Geochronology and Geochemistry of Ore-related Granitoids in the Giant Gariatong Rb Deposit,Tibet and Implications for Rb Metallogeny in China

Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet.Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization.LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1±0.2 Ma and 19.0±0.2 Ma for greisenized monzogranite and fresh monzogranite,respectively.The monzogranites are characterized as strongly peraluminous,with high contents of SiO2,Al2O3,K2O and Na2O as well as a high differentiation index.They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high fieldstrength elements.Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites,derived from remelting of crustal materials in a post-collisional setting.The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution.The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.

A Novel Three-stage Tectonic Model for Mississippi Valleytype Zn-Pb Deposits in Orogenic Fold-and-Thrust Belts

Mississippi Valley-type(MVT) Zn-Pb deposits predominantly form within both orogenic forelands and fold-andthrust belts, yet the mineralization process within the latter tectonic setting remains inadequately understood. This study, through a comprehensive review of MVT deposits across global fold-and-thrust belts, introduces a novel model elucidating the mineralization process in the context of tectonic belt evolution. It is demonstrated that during the stage Ⅰ, regional compression is introduced by early stages of plate convergence, causing the folding and thrusting and creating structural or lithological traps such as evaporite diapirs and unconformity-related carbonate dissolution-collapse structures. Thereafter, in stage Ⅱ, hydrocarbons begin to migrate and accumulate within these traps, where reduced sulfur is generated through thermochemical or bacterial sulfate reduction concurrent with or preceding Zn-Pb mineralization. In the subsequent stage Ⅲ, as plate convergence persists, the regional stress transitions from compression to transpression or extension. Under these conditions, steeply-dipping extensional faults are generated, facilitating the ascent of metalliferous brines into early-formed structural or lithological traps. Precipitation of Zn and Pb sulfides occurs through the mixing of Zn-Pb-transporting fluids with pre-existing reduced sulfur or by interaction with hydrocarbons.

Phanerozoic Tectonic Evolution,Metallogenesis and Formation of Mineral Systems in China

The continental Asia is mainly composed of three major tectonic regimes,the Tethys,Paleo Asian Ocean,and West Pacific.It underwent multi-stage plate convergences,ocean-continent transformations,and subductions,collisions and/or collages,and post collisional(orogenic)extensions in Phanerozoic.Tectonic evolution of the Asia brings up a unique fault system and tectonic geomorphological features in the China's Mainland.Also,it provides a geodynamic background for the formation and evolution of metallogeneses and mineral systems,resulting in nonuniform distribution of tectono-metallogenic systems and metallogenic belts.The spatiotemporal distribution of mineral deposits in China and adjacent areas exhibits periodic variation under controlling of the full life Wilson cycle and tectonic evolution,forming the plate convergence-related mineral system in East Asia.Porphyry Cu deposits are mainly related to compressional systems in Paleozoic and early Mesozoic,and more closely related to post-collision extensional settings in late Mesozoic and Cenozoic.Orogenic Au deposits mainly formed in post-orogeny extensional setting.Alkaline rock related rare earth element deposits formed mainly at margins of the North China and Yangtze cratons.Granite-pegmatite Li and other rare metal deposits formed mainly in early Mesozoic,related to Indosinian post-orogeny extension.Tectono-metallogenic systems provide important basis for the prospecting of mineral resources.

Occurrence of Mafic Rocks within Ediacaran Strata in the Aksu Region,NW Tarim Craton,and its Geological Implications

The Tarim Craton is an ancient Precambrian continental block,and detailed knowledge of its thermo-tectonic history is crucial for understanding the early history of continental evolution.Abundant layered mafic rocks,which have commonly been regarded as basalts,occur within the Ediacaran Sugetbrak Formation(Fm.)in the Aksu region of the northwestern Tarim Craton.Clear intrusive features have now been discovered,including mafic rocks truncating Ediacaran sedimentary layers,exhibiting an intrusion-baked margin where they interact with both the overlying and bottom wall rocks,and displaying a fine-grained transition zone from their interior to their margins.The new findings demonstrate that these mafic rocks within the Aksu Ediacaran strata were not erupted basalts but instead are intrusive diabase dykes.Therefore,these mafic rocks cannot be used to constrain the timing of the Sugetbrak Fm.in the Aksu area,nor as marker layers for regional stratigraphic correlation.Furthermore,the Ediacaran thermo-tectonic evolution in this region,deduced from the assumption that the mafic rocks are lavas,needs to be revised.

