The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is st...The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is still rarely reported. In this study, a quantitative research method for tectonization intensity is proposed. The research result on Tahe-Lunnan oilfield shows that this method can not only quantitatively express the tectonization intensity, but also qualitatively reflect the macroscopic deform property and the evolution history of strata. Therefore, it is an effective method for analyzing the characteristics of tectonization. In addition, the realization of the method also can provide qualitative information for studying the influence and control of tectonization on hydrocarbon accumulation.展开更多
This work makes the quantitative constrain on tectonizations of the Gangdese block, south Qinghai-Tibetan Plateau. Apatite fission track (AFT) dating analyses of 15 samples collected across the Gangdese block show tha...This work makes the quantitative constrain on tectonizations of the Gangdese block, south Qinghai-Tibetan Plateau. Apatite fission track (AFT) dating analyses of 15 samples collected across the Gangdese block show that the Gangdese block went through two periods of tectonizations, during -37.2-18.5 Ma and 18.5 - 8.0 Ma in the south Gangdese block, and during -47.6-5.3 Ma and 5.3-0 Ma in the middle Gangdese block. Different upliftings did not take place in the first period and rapid uplifting occurred in the late period. Meantime, there are some differences be-tween the south and middle Gangdese block. Their uplifting rate is 180 m/Ma and 70 m/Ma respectively. The rapid up-lifting time in the middle Gangdese block lagged behind the time in the south Gangdese block. It is Chala-Jiacuo-Riduo fault zone that is similar to the Yarlung Zangbo fault zone in control of the tectonization.展开更多
A wealth of geological and geochemical evidence indicates that plate tectonics was initiated in the Archean,though its style differing from that in the Phanerozoic,largely due to higher temperatures of convective mant...A wealth of geological and geochemical evidence indicates that plate tectonics was initiated in the Archean,though its style differing from that in the Phanerozoic,largely due to higher temperatures of convective mantle.Understanding the specific characteristics for the operation of ancient plate tectonics is critical for deciphering the formation and evolution of continental crust on early Earth,as well as the progressive development of Earth’s habitability.Through an in-depth analysis of geology and geochemistry for two events of late Archean crustal growth in the North China Craton,this study suggests that Archean plate tectonics would likely undergo the gradual evolution from immature to mature phases.The North China Craton experienced two major episodes of crustal growth at~2.9-2.7 and~2.6-2.5 Ga,respectively,represented by peaks in isotopic model ages of Archean felsic gneisses and widespread mafic rocks in greenstone belts.Although the preserved mafic rocks in greenstone belts generally exhibit arc-like trace element signatures,the early mafic crust formed at~2.9-2.7 Ga is limited in volume,with most of it having been reworked within several hundred million years.Tonalite-trondhjemite-granodiorite(TTG),produced by partial melting of such mafic crust,show zircon Hf-O isotope compositions indicative of sources consisting of seawater-hydrothermally altered oceanic crustal rocks with varying ages,suggesting that the early mafic crust was likely dominated by oceanic basalts.The medium-to low-pressure signatures of TTG rocks further imply that the oceanic crust was not subducted deeply to mantle depths,but instead was accreted to the margin of proto-continental nuclei due to aborted subduction.In contrast,the~2.6-2.5 Ga crustal growth event preserved a greater volume of mafic rocks.For these mafic rocks,the enrichment of incompatible elements correlates with water contents estimated from whole-rock major elements,indicating that their arc-like trace element features were associated with fluid metasomatism of the source region.Integrated with regional geological evidence from~2.5 Ga,such as ophiolites containing ultrahigh-pressure mineral inclusions and eclogite-facies remnants of oceanic crust,these observations suggest that modern-style plate subduction was likely in operation by the end of the Late Archean.Therefore,the modern plate tectonics regime did not emerge abruptly,but underwent a gradual evolution controlled by the thermal state of plate margins.It is this evolving tectonic regime that drove the significant crustal growth during the Archean.The two distinct episodes of crustal growth ultimately led to the formation of the North China Craton.展开更多
The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents t...The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents the integration of morphometric indices to quantitatively assess the spatial variation of tectonic activity along the AFZ.The AFZ is an active fault with both strike-slip and normal fault components and consists of two main branches,Mercimekdağı-Çamdere Fault(MÇF)and Tokat Fault(TF)segments.This study aims to assess the relative tectonic activity of the AFZ using various morphometric indices,based on a 10 m resolution DEM,with the aid of ArcGIS and MATLAB software.For this purpose,morphometric indices such as hypsometric integral(HI:0.35-0.65),mountain front sinuosity(Smf:1.3-1.44),valley floor width-height ratio(Vf:0.15-2.28),asymmetry factor(AF:23-77),drainage basin shape(Bs:1.13-6.10)and normalized steepness index(ksn:1-498)were applied to 53 drainage basins.When the Smf and mean Vf indices results were evaluated,it was calculated that the uplift ratio of the region was more than 0.5 mm/yr.The spatial distribution of the relative tectonic activity(Iat)of the area was revealed by combining the obtained morphometric indices analysis results.According to the Iat result,it was concluded that the MercimekdağıÇamdere Fault and Tokat Fault segments have high tectonic activity,but the Mercimekdağı-Çamdere Fault segment has higher tectonic activity.The results obtained were also confirmed by field observations.This research provides valuable information for the evaluation of tectonic activity in drainage systems controlled by splay faults.展开更多
Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it pr...Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it protects a vital temperate mountainous forest ecosystem on the Loess Plateau.The reserve is centred around the Liupan Mountain range,one of China’s youngest mountain chains,formed by Himalayan tectonic movements.展开更多
