We performed spectral analyses on the ages of 89 well-dated major geological events of the last 260 Myr from the recent geologic literature. These events include times of marine and non-marine extinctions,major ocean-...We performed spectral analyses on the ages of 89 well-dated major geological events of the last 260 Myr from the recent geologic literature. These events include times of marine and non-marine extinctions,major ocean-anoxic events, continental flood-basalt eruptions, sea-level fluctuations, global pulses of intraplate magmatism, and times of changes in seafloor-spreading rates and plate reorganizations. The aggregate of all 89 events shows ten clusters in the last 260 Myr, spaced at an average interval of ~ 26.9 Myr, and Fourier analysis of the data yields a spectral peak at 27.5 Myr at the ≥96% confidence level. A shorter period of ~ 8.9 Myr may also be significant in modulating the timing of geologic events.Our results suggest that global geologic events are generally correlated, and seem to come in pulses with an underlying ~ 27.5-Myr cycle. These cyclic pulses of tectonics and climate change may be the result of geophysical processes related to the dynamics of plate tectonics and mantle plumes, or might alternatively be paced by astronomical cycles associated with the Earth’s motions in the Solar System and the Galaxy.展开更多
There are five major geological events in Precambrian complex, Taihangshan region determined by researching into geology and isotopic chronology of the complex. Basaltic magma erupted and quartz-dioritic to tonalitic ...There are five major geological events in Precambrian complex, Taihangshan region determined by researching into geology and isotopic chronology of the complex. Basaltic magma erupted and quartz-dioritic to tonalitic magma intruded in earlier neo-Archaean, which formed hornblende-plagiogneiss of Fuping gneiss complex and metamorphic mafic rock enclaves in TTGgneiss complex. Granulite facies metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Lüliang movement. gneiss complex. Granulite facies metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Lüliang movement.展开更多
The Yanshan Basin,located in northern North China,underwent three primary stages in the Mesoproterozoic,and corresponding biotas have been summarized for each stage in the present study.The three stages are stage A(th...The Yanshan Basin,located in northern North China,underwent three primary stages in the Mesoproterozoic,and corresponding biotas have been summarized for each stage in the present study.The three stages are stage A(the lower part of the Changcheng Group which dominated by clastic sediments),stage B(the upper part of the Changcheng Group to the Jixian Group which characterized by carbonate sediments),and stage C(the upper part of the Jixian Group which dominated by clastic sediments).This paper will focus on the evolution of biota during stage B.Microbiota of the stage B exhibits a high level of diversity and abundance.Planktonic microfossils have various forms and complex decorations.Most microfossils are small.In stage B,there was great variation in the biotic abundance and diversity,the average diameter of spherical benthic microfossils,and the maximum diameter of the spherical microfossils.We analyzed these parameters and identified two typical biotic events,and both biotic events were corresponded with geological events.The first event occurred in the third member of the Dahongyu Formation.In this era,the maximum diameter of the silicified microfossils significantly increased,and large,spherical planktonic specimens are abundant.The flourishing of large organisms in the strata is presumably related to volcanic activity.The second event occurred in the third member of the Gaoyuzhuang Formation.During this era,the microfossil assemblage changed significantly.The changes correspond with a decline in stromatolites as well as the transformations of the carbon isotope ratios and the elemental geochemistry.展开更多
The 8^(th) Symposium of IGCP 506 was held in Bucharest(Romania)during August-September,2009.At the 5th IGCP Symposium in Hammamet(Tunisia),a proposal was made by Mihai E.Popa to organize the symposium in Romania and w...The 8^(th) Symposium of IGCP 506 was held in Bucharest(Romania)during August-September,2009.At the 5th IGCP Symposium in Hammamet(Tunisia),a proposal was made by Mihai E.Popa to organize the symposium in Romania and we had agreed.展开更多
This paper gives an account of the research that the authors conducted on the cyclic sequences, events and evolutionary history from Proterozoic to Meso-Cenozoic in the Sino-Korean plate based on the principle of the ...This paper gives an account of the research that the authors conducted on the cyclic sequences, events and evolutionary history from Proterozoic to Meso-Cenozoic in the Sino-Korean plate based on the principle of the Cosmos-Earth System. The authors divided this plate into 20 super-cyclic or super-mega-cyclic periods and more than 100 Oort periods. The research focused on important sea flooding events, uplift interruption events, tilting movement events, molar-tooth carbonate events, thermal events, polarity reversal events, karst events, volcanic explosion events and storm events, as well as types of resource areas and paleotectonic evolution. By means of the isochronous theory of the Cosmos-Earth System periodicity and based on long-excentricity and periodicity, the authors elaborately studied the paleogeographic evolution of the aulacogen of the Sino-Korean plate, the oolitic beach platform formation, the development of foreland basin and continental rift valley basin, and reconstructed the evolution展开更多
Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been esta...Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been established. Basic lava eruption occurred in the span of 2868-2932 Ma, resulting in the formation of the early crust. The TTG magma emplacement took place c.2761 Ma ago. Subsequently basic magma intruded into the supracrustal rocks at 2650 Ma, resulting in crustal thickening. The thickening was enhanced at 2561-2503 Ma by the widespread intrusions of granodioritic magma. In the period of 2477-2461 Ma charnockite intruded, accompanied by regional granulite facies metamorphism. The second stage of granulite facies metamorphism occurred c. 2300 Ma ago, and finally pink granite intrusions at 2144-2087 Ma resulted in the formation of a granite zone.展开更多
The North China Craton(NCC)is one of the most ancient cratons in the world and records a complex geological evolution since the early Precambrian.In addition to recording major geological events similar to those of ot...The North China Craton(NCC)is one of the most ancient cratons in the world and records a complex geological evolution since the early Precambrian.In addition to recording major geological events similar to those of other cratons,the NCC also exhibits some unique features such as multi-stage cratonization(late Archaean and Palaeoproterozoic)and long-term rifting during the Meso-Neoproterozoic.The NCC thus provides one of the best examples to address secular changes in geological history and metallogenic epochs in the evolving Earth.We summarize the major geological events and metallogenic systems of the NCC,so that the evolutionary patterns of the NCC can provide a better understanding of the Precambrian NCC and facilitate comparison of the NCC with other ancient continental blocks globally.The NCC experienced three major tectonic cycles during the Precambrian:(1)Neoarchaean crustal growth and stabilization;(2)Palaeoproterozoic rifting-subduction-accretion-collision with imprints of the Great Oxidation Event and(3)Meso-Neoproterozoic multi-stage rifting.A transition from primitive-to modern-style plate tectonics occurred during the early Precambrian to late Proterozoic and is evidenced by the major geological events.Accompanying these major geological events,three major metallogenic systems are identified:(1)the Archaean banded iron formation system;(2)Palaeoproterozoic Cu-Pb-Zn and Mg-B systems and(3)a Mesoproterozoic rare earth element-Fe-Pb-Zn system.The ore-deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities.展开更多
We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data fr...We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data from six loci.Our results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago,and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late Miocene.The timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon,and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.展开更多
Based on the“unidirectional break-up and convergence”geodynamic model,this study investigates the impact of the evolution of the Tethyan domain on the formation of petroleum systems in the Sichuan super basin and ex...Based on the“unidirectional break-up and convergence”geodynamic model,this study investigates the impact of the evolution of the Tethyan domain on the formation of petroleum systems in the Sichuan super basin and explores the enrichment pattern of natural gas.The results show that,firstly,the Sichuan Basin and its surrounding areas have experienced two unidirectional rifting-aggregation cycles triggered by the Proto-Tethys Ocean and the Paleo-Tethys Ocean during the Neoproterozoic to Triassic.During Jurassic–Cenozoic,the Sichuan Basin is incorporated in the circum-Tibetan plateau basin-mountain coupled tectonic domain system.The episodic tectonic movements within the plate control the sedimentary infill styles.Second,the evolution of the Tethyan domain,paleoclimatic environment and major geological events controlled the formation and distribution of high-quality source rocks within the basin.The rift valley and intracratonic rift,passive continental margin slope,and intracratonic sags are favorable areas for the development of source rocks.Third,the evolution of the Tethyan domain,supercontinent cycles,global sea level changes,and tectono-climatic events controlled the distribution of carbonate platform and reservoir-caprock combinations.The cratonic platform margins and sub-platform internal high