Diamonds were formed in the mantle lithosphere,mostly at depths of 150~200km in the centres of Precambrian cratons,the buoyant ancient cores of continents.From there they were normally transported into the upper crust...Diamonds were formed in the mantle lithosphere,mostly at depths of 150~200km in the centres of Precambrian cratons,the buoyant ancient cores of continents.From there they were normally transported into the upper crust in kimberlite pipes whose diamonds are largely colourless and light yellow related to trace element N(Ia type),although brown,green,and more rarely blue-coloured diamonds are related to lattice defect and trace amounts of H,more rarely B and Ni.Pink diamonds are extremely rare in the approximately 90 diamondiferous pipes mined globally.Although small quantities have been discovered elsewhere,about 90%have been mined from the ca.1.3Ga Argyle diamond pipe in Western Australia,with the Arkhangelskaya diamond pipe in Russia the only other significant source.The pink colour at both Argyle and Arkhangelskaya is unrelated to trace elements and instead results from absorption of light from nanoscale(550nm)defects related to shear stress and plastic deformation.Macroscopically,defects are shown by glide planes,lamellae,and grain lines imposed on the originally colourless diamonds derived from their mantle source.The key question is why these defects were uniquely acquired in diamonds in the Argyle and Arkhangelskaya pipes.Unlike most diamondiferous pipes,Argyle is a rare diamondiferous volatile-rich lamproite pipe that was emplaced into the multiply deformed and rifted NNE-trending Halls Creek Orogen on the margin of the Kimberley Craton.Similarly,Arkhangelskaya in the Devonian Lomonosov kimberlite cluster is a volatile-rich low-Ti type kimberlite,a close relative to lamproite,that was emplaced into the multiply deformed Lapland-Kola Orogen on the rifted margin of the Kola Craton.These craton margins are underlain by subduction-induced volatile-enriched metasomatized mantle lithosphere in contrast to the more primeval mantle under craton centres.It is thus likely that shear stresses were exacerbated at Argyle and Arkangelskaya by rapid vertical emplacement of the anomalous volatile-enriched magmas at supercritical pressures and temperatures,that induced catastrophic phase separation of these volatiles and'mini seismic events'during rapid pressure drops during ascent from 200km depth to the surface.Such a mechanism is consistent with the presence of strongly resorbed and plastically deformed small brown industrial diamonds in the Argyle pipe.From a China perspective,it is potentially important that at 1.3Ga the alkaline Argyle pipe in northern Australia is placed adjacent to the North China Craton(NCC),with numerous world-class mineral deposits including the giant ca.1.4~1.2Ga alkaline Bayan Obo REE system on its margin.However,it is the southeastern margin of the Yangtze Craton and the Jiangnan Orogen with their lamproite pipes derived from metasomatized mantle lithosphere that present the most prospective regions for pink diamond occurrences.展开更多
The North China Craton(NCC)experienced significant lithospheric thinning of over 100 km during the Mesozoic,accompanied by extensive magmatic activity and extensional tectonics.However,the timing and mechanism of this...The North China Craton(NCC)experienced significant lithospheric thinning of over 100 km during the Mesozoic,accompanied by extensive magmatic activity and extensional tectonics.However,the timing and mechanism of this thinning remain the subjects of debate.This study presents zircon U-Pb ages,Hf isotopic data and whole-rock elemental and Sr-Nd isotopic compositions of the Guanshui monzonites and diorites in the eastern NCC.Zircon U-Pb dating reveals that both rock types formed at ca.130 Ma.The monzonites,characterized by high Mg^(#)(50.9-57.9),low Nb/U ratios(2.53-3.89)and depleted isotopic compositions,suggest derivation from asthenospheric mantle modified by slab-derived fluids.The diorites,distinguished by low SiO_(2)(49.5-50.8),high Mg^(#)(66.7-68.5)and an EM2-type enriched mantle isotopic signature,point to a lithospheric mantle source modified by subducted sediment melts.The coexistence of monzonites and diorites suggests a transition in magma source from lithospheric to asthenospheric mantle,implying that lithospheric thinning may have commenced around 130 Ma.The destruction of the NCC was likely driven by localized,small-scale drip-style detachment processes,rather than wholesale lithospheric removal.展开更多
Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric ma...Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric mantle(SCLM)beneath the northern Tan-Lu fault zone(TLFZ)during the Cenozoic.The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg^(#)olivines(89.4 to 91.2),suggesting that the regional SCLM is mainly transitional and fertile.Light rare earth element(LREE)-depleted,slightly depleted and enriched clinopyroxenes(Cpx)are identified in different peridotites.Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism.The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space.The Mesozoic–Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone.The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism,respectively.The spatial-temporal lithospheric mantle heterogeneity in composition,age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.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
Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic ...Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.展开更多
Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high...Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high-K granitoids.This study presents geochemical characteristics of high-silica(68.97 wt.%–73.99 wt.%),low-silica(58.73wt.%–69.94 wt.%),and high K_(2)O(2.77 wt.%–6.16 wt.%)contents of granitoids.Objective The data on Bundelkhand Craton’s granitic magmatism and geodynamics is not sufficiently robust.Geochemical data from this study will be used to further understand the origin,source,and petrogenesis of granitoid rocks and their implications for the evolution of geodynamics.Methodology Twenty-one samples were collected and analyzed for major,trace,and REE elements.Major elements were measured using X-ray fluorescence spectrometry(XRF),and trace and REE elements were analyzed by ICP-MS.Standard procedures from the Geological Survey of India were followed.Results The geochemical analysis presents high-silica(68.97-73.99 wt.%),low-silica(58.73-69.94 wt.%),and high K_(2)O(2.77-6.16 wt.%)contents in granitoids,classified as granite-granodiorite.The rocks are calcic to calcalkalic,magnesian,and range from peraluminous to metaluminous composition.REE patterns showed strong LREE enrichment relative to HREEs,with prominent negative Eu anomalies corresponding to earlier plagioclase fractionation.Multi-element patterns revealed negative anomalies in Nb,Sr,P,and Ti and positive anomalies in Pb.Conclusion The geochemical signatures attributed to the post-collisional magma generation and continental crustal contamination.The studied rocks show A-type and A2-type lineage,suggesting they originated from the melting of continental crust during transitional/post-collisional tectonic activity.The formation of hybrid granitoids in the Bundelkhand Craton is connected to the fractionation of hybrid magmas in shallow-seated magma chambers during these tectonic processes.展开更多