The Weixi High-silica Granitoids in the Central Sanjiang Orogenic Belt,Southwest China:Implications for Growth of the Continental Crust

High-silica granitoids record the formation and evolution of the continental crust.A new intrusive complex has been recognized among silicic volcanic rocks of the Weixi arc,Southwest China.The intrusions consist of granites,granitic porphyries,and granodiorites.Zircon U-Pb age data indicate that the Weixi granitoids formed at 248-240 Ma and were coeval with silicic volcanic rocks of the Weixi arc.The Weixi granitoids are enriched in Rb,Th,and U,depleted in Ba,Sr,Nb,Ta,and Ti,and have high light/heavy rare earth element ratios and slightly negative Eu anomalies.The Weixi granitoids have negative ε_(Nd)(t)values(-9.8 to-7.8)and negative zircon ε_(Hf)(t)values(-12.02 to-5.11).The geochemical and isotopic features suggest the Weixi granitoids were derived by partial melting of ancient crustal material.The Weixi granitoids and silicic volcanic rocks were derived from the same magma by crystal accumulation and melt extraction,respectively,and they record the formation of a continental arc in the central Sanjiang orogenic belt.

DEEP-2024 Expanded Abstract Volume

Deep Earth exploration is a multi-disciplinary, complex activity aimed at understanding the structure, dynamics and evolution of the continents and their margins. Interaction between Earth's tectonic plates created the continents and oceans that characterise our planet, while forming the mineral and other resources that support our living lives in modern society. Active tectonic processes are also responsible for devastating hazards such as earthquakes and volcanic eruptions, and control Earth's surface topography which fundamentally affects the climate and environment. Therefore, it is of common interest to society worldwide to study the interior of the Earth and to gain fundamental insight into how our planet operates.

Assessing the effects of model parameter assumptions on surface-wave inversion results

Surface-wave inversion is a powerful tool for revealing the Earth's internal structure.However,aside from shear-wave velocity(v_(S)),other parameters can influence the inversion outcomes,yet these have not been systematically discussed.This study investigates the influence of various parameter assumptions on the results of surface-wave inversion,including the compressional and shear velocity ratio(v_(P)/v_(S)),shear-wave attenuation(Q_(S)),density(ρ),Moho interface,and sedimentary layer.We constructed synthetic models to generate dispersion data and compared the obtained results with different parameter assumptions with those of the true model.The results indicate that the v_(P)/v_(S) ratio,Q_(S),and density(ρ) have minimal effects on absolute velocity values and perturbation patterns in the inversion.Conversely,assumptions about the Moho interface and sedimentary layer significantly influenced absolute velocity values and perturbation patterns.Introducing an erroneous Mohointerface depth in the initial model of the inversion significantly affected the v_(S) model near that depth,while using a smooth initial model results in relatively minor deviations.The assumption on the sedimentary layer not only affects shallow structure results but also impacts the result at greater depths.Non-linear inversion methods outperform linear inversion methods,particularly for the assumptions of the Moho interface and sedimentary layer.Joint inversion with other data types,such as receiver functions or Rayleigh wave ellipticity,and using data from a broader period range or higher-mode surface waves,can mitigate these deviations.Furthermore,incorporating more accurate prior information can improve inversion results.

Source Enrichment Control on the Scale of Magmatic-Hydrothermal W-Sn Mineralization:Insights from Triassic and Jurassic Magma Reservoirs in the Continental Crust,Xitian,South China

There are two factors,source composition and magmatic differentiation,potentially controlling W-Sn mineralization.Which one is more important is widely debated and may need to be determined for each individual deposit.The Xitian granite batholith located in South China is a natural laboratory for investigating the above problem.It consists essentially of two separate components,formed in the Triassic at ca.226 Ma and Jurassic at ca.152 Ma,respectively.The Triassic and Jurassic rocks are both composed of porphyritic and fine-grained phases.The latter resulted from highlydifferentiated porphyritic ones but they have similar textural characteristics and mineral assemblages,indicating that they reached a similar degree of crystal fractionation.Although both fine-grained phases are highly differentiated with elevated rare metal contents,economic W–Sn mineralization is rare in the Triassic granitoids and this can be attributed to less fertile source materials than their Jurassic counterparts,with a slightly more enriched isotopic signature and whole-rockεNd(226 Ma)of−10.4 to−9.2(2σ=0.2)compared withεNd(152 Ma)of−9.2 to−8.2(2σ=0.2)for the Jurassic rocks.The initial W-Sn enrichment was derived from the metasedimentary rocks and strongly enhanced by reworking of the continental crust,culminating in the Jurassic.