terrains are key areas for finding carbonate high-energy facies belts.Syndepositional paleo-uplifts and surrounding slopes,regional unconformities,and later faults zone are areas where large-scale carbonate reservoirs are distributed.The regional evaporite or shale caprock are beneficial for the large-scale preservation of oil and gas in the basin.Fourth,the spatio-temporal matching relationship of reservoir forming factors influenced by the early tectonic-sedimentary evolution pattern and the degree of later tectonic modification is the key to oil and gas enrichment.Future oil and gas exploration should focus on potential gas systems during the Sinian rift period,Cambrian pre-salt gas systems in the eastern and southern Sichuan,as well as whole oil and gas systems of Permian and Triassic.展开更多
Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other cli...Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise.展开更多
Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two ...Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous （more than 70.0 Ma）. There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi｜s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene （E/O） tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.展开更多
The zircon U-Pb chronology database provides a good opportunity to obtain important zircon growth peak periods in the Earth’s history so as to study the origin and evolution of the crust.It should be noted that resea...The zircon U-Pb chronology database provides a good opportunity to obtain important zircon growth peak periods in the Earth’s history so as to study the origin and evolution of the crust.It should be noted that research preference affects the objectivity of zircon sampling,leading to hot data in the database and age statistics.To evaluate the influence of hot data on statistical results,the W and Y indexes are introduced.Using a Gaussian model of multipeak fitting of zircon U-Pb age frequencies,we identify seven major growth peaks in zircons from the Chinese continental crust,which are 2498.95,1855.82,828.88,444.29,249.46,131.96,and 58.21 Ma.Due to differences in the time scales of zircon growth peaks,these peaks can be divided into two categories:first-order zircon growth peaks(Ⅰ)and second-order zircon growth peaks(Ⅱ),which represent longer and shorter time scales,perhaps due to different kinds of geological dynamics,respectively.In addition,there are clear correspondences between these ages and various geological events recognized by most scholars,namely,the Wutai orogeny,Lvliang orogeny,Jinning orogeny,Caledonian orogeny,Indosinian orogeny,Yanshanian orogeny,and Himalayan orogeny,respectively.展开更多
The present review is aimed at correlating major geologic events of the Cauvery Basin with analogous global episodes. The Cauvery Basin came into existence due to Gondwana break up during Late Jurassic-Early Cretaceou...The present review is aimed at correlating major geologic events of the Cauvery Basin with analogous global episodes. The Cauvery Basin came into existence due to Gondwana break up during Late Jurassic-Early Cretaceous by taphrogenic rift process. The first marine transgression close to Aptian/Albian boundary at the western margin of the basin terminates the syn-rift tectonic phase, which is also precise in adjoining Krishna-Godavari （KG） Basin. Two regional tectonic episodes are well documented in the basin which have global significance viz. （1） A major basinal uplift during late Turonian caused by Marion hot mantle plume resulted in widespread subaqueous volcanism in the southern part of the Cauvery Basin. This uplift also ted to relative sea level （RSL） fall of about 100 m in Cauvery and KG Basins and an unconformity of a magnitude of 2.3 Ma. The RSL fatt closely correlates with global sea level faU. This volcanic episode also resulted in Madagascar detachment from India. （2） The reunion hot mantle plume that ted to Deccan volcanism in central India resulted in E-SE tilt of the Cauvery Basin during upper Maastrichtian （CFI-CF3 zones）. This tilt caused a sea level fall of about 80 m and lateral withdrawal of sea by about 50 km developing a major erosional unconformity ranging in magnitude of -1.8-30 My. The magnitude of RSL correlates wetl with global sea level fall. This sea level fall caused widespread development of canyon features in the Cauvery Basin resulting in differential subaqueous erosion. The globally significant ocean anoxic events viz. OAE-Ib, OAE-1d, OAE-2 and OAE-3 are fairly discernible in the Cauvery Basin. The new isotopic palaeotemperature data suggests that southern India and Madagascar were located apparently in middle latitudes within the tropical-subtropical climatic zone during Atbian and early Maastrichtian. The magnitude of hiatus across K-Pg boundary varying from 0 to 30 Ma is estimated based on ptanktic foraminifera for subsurface sections. The magnetostratigraphy of outcrop sediments with rich fossil evidences reveals that magnetic polarity reversals consist of 13 mag- netozones in the Late Cretaceous sedimentary strata.展开更多
