The Plio-Quaternary deformation pattern of the northern Aegean and south Balkan regions is interpreted as an effect of the interaction between the Anatolian-Aegean-Pelagonian system (Tethyan belt), undergoing westward...The Plio-Quaternary deformation pattern of the northern Aegean and south Balkan regions is interpreted as an effect of the interaction between the Anatolian-Aegean-Pelagonian system (Tethyan belt), undergoing westward extrusion and strong deformation, and the surrounding plates (Nubia, Europe and Adriatic). Since the middle-late Miocene, the collision of the Tethyan belt with the continental Adriatic domain has caused strong E-W shortening in the outer Hellenides and Albanides, also involving the southward extrusion of the Peloponnesus wedge, at the expense of the Ionian oceanic domain. The roughly E-W extension recognized in the western South Balkan zones (Macedonia and eastern Albania) is related to the divergence between the Pelagonian belt (Albanides and Hellenides) and the Rhodope-Moesia domain. Stressed by the westward displacement of the central Anatolian plateau and by the southward bowing of the Cycladic Arc, the northern Aegean zone has contemporaneously undergone E-W compression and N-S extension, which has generated a series of dextral shear faults, delimiting a number of slats. The westward displacement and deformation of such slats can explain the morphological features of the northern Aegean zone. During this phase, the push of the central Anatolian plateau also caused the separation of the Rhodope massif from the Moesian European domain, with the consequent formation of the upper Thrace basin. This hypothesis can explain the Plio-Quaternary compressional deformations recognized in a sector of the North Anatolian fault system, the Ganos-Gelibolu zone. The proposed geodynamic/tectonic interpretation may help to explain some features of the time-space distribution of major earthquakes in the study area.展开更多
Researches were made of different continental-margin and intraplate basin systems in the Qinling microplate in terms of hydrothermal deposition, geodynamics of basin formation, hydrothermal sedimentary rock facies, sy...Researches were made of different continental-margin and intraplate basin systems in the Qinling microplate in terms of hydrothermal deposition, geodynamics of basin formation, hydrothermal sedimentary rock facies, syntectonics in the basins, and the styles of ore accumulation in the basins.展开更多
Interest in the ore\|forming histories of basins has grown rapid since 1960 and is now intensive. The main reason behind the acceleration is the increasing awareness that the natural processes responsible for generati...Interest in the ore\|forming histories of basins has grown rapid since 1960 and is now intensive. The main reason behind the acceleration is the increasing awareness that the natural processes responsible for generating metal deposits in the sedimentary basin from the source rocks of the beneath the basin and intensively hydrothermal activity in the basin. Observations made in different continental margin basin systems and superlarge deposits in Chinese Yunnan\|Guizhou\|Guangxi Province on the eastern margin of the Qingzang (Himalaya—Karakoram—Tibet) were investigated in terms of geodynamics of basin formation. Geotectonically, the area is situated in the conjoint between the Tethys—Himalaya and the Marginal\|Pacific tectonic domain, characterized by very complex geological structure, typical basin\|mountain tectonics, abundant Superlarge deposits.展开更多
Tectonic deformation of Cenozoic strata,youthful tectonontorphology,and high seismicity in the western part of Sichuan and Yunnan(Southwest China)marked intensive tectonism there during the Ceno7oic.It is a good place...Tectonic deformation of Cenozoic strata,youthful tectonontorphology,and high seismicity in the western part of Sichuan and Yunnan(Southwest China)marked intensive tectonism there during the Ceno7oic.It is a good place for studying the continental geodynamics because it is far away from those active plate boundaries surrounding the East Asian continent but near the southeastern margin of the Qinghai-Xizang(Tibet)plateau.The present study discriminated two phases of tectonic deformation with quite different styles in Cenozoic.Early compression deformation,expressed by folds,thrust,and even nappe structure,mainly occurred between the middle and late Eocene.Late extension deformation expressed by block-faulting started at least in the late Pliocene.Nonconformity,absence of strata,nonsuccessive tectonism,and inverse movement of the faults in late stages illustrated that two different deformation phases should be caused by different geodynamic processes.The early compression deformation would be related to展开更多