The available heat content (stored heat energy) of hot dry rock (HDR) at a depth of 1–10 km in the global land crust is estimated to be 5.06×10~8 EJ,attracting considerable global attention.This paper presents a...The available heat content (stored heat energy) of hot dry rock (HDR) at a depth of 1–10 km in the global land crust is estimated to be 5.06×10~8 EJ,attracting considerable global attention.This paper presents a comprehensive analysis of the geological framework,HDR resource potential,exploration advancements,and the development of enhanced geothermal systems (EGSs) in China.HDR resources are extensively distributed across China.Within the depth range of 3–10 km,China’s estimated potential approximates2.29×10~7 EJ,with a theoretical power generation capacity of approximately 1.67×10^(16) k Wh.Replacing coal power with HDR can help to achieve a net emission reduction of 1.34×10^(16) kg CO_(2) (approximately1.34×10^(13) t),representing an emission reduction efficiency of 94.4%.Based on a development cycle of100 years,the average annual emission reduction reaches 1.34×10^(10) t CO_(2),equivalent to 117%of China’s annual carbon emissions in 2022.Furthermore,in the context of global warming,the development and utilization of HDR,which is feasible in virtually any region worldwide,offers significant potential to support global carbon reduction efforts.China has made substantial progress in HDR exploration in recent years.This paper systematically classifies China’s HDR resources into four genetic types—highly radioactive heat-producing,sedimentary basin,active volcanic,and intensely tectonic zones—and offers detailed exploration insights for each category.Each classification exhibits distinct geological and tectonic characteristics that influence heat source mechanisms and resource distribution.Furthermore,this paper documents significant advances in EGS construction,particularly in the Gonghe Basin on the northeastern margin of the Qianghai-Xizang Plateau and the Matouying uplift in the North China Basin,where successful reservoir stimulation,microseismic monitoring,and experimental power generation have been achieved.Despite these developments,challenges persist,including technical adaptability under complex geological conditions and the economic viability of large-scale HDR development.This paper suggests that future initiatives should emphasize resource exploration,technological research,and policy support to foster sustainable HDR resource development in China,thereby contributing to the global energy transition and environmental sustainability.展开更多
The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is si...The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.展开更多
The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of t...The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of the sediments.Major oxides,trace elements,and rare earth elements(REEs)obtained from the INAA technique are presented by analyzing the sediment samples collected from the shoreline of St.Martin’s Island,Bangladesh.The elemental ratios,comparison with average upper continental crust(UCC),binary diagrams(Th/Sc vs.Sc,La/Th vs.Hf,Th/Co vs.La/Sc),and chondrite normalized REE patterns exhibit substantial LREE enrichment,relatively fl at HREE fractionation,considerable negative Eu anomalies(average:0.72),indicates the derivation from a source dominated by felsic rock,with contribution from intermediate source and mafi c component.Sediments from St.Martin’s Island exhibit the deposition of sediments in transitional environments of active and passive continental margin settings.Weathering indices value of CIA,PIA,CIW,CIX,and K 2 O/Rb ratio show moderate chemical weathering,indicating that the sediments are chemically mature.Sedimentary redox indicative proxies,such as U/Th,V/Cr,and V/Sc,show an oxic depositional environment during sediment deposition.The intermediate CIA and other weathering index values of the St.Martin’s sediments show that the area had semiarid and humid climatic conditions throughout the deposition.The Rb/K ratio of the St.Martin’s sediments suggests that the development and deposition of the sedimentary sequence of St.Martin’s Island mainly occurred in a brackish water environment during the geological past.展开更多
Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system ...Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system is crucial in deep reservoir exploration.This study examined the first member and upper submember of the second member of the Dongying Formation in the Bodong Low Uplift in the Bohai Bay Basin(East China),documenting the petrologic features and physical properties of reservoirs in different tectonic sub-units through integrated analysis of log and rock data,along with core observation.A mechanism for deep reservoir formation in lacustrine rift basins was developed to elucidate the sedimentary and diagenetic processes in complex tectonic settings.The results show that tectonic activities result in the occurrence of provenances in multiple directions and the existence of reservoirs at varying burial depths,as well as the significant diversity in sedimentary and diagenetic processes.The grain sizes of the sandstones,influenced by transport pathways rather than the topography of the sedimentary area,exhibit spatial complexity due to tectonic frameworks,which determine the initial pore content of reservoirs.However,the burial depth,influenced by subsequent tectonic subsidence,significantly impacts pore evolution during diagenesis.Based on the significant differences of reservoirs in slope zone,low uplift and depression zone,we establish different tectonic-diagenetic models in deep complex tectonic units of lacustrine rift basins.展开更多
Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addi...Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.展开更多
Since the Paleozoic,the tectonic evolution of northeastern Eurasia has been primarily influenced by the Paleo-Asian Ocean and the Paleo-Pacific tectonic domains.However,the spatial and temporal frameworks,as well as t...Since the Paleozoic,the tectonic evolution of northeastern Eurasia has been primarily influenced by the Paleo-Asian Ocean and the Paleo-Pacific tectonic domains.However,the spatial and temporal frameworks,as well as the timing of the tectonic transition between these two oceanic domains,remain unclear.For addressing these issues,we present petrological,geochronological,and geochemical data for andesite and sandstone samples from the Seluohe Group along the Jilin-Yanji Suture between the Jiamusi-Khanka Block and the North China Craton.The geochemical results indicate that the andesite sample is high-Mg andesite.Its magma source was generated by the metasomatized mantle wedge influenced by fluids derived from the subducted slab in a continental island arc setting.The high-Mg andesite gives the crystallization