The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,befor...The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,before and after the ocean–continental conversion in Late Paleozoic.The later on intracontinental deformation,characterized by the development of the NE-trending West Junggar sinistral strike-slip fault system(WJFS)since Late Carboniferous and Early Permian,and the NW-trending Chingiz-Junggar dextral strike-slip fault(CJF)in Mesozoic and Cenozoic,has an important significance for the tectonic evolution of the WJOB and the CAOB.In this paper,we conduct geometric and kinematic analyses of the WJOB,based on field geological survey and structural interpretation of remote sensing image data.Using some piercing points such as truncated plutons and anticlines,an average magnitude of^73 km for the left-lateral strike-slip is calculated for the Darabut Fault,a major fault of the WJFS.Some partial of the displacement should be accommodated by strike-slip fault-related folds developed during the strike-slip faulting.Circular and curved faults,asymmetrical folds,and irregular contribution of ultramafic bodies,implies potential opposite vertical rotation of the Miao’ergou and the Akebasitao batholiths,resulted from the sinistral strike-slipping along the Darabut Fault.Due to conjugate shearing set of the sinistral WJFS and the dextral CJF since Early Mesozoic,superimposed folds formed with N–S convergence in southwestern part of the WJOB.展开更多
Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-...Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-August from 1951 to 2006, and focusing on the East Asia-West Pacific region （10°-80°N, 70°-180°E）, interannual variation of East Asian summer monsoon （EASM） and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function （EOF） analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows： （1） EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal dipole oscillation mode （APD） between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. （2） EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern （EAP）, and EAP index can also be used as an EASM intensity index. （3） The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa （or 850 hPa）. The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of -0.23, which passes the confidence test at 0.10 level. （4） Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.展开更多
基金supported by the China Geological Survey (Grant Nos. DD20160083, DD20160344-05)the Chinese Academy of Geological Sciences Research Fund (Grant No. CAGS-YWF201706)
文摘The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,before and after the ocean–continental conversion in Late Paleozoic.The later on intracontinental deformation,characterized by the development of the NE-trending West Junggar sinistral strike-slip fault system(WJFS)since Late Carboniferous and Early Permian,and the NW-trending Chingiz-Junggar dextral strike-slip fault(CJF)in Mesozoic and Cenozoic,has an important significance for the tectonic evolution of the WJOB and the CAOB.In this paper,we conduct geometric and kinematic analyses of the WJOB,based on field geological survey and structural interpretation of remote sensing image data.Using some piercing points such as truncated plutons and anticlines,an average magnitude of^73 km for the left-lateral strike-slip is calculated for the Darabut Fault,a major fault of the WJFS.Some partial of the displacement should be accommodated by strike-slip fault-related folds developed during the strike-slip faulting.Circular and curved faults,asymmetrical folds,and irregular contribution of ultramafic bodies,implies potential opposite vertical rotation of the Miao’ergou and the Akebasitao batholiths,resulted from the sinistral strike-slipping along the Darabut Fault.Due to conjugate shearing set of the sinistral WJFS and the dextral CJF since Early Mesozoic,superimposed folds formed with N–S convergence in southwestern part of the WJOB.
基金funded by the Ministry of Science and Technology of the People’s Republic of China,No.2007DFB20210National Natural Science Foundation of China,No.90502003JICA China-Japan Technical Cooperative Project "China-Japanese Cooperative Research Center on Meteorological Disasters"
文摘Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-August from 1951 to 2006, and focusing on the East Asia-West Pacific region （10°-80°N, 70°-180°E）, interannual variation of East Asian summer monsoon （EASM） and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function （EOF） analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows： （1） EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal dipole oscillation mode （APD） between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. （2） EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern （EAP）, and EAP index can also be used as an EASM intensity index. （3） The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa （or 850 hPa）. The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of -0.23, which passes the confidence test at 0.10 level. （4） Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.
