Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to di...Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to discuss this question. Among those minerals in Quaternary sediments, magnetite was rarely studied. This paper presents element geochemistry and backscatter images of detrital magnetites from the Quaternary sediments in the Yichang area of Hubei Province. By discussing the provenance changes of detratic magnetites, we suggested the birth time of the Three Gorges of the Yangtze River.展开更多
On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consi...On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.展开更多
The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigat...The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigated using high precision 3-D seismic data.The NW-SE faults were generated in Oligocene,causing the formation of a series of folds related to transpression faults in the Niuzhong and Dongping area.After the Miocene,with the continuous extension of the Altyn Tagh strike-slip fault zone,the EW trending faults began to develop massively in Altyn slope.The activity of near EW trending faults and large-scale uplift of the bedrock in the northern Niuzhong area shared most of the compression torsion in Niuzhong and Dongping area,consequently,the activity of NW-SE trending faults weakened significantly after the Miocene.Then good hydrocarbon source rocks developed in the inherited Jurassic sags.The faults were effective pathways for oil and gas migration in Dongping and Niuzhong areas,and the oil and gas charging time matched well with the formation period of the NW-SE trending faults and their related structures,making the fault-related anticlines favorable targets for oil and gas accumulation.The Niuzhong area has been less affected by the Cenozoic movement after the Miocene,and thus has better conditions for gas reservoir preservation.展开更多
With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,...With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,fault throw analyzing,and balanced profile restoration,it is pointed out that the transtensional fault system in the Ziyang 3-D seismic survey consists of the northeast-trending F_(I)19 and F_(I)20 fault zones dominated by extensional deformation,as well as 3 sets of northwest-trending en echelon normal faults experienced dextral shear deformation.Among them,the F_(I)19 and F_(I)20 fault zones cut through the Neoproterozoic to Lower Triassic Jialingjiang Formation,presenting a 3-D structure of an“S”-shaped ribbon.And before Permian and during the Early Triassic,the F_(I)19 and F_(I)20 fault zones underwent at least two periods of structural superimposition.Besides,the 3 sets of northwest-trending en echelon normal faults are composed of small normal faults arranged in pairs,with opposite dip directions and partially left-stepped arrangement.And before Permian,they had formed almost,restricting the eastward growth and propagation of the F_(I)19 fault zone.The F_(I)19 and F_(I)20 fault zones communicate multiple sets of source rocks and reservoirs from deep to shallow,and the timing of fault activity matches well with oil and gas generation peaks.If there were favorable Cambrian-Triassic sedimentary facies and reservoirs developing on the local anticlinal belts of both sides of the F_(I)19 and F_(I)20 fault zones,the major reservoirs in this area are expected to achieve breakthroughs in oil and gas exploration.展开更多
在中国式现代化视域中,我国区域国别学学科建设的理论意义在于进一步繁荣和发展我国哲学社会科学,为中国式现代化提供有力知识支撑,实践意义在于为中国式现代化创建良好的周边、区域和全球环境。其建设路径需要以服务中国式现代化对外...在中国式现代化视域中,我国区域国别学学科建设的理论意义在于进一步繁荣和发展我国哲学社会科学,为中国式现代化提供有力知识支撑,实践意义在于为中国式现代化创建良好的周边、区域和全球环境。其建设路径需要以服务中国式现代化对外战略需求为导向,从国家层面完善区域国别学学科建设的顶层设计和战略谋划,高校层面则需要构建以学科属性为引领(Led by the Nature of the Discipline)、以在地化为主导(Led by Localization)、以国际视野为指向(Guided by an International Vision)和以师资队伍建设为中心(Centered on Faculty Team Building)的“LLGC”模式,为中国式现代化构筑区域国别学人才培养“蓄水池”。展开更多
In the paper, we use the Central Moment Tensor (CMT) solution acquired by Harvard Univ. for the earthquakes occurred in Kurile Islands to analyze the consistent focal mechanism in the area and propose the idea of maki...In the paper, we use the Central Moment Tensor (CMT) solution acquired by Harvard Univ. for the earthquakes occurred in Kurile Islands to analyze the consistent focal mechanism in the area and propose the idea of making earthquake prediction based on the consistent parameter a of focal mechanism and stress field. The results from the study indicate that before Mw greater than or equal 7.5 earthquakes, the consistent parameter a decreases, which starts about 10-110 days and ends about 30-2 days before the great earthquakes. Although the phenomenon is not totally the same for individual earthquake, the difference is not large. Certainly, the phenomenon should be tested by time for its reliability. However, it should not be random that the focal mechanism of Mw greater than or equal 5.3 earthquakes are consistent successively with the stress field in an area of several hundreds kilometers in length. It should be a phenomenon of predictive significance. When the accumulated earthquake examples are sufficient, uniform judgment criteria and prediction principles can be stipulated then.展开更多