ages of Early Triassic(249±3 Ma).The sandstone is immature greywacke with a maximum depositional age of Early Triassic(247±1 Ma),and its sediments primarily originate from concurrent magmatic rocks within a juvenile continental arc.Based on our new findings,we propose that the Seluohe Group represents an Early Triassic volcanic-sedimentary association with continental island arc characteristics associated with the southwestward subduction of the Heilongjiang Ocean.We identified a sedimentary basin intimately associated with one or more continental arcs along the northeastern edge of the North China Craton.We suggest that the southwestward subduction of the Jilin-Heilongjiang Ocean in the Early Mesozoic accounts for this continental arc setting.There is a distinct temporal gap between the closure of the Paleo-Asian Ocean(ca.260 Ma)and the onset of Paleo-Pacific plate subduction(234–220 Ma),which is essentially coeval with the southwestward subduction of the Jilin-Heilongjiang Ocean between 255 Ma and 239 Ma.展开更多
Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores s...Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores systematically the boundary,distribution,geological structure,and tectonic attributes of the Ordos prototype basin in the geological historical periods.The results show that the Ordos block is bounded to the west by the Engorwusu Fault Zone,to the east by the Taihangshan Mountain Piedmont Fault Zone,to the north by the Solonker-Xilamuron Suture Zone,and to the south by the Shangnan-Danfeng Suture Zone.The Ordos Basin boundary was the plate tectonic boundary during the Middle Proterozoic to Paleozoic,and the intra-continental deformation boundary in the Meso-Cenozoic.The basin survived as a marine cratonic basin covering the entire Ordos block during the Middle Proterozoic to Ordovician,a marine-continental transitional depression basin enclosed by an island arc uplift belt at the plate margin during the Carboniferous to Permian,a unified intra-continental lacustrine depression basin in the Triassic,and an intra-continental cratonic basin circled by a rift system in the Cenozoic.The basin scope has been decreasing till the present.The large,widespread prototype basin controlled the exploration area far beyond the present-day sedimentary basin boundary,with multiple target plays vertically.The Ordos Basin has the characteristics of a whole petroleum(or deposition)system.The Middle Proterozoic wide-rift system as a typical basin under the overlying Phanerozoic basin and the Cambrian-Ordovician passive margin basin and intra-cratonic depression in the deep-sited basin will be the important successions for oil and gas exploration in the coming years.展开更多
How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deform...How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deformation structures in the east Asian continent,however,provide excellent opportunities for reconstructing paleostress fields in continental interior in relation to the Paleo-Pacific/Eurasian plate interaction.Anisotropy of magnetic susceptibility(AMS),geological,and geochronological analyses of post-kinematic mafic dykes intruding the detachment fault zone of the Wulian metamorphic core complex(WL MCC)in Jiaodong Peninsula exemplify emplacement of mantle-sourced dykes in a WNW-ESE(301°-121°)oriented tectonic extensional setting at ca.120 Ma.In combination with the results from our previous kinematic analysis of the MCC,a ca.21°clockwise change in the direction of intraplate extension is obtained for early(135-122 Ma)extensional exhumation of the MCC to late(122-108 Ma)emplacement of the dykes.Such a change is suggested to be related to the variation in subduction direction of the Paleo-Pacific plate beneath the Eurasian plate,from westward(pre-122 Ma)to west-northwestward(post-122 Ma).展开更多
The Irtysh tectonic belt lies on the southern margin of the Chinese Altai Orogen. Several secondary shear zones with NW-SE strikes have developed in this tectonic belt, and the deformation processes are of great signi...The Irtysh tectonic belt lies on the southern margin of the Chinese Altai Orogen. Several secondary shear zones with NW-SE strikes have developed in this tectonic belt, and the deformation processes are of great significance to understanding the tectonic regime of the Altai Orogen in the Late Paleozoic. The Tuerhongshate ductile shear zone is located in the eastern Irtysh tectonic belt with obvious deformed structures. The felsic rocks are strongly mylonitized, exhibiting S-C fabrics, asymmetric rotational porphyroclasts, and bookshelf structures of the plagioclases, indicating a sinistral shear sense. The deformation mechanisms, lattice preferred orientations (LPOs) of quartz, and opening angles of quartz c-axis suggest that the deformation temperatures range from 400 to 500 ℃, consistent with higher-greenschist to lower-amphibolite facies conditions. The calculated kinematic vorticity values (W_(k)) of the studied samples range from 0.53 to 0.89 and indicate general shear to simple shear, based on rotational rigid porphyroclast method and oblique grain-shaped/quartz c-axis fabric method. The U-Pb ages of magmatic zircons in felsic mylonites indicate that the sinistral shear occurred after 296.7 ± 3.0 Ma (Early Permian) in the Tuerhongshate shear zone and persisted for approximately 13 Ma. Combined with the tectonic setting and the observed sinistral strike-slip shear indicators in the mylonite zone, these features demonstrate that the Irtysh tectonic belt was in a post-orogenic and strike-slip environment following the closure of the Irtysh Ocean.展开更多
1.Objective,The Luang Prabang(Laos)-Loei(Thailand)metallogenetic belt,located along the northwestern margin of the Indochina Block(Fig.1a)and endowed nearly 200 t of gold and more than 106 t of copper,is one of the mo...1.Objective,The Luang Prabang(Laos)-Loei(Thailand)metallogenetic belt,located along the northwestern margin of the Indochina Block(Fig.1a)and endowed nearly 200 t of gold and more than 106 t of copper,is one of the most important gold-copper metallogenic belts in Indo-China Peninsula.It has undergone tectonic changes during the Early Paleozoic to Mesozoic Proto-Paleo Tethys tectonic evolution,recorded by the Luang Prabang tectonic belt,the Nan-Uttaradit suture,and the Dien Bien Phu-Loei suture.展开更多
Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of ...Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.展开更多
