = 4.4, Nb/La = 0.4, Sr/Y = 60.4) similar to crust melts. The high Sr/Y ratio (Sr/Y = 20 - 205) indicates a lower crust source that was garnet-bearing. The Phan Si Pan uplift was neither a subduction zone nor an arc environment

  19. Geomorphic assessment of the tectonic activity of Qiulitagh fold-belt, Kuqa foreland basin, Xinjiang, China

    Science.gov (United States)

    Saint Carlier, Dimitri; Graveleau, Fabien; Delcaillau, Bernard; Hurtrez, Jean-Emmanuel; Vendeville, Bruno

    2014-05-01

    The Qiulitagh fold belt is an anticline structure located in the Kuqa fold-and-thrust belt (southern Tian Shan, China), whose active folding is well documented by structural and palaeomagnetic studies (Chen et al., 2007; Hubert-Ferrari et al., 2007; Li et al., 2012; Wang et al., 2011). The topography of Quilitagh fold belt can be divided into two SW-NE parallel ridges: 1) a 90 km long northern ridge, composed of the Northern Qiulitagh anticline and the Yakelike anticline, and 2) a 165km long southern ridge, composed of the Southern Qiulitagh anticline and the Mishikantage anticline. Due to the current absence of vegetation and relative homogeneity of outcropping lithologies (mainly Neogene detrital sandstone and silstone), these anticlines provide exceptional field cases for investigating the dynamic relationships between fold growth mechanisms, the subsurface structures, the geomorphic entities and the drainage network evolution. We used free topographic and satellite image datasets to carry out a morphometric study of the Quilitagh fold-belt and investigate the kinematics of active folding. Topographic datasets include Digital Elevation Models (DEM) from the NASA SRTM V.4.0 and ASTER programs, whereas satellite images are extracted from Landsat 7 shots and Google Earth. These datasets were incorporated in GIS software where three scales of observation were investigated: 1) a global fold scale, 2) a drainage basin scale and 3) a valley scale. At the drainage basin scale, we selected about 250 items and quantified several geomorphic indices of relative active tectonic growth. These are the basin mean slope, hypsometric integral, basin asymmetry and local relief. We also used published seismic profiles to link the 3D subsurface geometry of the salt-related Qiulitagh fold belt with the geomorphic signal. Results indicate that the morphometry of Quilitagh drainage basins (hypsometry, drainage basin asymmetry, local relief, valley incision, steepness index) change

  20. Drought Trends and Temperature Influence in Zhanghe River Basin, China

    Directory of Open Access Journals (Sweden)

    Bakhtawar Wagan

    2015-01-01

    Full Text Available 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 with different frequency and magnitude was increased over last decades (2000–2010 at most of the stations. Statistical results demonstrated that temperature was decreased in the 1st decade in most of stations but in two decades from 1990 to 2000 and 2001 to 2010, temperature was increased except in Changzhi station. These results could be a future reference for developing information programs about monitoring and early drought information, planning of existing reservoirs, and management of water resources under climate conditions.

  1. Pseudofaults and associated seamounts in the conjugate Arabian and Eastern Somali basins, NW Indian Ocean- New constraints from high-resolution satellite-derived gravity data

    Digital Repository Service at National Institute of Oceanography (India)

    Sreejith, K.M.; Chaubey, A.K.; Mishra, A.; Kumar, S.; Rajawat, A.S.

    to the west. Plateau, CR = Comorin Ridge.Earth Sciences 131 (2016) 1–11In the Arabian Basin, water depth and sediment thickness varies from 3.4 km to 4.3 km and from 1.3 km to 4.2 km respectively. Whereas, in the Eastern Somali Basin, water depth varies from 3... stream_size 45417 stream_content_type text/plain stream_name J_Asian_Earth_Sci_131_1.pdf.txt stream_source_info J_Asian_Earth_Sci_131_1.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 n – va a r t i...

  2. Effects of Crop Growth on Hydrological Pro cesses 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 RegCM3−CERES model, was used to study the effects 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, Songhua jiang River Basin and Pearl River Basin. When compared with the RegCM3 control run, RegCM3−CERES reduced the negative biases of monthly mean temper-ature 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 (runoff, evapotranspiration and to-tal precipitation) over all seven basins indicate that changes of evapotranspiration agree well with total precipitation. Compared to the RegCM3, RegCM3−CERES 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 m2 m−2), greater root soil moisture (0.01 m3 m−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.

  3. Miocene to present-day shortening and intermontane basin formation in the Andean Puna Plateau, NW Argentina (24°30'S)

    Science.gov (United States)

    Strecker, M. R.; Bookhagen, B.; Alonso, R. N.; Pingel, H.; Freymark, J.

    2015-12-01

    With average elevations of about 3.7 km the Altiplano-Puna Plateau of the southern central Andes constitutes the world's second largest orogenic plateau. The plateau generally consists of internally drained, partly coalesced sedimentary basins bordered by reverse-fault bounded ranges, >5 km high. In the Puna, the Argentine sector of the plateau, active tectonism has been interpreted to be characterized by a low level of strike-slip and normal faulting associated with mafic volcanism. In contrast, the eastern plateau margins and the adjacent foreland record a higher level of seismicity and ongoing contraction. Despite ubiquitous Plio-Pleistocene normal faulting along the eastern plateau margins, our new observations record contraction in the plateau interior. Fanning of E-dipping Miocene sedimentary strata involved in the formation of an anticline in the Pocitos Basin of the central Puna interior indicates growth, which must have begun after 7 Ma; 1.5-m.y.-old lacustrine strata as well as tilted Pleistocene lacustrine shorelines associated with this structure indicate sustained uplift into the Quaternary. Corresponding observations along the eastern border of the Pocitos Basin show that <3.5-m.y.-old strata are involved in contractile deformation and basin compartmentalization. Shortening in the central Puna is compatible with Plio-Pleistocene shortening in the low-elevation Salar de Atacama farther west, and may indicate that low-elevation sectors of the plateau have not yet reached a critical elevation that is conducive to normal faulting as observed elsewhere. The onset of extensional deformation in the Puna is thus highly disparate in space and time. Coeval regional thrusting, strike-slip, and normal faulting do not support a structural and topographic setting that promotes wholesale extension and orogenic collapse of the plateau realm.

  4. [Ecosystem's soil conservation function and its spatial distribution in Lancang River Basin, Southwest China].

    Science.gov (United States)

    Chen, Long; Xie, Gao-Di; Pei, Sha; Zhang, Chang-Shun; Fan, Na; Zhang, Cai-Xia; Li, Shi-Mei

    2012-08-01

    Based on the RUSLE model, this paper analyzed the ecosystem's soil conservation function and its spatial distribution in Lancang River Basin. This Basin could be one of the regions having the highest ecosystem' s soil conservation capability in China, with an annual ecosystem's soil conservation amount being 2.36 x 10(10) t x a(-1) and the soil conservation amount per unit area being 1453.72 t x a(-1) per hectare. The total amounts of the N, P, and K conserved in soils were 5.74 x 10(7), 3.07 x 10(7), and 3.75 x 10(8) t x a(-1), respectively, and presented an increasing trend from upstream to downstream. Among the ecosystems in the Basin, forest ecosystem had the highest soil conservation capability, followed by grassland and farmland, while desert ecosystem had the lowest one. The soil conservation capability of the ecosystems was linearly increased with the increase of vegetation coverage. Averagely, a 10% increment in the vegetation coverage could result in a 35.3% increment in soil conservation capability. To rationally increase the vegetation coverage by reliable ecosystem management based on local conditions would make good effect in preventing soil erosion and maintaining soil nutrients in the Basin.

  5. Formation Models and Distribution of Oil and Gas Pools in Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    Long Shengxiang

    2008-01-01

    This article reports the main formation models and distribution of the oil and gas pools in Tarim basin,China,including (I) occurrence of the found oil and gas pools,(2) main formation models of oil and gas pools,and (3) distribution law of oil/gas pools.Petroleum is distributed widely in the strata of Tarim basin from the Sinian at the bottom to the Neogene at the top.However,the found oil and gas fields are mainly distributed in Shaya (沙雅) uplift,Tazhong (塔中) uplift,and Kuche (库车)depression.This article presents 4 main formation models,namely,early formation and long-term preservation,early formation and late reformation,middle-late multiphase-multisource formation,late single-stage formation.Tarim basin is very rich in petroleum resources.Long-term inherited intrabasinal paleohighs and slope zones are the most favorable areas for accumulation of hydrocarbons,but the types of oil and gas pools are different from area to area.The control of unconformities and faults on hydrocarbon accumulating is prominent in Tarim basin.Preservation conditions are of utmost importance.Formation of some oil and gas pools is the result of reforming and re-accumulating of early accumulated hydrocarbons.

  6. The down-faulted basin zone and high disaster risk zone in Shanxi Province, China

    Institute of Scientific and Technical Information of China (English)

    刘惠敏; 苏桂武; 邓砚; 高庆华

    2004-01-01

    Shanxi Province is a region with frequent occurrence of earthquakes, floods and waterlogging, meteorological and geologic hazards, and agrobiohazards in China. The study shows that the formation and development of the down-faulted basin zone in Shanxi Province provides an available condition for preparation and occurrence of these hazards, so that the basin zone becomes an area with frequent occurrence of the hazards, such as earthquakes, floods and waterlogging, meteorological and geologic hazards and agrobiohazards in Shanxi and with their most serious interaction and mutual intensification. Moreover, the basin zone is an area with dense population and most concentrated industrial and agricultural productions and social-economic property in Shanxi. The comprehensive effect of the two factors caused the zone to be a high natural disaster risk area in Shanxi. For reduction of natural disasters and ensuring the sustainable social-economic development in Shanxi, it is necessary to regard the basin zone as an important area for disaster reduction in Shanxi and to carry out integrated disaster reduction.

  7. Modeling Ecohydrological Processes and Spatial Patterns in the Upper Heihe Basin in China

    Directory of Open Access Journals (Sweden)

    Bing Gao

    2015-12-01

    Full Text Available The Heihe River is the second largest inland basin in China; runoff in the upper reach greatly affects the socio-economic development in the downstream area. The relationship between spatial vegetation patterns and catchment hydrological processes in the upper Heihe basin has remained unclear to date. In this study, a distributed ecohydrological model is developed to simulate the hydrological processes with vegetation dynamics in the upper Heihe basin. The model is validated by hydrological observations at three locations and soil moisture observations at a watershed scale. Based on the simulated results, the basin water balance characteristics and their relationship with the vegetation patterns are analyzed. The mean annual precipitation and runoff increase with the elevation in a similar pattern. Spatial patterns of the actual evapotranspiration is mainly controlled by the precipitation and air temperature. At the same time, vegetation distribution enhances the spatial variability of the actual evapotranspiration. The highest actual evapotranspiration is around elevations of 3000–3600 m, where shrub and alpine meadow are the two dominant vegetation types. The results show the mutual interaction between vegetation dynamics and hydrological processes. Alpine sparse vegetation and alpine meadow dominate the high-altitude regions, which contribute most to the river runoff, and forests and shrub contribute relatively small amounts of water yield.

  8. 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.

  9. 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.

  10. ESR dating of the Majuangou and Banshan Paleolithic sites in the Nihewan Basin, North China.

    Science.gov (United States)

    Liu, Chun-Ru; Yin, Gong-Ming; Deng, Cheng-Long; Han, Fei; Song, Wei-Juan

    2014-08-01

    The fluvio-lacustrine sequences in the Nihewan Basin, northern China provide an important source of Paleolithic settlements and therefore early human occupation in the eastern Old World. Here we present electron spin resonance (ESR) chronology for the Majuangou (MJG-III, MJG-II and MJG-I) and Banshan (BS) Paleolithic sites in this basin by the quartz Ti-Li center ESR dating. Results show that the ages of MJG-III and MJG-II could be estimated to be ∼1.70 Ma (millions of years ago); of MJG-I, ∼1.40 Ma; and BS, ∼1.35 Ma. This ESR chronology is consistent with the previous magnetochronology, thus providing strong support for the earliest human presence at the high northern latitudes of Northeast Asia.

  11. Detecting Variation Trends of Temperature and Precipitation for the Dadu River Basin, China

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2016-01-01

    Full Text Available This study analyzes the variation trends of temperature and precipitation in the Dadu River Basin of China based on observed records from fourteen meteorological stations. The magnitude of trends was estimated using Sen’s linear method while its statistical significance was evaluated using Mann-Kendall’s test. The results of analysis depict increase change from northwest to southeast of annual temperature and precipitation in space. In temporal scale, the annual temperature showed significant increase trend and the annual precipitation showed increase trend. For extreme indices, the trends for temperature are more consistent in the region compared to precipitation. This paper has practical meanings for an effective management of climate risk and provides a foundation for further study of hydrological situation in this river basin.

  12. 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.

  13. 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.

  14. Comparative Study of Basins within Palaeogene Seaway in East China and Cretaceous Seaway in North America and Its Reservoir Significance

    Institute of Scientific and Technical Information of China (English)

    Wu Xiantao

    2007-01-01

    The well known Cretaceous seaway in North America was recognized in the middle of the last century and the Palaeogene seaway in East China was proposed by the author recently. The two seaways located on the opposite sides of North Pacific Ocean may be not a coincidence,and a comparative study was made in this paper. The results show that the two seaways inundated basins share several similarities particularly in basin origin,filling processes and reservoir facies. It is suggested that reservoir facies of estuarine sandstone and shelf bar sandstone related to sea level fluctuation,which are well developed in the Cretaceous seaway covered basins in North America might have been also developed here in Palaeogene seaway inundated basins in East China. Therefore it is worth paying more attention to finding these new reservoir facies on this side of the Pacific ocean. Evidences of sedimentology and ichnology indicate that good prospects are likely.

  15. 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.

  16. NW CSC annual report fiscal year 2013

    Science.gov (United States)

    Bisbal, Gustavo A.

    2013-01-01

    The Northwest Climate Science Center (NW CSC) was established in 2010 as one of eight regional Climate Science Centers created by the Department of the Interior (DOI). The NW CSC encompasses Washing-ton, Oregon, Idaho, and western Montana and has overlapping boundaries with three Landscape Conservation Cooperatives (LCCs): the Great Northern, the Great Basin, and the North Pacific. With guidance from its Executive Stakeholder Advisory Committee (ESAC), the NW CSC and its partner LCCs are addressing the highest priority regional climate science needs of Northwest natural and cultural resource managers. Climate Science Centers tap into the scientific expertise of both the U.S. Geological Survey (USGS) and academic institutions. The NW CSC is supported by an academic consortium with the capacity to generate climate science and tools in a coordinated fashion, serving stakeholders across the Northwest region. This consortium is primarily represented by Oregon State University (OSU), the University of Id-ho (UI), and the University of Washington (UW). The academic consortium and USGS provide capabilities in climate science, ecology, impacts and vulnerability assessment, modeling, adaptation planning, and advanced information technology, all necessary to address and respond to climate change in the Northwest. University members also recruit and train graduate students and early-career scientists. This Annual Report summarizes progress for the goals set out in the NW CSC Strategic Plan for 2012-2015 (http://www.doi.gov/csc/northwest/upload/Northwest-CSC-Strategic-Plan.cfm) and the NW CSC Work-plan for Fiscal Year (FY) 2013 (October 1, 2012 through September 30, 2013). The report follows the structure of the Strategic Plan, which describes the five core services (Executive, Science, Data, Communications, and Education and Training) provided by the NW CSC in support of the stated vision: Our Vision: To become nationally recognized as a best-practice model for the provision

  17. Integrated Analysis on Gravity and Magnetic Fields of the Hailar Basin, NE China: Implications for Basement Structure and Deep Tectonics

    Science.gov (United States)

    Sun, B.; Wang, L.; Dong, P.; Scientific Team Of Applied Geophysics

    2010-12-01

    The Hailar Basin is one of the most representative basins among the Northeast China Basin Group, which is situated in the east of East Asia Orogene between the Siberia Plate and the North China Plate. Based on the detailed analysis of the Bouguer gravity anomaly, aeromagnetic anomaly as well as petrophysical data, we studied the features of gravity-magnetic fields in the basin and its neighboring areas. A combined approach of Wavelet Multi-scale Decomposition and Power Spectrum Analysis was adopted to quantitatively grade the gravity and magnetic anomalies into four levels. Accordingly, the apparent depths of the source fields can be assessed. The results reveal the crustal density and magnetic structures of the Hailar Basin. Low-order wavelet details of gravity-magnetic anomalies were carried out on studying basin basement structure. Seven major basement faults of the basin were identified, and the basement lithology was discussed and predicted. Three major uplifts and 14 depressions were delineated according to basement depth inversion by the Park method. High-order wavelet approximations of gravity-magnetic anomalies were carried out on studying deep tectonics of the basin. The average Moho depth of the study area is about 40 km, with a mantle uplift located in the northeast of the basin. The average depth of the Curie interface is about 19 km, while the uplift of the Curie interface is in the basin center and its east and west sides are depressions. Finally, inversion of Bouguer gravity anomalies was conducted on an across-basin GGT profile using the Wavelet Multi-scale Decomposition. The inversion results are consistent with those of GGT seismic inversion, suggesting that the Wavelet Multi-scale Decomposition can be applied to distinguish major crustal density interfaces.

  18. Meso-Cenozoic Tectono-Thermal Evolution History in Bohai Bay Basin, North China

    Institute of Scientific and Technical Information of China (English)

    Yinhui Zuo; Nansheng Qiu; Jiawei Li; Qingqing Hao; Xiongqi Pang; Zhongying Zhao; Qi Zhu

    2015-01-01

    The thermal history of sedimentary basins is a key factor for hydrocarbon accumula-tion and resource assessment, and is critical in the exploration of lithospheric tectono-thermal evo-lution. In this paper, the Cenozoic thermal histories of nearly 200 wells and the Mesozoic thermal histories of 15 wells are modeled based on the vitrinite reflectance and apatite fission track data in Bohai Bay Basin, North China. The results show that the basin experienced Early Cretaceous and Paleogene heat flow peaks, which reveals two strong rift tectonic movements that occurred in the Cretaceous and the Paleogene in the basin, respectively. The thermal evolution history in Bohai Bay Basin can be divided into five stages including (1) the low and stable heat flow stage from the Trias-sic to the Jurassic, with the heat flow of 53 to 58 mW/m2;(2) the first heat flow peak from the Early Cretaceous to the middle of the Late Cretaceous, with a maximum heat flow of 81 to 87 mW/m2;(3) the first post-rift thermal subsidence stage from the middle of the Late Cretaceous to the Paleocene, with the heat flow of 65 to 74 mW/m2 at the end of the Cretaceous; (4) the second heat flow peak from the Eocene to the Oligocene, with a maximum heat flow of 81 to 88 mW/m2;and (5) the second thermal subsidence stage from the Neogene to present, with an average heat flow of 64 mW/m2.

  19. Multimedia fate modeling and risk assessment of a commonly used azole fungicide climbazole at the river basin scale in China.

    Science.gov (United States)

    Zhang, Qian-Qian; Ying, Guang-Guo; Chen, Zhi-Feng; Liu, You-Sheng; Liu, Wang-Rong; Zhao, Jian-Liang

    2015-07-01

    Climbazole is an antidandruff active ingredient commonly used in personal care products, but little is known about its environmental fate. The aim of this study was to evaluate the fate of climbazole in water, sediment, soil and air compartments of the whole China by using a level III multimedia fugacity model. The usage of climbazole was calculated to be 345 t in the whole China according to the market research data, and after wastewater treatment a total emission of 245 t was discharged into the receiving environment with approximately 93% into the water compartment and 7% into the soil compartment. The developed fugacity model was successfully applied to estimate the contamination levels and mass inventories of climbazole in various environmental compartments of the river basins in China. The predicted environmental concentration ranges of climbazole were: 0.20-367 ng/L in water, and 0.009-25.2 ng/g dry weight in sediment. The highest concentration was mainly found in Haihe River basin and the lowest was in basins of Tibet and Xinjiang regions. The mass inventory of climbazole in the whole China was estimated to be 294 t, with 6.79% in water, 83.7% in sediment, 9.49% in soil, and 0.002% in air. Preliminary risk assessment showed high risks in sediment posed by climbazole in 2 out of 58 basins in China. The medium risks in water and sediment were mostly concentrated in north China. To the best of our knowledge, it is the first report on the emissions and multimedia fate of climbazole in the river basins of the whole China.

