<div style="text-align:justify;"> Based on the detailed interpretation of high-accuracy 3D seismic data, the characteristics of regional unconformities, fracture systems, sedimentary filling and paleo-...<div style="text-align:justify;"> Based on the detailed interpretation of high-accuracy 3D seismic data, the characteristics of regional unconformities, fracture systems, sedimentary filling and paleo-stress field in Zhu 1 depression were comprehensively analyzed. The results showed that 2nd episode of Zhu-Qiong movement was an important tectonic transformation that occurred during rifting, basin structure patterns above and below the regional angular unconformity caused by 2nd episode had distinct differences. The orientations of those basin-controlling faults changed from NE, NEE to EW, NWW, which indicated that the paleo-stress field veered from NNW extension clockwise to sub-NS extension and basin structures patterns transformed from NE, NEE strong rifting to sub-EW, NWW weak rifting. The depocenter showed seesaw-like migration from S to N. And the sedimentary systems transformed from semi-deep-deep lacustrine facies to braided river delta facies developed in shore-shallow lacustrine. Combined with its tectonic recombination of periphery plates that period, the mechanism of above tectonic transformation had direct correspondence to the readjustment of the Indian plate and the Pacific plate. The southward subduction of the pro-to-south China Sea is the direct cause of this tectonic transformation. </div>展开更多
Since the Mesozoic and Cenozoic, a transformation from a Tethyan Himalayan tectonic domain into a circum Pacific tectonic domain from Indosinian to Yanshanian is indicated in this paper, resulting in conspicuous cha...Since the Mesozoic and Cenozoic, a transformation from a Tethyan Himalayan tectonic domain into a circum Pacific tectonic domain from Indosinian to Yanshanian is indicated in this paper, resulting in conspicuous changes in geophysics, tectono magmatic distribution, lithofacies and paleo geography, tectonic system in southeastern China. Tectonic analysis shows that the tectonic framework resulted from the compounding, transforming and superimposing of the two tectonic domains. The geodynamic mechanism of the transformation is mainly shown as the transverse and longitudinal heterogeneity of lithosphere, and the exchange between the crust and the mantle.展开更多
The Late Paleozoic volcanic rocks are widespread in the Western Tianshan,and mainly consist of basalt,trachyte,trachy-andesite,andesite and rhyolite.However,the formation timing and tectonic implications of the volcan...The Late Paleozoic volcanic rocks are widespread in the Western Tianshan,and mainly consist of basalt,trachyte,trachy-andesite,andesite and rhyolite.However,the formation timing and tectonic implications of the volcanic rocks remain controversial.To obtain a comprehensive dataset with adequate spatial coverage,we collected the published zircon U-Pb age data of the Late Paleozoic volcanic rocks in the Western Tianshan,and mapped the temporal and spatial distribution of these volcanic rocks.Our compiled dataset indicates that the volcanic rocks in the Western Tianshan were formed in two major stages:Late Silurian-Early Carboniferous and Late Carboniferous-Middle Permian.The southward subduction of the Northern Tianshan Ocean formed a large number of Late Silurian-Early Carboniferous volcanic rocks.The flare-up of Late Carboniferous to Middle Permian magmatism in the NTOB was considered to be the response of the slab-roll back of the northern Tianshan Ocean.Therefore,arc magma assemblage and spatial-temporal distribution are of great significance to identify the dynamic mechanism transformation of subduction zone.展开更多
The Suoerkuduke Cu （Mo） deposit, in the same metallogenic belt with Xilekuduke Cu-Mo deposit, is located in the Armantai island arc belt on the northern margin of East Junggar, Northwest China. Rhenium and osmium is...The Suoerkuduke Cu （Mo） deposit, in the same metallogenic belt with Xilekuduke Cu-Mo deposit, is located in the Armantai island arc belt on the northern margin of East Junggar, Northwest China. Rhenium and osmium isotopic analysis of seven molybdenite samples from the deposit was used to determine the age of mineralization. A seven-point isochron age of 317.7±7.6 Ma, which is consistent, within analytical error, with the average model age of 323.3±1.9 Ma indicates that this deposit was formed at transitional period between the Early and Late Carboniferous. This age is obviously later than that of the Lower Devonian Tuoranggekuduke Formation acting as the wall rock but contemporaneous with the early stage of plutonism （330-268 Ma） in East Junggar. Based on the characteristics of mineralization age and tectonic setting of many typical deposits on the northern margin of East Junggar, we proposed that the mineralization age of Suoerkuduke deposit is a key period of East Junggar for the tectonic regime transforming from compression to extension and also the time when granitoids and deposits widely spread in this area. Mineralization and formation of skarn in this deposit are closely related to felsic-intermediate magmatism. The distinct characteristic from typical skarn-type deposits is that the metallogenic parent intrusion is a huge batholith in the depth. The Cu （Mo） mineralization, moyitc, and granite porphyry are all derived products of the batholith.展开更多