The investigation of the tectonic deformation characteristics at the front margin of the Xu-Su arc tectonic belt provides important reference points for identifying and analyzing its genetic mechanism,tectonic evoluti...The investigation of the tectonic deformation characteristics at the front margin of the Xu-Su arc tectonic belt provides important reference points for identifying and analyzing its genetic mechanism,tectonic evolution process,and the latest evidence of tectonic deformation.In this study,two reflection seismic exploration profiles across the front margin of the Xu-Su arc tectonic belt are utilized to reveal that the Qinglongshan fault is the thrust fault of its front margin boundary.The kinematic properties and tectonic deformation characteristics of the internal faults in the front margin basin are also obtained.Using the Qinglongshan fault as the boundary,the middle and posterior margins of the Xu-Su arc tectonic belt are composed of numerous thrust faults,which suggest strong ancient tectonic movement.However,a large number of normal faults are developed within the front margin basin,with some faults exhibiting strike-slip and growth properties,which indicate strong neotectonic movement.Results reveal that the Xu-Su arc tectonic belt is a large-scale thrust-nappe structure that has undergone structural inversion.The Xu-Su arc tectonic belt experienced strong tectonic activity during the Middle Pleistocene,and the most recent tectonic deformation has extended into the front margin basin interior.展开更多
0 INTRODUCTION The Qilian Mountain Belt,at the forefront of the Tibetan Plateau's expansion,offers key insights into the plateau's tectonic deformation(Zuza et al.,2018;Zheng et al.,2010;Zhang et al.,2004;Tapp...0 INTRODUCTION The Qilian Mountain Belt,at the forefront of the Tibetan Plateau's expansion,offers key insights into the plateau's tectonic deformation(Zuza et al.,2018;Zheng et al.,2010;Zhang et al.,2004;Tapponnier et al.,2001;Meyer et al.,1998).The northwest-trending mountain ranges in the Qilian Shan(“Shan”means“Mountain”in Chinese)have significantly influenced this deformation(Zheng et al.,2013).展开更多
The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tecton...The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tectonic belt has been extensively studied,details regarding the tectonic processes involved in its development remain controversial.To better constrain the tectonic processes of this tectonic belt,we conducted detailed field geological mapping,zircon U-Pb geochronology,and whole-rock geochemical and Sr-Nd isotopic analyses.Our results show that intrusive rocks in the tectonic belt crystallized in ca.292-233 Ma,perhaps in an arc/subduction setting.Geochemical and Sr-Nd isotopic data suggest that Early Permian-Late Triassic ultramaficintermediate intrusions were sourced from the enriched mantle,whereas intermediate-acidic rocks were sourced from mixed crust-mantle.We present the tectonic model that involves:(1)Early Devonian-Early Permian intracontinental extension occurred in the northern margin of the Qaidam continent(ca.416-292 Ma);(2)Early Permian-Late Triassic northward subduction of the Paleo-Tethyan Ocean resulted in arc magmatism(ca.292-233 Ma);and(3)subsequent Late Triassic intracontinental extension(ca.233-215 Ma).Our results suggest that the Late Paleozoic-Early Mesozoic development of the Zongwulong Shan-Qinghai Nanshan was related to the opening,subduction,and slab retreat of the Paleo-Tethyan Ocean,which has key implications for the tectonic evolution of the northern Tibetan Plateau.展开更多
The extra-peninsular Gondwana Group rocks are exposed in narrow patches within the Lesser Himalayan sequence of the NE-Arunachal Himalayas,India.The bulk of sediments for the sandstones of the Gondwana Group were deri...The extra-peninsular Gondwana Group rocks are exposed in narrow patches within the Lesser Himalayan sequence of the NE-Arunachal Himalayas,India.The bulk of sediments for the sandstones of the Gondwana Group were derived from felsic/acidic to intermediate igneous rocks,with minor mafic input from the upper continental crust(UCC),as supported by various discrimination diagrams based on quantification of detrital minerals coupled with sandstone geochemistry.The inputs from metamorphic sources in subordinate amounts cannot be ruled out,as indicated by quantification of the quartz varieties.These sediments were found to be sourced from the interior part of a craton or shield and recycled platformal sediments which were derived from both passive and active margin settings.The sediments experienced a wide variance in climatic conditions,from arid to humid,suffering low-moderate-inten-sity weathering(CIA:63.43;CIW:86.18;WIP:44.84;PIA:75.37;ICV:2.39;C-value:0.42;PF:0.49;Sr/Cu:9.23 and Rb/Sr:1.68)within the vicinity of the low plains to moderate hills.Additionally,redox-sensitive elements indicate the deposition of sediments under oxygenated or oxygen-rich conditions(U_(au):−2.91;Th/U:7.37;U/Th:0.18;V/Cr:1.71;δU:0.67 and Ce/Ce^(*):0.93).展开更多
基金Supported by China Postdoctoral Science Fund (Grant No.2012M510714)
文摘The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is still rarely reported. In this study, a quantitative research method for tectonization intensity is proposed. The research result on Tahe-Lunnan oilfield shows that this method can not only quantitatively express the tectonization intensity, but also qualitatively reflect the macroscopic deform property and the evolution history of strata. Therefore, it is an effective method for analyzing the characteristics of tectonization. In addition, the realization of the method also can provide qualitative information for studying the influence and control of tectonization on hydrocarbon accumulation.
基金This work was supported by the President Fund of the Chinese Academy of Sciences (CAS) (Grant No. 99-775) the National Natural Science Foundation of China (Grant No. 40072068) Laboratory of Nuclear Analysis Technique, the CAS.
文摘This work makes the quantitative constrain on tectonizations of the Gangdese block, south Qinghai-Tibetan Plateau. Apatite fission track (AFT) dating analyses of 15 samples collected across the Gangdese block show that the Gangdese block went through two periods of tectonizations, during -37.2-18.5 Ma and 18.5 - 8.0 Ma in the south Gangdese block, and during -47.6-5.3 Ma and 5.3-0 Ma in the middle Gangdese block. Different upliftings did not take place in the first period and rapid uplifting occurred in the late period. Meantime, there are some differences be-tween the south and middle Gangdese block. Their uplifting rate is 180 m/Ma and 70 m/Ma respectively. The rapid up-lifting time in the middle Gangdese block lagged behind the time in the south Gangdese block. It is Chala-Jiacuo-Riduo fault zone that is similar to the Yarlung Zangbo fault zone in control of the tectonization.
基金supported by the National Natural Science Foundation of China(Grant No.42472258)the Shandong Provincial Natural Science Foundation for Excellent Young Scholars(Grant No.ZR2023YQ036).