Wugongshan in Jiangxi Province, China was a Mesozoic granitic dome type extensional tectonics that is composed of metamorphic core complexes, ductile and brittle shear deformed zones distributed around Mesozoic granit...Wugongshan in Jiangxi Province, China was a Mesozoic granitic dome type extensional tectonics that is composed of metamorphic core complexes, ductile and brittle shear deformed zones distributed around Mesozoic granites. Within it, the foliation defines an E W elliptical shape and bears S N stretching lineations. The axial part is located in Hongjiang Wanlongshan area and occupied by oriented granites with coaxial symmetric shear fabrics. The southern and northern flanks, including rocks in the Anfu Basin to the south and the Pingxiang Basin to the north, display top to south and top to north motions, respectively. The ductile and brittle structures indicate a geometric and kinematic consistency. The extensional tectonics is developed on a Caledonian metamorphic basement and is unconformably covered by Late Cretaceous red beds. Isotopic ages on muscovite, biotite and whole rock by 40 Ar 39 Ar, K Ar and Rb Sr suggest that the Wugongshan extensional doming began from the Triassic and ended in the Late Cretaceous. A geodynamic model is discussed.展开更多
Unlike most Precambrian cratons that have thick sub-continental lithospheric roots,the Archean lithosphere beneath the North China Craton is thin (reduced from 200 km to about 80 km),and has been replaced by a geochem...Unlike most Precambrian cratons that have thick sub-continental lithospheric roots,the Archean lithosphere beneath the North China Craton is thin (reduced from 200 km to about 80 km),and has been replaced by a geochemically juvenile lithospheric mantle.This is a unique regional geological event,which has attracted worldwide attention.In the North China Block,Late Mesozoic extensional tectonics is evident by low-angle detachment faults,syntectonic plutons bounded by ductile faults,metamorphic core complexes (MCC) and widespread Jurassic to Cretaceous half-grabens filled by continental terrigenous deposits and volcanic rocks.At a regional scale,these structures share the same NW-SE extensional direction,while maintaining their own individual kinematics.In other words,the MCC feature a top-to-the-NW sense of shear,and syntectonic plutons are typified by a top-to-the-SE shearing deformations.Geochronological results indicate that the extensional structures were formed between 130-120 Ma.These extensional events lead to magmatic rock emplacement,distributed at the footwall of the detachment faults.Two different exhumation stages can be identified based on regional structural and magmatic interpretation:a Jurassic slow or negligible exhumation and a Cretaceous fast one assisted by normal faulting.These two cooling stages correspond to distinct geodynamic processes that occurred during the Jurassic and Cretaceous.Extensional tectonics appear to have been insignificant before the Early Cretaceous,and the process may be demonstrated by partial melting of the crust.The second stage,dominated by an extensional regime,developed after ca 120 Ma,and is tentatively correlated with crustal extension caused by lithospheric removal of the North China Craton.展开更多
Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression
The Neo-Tethys Ocean was an eastward-gaping triangular oceanic embayment between Laurasia to the north and Gondwana to the south.The Neo-Tethys Ocean was initiated from the Early Permian with mircoblocks rifted from t...The Neo-Tethys Ocean was an eastward-gaping triangular oceanic embayment between Laurasia to the north and Gondwana to the south.The Neo-Tethys Ocean was initiated from the Early Permian with mircoblocks rifted from the northern margin of Gondwana.As the microblocks drifted northwards,the Neo-Tethys Ocean was expanded.Most of these microblocks collided with the Eurasia continent in the Late Triassic,leading to the final closure of the Paleo-Tethys Ocean,followed by oceanic subduction of the Neo-Tethys oceanic slab beneath the newly formed southern margin of the Eurasia continent.As the splitting of Gondwana continued,African-Arabian,Indian and Australian continents were separated from Gondwana and moved northwards at different rates.Collision of these blocks with the Eurasia continent occurred at different time during the Cenozoic,resulting in the closure of the Neo-Tethys Ocean and building of the most significant Alps-Zagros-Himalaya orogenic belt on Earth.The tectonic evolution of the Neo-Tethys Ocean shows different characteristics from west to east:Multi-oceanic basins expansion,bidirectional subduction and microblocks collision dominate in the Mediterranean region;northward oceanic subduction and diachronous continental collision along the Zagros suture occur in the Middle East;the Tibet and Southeast Asia are characterized by multi-block riftings from Gondwana and multi-stage collisions with the Eurasia continent.The negative buoyancy of subducting oceanic slabs can be considered as the main engine for northward drifting of Gondwana-derived blocks and subduction of the Neo-Tethys Ocean.Meanwhile,mantle convection and counterclockwise rotation of Gondwana-derived blocks and the Gondwana continent around an Euler pole in West Africa in non-free boundary conditions also controlled the evolution of the Neo-Tethys Ocean.展开更多