  20. Carbonate- and silicate-rich globules in the kimberlitic rocks of northwestern Tarim large igneous province, NW China: Evidence for carbonated mantle source

    Science.gov (United States)

    Cheng, Zhiguo; Zhang, Zhaochong; Santosh, M.; Hou, Tong; Zhang, Dongyang

    2014-12-01

    We report carbonate- and silicate-rich globules and andradite from the Wajilitage kimberlitic rocks in the northwestern Tarim large igneous province, NW China. The carbonate-rich globules vary in size from 1 to 3 mm, and most have ellipsoidal or round shape, and are composed of nearly pure calcite. The silicate-rich globules are elliptical to round in shape and are typically larger than the carbonate-rich globules ranging from 2 to several centimeters in diameter. They are characterized by clear reaction rims and contain several silicate minerals such as garnet, diopside and phlogopite. The silicate-rich globules, reported here for the first time, are suggested to be related to the origin of andradite within the kimberlitic rocks. Our results show that calcite in the carbonate-rich globules has a high XCa (>0.97) and is characterized by extremely high concentrations of the total rare earth elements (up to 1500 ppm), enrichment in Sr (8521-10,645 ppm) and LREE, and remarkable depletion in Nd, Ta, Zr, Hf and Ti. The calcite in the silicate-rich globules is geochemically similar to those in the carbonate-rich globules except the lower trace element contents. Garnet is dominantly andradite (And59.56-92.32Grs5.67-36.03Pyr0.36-4.61Spe0-0.33) and is enriched in light rare earth elements (LREEs) and relatively depleted in Rb, Ba, Th, Pb, Sr, Zr and Hf. Phlogopite in the silicate-rich globules has a high Mg# ranging from 0.93 to 0.97. The composition of the diopside is Wo45.82-51.39En39.81-49.09Fs0.88-0.95 with a high Mg# ranging from 0.88 to 0.95. Diopside in the silicate-rich globules has low total rare earth element (REE) contents (14-31 ppm) and shows middle REE- (Eu to Gd), slight light REE- and heavy REE-enrichment with elevated Zr, Hf and Sr contents and a negative Nb anomaly in the normalized diagram. The matrix of the kimberlitic rocks are silica undersaturated (27.92-29.31 wt.% SiO2) with low Al2O3 (4.51-5.15 wt.%) and high CaO (17.29-17.77 wt.%) contents. The

  1. A Late Carboniferous-Early Permian slab window in the West Junggar of NW China: Geochronological and geochemical evidence from mafic to intermediate dikes

    Science.gov (United States)

    Yin, Jiyuan; Long, Xiaoping; Yuan, Chao; Sun, Min; Zhao, Guochun; Geng, Hongyan

    2013-08-01

    The Late Carboniferous to Early Permian is a critical period for the formation of particular high-temperature magmatic associations in West Junggar, NW China and the geodynamic processes of ridge subduction and related slab windows in the Central Asian Orogenic Belt. Mafic to intermediate dikes, exposed in the central and southeastern West Junggar extensively, mainly consist of Nb-enriched and magnesian suites. The Nb-enriched dikes (305 Ma) are characterized by high Nb contents (5.63-9.08 ppm) and large variations of major element contents, exhibiting high-K to medium-K calc-alkaline characteristics with high Na2O/K2O (1.33-3.85) and low Sr/Y (9-32) ratios. The dikes have moderate Mg# (44.6-52.9), LREE-rich and sub-horizontal HREE patterns ((La/Yb)N = 3.05-7.18; (Gd/Yb)N = 1.43-1.78) with weak Eu anomalies (Eu*/Eu = 0.81-1.10) and positive εNd (t) values (+ 5.2 to + 8.0), and likely originate from partial melting of mantle peridotite that was metasomatized by subducted sediment-derived melts and slab fluids. The medium-K magnesian dikes (305 Ma) are characterized by high MgO (3.05-7.28 wt.%), Cr (22.3-311 ppm) and Ni (32.6-199 ppm) contents and all plot in the field of high-Mg andesite. Some have very high Mg numbers (Mg# > 60), suggesting a primitive melt composition. These samples display positive Ba, Sr, K and negative Nb-Ta-Ti anomalies as well as strongly-depleted HREE patterns with weak positive Eu anomalies. They have high Sr/Y (27-126) and relatively high εNd (t) values (+ 6.0 to + 8.3), which suggest a similar petrogenesis as the Nb-enriched dikes, but were metasomatized by adakitic melts. The high-K magnesian dikes (284 Ma) are high-K calc-alkaline and have lower MgO (3.63-5.57 wt.%) compared with the medium-K suite. They have high Sr (422-819 ppm), Sr/Y (26-62) ratios and εNd (t) values (+ 7.0 to + 7.1) with relatively flat REE patterns ((La/Yb)N = 2.4-5.5), probably originating from partial melting of K-enriched mantle wedge peridotite metasomatized

  2. An evaluation of the effect of future climate on runoff in the Dongjiang River basin, South China

    OpenAIRE

    K. Lin; Zhai, W; Huang, S.; Liu, Z.

    2015-01-01

    The impact of future climate change on the runoff for the Dongjiang River basin, South China, has been investigated with the Soil and Water Assessment Tool (SWAT). First, the SWAT model was applied in the three sub-basins of the Dongjiang River basin, and calibrated for the period of 1970–1975, and validated for the period of 1976–1985. Then the hydrological response under climate change and land use scenario in the next 40 years (2011–2050) was studied. The future weather data was generated ...

  3. Institutional Arrangements for River Basin Management: A Case Study of Comparison between the United States and China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Gang-yan

    2007-01-01

    This note compares institutional arrangements for water resources management in two river basins, namely, those of the Susquehanna River in the United States and the Yangtze River in China. The Susquehanna River Basin Commission is composed of the US federal government and the three states of New York, Pennsylvania, and Maryland through which the Susquehanna River passes. Under the authority of the Susquehanna River Basin Compact, the Commission deals with water resources problems throughout its vast drainage area. In contrast, the Changjiang(Yangtze River) Water Resources Commission (CWRC) lacks relative effectiveness in mobilizing provincial governments in transboundary water resources management.

  4. Hydrochemical characterization and pollution sources identification of groundwater in Salawusu aquifer system of Ordos Basin, China.

    Science.gov (United States)

    Yang, Qingchun; Wang, Luchen; Ma, Hongyun; Yu, Kun; Martín, Jordi Delgado

    2016-09-01

    Ordos Basin is located in an arid and semi-arid region of northwestern China, which is the most important energy source bases in China. Salawusu Formation (Q3 s) is one of the most important aquifer systems of Ordos Basin, which is adjacent to Jurassic coalfield areas. A large-scale exploitation of Jurassic coal resources over ten years results in series of influences to the coal minerals, such as exposed to the oxidation process and dissolution into the groundwater due to the precipitation infiltration. Therefore, how these processes impact groundwater quality is of great concerns. In this paper, the descriptive statistical method, Piper trilinear diagram, ratios of major ions and canonical correspondence analysis are employed to investigate the hydrochemical evolution, determine the possible sources of pollution processes, and assess the controls on groundwater compositions using the monitored data in 2004 and 2014 (before and after large-scale coal mining). Results showed that long-term exploration of coal resources do not result in serious groundwater pollution. The hydrochemical types changed from HCO3(-)-CO3(2-) facies to SO4(2-)-Cl facies during 10 years. Groundwater hardness, nitrate and sulfate pollution were identified in 2014, which was most likely caused by agricultural activities.

  5. Palynological and paleobotanical investigations of Paleogene sections in the Maoming basin, South China

    Science.gov (United States)

    Aleksandrova, G. N.; Kodrul, T. M.; Jin, J. H.

    2015-05-01

    The complex paleobotanical investigations carried out in the Maoming sedimentary basin (Guangdong Province, South China) yielded first data on the taxonomic composition and ecological properties of two large paleofloras from the Youganwo and Huangniuling formations. The palynomorph assemblages from these formations indicate their middle-late Eocene age (Lutetian-Bartonian and Priabonian for the former and latter, respectively). It is shown that sediments of the Youganwo Formation were deposited in an intermittently swamped lacustrine-fluvial plain, which gave way to a freshwater lake. Vegetation of this period was represented by wet subtropical forests with evergreen Fagaceae, Lauraceae, and Palmae. The Huangniuling flora reflects the biome of seasonal tropical forests developed in a broad fluvial plain and its margins. The Eocene floras of the Maoming Basin are marked by the appearance of several recent plant genera, which is also evident from finds of remains of their reproductive structures. The Eocene flora from low latitudes of South China exhibits a notable share of floral elements from middle and high latitudes of East Asia.

  6. Landscape Changes from 1974 to 1995 in the Upper Minjiang River Basin, China

    Institute of Scientific and Technical Information of China (English)

    HE Xing-Yuan; ZHAO Yong-Hua; HU Yuan-Man; CHANG Yu; ZHOU Qi-Xing

    2006-01-01

    Landscape changes were traced over the 20 years from 1974 to 1995 in the upper Minjiang River basin, one of the most important forest regions in China, based on satellite image interpretation to provide basic data for local decision-making as well as sustainable landscape use and management. Results revealed that landscape from 1974 to 1995 changed at the regional scale as the area of forestland decreased, while cropland, shrubland, economic forest, grassland, and built-up land increased. Landscape changes mainly occurred in forestland, shrubland, grassland, economic forest, and built-up land. Moreover, the changes among forestland, shrubland, and grassland were the largest, influencing the whole characteristics of the changes in the basin. Analysis of the changes between 1974 and 1995 in the study area indicated that landscape heterogeneity and fragmentation increased, whereas landscape connectivity decreased. There were multiple reasons for landscape changes. A principal component analysis (PCA) was used to quantitatively study driving forces of landscape changes. The PCA results showed that economic and population factors were the principal driving forces of landscape changes from 1974 to 1995 in the upper Minjiang River basin, and that PCA was a suitable method for investigating driving forces of landscape changes.

  7. Wind as the primary driver of erosion in the Qaidam Basin, China

    Science.gov (United States)

    Rohrmann, Alexander; Heermance, Richard; Kapp, Paul; Cai, Fulong

    2013-07-01

    Deserts are a major source of loess and may undergo substantial wind-erosion as evidenced by yardang fields, deflation pans, and wind-scoured bedrock landscapes. However, there are few quantitative estimates of bedrock removal by wind abrasion and deflation. Here, we report wind-erosion rates in the western Qaidam Basin in central China based on measurements of cosmogenic 10Be in exhumed Miocene sedimentary bedrock. Sedimentary bedrock erosion rates range from 0.05 to 0.4 mm/yr, although the majority of measurements cluster at 0.125±0.05 mm/yr. These results, combined with previous work, indicate that strong winds, hyper-aridity, exposure of friable Neogene strata, and ongoing rock deformation and uplift in the western Qaidam Basin have created an environment where wind, instead of water, is the dominant agent of erosion and sediment transport. Its geographic location (upwind) combined with volumetric estimates suggest that the Qaidam Basin is a major source (up to 50%) of dust to the Chinese Loess Plateau to the east. The cosmogenically derived wind erosion rates are within the range of erosion rates determined from glacial and fluvial dominated landscapes worldwide, exemplifying the effectiveness of wind to erode and transport significant quantities of bedrock.

  8. Denitrifying Bacteria in Paddy Soils of Taihu Lake Basin,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua-Yong; LI Zhen-Gao; PAN Ying-Hua; LI Liang-Mo

    2004-01-01

    This study attempted to determine the characteristics of the communities, the ecological factors, and the denitrifying enzyme activity for denitrifying bacteria found in the paddy soils of the Taihu Lake Basin, China. Samples of the six main soil types of the basin were taken from paddy fields with different fertilities. The total numbers of bacteria and denitrifying bacteria in the high fertility soils were much more than those in low fertility soils, and the number of denitrifying bacteria accounted for 49% to 80% of the total number of bacteria. The O2 content was an important ecological factor that affected denitrification. Of test the strains isolated from the paddy soils in the Taihu Lake Basin, some (e.g., Pseudomonas spp.)grew well under low oxygen partial pressure, while others (e.g., Bacillus spp.) had no strict predilection with O2 content.Another critical ecological factor was the nitrogen concentration. Three selected denitrifying bacteria grew better in a culture medium with 135 instead of 276 mg L-1 nitrogen. At the same time 67% of the test strains were able to reduce NO-3 to NO-2 and 56% had N2O reductase.

  9. 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.

  10. Sustainability of Water Resources in Arid Ecosystems: A View from Hei River Basin, China (Invited)

    Science.gov (United States)

    Zheng, C.; Cheng, G.; Xiao, H.; Ma, R.

    2009-12-01

    The northwest of China is characterized by an arid climate and fragile ecosystems. With irrigated agriculture, the region is a prolific producer of cotton, wheat, and maize with some of the highest output per acre in the country. The region is also rich in ore deposits, with the reserves of numerous minerals ranked at or near the top in the country. However, the sustainability of irrigated agriculture and economic development in the region is threaten by severe eco-environmental problems resulting from both global changes and human activities, such as desertification, salinization, groundwater depletion, and dust storms. All these problems are a direct consequence of water scarcity. As global warming accelerates and rapid economic growth continues, the water shortage crisis is expected to worsen. To improve the bleak outlook for the health of ecosystem and environment in northwest China, the Chinese government has invested heavily in ecosystem restoration and watershed management in recent years. However, the effectiveness of such measures and actions depends on scientific understanding of the complex interplays among ecological, hydrological and socioeconomic factors. This presentation is intended to provide an overview of a major new research initiative supported by the National Natural Science Foundation of China to study the integration of ecological principles, hydrological processes and socioeconomic considerations toward more sustainable exploitation of surface water and groundwater resources in the Hei River Basin in northwest China. The Hei River Basin is an inland watershed located at the center of the arid region in East Asia, stretching from Qilianshan Mountains in the south to the desert in the north bordering China’s Inner Mongolia Autonomous Region and Mongolia. The total area of Hei River Basin is approximately 130,000 km2. The research initiative builds on existing research infrastructure and ecohydrological data and seeks to reveal complex

  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. Controls on alkylphenol occurrence and distribution in oils from lacustrine rift basins in East China

    Institute of Scientific and Technical Information of China (English)

    ZHOU ShuQing; HUANG HaiPing

    2008-01-01

    Oils from two lacustrine rift basins in east China are thoroughly investigated using geochemical method to understand controls on alkylphenol occurrence and distribution in oils. Oils in the Lujiapu Depression,Kailu Basin are derived from the Cretaceous source rocks,and those in the Dongying Depression,Bohai Bay Basin,from the Tertiary source rocks. All oils are experienced relatively short distance of migration and have similar maturity in each basin. Differences in homologue distributions from different oilfields are most likely caused by organic facies variation of source rocks. The oils in the Lujiapu Depression are characterized by high proportion of C3 alkylphenols (prefixes refer to the number of alkylcarbons joined to the aromatic ring of the phenol molecule) and low proportion of cresols and C2 alkylphenols compared to oils from the Dongying Depression. Alkylphenol isomer distribution is possibly affected by depositional environment especially for C3 alkylphenols. Dysoxic freshwater environment is favorable for the formation of propyl or isopropyl substituted C3 alkylphenols,while highly reducing saline water is more suitable for trimethyl substituted C3 alkylphenols. Variations in alkylphenol concentrations within a petroleum system are controlled mainly by secondary migration processes with alkylphenol concentrations decreasing along migration direction. Interestingly,coupled with geological factors,a subtle change of alkylphenol concentrations can be applied to differentiate carrier systems. When oil migrates through sandy beds,concentrations of total alkylphenols decrease dramatically with migration distance,while such change is less significant when oil migrates vertically along faults. However,most isomer ratios potentially related to migration distance are not as effective as those alkylcarbazoles in migration diagnosis due to complicated affecting factors.

  13. Controls on alkylphenol occurrence and distribution in oils from lacustrine rift basins in East China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Oils from two lacustrine rift basins in east China are thoroughly investigated using geochemical method to understand controls on alkylphenol occurrence and distribution in oils. Oils in the Lujiapu Depression, Kailu Basin are derived from the Cretaceous source rocks, and those in the Dongying De- pression, Bohai Bay Basin, from the Tertiary source rocks. All oils are experienced relatively short distance of migration and have similar maturity in each basin. Differences in homologue distributions from different oilfields are most likely caused by organic facies variation of source rocks. The oils in the Lujiapu Depression are characterized by high proportion of C3 alkylphenols (prefixes refer to the number of alkylcarbons joined to the aromatic ring of the phenol molecule) and low proportion of cre- sols and C2 alkylphenols compared to oils from the Dongying Depression. Alkylphenol isomer distri- bution is possibly affected by depositional environment especially for C3 alkylphenols. Dysoxic fresh- water environment is favorable for the formation of propyl or isopropyl substituted C3 alkylphenols, while highly reducing saline water is more suitable for trimethyl substituted C3 alkylphenols. Variations in alkylphenol concentrations within a petroleum system are controlled mainly by secondary migration processes with alkylphenol concentrations decreasing along migration direction. Interestingly, coupled with geological factors, a subtle change of alkylphenol concentrations can be applied to differentiate carrier systems. When oil migrates through sandy beds, concentrations of total alkylphenols decrease dramatically with migration distance, while such change is less significant when oil migrates vertically along faults. However, most isomer ratios potentially related to migration distance are not as effective as those alkylcarbazoles in migration diagnosis due to complicated affecting factors.

  14. Unravelling the factors influencing flooding over the last 60 years in the Wei River Basin, China

    Science.gov (United States)

    Gai, Lingtong; Baartman, Jantiene E. M.; Mendoza-Carranza, Manuel; Wang, Fei; Ritsema, Coen J.; Geissen, Violette

    2016-04-01

    Flood hazard has become a growing concern in the Wei River Basin in China due to the extensive damage to private and public property under the pressure of extreme meteorological events and human intervention in the river basin. A better understanding of the influence of topographic, climatic and especially anthropogenic factors on hydrological discharge and flooding are important for flood regime and water resources management. This study is aiming at answering the questions why, where, when, and how flooding occurs. While most studies focus on single flood events, we aimed at unravelling a multitude of factors contributing to flooding over a decadal timespan. To be able to do this, we used conditional inference tree analysis, a promising method not often applied in hydrological studies. This method allows to rank all the influencing factors by its contribution to the occurrence of flooding therefore to identify the most important ones and spatially important subcatchments leading to flooding on both yearly and monthly bases in the basin. Dam construction period was identified as the most important factor (why) affecting flooding, followed by the elevation of the river outlet. The subcatchment farthest upstream in the basin (where) contributed the most to the discharge at the downstream floodplain. We then analyzed the impact of the periods of dam construction on the precipitation-discharge relationship using cross-correlation and double mass curves analysis, respectively. The results showed a smaller effect of dam construction on the time lags (when) between precipitation and discharge than on the effect of reducing the quantity of discharge (how).

  15. Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin, northwest China

    Science.gov (United States)

    Wang, Liheng; Dong, Yanhui; Xie, Yueqing; Song, Fan; Wei, Yaqiang; Zhang, Jiangyi

    2016-12-01

    Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na+ and Cl- and between Mg2++ Ca2+ and SO4 2- + HCO3 -, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg2++ Ca2+)-(SO4 2- + HCO3 -) and (Na++ K+)-Cl- with a slope of -0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.

  16. Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin, northwest China

    Science.gov (United States)

    Wang, Liheng; Dong, Yanhui; Xie, Yueqing; Song, Fan; Wei, Yaqiang; Zhang, Jiangyi

    2016-08-01

    Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na+ and Cl- and between Mg2++ Ca2+ and SO4 2- + HCO3 -, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg2++ Ca2+)-(SO4 2- + HCO3 -) and (Na++ K+)-Cl- with a slope of -0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.