The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history...The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history of the Earth.Detailed petrography,mineral chemistry,metamorphic evolution and zircon U-Pb dating are presented for felsic granulite and two-pyroxene granulite from the Yishui complex to contribute to new insights into the Neoarchean tectonic evolution of the North China Craton.Three mineral assemblages are recognized for these granulite samples,including the prograde(M1),peak(M2)and retrograde(M3)mineral assemblages.Conventional geothermobarometry and phase equilibrium modeling yield P-T conditions of 6.5-10.9 kbar/718-839℃ for the peak metamorphism,which define a medium-pressure granulite-facies metamorphism occurred at middle to lower crust.Anticlockwise P-T paths with near-isobaric cooling(IBC)retrograde segments were reconstructed.Zircon LA-ICP-MS U-Pb dating suggests that the protolith of the felsic granulite was emplaced at 2541±7 Ma and the subsequent medium-pressure granulite-facies metamorphism occurred at 2518-2494 Ma.A two-stage mantle plume related crustal-scale sagduction geodynamic regime is proposed in the western Shandong terrane in the Neoarchean.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
The onset of the big mantle wedge(BMW)structure beneath the North China Craton remains debated.Research on the genesis of Late Mesozoic granites associated with gold deposits in the Jiaodong Peninsula above the BMW co...The onset of the big mantle wedge(BMW)structure beneath the North China Craton remains debated.Research on the genesis of Late Mesozoic granites associated with gold deposits in the Jiaodong Peninsula above the BMW could provide fresh insights into this question.The monzogranite from the Zhaoxian-Shaling gold district was intruded during 154-148 Ma.This I-type granite has high-K calc-alkaline and metaluminous characteristics.The monzogranite formed at medium temperatures(718-770℃)and was generated in a thickened lower crust at depths within the stability field of garnet.The monzogranite’s high zircon Ce^(4+)/Ce^(3+)and Eu_(N)/Eu_(N)^(*)values and low FeOT/MgO ratios,suggest that it formed in a high oxygen environment.Its variableε_(Hf)(t)values with T_(DM2)of 1.93-2.87 Ga imply that it originated from the melting of ancient crust basement,with contributions from mantle-derived materials.The granite’s enrichment in LREEs and LILEs,and depletion in HREEs and HFSEs,along with its trace element tectonic discrimination diagrams and medium Sr/Y,indicate an adakite affinity in an active continental margin setting.The transition from S-type granites to I-type granites and finally to A-type granites observed in the eastern part of North China Craton suggests a shift in the tectonic environment from compression to extension.This change is also reflected in the transition from flat subduction to steep subduction.Therefore,the monzogranite was formed in a tectonic transition setting triggered by a change in the subduction angle of the PaleoPacific Ocean slab during the Late Jurassic.This event may have marked the initiation of the BMW above the North China Craton.展开更多
The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically ass...The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.展开更多
The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,...The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.展开更多
The Central Asian Orogenic Belt(CAOB)is one of the largest and best preserved accretionary type orogenic belts in the world.Due to its complex tectonic history,the timing and location of the final closure of the Paleo...The Central Asian Orogenic Belt(CAOB)is one of the largest and best preserved accretionary type orogenic belts in the world.Due to its complex tectonic history,the timing and location of the final closure of the Paleo-Asian Ocean and its tectonic evolution have been hotly discussed.To determine the petrogenesis and tectonic characteristics of the poorly exposed Triassic volcanic-intrusive complex on the northern margin of the eastern North China Craton,the authors conducted a study of zircon Lu-Hf isotopes,integrated with zircon U-Pb dating and whole-rock geochemistry.Zircons from eight representative volcanic and intrusive samples yielded concordant U-Pb ages of 251-245 Ma.The volcanic and intrusive rocks are all characterized by enrichments in large ion lithophile elements and depletions in high field strength elements,and they have features similar to those of highly fractionated Ⅰ-type granites.TheεHf(t)values for the volcanic and intrusive rocks,respectively,range from-1.69 to+3.75(mean=+1.22)and-2.17 to+3.15(mean=+0.38),with two-stage model ages of 1035-1345 Ma(mean=1196 Ma)and 1073-1401 Ma(mean=1250 Ma).The Hf isotopic features indicate that these rocks were formed by partial melting of young crustal material that was newly accreted from the depleted mantle,together with a degree of contamination by other crustal material.The volcanic-intrusive complex was related to an active continental margin in a volcanic arc and syn-collisional setting,indicating that the Paleo-Asian Ocean was closed after the Middle Triassic(245 Ma)along the northern margin of the North China Craton.This provides a constraint on the timing of the change in tectonic setting in this area from compression to extension.The results enhance our understanding of the evolution of the Paleo-Asian Ocean.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