As a result of the left-lateral strike-slipping of the Altyn Tagh fault in Neotectonic period,a contra-rotational structure,namely the Zhaobishan vortex structure,has developed at the juncture of the main Altyn Tagh f...As a result of the left-lateral strike-slipping of the Altyn Tagh fault in Neotectonic period,a contra-rotational structure,namely the Zhaobishan vortex structure,has developed at the juncture of the main Altyn Tagh fault and the northern fringe fault of the Qilian Mountains.Preliminary analysis on the deformation and evolution of the Zhaobishan vortex structure.In combination with the previous data,suggests that the tectonic transform between the Altyn Tagh fault and the northern fringe fault of the Qilian Mountains attributes to the deformation of the rotational structure.The existence of a series of rotational structures along the Altyn Tagh fault and on the northeastern edge of the Qinghai-Xizang(Tibet)plateau indicate that as the substance in the northern Qinghai-Xizang(Tibet)plateau moves clockwise around the eastern tectonic knot of the Himalayas,rotational structures become the principal mode on the northern marginal zone of the Plateau of transforming and absorbing tectonic deformation.展开更多
Two types of the Jurassic basins are distinguished in SE China based on their geodynamic features: the Late Triassic-Early Jurassic post-orogenic basins and the Middle Jurassic intra-continental extensional basins. Th...Two types of the Jurassic basins are distinguished in SE China based on their geodynamic features: the Late Triassic-Early Jurassic post-orogenic basins and the Middle Jurassic intra-continental extensional basins. The Lower Jurassic sequence shows a change from coarseto fine-grained accumulation, suggesting a gradually deepening depositional environment from river to shore-lake and to deep-water lake. In contrast, the Middle Jurassic accumulation was changed from claystone to conglomerate along the coastal provinces in SE China, indicative of an initial crustal uplift. The Wuyi Mountains have been a paleogeograghic separating zone since the Middle Jurassic. The Late Jurassic strata are absent in most areas of SE China. A large-scale bimodal intra-continental rift-type volcanism occurred during the Middle Jurassic along a 40-60 km wide and 200 km long area in western Fujian and southern Jiangxi provinces, which is most likely the strongest volcanism in SE China since the Cambrian. The SHRIMP zircon U-Pb analyses on the rhyolite from the Dongkeng basin in the southern Jiangxi area yield a concord U-Pb age of 160±0.5 Ma, providing an upper age limit for the bimodal volcanic eruption. The analyses of the basin features indicate a change of the depositional environment during the interval from Middle Triassic to Late Triassic from a shallow-sea to an intra-continent in SE China in response to the strong collision between the Yangtze and North China Blocks. Sedimentary structures record a southward direction of Early Jurassic paleo-currents, reflecting that their source areas were to the north side. We propose that the Wuyi region was uplifted as early as Middle Jurassic, followed by a wide E-W-trending extended depression and bimodal volcanism in the western foot of the Wuyi Mountains. Presumably the uplift of the Wuyi domain changed the Middle Jurassic paleo geographic outline and formed the transformational tectonic regime from compression to extension as a tectonic response to the Pacific plate subduction.展开更多
The nearly EW-trending East Kunlun fault zone is the north boundary of the Bayan Har block.The activity characteristics and the position of the eastern end of its eastward extension are of great significance to probin...The nearly EW-trending East Kunlun fault zone is the north boundary of the Bayan Har block.The activity characteristics and the position of the eastern end of its eastward extension are of great significance to probing into the dynamic mechanism of formation of the east edge of the Tibetan Plateau,and also lay the foundation for seismic risk assessment of the fault zone.The following results are obtained by analysis based on satellite image interpretation of landforms,surface rupture survey,terrace scarp deformation survey,and terrace dating data on the eastern part of the East Kunlun fault zone:(1)the Luocha segment is a Holocene active fault,where a reverse L-shape paleoearthquake surface rupture zone of about 50 km long is located;(2)the Luocha segment is characterized by left-lateral slip movement under the compression-shear condition since the later period of the Late Pleistocene,with a rate of 7.68–9.37 mm/a and a vertical slip rate of 0.7–0.9 mm/a,which are basically in accord with the activity rate of segments on its west side.The results indicate that it is a part of eastward extension of the East Kunlun fault zone;(3)the high-speed linear horizontal slip of the nearly EW-trending East Kunlun fault zone is blocked by the South China block at east,and transforms into the vertical movement of the nearly SN-NNE trending Minjiang fault zone and the Longmenshan fault zone,and the uplift of Longmenshan and Minjiang.The area where transform of the two tectonic systems occurred confines the position of the east end;(4)Luocha segment and Maqu segment constitute the"Maqu seismic gap",so,seismic risk at Maqu segment is higher than that at Luocha segment,which should attract more attention.展开更多