A review of geophysical studies on the Mongolian Plateau

The Mongolian Plateau in Central Asia is an intracontinental tectonic system far from active plate boundaries.Despite its distance from these boundaries,the plateau is characterized by intense crustal deformation accompanied by voluminous Cenozoic volcanism and active modern seismicity.However,the intraplate deformation mechanism has long been debated owing to the scarcity of observations and contradictions between different results.In recent years,growing geophysical studies have been conducted on the Mongolian Plateau,providing constraints on its lithospheric structure and dynamics.Here,we review the geophysical research on the Mongolian Plateau over the last decade,including seismological,geodetic,gravity,magnetotelluric,and geodynamic aspects.This review aims to(a)describe crustal and mantle structures based on multiscale seismic images;(b)describe deformation patterns based on seismic anisotropy,focal mechanisms,and global positioning system(GPS)observations;and(c)discuss the mechanisms behind intraplate deformation,volcanism,and seismic activity across the Mongolian Plateau.Seismic images show that the crustal structure of the plateau has significant east-west differences.Several blocks in the western Mongolian Plateau have thick crusts,including the Altai Mountains,Hovsgol Rift,and Hangay Dome.The lithospheric deformation across the Mongolian Plateau has strong lateral variation,with NE-SW shortening in the Altai Mountains and W-E or NW-SE shear deformation in the Hangay Dome region and the eastern part.The varied deformation may result from the superposition of multiple mechanisms,including far-field stress in the Altai Mountains,mantle upwelling,and mantle flow in the Hangay Dome region.However,it is difficult to identify the geodynamics of the formation of the entire Mongolian Plateau because the deformation is too complicated,and the present models are not sufficient and are always partial.Overall,this review encompasses recent advances in seismic observations of the Mongolian Plateau,illuminates the heterogeneities in the crust and mantle structure and deformation of the plateau,and discusses the mechanisms behind the deformation,magmatism,and seismicity.

Texture and Geochemistry of Multi-stage Hydrothermal Scheelite in the Mamupu Cu-Au-Mo(-W)Deposit,Eastern Tibet:Implications for Tungsten Mineralization in the Yulong Belt

Multistage tungsten mineralization was recently discovered in the Mamupu copper-polymetallic deposit in the southern Yulong porphyry copper belt(YPCB),Tibet.This study reports the results of cathodoluminescence,trace element and Sr isotope analyses of Mamupu scheelite samples,undertaken in order to better constrain the mechanism of W mineralization and the sources of the ore-forming fluids.Three different types of scheelite are identified in the Mamupu deposit:scheelite A(Sch A)mainly occurs in breccias during the prograde stage,scheelite B(Sch B)forms in the chlorite-epidote alteration zone in the retrograde stage,while scheelite C(Sch C)occurs in distal quartz sulfide veins.The extremely high Mo content and negative Eu anomaly in Sch A represent high oxygen fugacity in the prograde stage.Compared with ore-related porphyries,Sch A has a similar REE pattern,but with higher ΣREE,more depleted HREE and slightly lower(^(87)Sr/^(86)Sr)i ratios.These features suggest that Sch A is genetically related to ore-related porphyries,but extensive interaction with carbonate surrounding rocks affects the final REE and Sr isotopic composition.Sch B shows dark(Sch B-I)and light(Sch B-II)domains under CL imaging.From Sch B-I to Sch B-II,LREEs are gradually depleted,with MREEs being gradually enriched.Sch C has the highest LREE/HREE ratio,which indicates that it inherited the geochemical characteristics of fluids after the precipitation of HREE-rich minerals,such as diopside and garnet,in the early prograde stage.The Mo content in Sch B and Sch C gradually decreased,indicating that the oxygen fugacity of the fluids changed from oxidative in the early stages to reductive in the later,the turbulent Eu anomaly in Sch B and Sch C indicating that the Eu anomaly in the Mamupu scheelite is not solely controlled by oxygen fugacity.The extensive interaction of magmatic-hydrothermal fluids and carbonate provides the necessary Ca^(2+)for the precipitation of scheelite in the Mamupu deposit.