The mechanism of lithospheric removal and destruction of the North China Craton(NCC)has been hotly debated for decades.It is now generally accepted that the subduction of the(Paleo)-Pacific plate played an important r...The mechanism of lithospheric removal and destruction of the North China Craton(NCC)has been hotly debated for decades.It is now generally accepted that the subduction of the(Paleo)-Pacific plate played an important role in this process.However,how the plate subduction contributed to the craton destruction remains unclear.Here we report high oxygen fugacity(fO2)characteristics of the Yunmengshan granite,e.g.,hematitemagnetite intergrowth supported by zircon Ce^4+/Ce^3+ratios and apatite Mn oxygen fugacity indicator.High fO2 magmas are widely discovered in Late Mesozoic(160-130 Ma)adakitic rocks in central NCC.The origin of high fO2 magma is likely related to the input of the"oxidized mantle components",which shows a dose connection between plate subduction and destruction of the craton.The research area is^1500 km away from the current Pacific subduction zone.Considering the back-arc extension of Japan Sea since the Cretaceous,this distance may be shortened to^800 km,which is still too far for normal plate subduction.Ridge subduction is the best candidate that was responsible for the large scale magmatism and the destruction of the NCC.Massive slab-derived fluids and/or melts were liberated into an overlying mantle wedge and modified the lithospheric mantle.Rollback of the subducting plate induced the large-scale upwelling of asthenospheric mantle and triggered the formation of extensive high fO2 intraplate magmas.展开更多
The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relations...The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relationship with the host pluton. Furthermore, the coeval magmatic assemblage and its petrogenesis on the northern margin of the North China craton(NCC) are studied synthetically to elucidate their tectonic setting and the implications for the destruction of the NCC. Zircon U-Pb dating reveals that the mafic enclaves formed at 230.4 ± 2.2 Ma, which is similar to the age of the host pluton. The most basic mafic enclaves belong to weak alkaline rocks, and they display rare earth element(REE) and trace element normalized patterns and trace element compositions similar to those of ocean island basalt(OIB). In addition, they have positive εNd(t) values(+3.84 to +4.94) similar to those of the Cenozoic basalts on the northern margin of the NCC. All of these geochemical characteristics suggest that the basic mafic rocks originated from the asthenosphere. Petrological and geochemical studies suggest that the Jiefangyingzi pluton and the intermediate mafic enclaves were formed by the mixing of the asthenosphere-derived and crust-derived magmas in different degrees. The Mid-Late Triassic magmatic rocks on the northern margin of the NCC could be classified into three assemblages according to their geochemical compositions: alkaline series, weak alkaline–sub-alkaline series and sub-alkaline series rocks. Petrogenetic analyses suggest that the upwelling of the asthenosphere played an important role in the formation of these Mid-Late Triassic magmatic rocks. Basing on an analysis of regional geological data, we suggest that the northern margin of the NCC underwent destruction due to the upwelling of the asthenosphere during the Mid-Late Triassic, which was induced by the delamination of the root of the collisional orogeny between Sino-Korean and Siberian paleoplates in Late Permian.展开更多
We present crustal models for seismic P-waves(Vp),S-waves(Vs)and the Vp/Vs ratio across the southern North China Craton along latitude 36°N.Our results are based on inverse and forward modeling of long-range wide...We present crustal models for seismic P-waves(Vp),S-waves(Vs)and the Vp/Vs ratio across the southern North China Craton along latitude 36°N.Our results are based on inverse and forward modeling of long-range wide-angle reflection/refraction data.The crust of the southern Ordos Block has high lower crustal velocity(7.0 km/s)and a Moho depth of~42 km.In contrast,thick sediments and a lower average velocity(compared with the Ordos block)found underneath the Shanxi Graben are likely to be the products of rifting that has occurred since the Cenozoic.Steep Moho dips,exposed basement rock and higher average crustal velocity beneath the Lüliang Mountain and the Taihang Mountain are characteristic of an orogenic belt.The Tanlu fault and the Liaocheng-Lankao fault show sharp crustal velocity variations and a Moho offset.This seismic profile sampled the entire region of the Eastern North China Craton where the cratonic root has been destroyed and the unique crustal structure is correlated with the substantially modified lithosphere.Our crustal seismic velocity model shows a strong correspondence between surface geology,local tectonics and the deep crustal structure.展开更多
The timing and mechanisms of lithospheric thinning and destruction of the North China Craton(NCC)remain controversial,and the overall geodynamics of the process are poorly understood.This paper documents Late Triassic...The timing and mechanisms of lithospheric thinning and destruction of the North China Craton(NCC)remain controversial,and the overall geodynamics of the process are poorly understood.This paper documents Late Triassic igneous rocks including monzogranite,gabbro,and diorite from the Xiuyan District on the Liaodong Peninsula in the eastern NCC,which have LA-ICP-MS zircon U-Pb ages of 229.0±0.4 Ma,216.2±0.9 Ma,and 210.6±2.0 Ma,respectively.Monzogranite shows high-SiO_(2) adakite affinity,negative ε_(Hf)(t)values(-20.6 to-17.9),and old T_(DM2) ages(3.53-3.29 Ga),suggesting that their parental magma was derived from thickened Paleoarchean mafic lower crust and minor mantle materials that were also involved their generation.Gabbro is ultrapotassic,strongly enriched in LREEs and LILEs,depleted in HFSEs,and has evolved zircon Hf isotopes with negative ε_(Hf) of -10.04 to-5.85 and old T_(DM2) ages(2.59-2.22 Ga).These are diagnostic signatures of a crustal component,but their high contents of Mg O,Cr,Co,Ni indicate that the primary magma originated from enriched mantle.Diorite is enriched in LILEs and LREEs,depleted in HFSEs(with negative Nb,Ta,and Ti anomalies),and contains negative ε_(Hf)(t)values(-13.64 to-11.01).Compared with the gabbro,the diorite is relatively enriched in Nb,Ta and HREEs,and also contains younger T_(DM2) ages(2.11-1.94 Ga),suggesting that the diorite was formed by mixing between ancient lower crust-derived felsic magmas and asthenospheric mantle-derived magmas.Field observations,geochronology,geochemistry,and zircon Lu-Hf isotopes indicate that Late Triassic magmatism and tectonic activity resulted from deep subduction of the Yangtze Craton beneath the NCC in the Xiuyan area.This phase of tectonic activity was completed in the eastern NCC by the Late Triassic(216 Ma),and was subsequently followed by lithospheric thinning that began in the Late Triassic.展开更多
