Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the ...Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.展开更多
Based on 3D seismic data, the evolution mechanism and characteristics of faults were investigated to reveal the structural origin and its control on differential hydrocarbon accumulation through comprehensive analyses...Based on 3D seismic data, the evolution mechanism and characteristics of faults were investigated to reveal the structural origin and its control on differential hydrocarbon accumulation through comprehensive analyses, including structure style analysis, fault activity analysis, analogue modelling and comparison among the wells. The complex fault system with differently trending faults resulted from strike-slip and rifting in Paleogene was partly activated, developed successively and stretched obliquely by the near-NS extensional stress field in Neogene. In the area little affected by pre-existing faults, new faults nearly perpendicular to the extension direction developed. The structural development in the study area was not caused by transpressional strike slip. Under the oblique extension effect of pre-existing faults, if the angle between the strike of pre-existing fault and the extensional direction is different, the strike-slip and extensional stresses are different in ratio. The larger the angle between the two is, the stronger the extensional component, the poorer the sealing ability of the fault, and the stronger the oil and gas migration capacity will be. Conversely, the smaller the angle between the two is, the stronger the strike-slip component, the better the sealing ability of the fault, and the poorer the oil and gas migration capacity will be. The accumulation condition analysis results considering the fault trend are in good agreement with the oil and gas shows in wells drilled in this area.展开更多
The kinematic characteristics of the Sanguankou-Niushoushan fault（SGK-NSSF） are of great significance to the understanding of the extension of the arc tectonic belt in the northeastern margin of the Tibet Plateau. U...The kinematic characteristics of the Sanguankou-Niushoushan fault（SGK-NSSF） are of great significance to the understanding of the extension of the arc tectonic belt in the northeastern margin of the Tibet Plateau. Using field surveys and various data collection methods, including large-scale geological mapping, measurement of typical topographies, and dating of sedimentary strata, it was determined that the SGK-NSSF exhibits obvious dextral strike-slip characteristics and thus is not a sinistral strike-slip fault, as believed by previous researchers. The results of this study show that the geological boundaries for the Paleozoic, Mesozoic, and Cenozoic eras were all dextrally dislocated by the fault, with the faulted displacements being similar. The maximum strike-slip displacement of the fault, after elimination of topographic effects, was found to be 961±6 m. The Sanguankou fault at the northern section exhibits obvious characteristics of more recent activities, with a series of small gullies having undergone synchronized dextral writhing after traversing the fault. The average horizontal slip rate of the fault since the late Quaternary was determined to be approximately 0.35 mm/a. The pre-existing fold structures formed during the late Pliocene were dislocated by the fault and became ex situ, indicating that dextral strike-slip of the fault could not have occurred prior to the late Pliocene. The maximum displacements and average slip rates were used to estimate the onset time of the dextral strike-slip activities of the fault as being after 2.7 Ma. In this study, the understanding of previous researchers concerning the extension in the northeastern margin of the Tibet Plateau was combined with analyses of the successive relationships between fold deformations and fault activities. This led to the finding that the extension in the northeastern margin of the Tibet Plateau reached the vicinity of the SGK-NSSF during the late Pliocene（~2.7 Ma）, causing regional uplift and fold deformations of the strata there. During the early Quaternary, the northeastern compression of the Tibet Plateau and the counterclockwise rotation of the Ordos block collectively resulted in the dextral strike-slip activities of the SGK-NSSF. This then formed the foremost margin of the arc tectonic belt extension in the northeastern margin of the Tibet Plateau.展开更多
The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,no...The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,none of these models has been universally accepted because they do not fully match a large number of geological phenomena and facts.By examining the regional tectonics and integrating them with measured data for the SCS,in this study,a back-arc spreading-sinistral shear model is proposed.It is suggested that the SCS is a back-arc basin formed by northward subduction of the PSCS and its formation was triggered by left-lateral strike-slip motion due to the northward drift of the Philippine Sea Plate.The left-lateral strike-slip fault on the western margin caused by the Indo-Eurasian collision changed the direction of the Southwest Sub-basin's spreading axis from nearly E–W to NE–SW,and subduction retreat caused the spreading ridge to jump southward.This study summarizes the evolution of the SCS and adjacent regions since the Late Mesozoic.展开更多