文摘<div style="text-align:justify;"> Based on the detailed interpretation of high-accuracy 3D seismic data, the characteristics of regional unconformities, fracture systems, sedimentary filling and paleo-stress field in Zhu 1 depression were comprehensively analyzed. The results showed that 2nd episode of Zhu-Qiong movement was an important tectonic transformation that occurred during rifting, basin structure patterns above and below the regional angular unconformity caused by 2nd episode had distinct differences. The orientations of those basin-controlling faults changed from NE, NEE to EW, NWW, which indicated that the paleo-stress field veered from NNW extension clockwise to sub-NS extension and basin structures patterns transformed from NE, NEE strong rifting to sub-EW, NWW weak rifting. The depocenter showed seesaw-like migration from S to N. And the sedimentary systems transformed from semi-deep-deep lacustrine facies to braided river delta facies developed in shore-shallow lacustrine. Combined with its tectonic recombination of periphery plates that period, the mechanism of above tectonic transformation had direct correspondence to the readjustment of the Indian plate and the Pacific plate. The southward subduction of the pro-to-south China Sea is the direct cause of this tectonic transformation. </div>
基金This study is financially supported by the Science and Technology Prospecting Project of the National Planning CommissionDire
文摘Since the Mesozoic and Cenozoic, a transformation from a Tethyan Himalayan tectonic domain into a circum Pacific tectonic domain from Indosinian to Yanshanian is indicated in this paper, resulting in conspicuous changes in geophysics, tectono magmatic distribution, lithofacies and paleo geography, tectonic system in southeastern China. Tectonic analysis shows that the tectonic framework resulted from the compounding, transforming and superimposing of the two tectonic domains. The geodynamic mechanism of the transformation is mainly shown as the transverse and longitudinal heterogeneity of lithosphere, and the exchange between the crust and the mantle.
基金supported by the National Key Research and Development Project (No.2019YFA0708601)the National Natural Science Foundation of China (Nos.41573045,41873060,and 41830216)+1 种基金the China Geological Survey (No.DD20221649)the Fund from the Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources (No.J1901-5)
文摘The Late Paleozoic volcanic rocks are widespread in the Western Tianshan,and mainly consist of basalt,trachyte,trachy-andesite,andesite and rhyolite.However,the formation timing and tectonic implications of the volcanic rocks remain controversial.To obtain a comprehensive dataset with adequate spatial coverage,we collected the published zircon U-Pb age data of the Late Paleozoic volcanic rocks in the Western Tianshan,and mapped the temporal and spatial distribution of these volcanic rocks.Our compiled dataset indicates that the volcanic rocks in the Western Tianshan were formed in two major stages:Late Silurian-Early Carboniferous and Late Carboniferous-Middle Permian.The southward subduction of the Northern Tianshan Ocean formed a large number of Late Silurian-Early Carboniferous volcanic rocks.The flare-up of Late Carboniferous to Middle Permian magmatism in the NTOB was considered to be the response of the slab-roll back of the northern Tianshan Ocean.Therefore,arc magma assemblage and spatial-temporal distribution are of great significance to identify the dynamic mechanism transformation of subduction zone.
基金supported by the National Natural Science Foundation of China (Nos. 41273019,40972053)the Chinese State 973 Program (No. 2007CB411302)the Fund of Chinese Academy of Sciences (No. KZCX2-YW-JS109)
文摘The Suoerkuduke Cu （Mo） deposit, in the same metallogenic belt with Xilekuduke Cu-Mo deposit, is located in the Armantai island arc belt on the northern margin of East Junggar, Northwest China. Rhenium and osmium isotopic analysis of seven molybdenite samples from the deposit was used to determine the age of mineralization. A seven-point isochron age of 317.7±7.6 Ma, which is consistent, within analytical error, with the average model age of 323.3±1.9 Ma indicates that this deposit was formed at transitional period between the Early and Late Carboniferous. This age is obviously later than that of the Lower Devonian Tuoranggekuduke Formation acting as the wall rock but contemporaneous with the early stage of plutonism （330-268 Ma） in East Junggar. Based on the characteristics of mineralization age and tectonic setting of many typical deposits on the northern margin of East Junggar, we proposed that the mineralization age of Suoerkuduke deposit is a key period of East Junggar for the tectonic regime transforming from compression to extension and also the time when granitoids and deposits widely spread in this area. Mineralization and formation of skarn in this deposit are closely related to felsic-intermediate magmatism. The distinct characteristic from typical skarn-type deposits is that the metallogenic parent intrusion is a huge batholith in the depth. The Cu （Mo） mineralization, moyitc, and granite porphyry are all derived products of the batholith.