Large-scale tectonic magmatism and extensive gold mineralization have occurred in the eastern North China Craton(NCC)(Jiaodong and Liaodong peninsulas)since Mesozoic,which indicated that the region experienced decrato...Large-scale tectonic magmatism and extensive gold mineralization have occurred in the eastern North China Craton(NCC)(Jiaodong and Liaodong peninsulas)since Mesozoic,which indicated that the region experienced decratonization process.The genesis type of granites evolved from S-type to I-type and A-type during Late Jurassic to Early Cretaceous,and thus reflects the evolution of geodynamics in the Late Mesozoic,indicating the varied subduction process of the Paleo-Pacific Plate(PPP)and the craton destruction.The evolution of geochemical features shows that the mantle beneath the Jiaodong Peninsula evolved from EM-II in Jurassic to EM-I in Early Cretaceous,demonstrating that the mantle switched from enriched to depleted.The gold of decratonic gold deposits in Jiaodong Peninsula mainly comes from the lithospheric mantle domains metasomatized by fluids derived from the metamorphism and dehydration of the subducted slab in the mantle transition zone.The rapid decomposition of minerals leads to the concentrated release of ore-forming fluids,and this process leads to the explosive gold mineralization during the craton destruction.Extensive magmatic uplift and extensional structures,triggered by the craton destruction in Early Cretaceous formed the extensional tectonic system,providing space for the decratonic gold deposits in Jiaodong Peninsula.展开更多
We studied an Archean mafic dike in the TransNorth China Orogen of the North China Craton, which has a magmatic age of 2701 ± 83 Ma and is currently the oldest mafic dike in the North China Craton. Such an old di...We studied an Archean mafic dike in the TransNorth China Orogen of the North China Craton, which has a magmatic age of 2701 ± 83 Ma and is currently the oldest mafic dike in the North China Craton. Such an old dike is extremely rare in the world. The presence of mafic dikes indicates that the North China Craton was in a tensional tectonic environment at 2.7 Ga. Geochemical characteristics reveal that this mafic dike belongs to continental tholeiitic basalt. Results from Hf isotope analysis reveal that the mafic dike originates from a depleted mantle. The plate assembly in the North China landmass was realized during the Archean era(2.7 Ga), and a thick and stable continental crust was formed. Therefore, the first cratonization of the North China Craton was completed before 2.7 Ga. The intrusion of the 2.7-Ga-old mafic dike from the deep lithospheric mantle of the continent indicates that the North China Craton has undergone a period of extensional tectonic activity. This event marks a significant extensional event that occurred after the cratonization of the North China Craton.展开更多
The Bikou volcanic terrane is predominated by subalkaline tholeiitic lavas. Rock samples display lower initial ratios of Sr and Nd, 0.701248-0.704413 and 0.511080-0.512341 respectively. 207Pb and 208Pb are significant...The Bikou volcanic terrane is predominated by subalkaline tholeiitic lavas. Rock samples display lower initial ratios of Sr and Nd, 0.701248-0.704413 and 0.511080-0.512341 respectively. 207Pb and 208Pb are significantly enriched in the lavas. Most samples have positive εNd, which indicates that the magma was derived from EM-type mantle source, while a few samples with negative εNd indicate that there was contamination in the magma evolution. Magma differentiation is demonstrated by variations of LREE and LILE from depletion to enrichment. Additionally, normalized REE patterns and trace elements showed that lavas from the Bikou volcanic terrane have similar characteristics to those of basalts in arc settings caused by subduction and collision. Analyses showed that the Bikou volcanic terrane is a volcanic arc. New evidence proved that the Hengdan Group, north of the Bikou arc, is a turbidite terrane filling a forearc basin. Consequently, the Bikou volcanic terrane and the Hengdan turbidite terrane construct an arc-basin system. New SHRIMP ages showed that this arc-basin system developed on the northern margin of the Yangtze craton in the Neoproterozoic (846-776 Ma), and this arc-basin system is in agreement with the tectonic processes of Rodinia in the Neoproterzoic.展开更多
文摘Diamonds were formed in the mantle lithosphere,mostly at depths of 150~200km in the centres of Precambrian cratons,the buoyant ancient cores of continents.From there they were normally transported into the upper crust in kimberlite pipes whose diamonds are largely colourless and light yellow related to trace element N(Ia type),although brown,green,and more rarely blue-coloured diamonds are related to lattice defect and trace amounts of H,more rarely B and Ni.Pink diamonds are extremely rare in the approximately 90 diamondiferous pipes mined globally.Although small quantities have been discovered elsewhere,about 90%have been mined from the ca.1.3Ga Argyle diamond pipe in Western Australia,with the Arkhangelskaya diamond pipe in Russia the only other significant source.The pink colour at both Argyle and Arkhangelskaya is unrelated to trace elements and instead results from absorption of light from nanoscale(550nm)defects related to shear stress and plastic deformation.Macroscopically,defects are shown by glide planes,lamellae,and grain lines imposed on the originally colourless diamonds derived from their mantle source.The key question is why these defects were uniquely acquired in diamonds in the Argyle and Arkhangelskaya pipes.Unlike most diamondiferous pipes,Argyle is a rare diamondiferous volatile-rich lamproite pipe that was emplaced into the multiply deformed and rifted NNE-trending Halls Creek Orogen on the margin of the Kimberley Craton.Similarly,Arkhangelskaya in the Devonian Lomonosov kimberlite cluster is a volatile-rich low-Ti type kimberlite,a close relative to lamproite,that was emplaced into the multiply deformed Lapland-Kola Orogen on the rifted margin of the Kola Craton.These craton margins are underlain by subduction-induced volatile-enriched metasomatized mantle lithosphere in contrast to the more primeval mantle under craton centres.It is thus likely that shear stresses were exacerbated at Argyle and Arkangelskaya by rapid vertical emplacement of the anomalous volatile-enriched magmas at supercritical pressures and temperatures,that induced catastrophic phase separation of these volatiles and'mini seismic events'during rapid pressure drops during ascent from 200km depth to the surface.Such a mechanism is consistent with the presence of strongly resorbed and plastically deformed small brown industrial diamonds in the Argyle pipe.From a China perspective,it is potentially important that at 1.3Ga the alkaline Argyle pipe in northern Australia is placed adjacent to the North China Craton(NCC),with numerous world-class mineral deposits including the giant ca.1.4~1.2Ga alkaline Bayan Obo REE system on its margin.However,it is the southeastern margin of the Yangtze Craton and the Jiangnan Orogen with their lamproite pipes derived from metasomatized mantle lithosphere that present the most prospective regions for pink diamond occurrences.