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 Pacif...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 tufts 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 geo- dynamical 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 exten- sional 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 tectonics between both shores of the Pacific, such as mantle plume formation, scales of extensional and igneous rock assemblages and the age of basin and range tectonics, were caused mainly by the Yellowstone mantle plume in the eastern shore of the Pacific.展开更多
The most prominent feature of the extensional tectonic framework of post high pressure (HP) and ultrahigh pressure (UHP) metamorphism in Dabieshan is the development of the multi layered extension detachment zones ...The most prominent feature of the extensional tectonic framework of post high pressure (HP) and ultrahigh pressure (UHP) metamorphism in Dabieshan is the development of the multi layered extension detachment zones surrounding the core of the Luotian dome, and the separation of the UHP, HP and epidote blueschist units by the detachment zones, which form the vertically stacking sheet like slices of the HP and UHP metamorphic rocks. From the core outwards, exist the HP and UHP rock barren Dabie complex, UHP unit, HP unit and epidote blueschist unit. The extension tectonics of post HP and UHP metamorphic event constrain the distribution and present configuration of the HP and UHP metamorphic rocks, and the extensional tectonic framework bears some similarities to the Cordillera metamorphic core complex. It is suggested that partial melting happened in the Dabie gneiss complex (DGC) and UHP unit contemporaneously with the extrusion of UHP metamorphic rocks into the lower-middle crust. The formation and emplacement of the migmatite and granites are the response to the change in thermal state, facilitating the transfer from the compressive regime to extensional regime in the crust. The large scale crustal extension and uplift and the accompanying anatexis in Dabieshan are probably related to the delamination and magmatic underplating in the mantle and the lower crust.展开更多
The Erlian fault basin group, a typical Basin and Range type fault basin group, was formed during Late Jurassic to Early Cretaceous, in which there are rich coal, oil and gas resources. In the present paper the abund...The Erlian fault basin group, a typical Basin and Range type fault basin group, was formed during Late Jurassic to Early Cretaceous, in which there are rich coal, oil and gas resources. In the present paper the abundant geological and petroleum information accumulated in process of industry oil and gas exploration and development of the Erlian basin group is comprehensively analyzed, the structures related to formation of basin are systematically studied, and the complete extensional tectonic system of this basin under conditions of wide rift setting and low extensional ratio is revealed by contrasting study with Basin and Range Province of the western America. Based on the above studies and achievements of the former workers, the deep background of the basin development is treated.展开更多
Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of...Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of NCC)during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma.展开更多
The relationship between deposition and tectonics of sedimentary basins has been a significant subject in recent years.Using typical rift basins such as the Nanpu Sag as an example,combined with the analysis of the te...The relationship between deposition and tectonics of sedimentary basins has been a significant subject in recent years.Using typical rift basins such as the Nanpu Sag as an example,combined with the analysis of the tectonics-palaeogeomorphology of basins,we undertook a detailed study of the differences of the third-order sequences in different basins,the combination of depositional systems within the sequence framework and the distribution of depocenters and subsidence centers.Our results revealed a significant relationship between the tectonics-palaeogeomorphology of rift basins and the filling styles of sedimentary sequences.The basin structure plays a primary role in controlling the development of the third-order sequences and the boundary of these sequences is easily formed in basins with gentle slopes,shallow water and a small area.The characteristics of the tectonics-palaeogeomorphology of rift basins are dominated by half-grabens of extensional faults,which affect the temporal and spatial combination of sedimentary systems within the sequences as well as the distribution of depocenters and subsidence centers.Based on the development rules of the faults dominating the half-grabens of extensional faults,rift basins are classified into two types: the single fault segmented-linkage type and the multi-fault combination type.The main controlling factors of the temporal and spatial combination of sedimentary systems and the distribution of depocenters and subsidence centers in different basins are different.The characteristics of early segmentation and later linkage of the faults play a critical role in controlling the sedimentary system combination within the sequence framework and the temporal and spatial differences of depocenters and subsidence centers of the single fault segmented-linkage rift basins,while the differences in fault activities are the dominating factors of the multi-fault combination rift basins.展开更多