基金funded by the National Natural Sciences Foundation of China,Grant item number:40072058.
文摘As a result of the left-lateral strike-slipping of the Altyn Tagh fault in Neotectonic period,a contra-rotational structure,namely the Zhaobishan vortex structure,has developed at the juncture of the main Altyn Tagh fault and the northern fringe fault of the Qilian Mountains.Preliminary analysis on the deformation and evolution of the Zhaobishan vortex structure.In combination with the previous data,suggests that the tectonic transform between the Altyn Tagh fault and the northern fringe fault of the Qilian Mountains attributes to the deformation of the rotational structure.The existence of a series of rotational structures along the Altyn Tagh fault and on the northeastern edge of the Qinghai-Xizang(Tibet)plateau indicate that as the substance in the northern Qinghai-Xizang(Tibet)plateau moves clockwise around the eastern tectonic knot of the Himalayas,rotational structures become the principal mode on the northern marginal zone of the Plateau of transforming and absorbing tectonic deformation.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40634022, 40972132 and 40632010)the State Key Laboratory for Mineral Deposits Research (Nanjing University) (Grant No. 2008-I-01)
文摘Two types of the Jurassic basins are distinguished in SE China based on their geodynamic features: the Late Triassic-Early Jurassic post-orogenic basins and the Middle Jurassic intra-continental extensional basins. The Lower Jurassic sequence shows a change from coarseto fine-grained accumulation, suggesting a gradually deepening depositional environment from river to shore-lake and to deep-water lake. In contrast, the Middle Jurassic accumulation was changed from claystone to conglomerate along the coastal provinces in SE China, indicative of an initial crustal uplift. The Wuyi Mountains have been a paleogeograghic separating zone since the Middle Jurassic. The Late Jurassic strata are absent in most areas of SE China. A large-scale bimodal intra-continental rift-type volcanism occurred during the Middle Jurassic along a 40-60 km wide and 200 km long area in western Fujian and southern Jiangxi provinces, which is most likely the strongest volcanism in SE China since the Cambrian. The SHRIMP zircon U-Pb analyses on the rhyolite from the Dongkeng basin in the southern Jiangxi area yield a concord U-Pb age of 160±0.5 Ma, providing an upper age limit for the bimodal volcanic eruption. The analyses of the basin features indicate a change of the depositional environment during the interval from Middle Triassic to Late Triassic from a shallow-sea to an intra-continent in SE China in response to the strong collision between the Yangtze and North China Blocks. Sedimentary structures record a southward direction of Early Jurassic paleo-currents, reflecting that their source areas were to the north side. We propose that the Wuyi region was uplifted as early as Middle Jurassic, followed by a wide E-W-trending extended depression and bimodal volcanism in the western foot of the Wuyi Mountains. Presumably the uplift of the Wuyi domain changed the Middle Jurassic paleo geographic outline and formed the transformational tectonic regime from compression to extension as a tectonic response to the Pacific plate subduction.
基金supported by the Systematic Scientific Investigation of Yushu Earthquake(Grant No.02106601)National Key Basic Research Program of China(Grant No.2008CB42570)Basic Research Fund of Institute of Earthquake Science(Grant No.02092437)
文摘The nearly EW-trending East Kunlun fault zone is the north boundary of the Bayan Har block.The activity characteristics and the position of the eastern end of its eastward extension are of great significance to probing into the dynamic mechanism of formation of the east edge of the Tibetan Plateau,and also lay the foundation for seismic risk assessment of the fault zone.The following results are obtained by analysis based on satellite image interpretation of landforms,surface rupture survey,terrace scarp deformation survey,and terrace dating data on the eastern part of the East Kunlun fault zone:(1)the Luocha segment is a Holocene active fault,where a reverse L-shape paleoearthquake surface rupture zone of about 50 km long is located;(2)the Luocha segment is characterized by left-lateral slip movement under the compression-shear condition since the later period of the Late Pleistocene,with a rate of 7.68–9.37 mm/a and a vertical slip rate of 0.7–0.9 mm/a,which are basically in accord with the activity rate of segments on its west side.The results indicate that it is a part of eastward extension of the East Kunlun fault zone;(3)the high-speed linear horizontal slip of the nearly EW-trending East Kunlun fault zone is blocked by the South China block at east,and transforms into the vertical movement of the nearly SN-NNE trending Minjiang fault zone and the Longmenshan fault zone,and the uplift of Longmenshan and Minjiang.The area where transform of the two tectonic systems occurred confines the position of the east end;(4)Luocha segment and Maqu segment constitute the"Maqu seismic gap",so,seismic risk at Maqu segment is higher than that at Luocha segment,which should attract more attention.