Saravan Fault is the biggest fault in southeast of Iran. It is Right-Slip fault. It has been extended from northwest to southeast. It is important to evaluate tectonic activities along this fault because it is adjacen...Saravan Fault is the biggest fault in southeast of Iran. It is Right-Slip fault. It has been extended from northwest to southeast. It is important to evaluate tectonic activities along this fault because it is adjacent to the city and various villages. It’s found that there are various tectonic activities along this fault. In this paper, it has been studied on affecting this fault on geomorphology of the zone. Average values of some indices such as Mountain Font Sinuosity and V ratio have been studied that they are 1.76 and 0.77, respectively. It suggests that there are serious tectonic activities in the zone. There are some evidences such as Right-Slip fault along artificial river channel that indicates its youngest stage means Late Cenozoic. According to studies, Saravan Fault is more active in the middle zone than northwest and southeast ends.展开更多
Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in th...Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in the northern Tibetan Plateau. We present Late Cretaceous dextral movement affected by Okhotomorsk Block-East Asia collision and a larger sinistral offset since Late Eocene along the ATF based on the provenance analysis of western Jiuxi Basin. Moreover, currently available estimates of offset based on displaced Paleozoic and Jurassic rocks could not represent the maximum offset due to late Cretaceous dextral offset.展开更多
The Linglong-Jiaojia ore-centralized district is controlled by the tectonic stress field characterized by the combination of extension and strike-slip, and the dip, dip angle, pitch and pitch angle of the ore bodies a...The Linglong-Jiaojia ore-centralized district is controlled by the tectonic stress field characterized by the combination of extension and strike-slip, and the dip, dip angle, pitch and pitch angle of the ore bodies are all constrained by the dynamic conditions of the tectonics. The metallotectonic series for the ore-centralized district belong to the type of a combination of extension and strike-slip and can be subdivided into four sub-series. The ore-forming process in the brittle regime can be disintegrated into two stages, i.e., the embryonic fracture stage and the megascopic fracture stage, and ore-forming process is rather common in the ore-centralized district at the former stage. Moreover, several key structural patterns and their features were discussed and a preliminary assessment about the ore-forming prospect in this district was made in the paper.展开更多
The model about block extrusion related to collision between Eurasia and India which is proposed by Tapponnier et al. has not been accepted so far in the field. Based on kinematics and chronology, the Gailigong dextra...The model about block extrusion related to collision between Eurasia and India which is proposed by Tapponnier et al. has not been accepted so far in the field. Based on kinematics and chronology, the Gailigong dextral strike-slip fault in west Yunnan and Nabang dextral strike-slip fault which is the part of Mogok belt are the western boundary of extrusion blocks, as the eastern boundary Red River-Ailaoshan left-lateral fault. And more studies show that as the important way for absorbing the convergence between two continents, the age of blocks’ multistage extrusion is about 23 and 13 Ma.展开更多
文摘Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.
基金Supported by the China National Science and Technology Major Project(2016ZX05024-002-006)
文摘Based on 3D seismic data, the evolution mechanism and characteristics of faults were investigated to reveal the structural origin and its control on differential hydrocarbon accumulation through comprehensive analyses, including structure style analysis, fault activity analysis, analogue modelling and comparison among the wells. The complex fault system with differently trending faults resulted from strike-slip and rifting in Paleogene was partly activated, developed successively and stretched obliquely by the near-NS extensional stress field in Neogene. In the area little affected by pre-existing faults, new faults nearly perpendicular to the extension direction developed. The structural development in the study area was not caused by transpressional strike slip. Under the oblique extension effect of pre-existing faults, if the angle between the strike of pre-existing fault and the extensional direction is different, the strike-slip and extensional stresses are different in ratio. The larger the angle between the two is, the stronger the extensional component, the poorer the sealing ability of the fault, and the stronger the oil and gas migration capacity will be. Conversely, the smaller the angle between the two is, the stronger the strike-slip component, the better the sealing ability of the fault, and the poorer the oil and gas migration capacity will be. The accumulation condition analysis results considering the fault trend are in good agreement with the oil and gas shows in wells drilled in this area.