  17. Revised conceptualization of the North China Basin groundwater flow system: Groundwater age, heat and flow simulations

    Science.gov (United States)

    Cao, Guoliang; Han, Dongmei; Currell, Matthew J.; Zheng, Chunmiao

    2016-09-01

    Groundwater flow in deep sedimentary basins results from complex evolution processes on geological timescales. Groundwater flow systems conceptualized according to topography and/or groundwater table configuration generally assume a near-equilibrium state with the modern landscape. However, the time to reach such a steady state, and more generally the timescales of groundwater flow system evolution are key considerations for large sedimentary basins. This is true in the North China Basin (NCB), which has been studied for many years due to its importance as a groundwater supply. Despite many years of study, there remain contradictions between the generally accepted conceptual model of regional flow, and environmental tracer data. We seek to reconcile these contractions by conducting simulations of groundwater flow, age and heat transport in a three dimensional model, using an alternative conceptual model, based on geological, thermal, isotope and historical data. We infer flow patterns under modern hydraulic conditions using this new model and present the theoretical maximum groundwater ages under such a flow regime. The model results show that in contrast to previously accepted conceptualizations, most groundwater is discharged in the vicinity of the break-in-slope of topography at the boundary between the piedmont and central plain. Groundwater discharge to the ocean is in contrast small, and in general there are low rates of active flow in the eastern parts of the basin below the central and coastal plain. This conceptualization is more compatible with geochemical and geothermal data than the previous model. Simulated maximum groundwater ages of ∼1 Myrs below the central and coastal plain indicate that residual groundwater may be retained in the deep parts of the basin since being recharged during the last glacial period or earlier. The groundwater flow system has therefore probably not reached a new equilibrium state with modern-day hydraulic conditions. The

  18. Uplifting of the Jiamusi Block in the eastern Central Asian Orogenic Belt, NE China: evidence from basin provenance and geochronology

    Science.gov (United States)

    Liu, Yongjiang; Wen, Quanbo; Han, Guoqing; Li, Wei

    2010-05-01

    The main part of Jiamusi Block, named as Huanan-Uplift, is located in the northeastern Heilongjiang, China. The Huanan-Uplift is surrounded by many relatively small Mesozoic-Cenozoic basins, e.g. Sanjiang Basin, Hulin Basin, Boli Basin, Jixi Basin, Shuangyashan Basin and Shuanghua Basin. However previous research works were mainly focused on stratigraphy and palaeontology of the basins, therefore, the coupling relation between the uplift and the surrounding basins have not been clear. Based on the field investigations, conglomerate provenance studies of the Houshigou Formation in Boli Basin, geochronology of the Huanan-Uplift basement, we have been studied the relationships between Huanan-Uplift and the surrounding basins. The regional stratigraphic correlations indicates that the isolated basins in the area experienced the same evolution during the period of the Chengzihe and the Muling Formations (the Early Cretaceous). The paleogeography reconstructions suggest that the area had been a large-scale basin as a whole during the Early Cretaceous. The Huanan-Uplift did not exist. The paleocurrent directions, sandstone and conglomerate provenance analyses show that the Huanan-Uplift started to be the source area of the surrounding basins during the period of Houshigou Formation (early Late Cretaceous), therefore, it suggests that the Jiamusi Block commenced uplift in the early Late Cretaceous. The granitic gneisses in Huanan-Uplift give 494-415 Ma monazite U-Th-total Pb ages, 262-259 Ma biotite and 246-241 Ma K-feldspar 40Ar/39Ar ages. The cooling rates of 1-2 ℃/Ma from 500-260 Ma and 10-11 ℃/Ma from 260-240 Ma have been calculated based on the ages. This suggests that the Jiamusi Block had a rapid exhumation during late Permian, which should be related to the closure of the Paleo-Asian Ocean between the Siberian and North China continents. It is concluded that during the late Paleozoic the Jiamusi Block was stable with a very slow uplifting. With the closure of

  19. Flash flood hazard mapping: a pilot case study in Xiapu River Basin, China

    Directory of Open Access Journals (Sweden)

    Da-wei Zhang

    2015-07-01

    Full Text Available Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of flash flood hazard mapping. In this study, the headwater catchment of the Xiapu River Basin in central China was selected as a pilot study area for flash flood hazard mapping. A conceptual distributed hydrological model was developed for flood calculation based on the framework of the Xinanjiang model, which is widely used in humid and semi-humid regions in China. The developed model employs the geomorphological unit hydrograph method, which is extremely valuable when simulating the overland flow process in ungauged catchments, as compared with the original Xinanjiang model. The model was tested in the pilot study area, and the results agree with the measured data on the whole. After calibration and validation, the model is shown to be a useful tool for flash flood calculation. A practicable method for flash flood hazard mapping using the calculated peak discharge and digital elevation model data was presented, and three levels of flood hazards were classified. The resulting flash flood hazard maps indicate that the method successfully predicts the spatial distribution of flash flood hazards, and it can meet the current requirements in China.

  20. The Basin Water Resources Management System and Its Innovation in China

    Institute of Scientific and Technical Information of China (English)

    Xun; Pomponio

    2008-01-01

    Water provides the origin of human survival and prosperity,and the basic resource for the maintenance of terrestrial eco-systems,their biodiversity,productivity and ecological services.With China’s recent,rapid growth both in population and economic development,the water shortage has become one of the most constraints on its ecological restoration and socio-economic development,especially in the arid inland regions of northwest China.At first glance,this water shortage in China appears to be a resource crisis.But second,an in-depth analysis reveals that the water shortage crisis arises mainly resulting from the poor water management system and operating mechanism that cannot facilitate fair allocation and efficient utilization of water resources both regionally and nationally and thus is viewed as a crisis of water manage-ment.The solution of China’s water shortage and low-efficient utilization problem will,in particular,require a fundamen-tal and substantial reform or innovation of the existing water management system and operating mechanism.In this paper,we address explicitly the problems existed in the current water management system,explore the basic theory of water re-sources management and provide some insights into the way how to establish a river basin based integrated water re-sources management system in China.

  1. Molecular isotopic characterisation of hydrocarbon biomarkers in Palaeocene-Eocene evaporitic, lacustrine source rocks from the Jianghan Basin, China

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Grice, Kliti; Schouten, S.; Peters, Kenneth E.

    1998-01-01

    Immature organic matter in lacustrine source rocks from the Jianghan Basin, eastern China, was studied for distributions and stable carbon isotopic compositions (13C) of hydrocarbon biomarkers. All of the bitumens contain isorenieratane (13C ca. −17 ) indicating the presence of Chlorobiaceae, and th

  2. 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. 

  3. Division of Gas Accumulation System and Laws Controlling Distribution of Natural Gas in Typical Petroliferous Basins of China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Considering the existing problems of the petroleum system, this paper brings forward the concept of natural gas accumulation system and presents the dividing principles. Then detailed statistics on the accumulation factors of the 32 typical natural gas accumulation systems in China and studies on the laws controlling distribution of gas are collected. The research shows that the petroleum accumulation system is the basic unit controlling petroleum generation, migration and accumulation. Generating intensity, generating amount, accumulating efficiency and migration distance plays an important role in the distribution of natural gas. Through analysis on results of resources evaluation, discovered reserves and residual reserves, potential areas in middle-scaled petroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basins are found out to be the main basins developing and enriching gas accumulation systems.

  4. Response of ESV to Climate Change and Human Activities in the Yanqi Basin, Xinjiang, China

    Science.gov (United States)

    Rusuli, Yusufujiang; Sidik, Halida; Gupur, Adila; Hong, Jiang; Kadir, Rayila

    2016-04-01

    Ecosystem goods and services refer to the dependence of economic wealth and human well-being on natural systems. It is a common knowledge that the changing of structure and function of the ecosystem due to climate change and human activities. It is a priority issue to study on various spatiotemporal scales, the sensitivity of ecosystems to climate change and anthropogenic pressure in inland areas. In an effort to better understand the influence of climate change and human activities on ecosystem services, we evaluated the change in ESV of the Yanqi Basin in Xinjiang, China from 1973 to 2014 employing methods of MK, MK Sneyers, ESV and dynamic degree of LUCC. The Landsat images, digital elevation model (DEM) and metrological data were applied to assessing the ESV and its change. According to the degree of effects of the climate change and human activities, the research area was divided into two parts: the mountain area and the plain oasis area at a contour of 1400 m above sea level. According to type and affect, the land cover was classified as water, wetland, desert, fields, glacier, warm shrub grassland, cold meadow steppe and highland vegetation. We analyzed the relationship between the variation of ESV and precipitation, and evaporation and then quantitatively differentiated the influence of climate change and human activities on ESV. Results show that: (1) distinct change points of precipitation and evaporation in mountain and plain oasis of the Yanqi basin were detected by the MK-Sneyers test. The precipitation increased and the evaporation declined in mountain and plain oasis in the same way. Enlargement of agricultural areas to accommodate an increased population and socio-economic development was detected by conversion matrix of LUCC in oasis area. As a result, the variation of ESV was caused by climate change and human activities jointly; (2) the declining trend of ESV in the mountain area was mainly caused by shrinking of the glacier area; (3) ESV was

  5. Tectonic differences between eastern and western sub-basins of the Qiongdongnan Basin and their dynamics

    Science.gov (United States)

    Liu, Jianbao; Sun, Zhen; Wang, Zhenfeng; Sun, Zhipeng; Zhao, Zhongxian; Wang, Zhangwen; Zhang, Cuimei; Qiu, Ning; Zhang, Jiangyang

    2015-03-01

    The central depression of the Qiongdongnan Basin can be divided into the eastern and western sub-basins by the Lingshui-Songnan paleo-uplift. To the northwest, the orientation of the faults turns from NE, to EW, and later to NW; In the southwest, the orientation of the faults turns from NE, to NNE, and then to NW, making the central depression much wider towards the west. In the eastern sub-basin, the NE-striking faults and the EW-striking faults made up an echelon, making the central depression turn wider towards the east. Fault activity rates indicate that faulting spreads gradually from both the east and west sides to the middle of the basin. Hence, extensional stress in the eastern sub-basin may be related to the South China Sea spreading system, whereas the western sub-basin was more under the effect of the activity of the Red River Fault. The extreme crustal stretching in the eastern sub-basin was probably related to magmatic setting. It seems that there are three periods of magmatic events that occurred in the eastern sub-basin. In the eastern part of the southern depression, the deformed strata indicate that the magma may have intruded into the strata along faults around T60 (23.3 Ma). The second magmatic event occurred earlier than 10.5 Ma, which induced the accelerated subsidence. The final magmatic event commenced later than 10 Ma, which led to today's high heat flow. As for the western sub-basin, the crust thickened southward, and there seemed to be a southeastward lower crustal flow, which happened during continental breakup which was possibly superimposed by a later lower crustal flow induced by the isostatic compensation of massive sedimentation caused by the right lateral slipping of the Red River Fault. Under the huge thick sediment, super pressure developed in the western sub-basin. In summary, the eastern sub-basin was mainly affected by the South China Sea spreading system and a magma setting, whereas the western sub-basin had a closer

  6. Holocene vegetation, environment and anthropogenic influence in the Fuzhou Basin, southeast China

    Science.gov (United States)

    Yue, Yuanfu; Zheng, Zhuo; Rolett, Barry V.; Ma, Ting; Chen, Cong; Huang, Kangyou; Lin, Gongwu; Zhu, Guangqi; Cheddadi, Rachid

    2015-03-01

    A ∼40 m sediment core (FZ4) was collected from the Fuzhou Basin, near the lower reaches of the Min River, in Fujian Province on the southeast coast of China. The sediment and pollen record contributes to our understanding of Holocene paleogeography, including local changes in vegetation and climate in the context of Neolithic cultural developments. The sediment record reveals a fluvial environment in the Fuzhou Basin during the late Pleistocene, and it demonstrates that a change from fluvial to estuarine conditions at ∼9000 cal yr BP resulted from postglacial sea level rise. Evidence of abundant marine diatoms and tidal flat laminations observed in the FZ4 sediments, implies that the Fuzhou Basin was under marine influence between ∼9000 and ∼2000 cal yr BP. After 2000 cal yr BP, a rapid retreat in coastline associated with fluvial aggradation and coastal progradation produced more shallow water for wetlands and initiated formation of the floodplain landscape. The pollen record reveals the presence of a dense subtropical forest between ca. 9000 and 7000 cal yr BP, representing the Holocene thermal maximum, which is linked with rising sea level and marine transgression in the Fuzhou Basin. Between ca. 5500 and 2000 cal yr BP, the thermophilous forest dominated by Castanopsis retreated and coniferous forest expanded, reflecting moderate climatic cooling during this period. Timing of the high frequencies for Pinus and ferns correspond with the mid-late Holocene cooling trend recorded in local mountain peatland and coastal regions of the lower Yangtze and Hanjiang deltas. Anthropogenically induced land cover change was negligible prior to the Tanshishan cultural period, which marks the beginning of Neolithic era sedentary village life on the Fujian coast around 5500 BP. The pollen transition at ca. 3000-1500 cal yr BP, distinguished by rising frequencies of Poaceae and taxa (including Cyperaceae and Artemisia) closely associated with agricultural land cover

  7. Evaluation of Petroleum System in Xihu Depression, East China Sea Shelf Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    According to the theory of petroleum system and the characteristics of petroleum geology, the Xihu depression in the East China Sea shelf basin is divided into four petroleum systems: the Pinghu Formation as source rock and the Huagang Formation as reservoir rock, the Huagang Formation as source rock and reservoir rock, the Paleocene as source rock and the burial-hill as reservoir rock, and the Miocene as source rock and reservoir rock. The system with the Pinghu Formation as source rock and the Huagang Formation as reservoir rock is the most important one in the depression, which has high hydrocarbon generation and accumulation efficiency and is the most important object to hydrocarbon exploration at present.

  8. Marine dinoflagellates from Lower Cretaceous Muling Formation of Jixi Basin,China and their palaeoenvironmental significance

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaoju; HE Chengquan; LI Wenben; PIAO Taiyuan

    2003-01-01

    Newly discovered marine dinoflagellates from the lower-middle parts of the Lower Cretaceous Muling Formation of the Jixi Basin, eastern Heilongjiang Province, China, were identified as Circulodinium cingulatum He et al., C. attadalicum (Cookson et Eisenack) Helby, Palaeoperidinium cretaceum Pocock, Oligosphaeridium totum Brideaux and Sentusidinium sp. Most of these species are distributed in the marine Lower Cretaceous strata of Europe, North America, Africa, Australia and Asia. It demonstrates that a transgression occurred in eastern Heilongjiang Province during the deposition of the Muling Formation, which was previously considered to be a coal-bearing continental stratigraphic unit. The marine dinoflagellates indicated that the Muling Formation is Barremian in age. The Palaeogeographic framework of eastern Heilongjiang Province in Late Mesozoic era should be rebuilt through systematic facies analyses of the marine, paralic and terrestrial deposits.

  9. Arsenic release by indigenous bacteria Bacillus cereus from aquifer sediments at Datong Basin, northern China

    Science.gov (United States)

    Xie, Zuoming; Wang, Yanxin; Duan, Mengyu; Xie, Xianjun; Su, Chunli

    2011-03-01

    Endemic arsenic poisoning due to long-term drinking of high arsenic groundwater has been reported in Datong Basin, northern China. To investigate the effects of microbial activities on arsenic mobilization in contaminated aquifers, Bacillus cereus ( B. cereus) isolated from high arsenic aquifer sediments of the basin was used in our microcosm experiments. The arsenic concentration in the treatment with both bacteria and sodium citrate or glucose had a rapid increase in the first 18 d, and then, it declined. Supplemented with bacteria only, the concentration could increase on the second day. By contrast, the arsenic concentration in the treatment supplemented with sodium citrate or glucose was kept very low. These results indicate that bacterial activities promoted the release of arsenic in the sediments. Bacterial activities also influenced other geochemical parameters of the aqueous phase, such as pH, Eh, and the concentrations of dissolved Fe, Mn, and Al that are important controls on arsenic release. The removal of Fe, Mn, and Al from sediment samples was observed with the presence of B. cereus. The effects of microbial activities on Fe, Mn, and Al release were nearly the same as those on As mobilization. The pH values of the treatments inoculated with bacteria were lower than those without bacteria, still at alkaline levels. With the decrease of Eh values in treatments inoculated with bacteria, the microcosms became more reducing and are thus favorable for arsenic release.

  10. Eco-Environmental Vulnerability Evaluation in the Yellow River Basin,China

    Institute of Scientific and Technical Information of China (English)

    WANG Si-Yuan; LIU Jing-Shi; YANG Cun-Jian

    2008-01-01

    Using remote sensing (RS) data and geographical information system (GIS),eco-environmental vulnerability and its changes were analyzed for the Yellow River Basin,China,The objective of this study was to improve our understanding of eco-environmental changes so that a strategy of sustainable land use could be established.An environmental numerical model was developed using spatial principal component analysis (SPCA) model.The model contains twelve factors that include variables of land use,soil erosion,topography,climate,and vegetation.Using this model,synthetic ecoenvironmental vulnerability index (SEVI) was computed for 1990 and 2000 for the Yellow River Basin.The SEVI was classified into six levels,potential,slight,light,medium,heavy,and very heavy,following the natural breaks classification.The eco-environmental vulnerability distribution and its changes over the ten years from 1990 to 2000 were analyzed and the driving factors of eco-environmental changes were investigated.The results show that the eco-environmental vulnerability in the study area was at medium level,and the eco-environmental quality had been gradually improved on the whole.However,the eco-environmental quality had become worse over the ten years in some regions.In the study area,population growth,vegetation degradation,and governmental policies for eco-environmental protection were found to be the major factors that caused the eco-environmental changes over the ten years.

  11. Expansion of agricultural oasis in the Heihe River Basin of China: Patterns, reasons and policy implications

    Science.gov (United States)

    Song, Wei; Zhang, Ying

    The Heihe River Basin (HRB) is the second largest inland river basin in the arid region of northwestern China. An agricultural oasis is a typical landscape in arid regions providing precious fertile soil, living space and ecological services. The agricultural oasis change has been one of the key issues in sustainable development in recent decades. In this paper, we examined the changes in the agricultural oasis in HRB and analyzed the socio-economic and climatic driving forces behind them. It was found that the agricultural oasis in HRB expanded by 25.11% and 14.82% during the periods of 1986-2000 and 2000-2011, respectively. Most of the newly added agricultural oases in HRB were converted from grassland (40.94%) and unused land (40.22%). The expansion in the agricultural oasis mainly occurred in the middle reaches of HRB, particularly in the counties of Shandan, Minle, Jinta and Jiuquan city. Changes in the rural labor force, annual temperature and precipitation have significant positive effects on agricultural oasis changes, while the ratio of irrigated agricultural oases has significant negative effects on agricultural oasis changes. The agricultural oasis expansion in HRB is the combined effect of human activity and climate change.

  12. Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; YANG Xiaoping; Steve KERSHAW; ZHANG Baomin

    2006-01-01

    Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the shelf of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg2+ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.

  13. Simulation of nitrogen and phosphorus loads in the Dongjiang River basin in South China using SWAT

    Institute of Scientific and Technical Information of China (English)

    Yiping WU; Ji CHEN

    2009-01-01

    Population growth, urbanization, and intensi-fied agriculture have resulted in mobilization of nitrogen and phosphorus, which is the main cause of river water quality deterioration. Environmental regulation has expe-dited the necessity for agricultural producers to design and implement more environmentally suitable practices. Therefore, there is a need to identify critical nutrients and their loss/transport potential. Watershed model can be used to better understand the relationship between land use activities/management and hydrologic processes/water quality changes that occur within a watershed. The objective of the study is to test the performance of the SWAT model and the feasibility of using this model as a simulator of water flow and nitrogen and phosphorus yields over the Dongjiang River basin in South China.Spatial data layers of land slope, soil type, and land use were combined with geographic information system (GIS) to aid in creating model inputs. The observed streamflow and sediment at Boluo station in the Dongjiang River basin were used to calibrate and validate the model. Time series plots and statistical measures were used to verify model predictions. Predicted values generally matched well with the observed values during calibration and validation (R2≥0.6 and Nash-Suttcliffe Efficiency ≥0.5) except for underestimation of sediment peaks and overestimation of sediment valleys at Boluo. This study shows that SWAT is able to predict streamflow, sediment generation, and nutrients transport with satisfactory results.

  14. Paleomagnetic dating of the Cenjiawan Paleolithic site in the Nihewan Basin, northern China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Rock magnetic and magnetostratigraphic investigations on a lacustrine sequence in the Nihewan Basin, northern China, which bears the Cenjiawan Paleolithic site, indicate that the dominant magnetic mineral and remanence carrier contained in the sediments is magnetite. While hematite co-exists with magnetite in some portions of the Cenjiawan sequence, where characteristic remanent magnetizations are carried by both magnetite and hematite. Measurements of anisotropy of magnetic susceptibility confirm that the Cenjiawan sequence has preserved the original sedimentary features and is suitable for magnetostratigraphic study. Paleomagnetic results indicate that the Cenjiawan Paleolithic site is formed just posterior to the Punaruu normal event, which is dated at about 1.1 Ma. Combined with the paleomagnetic results of the Donggutuo, Xiaochangliang and Majuangou sections, it is concluded that early humans were occupying the Nihewan Basin around 1.6, 1.3 and 1.1 Ma. This integrated result is significant to understanding the ability of migration and adaptation to the environment of early humans.

  15. Transition from platemargin to intraplate environment: Geochemistry of basalts in Paleogene Liaohe basin, northeastern China

    Institute of Scientific and Technical Information of China (English)

    WU Changzhi; GU Lianxing; REN Zuowei; ZHANG Zunzhong; CHEN Zhenyan; ZHAO Ming

    2005-01-01

    Paleogene basalts from the Liaohe basin, northeastern China, are dominated by alkaline olivine basalts and olivine basalts. These basalts are generally enriched in high field strength elements (HFSE), depleted in large ion lithophile elements (LILE) and comparable to those of typical ocean island basalts (OIB). Positive anomalies of Ba, Sr and Zr with high Nb/U, U/Pb, Ce/Pb and Zr/Hf ratios imply that materials from an oceanic crust had been added to the mantle sources of the basalts. In addition, the basalts are generally depleted in Sr, Nd and Pb isotopes, indicating that an enriched mantle (EMI) and a depleted mantle (DM) sources were added to the OIB-like resource.Comprehensive research on lithosphere evolution and tectonic setting of the Liaohe basin and surrounding areas suggests that these basalts were derived by variable degrees of partial melting from an upwelling asthenosphere mantle. Materials from an oceanic lithosphere were added to the source in company with Paleogene tectonic transition from platemargin to intraplate environment. Retreating and steepening of the subducting Pacific oceanic plate could be the main cause for the tectonic environment transition.