During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where ...During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where the Early-Middle Jurassic intra-arc volcano-sedimentary Oseosan Volcanic Complex was developed on top of the Late Triassic-Early Jurassic post-collisional sequences, namely the Chungnam Basin. The basin shortening was accommodated mostly by contractional faults and related folds. In the basement, regional high-angle reverse faults as well as low-angle thrusts accommodate the overall shortening, and are compatible with those preserved in the cover. This suggests that their spatial and temporal development is strongly dependent on the initial basin geometry and inherited structures.Changes in transport direction observed along the basement-sedimentary cover interface is a characteristic structural feature, reflecting sequential kinematic evolution during basin inversion. Propagation of basement faults also enhanced shortening of the overlying sedimentary cover sequences. We constrain timing of the Late Jurassic-Early Cretaceous(ca. 158-110 Ma) inversion from altered K-feldspar 40 Ar/39 Ar ages in stacked thrust sheets and K-Ar illite ages of fault gouges, along with previously reported geochronological data from the area. This "non-magmatic phase" of the Daebo Orogeny is contemporaneous with the timing of magmatic quiescence across the Korean Peninsula. We propose the role of flat/low-angle subduction of the Paleo-Pacific Plate for the development of the "Laramide-style" basement-involved orogenic event along East Asian continental margin.展开更多
The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 5...The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 545-kmlong active-source ocean bottom seismometer(OBS)wide-angle reflection/refraction profile in the East China Sea.The P wave velocity model shows that the Moho depth rises significantly,from approximately 30 km in the East China Sea shelf to approximately 16 km in the axis of the Okinawa Trough.The lower crustal high-velocity zone(HVZ)in the southern Okinawa Trough,with V_(p) of 6.8-7.3 km/s,is a remarkable manifestation of the mantle material upwelling and accretion to the lower crust.This confirms that the lower crustal high-velocity mantle accretion is developed in the southern Okinawa Trough.During the process of back-arc extension,the crustal structure of the southern Okinawa Trough is completely invaded and penetrated by the upper mantle material in the axis region.In some areas of the southern central graben,the crust may has broken up and entered the initial stage of seafloor spreading.The discontinuous HVZs in the lower crust in the back-arc region also indicate the migration of spreading centers in the back-arc region since the Cenozoic.The asthenosphere material upwelling in the continent-ocean transition zone is constantly driving the lithosphere eastward for episodic extension,and is causing evident tectonic migration in the Western Pacific back-arc region.展开更多
文摘The Plio-Quaternary deformation pattern of the northern Aegean and south Balkan regions is interpreted as an effect of the interaction between the Anatolian-Aegean-Pelagonian system (Tethyan belt), undergoing westward extrusion and strong deformation, and the surrounding plates (Nubia, Europe and Adriatic). Since the middle-late Miocene, the collision of the Tethyan belt with the continental Adriatic domain has caused strong E-W shortening in the outer Hellenides and Albanides, also involving the southward extrusion of the Peloponnesus wedge, at the expense of the Ionian oceanic domain. The roughly E-W extension recognized in the western South Balkan zones (Macedonia and eastern Albania) is related to the divergence between the Pelagonian belt (Albanides and Hellenides) and the Rhodope-Moesia domain. Stressed by the westward displacement of the central Anatolian plateau and by the southward bowing of the Cycladic Arc, the northern Aegean zone has contemporaneously undergone E-W compression and N-S extension, which has generated a series of dextral shear faults, delimiting a number of slats. The westward displacement and deformation of such slats can explain the morphological features of the northern Aegean zone. During this phase, the push of the central Anatolian plateau also caused the separation of the Rhodope massif from the Moesian European domain, with the consequent formation of the upper Thrace basin. This hypothesis can explain the Plio-Quaternary compressional deformations recognized in a sector of the North Anatolian fault system, the Ganos-Gelibolu zone. The proposed geodynamic/tectonic interpretation may help to explain some features of the time-space distribution of major earthquakes in the study area.
基金The research was supported by the State Key Project onFoundation Research Planning(SKPFRP,grant G1999043200)the National Natural Science Foundation of China(NNSFC,No.48732080).
文摘Researches were made of different continental-margin and intraplate basin systems in the Qinling microplate in terms of hydrothermal deposition, geodynamics of basin formation, hydrothermal sedimentary rock facies, syntectonics in the basins, and the styles of ore accumulation in the basins.