基金supported by the Jiangsu Innovation and Entrepreneurship Project(JSSCBS20211225).
文摘The North China Craton(NCC)experienced significant lithospheric thinning of over 100 km during the Mesozoic,accompanied by extensive magmatic activity and extensional tectonics.However,the timing and mechanism of this thinning remain the subjects of debate.This study presents zircon U-Pb ages,Hf isotopic data and whole-rock elemental and Sr-Nd isotopic compositions of the Guanshui monzonites and diorites in the eastern NCC.Zircon U-Pb dating reveals that both rock types formed at ca.130 Ma.The monzonites,characterized by high Mg^(#)(50.9-57.9),low Nb/U ratios(2.53-3.89)and depleted isotopic compositions,suggest derivation from asthenospheric mantle modified by slab-derived fluids.The diorites,distinguished by low SiO_(2)(49.5-50.8),high Mg^(#)(66.7-68.5)and an EM2-type enriched mantle isotopic signature,point to a lithospheric mantle source modified by subducted sediment melts.The coexistence of monzonites and diorites suggests a transition in magma source from lithospheric to asthenospheric mantle,implying that lithospheric thinning may have commenced around 130 Ma.The destruction of the NCC was likely driven by localized,small-scale drip-style detachment processes,rather than wholesale lithospheric removal.
基金supported by funds from the Ministry of Science and Technology of the People's Republic of China(No.2019YFA0708603)NSFC(Nos.41973050,42288201,41930215)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0202)。
文摘Mineralogical data are presented for the peridotite xenoliths from Miocene(~19 Ma)Qingyuan basalts in the eastern North China Craton(NCC),with the aim of constraining on property of the sub-continental lithospheric mantle(SCLM)beneath the northern Tan-Lu fault zone(TLFZ)during the Cenozoic.The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg^(#)olivines(89.4 to 91.2),suggesting that the regional SCLM is mainly transitional and fertile.Light rare earth element(LREE)-depleted,slightly depleted and enriched clinopyroxenes(Cpx)are identified in different peridotites.Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism.The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space.The Mesozoic–Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone.The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism,respectively.The spatial-temporal lithospheric mantle heterogeneity in composition,age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.
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financially supported by the National Natural Science Foundation of China(Grant No.41902224,41602209).
文摘Detrital zircon and apatite U-Pb-Hf isotope and trace element analyses of the late Mesoproterozoic to early Neoproterozoic strata in southern Jilin provide detailed information on the sediment provenance and tectonic setting of the northeastern margin of the North China Craton(NCC).Here,we present U-Pb and Lu-Hf analyses of 712 detrital zircons,and U-Pb analyses of 347 detrital apatites from the Baifangzi,Diaoyutai and Qiaotou formations.The Baifangzi and Diaoyutai formations are dominated by Neoarchean(2.5-2.6 Ga)and Paleoproterozoic(1.8-1.9 Ga)zircons,indicating a predominant NCC provenance.The Qiaotou Formation is dominated by Mesoproterozoic(1.5-1.7 Ga and 1.1-1.3 Ga)zircons with mainly positiveεHf(t)values,which are similar to those from eastern Laurentia,implying a significant provenance transition.The detrital apatite age spectra of the Baifangzi and Diaoyutai Formations show major populations at 1.8-1.9 Ga and 1.1-1.3 Ga.Based on their trace element compositions,the Mesoproterozoic apatites were mainly sourced from metamorphic rocks,indicating regional metamorphism occurred in the NCC during 1.1-1.3 Ga.Combining these data with regional studies,we propose that the NCC was adjacent to eastern Laurentia during the assembly of the Rodinia supercontinent.
基金Geological Survey of India,Northern Region have provided the financial funding for the study.
文摘Background The Bundelkhand Craton is significant for preserving the multiphase granitoids magmatism from Paleoarchean to Neoarchean periods.It consists of a variety of granite rocks,including TTGs,sanukitoids,and high-K granitoids.This study presents geochemical characteristics of high-silica(68.97 wt.%–73.99 wt.%),low-silica(58.73wt.%–69.94 wt.%),and high K_(2)O(2.77 wt.%–6.16 wt.%)contents of granitoids.Objective The data on Bundelkhand Craton’s granitic magmatism and geodynamics is not sufficiently robust.Geochemical data from this study will be used to further understand the origin,source,and petrogenesis of granitoid rocks and their implications for the evolution of geodynamics.Methodology Twenty-one samples were collected and analyzed for major,trace,and REE elements.Major elements were measured using X-ray fluorescence spectrometry(XRF),and trace and REE elements were analyzed by ICP-MS.Standard procedures from the Geological Survey of India were followed.Results The geochemical analysis presents high-silica(68.97-73.99 wt.%),low-silica(58.73-69.94 wt.%),and high K_(2)O(2.77-6.16 wt.%)contents in granitoids,classified as granite-granodiorite.The rocks are calcic to calcalkalic,magnesian,and range from peraluminous to metaluminous composition.REE patterns showed strong LREE enrichment relative to HREEs,with prominent negative Eu anomalies corresponding to earlier plagioclase fractionation.Multi-element patterns revealed negative anomalies in Nb,Sr,P,and Ti and positive anomalies in Pb.Conclusion The geochemical signatures attributed to the post-collisional magma generation and continental crustal contamination.The studied rocks show A-type and A2-type lineage,suggesting they originated from the melting of continental crust during transitional/post-collisional tectonic activity.The formation of hybrid granitoids in the Bundelkhand Craton is connected to the fractionation of hybrid magmas in shallow-seated magma chambers during these tectonic processes.