  16. Arsenic release by indigenous bacteria Bacillus cereus from aquifer sediments at Datong Basin, northern China

    Institute of Scientific and Technical Information of China (English)

    Zuoming XIE; Yanxin WANG; Mengyu DUAN; Xianjun XIE; Chunli SU

    2011-01-01

    Endemic arsenic poisoning due to long-term drinking of high arsenic groundwater has been reported in Datong Basin, northern China. To investigate the effects of microbial activities on arsenic mobilization in contaminated aquifers, Bacillus cereus (B. cereus) isolated from high arsenic aquifer sediments of the basin was used in our microcosm experiments. The arsenic concentration in the treatment with both bacteria and sodium citrate or glucose had a rapid increase in the first 18 d, and then, it declined.Supplemented with bacteria only, the concentration could increase on the second day. By contrast, the arsenic concentration in the treatment supplemented with sodium citrate or glucose was kept very low. These results indicate that bacterial activities promoted the release of arsenic in the sediments. Bacterial activities also influenced other geochemical parameters of the aqueous phase, such as pH,Eh, and the concentrations of dissolved Fe, Mn, and Al that are important controls on arsenic release. The removal of Fe, Mn, and Al from sediment samples was observed with the presence of B. cereus. The effects of microbial activities on Fe, Mn, and Al release were nearly the same as those on As mobilization. The pH values of the treatments inoculated with bacteria were lower than those without bacteria, still at alkaline levels. With the decrease of Eh values in treatments inoculated with bacteria, the microcosms became more reducing and are thus favorable for arsenic release.

  17. Geochemical Characteristics and Origin of Tar Mats from the Yaha Field in Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    张敏; 张俊; 等

    1999-01-01

    Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs associated with Lower Tertiary sandstone reservoirs in the Yaha field of the Tarim Basin,China,by thin-layer chromatography-flame ionization detector(TLC-FID)and Rock-Eval analysis.The relative content of asphaltene in gross composition of tar mat extracts accounts for more than 30%,that in the corresponding oil leg less than 20%.In the geochemical description profile of oil gas reservoirs,drastic changes in asphaltene contents between tar mats and oil legs could be discovered.This in an important marker to determine tar mats.Distribution characteristics of saturated and aromaic hydrocarbons from reservoir core extracts and crude oils in the Yaha oil and gas reservoirs in the Tarim Basin are described systematically in this paper,and the results show there are similarities among n-alkane distribution characteristics,biomarker distribution characteristics and their combined characteristics of saturated hydrocarbons,and the geochemical characteristics of aromatic hydrocarbons for tar mats.oil leg,asphaltic sand and crude oil.These characteristics suggest the hydrocarbons in these samples were originated from the common source rocks.However,the geochemical characteristics of tar mats reveales that the mechanism of formation of tar mats is the precipitation of asphaltene from crude oils in petroleum reservoirs caused by increased dissolved gas in oil legs(gas injection).

  18. Multiple Time Scale Analysis of River Runoff Using Wavelet Transform for Dagujia River Basin, Yantai, China

    Institute of Scientific and Technical Information of China (English)

    LIU Delin; LIU Xianzhao; LI Bicheng; ZHAO Shiwei; LI Xiguo

    2009-01-01

    Based on monOdy river runoff and meteorological data, a method of Morlet wavelet transform was used to analyze the multiple time scale characteristics of river runoffin the Dagnjia River Basin, Yantai City, Shandong Province. The results showed that the total annual river runoff in the Dagujia River Basin decreased significantly from 1966 to 2004, and the rate of decrease was 48×106m3/10yr, which was higher than the mean value of most rivers in China. Multiple time scale characteristics existed, which accounted for different aspects of the changes in annual river runoff, and the major periods of the runoff time series were identified as about 28 years, 14 years and 4 years with decreasing levels of fluctuation. The river runoff evolution process was controlled by changes in precipitation to a certain extent, but it was also greatly influenced by human activities. Also, for different time periods and scales, the impacts of climate changes and human activities on annual river runoff evolution occurred at the same time. Changes in the annual river runoffwere mainly associated with climate change before the 1980s and with human activities after 1981.

  19. Molecular correlation of free oil and inclusion oil of reservoir rocks in the Junggar Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Changchun Pan; Jiamo Fu; Guoying Sheng [Chinese Academy of Sciences, Guangdong (China). State Key Laboratory of Organic Geochemistry; Jianqiang Yang [Research Institute of Exploration and Development, Xinjiang (China)

    2003-03-01

    Free oils and inclusion oils (oil-bearing fluid inclusions) of 12 samples collected from the sandstone reservoir formations in the central, eastern and northern areas of the Junggar Basin, northwest China, were analyzed by GC and GC-MS. Analytical results indicate very similar biomarker distributions within each of the free oils and their associated inclusion oils in the two samples collected, respectively, from the northwestern and eastern border of the Junggar Basin. The free oil and inclusion oil of sample MD1-1, collected from the northwestern border, correlate well with the Permian source rock of the Fencheng Formation, while those of sample DN1-1 from the eastern border correlate with the Permian source rock of the Pingdiquan Formation. In contrast, in the central area, the free and inclusion oils vary significantly in most cases, which suggests variations of sources for oil charges during the filling process. These data, and the correlation between the free and inclusion oils, are consistent with the field and seismic data, which show that in areas where samples MD1-1 and DN1-1 are located, only one available source rock exists, while in the central area, multiple source rocks are present. (author)

  20. Methylotrophic methanogenesis governs the biogenic coal bed methane formation in Eastern Ordos Basin, China.

    Science.gov (United States)

    Guo, Hongguang; Yu, Zhisheng; Liu, Ruyin; Zhang, Hongxun; Zhong, Qiding; Xiong, Zhenghe

    2012-12-01

    To identify themethanogenic pathways present in a deep coal bed methane (CBM) reservoir associated with Eastern Ordos Basin in China, a series of geochemical and microbiological studies was performed using gas and water samples produced from the Liulin CBM reservoir. The composition and stable isotopic ratios of CBM implied a mixed biogenic and thermogenic origin of the methane. Archaeal 16S rRNA gene analysis revealed the dominance of the methylotrophic methanogen Methanolobus in the water produced. The high potential of methane production by methylotrophic methanogens was found in the enrichments using the water samples amended with methanol and incubated at 25 and 35 °C. Methylotrophic methanogens were the dominant archaea in both enrichments as shown by polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE). Bacterial 16S rRNA gene analysis revealed that fermentative, sulfate-reducing, and nitrate-reducing bacteria inhabiting the water produced were a factor in coal biodegradation to fuel methanogens. These results suggested that past and ongoing biodegradation of coal by methylotrophic methanogens and syntrophic bacteria, as well as thermogenic CBM production, contributed to the Liulin CBM reserves associated with the Eastern Ordos Basin.

  1. Effects of land use patterns on soil aggregate stability in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    Zhen Zhang; Chaofu Wei; Deti Xie; Ming Gao; Xibai Zeng

    2008-01-01

    Soil aggregate stability as a key indicator of soil structure, is a product of interactions between soil environment, management practices, and land use patterns. The objective of this study was to analyze the impact of various land use patterns on soil aggregate stability in Sichuan Basin of southwestern China. The dry- and water-stable aggregate size distributions were determined by manual dry sieving procedure and Yoder's wet sieving procedure, respectively, while microaggregates and its mechanical and chemical stabilities by Kachisky's method, oscillator method, and citrate-dithionate (C-D) reagent method, separately. The results indicated that fractal dimension and surface fractal dimension were useful indicators to reflect soil aggregate distribution. Land use patterns have an obvious influence on soil aggregate stability. In the study area, water stability, mechanical stability, and chemical stability followed the sequence, Barren landforestlandorchardcropland, and the original stability and collapse velocity were sensitive to soil properties and soil structure. The difference of aggregate stability under different land use patterns is mainly due to the intensity of human disturbance and cultivation. Improper land use patterns will lead to breakdown of unstable aggregates, producing finer and more-easily transportable particles and microaggregates. In the future, inappropriate cultivation and land use patterns should be changed to protect soil structure, to improve soil aggregate stability and soil fertility in Sichuan Basin.

  2. Preliminary Simulations of CO2 Transport in the Dolostone Formations in the Ordos Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Y; Wolery, T; Carroll, S

    2009-04-30

    This report summarizes preliminary 2-D reactive-transport simulations on the injection, storage and transport of supercritical CO{sub 2} in dolostone formations in the Ordos Basin in China. The purpose of the simulations was to evaluate the role that basin heterogeneity, permeability, CO{sub 2} flux, and geochemical reactions between the carbonate geology and the CO{sub 2} equilibrated brines have on the evolution of porosity and permeability in the storage reservoir. The 2-D simulation of CO{sub 2} injection at 10{sup 3} ton/year corresponds to CO{sub 2} injection at a rate of 3 x 10{sup 5} ton/year in a 3-D, low permeable rock. An average permeability of 10 md was used in the simulation and reflects the upper range of permeability reported for the Ordos Basin Majiagou Group. Transport and distribution of CO{sub 2} between in the gas, aqueous, and solid phases were followed during a 10-year injection phase and a 10-year post injection phase. Our results show that CO{sub 2} flux and the spatial distribution of reservoir permeability will dictate the transport of CO{sub 2} in the injection and post injection phases. The injection rate of supercritical CO{sub 2} into low permeable reservoirs may need to be adjusted to avoid over pressure and mechanical damage to the reservoir. Although it should be noted that 3-D simulations are needed to more accurately model pressure build-up in the injection phase. There is negligible change in porosity and permeability due to carbonate mineral dissolution or anhydrite precipitation because a very small amount of carbonate dissolution is required to reach equilibrium with respect these phases. Injected CO{sub 2} is stored largely in supercritical and dissolved phases. During the injection phase, CO{sub 2} is transport driven by pressure build up and CO{sub 2} buoyancy.

  3. Modeling of soil erosion and sediment transport in the East River Basin in southern China.

    Science.gov (United States)

    Wu, Yiping; Chen, Ji

    2012-12-15

    Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

  4. Changes in Remotely Sensed Vegetation Growth Trend in the Heihe Basin of Arid Northwestern China.

    Directory of Open Access Journals (Sweden)

    Wenchao Sun

    Full Text Available The Heihe River Basin (HRB is the second largest inland river basin in China, characterized by high diversity in geomorphology and irrigated agriculture in middle reaches. To improve the knowledge about the relationship between biotic and hydrological processes, this study used Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index (NDVI data (1982-2006 to analyze spatiotemporal variations in vegetation growth by using the Mann-Kendall test together with Sen's slope estimator. The results indicate that 10.1% and 1.6% of basin area exhibit statistically significant (p < 0.05 upward and downward trends, and maximum magnitude is 0.066/10a and 0.026/10a, respectively. More specifically, an increasing trend was observed in the Qilian Mountains and Hexi Corridor and a decreasing trend detected in the transitional region between them. Increases in precipitation and temperature may be one possible reason for the changes of vegetation growth in the Qilian Mountains. And decreasing trend in transitional region may be driven by the changes in precipitation. Increases of irrigation contribute to the upward trend of NDVI for cropland in the Hexi Corridor, reflecting that agricultural development becomes more intensive. Our study demonstrates the complexity of the response of vegetation growth in the HRB to climate change and anthropogenic activities and correspondingly adopting mechanistic ecological models capable of describing both factors is favorable for reasonable predictions of future vegetation growth. It is also indicated that improving irrigation water use efficiency is one practical strategy to balance water demand between human and natural ecosystems in the HRB.

  5. Regime Shift Identification of Runoff and Sediment Loads in the Yellow River Basin, China

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2014-10-01

    Full Text Available Runoff and sediment loads have exhibited significant changes over the past six decades in the Yellow River Basin, China. The current study evaluates the changing trends and regime shifts in runoff and sediment loads at both the annual and monthly time scales. The associated spatial and temporal variations are analyzed by a sequential t-test analysis of the regime shifts (STARS approach and the “breaks for additive seasonal and trend” (BFAST model using hydrological data at eight stations from the 1950s to 2011. Both runoff and sediment loads exhibit significant declines (p < 0.05, except in the upper reaches of the river near the Tangnaihai station. The regime shifts detected by the STARS approach are not completely consistent with the results from the BFAST method. In most cases, the regime shifts occurred in 1969 and 1986, due to the construction of large reservoirs. Climate change and other human activities, such as large-scale soil and water conservation measures, can result in abrupt changes in hydrological series at some stations. The trapping effects of reservoirs not only cause regime shifts of runoff and sediment loads, but also adjust their inter-annual and seasonal distributions. Various soil and water conservation measures are responsible for the significant reduction in runoff and sediment loads in the mid-lower reaches of the Yellow River Basin. In addition, water withdrawals from both river runoff and ground water play a critical role in the changing trends in runoff and indirectly alter the sediment loads. The findings provide a good reference for the effective promotion of climate change adaptation, water resources planning and river basin management.

  6. Temporal clustering of floods and impacts of climate indices in the Tarim River basin, China

    Science.gov (United States)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Chen, Yongqin David; Shi, Peijun

    2016-12-01

    The occurrence rates of floods in Tarim River basin, the largest arid basin in China, were estimated using the Peak-over-Threshold (POT) technique. The intra-annual, seasonal and inter-annual clustering of floods was then analyzed using the Cox regression model, month frequency method and dispersion index, respectively. Possible impacts of climate indices on the occurrence rates were also investigated. Both NAO and AO are selected as significant covariates to occurrence rates of floods in Tarim River basin by Cox regression model, suggesting occurrence of flood events is not independent, but exhibits temporal clustering in intra-annual scale. On the basis of the results of the station and region-wide modeling by Cox regression model, we suggest using a model in which the rate of occurrence depends on monthly averaged NAO or AO. The Cox regression model not only can be used to assess the time-varying rate of flood occurrence, but also has the capability to forecast the predictors. Flood occurrence time and probability of exceedance are changing with climate index from negative to positive on both station and region scale. In addition, seasonal clustering of station-based floods and regional observed floods are also identified with mainly concentrating from June to August. Meanwhile, dispersion index is used to evaluate the inter-annual clustering of annual number of flood occurrences both on station and region. We found that inter-annual clustering of regional floods is more evident than that of station-based floods, indicating that regional observed flood records are generally over-dispersed with a tendency for flood events to cluster in time.

  7. Paleogene and Early Neogene Lacustrine Reefs in the Western Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jianhua; WEN Zhifeng; GUO Zeqing; WANG Haiqiao; GAO Jianbo

    2004-01-01

    Typical reefs in the Paleogene and early Neogene strata of the Qaidam Basin, Tibetan Plateau, China, reveal their internal structures and sedimentation environments and consist mainly of algal reef, stromatolite reef and thrombolite reef with distinct reef structures, fore-reef, back-reef and reef-plateau. The fore-reef is characterized by a combination of pinnacle reef, thrombolite and algal reef. The back reef is composed of stromatolite reef and algal reef. The pinnacle reefs (micro-atoll), most of which are several tens of centimeters in diameter (whereas some exceptionally big ones are over 200 cm in diameter), and several tens of centimeter to 2 m in height, are situated on the far front-edge of the reef; the pinnacle reef is also often of recumbent form with a gravel-filled circular hole in the center. The algal reef is in the form of dome and irregular beds, and filled with algal detritus, ostracodes, spirorbis fossils, ooid and terrigenous debris, and worm traces;cavities and scour marks are often developed. The algal reef is gray commonly when fresh and weathers to a brown color.The lacustrine thrombolite in the Qaidam Basin is light gray or deep gray when fresh, white-gray or brown when weathered, dense and homogeneous with abundant pores filled by oil and bitumen. Observed under the microscope, the thrombolite consists mainly of brown or brown-black clots with a little algal debris, ooid, pellet, ostracodes, spirorbis fossils and terrigenous debris, in some cases, terrigenous debris, even gravel, is abundant. Many features of the thrombolite suggest that it is formed in a high-energy environment. The stromatolite reefs developed on the lacustrine algal reef in the Qaldam Basin are very complex whether in shape or in internal structure. The simplest ones form laminated layers and the most complex ones have intensely branching structures. The size is also variable.

  8. Formation mechanism and model for sand lens reservoirs in the Jiyang Sub-basin, East China

    Institute of Scientific and Technical Information of China (English)

    LI; Pilong; PANG; Xiongqi; CHEN; Dongxia; ZHANG; Shanwen

    2004-01-01

    The Bohai Bay basin comprises some very important and well documented subtle traps known in China, which have been the major exploration focus and have become a major petroleum play since the 1990s. However, recent exploration showed that the oil-bearing properties of some sand lens reservoirs may vary significantly and the accumulation mechanisms for these lithological subtle traps are not well understood. Based on statistical analysis of oil-bearing properties for 123 sand lens reservoirs in the Jiyang Sub-basin and combined with detailed anatomy of typical sand lens reservoirs and NMR experiments, it has been shown that the structural and sedimentary factors, hydrocarbon generation and expulsion conditions of the surrounding source rocks, as well as the petrophysical properties of sand lens reservoirs are the main controlling factors for the formation of sand lens reservoirs. The formation of a sand lens reservoir depends on the interaction between the hydrocarbon accumulation driving force and the resistance force. The driving force is made up of the differential capillary pressure between sandstones and sources rocks and the hydrocarbon diffusion force, and as well as the hydrocarbon expansion force. The resistance force is the friction resistance force for hydrocarbons and water to move through the pore throats of the sand lens. The sedimentary environment, source rock condition and sand reservoir properties can change from unfavorable to favorable depending on the combination of these factors. When these three factors all reach certain thresholds, the sand lens reservoirs may begin to be filled by hydrocarbons. When all of these conditions become favorable for the formation of sand lens reservoirs, the reservoir would have high oil saturation. This approach has been applied to evaluating the potential of petroleum accumulation in the sand lens reservoirs in the third member of the Neogene Shahejie Formation in the Jiyang Sub-basin.

  9. Structure and kinematic analysis of the deepwater area of the Qiongdongnan Basin through a seismic interpretation and analogue modeling experiments

    Institute of Scientific and Technical Information of China (English)

    SUN Zhen; WANG Zhenfeng; SUN Zhipeng; WANG Zhangwen; ZHANG Wei; HE Lijuan

    2015-01-01

    Located at the northwest continental slope of the South China Sea, the Qiongdongnan Basin bears valley-shaped bathymetry deepening toward east. It is separated from the Yinggehai Basin through NW-trending Indo-China-Red River shear zone, and connected with NW subsea basin through the Xisha Trough. Along with the rapid progress of the deepwater exploration, large amounts of high resolution geophysical and geological data were accumulated. Scientific researches about deepwater basins kept revealing brand new tectonic and sedimentary discoveries. In order to summarize the structural features and main controlling factors of the deepwater Qiongdongnan Basin, a series of researches on basin architecture, fault activities, tectonic deformation and evolution were carried out. In reference to analogue modeling experiments, a tectonic situation and a basin formation mechanism were discussed. The researches indicate that:the northern boundary of the Qiongdongnan Basin is strongly controlled by No. 2 fault. The overlapping control of two stress fields from the east and the west made the central depression zone extremely thinned. Combined with the changed stress field, the segmentation of a preexisting weakness zone made the sags in the east experiencing different rifting histories from the west ones. The NE-trending west segment of the Qiongdongnan Basin experienced strong rifting during Eocene, while the roughly EW-trending sags in the east segment show strong rifting during late Eocene and early Oligocene. Local structures such as NW-trending basal fault and inherited uplifts controlled the lateral segmentation. So first order factors such as regional stress field and preexisting weakness zone controlled the basin zonation, while the second order factors determined the segmentation from east to west.

  10. 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

  11. 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.

  12. Evaluating Impacts of Industrial Transformation on Water Consumption in the Heihe River Basin of Northwest China

    Directory of Open Access Journals (Sweden)

    Feng Wu

    2014-11-01

    Full Text Available Growing water scarcity is one of the central challenges for sustainability in China, given its burgeoning industry and huge population, especially in the arid and semi-arid inland river basin where precipitation is very limited. Industrial transformation is an important engine of economic growth, which is required to be implemented by governments at all levels in China. Economic models have generally been applied to evaluate the effects of economic policy change (e.g., industrial transformation or adjustment of price on the allocation of production factors. The computable general equilibrium (CGE model is an effective tool to reallocate the primary factors across sectors for different industrial transformation scenarios. In this research, we first briefly introduced the principles and structure of the CGE model, which embeds water resources as a primary factor of production. Then we chose Zhangye as an example to evaluate the impacts of industrial transformation on water consumption under three designed scenarios with the water-embedded CGE model. Simulation results showed that there will be considerable water saving benefit from industrial transformation when the output value of secondary industry and tertiary industry increases and the contribution of the planting sector to the total output value decreases. Finally, we put forward a scheme that can improve water utilization efficiency in policy options.

  13. An evaluation of the effect of future climate on runoff in the Dongjiang River basin, South China

    Science.gov (United States)

    Lin, K.; Zhai, W.; Huang, S.; Liu, Z.