The geological evolution of Australia is closely linked to supercontinent cycles that have characterised the tectonic evolution of Earth,with most geological and metallogenic events relating to supercontinent/supercra...The geological evolution of Australia is closely linked to supercontinent cycles that have characterised the tectonic evolution of Earth,with most geological and metallogenic events relating to supercontinent/supercraton assembly and breakup.Australia mainly grew from W–E,with two major Archean cratons,the Yilgarn and Pilbara cratons,forming the oldest part of the continent in the West Australian Element.The centre of the continent consists of the mainly Paleoproterozoic–Mesoproterozoic North and South Australian elements,whereas the E is dominated by the Neoproterozoic–Mesozoic Tasman Element.The West,North and South Australian elements initially assembled during the Paleoproterozoic amalgamation of Nuna,and the Tasman Element formed mostly as a Paleozoic accretionary margin during the assembly of Gondwana-Pangea.Australia’s present position as a relatively stable continent resulted from the breakup of Gondwana.Australia is currently moving northward toward SE Asia,probably reflecting the earliest stages of the assembly of the next supercontinent,Amasia.展开更多
The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal ...The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal thickness,topography,and distribution of structures.However,the interpreted boundaries demarcated by different features varied widely.As research progresses,the understanding of the lunar structure is continuously improving,and new types of structures are constantly being discovered.The previous structural classification system needs to be updated.According to the major geological events and dynamic evolution,the evolutionary history of the Moon can be divided into 3 stages and 1 pivotal event.The first stage(4.52 to 4.3 Ga)is the evolution of the magmatic ocean,and it was dominated by endogenic processes.The formation of South Pole-Aitken(SPA)basin(~4.3 Ga)is the pivotal event of crustal evolution and indicates that the lunar crust had cooled and consolidated to sufficient rigidity to preserve structures.Both endogenic and exogenic processes were active in the second stage(4.3 to 3.0 Ga),which results in numerous impact basins,mare basalt flooding,and different types of associated structures.The last stage(3.0 Ga to the present)is late neotectonic activity,which has weak modification of the tectonic framework.Response of tectonic framework and structure to lunar major geological events had been organized and discussed in this paper,and key scientific issues are summarized.This study can provide reference and support for implementation of subsequent lunar exploration projects.展开更多
基金Research was partly funded by an NYU Research Challenge Fund Grant。
文摘We performed spectral analyses on the ages of 89 well-dated major geological events of the last 260 Myr from the recent geologic literature. These events include times of marine and non-marine extinctions,major ocean-anoxic events, continental flood-basalt eruptions, sea-level fluctuations, global pulses of intraplate magmatism, and times of changes in seafloor-spreading rates and plate reorganizations. The aggregate of all 89 events shows ten clusters in the last 260 Myr, spaced at an average interval of ~ 26.9 Myr, and Fourier analysis of the data yields a spectral peak at 27.5 Myr at the ≥96% confidence level. A shorter period of ~ 8.9 Myr may also be significant in modulating the timing of geologic events.Our results suggest that global geologic events are generally correlated, and seem to come in pulses with an underlying ~ 27.5-Myr cycle. These cyclic pulses of tectonics and climate change may be the result of geophysical processes related to the dynamics of plate tectonics and mantle plumes, or might alternatively be paced by astronomical cycles associated with the Earth’s motions in the Solar System and the Galaxy.
文摘There are five major geological events in Precambrian complex, Taihangshan region determined by researching into geology and isotopic chronology of the complex. Basaltic magma erupted and quartz-dioritic to tonalitic magma intruded in earlier neo-Archaean, which formed hornblende-plagiogneiss of Fuping gneiss complex and metamorphic mafic rock enclaves in TTGgneiss complex. Granulite facies metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Lüliang movement. gneiss complex. Granulite facies metamorphism and emplacement of biotite-plagiogneiss occurred in late neo-Archaean. Extension and uplifting from the end of neo-Archaean to Paleoproterozoic era formed Chengnanzhuang large extensional deformation zones and metamorphic mafic veins emplaced into the deformation zones. Remobilization of Precambrian complex and tectonic uplifting in late Paleoproterozoic era formed Longquanguan ductile shear zone and emplacement of Nanying gneiss. Occurrence of regional granite pegmatite at the end of Paleoproterozoic era means the end of the Lüliang movement.