Correlation-coefficient fields are widely used in short-term climate prediction research. The most frequently used significance test method for the correlation-coefficient field was proposed by Livezey, in which the n...Correlation-coefficient fields are widely used in short-term climate prediction research. The most frequently used significance test method for the correlation-coefficient field was proposed by Livezey, in which the number of significantcorrelation lattice(station) points on the correlation coherence map is used as the statistic. However, the method is based on two assumptions:(1) the spatial distribution of the lattice(station) points is uniform;and(2) there is no correlation between the physical quantities in the correlation-coefficient field. However, in reality, the above two assumptions are not valid.Therefore, we designed a more reasonable method for significance testing of the correlation-coefficient field. Specifically, a new statistic, the significant-correlation area, is introduced to eliminate the inhomogeneity of the grid(station)-point distribution, and an empirical Monte Carlo method is employed to eliminate the spatial correlation of the matrix.Subsequently, the new significance test was used for simultaneous correlation-coefficient fields between intensities of the atmospheric activity center in the Northern Hemisphere and temperature/precipitation in China. The results show that the new method is more reasonable than the Livezey method.展开更多
1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et ...1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et al.,2006).The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south.展开更多
Study on the effectiveness of fractures is of great significance for understanding reservoir types and properties, identifying reservoir seepage mechanisms and delineating the reasonable development technologies and p...Study on the effectiveness of fractures is of great significance for understanding reservoir types and properties, identifying reservoir seepage mechanisms and delineating the reasonable development technologies and policies. In this paper, the Changxing reef-flat facies reservoirs in the Yuanba area, Sichuan Basin, was taken as an example. After the characteristics of natural fractures were evaluated, the effectiveness of different types of fractures was investigated by using core, thin section, imaging logging and production performance data. Then, the main geological factors that influence fracture effectiveness were analyzed, and the development significance of effective fractures was illustrated. The following results are obtained. (1) Structural fractures and diagenetic fractures are mainly developed in Changxing Fm carbonate reservoirs in Yuanba area. Structural fractures include shear fractures and extensional fractures, and diagenetic fractures include dissolution fractures, structural-dissolution fractures and pressure-solution fractures. (2) High-angle structural fractures are the most effective, followed by horizontal fractures and then oblique fractures, and pressure-solution fractures are the least effective. (3) Among structural fractures, those of NW–SE and nearly E–W oriented are more effective than those of the NE–SW oriented. (4) The earlier the fractures are formed, the more likely they are to be filled with calcite or dolomite and become invalid. (5) The fractures which are formed before or during the oil and gas charging tend to be filled with organic matters and become invalid. The late fractures which are formed after oil and gas charging are mostly effective and their contribution to the reservoir is the greatest. (6) The fractures nearly parallel to the maximum principal stress direction of current ground stress present good effectiveness with large opening. It is concluded that the opening and filling features of natural fractures help determine if fractures are effective or not, and the development degree, distribution and combination features of effective fractures and the matching relationship between fractures and pores further dominate the development significance of effective fractures;that when the effective fractures are more developed and are connected with each other to form a large-scale fracture network, separated and isolated pores and dissolved fractures and cavities can be connected, as a result, the physical properties of reservoirs are improved and high production rates of gas wells are realized.展开更多
基金financially supported by the National Natural Science Foundation of China (grants No.41072083 and 4157209)
文摘Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to discuss this question. Among those minerals in Quaternary sediments, magnetite was rarely studied. This paper presents element geochemistry and backscatter images of detrital magnetites from the Quaternary sediments in the Yichang area of Hubei Province. By discussing the provenance changes of detratic magnetites, we suggested the birth time of the Three Gorges of the Yangtze River.