    2015-05-01

    The impact of future climate change on the runoff for the Dongjiang River basin, South China, has been investigated with the Soil and Water Assessment Tool (SWAT). First, the SWAT model was applied in the three sub-basins of the Dongjiang River basin, and calibrated for the period of 1970-1975, and validated for the period of 1976-1985. Then the hydrological response under climate change and land use scenario in the next 40 years (2011-2050) was studied. The future weather data was generated by using the weather generators of SWAT, based on the trend of the observed data series (1966-2005). The results showed that under the future climate change and LUCC scenario, the annual runoff of the three sub-basins all decreased. Its impacts on annual runoff were -6.87%, -6.54%, and -18.16% for the Shuntian, Lantang, and Yuecheng sub-basins respectively, compared with the baseline period 1966-2005. The results of this study could be a reference for regional water resources management since Dongjiang River provides crucial water supplies to Guangdong Province and the District of Hong Kong in China.

  14. Distribution characteristics and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the Liao River drainage basin, northeast China.

    Science.gov (United States)

    Hu, Jian; Liu, Congqiang; Zhang, Guoping; Zhang, Yanlin; Li, Siliang; Zhao, Zhiqi; Liu, Baojian; Guo, Qinjun

    2016-04-01

    The Liao River drainage basin, which is one of China's seven major rivers basins, is located in northeast China. This region is characterized by important industrial bases including steel factories and oil and chemical plants, all of which have the potential to contribute pollutants to the drainage basin. In this study, 16 polycyclic aromatic hydrocarbons (PAHs) in water and suspended particulate matter (SPM) in the major rivers of the Liao River drainage basin were identified and quantified by gas chromatography mass spectrometry (GC/MS). The total PAH concentrations ranged from 0.4 to 76.5 μg/g (dry weight) in SPM and 32.6 to 108 ng/L in surface water, respectively. Low-ring PAHs (including two- and three-ring PAHs) were dominant in all PAH samples, and the level of low-ring PAHs in surface water was higher than that in SPM. The proportion of two-ring PAHs was the highest, accounting for an average of 68.2 % of the total PAHs in surface water, while the level of three-ring PAHs was the highest in SPM, with an average of 66.3 %. When compared with other river systems, the concentrations of PAHs in the Liao River drainage basin were lower. Identification of the emission sources based on diagnostic ratios suggested petroleum and fossil fuel combustion were important contribution to PAHs in the study area.

  15. Dual influence of the rejuvenation of Southern Tianshan and Western Kunlun orogen on the Cenozoic structure deformation of Tarim Basin, northwestern China: A superposition deformation model from Bachu Uplift

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on new high-resolution seismic profiles and existing structural and sedimentary results, a superposition deformation model for Cenozoic Bachu Uplift of northwestern Tarim Basin, northwestern China is proposed. The model presents the idea that the Bachu Uplift suffered structure superposition deformation under the dual influences of the Cenozoic uplifting of Southern Tianshan and Western Kunlun orogen, northwestern China. In the end of the Eocene (early Himalayan movement),Bachu Uplift started to be formed with the uplifting of Western Kunlun, and extended NNW into the interior of Kalpin Uplift. In the end of the Miocene (middle Himalayan movement), Bachu Uplift suffered not only the NNW structure deformation caused by the Western Kunlun uplifting, but also the NE structure deformation caused by the Southern Tianshan uplifting, and the thrust front fault of Kalpin thrust system related to the Southern Tianshan orogen intrudes southeastward into the hinterland of Bachu Uplift and extends NNE from well Pil to Xiaohaizi reservoir and Gudongshan mountain, which resulted in the strata folded and denuded strongly. In the end of the Pliocene (late Himalayan movement), the impact of Southern Tianshan orogen decreased because of the stress released with the breakthrough upward of Kalpin fault extending NE, and Bachu Uplift suffered mainly the structure deformation extending NW-NNW caused by the uplifting of Western Kunlun orogen.

  16. 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.

  17. 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

  18. Models for Initial Allocation of Emission Permits in a River Basin During Industrial Development: A Case Study of Huaihe River Basin,China

    Institute of Scientific and Technical Information of China (English)

    Yu Shutong; Huang Xianjin; Cheng Xushui; Wan Yi; Ma Tianqi

    2010-01-01

    At present,water pollutant emission trading plays an increasingly important role in pollution control in many foreign countries,and its pilot studies and demonstration have also been started in China.In order to solve the problem of initial allocation of emission permits: premise and basis of emission trading in a river basin,basic principles on initial allocation of actual emission permits in China are put forward.And it is thought that local development stage of industry should be taken into full account for initial allocation model of emission permits.There are five different allocation models in different development stages of industry,including models like distribution according to needs,improved same-rate reduction,performance,integration and environmental capacity,etc.The initial allocation of emission permits in various basins should choose a suitable model in accordance with their respective development stages.It is suggested in this article that integrated allocation model should be a main choice for current development stage of industry in China.

  19. Optimization of wetland restoration siting and zoning in flood retention areas of river basins in China: A case study in Mengwa, Huaihe River Basin

    Science.gov (United States)

    Zhang, Xiaolei; Song, Yuqin

    2014-11-01

    Wetland restoration in floodplains is an ecological solution that can address basin-wide flooding issues and minimize flooding and damages to riverine and downstream areas. High population densities, large economic outputs, and heavy reliance on water resources make flood retention and management pressing issues in China. To balance flood control and sustainable development economically, socially, and politically, flood retention areas have been established to increase watershed flood storage capacities and enhance the public welfare for the populace living in the areas. However, conflicts between flood storage functions and human habitation appear irreconcilable. We developed a site-specific methodology for identifying potential sites and functional zones for wetland restoration in a flood retention area in middle and eastern China, optimizing the spatial distribution and functional zones to maximize flood control and human and regional development. This methodology was applied to Mengwa, one of 21 flood retention areas in China's Huaihe River Basin, using nine scenarios that reflected different flood, climatic, and hydraulic conditions. The results demonstrated improved flood retention and ecological functions, as well as increased economic benefits.

  20. 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

  1. 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.

  2. A detrital record of continent-continent collision in the Early-Middle Jurassic foreland sequence in the northern Yangtze foreland basin, South China

    Science.gov (United States)

    Qian, Tao; Liu, Shaofeng; Wang, Zongxiu; Li, Wangpeng; Chen, Xinlu

    2016-12-01

    The Mesozoic northern Yangtze foreland basin system was formed by continental collision between the North China and South China plates along the Mianlue suture. Synorogenic stratigraphic sequences of Late Triassic to Early-Middle Jurassic age were developed in the northern Yangtze foreland basin. The upper Middle Jurassic Shaximiao Formation consists mainly of thick-bedded terrestrial successions that serve as the main body of the basin-filling sequences, suggesting intense tectonism in the peripheral orogeny of the foreland basin. Laser-ICP-MS U-Pb analysis of 254 detrital zircon grains from sandstone samples and several published Lower-Middle Jurassic samples, detrital compositions, petrofacies, and paleocurrent reconstructions in the northern Yangtze foreland basin indicate that discrete source areas included the Qinling-Dabieshan ranges and the Mianlue suture zone to the north, and the South China plate to the south. The stratigraphic succession and sediment provenance of the foreland basin imply that the early Mianlue oceanic basin, magmatic arc, and nonmarine molasse foreland basin during the period of deposition were modified or buried by the subsequent continent-continent collision between the North China-Qinling-Dabieshan plate and the Yangtze plate during the Jurassic, which followed the oblique amalgamation between these plates during the Middle-Late Triassic.

  3. Using integrated multivariate statistics to assess the hydrochemistry of surface water quality, Lake Taihu basin, China

    Directory of Open Access Journals (Sweden)

    Xiangyu Mu

    2014-09-01

    Full Text Available Natural factors and anthropogenic activities both contribute dissolved chemical loads to  lakes and streams.  Mineral solubility,  geomorphology of the drainage basin, source strengths and climate all contribute to concentrations and their variability. Urbanization and agriculture waste-water particularly lead to aquatic environmental degradation. Major contaminant sources and controls on water quality can be asssessed by analyzing the variability in proportions of major and minor solutes in water coupled to mutivariate statistical methods.   The demand for freshwater needed for increasing crop production puulation and industrialization occurs almost everywhere in in China and these conflicting needs have led to widespread water contamination. Because of heavy nutrient loadings from all of these sources, Lake Taihu (eastern China notably suffers periodic hyper-eutrophication and drinking water deterioration, which has led to shortages of freshwater for the City of Wuxi and other nearby cities. This lake, the third largest freshwater body in China, has historically beeen considered a cultural treasure of China, and has supported long-term fisheries. The is increasing pressure to remediate the present contamination which compromises both aquiculture and the prior economic base centered on tourism.  However, remediation cannot be effectively done without first characterizing the broad nature of the non-point source pollution. To this end, we investigated the hydrochemical setting of Lake Taihu to determine how different land use types influence the variability of surface water chemistry in different water sources to the lake. We found that waters broadly show wide variability ranging from  calcium-magnesium-bicarbonate hydrochemical facies type to mixed sodium-sulfate-chloride type. Principal components analysis produced three principal components that explained 78% of the variance in the water quality and reflect three major types of water

  4. Seasonal variation in dust events and the causes of the variation in the Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.

  5. Wet and dry nitrogen deposition in the central Sichuan Basin of China

    Science.gov (United States)

    Kuang, Fuhong; Liu, Xuejun; Zhu, Bo; Shen, Jianlin; Pan, Yuepeng; Su, Minmin; Goulding, Keith

    2016-10-01

    Reactive nitrogen (Nr) plays a key role in the atmospheric environment and its deposition has induced large negative impacts on ecosystem health and services. Five-year continuous in-situ monitoring of N deposition, including wet (total nitrogen (WTN), total dissolved nitrogen (WTDN), dissolved organic nitrogen (WDON), ammonium nitrogen (WAN) and nitrate nitrogen (WNN)) and dry (DNH3, DHNO3, DpNH4+, DpNO3- and DNO2) deposition, had been conducted since August 2008 to December 2013 (wet) and May 2011 to December 2013 (dry) in Yan-ting, China, a typical agricultural area in the central Sichuan Basin. Mean annual total N deposition from 2011 to 2013 was 30.8 kg N ha-1 yr-1, and speculated that of 2009 and 2010 was averaged 28.2 kg N ha-1 yr-1, respectively. Wet and dry N deposition accounted for 76.3% and 23.7% of annual N deposition, respectively. Reduced N (WAN, DNH3 and DpNH4+) was 1.7 times of oxidized N (WNN, DHNO3, DNO2 and DpNO3-) which accounted for 50.9% and 30.3% of TN, respectively. Maximum loadings of all N forms of wet deposition, gaseous NH3, HNO3 and particulate NH4+ in dry deposition occurred in summer and minimum loadings in winter. Whether monthly, seasonal or annual averaged, dissolved N accounted for more than 70% of the total. N deposition in the central Sichuan Basin increased during the sampling period, especially that of ammonium compounds, and has become a serious threat to local aquatic ecosystems, the surrounding forest and other natural or semi-natural ecosystems in the upper reaches of the Yangtze River.

  6. Modeling Nutrient Release in the Tai Lake Basin of China: Source Identification and Policy Implications

    Science.gov (United States)

    Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

    2013-03-01

    Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a-1 and 5254.4 tons P a-1, and annual area-specific nutrient loads were 1.94 tons N km-2 and 0.31 tons P km-2. Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

  7. Uncertainty evaluation of copula analysis of hydrological droughts in the East River basin, China

    Science.gov (United States)

    Zhang, Qiang; Xiao, Mingzhong; Singh, Vijay P.

    2015-06-01

    The joint probability behaviors of extreme hydro-meteorological events, such as droughts, have been receiving increasing attentions in recent years. Since extreme hydro-meteorological events are reflected by more than one variable, such as duration and intensity, copula functions have been widely applied. However, uncertainties of copula-based analysis of hydrological droughts as a result of selection of marginal distribution and copulas have not yet received significant concerns. The aim of this study is to evaluate such uncertainties based on Bayesian approach. The method is used to analyze hydrological drought in the East River basin (China), which is the principal supplier of water resources for megacities in the Pearl River Delta and also for Hong Kong. The results indicate that the credible intervals of most likely design drought events with a return period of 20 years in terms of drought severity and duration are considerably large at all stations in the East River basin, covering the drought event curves at return periods of 10 and 50 years. Also the influences of heavy-tailed marginal distribution on the uncertainty evaluation of joint distribution have been investigated. Results show that the stronger the heavy-tailed marginal distribution, the greater the uncertainty of the joint distribution, especially for the extreme event. Results of this study provide a technical reference for uncertainty evaluation in copula-based analysis of drought events at regional and global scales. The large credible interval of drought severity and duration greatly challenges measures of mitigation of drought hazards and water resource management.

  8. 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.

  9. Paleotopographic controls on facies development in various types of braid-delta depositional systems in lacustrine basins in China

    Directory of Open Access Journals (Sweden)

    Dong Feng

    2015-07-01

    Full Text Available Braid-delta depositional systems are widely developed in most continental basins in China. Research indicates that, for different types of braid delta, the facies sequence and association, which are critical to the prediction of the distribution of reservoirs, differ greatly. This study illustrates the differences in braid-delta depositional systems in terms of sedimentary characteristics, associated systems and reservoir distributions using three typical paleodeltas in western China: the Zhenbei delta of the upper Triassic Yanchang Formation in the Ordos Basin, the Yuanba delta of the upper Triassic Xujiahe Formation in the Sichuan Basin and the Jimsar delta of the upper Permian Wutonggou Formation in the Junggar Basin. A stratigraphic framework was established using seismic data, logs and cores by choosing stable mud sections as regional correlation markers and, topographies of these deltas were reconstructed based on the decompaction and paleobathymetric corrections. Based on both the paleotopography of these deltas and the differences of their sedimentary facies, these braided deltas can be classified into two systems: steep-gradient braid-delta-turbidite system and low-gradient braid-delta-lacustrine system. Moreover, the low-gradient braid-delta-lacustrine system can be further divided into interfingered and sharp contact sub-types according to the contact relation between the delta sands and lacustrine muds. This study shows that the paleotopography of basin margins strongly controls the accommodation as braid deltas prograde into lacustrine basins and, influences the location of the shoreline in response to changes in the lake level. Furthermore, paleotopography plays a significant role in facies and reservoir distribution which is important for petroleum exploration and development.

  10. Incorporating Groundwater Dynamics and Surface/Subsurface Runoff Mechanisms in Regional Climate Modeling over River Basins in China

    Institute of Scientific and Technical Information of China (English)

    QIN Peihua; XIE Zhenghui; YUAN Xing

    2013-01-01

    To improve the capability of numerical modeling of climate-groundwater interactions,a groundwater component and new surface/subsurface runoff schemes were incorporated into the regional climate model RegCM3,renamed RegCM3_Hydro.20-year simulations from both models were used to investigate the effects of groundwater dynamics and surface/subsurface runoff parameterizations on regional climate over seven river basins in China.A comparison of results shows that RegCM3_Hydro reduced the positive biases of annual and summer (June,July,August) precipitation over six river basins,while it slightly increased the bias over the Huaihe River Basin in eastern China.RegCM3_Hydro also reduced the cold bias of surface air temperature from RegCM3 across years,especially for the Haihe and the Huaihe river basins,with significant bias reductions of 0.80℃ and 0.88℃,respectively.The spatial distribution and seasonal variations of water table depth were also well captured.With the new surface and subsurface runoff schemes,RegCM3_Hydro increased annual surface runoff by 0.11-0.62 mm d-1 over the seven basins.Though previous studies found that incorporating a groundwater component tends to increase soil moisture due to the consideration of upward groundwater recharge,our present work shows that the modified runoff schemes cause less infiltration,which outweigh the recharge from groundwater and result in drier soil,and consequently cause less latent heat and more sensible heat over most of the basins.

  11. Coal petrology and genesis of Jurassic coal in the Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Weihua Ao

    2012-01-01

    Full Text Available Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal’s petrologic characteristics and its maceral distribution to determine the maceral’s contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin’s unique depositional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petrographic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos’ coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good

  12. Drought monitoring based on TIGGE and distributed hydrological model in Huaihe River Basin, China.

    Science.gov (United States)

    Zhao, Junfang; Xu, Jingwen; Xie, Xingmei; Lu, Houquan

    2016-05-15

    Drought assessment is important for developing measures to reduce agricultural vulnerability and thereby secure the livelihoods of those who depend on agriculture. This study uses four global ensemble weather prediction systems: the China Meteorological Administration (CMA), the European Centre for Medium-Range Weather Forecasts (ECMWF), the UK Met Office (UKMO), and the US National Centres for Environmental Prediction (NCEP) in the THORPEX (The Observing System Research and Predictability Experiment) Interactive Grand Global Ensemble (TIGGE) archive from 2006 to 2010. Based on results from the XXT (the first X denotes Xinanjiang, the second X denotes hybrid, and the T denotes TOPMODEL) distributed hydrological model, as well as soil moisture observations and digital elevation model (DEM) data, synthesized drought grades were established in the Huaihe River Basin of China. To filter out the impact of short-term fluctuations on observed soil moisture, a 30-day moving average was calculated. Use of the moving average significantly improves the correlation between observed soil moisture and simulated soil water deficit depth. Finally, a linear regression model describing the relationship between observed soil moisture and simulated soil water deficit depth was constructed. The deterministic regression coefficient was 0.5872, the correlation coefficient was 0.77, and the regression coefficient was -154.23. The trends in drought grades calculated using soil moisture and soil water deficit depth were found to be the same, and the grades agreed to within one level. Our findings highlight the importance of synthesizing drought grading when assessing drought using different soil moisture indicators in order to obtain a more comprehensive forecast of drought conditions.

  13. Urbanization dramatically altered the water balances of a paddy field dominated basin in Southern China

    Directory of Open Access Journals (Sweden)

    L. Hao

    2015-02-01

    Full Text Available Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of streamflow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River Basin in southern China where massive industrialization has occurred in the region during the past three decades. We found that streamflow increased by 58% and evapotranspiration (ET decreased by 23% during 1986–2013 as a result of an increase in urban areas of three folds and reduction of rice paddy field by 27%. Both highflows and lowflows increased significantly by about 28% from 2002 to 2013. The increases in streamflow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS data. The reduction in ET and increase in streamflow was attributed to the large cropland conversion that overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from a water-dominated to a human-dominated landscape, and thus was considered as one of the extreme types of contemporary hydrologic disturbances. The ongoing large-scale urbanization in the rice paddy-dominated regions in the humid southern China, and East Asia, will likely elevate stormflow volume, aggravate flood risks, and intensify urban heat island effects. Understanding the linkage between land use change and changes in hydrological processes is essential for better management of urbanizing watersheds.

  14. Northward subduction-related orogenesis of the southern Altaids: Constraints from structural and metamorphic analysis of the HP/UHP accretionary complex in Chinese southwestern Tianshan, NW China

    Directory of Open Access Journals (Sweden)

    Mark Scheltens

    2015-03-01

    Full Text Available The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subduction polarity and the way of accretion are the main problems. Southward, northward subduction and multiple subduction models have been proposed. This study focuses on the structural geology of two of the main faults in the region, the South Tianshan Fault and the Nikolaev Line. The dip direction in the Muzhaerte valley is southward and lineations all point towards the NW. Two shear sense motions have been observed within both of these fault zones, a sinistral one, and a dextral one, the latter with an age of 236–251 Ma. Structural analyses on the fault zones show that subduction has been northward rather than southward. The two shear sense directions indicate that the Yili block was first dragged along towards the east due to the clockwise rotation of the Tarim block. After the Tarim block stopped rotating, the Yili block still kept going eastward, inducing the dextral shear senses within the fault zones.

  15. 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

  16. 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

  17. Mesozoic-Cenozoic inversion of the Turpan-Hami Basin, northwest China

    Energy Technology Data Exchange (ETDEWEB)

    Cao, D.; Zhang, P.; Jin, K.; Qian, G.; Mei, M.; Tang, Y.; Shao, L. [China University of Mining and Technology, Beijing (China). Beijing Graduate School

    1996-12-01

    The Turpan-Hami basin, rich in coal and petroleum, is a superimposed basin of three types in different tectonic environments. The basin has undergone a complex tectonic-sedimentary evolution, in which two important stages were the negative inversion from a foredeep to an extensional basin during Early Mesozoic and the positive inversion to a thrust foreland basin in Late Mesozoic-Early Cenozoic. The early normal faults residues are recognized with the addition of tectonic-sedimentary analysis to confirm the basin extension during Jurassic time and its subsequent tectonic inversion. 4 refs., 6 figs.