基金supported by the Fundamental Research Funds in Institute of Geology, China Earthquake Administration (Grant No. IGCEA1220)Special Project on Earthquake Research (Grant No. 201308012)+1 种基金National Natural Science Foundation of China (Grant Nos. 41202158, 41372220 & 41590861)Science for Earthquake Resilience (Grant No. XH14052)
文摘The kinematic characteristics of the Sanguankou-Niushoushan fault（SGK-NSSF） are of great significance to the understanding of the extension of the arc tectonic belt in the northeastern margin of the Tibet Plateau. Using field surveys and various data collection methods, including large-scale geological mapping, measurement of typical topographies, and dating of sedimentary strata, it was determined that the SGK-NSSF exhibits obvious dextral strike-slip characteristics and thus is not a sinistral strike-slip fault, as believed by previous researchers. The results of this study show that the geological boundaries for the Paleozoic, Mesozoic, and Cenozoic eras were all dextrally dislocated by the fault, with the faulted displacements being similar. The maximum strike-slip displacement of the fault, after elimination of topographic effects, was found to be 961±6 m. The Sanguankou fault at the northern section exhibits obvious characteristics of more recent activities, with a series of small gullies having undergone synchronized dextral writhing after traversing the fault. The average horizontal slip rate of the fault since the late Quaternary was determined to be approximately 0.35 mm/a. The pre-existing fold structures formed during the late Pliocene were dislocated by the fault and became ex situ, indicating that dextral strike-slip of the fault could not have occurred prior to the late Pliocene. The maximum displacements and average slip rates were used to estimate the onset time of the dextral strike-slip activities of the fault as being after 2.7 Ma. In this study, the understanding of previous researchers concerning the extension in the northeastern margin of the Tibet Plateau was combined with analyses of the successive relationships between fold deformations and fault activities. This led to the finding that the extension in the northeastern margin of the Tibet Plateau reached the vicinity of the SGK-NSSF during the late Pliocene（~2.7 Ma）, causing regional uplift and fold deformations of the strata there. During the early Quaternary, the northeastern compression of the Tibet Plateau and the counterclockwise rotation of the Ordos block collectively resulted in the dextral strike-slip activities of the SGK-NSSF. This then formed the foremost margin of the arc tectonic belt extension in the northeastern margin of the Tibet Plateau.
基金funded by the projects of the China Geological Survey(DD20160138,GZH201300502,DD20190378)the Major Special Project for talent team introduction of the Southern Marine Science and Engineering Guang Dong Laboratory(Guang Zhou)(GML2019ZD0207)。
文摘The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,none of these models has been universally accepted because they do not fully match a large number of geological phenomena and facts.By examining the regional tectonics and integrating them with measured data for the SCS,in this study,a back-arc spreading-sinistral shear model is proposed.It is suggested that the SCS is a back-arc basin formed by northward subduction of the PSCS and its formation was triggered by left-lateral strike-slip motion due to the northward drift of the Philippine Sea Plate.The left-lateral strike-slip fault on the western margin caused by the Indo-Eurasian collision changed the direction of the Southwest Sub-basin's spreading axis from nearly E–W to NE–SW,and subduction retreat caused the spreading ridge to jump southward.This study summarizes the evolution of the SCS and adjacent regions since the Late Mesozoic.
文摘Saravan Fault is the biggest fault in southeast of Iran. It is Right-Slip fault. It has been extended from northwest to southeast. It is important to evaluate tectonic activities along this fault because it is adjacent to the city and various villages. It’s found that there are various tectonic activities along this fault. In this paper, it has been studied on affecting this fault on geomorphology of the zone. Average values of some indices such as Mountain Font Sinuosity and V ratio have been studied that they are 1.76 and 0.77, respectively. It suggests that there are serious tectonic activities in the zone. There are some evidences such as Right-Slip fault along artificial river channel that indicates its youngest stage means Late Cenozoic. According to studies, Saravan Fault is more active in the middle zone than northwest and southeast ends.
文摘Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in the northern Tibetan Plateau. We present Late Cretaceous dextral movement affected by Okhotomorsk Block-East Asia collision and a larger sinistral offset since Late Eocene along the ATF based on the provenance analysis of western Jiuxi Basin. Moreover, currently available estimates of offset based on displaced Paleozoic and Jurassic rocks could not represent the maximum offset due to late Cretaceous dextral offset.
基金supported by China National Science Foundation Grant No.40072022CAS Knowledge Innovation Project No.KZCX2-SW-1l7
文摘The Linglong-Jiaojia ore-centralized district is controlled by the tectonic stress field characterized by the combination of extension and strike-slip, and the dip, dip angle, pitch and pitch angle of the ore bodies are all constrained by the dynamic conditions of the tectonics. The metallotectonic series for the ore-centralized district belong to the type of a combination of extension and strike-slip and can be subdivided into four sub-series. The ore-forming process in the brittle regime can be disintegrated into two stages, i.e., the embryonic fracture stage and the megascopic fracture stage, and ore-forming process is rather common in the ore-centralized district at the former stage. Moreover, several key structural patterns and their features were discussed and a preliminary assessment about the ore-forming prospect in this district was made in the paper.
文摘The model about block extrusion related to collision between Eurasia and India which is proposed by Tapponnier et al. has not been accepted so far in the field. Based on kinematics and chronology, the Gailigong dextral strike-slip fault in west Yunnan and Nabang dextral strike-slip fault which is the part of Mogok belt are the western boundary of extrusion blocks, as the eastern boundary Red River-Ailaoshan left-lateral fault. And more studies show that as the important way for absorbing the convergence between two continents, the age of blocks’ multistage extrusion is about 23 and 13 Ma.