文摘A wealth of geological and geochemical evidence indicates that plate tectonics was initiated in the Archean,though its style differing from that in the Phanerozoic,largely due to higher temperatures of convective mantle.Understanding the specific characteristics for the operation of ancient plate tectonics is critical for deciphering the formation and evolution of continental crust on early Earth,as well as the progressive development of Earth’s habitability.Through an in-depth analysis of geology and geochemistry for two events of late Archean crustal growth in the North China Craton,this study suggests that Archean plate tectonics would likely undergo the gradual evolution from immature to mature phases.The North China Craton experienced two major episodes of crustal growth at~2.9-2.7 and~2.6-2.5 Ga,respectively,represented by peaks in isotopic model ages of Archean felsic gneisses and widespread mafic rocks in greenstone belts.Although the preserved mafic rocks in greenstone belts generally exhibit arc-like trace element signatures,the early mafic crust formed at~2.9-2.7 Ga is limited in volume,with most of it having been reworked within several hundred million years.Tonalite-trondhjemite-granodiorite(TTG),produced by partial melting of such mafic crust,show zircon Hf-O isotope compositions indicative of sources consisting of seawater-hydrothermally altered oceanic crustal rocks with varying ages,suggesting that the early mafic crust was likely dominated by oceanic basalts.The medium-to low-pressure signatures of TTG rocks further imply that the oceanic crust was not subducted deeply to mantle depths,but instead was accreted to the margin of proto-continental nuclei due to aborted subduction.In contrast,the~2.6-2.5 Ga crustal growth event preserved a greater volume of mafic rocks.For these mafic rocks,the enrichment of incompatible elements correlates with water contents estimated from whole-rock major elements,indicating that their arc-like trace element features were associated with fluid metasomatism of the source region.Integrated with regional geological evidence from~2.5 Ga,such as ophiolites containing ultrahigh-pressure mineral inclusions and eclogite-facies remnants of oceanic crust,these observations suggest that modern-style plate subduction was likely in operation by the end of the Late Archean.Therefore,the modern plate tectonics regime did not emerge abruptly,but underwent a gradual evolution controlled by the thermal state of plate margins.It is this evolving tectonic regime that drove the significant crustal growth during the Archean.The two distinct episodes of crustal growth ultimately led to the formation of the North China Craton.
文摘The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents the integration of morphometric indices to quantitatively assess the spatial variation of tectonic activity along the AFZ.The AFZ is an active fault with both strike-slip and normal fault components and consists of two main branches,Mercimekdağı-Çamdere Fault(MÇF)and Tokat Fault(TF)segments.This study aims to assess the relative tectonic activity of the AFZ using various morphometric indices,based on a 10 m resolution DEM,with the aid of ArcGIS and MATLAB software.For this purpose,morphometric indices such as hypsometric integral(HI:0.35-0.65),mountain front sinuosity(Smf:1.3-1.44),valley floor width-height ratio(Vf:0.15-2.28),asymmetry factor(AF:23-77),drainage basin shape(Bs:1.13-6.10)and normalized steepness index(ksn:1-498)were applied to 53 drainage basins.When the Smf and mean Vf indices results were evaluated,it was calculated that the uplift ratio of the region was more than 0.5 mm/yr.The spatial distribution of the relative tectonic activity(Iat)of the area was revealed by combining the obtained morphometric indices analysis results.According to the Iat result,it was concluded that the MercimekdağıÇamdere Fault and Tokat Fault segments have high tectonic activity,but the Mercimekdağı-Çamdere Fault segment has higher tectonic activity.The results obtained were also confirmed by field observations.This research provides valuable information for the evaluation of tectonic activity in drainage systems controlled by splay faults.
文摘Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it protects a vital temperate mountainous forest ecosystem on the Loess Plateau.The reserve is centred around the Liupan Mountain range,one of China’s youngest mountain chains,formed by Himalayan tectonic movements.
基金supported by the National Key Research and Development Program of China (2021YFB1507401)Qinghai Province Clean Energy Minerals Special Project(2022013004qj004)Geological Survey Project of China Geological Survey (DD20221676, DD20230019)。
文摘The available heat content (stored heat energy) of hot dry rock (HDR) at a depth of 1–10 km in the global land crust is estimated to be 5.06×10~8 EJ,attracting considerable global attention.This paper presents a comprehensive analysis of the geological framework,HDR resource potential,exploration advancements,and the development of enhanced geothermal systems (EGSs) in China.HDR resources are extensively distributed across China.Within the depth range of 3–10 km,China’s estimated potential approximates2.29×10~7 EJ,with a theoretical power generation capacity of approximately 1.67×10^(16) k Wh.Replacing coal power with HDR can help to achieve a net emission reduction of 1.34×10^(16) kg CO_(2) (approximately1.34×10^(13) t),representing an emission reduction efficiency of 94.4%.Based on a development cycle of100 years,the average annual emission reduction reaches 1.34×10^(10) t CO_(2),equivalent to 117%of China’s annual carbon emissions in 2022.Furthermore,in the context of global warming,the development and utilization of HDR,which is feasible in virtually any region worldwide,offers significant potential to support global carbon reduction efforts.China has made substantial progress in HDR exploration in recent years.This paper systematically classifies China’s HDR resources into four genetic types—highly radioactive heat-producing,sedimentary basin,active volcanic,and intensely tectonic zones—and offers detailed exploration insights for each category.Each classification exhibits distinct geological and tectonic characteristics that influence heat source mechanisms and resource distribution.Furthermore,this paper documents significant advances in EGS construction,particularly in the Gonghe Basin on the northeastern margin of the Qianghai-Xizang Plateau and the Matouying uplift in the North China Basin,where successful reservoir stimulation,microseismic monitoring,and experimental power generation have been achieved.Despite these developments,challenges persist,including technical adaptability under complex geological conditions and the economic viability of large-scale HDR development.This paper suggests that future initiatives should emphasize resource exploration,technological research,and policy support to foster sustainable HDR resource development in China,thereby contributing to the global energy transition and environmental sustainability.