  18. Effects of climate change on spring wheat phenophase and water requirement in Heihe River basin, China

    Indian Academy of Sciences (India)

    Dongmei Han; Denghua Yan; Xinyi Xu; Yu Gao

    2017-02-01

    Climate change has significantly altered the temperature rhythm which is a key factor for the growth and phenophase of the crop. And temperature change further affects crop water requirement and irrigation system. In the north-west of China, one of the most important crop production bases is Heihe River basin where the observed phenological data is scarce. This study thus first adopted accumulated temperature threshold (ATT) method to define the phenological stages of the crop, and analysed the effect of climate change on phenological stages and water requirement of the crop during growing season. The results indicated the ATT was available for the determination of spring wheat phenological stages. The start dates of all phenological stages became earlier and the growing season length (days) was reduced by 7 days under climate change. During the growing season, water requirement without consideration of phenophase change has been increased by 26.1 mm, while that with consideration of phenophase change was featured in the decrease of water requirement by 50 mm. When temperature increased by 1°C on average, the changes were featured in the 2 days early start date of growing season, 2 days decrease of growing season length, and the 1.4 mm increase of water requirement, respectively.

  19. Responses of natural runoff to recent climatic variations in the Yellow River basin, China

    Science.gov (United States)

    Tang, Y.; Tang, Q.; Tian, F.; Zhang, Z.; Liu, G.

    2013-11-01

    The zero-flow phenomenon appeared frequently in the lower reaches of the Yellow River in China in the 1990s, whereas it has almost disappeared in recent years. The disappearance of the zero-flow phenomenon should be mainly attributed to the recent water management practices. However, little is known about the effects of recent climatic variations on natural runoff. In this study, we investigated the impacts of climatic variations on natural runoff above the Huayuankou station. The results indicate that there was little increase in precipitation, but substantial recovery of natural runoff in the recent period (2003-2011) compared with the low-flow period (1991-2002). The recent precipitation was slightly greater (∼2% of the baseline precipitation in 1960-1990) than precipitation in the low-flow period. However, the recent natural runoff was much larger (∼14% baseline runoff) than runoff in the low-flow period. The runoff reduction in the low-flow period was mainly caused by precipitation decrease. In the recent period, precipitation accounted for a runoff reduction (∼21% baseline runoff), whereas net radiation, wind speed, air temperature, and relative humidity accounted for a runoff increase (∼7.5% baseline runoff). The spatial pattern of the climatic variation is a factor influencing the response of runoff to climatic variations. The reduction in runoff induced by precipitation change was offset up to half by the impacts of changes in net radiation and wind speed at most sub-basins in the recent period.

  20. Genetic Relationship between Natural Gas Dispersal Zone and Uranium Accumulation in the Northern Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    GAN Huajun; XIAO Xianming; LU Yongchao; JIN Yongbin; TIAN Hui; LIU Dehan

    2007-01-01

    The Ordos Basin is well-known for the coexistence of oil, natural gas, coal and uranium. However, there has been little research to discuss the genetic relationship between them. In this paper, a case study of the Zaohuohao area in Dongsheng, Inner Mongolia, China, is conducted to investigate the genetic relationship between the natural gas and the uranium accumulation. Fluid inclusion data from the uranium-bearing sandstone samples indicate that the fluid inclusions formed in a gas-water transition zone. Using the homogeneous temperatures of aqueous inclusions coeval with hydrocarbonbearing inclusions, combined with the buried history and paleo-temperature data, the gas-water transition zone reached the area at about 110 Ma. On the basis of this, the contents of Uranium (U)and Total Organic Carbon (TOC) of the samples were analyzed, and there was no obvious relation between them. With regard to the available data from both publications and this study, it is found that the U mineralization has a spatiotemporal accordance with the gas-water dispersal zone. Thus, it is believed that the natural gas in the gas-water zone is an effective reducer to the U-bearing ground water abundant in oxygen, which is the main factor to U accumulation. This result can be used as the reference to the U mines predicting and prospecting.

  1. Accumulation Mechanisms and Evolution History of the Giant Puguang Gas Field, Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    HAO Fang; GUO Tonglou; DU Chunguo; ZOU Huayao; CAI Xunyu; ZHU Yangming; LI Pingping; WANG Chunwu; ZHANG Yuanchun

    2009-01-01

    Solid bitumens were found throughout the carbonate reservoirs in the Puguang gas field,the largest gas field SO far found in marine carbonates in China,confirming that the Puguang gas field evolved from a paleo-oil reservoir.The fluid conduit system at the time of intensive oil accumulation in the field Was reconstructed,and petroleum migration pathways were modeled using a 3-D model and traced by geochemical parameters.The forward modeling and inversion tracing coincided with each other and both indicated that oils accumulated in the Puguang-Dongyuezhai structure originated from a generative kitchen to the northwest of the Puguang gas field.The deposition of organic-rich Upper Permian source rocks dominated by sapropelic organic matter in the Northeast Sichuan Basin, the development of fluid conduit system that was vertically near-source rock and laterally near-generative kitchen,and the focusing of oils originated from a large area of the generative kitchen,were the three requirements for the formation of the giant paleo-oil reservoir from which the giant Puguang gas field evolved.The Puguang gas field had experienced a three-stage evolution.The post-accumulation processes,especially the organic-inorganic interaction in the hydrocarbon-water-rock system,had not only profoundly altered the composition and characteristics of the petroleum fluids,but also obviously changed the physicochemical conditions in the reservoir and resulted in complicated precipitation and solution of carbonate minerals.

  2. Simulation of hydrological processes in the Zhalong wetland within a river basin, Northeast China

    Directory of Open Access Journals (Sweden)

    X. Q. Feng

    2013-07-01

    Full Text Available Zhalong National Nature Preserve is a large wetland reserve on the Songnen Plain in Northeast China. Wetlands in the preserve play a key role in maintaining regional ecosystem function and integrity. Global climate change and intensified anthropogenic activities in the region have raised great concerns over the change of natural flow regime, wetland degradation and loss. In this study, two key hydrologic components in the preserve, water surface area and water volume, as well as their variations during the period 1985–2006, were investigated with a spatially-distributed hydrologic modeling system (SWAT. A wetland module was incorporated into the SWAT model to represent hydrological linkages between the wetland and adjacent upland areas. The modified modeling system was calibrated with streamflow measurements from 1987 to 1989 and was validated for the period 2005–2006. The calibration achieved a Nash efficiency coefficient (Ens of 0.86, and the validation yielded an Ens of 0.66. In the past 20 yr, water surface area in the Zhalong wetland fluctuated from approximately 200 km2 to 1145 km2 with a rapid decreasing trend through the early 2000s. Consequently, water volume decreased largely in the preserve, especially in the dry seasons. The situation changed following the implementation of a river diversion in 2001. Overall, the modeling yielded plausible estimates of hydrologic changes in this large wetland reserve, building a foundation for assessing ecological water requirements and developing strategies and plans for future water resources management within the river basin.

  3. Determination of a Reasonable Percentage for Ecological Water-Use in the Haihe River Basin, China

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; FENG Hua-Li; ZHAN Che-Sheng; NIU Cun-Wen

    2006-01-01

    An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key aspects for the ecological water requirement (EWR) were analyzed, involving i) the EWR for river system, ii) the EWR for wetlands and lakes, and iii) the EWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of EWR. The results showed that the total ecological water demand in the region was about 3.47-14.56 billion m3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approached 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, respectively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was estimated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

  4. 26Al/10Be burial dating of Xujiayao-Houjiayao site in Nihewan Basin, northern China.

    Directory of Open Access Journals (Sweden)

    Hua Tu

    Full Text Available The Xujiayao-Houjiayao site in Nihewan Basin is among the most important Paleolithic sites in China for having provided a rich collection of hominin and mammalian fossils and lithic artifacts. Based on biostratigraphical correlation and exploratory results from a variety of dating methods, the site has been widely accepted as early Upper Pleistocene in time. However, more recent paleomagnetic analyses assigned a much older age of ∼500 ka (thousand years. This paper reports the application of 26Al/10Be burial dating as an independent check. Two quartz samples from a lower cultural horizon give a weighted mean age of 0.24 ± 0.05 Ma (million years, 1σ. The site is thus younger than 340 ka at 95% confidence, which is at variance with the previous paleomagnetic results. On the other hand, our result suggests an age of older than 140 ka for the site's lower cultural deposits, which is consistent with recent post-infrared infrared stimulated luminescence (pIR-IRSL dating at 160-220 ka.

  5. 26Al/10Be burial dating of Xujiayao-Houjiayao site in Nihewan Basin, northern China.

    Science.gov (United States)

    Tu, Hua; Shen, Guanjun; Li, Haixu; Xie, Fei; Granger, Darryl E

    2015-01-01

    The Xujiayao-Houjiayao site in Nihewan Basin is among the most important Paleolithic sites in China for having provided a rich collection of hominin and mammalian fossils and lithic artifacts. Based on biostratigraphical correlation and exploratory results from a variety of dating methods, the site has been widely accepted as early Upper Pleistocene in time. However, more recent paleomagnetic analyses assigned a much older age of ∼500 ka (thousand years). This paper reports the application of 26Al/10Be burial dating as an independent check. Two quartz samples from a lower cultural horizon give a weighted mean age of 0.24 ± 0.05 Ma (million years, 1σ). The site is thus younger than 340 ka at 95% confidence, which is at variance with the previous paleomagnetic results. On the other hand, our result suggests an age of older than 140 ka for the site's lower cultural deposits, which is consistent with recent post-infrared infrared stimulated luminescence (pIR-IRSL) dating at 160-220 ka.

  6. 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.

  7. Multivariate Regression Analysis and Statistical Modeling for Summer Extreme Precipitation over the Yangtze River Basin, China

    Directory of Open Access Journals (Sweden)

    Tao Gao

    2014-01-01

    Full Text Available Extreme precipitation is likely to be one of the most severe meteorological disasters in China; however, studies on the physical factors affecting precipitation extremes and corresponding prediction models are not accurately available. From a new point of view, the sensible heat flux (SHF and latent heat flux (LHF, which have significant impacts on summer extreme rainfall in Yangtze River basin (YRB, have been quantified and then selections of the impact factors are conducted. Firstly, a regional extreme precipitation index was applied to determine Regions of Significant Correlation (RSC by analyzing spatial distribution of correlation coefficients between this index and SHF, LHF, and sea surface temperature (SST on global ocean scale; then the time series of SHF, LHF, and SST in RSCs during 1967–2010 were selected. Furthermore, other factors that significantly affect variations in precipitation extremes over YRB were also selected. The methods of multiple stepwise regression and leave-one-out cross-validation (LOOCV were utilized to analyze and test influencing factors and statistical prediction model. The correlation coefficient between observed regional extreme index and model simulation result is 0.85, with significant level at 99%. This suggested that the forecast skill was acceptable although many aspects of the prediction model should be improved.

  8. Formation and identification of unresolved complex mixtures in lacustrine biodegraded oil from Nanxiang Basin, China.

    Science.gov (United States)

    Guo, Pengfei; He, Sheng; Zhu, Shukui; Chai, Derong; Yin, Shiyan; Dai, Wei; Zhang, Wanfeng

    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 (oil G574) have fewer types, the polarity difference of compounds in different types is minor, and the relative content of individual compounds is similar. All the features make the compounds in biodegraded oil coelute in GC analysis and form the raised "baseline hump" named UCMs. By injecting standard materials and analyzing mass spectrums of target compounds, it is shown that cyclic alkanes with one to five rings are the major components of UCMs. Furthermore, UCMs were divided into six classes. Classes I and II, composed of alkyl-cyclohexanes, alkyl-naphthanes, and their isomers, are originated from the enrichment of hydrocarbons resistant to degradation in normal oils. Classes III ~ VI, composed of sesquiterpenoids, tricyclic terpanes, low molecular steranes, diasteranes, norhopanes, and their isomers, are probably from some newly formed compounds during the microbial transformation of oil.

  9. Formation and Identification of Unresolved Complex Mixtures in Lacustrine Biodegraded Oil from Nanxiang Basin, China

    Directory of Open Access Journals (Sweden)

    Pengfei Guo

    2014-01-01

    Full Text Available 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 (oil G574 have fewer types, the polarity difference of compounds in different types is minor, and the relative content of individual compounds is similar. All the features make the compounds in biodegraded oil coelute in GC analysis and form the raised “baseline hump” named UCMs. By injecting standard materials and analyzing mass spectrums of target compounds, it is shown that cyclic alkanes with one to five rings are the major components of UCMs. Furthermore, UCMs were divided into six classes. Classes I and II, composed of alkyl-cyclohexanes, alkyl-naphthanes, and their isomers, are originated from the enrichment of hydrocarbons resistant to degradation in normal oils. Classes III ~ VI, composed of sesquiterpenoids, tricyclic terpanes, low molecular steranes, diasteranes, norhopanes, and their isomers, are probably from some newly formed compounds during the microbial transformation of oil.

  10. 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.

  11. A Preliminary Study on the Red Beds in the Northern Heyuan Basin, Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The red beds of the northern Heyuan Basin (Guangdong Province, China) are more than 4,000 m thick.Based on the lithological characters, in ascending order these beds are divided into the Dafeng Formation, Zhutian Formation, and Zhenshui Formation of the Nanxiong Group, Shanghu Formation and Danxia Formation. The Nanxiong Group with relatively mature coarse clastic rocks attains about 2 940 m in thickness. The Dafeng Formation is 837 m thick,consisting of conglomerates and sandy conglomerates; the Zhutian Formation, which is 1,200 m thick, consists of purplish red sandstone with gravels, poorly sorted sandstone, feldspathic quartzose sandstone banded granular conglomerate,siltstone, and sandy mudstone. The Zhutian Formation is rich in calcareous concretions. Heyuannia (Oviraptoridae) and turtle fossils were found in this formation. The Zhenshui Formation deposited to a thickness of 900 m consists of coarse sediments, including granular conglomerate, and gravelly sandstone with well developed cross-beddings; the Shanghu Formation, which is 820 m thick, consists of purplish red granular conglomerate coarse sandstone intercalated with fine siltstone; the Danxia Formation characterized by the Danxia landform is composed of coarse clastic gravels and sandy gravels. The lower part of the Nanxiong Group whence dinosaur eggs and derived oviraptorosaurs come, belongs to the Late Cretaceous. No fossils are found in the Shanghu Formation or the Danxia Formation, but their stratigraphic order of superposition on the Nanxiong Group clearly shows their younger age.

  12. Groundwater circulation and hydrogeochemical evolution in Nomhon of Qaidam Basin, northwest China

    Indian Academy of Sciences (India)

    Yong Xiao; Jingli Shao; Yali Cui; Ge Zhang; Qiulan Zhang

    2017-03-01

    In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysisof the dissolved constituents reveals that groundwater evolves from fresh water (TDS=300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO ₃•Cl– Na•Mg to HCO ₃•Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water andglacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (³H and ¹⁴C) isotope data, range from present to Holocene (~28ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow directionis turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.

  13. Possible Future Climate Change Impacts on the Hydrological Drought Events in the Weihe River Basin, China

    Directory of Open Access Journals (Sweden)

    Fei Yuan

    2016-01-01

    Full Text Available 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 hydrological model driven by climate outputs from three climate models (CMs for future streamflow projections, a probabilistic model for univariate drought assessment, and a copula-based bivariate model for joint drought frequency analysis under historical and future climates. With the observed historical climate data as the inputs, the Variable Infiltration Capacity hydrological model projects an overall runoff reduction in the WRB under the Intergovernmental Panel on Climate Change A1B scenario. The univariate drought assessment found that although fewer hydrological drought events would occur under A1B scenario, drought duration and severity tend to increase remarkably. Moreover, the bivariate drought assessment reveals that future droughts in the same return period as the baseline droughts would become more serious. With these trends in the future, the hydrological drought situation in the WRB would be further deteriorated.

  14. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-05-01

    Full Text Available 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 pollution status and analyze its spatio-temporal variation. Ten sites were classified by the high pollution (HP region and the low pollution (LP region, while 12 months were divided into the wet season and the dry season. It was found that the HP region was mainly in the small tributaries with small drainage areas and low average annual discharges, and it was also found that most of these rivers went through urban areas with industrial and domestic sewages input into the water body. Principal component analysis/factor analysis (PCA/FA was applied to reveal potential pollution sources, whereas absolute principal component score-multiple linear regression (APCS-MLR was used to identify their contributions to each water quality variable. The study area was found as being generally affected by industrial and domestic sewage. Furthermore, the HP region was polluted by chemical industries, and the LP region was influenced by agricultural and livestock sewage.

  15. Impacts of Overgrazing and Reclamation on Soil Resources in Rangeland Ecosystems in Huailai Basin, Hebei, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; HE Wei-ming; JIANG Shi-zhong

    2005-01-01

    The soil constituents and relations between the variation of soil resources and plant communities in three adjacent sites representing the overgrazing, reclamation and comparatively undisturbed communities respectively were quantified and examined in study area in Huailai Basin, Hebei Province, China. There have been significantly greater constituent of C, N, P in the soils of shrubland site. Corg, Ntotal, Navail and Pavail were between 1.18 and 3.90 times more concentrated in the soils of shrubland site in comparison with the other two sites. Although the Ptotal concentration was lower in shrubland soils than in overgrazed rangeland soils, the Pavail concentration, however, was significantly greater in the soils of shrubland site, and increased by 59.1% and even 289.6% in the soils of shrubland site comparing to those in the soils of rangeland and millet field sites. Among the three sites, CV exceeding 40% were found for SO4, Cl, and F ion. The CV of organic carbon also exceeded 40% but only in the soils of millet field site. The highest CV were found for F, SO4 ion in the soils of shrubland and overgrazed rangeland sites, while for Cl and SO4ion in those of millet field site. The results also showed that the introductions of shrubs are of vital importance for the accumulation of soil nutrients and maintenance of soil fertilities, and also for the restoration and reconstruction of desertified ecosystems.

  16. Influences of climate change on water resources availability in Jinjiang Basin, China.

    Science.gov (United States)

    Sun, Wenchao; Wang, Jie; Li, Zhanjie; Yao, Xiaolei; Yu, Jingshan

    2014-01-01

    The influences of climate change on water resources availability in Jinjiang Basin, China, were assessed using the Block-wise use of the TOPmodel with the Muskingum-Cunge routing method (BTOPMC) distributed hydrological model. The ensemble average of downscaled output from sixteen GCMs (General Circulation Models) for A1B emission scenario (medium CO2 emission) in the 2050s was adopted to build regional climate change scenario. The projected precipitation and temperature data were used to drive BTOPMC for predicting hydrological changes in the 2050s. Results show that evapotranspiration will increase in most time of a year. Runoff in summer to early autumn exhibits an increasing trend, while in the rest period of a year it shows a decreasing trend, especially in spring season. From the viewpoint of water resource availability, it is indicated that it has the possibility that water resources may not be sufficient to fulfill irrigation water demand in the spring season and one possible solution is to store more water in the reservoir in previous summer.

  17. The Upper Jurassic-Lower Cretaceous of eastern Heilongjiang, Northeast China: stratigraphy and regional basin history

    Energy Technology Data Exchange (ETDEWEB)

    Sha, J.G.; Matsukawa, M.; Cai, H.W.; Jiang, B.Y.; Ito, M.; He, C.Q.; Gu, Z.W. [Academy of Sinica, Nanjing (China)

    2003-12-01

    In eastern Heilongjiang, the Upper Jurassic is marine and restricted to the Suibin and Dong'an areas, where it is characterized faunally by Callovian-Volgian (Tithonian) bivalves and florally by dinoflagellates. The Lower Cretaceous is widely distributed in eastern Heilongjiang, and characterized faunally by Berriasian-Valanginian bivalves, Barremian-Albian ammonites and Aucellina, and florally by dinoflagellates. To the west, the marine facies grade into non-marine beds. Thus, in the east, for example in the Dong'an and Dajiashan areas, near the northwestern Palaeo-Pacific, the Lower Cretaceous is marine; westward, in the Yunshan, Longzhaogou. Peide, and Zhushan areas, marine and non-marine deposits alternate, whereas further west still, e.g. in the Jixi Basin, non-marine facies are intercalated with marine beds. This regional distribution is indicative of a large, shallow embayment opening eastwards to the Palaeo-Pacific; during the Early Cretaceous successive transgressive-regressive events influenced the climate and biota of eastern Heilongjiang and northeastern China. Many of the Lower Cretaceous sections contain abundant coals, demonstrating that in this region the Early Cretaceous was an important coal-forming period.

  18. Marine Ingressive Events Recorded in Epicontinental Sequences:Example from the Cretaceous Songliao Basin of NE China in Comparison with the Triassic Central Europe Basin of SW Germany

    Institute of Scientific and Technical Information of China (English)

    WANG Pujun; LIU Wanzhu; YIN Xiuzhen; SCHNEIDER Werner; MATTERN Frank

    2002-01-01

    Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow,lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity (Sr/Ba) , alkalinity ( Ca + Mg)/(Si + Al) , reducibility (Ni + Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz -section to be represented for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratigraphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Carnian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epicontinental (cratonic) central Europe Basin. It covered the area in between Great Britain, North Sea, Poland and Southern Germany. It is composed of cyclic deposits of multicolored mudstones, gypsum/anhydrite, and dolomite beds. The two cases of marine ingression - influenced sequences share some common features.