基金supported by National Basic Research Program of China (Grant No. 2011CB808800)National Natural Science Foundation of China (Grant No. 41272015)
文摘The Yanshan Basin,located in northern North China,underwent three primary stages in the Mesoproterozoic,and corresponding biotas have been summarized for each stage in the present study.The three stages are stage A(the lower part of the Changcheng Group which dominated by clastic sediments),stage B(the upper part of the Changcheng Group to the Jixian Group which characterized by carbonate sediments),and stage C(the upper part of the Jixian Group which dominated by clastic sediments).This paper will focus on the evolution of biota during stage B.Microbiota of the stage B exhibits a high level of diversity and abundance.Planktonic microfossils have various forms and complex decorations.Most microfossils are small.In stage B,there was great variation in the biotic abundance and diversity,the average diameter of spherical benthic microfossils,and the maximum diameter of the spherical microfossils.We analyzed these parameters and identified two typical biotic events,and both biotic events were corresponded with geological events.The first event occurred in the third member of the Dahongyu Formation.In this era,the maximum diameter of the silicified microfossils significantly increased,and large,spherical planktonic specimens are abundant.The flourishing of large organisms in the strata is presumably related to volcanic activity.The second event occurred in the third member of the Gaoyuzhuang Formation.During this era,the microfossil assemblage changed significantly.The changes correspond with a decline in stromatolites as well as the transformations of the carbon isotope ratios and the elemental geochemistry.
文摘The 8^(th) Symposium of IGCP 506 was held in Bucharest(Romania)during August-September,2009.At the 5th IGCP Symposium in Hammamet(Tunisia),a proposal was made by Mihai E.Popa to organize the symposium in Romania and we had agreed.
文摘This paper gives an account of the research that the authors conducted on the cyclic sequences, events and evolutionary history from Proterozoic to Meso-Cenozoic in the Sino-Korean plate based on the principle of the Cosmos-Earth System. The authors divided this plate into 20 super-cyclic or super-mega-cyclic periods and more than 100 Oort periods. The research focused on important sea flooding events, uplift interruption events, tilting movement events, molar-tooth carbonate events, thermal events, polarity reversal events, karst events, volcanic explosion events and storm events, as well as types of resource areas and paleotectonic evolution. By means of the isochronous theory of the Cosmos-Earth System periodicity and based on long-excentricity and periodicity, the authors elaborately studied the paleogeographic evolution of the aulacogen of the Sino-Korean plate, the oolitic beach platform formation, the development of foreland basin and continental rift valley basin, and reconstructed the evolution
文摘Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been established. Basic lava eruption occurred in the span of 2868-2932 Ma, resulting in the formation of the early crust. The TTG magma emplacement took place c.2761 Ma ago. Subsequently basic magma intruded into the supracrustal rocks at 2650 Ma, resulting in crustal thickening. The thickening was enhanced at 2561-2503 Ma by the widespread intrusions of granodioritic magma. In the period of 2477-2461 Ma charnockite intruded, accompanied by regional granulite facies metamorphism. The second stage of granulite facies metamorphism occurred c. 2300 Ma ago, and finally pink granite intrusions at 2144-2087 Ma resulted in the formation of a granite zone.
基金funded by the 973 program(Grant No.2012CB4166006)supported by the State Ministry of Science and Technology,and research programs(Grant Nos.41530208,41210003 and 41502182)+1 种基金supported by the National Nature Science Foundation of ChinaChina Postdoctoral Science Foundation(Grant Nos.2015M570147 and 2016T90133)
文摘The North China Craton(NCC)is one of the most ancient cratons in the world and records a complex geological evolution since the early Precambrian.In addition to recording major geological events similar to those of other cratons,the NCC also exhibits some unique features such as multi-stage cratonization(late Archaean and Palaeoproterozoic)and long-term rifting during the Meso-Neoproterozoic.The NCC thus provides one of the best examples to address secular changes in geological history and metallogenic epochs in the evolving Earth.We summarize the major geological events and metallogenic systems of the NCC,so that the evolutionary patterns of the NCC can provide a better understanding of the Precambrian NCC and facilitate comparison of the NCC with other ancient continental blocks globally.The NCC experienced three major tectonic cycles during the Precambrian:(1)Neoarchaean crustal growth and stabilization;(2)Palaeoproterozoic rifting-subduction-accretion-collision with imprints of the Great Oxidation Event and(3)Meso-Neoproterozoic multi-stage rifting.A transition from primitive-to modern-style plate tectonics occurred during the early Precambrian to late Proterozoic and is evidenced by the major geological events.Accompanying these major geological events,three major metallogenic systems are identified:(1)the Archaean banded iron formation system;(2)Palaeoproterozoic Cu-Pb-Zn and Mg-B systems and(3)a Mesoproterozoic rare earth element-Fe-Pb-Zn system.The ore-deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences to S.Q.L.(XDB31000000)National Natural Sciences Foundation of China to Y.F.L.(NSFC-31860602,32170463,31660611)。
文摘We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data from six loci.Our results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago,and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late Miocene.The timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon,and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.