基金This study was jointly supported by the Science&Technology Fundamental Resources Investigation Program(2022FY101800)National Science Foundation(92162212)+1 种基金the project from the Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences,Wuhan)(TPR-2022-22)the International Geoscience Programme(IGCP-675)。
文摘The Ordos Basin(OB)in the western part of the North China Craton(NCC),was located at the jointed area of multi-plates and has recorded the Mesozoic tectonic characteristics.Its tectonic evolution in the Mesozoic is significant to understand the tectonic transformation of the northern margin of the NCC.In this work,the detrital zircon and apatite(U-Th)/He chronological system were analyzed in the northern part of the OB,and have provided new evidence for the regional tectonic evolution.The(U-Th)/He chronological data states the weighted ages of 240‒235 Ma,141 Ma with the peak distribution of 244 Ma,219 Ma,173 Ma,147‒132 Ma.The thermal evolution,geochronological data,and regional unconformities have proved four stages of regional tectonic evolution for the OB and its surroundings in the Mesozoic:(1)The Late Permian-Early Triassic;(2)the Late Triassic-Early Jurassic;(3)the Late Jurassic-Early Cretaceous;(4)the Late Cretaceous-Early Paleogene.It is indicated that the multi-directional convergence from the surrounding tectonic units has controlled the Mesozoic tectonic evolution of the OB.Four-stage tectonic evolution reflected the activation or end of different plate movements and provided new time constraints for the regional tectonic evolution of the NCC in the Mesozoic.
基金Supporting Program for funding this work under Project number(RSP2024R328),King Saud University,Riyadh,Saudi Arabia.
文摘The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of the sediments.Major oxides,trace elements,and rare earth elements(REEs)obtained from the INAA technique are presented by analyzing the sediment samples collected from the shoreline of St.Martin’s Island,Bangladesh.The elemental ratios,comparison with average upper continental crust(UCC),binary diagrams(Th/Sc vs.Sc,La/Th vs.Hf,Th/Co vs.La/Sc),and chondrite normalized REE patterns exhibit substantial LREE enrichment,relatively fl at HREE fractionation,considerable negative Eu anomalies(average:0.72),indicates the derivation from a source dominated by felsic rock,with contribution from intermediate source and mafi c component.Sediments from St.Martin’s Island exhibit the deposition of sediments in transitional environments of active and passive continental margin settings.Weathering indices value of CIA,PIA,CIW,CIX,and K 2 O/Rb ratio show moderate chemical weathering,indicating that the sediments are chemically mature.Sedimentary redox indicative proxies,such as U/Th,V/Cr,and V/Sc,show an oxic depositional environment during sediment deposition.The intermediate CIA and other weathering index values of the St.Martin’s sediments show that the area had semiarid and humid climatic conditions throughout the deposition.The Rb/K ratio of the St.Martin’s sediments suggests that the development and deposition of the sedimentary sequence of St.Martin’s Island mainly occurred in a brackish water environment during the geological past.
基金funded by the Open Fund of Key Laboratory of Marine Geology and Environment,Chinese Academy of Sciences(Grant No.MGE2020KG10)the Open Fund of Key Laboratory of Submarine Geosciences,Ministry of Natural Resources(Grant No.KLSG 2208)+2 种基金the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBMS-227,2023-JC-QN-0287)the Postgraduate Innovation and Practice Ability Development Fund of Xi'an Shiyou University(No.YCS23113046)the National Natural Science Foundation of China(Grant No.41802128,42076219)。
文摘Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system is crucial in deep reservoir exploration.This study examined the first member and upper submember of the second member of the Dongying Formation in the Bodong Low Uplift in the Bohai Bay Basin(East China),documenting the petrologic features and physical properties of reservoirs in different tectonic sub-units through integrated analysis of log and rock data,along with core observation.A mechanism for deep reservoir formation in lacustrine rift basins was developed to elucidate the sedimentary and diagenetic processes in complex tectonic settings.The results show that tectonic activities result in the occurrence of provenances in multiple directions and the existence of reservoirs at varying burial depths,as well as the significant diversity in sedimentary and diagenetic processes.The grain sizes of the sandstones,influenced by transport pathways rather than the topography of the sedimentary area,exhibit spatial complexity due to tectonic frameworks,which determine the initial pore content of reservoirs.However,the burial depth,influenced by subsequent tectonic subsidence,significantly impacts pore evolution during diagenesis.Based on the significant differences of reservoirs in slope zone,low uplift and depression zone,we establish different tectonic-diagenetic models in deep complex tectonic units of lacustrine rift basins.
基金supported by the National Natural Science Foundation of China(Nos.41872101 and 41790453-4)。
文摘Based on the detrital zircon U-Pb dating data,this paper discusses the provenance and constructs source-to-sink system of the Upper Jurassic in the North Yellow Sea Basin(NYSB),eastern North China Craton(ENCC).In addition,to avoid the bias of detrital zircon ages caused by variations in zircon fertility,we collected 1709 whole rock zirconium content values(ppm)from granitic rocks with different ages in the North China Craton(NCC).Based on mean Zr content of granitic rocks in each age,these granitic rocks can be divided into four groups:Group A consists of Jurassic,Group B consists of Paleozoic,Neo-Mesoproterozoic and Neoarchean,Group C consists of Early Cretaceous and Triassic,and Group D consists of Paleoproterozoic.This research assigns to these groups zircon fertility factors(ZFF)of 1,1.4,1.8 and 2.2.The U-Pb age of detrital zircons from Late Jurassic sediments corrected by ZFF is statistically analyzed(K-S test,similarity,crosscorrelation,linkeness,and multidimensional scaling).And combining with paleocurrent and paleogeography,we construct two source-to-sink systems:(1)Jiaodong uplift and Sulu Orogenic Belt as the source area and the North Yellow Sea Basin as the sink area;(2)Liaodong Peninsula as the source area and the North Yellow Sea Basin as the sink area.
基金Supported by the National Natural Science Foundation of China Nos.42230303,42430305 and 42302236Graduate Innovation Fund of Jilin University Number:2024CX109.