文摘Interest in the ore\|forming histories of basins has grown rapid since 1960 and is now intensive. The main reason behind the acceleration is the increasing awareness that the natural processes responsible for generating metal deposits in the sedimentary basin from the source rocks of the beneath the basin and intensively hydrothermal activity in the basin. Observations made in different continental margin basin systems and superlarge deposits in Chinese Yunnan\|Guizhou\|Guangxi Province on the eastern margin of the Qingzang (Himalaya—Karakoram—Tibet) were investigated in terms of geodynamics of basin formation. Geotectonically, the area is situated in the conjoint between the Tethys—Himalaya and the Marginal\|Pacific tectonic domain, characterized by very complex geological structure, typical basin\|mountain tectonics, abundant Superlarge deposits.
文摘Tectonic deformation of Cenozoic strata,youthful tectonontorphology,and high seismicity in the western part of Sichuan and Yunnan(Southwest China)marked intensive tectonism there during the Ceno7oic.It is a good place for studying the continental geodynamics because it is far away from those active plate boundaries surrounding the East Asian continent but near the southeastern margin of the Qinghai-Xizang(Tibet)plateau.The present study discriminated two phases of tectonic deformation with quite different styles in Cenozoic.Early compression deformation,expressed by folds,thrust,and even nappe structure,mainly occurred between the middle and late Eocene.Late extension deformation expressed by block-faulting started at least in the late Pliocene.Nonconformity,absence of strata,nonsuccessive tectonism,and inverse movement of the faults in late stages illustrated that two different deformation phases should be caused by different geodynamic processes.The early compression deformation would be related to
文摘Wugongshan in Jiangxi Province, China was a Mesozoic granitic dome type extensional tectonics that is composed of metamorphic core complexes, ductile and brittle shear deformed zones distributed around Mesozoic granites. Within it, the foliation defines an E W elliptical shape and bears S N stretching lineations. The axial part is located in Hongjiang Wanlongshan area and occupied by oriented granites with coaxial symmetric shear fabrics. The southern and northern flanks, including rocks in the Anfu Basin to the south and the Pingxiang Basin to the north, display top to south and top to north motions, respectively. The ductile and brittle structures indicate a geometric and kinematic consistency. The extensional tectonics is developed on a Caledonian metamorphic basement and is unconformably covered by Late Cretaceous red beds. Isotopic ages on muscovite, biotite and whole rock by 40 Ar 39 Ar, K Ar and Rb Sr suggest that the Wugongshan extensional doming began from the Triassic and ended in the Late Cretaceous. A geodynamic model is discussed.
基金supported by the Innovative Project of the Chinese Academy of Sciences (Grant No. KZCX2-YW-Q05-05-03)the National Natural Science Foundation of China (Grants Nos. 90714007,40872142)
文摘Unlike most Precambrian cratons that have thick sub-continental lithospheric roots,the Archean lithosphere beneath the North China Craton is thin (reduced from 200 km to about 80 km),and has been replaced by a geochemically juvenile lithospheric mantle.This is a unique regional geological event,which has attracted worldwide attention.In the North China Block,Late Mesozoic extensional tectonics is evident by low-angle detachment faults,syntectonic plutons bounded by ductile faults,metamorphic core complexes (MCC) and widespread Jurassic to Cretaceous half-grabens filled by continental terrigenous deposits and volcanic rocks.At a regional scale,these structures share the same NW-SE extensional direction,while maintaining their own individual kinematics.In other words,the MCC feature a top-to-the-NW sense of shear,and syntectonic plutons are typified by a top-to-the-SE shearing deformations.Geochronological results indicate that the extensional structures were formed between 130-120 Ma.These extensional events lead to magmatic rock emplacement,distributed at the footwall of the detachment faults.Two different exhumation stages can be identified based on regional structural and magmatic interpretation:a Jurassic slow or negligible exhumation and a Cretaceous fast one assisted by normal faulting.These two cooling stages correspond to distinct geodynamic processes that occurred during the Jurassic and Cretaceous.Extensional tectonics appear to have been insignificant before the Early Cretaceous,and the process may be demonstrated by partial melting of the crust.The second stage,dominated by an extensional regime,developed after ca 120 Ma,and is tentatively correlated with crustal extension caused by lithospheric removal of the North China Craton.