基金supported by the Natural Science Foundation of Shandong Provence(Grant No.ZR2023MD058)National Natural Science Foundation of China(Grant Nos.42072219,41802201)。
文摘The Yishui complex,located in the western Shandong area of the North China Craton,is representative of the Archean crystalline basement of the North China Craton to explore the early tectonic-thermal evolution history of the Earth.Detailed petrography,mineral chemistry,metamorphic evolution and zircon U-Pb dating are presented for felsic granulite and two-pyroxene granulite from the Yishui complex to contribute to new insights into the Neoarchean tectonic evolution of the North China Craton.Three mineral assemblages are recognized for these granulite samples,including the prograde(M1),peak(M2)and retrograde(M3)mineral assemblages.Conventional geothermobarometry and phase equilibrium modeling yield P-T conditions of 6.5-10.9 kbar/718-839℃ for the peak metamorphism,which define a medium-pressure granulite-facies metamorphism occurred at middle to lower crust.Anticlockwise P-T paths with near-isobaric cooling(IBC)retrograde segments were reconstructed.Zircon LA-ICP-MS U-Pb dating suggests that the protolith of the felsic granulite was emplaced at 2541±7 Ma and the subsequent medium-pressure granulite-facies metamorphism occurred at 2518-2494 Ma.A two-stage mantle plume related crustal-scale sagduction geodynamic regime is proposed in the western Shandong terrane in the Neoarchean.
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 Geological Survey Program of Shandong Province(Yingpeng Wang)Yunnan Fundamental Research Projects(Yongbin Wang)。
文摘The onset of the big mantle wedge(BMW)structure beneath the North China Craton remains debated.Research on the genesis of Late Mesozoic granites associated with gold deposits in the Jiaodong Peninsula above the BMW could provide fresh insights into this question.The monzogranite from the Zhaoxian-Shaling gold district was intruded during 154-148 Ma.This I-type granite has high-K calc-alkaline and metaluminous characteristics.The monzogranite formed at medium temperatures(718-770℃)and was generated in a thickened lower crust at depths within the stability field of garnet.The monzogranite’s high zircon Ce^(4+)/Ce^(3+)and Eu_(N)/Eu_(N)^(*)values and low FeOT/MgO ratios,suggest that it formed in a high oxygen environment.Its variableε_(Hf)(t)values with T_(DM2)of 1.93-2.87 Ga imply that it originated from the melting of ancient crust basement,with contributions from mantle-derived materials.The granite’s enrichment in LREEs and LILEs,and depletion in HREEs and HFSEs,along with its trace element tectonic discrimination diagrams and medium Sr/Y,indicate an adakite affinity in an active continental margin setting.The transition from S-type granites to I-type granites and finally to A-type granites observed in the eastern part of North China Craton suggests a shift in the tectonic environment from compression to extension.This change is also reflected in the transition from flat subduction to steep subduction.Therefore,the monzogranite was formed in a tectonic transition setting triggered by a change in the subduction angle of the PaleoPacific Ocean slab during the Late Jurassic.This event may have marked the initiation of the BMW above the North China Craton.
基金funded by the National Natural Science Foundation of China(42125203,42330809)the 111 project of the Ministry of Science and Technology(BP0719021).
文摘The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.
基金National Natural Science Foundation of China,Grant/Award Number:42230812。
文摘The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.
基金supported by the National Natural Science Foundation of China(U2244213)the project from China Geological Survey(No.DD20160062)the fundamental research project from the Institute of Geomechanics,Chinese Academy of Geological Sciences(DZLXJK202307).
文摘The Central Asian Orogenic Belt(CAOB)is one of the largest and best preserved accretionary type orogenic belts in the world.Due to its complex tectonic history,the timing and location of the final closure of the Paleo-Asian Ocean and its tectonic evolution have been hotly discussed.To determine the petrogenesis and tectonic characteristics of the poorly exposed Triassic volcanic-intrusive complex on the northern margin of the eastern North China Craton,the authors conducted a study of zircon Lu-Hf isotopes,integrated with zircon U-Pb dating and whole-rock geochemistry.Zircons from eight representative volcanic and intrusive samples yielded concordant U-Pb ages of 251-245 Ma.The volcanic and intrusive rocks are all characterized by enrichments in large ion lithophile elements and depletions in high field strength elements,and they have features similar to those of highly fractionated Ⅰ-type granites.TheεHf(t)values for the volcanic and intrusive rocks,respectively,range from-1.69 to+3.75(mean=+1.22)and-2.17 to+3.15(mean=+0.38),with two-stage model ages of 1035-1345 Ma(mean=1196 Ma)and 1073-1401 Ma(mean=1250 Ma).The Hf isotopic features indicate that these rocks were formed by partial melting of young crustal material that was newly accreted from the depleted mantle,together with a degree of contamination by other crustal material.The volcanic-intrusive complex was related to an active continental margin in a volcanic arc and syn-collisional setting,indicating that the Paleo-Asian Ocean was closed after the Middle Triassic(245 Ma)along the northern margin of the North China Craton.This provides a constraint on the timing of the change in tectonic setting in this area from compression to extension.The results enhance our understanding of the evolution of the Paleo-Asian Ocean.