Neotectonics around the Ordos Block,North China

The Eurasian continent was subject to multiphase intensive intracontinental deformation in the Cenozoic(Fig.1A).However,its Cenozoic intra-continental deformation process and the driving force has long been disputed,which is only associated with the Indo-Asian collision(Molnar and Tapponnier,1975;Jolivet et al.,1990;Tapponnier et al.,2001;Yin,2010;Xu et al.,2013;Zhao et al.,2016),is caused by the Pacific-Asian collision(Cui,1997;Schellart and Lister,2005;Fan et al.,2019),or is connected with a combined effect of the Indo-Asian collision and the Pacific-Eurasia convergence(Ren et al.,2002;Li et al.,2013;Shi et al.,2015;Liu et al.,2019).

An Overview on the Composition and Age of Upper Crust of Proto-Tethyan Lajishan Intra-oceanic Arc,NE Tibet Plateau

Identification and anatomy of oceanic arcs within ancient orogenic belt are significant for better understanding the tectonic framework and closure process of paleo-ocean basin.This article summarizes the geological,geochemical,and geochronological characteristics of upper crust of Proto-Tethyan Lajishan intra-oceanic arc and provides new data to constrain the subduction evolution of the South Qilian Ocean.The intra-oceanic arc volcanic rocks,including intermediate-mafic lava,breccia,tuff,and minor felsic rocks,are distributed along southern part of the Lajishan ophiolite belt.Geochemical and isotopic compositions indicate that the intermediate-mafic lava were originated from depleted mantle contaminated by sediment melts or hydrous fluids,whereas the felsic rocks were likely generated by partial melting of juvenile mafic crust in intra-oceanic arc setting.Zircons from felsic rocks yield consistent and concordant ages ranging from 506 to 523 Ma,suggesting these volcanic rocks represent the relicts of upper crust of the Cambrian intra-oceanic arc.Combined with the Cambrian forearc ophiolite and accretionary complex,we suggest that the Cambrian intra-oceanic arc in the Lajishan ophiolite belt is belonging to the intra-oceanic arc system which was generated by south-directed subduction in the South Qilian Ocean at a relatively short interval between approximately 530 and 480 Ma.

Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo-Tethys Ocean

Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo-Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc-like geochemical signatures in a subduction-zone tectonic setting characterized by high Al_(2)O_(3) and low TiO_(2) contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive ε_(Nd)(t) values, and the relatively high Sr-Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo-Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.

Intrinsic and scattering attenuations of the Sichuan-Yunnan region in China from S coda waves

Seismic attenuation is a fundamental property of the Earth's media.Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied.In this study,we collected 108,399 waveforms of 11,517 local small earthquakes with magnitudes between 1.5 and 3.5 from January 2014 to September 2021 in the Sichuan-Yunnan region and its adjacent areas.We employed an envelope inversion technique for separating the intrinsic and scattering attenuations of the S coda wave,and obtained the intrinsic and scattering attenuation structures for frequencies between 0.25 and 8.00 Hz.The attenuation structures correlate well with the geological units,and some major faults mark the attenuation variations where historic large earthquakes have occurred.The regional average attenuation shows a negative frequency dependence.The average scattering attenuation has a faster descending rate than the average intrinsic attenuation,and is dominant at low frequencies,while at high frequencies the average intrinsic attenuation is stronger.The lateral variation in the intrinsic attenuation is consistent with the variation in heat flow,the scattering attenuation may be related to the scatter distribution and size.The total attenuation is consistent with the previous studies in this region,and the separate intrinsic and scattering attenuation may be useful in understanding regional tectonics and important in earthquake prevention and disaster reduction.