文摘Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression
基金supported by the National Natural Science Foundation of China(Grant No.41688103)the International Cooperation Program of the Chinese Academy of Sciences(Grant No.GJHZ1776)。
文摘The Neo-Tethys Ocean was an eastward-gaping triangular oceanic embayment between Laurasia to the north and Gondwana to the south.The Neo-Tethys Ocean was initiated from the Early Permian with mircoblocks rifted from the northern margin of Gondwana.As the microblocks drifted northwards,the Neo-Tethys Ocean was expanded.Most of these microblocks collided with the Eurasia continent in the Late Triassic,leading to the final closure of the Paleo-Tethys Ocean,followed by oceanic subduction of the Neo-Tethys oceanic slab beneath the newly formed southern margin of the Eurasia continent.As the splitting of Gondwana continued,African-Arabian,Indian and Australian continents were separated from Gondwana and moved northwards at different rates.Collision of these blocks with the Eurasia continent occurred at different time during the Cenozoic,resulting in the closure of the Neo-Tethys Ocean and building of the most significant Alps-Zagros-Himalaya orogenic belt on Earth.The tectonic evolution of the Neo-Tethys Ocean shows different characteristics from west to east:Multi-oceanic basins expansion,bidirectional subduction and microblocks collision dominate in the Mediterranean region;northward oceanic subduction and diachronous continental collision along the Zagros suture occur in the Middle East;the Tibet and Southeast Asia are characterized by multi-block riftings from Gondwana and multi-stage collisions with the Eurasia continent.The negative buoyancy of subducting oceanic slabs can be considered as the main engine for northward drifting of Gondwana-derived blocks and subduction of the Neo-Tethys Ocean.Meanwhile,mantle convection and counterclockwise rotation of Gondwana-derived blocks and the Gondwana continent around an Euler pole in West Africa in non-free boundary conditions also controlled the evolution of the Neo-Tethys Ocean.
基金funded by the National Basic Research Program of China(973 Program,No.2012CB416701)National Natural Science Foundation of China(Grant 40972132)was partly supported by the State Key Laboratory for Mineral Deposits Research of Nanjing University(No.2008-Ⅰ-01)
文摘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 tufts 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 geo- dynamical 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 exten- sional 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 tectonics between both shores of the Pacific, such as mantle plume formation, scales of extensional and igneous rock assemblages and the age of basin and range tectonics, were caused mainly by the Yellowstone mantle plume in the eastern shore of the Pacific.
文摘The most prominent feature of the extensional tectonic framework of post high pressure (HP) and ultrahigh pressure (UHP) metamorphism in Dabieshan is the development of the multi layered extension detachment zones surrounding the core of the Luotian dome, and the separation of the UHP, HP and epidote blueschist units by the detachment zones, which form the vertically stacking sheet like slices of the HP and UHP metamorphic rocks. From the core outwards, exist the HP and UHP rock barren Dabie complex, UHP unit, HP unit and epidote blueschist unit. The extension tectonics of post HP and UHP metamorphic event constrain the distribution and present configuration of the HP and UHP metamorphic rocks, and the extensional tectonic framework bears some similarities to the Cordillera metamorphic core complex. It is suggested that partial melting happened in the Dabie gneiss complex (DGC) and UHP unit contemporaneously with the extrusion of UHP metamorphic rocks into the lower-middle crust. The formation and emplacement of the migmatite and granites are the response to the change in thermal state, facilitating the transfer from the compressive regime to extensional regime in the crust. The large scale crustal extension and uplift and the accompanying anatexis in Dabieshan are probably related to the delamination and magmatic underplating in the mantle and the lower crust.
文摘The Erlian fault basin group, a typical Basin and Range type fault basin group, was formed during Late Jurassic to Early Cretaceous, in which there are rich coal, oil and gas resources. In the present paper the abundant geological and petroleum information accumulated in process of industry oil and gas exploration and development of the Erlian basin group is comprehensively analyzed, the structures related to formation of basin are systematically studied, and the complete extensional tectonic system of this basin under conditions of wide rift setting and low extensional ratio is revealed by contrasting study with Basin and Range Province of the western America. Based on the above studies and achievements of the former workers, the deep background of the basin development is treated.
基金financially supported by the Nature Science Foundation of China (grants No.41372109,90914003 and 41672111)China Geological Survey (grants No.12120115068901,1212011120142 and 12120114064301)the National Science and Technology Works Special Project (grant No.2015FY310100)
文摘Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of NCC)during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma.