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National Key R&D Program of China(2016YFC0600408)Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB18020102)+1 种基金Guangdong Natural Science Funds(2014A030306032 and 2015TQ01Z611)Youth Innovation Promotion Association CAS(2016315)。
文摘The mechanism of lithospheric removal and destruction of the North China Craton(NCC)has been hotly debated for decades.It is now generally accepted that the subduction of the(Paleo)-Pacific plate played an important role in this process.However,how the plate subduction contributed to the craton destruction remains unclear.Here we report high oxygen fugacity(fO2)characteristics of the Yunmengshan granite,e.g.,hematitemagnetite intergrowth supported by zircon Ce^4+/Ce^3+ratios and apatite Mn oxygen fugacity indicator.High fO2 magmas are widely discovered in Late Mesozoic(160-130 Ma)adakitic rocks in central NCC.The origin of high fO2 magma is likely related to the input of the"oxidized mantle components",which shows a dose connection between plate subduction and destruction of the craton.The research area is^1500 km away from the current Pacific subduction zone.Considering the back-arc extension of Japan Sea since the Cretaceous,this distance may be shortened to^800 km,which is still too far for normal plate subduction.Ridge subduction is the best candidate that was responsible for the large scale magmatism and the destruction of the NCC.Massive slab-derived fluids and/or melts were liberated into an overlying mantle wedge and modified the lithospheric mantle.Rollback of the subducting plate induced the large-scale upwelling of asthenospheric mantle and triggered the formation of extensive high fO2 intraplate magmas.
基金funded by the National Key Research and Development Program of China from the Ministry of Science and Technology of China(Grant No.2017YFC0601301)National Natural Science Foundation of China(Grant No.41472055)the China Geological Survey(Grant No.DD20160201-01)。
文摘The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relationship with the host pluton. Furthermore, the coeval magmatic assemblage and its petrogenesis on the northern margin of the North China craton(NCC) are studied synthetically to elucidate their tectonic setting and the implications for the destruction of the NCC. Zircon U-Pb dating reveals that the mafic enclaves formed at 230.4 ± 2.2 Ma, which is similar to the age of the host pluton. The most basic mafic enclaves belong to weak alkaline rocks, and they display rare earth element(REE) and trace element normalized patterns and trace element compositions similar to those of ocean island basalt(OIB). In addition, they have positive εNd(t) values(+3.84 to +4.94) similar to those of the Cenozoic basalts on the northern margin of the NCC. All of these geochemical characteristics suggest that the basic mafic rocks originated from the asthenosphere. Petrological and geochemical studies suggest that the Jiefangyingzi pluton and the intermediate mafic enclaves were formed by the mixing of the asthenosphere-derived and crust-derived magmas in different degrees. The Mid-Late Triassic magmatic rocks on the northern margin of the NCC could be classified into three assemblages according to their geochemical compositions: alkaline series, weak alkaline–sub-alkaline series and sub-alkaline series rocks. Petrogenetic analyses suggest that the upwelling of the asthenosphere played an important role in the formation of these Mid-Late Triassic magmatic rocks. Basing on an analysis of regional geological data, we suggest that the northern margin of the NCC underwent destruction due to the upwelling of the asthenosphere during the Mid-Late Triassic, which was induced by the delamination of the root of the collisional orogeny between Sino-Korean and Siberian paleoplates in Late Permian.
基金supported by the DREAM project of the National Key R&D Program of China(No.2016YFC0600402)the National Natural Science Foundation of China(No.41774071)the US Gelogical Survey Earthquake Hazards Program。
文摘We present crustal models for seismic P-waves(Vp),S-waves(Vs)and the Vp/Vs ratio across the southern North China Craton along latitude 36°N.Our results are based on inverse and forward modeling of long-range wide-angle reflection/refraction data.The crust of the southern Ordos Block has high lower crustal velocity(7.0 km/s)and a Moho depth of~42 km.In contrast,thick sediments and a lower average velocity(compared with the Ordos block)found underneath the Shanxi Graben are likely to be the products of rifting that has occurred since the Cenozoic.Steep Moho dips,exposed basement rock and higher average crustal velocity beneath the Lüliang Mountain and the Taihang Mountain are characteristic of an orogenic belt.The Tanlu fault and the Liaocheng-Lankao fault show sharp crustal velocity variations and a Moho offset.This seismic profile sampled the entire region of the Eastern North China Craton where the cratonic root has been destroyed and the unique crustal structure is correlated with the substantially modified lithosphere.Our crustal seismic velocity model shows a strong correspondence between surface geology,local tectonics and the deep crustal structure.