Moment magnitudes of two large Turkish earthquakes on February 6,2023 from long-period coda

Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential information for scientific research and public awareness.There are obvious discrepancies among the results that have been reported so far,which may be revised and updated later.Here we applied a novel and reliable long-period coda moment magnitude method to the two large earthquakes.The moment magnitudes(with one standard error)are 7.95±0.013 and 7.86±0.012,respectively,which are larger than all the previous reports.The first mainshock,which matches the largest recorded earthquakes in the Turkish history,is slightly larger than the second one by 0.11±0.035 in magnitude or by 0.04 to 0.18 at 95%confidence level.

New Insights into the Mesozoic Large-scale Intra-plate Magmatism and Mineralization in South China from Seismic Tomography

A great amount of new S-wave data has been combined to image the mantle structure down to lower mantle depth near the southeastern margin of Eurasia and understand the tectonics in South China since the Mesozoic.Our results reveal a large-scale structure beneath the South China Sea,with a prominent,broad low-velocity feature of at least 1500-km wide in and below the mantle transition zone(MTZ)and a pronounced low-velocity feature of nearly 500-km wide in the lowermost mantle.Together these features may represent the head-and-tail of an upwelling mantle plume that has interacted with and deformed by the subducting plates in the region.The Andaman-Sumatra plate is seen subducting steeply without stagnation in the MTZ over the large-scale low-velocity structure,suggesting that the upwelling mantle may have exerted significant influence on the overlying plate tectonics.Our results suggest a long-term extensional regime near the southeastern margin of Eurasia,which may help to understand the formation of the large-scale intra-plate magmatism and mineralization with accumulation of huge amount of rare metal elements in South China during the Mesozoic,and the continental breakup,the southeastward extrusion of Indochina,and the opening of the South China Sea during the Cenozoic.

A deep-learning-based approach for seismic surface-wave dispersion inversion(SfNet)with application to the Chinese mainland

Surface-wave tomography is an important and widely used method for imaging the crust and upper mantle velocity structure of the Earth.In this study,we proposed a deep learning(DL)method based on convolutional neural network(CNN),named SfNet,to derive the vS model from the Rayleigh wave phase and group velocity dispersion curves.Training a network model usually requires large amount of training datasets,which is labor-intensive and expensive to acquire.Here we relied on synthetics generated automatically from various spline-based vS models instead of directly using the existing vS models of an area to build the training dataset,which enhances the generalization of the DL method.In addition,we used a random sampling strategy of the dispersion periods in the training dataset,which alleviates the problem that the real data used must be sampled strictly according to the periods of training dataset.Tests using synthetic data demonstrate that the proposed method is much faster,and the results for the vS model are more accurate and robust than those of conventional methods.We applied our method to a dataset for the Chinese mainland and obtained a new reference velocity model of the Chinese continent(ChinaVs-DL1.0),which has smaller dispersion misfits than those from the traditional method.The high accuracy and efficiency of our DL approach makes it an important method for vS model inversions from large amounts of surface-wave dispersion data.

A comparative study of seismic tomography models of Southwest China

The margin of the Tibetan Plateau of Southwest China is one of the most seismically active regions of China and is the location of the China Seismic Experimental Site(CSES).Many studies have developed seismic velocity models of Southwest China,but few have compared and evaluated these models which is important for further model improvement.Thus,we compared six published seismic shear-wave velocity models of Southwest China on absolute velocity and velocity perturbation patterns.The models are derived from different types of data(e.g.,surface waves from ambient noise and earthquakes,body-wave travel times,receiver functions) and inversion methods.We interpolated the models into a uniform horizontal grid(0.5° × 0.5°) and vertically sampled them at 5,10,20,30,40,and 60 km depths.We found significant differences between the six models.Then,we selected three of them that showed greater consistency for further comparison.Our further comparisons revealed systematic biases between models in absolute velocity that may be related to different data types.The perturbation pattern of the model is especially divergent in the shallow part,but more consistent in the deep part.We conducted synthetic and inversion tests to explore possible causes and our results imply that systematic differences between the data,differences in methods,and other factors may directly affect the model.Therefore,the Southwest China velocity model still has considerable room for improvement,and the impact of inconsistency between different data types on the model needs further research.Finally,we proposed a new reference shear-wave velocity model of Southwest China(SwCM-S1.0) based on the three selected models with high consistency.We believe that this model is a better representation of more robust features of the models that are based on different data sets.