文摘The relationship between deposition and tectonics of sedimentary basins has been a significant subject in recent years.Using typical rift basins such as the Nanpu Sag as an example,combined with the analysis of the tectonics-palaeogeomorphology of basins,we undertook a detailed study of the differences of the third-order sequences in different basins,the combination of depositional systems within the sequence framework and the distribution of depocenters and subsidence centers.Our results revealed a significant relationship between the tectonics-palaeogeomorphology of rift basins and the filling styles of sedimentary sequences.The basin structure plays a primary role in controlling the development of the third-order sequences and the boundary of these sequences is easily formed in basins with gentle slopes,shallow water and a small area.The characteristics of the tectonics-palaeogeomorphology of rift basins are dominated by half-grabens of extensional faults,which affect the temporal and spatial combination of sedimentary systems within the sequences as well as the distribution of depocenters and subsidence centers.Based on the development rules of the faults dominating the half-grabens of extensional faults,rift basins are classified into two types: the single fault segmented-linkage type and the multi-fault combination type.The main controlling factors of the temporal and spatial combination of sedimentary systems and the distribution of depocenters and subsidence centers in different basins are different.The characteristics of early segmentation and later linkage of the faults play a critical role in controlling the sedimentary system combination within the sequence framework and the temporal and spatial differences of depocenters and subsidence centers of the single fault segmented-linkage rift basins,while the differences in fault activities are the dominating factors of the multi-fault combination rift basins.
基金supported by Basic Science Research Program through National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (2018R1C 186003851)to S.-I. Park and 2015RIDlAIA09058914 and NRF2019R1A2C1002211 to S. Kwonsupported by the 2017RlA6A1A07015374(Multidisciplinary study forassessment of large earthquake potentials in the Korean Peninsula) through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT, Korea to S.K
文摘During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where the Early-Middle Jurassic intra-arc volcano-sedimentary Oseosan Volcanic Complex was developed on top of the Late Triassic-Early Jurassic post-collisional sequences, namely the Chungnam Basin. The basin shortening was accommodated mostly by contractional faults and related folds. In the basement, regional high-angle reverse faults as well as low-angle thrusts accommodate the overall shortening, and are compatible with those preserved in the cover. This suggests that their spatial and temporal development is strongly dependent on the initial basin geometry and inherited structures.Changes in transport direction observed along the basement-sedimentary cover interface is a characteristic structural feature, reflecting sequential kinematic evolution during basin inversion. Propagation of basement faults also enhanced shortening of the overlying sedimentary cover sequences. We constrain timing of the Late Jurassic-Early Cretaceous(ca. 158-110 Ma) inversion from altered K-feldspar 40 Ar/39 Ar ages in stacked thrust sheets and K-Ar illite ages of fault gouges, along with previously reported geochronological data from the area. This "non-magmatic phase" of the Daebo Orogeny is contemporaneous with the timing of magmatic quiescence across the Korean Peninsula. We propose the role of flat/low-angle subduction of the Paleo-Pacific Plate for the development of the "Laramide-style" basement-involved orogenic event along East Asian continental margin.
基金supported by the National Key Basic Research Program of China(Grant No.2013CB429701)the National Natural Science Foundation of China(Grant Nos.41606083,91958210,41606050 and 41210005)+1 种基金AoShan Technological Innovation Projects of National Laboratory for Marine Science and Technology(Qingdao)(2015ASKJ03)National Marine Geological Special Project(DD20190236,DD20190365,DD20190377)。
文摘The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 545-kmlong active-source ocean bottom seismometer(OBS)wide-angle reflection/refraction profile in the East China Sea.The P wave velocity model shows that the Moho depth rises significantly,from approximately 30 km in the East China Sea shelf to approximately 16 km in the axis of the Okinawa Trough.The lower crustal high-velocity zone(HVZ)in the southern Okinawa Trough,with V_(p) of 6.8-7.3 km/s,is a remarkable manifestation of the mantle material upwelling and accretion to the lower crust.This confirms that the lower crustal high-velocity mantle accretion is developed in the southern Okinawa Trough.During the process of back-arc extension,the crustal structure of the southern Okinawa Trough is completely invaded and penetrated by the upper mantle material in the axis region.In some areas of the southern central graben,the crust may has broken up and entered the initial stage of seafloor spreading.The discontinuous HVZs in the lower crust in the back-arc region also indicate the migration of spreading centers in the back-arc region since the Cenozoic.The asthenosphere material upwelling in the continent-ocean transition zone is constantly driving the lithosphere eastward for episodic extension,and is causing evident tectonic migration in the Western Pacific back-arc region.