  19. Geochemical Characteristics and Origin of Natural Gases in the Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Sixty-five natural gas samples were collected from 19 oil-gasfields in the Qaidam basin, China. The chemical composition and carbon isotope values of the samples were measured, and the geochemical characteristics and origin of the natural gases were studied. The gases can be divided into biogenic gases, sapropelic oil-type gases, mixed type oil-type gases, coal-type gases and mixed gas. The δ13C1 values of the biogenic gases are very small and the C2+ contents of them are very low, ranging from -68.2‰ to -61.8‰ and 0.06% to 0.20% respectively. They have heavy δD and δ13CCO2, showing a CO2 reduction pathway. They are distributed in the East depression region and derived from the Quaternary source rocks. The sapropelic oil-type gases have small δ13C2 values and high C2+ ranging from -36.6‰ to -28.6‰ and from 33.01% to 47.15% respectively. The mixed type oil-type gases have δ13C2 values and C2+ contents varying from -28.6‰ to -24.8‰ and from 4.81% to 26.06% respectively. Both sapropelic oil-type gases and mixed type oil-type gases are associated with oil-type oils, distributed in the West depression region and derived from the Tertiary saltwater lacustrine sapropelic source rocks and humic source rocks respectively. The δ13C2 values of the coal-type gases are extremely high and the C2+ contents are very low, changing from -23.3‰ to -12.5‰ and from 0.06% to 18.07% respectively. The coal-type gases in the Nanbaxian gasfield and the Lenghu oil-gasfields in the North fault block belt are derived from the Middle Jurassic coal-measures source rocks, whereas those in the West depression region are derived from the Tertiary saltwater lacustrine humic source rocks. Compared with some other basins in China, the natural gases there have obviously heavier δ13C due to the heavier δ13C of different types of kerogens of the Tertiary saltwater lacustrine source rocks in the West depression region of the basin. The mixing of natural gases is common in the West

  20. 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

  1. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

    NARCIS (Netherlands)

    Zeng, Z; Liu, J.; Koeneman, P.H.; Zarate, E.; Hoekstra, A.Y.

    2012-01-01

    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 stu

  2. Assessing water footprint at river basin level: a case study for the Heihe River Basin in Northwest China

    NARCIS (Netherlands)

    Zheng, Z.; Liu, J.; Koeneman, P.H.; Zarate, E.; Hoekstra, A.Y.

    2012-01-01

    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 stu

  3. The early Paleozoic sedimentary-tectonic evolution of the circum-Mangar areas, Tarim block, NW China: Constraints from integrated detrital records

    Science.gov (United States)

    Dong, Shunli; Li, Zhong; Jiang, Lei

    2016-07-01

    The Mangar depression, located in the eastern part of the Tarim basin, had deposited extremely-thick lower Paleozoic sediments, which yields great scientific value and hydrocarbon resource potential. Due to the lack of enough outcrop and core studies, many issues, e.g., early Paleozoic geographical evolution, basin nature and tectonic affinity, are still poorly understood. In this study, we selected circum-Mangar areas (i.e., the South Quruqtagh, Tabei and Tazhong areas), and carried out comprehensive detrital provenance analysis including detrital modal analysis, heavy mineral and trace element analysis, and detrital zircon U-Pb dating on the Middle-Upper Ordovician and Silurian sandstones. The results show that Upper Ordovician-Lower Silurian detrital provenances of the South Quruqtagh and Tabei areas were primarily derived from the intracontinental uplifts in Tarim. Meanwhile, Upper Silurian detrital provenances of the above two areas were mainly derived from the mix of intracontinental uplifts and continental-margin arcs. Dramatic Late Silurian provenance-change suggests the evident tectonic transition of the northern Tarim margin, which is the opening of the South Tianshan back-arc oceanic basin. Combining the previous studies, an integral redefinition model for the Mangar depression has been made. The evolution process of the Mangar depression could be divided into four stages: graben stage (late Neoproterozoic), transitional stage (Cambrian to Middle Ordovician), downwarp stage (Late Ordovician to Early Silurian) and extinction stage (Late Silurian). Hence, the Mangar depression evolved as an aulacogen. Significantly, the evolutional scenario of the Mangar aulacogen was consistent with that of the North Altyn Tagh and the North Qilian, suggesting that the Mangar aulacogen was involved mainly in the Proto-Tethys tectonic realm south to the Tarim block. However, the Late Silurian tectonic activity in the northern Tarim margin did produce massive detrital

  4. Characterization of groundwater in the Ejina Basin,northwest China:hydrochemical and environmental isotopes approaches

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) by titration,and pH.Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute,Chinese Academy of Sciences,Lanzhou,China.The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72,indicating an alkaline nature.The total dissolved solids(TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L.According to the groundwater salinity classification of Robinove et al.(1958),47.4 percent of the samples were brackish and the remainder were fresh water.The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed.The groundwater in the study area was of Na +-HCO 3 type near the bank of the Heihe River and in the southern margin of the basin,while Na +-SO 4 2-Cl type samples were observed in the terminal lake region.In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na +-Cl chemistry.Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio(average 0.000484).The surface water was slightly enriched in Br/Cl(average 0.000711) compared with groundwater.The calculated saturation index(SI) for calcite and dolomite of the groundwater samples range from 0.89 to 1.31 and 1.67 to 2.67 with averaged 0.24 and 0.61,respectively.About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite,and all the samples were below the equilibrium state with gypsum.Using isotope and hydrochemical analyses,this study investigated the groundwater evolution and its residence

  5. The role of scenario analysis in water resources management in Yanqi Basin, Xinjiang, China

    Science.gov (United States)

    Li, N.; Kinzelbach, W. K.; Li, W.; Dong, X.

    2011-12-01

    With the rapid increase of world population and food demand, the demand for water resources is also increasing. At the same time shifts in rain patterns due to global climate change make the water resources situation more uncertain. A global water crisis can therefore not be excluded. The socio-economic and environmental problems induced by such a water crisis are especially prominent in arid and semiarid regions. The Yanqi Basin in Xinjiang province is a typical case study in China's arid and semi-arid areas, where rainfall is scarce and evaporation is extremely high. Thus its water resources have been under great pressure to satisfy the increasing water demand of agriculture and urban and industrial expansion in the last decades. The development has been accompanied by a number of environmental problems. Yanqi Basin is an important cultivated area which is irrigated by water diverted from rivers. Because of the long-term flood irrigation and an inefficient drainage system, the groundwater level under the cultivated area rose, accelerating the phreatic evaporation and leading to increased soil salinization. Simultaneously, the water quantity and quality of Boston Lake have been impaired in past years because of the decreased river discharge and the increased salt flux contained in the drainage discharge. Thus the ecosystems depending on the inflow to and outflow from the lake suffered. The riverine forests in the downstream area were degraded due to declining groundwater levels, and aquatic life as well as downstream water users had to cope with deteriorating water quality. The big challenge for decision makers in the basin is how to balance the justified requirements of agriculture, industrial development and the ecosystem. In order to provide a scientific basis to the decision making process, a scenario analysis was adopted. Here several scenarios are proposed: the basic scenario, scenario 1, describes the status of the year 2008. A second scenario maximizes the

  6. The research of three-dimensional numerical simulation of groundwater-flow: taking the Ejina Basin, Northwest China as example

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Water is a primary controlling factor for economic development and ecological environmental protection in the inland river basins of arid western China. And it is groundwater, as the most important component of total water resources, that plays a dominant role in the development of western China. In recent years, the use-ratio of surface water has been raised, the groundwater recharge rate from surface water has been reduced, and groundwater has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments in the Heihe watershed. Therefore, the study on the change in groundwater levels in recent years, as well as simulating and predicting groundwater levels in the future, have become very significant for im-proving the ecological environment of the Heihe River Basin, to coordinate the water contradiction among upper, middle and lower reaches of Heihe River Basin and to allocate the water resources. The purpose of this study is to analyze the groundwa-ter-level variations of the Ejina region based on a large scale, to develop and evaluate a conceptual groundwater model in Ejina Basin, to establish the groundwater flow model using the experimental observation data and combining Modular Three-Dimensional Groundwater Flow Model (MODFLOW) and GIS software, to simulate the regional hydrologic regime in re-cent 10 years and compare various water-delivery scenarios from midstream, and to determine which one would be the best plan for maintaining and recovering the groundwater levels and increasing the area of Ejina oasis. Finally this paper discusses the pos-sible vegetation changes of Ejina Basin in the future.

  7. 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.

  8. 40Ar/39Ar ages of seamount trachytes from the South China Sea and implications for the evolution of the northwestern sub-basin

    Directory of Open Access Journals (Sweden)

    Xiaohu Li

    2015-07-01

    Full Text Available 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 NW–SE 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.

  9. Land Desertification and it’s Control in Gonghe Basin of Qinghai Plateau, China

    Science.gov (United States)

    Zhang, D.; Gao, S.; Lu, R.

    2009-12-01

    Land desertification is an important environmental and social-economic problems that threatening people’s living conditions and impacting social sustainable development. The Gonghe basin in Qinghai Plateau is a fragile cold alpine area which is one of the places seriously threatened by desertification in China. This paper selected Gonghe basin as a study area to study land sandy desertification and its controlling measures. The engineering measures for sandy desertification control include setting clay sand barrier, Salix cheilophila sand barrier, Tamarix sand barrier, Artemisia sand barrier and straw-checker sand-barriers to fix dunes; the biological measures include closure for natural vegetation recovery, direct seeding forestation, transplanting seedlings, and so on. The combination of engineering and biologic measures can fix dunes 2~3 years earlier than the common single measure; and the costs were basically identical. A synthesized evaluation system established based on experimental results and experience in recent years indicated that the effectiveness of the four kinds of sand barrier for prevention and control of sand in study area were: Tamarix sand barrier > Artemisia sand barrier > clay sand barrier > straw-checker sand-barriers. In addition, different optimized management model can be selected according to local material and geographical place. New plants such as Salix cheilophila and Tamarix, which are available in study area, can change from dead sand barrier to live one set in proper seasons, changing engineering measure to biological one directly speeds the progress of forestation and dunes fixation. In addition, we developed new technique of deep planting Salix cheilophila and Tamarix with their long stem, which can effectively resist drought. We found that it had lower cost and higher live rate, and has a better sand prevention effect than deep planting of Poplar. Finally we choose the optimize management model as follows: Artemisia direct

  10. The tectonic evolution of the Irtysh tectonic belt: New zircon U-Pb ages of arc-related and collisional granitoids in the Kalaxiangar tectonic belt, NW China

    Science.gov (United States)

    Hong, Tao; Klemd, Reiner; Gao, Jun; Xiang, Peng; Xu, Xing-Wang; You, Jun; Wang, Xin-Shui; Wu, Chu; Li, Hao; Ke, Qiang

    2017-02-01

    Precise geochronological constraints of the Irtysh tectonic belt situated between the Saur Island Arc and the Altay Terrane are crucial to a better understanding of the tectonic evolution of the Central Asian Orogenic Belt (CAOB). Recently, we discovered repeatedly deformed arc-related and collisional granitoids in the Kalaxiangar tectonic belt (KTB), which is located in the eastern part of the Irtysh tectonic belt. In this study, we report new whole-rock geochemical, zircon U-Pb and Hf isotopic data of the arc-related and collisional granitoids. Our data reveal that 1) arc-related granodioritic porphyries formed at ca. 382-374 Ma. Recrystallized zircon grains from a (ultra-)mylonitic granodiorite of the Laoshankou zone in the southern KTB display a U-Pb age of ca. 360 Ma; 2) syn-collisional granodioritic porphyries, which distribute along faults and parallel to the cleavage, were emplaced at ca. 367-356 Ma, with εHf(t) values varying from + 7.8 to + 14.2 and Hf model ages from 873 to 459 Ma; 3) a post-collisional A-type granodioritic porphyry, which crosscuts the NW-NNW trending schistosity of the metasedimentary country rocks at a low angle, has an age of ca. 324-320 Ma, while the εHf(t) values range from + 7.6 to + 14.4 with Hf model ages from 850 to 416 Ma; 4) post-collisional strike-slip A-type granite dykes, exposed along strike-slip faults, gave ages between 287 and 279 Ma, whereas the εHf(t) values range from + 4.9 to + 12.7 and the Hf model ages from 995 to 500 Ma; and 5) A-type biotite granite dykes, which intruded along conjugate tension joints, have ages of 274-271 Ma, and εHf(t) values from + 1.5 to + 13.2 with Hf model ages from 1196 to 454 Ma. Consequently, we propose that the collision between the Saur Island Arc and the Altay Terrane occurred in the Early Carboniferous (ca. 367-356 Ma) and the subsequent post-collisional tectonic process continued to the Late Carboniferous (ca. 324-320 Ma). It is further suggested that the Irtysh tectonic belt

  11. Secular Variation in the Storage and Dissipation of Elastic Strain Energy Along the Central Altyn Tagh Fault (86-88.5°E), NW China

    Science.gov (United States)

    Cowgill, E.; Gold, R. D.; Arrowsmith, R.; Friedrich, A. M.

    2015-12-01

    In elastic rebound theory, hazard increases as interseismic strain rebuilds after rupture. This model is challenged by the temporal variation in the pacing of major earthquakes that is both predicted by mechanical models and suggested by some long paleoseismic records (e.g., 1-3). However, the extent of such behavior remains unclear due to a lack of long (5-25 ky) records of fault slip. Using Monte Carlo analysis of 11 offset landforms, we determined a 16-ky record of fault slip for the active, left-lateral Altyn Tagh fault, which bounds the NW margin of the Tibetan Plateau. This history reveals a pulse of accelerated slip between 6.4 and 6.0 ka, during which the fault slipped 9 +14/-2 m at a rate of 23 +35/-5 mm/y, or ~3x the 16 ky average of 8.1 +1.2/-0.9mm/y. These two modes of earthquake behavior suggest temporal variation in the rates of stress storage and release. The simplest explanation for the pulse is a cluster of 2-8 Mw > 7.5 earthquakes. Such supercyclicity has been reported for the Sunda (4) and Cascadia (3) megathrusts, but contrasts with steady slip along the strike-slip Alpine fault (5), for example. A second possibility is that the pulse reflects a single, unusually large rupture. However, this Black Swan event is unlikely: empirical scaling relationships require a Mw 8.2 rupture of the entire 1200-km-long ATF to produce 7 m of average slip. Likewise, Coulomb stress change from rupture on the adjacent North Altyn fault is of modest magnitude and overlap with the ATF. Poor temporal correlation between precipitation and the slip pulse argues against climatically modulated changes in surface loading (lakes/ice) or pore-fluid pressure. "Paleoslip" studies such as this sacrifice the single-event resolution of paleoseismology in exchange for long records that quantify both the timing and magnitude of fault slip averaged over multiple ruptures, and are essential for documenting temporal variations in fault slip as we begin to use calibrated physical

  12. Characteristics of water isotopes and hydrograph separation during the spring flood period in Yushugou River basin, Eastern Tianshans, China

    Indian Academy of Sciences (India)

    Xiaoyan Wang; Zhongqin Li; Edwards Ross; Ruozihan Tayier; Ping Zhou

    2015-02-01

    Many of the river basins in northwest China receive water from melting glaciers and snow in addition to groundwater. This region has experienced a significant change in glacier and snowpack volume over the past decade altering hydrology. Quantifying changes in water resources is vital for developing sustainable strategies in the region. During 2013, a water-isotope source apportionment study was conducted during the spring flood in the Yushugou River basin, northwestern China. The study found significant differences in water isotopes between river water, snowmelt water, and groundwater. During the study period, the isotopic composition of groundwater remained relatively stable. This stability suggests that the groundwater recharge rate has not been significantly impacted by recent hydro-climatic variability. The river water flow rate and water 18O displayed an inverse relationship. This relationship is indicative of snowmelt water injection. The relative contribution of the two sources was estimated using a two-component isotope hydrograph separation. The contribution of snowmelt water and groundwater to Yushugou River were ∼63% and ∼37%, respectively. From the study, we conclude that snowmelt water is the dominant water source to the basin during the spring melt period.

  13. Quantifying the magnitude of the impact of climate change and human activity on runoff decline in Mian River Basin, China.

    Science.gov (United States)

    Fan, Jing; Tian, Fei; Yang, Yonghui; Han, Shumin; Qiu, Guoyu

    2010-01-01

    Runoff in North China has been dramatically declining in recent decades. Although climate change and human activity have been recognized as the primary driving factors, the magnitude of impact of each of the above factors on runoff decline is still not entirely clear. In this study, Mian River Basin (a watershed that is heavily influenced by human activity) was used as a proxy to quantify the contributions of human and climate to runoff decline in North China. SWAT (Soil and Water Assessment Tool) model was used to isolate the possible impacts of man and climate. SWAT simulations suggest that while climate change accounts for only 23.89% of total decline in mean annual runoff, human activity accounts for the larger 76.11% in the basin. The gap between the simulated and measured runoff has been widening since 1978, which can only be explained in terms of increasing human activity in the region. Furthermore, comparisons of similar annual precipitation in 3 dry-years and 3 wet-years representing hydrological processes in the 1970s, 1980s, and 1990s were used to isolate the magnitude of runoff decline under similar annual precipitations. The results clearly show that human activity, rather than climate, is the main driving factor of runoff decline in the basin.

  14. Basic geological features of superimposed basin and hydrocarbon accumulation in Sichuan Basin, China%四川含油气叠合盆地基本特征

    Institute of Scientific and Technical Information of China (English)

    刘树根; 李智武; 孙玮; 邓宾; 罗志立; 王国芝; 雍自权; 黄文明

    2011-01-01

    . break and gradual. According to the type of basin-orogen boundary,developing history and controlling factors,the Sichuan Basin can be divided into five basin-orogen structure units: Unit I-North Sichuan break basin-orogen structure area (controlled by Qinling tectonic domain), Unit Ⅱ-West Sichuan break basin-orogen structure area (controlled by Tibet tectonic domain), Unit Ⅲ-East Sichuan gradual basin-orogen structure area(controlled by Xuefeng tectonic domain), Unit Ⅳ-Southwest Sichuan gradual basin-orogen structure area(controlled jointly by Tibet, Xuefeng and basement tectonic domains)and Unit VCentral Sichuan autochthonous uplift-basin area (controlled by basement tectonic domain).Sichuan Basin is one of major oil-gas-bearing basins in western China, with great natural gas exploration potential owing to abundant hydrocarbon supply and excellent preservation condition. Firstly, five sets of major source rocks developed during the multi-stage basin evolution,with a total thickness of up to 1500 ~2500 m, and high organic carbon content,hydrocarbon generation capacity and gas productivity. Secondly, the Lower Triassic gypsum-salt rocks played an important role in sealing marine oil and gas, while the binary texture and gentle erosion in thrust belt and adjacent foreland basin greatly enhanced the preservation condition in break basin-orogen structure areas. Further, uplift activities since the Late Cretaceous might cause not only the adjustment or destruction of ancient gas pools( gas storage center) ,but also the formation of present gas reservoirs (gas preservation centre ), and fluid cross-formation migration and explosive gas accumulation as well. The multi-phased evolution of superimposed basin, composite-association of multi-stage and multi-direction structures, the heterogeneity of reservoirs and the mobility of natural gas decided the complexity,time-consuming and tortuosity of oil-gas exploration in Sichuan Basin. Thus, just a single exploration

  15. Impact of Climate Change on Hydrologic Extremes in the Upper Basin of the Yellow River Basin of China

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2016-01-01

    Full Text Available To reveal the revolution law of hydrologic extremes in the next 50 years and analyze the impact of climate change on hydrologic extremes, the following main works were carried on: firstly, the long duration (15 d, 30 d, and 60 d rainfall extremes according to observed time-series and forecast time-series by dynamical climate model product (BCC-CSM-1.1 were deduced, respectively, on the basis that the quantitative estimation of the impact of climate change on rainfall extremes was conducted; secondly, the SWAT model was used to deduce design flood with the input of design rainfall for the next 50 years. On this basis, quantitative estimation of the impact of climate change on long duration flood volume extremes was conducted. It indicates that (1 the value of long duration rainfall extremes for given probabilities (1%, 2%, 5%, and 10% of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years and (2 long duration flood volume extremes of given probabilities of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years. The conclusions may provide technical supports for basin level planning of flood control and hydropower production.

  16. From oceanic subduction to continental collision: An overview of HP-UHP metamorphic rocks in the North Qaidam UHP belt, NW China

    Science.gov (United States)

    Zhang, Guibin; Zhang, Lifei; Christy, Andrew G.

    2013-02-01

    The North Qaidam UHPM belt is unique among "continental type" subduction zones in showing well-preserved subducted oceanic relics that predate continental subduction and collision. We review petrologic, thermobarometric, geochemical and geochronological studies for the Yuka, Luliang Shan, Xitieshan and Dulan terranes in this belt. UHP conditions are demonstrated by coesite inclusions in eclogite and country gneiss, and diamond inclusions from garnet peridotite. The relict subducted oceanic lithology crops out in the Shaliuhe cross-section in Dulan terrane; it originated as the floor of a Paleo-Qilian Ocean that existed between Qaidam and Qilian blocks before the early Ordovician. Whereas most eclogites of this belt are derived from mafic rocks of either a Neoproterozoic continental rift or incipient oceanic basin setting, which were subducted along with continental rocks in the early Paleozoic. The data, especially the two protolith sources for eclogites, demonstrate tectonic evolution of the North Qaidam UHPM belt from oceanic subduction to continental collision.