文摘Since the Paleozoic,the tectonic evolution of northeastern Eurasia has been primarily influenced by the Paleo-Asian Ocean and the Paleo-Pacific tectonic domains.However,the spatial and temporal frameworks,as well as the timing of the tectonic transition between these two oceanic domains,remain unclear.For addressing these issues,we present petrological,geochronological,and geochemical data for andesite and sandstone samples from the Seluohe Group along the Jilin-Yanji Suture between the Jiamusi-Khanka Block and the North China Craton.The geochemical results indicate that the andesite sample is high-Mg andesite.Its magma source was generated by the metasomatized mantle wedge influenced by fluids derived from the subducted slab in a continental island arc setting.The high-Mg andesite gives the crystallization ages of Early Triassic(249±3 Ma).The sandstone is immature greywacke with a maximum depositional age of Early Triassic(247±1 Ma),and its sediments primarily originate from concurrent magmatic rocks within a juvenile continental arc.Based on our new findings,we propose that the Seluohe Group represents an Early Triassic volcanic-sedimentary association with continental island arc characteristics associated with the southwestward subduction of the Heilongjiang Ocean.We identified a sedimentary basin intimately associated with one or more continental arcs along the northeastern edge of the North China Craton.We suggest that the southwestward subduction of the Jilin-Heilongjiang Ocean in the Early Mesozoic accounts for this continental arc setting.There is a distinct temporal gap between the closure of the Paleo-Asian Ocean(ca.260 Ma)and the onset of Paleo-Pacific plate subduction(234–220 Ma),which is essentially coeval with the southwestward subduction of the Jilin-Heilongjiang Ocean between 255 Ma and 239 Ma.
基金Supported by the National Natural Science Foundation of China(42330810)Major Science and Technology Project of PetroChina Changqing Oilfield Company(ZDZX2021-01).
文摘Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores systematically the boundary,distribution,geological structure,and tectonic attributes of the Ordos prototype basin in the geological historical periods.The results show that the Ordos block is bounded to the west by the Engorwusu Fault Zone,to the east by the Taihangshan Mountain Piedmont Fault Zone,to the north by the Solonker-Xilamuron Suture Zone,and to the south by the Shangnan-Danfeng Suture Zone.The Ordos Basin boundary was the plate tectonic boundary during the Middle Proterozoic to Paleozoic,and the intra-continental deformation boundary in the Meso-Cenozoic.The basin survived as a marine cratonic basin covering the entire Ordos block during the Middle Proterozoic to Ordovician,a marine-continental transitional depression basin enclosed by an island arc uplift belt at the plate margin during the Carboniferous to Permian,a unified intra-continental lacustrine depression basin in the Triassic,and an intra-continental cratonic basin circled by a rift system in the Cenozoic.The basin scope has been decreasing till the present.The large,widespread prototype basin controlled the exploration area far beyond the present-day sedimentary basin boundary,with multiple target plays vertically.The Ordos Basin has the characteristics of a whole petroleum(or deposition)system.The Middle Proterozoic wide-rift system as a typical basin under the overlying Phanerozoic basin and the Cambrian-Ordovician passive margin basin and intra-cratonic depression in the deep-sited basin will be the important successions for oil and gas exploration in the coming years.
基金supported by the National Natural Science Foundation of China(Grant Nos:42130801,41430211,90814006,and 42072226)the“Deep-time Digital Earth”Science and Technology Leading Talents Team Funds for the Central Universities for the Frontiers Science Center for Deep-time Digital Earth,CUGB(Fundamental Research Funds for the Central UniversitiesGrant No:2652023001).
文摘How the subduction direction of the Paleo-Pacific plate beneath the Eurasian plate changes in the Early Cretaceous remains highly controversial due to the disappearance of the subducted oceanic plate.Intraplate deformation structures in the east Asian continent,however,provide excellent opportunities for reconstructing paleostress fields in continental interior in relation to the Paleo-Pacific/Eurasian plate interaction.Anisotropy of magnetic susceptibility(AMS),geological,and geochronological analyses of post-kinematic mafic dykes intruding the detachment fault zone of the Wulian metamorphic core complex(WL MCC)in Jiaodong Peninsula exemplify emplacement of mantle-sourced dykes in a WNW-ESE(301°-121°)oriented tectonic extensional setting at ca.120 Ma.In combination with the results from our previous kinematic analysis of the MCC,a ca.21°clockwise change in the direction of intraplate extension is obtained for early(135-122 Ma)extensional exhumation of the MCC to late(122-108 Ma)emplacement of the dykes.Such a change is suggested to be related to the variation in subduction direction of the Paleo-Pacific plate beneath the Eurasian plate,from westward(pre-122 Ma)to west-northwestward(post-122 Ma).
基金support for this study was provided by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(No.XDB18030601)the One Hundred Talents Project of Shaanxi Province to Laixi Tongthe Natural Science Foundation of Shaanxi Province(No.2023-JC-QN-0283)granted to Chao Li.
文摘The Irtysh tectonic belt lies on the southern margin of the Chinese Altai Orogen. Several secondary shear zones with NW-SE strikes have developed in this tectonic belt, and the deformation processes are of great significance to understanding the tectonic regime of the Altai Orogen in the Late Paleozoic. The Tuerhongshate ductile shear zone is located in the eastern Irtysh tectonic belt with obvious deformed structures. The felsic rocks are strongly mylonitized, exhibiting S-C fabrics, asymmetric rotational porphyroclasts, and bookshelf structures of the plagioclases, indicating a sinistral shear sense. The deformation mechanisms, lattice preferred orientations (LPOs) of quartz, and opening angles of quartz c-axis suggest that the deformation temperatures range from 400 to 500 ℃, consistent with higher-greenschist to lower-amphibolite facies conditions. The calculated kinematic vorticity values (W_(k)) of the studied samples range from 0.53 to 0.89 and indicate general shear to simple shear, based on rotational rigid porphyroclast method and oblique grain-shaped/quartz c-axis fabric method. The U-Pb ages of magmatic zircons in felsic mylonites indicate that the sinistral shear occurred after 296.7 ± 3.0 Ma (Early Permian) in the Tuerhongshate shear zone and persisted for approximately 13 Ma. Combined with the tectonic setting and the observed sinistral strike-slip shear indicators in the mylonite zone, these features demonstrate that the Irtysh tectonic belt was in a post-orogenic and strike-slip environment following the closure of the Irtysh Ocean.