基金Supported by the National Natural Science of China(U22B6002)National Natural Science Foundation of China(U2344209)Major Science and Technology Project of PetroChina(2023ZZ02)。
文摘Based on the“unidirectional break-up and convergence”geodynamic model,this study investigates the impact of the evolution of the Tethyan domain on the formation of petroleum systems in the Sichuan super basin and explores the enrichment pattern of natural gas.The results show that,firstly,the Sichuan Basin and its surrounding areas have experienced two unidirectional rifting-aggregation cycles triggered by the Proto-Tethys Ocean and the Paleo-Tethys Ocean during the Neoproterozoic to Triassic.During Jurassic–Cenozoic,the Sichuan Basin is incorporated in the circum-Tibetan plateau basin-mountain coupled tectonic domain system.The episodic tectonic movements within the plate control the sedimentary infill styles.Second,the evolution of the Tethyan domain,paleoclimatic environment and major geological events controlled the formation and distribution of high-quality source rocks within the basin.The rift valley and intracratonic rift,passive continental margin slope,and intracratonic sags are favorable areas for the development of source rocks.Third,the evolution of the Tethyan domain,supercontinent cycles,global sea level changes,and tectono-climatic events controlled the distribution of carbonate platform and reservoir-caprock combinations.The cratonic platform margins and sub-platform internal high terrains are key areas for finding carbonate high-energy facies belts.Syndepositional paleo-uplifts and surrounding slopes,regional unconformities,and later faults zone are areas where large-scale carbonate reservoirs are distributed.The regional evaporite or shale caprock are beneficial for the large-scale preservation of oil and gas in the basin.Fourth,the spatio-temporal matching relationship of reservoir forming factors influenced by the early tectonic-sedimentary evolution pattern and the degree of later tectonic modification is the key to oil and gas enrichment.Future oil and gas exploration should focus on potential gas systems during the Sinian rift period,Cambrian pre-salt gas systems in the eastern and southern Sichuan,as well as whole oil and gas systems of Permian and Triassic.
文摘Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise.
基金supported by the National Natural Science Foundation of China(Grant Nos.41076072 and 40676025)
文摘Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous （more than 70.0 Ma）. There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi｜s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene （E/O） tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.
基金supported by the National Key R&D Program of China,focused special funding[grant number 2017YFC0601203].
文摘The zircon U-Pb chronology database provides a good opportunity to obtain important zircon growth peak periods in the Earth’s history so as to study the origin and evolution of the crust.It should be noted that research preference affects the objectivity of zircon sampling,leading to hot data in the database and age statistics.To evaluate the influence of hot data on statistical results,the W and Y indexes are introduced.Using a Gaussian model of multipeak fitting of zircon U-Pb age frequencies,we identify seven major growth peaks in zircons from the Chinese continental crust,which are 2498.95,1855.82,828.88,444.29,249.46,131.96,and 58.21 Ma.Due to differences in the time scales of zircon growth peaks,these peaks can be divided into two categories:first-order zircon growth peaks(Ⅰ)and second-order zircon growth peaks(Ⅱ),which represent longer and shorter time scales,perhaps due to different kinds of geological dynamics,respectively.In addition,there are clear correspondences between these ages and various geological events recognized by most scholars,namely,the Wutai orogeny,Lvliang orogeny,Jinning orogeny,Caledonian orogeny,Indosinian orogeny,Yanshanian orogeny,and Himalayan orogeny,respectively.