  17. 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.

  18. Impact of land-use change on hydrological processes in the Maying River basin, China

    Institute of Scientific and Technical Information of China (English)

    WANG Genxu; ZHANG YU; LIU Guimin; CHEN Lin

    2006-01-01

    Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of China. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest China, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors,i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large areas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 28.12%, a base flow decline of 35.32%, a drop in the maximum peak discharge of 35.77%, and mean discharge decreases in spring and autumn of 36.05% and 24.87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73%-81%,and that to the influence of base flow reaching 62%-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.

  19. Secondary salinization and evapotranspiration under mulched drip irrigation condition in Tarim River basin of northwestern China

    Science.gov (United States)

    Tian, Fuqiang; Hu, Hongchang; Zhang, Zhi; Hu, Heping

    2013-04-01

    The secondary salinization induced by irrigation has been presented as a crucial threat to agriculture all over the world, especially in semi-arid and arid regions. Mulched drip irrigation (MDI), as a new micro-irrigation approach incorporating surface drip irrigation method and film mulching technique, has been widely applied in water scarce regions including Tarim River basin of northwestern China. However, salts are likely to build up in the surface soil due to the deficient leaching water in such an irrigation condition. To explore this new kind of secondary salinization issue, the oasis eco-hydrology experimental research station were established in 2008 in a cotton field of Xinjiang, northwestern China. More than 40,000 soil samples were collected to monitor soil moisture and salinity condition within the 1.5 meter depth. The patterns of soil salinity distribution under MDI along the horizontal direction as well as vertical direction have been explored. The results did show that secondary salinization tends to occur in the experimental field under mulched drip irrigation, and winter flush could leach most soil salt in the root zone into groundwater and keep salt balance to mitigate the soil salinization. Meanwhile, soil salt always migrates with the soil water flux such as irrigation and groundwater recharge. Therefore the understanding of water balance is of great importance for estimating soil salinity accumulation, of which evapotranspiration (ET) is the key process, especially in the semi-arid and arid area. In our study, in order to quantify the relation between salinity balance and water balance, ET were derived from a range of measurement systems including eddy covariance, soil water budget (gravimetric methods, Hydra probe, TDT probe and groundwater table sensor, et al.), sap flow and portable photosynthetic system during cotton growing period. Our study is unique in its focus on ET scale issue ranging from leaf and plant scale to field. The up

  20. Socio-hydrologic Perspectives of the Co-evolution of Humans and Water in the Tarim River Basin, Western China

    Science.gov (United States)

    Liu, Ye; Tian, Fuqiang; Hu, Heping; Liu, Dengfeng; Sivapalan, Murugesu

    2013-04-01

    Socio-hydrology studies the co-evolution of coupled human-water systems, which is of great importance for long-term sustainable water resource management in basins suffering from serious eco-environmental degradation. Process socio-hydrology can benefit from the exploring the patterns of historical co-evolution of coupled human-water systems as a way to discovering the organizing principles that may underpin their co-evolution. As a self-organized entity, the human-water system in a river basin would evolve into certain steady states over a sufficiently long time but then could also experience sudden shifts due to internal or external disturbances that exceed system thresholds. In this study, we discuss three steady states (also called stages in the social sciences, including natural, human exploitation and recovery stages) and transitions between these during the past 1500 years in the Tarim River Basin of Western China, which a rich history of civilization including its place in the famous Silk Road that connected China to Europe. Specifically, during the natural stage with a sound environment that existed before the 19th century, shifts in the ecohydrological regime were mainly caused by environmental changes such river channel migration and climate change. During the human exploitation stages in the 5th and again in the 19th-20th centuries, however, humans gradually became the main drivers for system evolution, during which the basin experienced rapid population growth, fast socio-economic development and intense human activities. By the 1970s, after 200 years of colonization, the Tarim River Basin evolved into a new regime with vulnerable ecosystem and water system, and suffered from serious water shortages and desertification. Human society then began to take a critical look into the effects of their activities and reappraise the impact of human development on the ecohydrological system, which eventually led the basin into a treatment and recovery stage

  1. Novel early flood warning in the Huaihe River basin in east-central China using the TIGGE database

    Science.gov (United States)

    He, Y.; Cloke, H.; Li, Z.; Wetterhall, F.; Pappenberger, F.

    2009-04-01

    Flooding is a wide spread and devastating natural disaster worldwide. Floods that took place in the last decade in China were ranked the worst amongst recorded floods worldwide in terms of the number of human fatalities and economic losses (Munich Re-Insurance). Rapid economic development and population expansion into low lying flood plains has worsened the situation. The last decade has seen an increase in flood preparedness across all levels of society in China. Current conventional flood prediction systems in China are neither suited to the perceptible climate variability nor the rapid pace of urbanization sweeping the country. Flood prediction systems from short-term (a few hours) to medium-term (a few days) need to be revisited and adapted to changing socio-economic and hydro-climatic realities. The latest technology requires implementation of multiple numerical weather prediction systems. The availability of a number of global ensemble weather prediction systems through the ‘THORPEX Interactive Grand Global Ensemble' (TIGGE) offers a good opportunity for an effective state-of-the-art early forecasting system. A prototype of a Novel Flood Early Warning System (NEWS) using the TIGGE database is tested in the Huai River basin located in east-central China. It is the first early flood warning system in China that uses the massive TIGGE database cascaded with river catchment models, the Xinanjiang model and a 1-D hydraulic model, to predict river discharge and flood inundation. Results from selected flood events will be presented.

  2. Methane microseepage from different sectors of the Yakela condensed gas field in Tarim Basin, Xinjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junhong, E-mail: Tang_jhjh@tom.com [Dept. of Environmental Engineering and Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Yin Haoyong [Dept. of Environmental Engineering and Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Wang Guojian [Wuxi Research Institute of Petroleum Geology, Research Institute of Petroleum Exploration and Production, SINOPEC, Wuxi, Jiangsu 214151 (China); Chen Yueyuan [Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products, Ministry of Land and Resources, Lanzhou 730070 (China)

    2010-08-15

    Research highlights: {yields} Dry soil over a petroleum field may give positive fluxes of CH{sub 4} due to microseepage from the underground hydrocarbon accumulations. {yields} Microseepage flux is influenced by subsurface geo-structural features and gas-oil setting. {yields} The {sup 13}C/{sup 12}C ratios of CH{sub 4} in the flux chambers demonstrates that seeping methane is thermogenic. - Abstract: Methane microseepage is the result of natural gas migration from subsurface hydrocarbon accumulations to the Earth's surface, and it is quite common in commercial petroleum fields. While the role of microseepage as a pathfinder in petroleum exploration has been known for about 80 a, its significance as an atmospheric CH{sub 4} source has only recently been studied, and flux data are currently available only in the USA and Europe. With the aim of increasing the global data-set and better understanding flux magnitudes and variabilities, microseepage is now being extensively studied in China. A static flux chamber method was recently applied to study microseepage emissions into the atmosphere in four different sectors of the Yakela condensed gas field in Tarim Basin, Xinjiang, China, and specifically in: (a) a faulted sector, across the Luntai fault systems; (b) an oil-water interface sector, at the northern margin of the field; (c) an oil-gas interface sector, in the middle of the field; (d) an external area, outside the northern gas field boundaries. The results show that positive CH{sub 4} fluxes are pervasive in all sectors and therefore, only part of the CH{sub 4} migrating from the deep oil-gas reservoirs is consumed in the soil by methanotrophic oxidation. The intensity of gas seepage seems to be controlled by subsurface geologic settings and lateral variabilities of natural gas pressure in the condensed gas field. The highest CH{sub 4} fluxes, up to {approx}14 mg m{sup -2} d{sup -1} (mean of 7.55 mg m{sup -2} d{sup -1}) with higher spatial variability

  3. 中国大陆地区沉积盆地的热状况、热历史和生烃史%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)

    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.

  4. Analysis and prediction of reference evapotranspiration with climate change in Xiangjiang River Basin, China

    Directory of Open Access Journals (Sweden)

    Xin-e Tao

    2015-10-01

    Full Text Available Reference evapotranspiration (ET0 is often used to estimate actual evapotranspiration in water balance studies. In this study, the present and future spatial distributions and temporal trends of in the Xiangjiang River Basin (XJRB in China were analyzed. during the period from 1961 to 2010 was calculated with historical meteorological data using the FAO Penman-Monteith (FAO P-M method, while during the period from 2011 to 2100 was downscaled from the Coupled Model Intercomparison Project Phase 5 (CMIP5 outputs under two emission scenarios, representative concentration pathway 4.5 and representative concentration pathway 8.5 (RCP45 and RCP85, using the statistical downscaling model (SDSM. The spatial distribution and temporal trend of were interpreted with the inverse distance weighted (IDW method and Mann-Kendall test method, respectively. Results show that: (1 the mean annual of the XJRB is 1 006.3 mm during the period from 1961 to 2010, and the lowest and highest values are found in the northeast and northwest parts due to the high latitude and spatial distribution of climatic factors, respectively; (2 the SDSM performs well in simulating the present and can be used to predict the future in the XJRB; and (3 CMIP5 predicts upward trends in annual under the RCP45 and RCP85 scenarios during the period from 2011 to 2100. Compared with the reference period (1961 to 1990, increases by 9.8%, 12.6%, and 15.6% under the RCP45 scenario and 10.2%, 19.1%, and 27.3% under the RCP85 scenario during the periods from 2011 to 2040, from 2041 to 2070, and from 2071 to 2100, respectively. The predicted increasing under the RCP85 scenario is greater than that under the RCP45 scenario during the period from 2011 to 2100.

  5. Assessment of River Habitat Quality in the Hai River Basin, Northern China

    Directory of Open Access Journals (Sweden)

    Yuekui Ding

    2015-09-01

    Full Text Available 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; and nearly 50% of the sites; accounting for a river length of 1.65 × 104 km; had either poor or bad habitats. River habitat degradation was attributable to the limited width of the riparian zone (≤5 m; lower coverage of riparian vegetation (≤40%; artificial land use patterns (public and industrial land; frequent occurrence of farming on the river banks and high volumes of solid waste (nearly 10 m3; single flow channels; and rare aquatic plants (≤1 category. At the regional scale; intensive artificial land use types caused by urbanization had a significant impact on the RHQ in the HRB. RHQ was significantly and negatively correlated with farmland (r = 1.000; p < 0.01 and urban land (r = 0.998; p < 0.05; and was significantly and positively correlated with grassland and woodland (r = 1.000; p < 0.01. Intensive artificial land use; created through urbanization processes; has led to a loss of the riparian zone and its native vegetation; and has disrupted the lateral connectivity of the rivers. The degradation of the already essentially black rivers is exacerbated by poor longitudinal connectivity (index of connectivity is 2.08–16.56; caused by reservoirs and sluices. For river habitat rehabilitation to be successful; land use patterns need to be changed and reservoirs and sluices will have to be regulated.

  6. Kinetic Modeling of Diagenesis of Eogene Lacustrine Sandstone Reservoirs in the Jianghan Basin, Southeastern China

    Institute of Scientific and Technical Information of China (English)

    倪师军; 卿海若; 唐建武; 周美夫; 李泽琴

    2002-01-01

    In the Tuoshi oilfield, located in the Cenozoic Jianghan Basin of southeastern China, there have been found hydrocarbon reservoirs hosted in lacustrine sandstones of the Eogene Xingouzui Formation. The main diagenetic features identified in these sandstones include the dissolution of detrital K-feldspar and albite grains, the precipitation of quartz as overgrowths and/or cements, and the precipitation and/or transformation of clay minerals. These diagenetic features were interpreted to have occurred in early, intermediate and late stages, based on the burial depth. The kinetics of fluid-mineral reactions and the concentrations of aqueous species at each stage of diagenesis were simulated numerically for these lacustrine sandstones, using a quasi-stationary state approximation that incorporates simultaneous chemical reactions in a time-space continuum. During the early diagenetic stage, pore fluid was weakly acidic, which resulted in dissolution of K-feldspar and albite and, therefore, led to the release of K + , Na + , Al3 + and SiO2(aq) into the diagenetic fluid. The increased K+ , Na + , Al3+ and SiO2(aq) concentrations in the diagenetic fluid caused the precipitation of quartz, kaolinite and illite. At the beginning of the intermediate diagenetic stage the concentration of H + was built up due to the decomposition of organic matter, which was responsible for further dissolution of K-feldspar and albite and precipitation of quartz, kaolinite, and illite. During the late diagenetic stage, the pore fluid was weakly alkaline, K-feldspar became stable and was precipitated with quartz and clay minerals.When the burial depth was greater than 3000 m, the pore fluids became supersaturated with respect to albite, but undersaturated with respect to quartz, resulting in the precipitation of albite and the dissolution of quartz. The diagenetic reactions forecasted in the numerical modeling closely matched the diagenetic features identified by petrographic examination, and

  7. Simulation of hydrological processes in the Zhalong Wetland within a river basin, Northeast China

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    X. Q. Feng

    2012-12-01

    Full Text Available Zhalong National Nature Preserve is a large wetland reserve on the Songnen Plain in Northeast China. Wetlands in the preserve play a key role in maintaining regional ecosystem function and integrity. Global climate change and intensified anthropogenic activities in the region have raised great concerns over the change of natural flow regime, wetland degradation and losses. In this study, two key hydrologic components in the preserve, open water area and storage, as well as their variations during the period 1985–2006 were investigated with a spatially-distributed hydrologic modeling system, SWAT. A wetland module was incorporated into the SWAT model to represent hydrological linkages between the wetland and adjacent upland areas. The modified modeling system was calibrated with streamflow measurements from 1987 to 1989, in a Nash efficiency coefficient (Ens of 0.86, and was validated for the period 2005–2006, in an Ens of 0.66. In the past 20 yr, open water area in the Zhalong Wetland fluctuated from approximately 200 km2 to 1145 km2 with a rapid decreasing trend through the early 2000s. Consequently, open water storage in the preserve decreased largely, especially in the dry seasons. The situation changed following the implementation of a river diversion in 2001. Overall, the modeling yielded plausible estimates of hydrologic changes in this large wetland reserve, building a foundation for assessing ecological water requirements and developing strategies and plans for water resources management within the river basin.

  8. Liquefaction in western Sichuan Basin during the 2008 Mw 7.9 Wenchuan earthquake, China

    Science.gov (United States)

    Liu-Zeng, Jing; Wang, Peng; Zhang, Zhihui; Li, Zhigang; Cao, Zhenzhong; Zhang, Jinyu; Yuan, Xiaoming; Wang, Wei; Xing, Xiuchen

    2017-01-01

    Strong ground shaking during the 2008 Mw 7.9 Wenchuan earthquake, which occurred in the foothills of the Longmen Shan in southwestern China, resulted in widespread coseismic deformation features, such as liquefaction and water ejection. We present a systematic survey of the soil liquefaction and water ejection features caused by this major earthquake. The majority of liquefaction sites occurred along major alluvial fan-building rivers, where the water table was a few meters below the surface. While there is no clear correlation between water fountain height and peak ground acceleration, 58% of liquefaction sites are located 20-35 km from the Beichuan fault. Clusters of sites with anomalously high (> 2 m) water ejections are located near the surface projection of the Range Front blind thrust and its splay faults. The density of anomalously high eruptions within the window surrounding the Range Front blind thrust is 3-6 times greater than outside this region. Our results suggest that geologic structures may play a role in augmenting liquefaction intensity and shaking-related seismic hazards in sedimentary basins. We speculate that the mechanism could be the amplification of shaking by fault zone structures. Alternatively, faults may act as pathways with increased vertical permeability, allowing fluids from deeper confined aquifers to migrate to and enhance liquefaction of the upper soil, as proposed previously by Wang (2007). Liquefaction associated with the Wenchuan earthquake thus demonstrates the importance of considering geologic structures other than the primary earthquake-producing fault in seismic hazard evaluation and earthquake resistance design in areas with similar geologic and hydrological settings.

  9. Measurements of energy and water vapor fluxes over different surfaces in the Heihe River Basin, China

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    S. Liu

    2010-11-01

    Full Text Available 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 the differences between the sensible heat fluxes measured by EC and LAS. The results show that the main EC source areas were within a radius of 250 m at all sites. The main source area for the LAS (with a path length of 2390 m stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed according to season and site, and there were characteristic seasonal variations in the energy and water vapor fluxes at all sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The evapotranspiration (ET at YK was larger than those at the other two sites. The monthly ET reached its peak in July at YK and in June at GT in both 2008 and 2009, while it reached its peak in August at AR in 2008 and in June in 2009. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the energy imbalance of EC, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.

  10. Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China.

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    Min Wang

    Full Text Available In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions play a major role in the shale oil occurrence (free or absorbed state, amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1 Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2 There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3 Pores in lacustrine shale are well developed when the organic matter maturity (Ro is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable.

  11. Relationship between catchment characteristics and forms of nitrogen in Cao-E River Basin, Eastern China

    Institute of Scientific and Technical Information of China (English)

    JIN Shuquan; LU Jun; CHEN Dingjiang; SHEN Yena; SHI Yiming

    2009-01-01

    The distribution of different nitrogen forms and their spatial and temporal variations in different pollution types of tributaries or reaches were investigated. Based on the catchments characteristics the tributaries or reaches can be classified into 4 types including headwater in mountainous areas (type I), agricultural non-point source (NPS) pollution in rural areas (type II), municipal and industrial pollution in urban areas (type III), and combined pollution in the main stream (type IV). Water samples were collected monthly from July 2003 to June 2006 in the Cao-E River basin in Zhejiang, Eastern China. The concentrations of NO3-N, NH4+-N, and total nitrogen (TN) were measured. The mean concentrations of NO3-N were in the order type IV > type II> type III > type I, whereas, NH4+-N, total organic nitrogen (TON), and TN were in the order type III > type IV > type II> type I. In headwater and rural reaches, CNO3-N was much higher than CNH4+-N. In urban reaches, TON and NH4+-N were the main forms, accounting for 54.7% and 32.1% of TN, respectively. In the whole river system, CNH4+-N decrease with increasing distance from cities, and CNO3-N increased with the increasing area of farmland in the catchments. With increased river flow, the CNO3-N increased and the CNH4+-N decreased in all types of reaches, while the variations of CTON and CTN were different. For TN, the concentration may be decreased with the increase of river flow, but the export load always increased.

  12. Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China

    Institute of Scientific and Technical Information of China (English)

    Xin He; Zhong-Qiang Chen; Zongsheng Lu; Jun Li; Wei Hu; Shengfu Li; Zhitao Xu

    2015-01-01

    Abundant well-preserved tubular fossils of caddisfly (Insecta: Trichoptera) larval cases are reported from the Early Cretaceous Madongshan and Naijiahe formations of the Liupanshan Basin, Ningxia Province, western China. Most cases were mainly preserved in life position and densely packed in various layers. Individual cases in each layer tended to be same in size and were erect and parallel to one another and open at both ends. In a transverse section cut perpendicular to the long axis of the cases, individual case appears to form a rounded ring. Small cases are elliptic in a cross-section oblique to the long axis of the cases. Tube walls are nearly subparallel to one another in longitudinal section with both ends being open. The caudal end of the case slightly tapers and usually points downward. The cases were closely packed, almost touching with one another and lacking bifurcate or connecting struc-ture. The overwhelming majority of cases were partially or fully filled with calcite. The case wall em-braces a medium particle layer flanked by inner and outer organic layers. Individual particles are ovate in outline and comprise cryptocrystalline or ganic pellets. SEM imaging shows that those pellets are sub-cylindrical in outline and elliptic in cross section, and are made primarily of calcium carbonate. All features observed justify the assignment of the Liupanshan caddisfly cases to ichnogenus Coprindusia. The extinct insect Ningxiapsyche fangi was found in association with the Liupanshan caddisfly larval cases, and thus could be the candidate of the potential trace-maker.

  13. Potential recoverable natural gas resources in China

    Institute of Scientific and Technical Information of China (English)

    Liu Chenglin; Zhu Jie; Che Changbo; Liu Guangdi

    2008-01-01

    Natural gas resources in China are abundant. The undiscovered recoverable natural gas resources in China are estimated to be 19.27×1012 m3. Natural gas is mainly distributed in the middle and west China and offshore areas of China. The Tarim Basin, Sichuan Basin, Ordos Basin, East China Sea Basin, Tsaidam Basin, Yinggehai Basin, and Qiongdongnan Basin are the main gas-beating basins. The natural gas resources are not distributed evenly and are under-explored in China. The deeper horizons in east China, foreland basins and craton paleo-uplifts in the middle and west China, and the offshore basins are the main exploration areas in the future.