基金The subject was funded by Xi'an Laboratory of Loess and Quaternary Geology, Academia Sinica
文摘On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.
基金Supported by the PetroChina Project(2016ZX05003-006).
文摘The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigated using high precision 3-D seismic data.The NW-SE faults were generated in Oligocene,causing the formation of a series of folds related to transpression faults in the Niuzhong and Dongping area.After the Miocene,with the continuous extension of the Altyn Tagh strike-slip fault zone,the EW trending faults began to develop massively in Altyn slope.The activity of near EW trending faults and large-scale uplift of the bedrock in the northern Niuzhong area shared most of the compression torsion in Niuzhong and Dongping area,consequently,the activity of NW-SE trending faults weakened significantly after the Miocene.Then good hydrocarbon source rocks developed in the inherited Jurassic sags.The faults were effective pathways for oil and gas migration in Dongping and Niuzhong areas,and the oil and gas charging time matched well with the formation period of the NW-SE trending faults and their related structures,making the fault-related anticlines favorable targets for oil and gas accumulation.The Niuzhong area has been less affected by the Cenozoic movement after the Miocene,and thus has better conditions for gas reservoir preservation.
基金Supported by the Key Project of National Natural Science Foundation of China(42330810).
文摘With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,fault throw analyzing,and balanced profile restoration,it is pointed out that the transtensional fault system in the Ziyang 3-D seismic survey consists of the northeast-trending F_(I)19 and F_(I)20 fault zones dominated by extensional deformation,as well as 3 sets of northwest-trending en echelon normal faults experienced dextral shear deformation.Among them,the F_(I)19 and F_(I)20 fault zones cut through the Neoproterozoic to Lower Triassic Jialingjiang Formation,presenting a 3-D structure of an“S”-shaped ribbon.And before Permian and during the Early Triassic,the F_(I)19 and F_(I)20 fault zones underwent at least two periods of structural superimposition.Besides,the 3 sets of northwest-trending en echelon normal faults are composed of small normal faults arranged in pairs,with opposite dip directions and partially left-stepped arrangement.And before Permian,they had formed almost,restricting the eastward growth and propagation of the F_(I)19 fault zone.The F_(I)19 and F_(I)20 fault zones communicate multiple sets of source rocks and reservoirs from deep to shallow,and the timing of fault activity matches well with oil and gas generation peaks.If there were favorable Cambrian-Triassic sedimentary facies and reservoirs developing on the local anticlinal belts of both sides of the F_(I)19 and F_(I)20 fault zones,the major reservoirs in this area are expected to achieve breakthroughs in oil and gas exploration.
文摘在中国式现代化视域中,我国区域国别学学科建设的理论意义在于进一步繁荣和发展我国哲学社会科学,为中国式现代化提供有力知识支撑,实践意义在于为中国式现代化创建良好的周边、区域和全球环境。其建设路径需要以服务中国式现代化对外战略需求为导向,从国家层面完善区域国别学学科建设的顶层设计和战略谋划,高校层面则需要构建以学科属性为引领(Led by the Nature of the Discipline)、以在地化为主导(Led by Localization)、以国际视野为指向(Guided by an International Vision)和以师资队伍建设为中心(Centered on Faculty Team Building)的“LLGC”模式,为中国式现代化构筑区域国别学人才培养“蓄水池”。
基金Key Project of State Science and Technology during the tenth Five-year Plan (2001BA601B01-01-05).