Quality influencing factors of dispersion curves from short period dense arrays based on a convolutional neural network across the north section of the Xiaojiang fault area

The number of dispersion curves increases significantly when the scale of a short-period dense array increases.Owing to a substantial increase in data volume,it is important to quickly evaluate dispersion curve quality as well as select the available dispersion curve.Accordingly,this study quantitatively evaluated dispersion curve quality by training a convolutional neural network model for ambient noise tomography using a short-period dense array.The model can select high-quality dispersion curves that exhibit a≤10%difference between the results of manual screening and the proposed model.In addition,this study established a dispersion curve loss function by analyzing the quality of the dispersion curve and the corresponding influencing factors,thereby estimating the number of available dispersion curves for the existing observation systems.Furthermore,a Monte Carlo simulation experiment is used to illustrates the station-pair interval distance probability density function,which is independent of station number in the observational system with randomly deployed stations.The results suggested that the straight-line length should exceed 15 km to ensure that loss rate of dispersion curves remains<0.5,while maintaining the threshold ambient noise tomography accuracy within the study area.

Identification of carbonates with high positive carbon isotope excursion from the Liaohe Group in the northeastern North China Craton and implications for the Lomagundi-Jatuli Event

The Great Oxidation Event(GOE)during the early Paleoproterozoic represents the first significant buildup in Earth’s atmospheric oxygen and resulted in a series of significant changes in the Earth’s surface environment.Among them is the 2.22(or 2.33)–2.06 Ga Lomagundi-Jatuli Event(LJE),which is globally,the largest magnitude and longest duration,marine carbonate positive carbon isotope excursion(δ^(13)C_(V-PDB)>10‰)known.This event has attracted the attention of scholars all over the world.However,except for a high positive carbon isotope excursion(δ^(13)C_(V-PDB)>10‰)recently identified from marine carbonate rocks within the Daposhan Formation in the lower Fanhe Group(or the Sanchazi Group)in the Longgang Block in the northeast North China Craton(NCC),Paleoproterozoic carbonates in the NCC are characterized by a low-amplitude positive carbon isotope excursion(δ^(13)C_(V-PDB)<5‰).This feature is significantly different from the high positive carbon isotope excursion characteristics of carbonates deposited during the LJE period in other cratons.To determine whether there are large-scale and reliable sedimentary records of the LJE in the NCC and the reasons for the low positive δ^(13)C excursion of the Paleoproterozoic carbonates obtained by the previous studies,we conducted field investigations,carbon-oxygen isotopes,and whole-rock major and trace element geochemical analyses of Liaohe Group carbonate rocks from the Anshan area in the northwestern margin of the Jiao-Liao-Ji Belt in the northeast NCC.Our results show that the Gaojiayu Formation of the Liaohe Group in the Anshan area has high positive δ^(13)C_(V-PDB) values from 8.6‰ to 12.4‰ and δ^(18)O_(V-SMOW) values of 17.9‰-27.4‰(δ^(18)O_(V-PDB) values ranging from−12.6‰to -3.4‰).This provides solid evidence for the preservation of reliable sedimentary records of the LJE in the northeastern NCC.Deposition of the high positive δ^(13)C excursion(>10‰)of marine carbonate rocks occurred at about 2.15 Ga.Lithological comparisons of different sections and whole-rock geochemical results show that the high positive δ^(13)C excursion is mainly controlled by the stratigraphic interval and depositional ages;the changes of sedimentary facies and diagenesis have no significant effects on reducing of the δ^(13)C values.The intrusion of mafic sills into carbonates has resulted in synchronous decrease of C-O isotopes near the contact zones,but the decreasing amplitude of δ^(13)C is less than 3‰.Therefore,our study firstly identified marine carbonates with high positive δ^(13)C excursion(>10‰)from the Gaojiayu Formation,which provides robust evidence for global correlation of the LJE,which has implications for its genesis and global significance.Moreover,due to global near-synchronization of the LJE,the carbon-oxygen isotope chemical stratigraphy of carbonate rocks deposited during the LJE period,combined with geochronological data,can provide new constraints on the stratigraphic subdivision and correlations of Paleoproterozoic sedimentary successions in the NCC.