基金supported by the project of China Geological Survey(Grant No.DD20190438)。
文摘The timing and mechanisms of lithospheric thinning and destruction of the North China Craton(NCC)remain controversial,and the overall geodynamics of the process are poorly understood.This paper documents Late Triassic igneous rocks including monzogranite,gabbro,and diorite from the Xiuyan District on the Liaodong Peninsula in the eastern NCC,which have LA-ICP-MS zircon U-Pb ages of 229.0±0.4 Ma,216.2±0.9 Ma,and 210.6±2.0 Ma,respectively.Monzogranite shows high-SiO_(2) adakite affinity,negative ε_(Hf)(t)values(-20.6 to-17.9),and old T_(DM2) ages(3.53-3.29 Ga),suggesting that their parental magma was derived from thickened Paleoarchean mafic lower crust and minor mantle materials that were also involved their generation.Gabbro is ultrapotassic,strongly enriched in LREEs and LILEs,depleted in HFSEs,and has evolved zircon Hf isotopes with negative ε_(Hf) of -10.04 to-5.85 and old T_(DM2) ages(2.59-2.22 Ga).These are diagnostic signatures of a crustal component,but their high contents of Mg O,Cr,Co,Ni indicate that the primary magma originated from enriched mantle.Diorite is enriched in LILEs and LREEs,depleted in HFSEs(with negative Nb,Ta,and Ti anomalies),and contains negative ε_(Hf)(t)values(-13.64 to-11.01).Compared with the gabbro,the diorite is relatively enriched in Nb,Ta and HREEs,and also contains younger T_(DM2) ages(2.11-1.94 Ga),suggesting that the diorite was formed by mixing between ancient lower crust-derived felsic magmas and asthenospheric mantle-derived magmas.Field observations,geochronology,geochemistry,and zircon Lu-Hf isotopes indicate that Late Triassic magmatism and tectonic activity resulted from deep subduction of the Yangtze Craton beneath the NCC in the Xiuyan area.This phase of tectonic activity was completed in the eastern NCC by the Late Triassic(216 Ma),and was subsequently followed by lithospheric thinning that began in the Late Triassic.
基金Supported by projects of the Youth Science and Technology Innovation Fund of Shandong Provincial No.6 Exploration Institute of Geology and Mineral Resources(No.LY-QK-202203)National Natural Science Foundation of China-Shandong Joint Fund(No.U2006201).
文摘Large-scale tectonic magmatism and extensive gold mineralization have occurred in the eastern North China Craton(NCC)(Jiaodong and Liaodong peninsulas)since Mesozoic,which indicated that the region experienced decratonization process.The genesis type of granites evolved from S-type to I-type and A-type during Late Jurassic to Early Cretaceous,and thus reflects the evolution of geodynamics in the Late Mesozoic,indicating the varied subduction process of the Paleo-Pacific Plate(PPP)and the craton destruction.The evolution of geochemical features shows that the mantle beneath the Jiaodong Peninsula evolved from EM-II in Jurassic to EM-I in Early Cretaceous,demonstrating that the mantle switched from enriched to depleted.The gold of decratonic gold deposits in Jiaodong Peninsula mainly comes from the lithospheric mantle domains metasomatized by fluids derived from the metamorphism and dehydration of the subducted slab in the mantle transition zone.The rapid decomposition of minerals leads to the concentrated release of ore-forming fluids,and this process leads to the explosive gold mineralization during the craton destruction.Extensive magmatic uplift and extensional structures,triggered by the craton destruction in Early Cretaceous formed the extensional tectonic system,providing space for the decratonic gold deposits in Jiaodong Peninsula.
基金supported by the open fund from the Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences (Number J1901-16)the project of graduate education and teaching reform in Shanxi Province (Number 2021YJJG147)+3 种基金the teaching reform project"Geographic Modeling,Simulation and Visualization"established by Shanxi Normal University (Number2019JGXM-39)"The Research Start-up Fund of Shanxi Normal University for Dr.Peng Chong in 2016"(Number 0505/02070438)"The Research Start-up Fund of Shanxi Normal University for Dr.Liu Haiyan in 2017"(Number 0505/02070458)"The Research Fund for Outstanding Doctor in 2017"(Number 0503/02010168),established by the Education Department of Shanxi Province for Dr.Liu Haiyan。
文摘We studied an Archean mafic dike in the TransNorth China Orogen of the North China Craton, which has a magmatic age of 2701 ± 83 Ma and is currently the oldest mafic dike in the North China Craton. Such an old dike is extremely rare in the world. The presence of mafic dikes indicates that the North China Craton was in a tensional tectonic environment at 2.7 Ga. Geochemical characteristics reveal that this mafic dike belongs to continental tholeiitic basalt. Results from Hf isotope analysis reveal that the mafic dike originates from a depleted mantle. The plate assembly in the North China landmass was realized during the Archean era(2.7 Ga), and a thick and stable continental crust was formed. Therefore, the first cratonization of the North China Craton was completed before 2.7 Ga. The intrusion of the 2.7-Ga-old mafic dike from the deep lithospheric mantle of the continent indicates that the North China Craton has undergone a period of extensional tectonic activity. This event marks a significant extensional event that occurred after the cratonization of the North China Craton.
基金supports from the National Natural Science Foundation of China(grants 40172071 and 40211120151 to Yan Quanren)the Ministry of Science and Technology of the People’s Republic of China(grant 2202CB412608 to Wang Zongqi)+2 种基金the China Geological Survey(grant DKD2001002 to Wang Zongqi)the University of Nevada Las Vegas(to Hanson)and the Geological Society of America(to Druschke)are gratefully appreciated.
文摘The Bikou volcanic terrane is predominated by subalkaline tholeiitic lavas. Rock samples display lower initial ratios of Sr and Nd, 0.701248-0.704413 and 0.511080-0.512341 respectively. 207Pb and 208Pb are significantly enriched in the lavas. Most samples have positive εNd, which indicates that the magma was derived from EM-type mantle source, while a few samples with negative εNd indicate that there was contamination in the magma evolution. Magma differentiation is demonstrated by variations of LREE and LILE from depletion to enrichment. Additionally, normalized REE patterns and trace elements showed that lavas from the Bikou volcanic terrane have similar characteristics to those of basalts in arc settings caused by subduction and collision. Analyses showed that the Bikou volcanic terrane is a volcanic arc. New evidence proved that the Hengdan Group, north of the Bikou arc, is a turbidite terrane filling a forearc basin. Consequently, the Bikou volcanic terrane and the Hengdan turbidite terrane construct an arc-basin system. New SHRIMP ages showed that this arc-basin system developed on the northern margin of the Yangtze craton in the Neoproterozoic (846-776 Ma), and this arc-basin system is in agreement with the tectonic processes of Rodinia in the Neoproterzoic.