文摘In the paper, we use the Central Moment Tensor (CMT) solution acquired by Harvard Univ. for the earthquakes occurred in Kurile Islands to analyze the consistent focal mechanism in the area and propose the idea of making earthquake prediction based on the consistent parameter a of focal mechanism and stress field. The results from the study indicate that before Mw greater than or equal 7.5 earthquakes, the consistent parameter a decreases, which starts about 10-110 days and ends about 30-2 days before the great earthquakes. Although the phenomenon is not totally the same for individual earthquake, the difference is not large. Certainly, the phenomenon should be tested by time for its reliability. However, it should not be random that the focal mechanism of Mw greater than or equal 5.3 earthquakes are consistent successively with the stress field in an area of several hundreds kilometers in length. It should be a phenomenon of predictive significance. When the accumulated earthquake examples are sufficient, uniform judgment criteria and prediction principles can be stipulated then.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFC1505602)the National Natural Science Foundation of China(Grant Nos.41705055 and 41505088)+2 种基金the Project of Scientific Creation of Post-Graduates of Jiangsu(Grant No.CXZZ12_0485)the Creative Teams of Jiangsu Qinglan Projectthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Correlation-coefficient fields are widely used in short-term climate prediction research. The most frequently used significance test method for the correlation-coefficient field was proposed by Livezey, in which the number of significantcorrelation lattice(station) points on the correlation coherence map is used as the statistic. However, the method is based on two assumptions:(1) the spatial distribution of the lattice(station) points is uniform;and(2) there is no correlation between the physical quantities in the correlation-coefficient field. However, in reality, the above two assumptions are not valid.Therefore, we designed a more reasonable method for significance testing of the correlation-coefficient field. Specifically, a new statistic, the significant-correlation area, is introduced to eliminate the inhomogeneity of the grid(station)-point distribution, and an empirical Monte Carlo method is employed to eliminate the spatial correlation of the matrix.Subsequently, the new significance test was used for simultaneous correlation-coefficient fields between intensities of the atmospheric activity center in the Northern Hemisphere and temperature/precipitation in China. The results show that the new method is more reasonable than the Livezey method.
基金financially supported by Chinese National Basic Research 973 Program(2014CB440803)the National Natural Science Foundation of China(41572077)China Geological Survey Bureau(12120114065801,121201001000150010 and 121201004000150017-43)
文摘1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et al.,2006).The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south.
基金Project supported by the Sinopec Ministry of Science and Technology Project “Fine Modeling and Production Stabilization Strategy by Water Control for Reef-Flat Facies Gas Reservoir” (No.: P15050).
文摘Study on the effectiveness of fractures is of great significance for understanding reservoir types and properties, identifying reservoir seepage mechanisms and delineating the reasonable development technologies and policies. In this paper, the Changxing reef-flat facies reservoirs in the Yuanba area, Sichuan Basin, was taken as an example. After the characteristics of natural fractures were evaluated, the effectiveness of different types of fractures was investigated by using core, thin section, imaging logging and production performance data. Then, the main geological factors that influence fracture effectiveness were analyzed, and the development significance of effective fractures was illustrated. The following results are obtained. (1) Structural fractures and diagenetic fractures are mainly developed in Changxing Fm carbonate reservoirs in Yuanba area. Structural fractures include shear fractures and extensional fractures, and diagenetic fractures include dissolution fractures, structural-dissolution fractures and pressure-solution fractures. (2) High-angle structural fractures are the most effective, followed by horizontal fractures and then oblique fractures, and pressure-solution fractures are the least effective. (3) Among structural fractures, those of NW–SE and nearly E–W oriented are more effective than those of the NE–SW oriented. (4) The earlier the fractures are formed, the more likely they are to be filled with calcite or dolomite and become invalid. (5) The fractures which are formed before or during the oil and gas charging tend to be filled with organic matters and become invalid. The late fractures which are formed after oil and gas charging are mostly effective and their contribution to the reservoir is the greatest. (6) The fractures nearly parallel to the maximum principal stress direction of current ground stress present good effectiveness with large opening. It is concluded that the opening and filling features of natural fractures help determine if fractures are effective or not, and the development degree, distribution and combination features of effective fractures and the matching relationship between fractures and pores further dominate the development significance of effective fractures;that when the effective fractures are more developed and are connected with each other to form a large-scale fracture network, separated and isolated pores and dissolved fractures and cavities can be connected, as a result, the physical properties of reservoirs are improved and high production rates of gas wells are realized.