基金supported by the National Natural Science Foundation of China(Grant No.42102113)the National Key Research and Development Program of China(Grant No.2021YFC2901803)+1 种基金the China Geological Survey Project(Grant No.DD20230579)China Scholarship Council(File No.202108575008).
文摘1.Objective,The Luang Prabang(Laos)-Loei(Thailand)metallogenetic belt,located along the northwestern margin of the Indochina Block(Fig.1a)and endowed nearly 200 t of gold and more than 106 t of copper,is one of the most important gold-copper metallogenic belts in Indo-China Peninsula.It has undergone tectonic changes during the Early Paleozoic to Mesozoic Proto-Paleo Tethys tectonic evolution,recorded by the Luang Prabang tectonic belt,the Nan-Uttaradit suture,and the Dien Bien Phu-Loei suture.
基金financially supported by the Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxm X0487)the Open Fund of Key Laboratory of Sedimentary Basins and Oil and Gas Resources,the Ministry of Natural Resources(No.cdcgs2022006)+2 种基金the National Natural Science Foundation of China(No.42072001)the China Geological Survey(No.DD20190018)the Science and Technology Innovation Fund for Postgraduates of Chongqing University of Science and Technology(No.YKJCX2220101)。
文摘Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.
基金The active fault exploration and seismic risk assessment project of Huaibei and the research and development project of Beijing Disaster Prevention Technology Co.,Ltd.(FZKJYF202201)jointly funded this work。
文摘The investigation of the tectonic deformation characteristics at the front margin of the Xu-Su arc tectonic belt provides important reference points for identifying and analyzing its genetic mechanism,tectonic evolution process,and the latest evidence of tectonic deformation.In this study,two reflection seismic exploration profiles across the front margin of the Xu-Su arc tectonic belt are utilized to reveal that the Qinglongshan fault is the thrust fault of its front margin boundary.The kinematic properties and tectonic deformation characteristics of the internal faults in the front margin basin are also obtained.Using the Qinglongshan fault as the boundary,the middle and posterior margins of the Xu-Su arc tectonic belt are composed of numerous thrust faults,which suggest strong ancient tectonic movement.However,a large number of normal faults are developed within the front margin basin,with some faults exhibiting strike-slip and growth properties,which indicate strong neotectonic movement.Results reveal that the Xu-Su arc tectonic belt is a large-scale thrust-nappe structure that has undergone structural inversion.The Xu-Su arc tectonic belt experienced strong tectonic activity during the Middle Pleistocene,and the most recent tectonic deformation has extended into the front margin basin interior.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0901)the State Key Laboratory of Earthquake Dynamics(No.LED2023B04)+1 种基金the National Natural Science Foundation of China(Nos.42272242,W2411033,W2521003)the Science and Technology Plan of Gansu Province(No.22JR11RA088)。
文摘0 INTRODUCTION The Qilian Mountain Belt,at the forefront of the Tibetan Plateau's expansion,offers key insights into the plateau's tectonic deformation(Zuza et al.,2018;Zheng et al.,2010;Zhang et al.,2004;Tapponnier et al.,2001;Meyer et al.,1998).The northwest-trending mountain ranges in the Qilian Shan(“Shan”means“Mountain”in Chinese)have significantly influenced this deformation(Zheng et al.,2013).
基金supported by the National Natural Science Foundation of China(No.42372256)the Basic Science Center for Tibetan Plateau Earth System(No.41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0708)。
文摘The Zongwulong Shan-Qinghai Nanshan tectonic belt of the northern Xizang Plateau experienced a protracted tectonica history,including the openings and closures of the Proto-and Paleo-Tethyan Oceans.Although the tectonic belt has been extensively studied,details regarding the tectonic processes involved in its development remain controversial.To better constrain the tectonic processes of this tectonic belt,we conducted detailed field geological mapping,zircon U-Pb geochronology,and whole-rock geochemical and Sr-Nd isotopic analyses.Our results show that intrusive rocks in the tectonic belt crystallized in ca.292-233 Ma,perhaps in an arc/subduction setting.Geochemical and Sr-Nd isotopic data suggest that Early Permian-Late Triassic ultramaficintermediate intrusions were sourced from the enriched mantle,whereas intermediate-acidic rocks were sourced from mixed crust-mantle.We present the tectonic model that involves:(1)Early Devonian-Early Permian intracontinental extension occurred in the northern margin of the Qaidam continent(ca.416-292 Ma);(2)Early Permian-Late Triassic northward subduction of the Paleo-Tethyan Ocean resulted in arc magmatism(ca.292-233 Ma);and(3)subsequent Late Triassic intracontinental extension(ca.233-215 Ma).Our results suggest that the Late Paleozoic-Early Mesozoic development of the Zongwulong Shan-Qinghai Nanshan was related to the opening,subduction,and slab retreat of the Paleo-Tethyan Ocean,which has key implications for the tectonic evolution of the northern Tibetan Plateau.
文摘The extra-peninsular Gondwana Group rocks are exposed in narrow patches within the Lesser Himalayan sequence of the NE-Arunachal Himalayas,India.The bulk of sediments for the sandstones of the Gondwana Group were derived from felsic/acidic to intermediate igneous rocks,with minor mafic input from the upper continental crust(UCC),as supported by various discrimination diagrams based on quantification of detrital minerals coupled with sandstone geochemistry.The inputs from metamorphic sources in subordinate amounts cannot be ruled out,as indicated by quantification of the quartz varieties.These sediments were found to be sourced from the interior part of a craton or shield and recycled platformal sediments which were derived from both passive and active margin settings.The sediments experienced a wide variance in climatic conditions,from arid to humid,suffering low-moderate-inten-sity weathering(CIA:63.43;CIW:86.18;WIP:44.84;PIA:75.37;ICV:2.39;C-value:0.42;PF:0.49;Sr/Cu:9.23 and Rb/Sr:1.68)within the vicinity of the low plains to moderate hills.Additionally,redox-sensitive elements indicate the deposition of sediments under oxygenated or oxygen-rich conditions(U_(au):−2.91;Th/U:7.37;U/Th:0.18;V/Cr:1.71;δU:0.67 and Ce/Ce^(*):0.93).