文摘The present review is aimed at correlating major geologic events of the Cauvery Basin with analogous global episodes. The Cauvery Basin came into existence due to Gondwana break up during Late Jurassic-Early Cretaceous by taphrogenic rift process. The first marine transgression close to Aptian/Albian boundary at the western margin of the basin terminates the syn-rift tectonic phase, which is also precise in adjoining Krishna-Godavari （KG） Basin. Two regional tectonic episodes are well documented in the basin which have global significance viz. （1） A major basinal uplift during late Turonian caused by Marion hot mantle plume resulted in widespread subaqueous volcanism in the southern part of the Cauvery Basin. This uplift also ted to relative sea level （RSL） fall of about 100 m in Cauvery and KG Basins and an unconformity of a magnitude of 2.3 Ma. The RSL fatt closely correlates with global sea level faU. This volcanic episode also resulted in Madagascar detachment from India. （2） The reunion hot mantle plume that ted to Deccan volcanism in central India resulted in E-SE tilt of the Cauvery Basin during upper Maastrichtian （CFI-CF3 zones）. This tilt caused a sea level fall of about 80 m and lateral withdrawal of sea by about 50 km developing a major erosional unconformity ranging in magnitude of -1.8-30 My. The magnitude of RSL correlates wetl with global sea level fall. This sea level fall caused widespread development of canyon features in the Cauvery Basin resulting in differential subaqueous erosion. The globally significant ocean anoxic events viz. OAE-Ib, OAE-1d, OAE-2 and OAE-3 are fairly discernible in the Cauvery Basin. The new isotopic palaeotemperature data suggests that southern India and Madagascar were located apparently in middle latitudes within the tropical-subtropical climatic zone during Atbian and early Maastrichtian. The magnitude of hiatus across K-Pg boundary varying from 0 to 30 Ma is estimated based on ptanktic foraminifera for subsurface sections. The magnetostratigraphy of outcrop sediments with rich fossil evidences reveals that magnetic polarity reversals consist of 13 mag- netozones in the Late Cretaceous sedimentary strata.
文摘The geological evolution of Australia is closely linked to supercontinent cycles that have characterised the tectonic evolution of Earth,with most geological and metallogenic events relating to supercontinent/supercraton assembly and breakup.Australia mainly grew from W–E,with two major Archean cratons,the Yilgarn and Pilbara cratons,forming the oldest part of the continent in the West Australian Element.The centre of the continent consists of the mainly Paleoproterozoic–Mesoproterozoic North and South Australian elements,whereas the E is dominated by the Neoproterozoic–Mesozoic Tasman Element.The West,North and South Australian elements initially assembled during the Paleoproterozoic amalgamation of Nuna,and the Tasman Element formed mostly as a Paleozoic accretionary margin during the assembly of Gondwana-Pangea.Australia’s present position as a relatively stable continent resulted from the breakup of Gondwana.Australia is currently moving northward toward SE Asia,probably reflecting the earliest stages of the assembly of the next supercontinent,Amasia.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0503100)the National Natural Science Foundation of China(Grant No.42202264)+2 种基金the National Natural Science Foundation of China-Academic Divisions of Chinese Academy of Sciences Frontier Interdisciplinary Research Strategic Research Joint Funding Project(Grant No.L2224032,XK2022DXC004)the Key Research Program of the Chinese Academy of Sciences,(Grant No.KGFZD-145-2023-15)Guizhou Provincial Science and Technology Projects(Grant No.[QKHJC-ZK(2023)-478]).
文摘The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal thickness,topography,and distribution of structures.However,the interpreted boundaries demarcated by different features varied widely.As research progresses,the understanding of the lunar structure is continuously improving,and new types of structures are constantly being discovered.The previous structural classification system needs to be updated.According to the major geological events and dynamic evolution,the evolutionary history of the Moon can be divided into 3 stages and 1 pivotal event.The first stage(4.52 to 4.3 Ga)is the evolution of the magmatic ocean,and it was dominated by endogenic processes.The formation of South Pole-Aitken(SPA)basin(~4.3 Ga)is the pivotal event of crustal evolution and indicates that the lunar crust had cooled and consolidated to sufficient rigidity to preserve structures.Both endogenic and exogenic processes were active in the second stage(4.3 to 3.0 Ga),which results in numerous impact basins,mare basalt flooding,and different types of associated structures.The last stage(3.0 Ga to the present)is late neotectonic activity,which has weak modification of the tectonic framework.Response of tectonic framework and structure to lunar major geological events had been organized and discussed in this paper,and key scientific issues are summarized.This study can provide reference and support for implementation of subsequent lunar exploration projects.
