Abstract:Mesozoic volcanic rocks are widely developed in the Bohai Bay basin.However,the exploration of large-scale volcanic hydrocarbon reservoirs has remained a persistent challenge in deep buried-hill plays in the Bohai area.To investigate the primary controls on substantial hydrocarbon accumulation,this study focuses on the Bohai A Mesozoic volcanic rocks,which have recently achieved significant exploration breakthroughs in the Bohai Sea area,as the research target area.drilling and logging data,sidewall core and thin-section observations,petrochemical analyses combined with 3D seismic,it characterizes the lithology-facies associations,volcanic edifice types,reservoir space characteristics,and key factors governing hydrocarbon accumulation.Research has shown that the BZ-A structure develops three volcanic rock cycles from base to top:basic,intermediate,and acidic.The late stage acidic volcanic rock cycle is composed of multiple large and medium-sized acidic lava volcanic structures stacked together,and is a thick and stable distribution of rhyolite.It mainly develops three types of rock types:effusive facies including vesicular and massive rhyolites,and volcanic conduit facies represented by rhyolitic cryptoexplosive breccia,which have the lithological and lithological basis for developing high-quality volcanic rock reservoirs.Although primary porosity is limited,extensive secondary modification-driven by intense tectonic activity and multi-phase fluid dissolution—has developed abundant structural fractures and dissolution pores/fissures..The reservoir is vertically divided into a surface weathering dissolution zone and an inner crack dissolution zone with a double-layer reservoir structure,and the overall structure is a large-scale high-quality fracture solution with high porosity and permeability.The favorable factors for oil and gas accumulation in BZ-A include high porosity and permeability acidic volcanic rock fracture solution bodies,ancient uplifted anticline traps,proximity to the Bozhong hydrocarbon rich depression,overlying thick layer overpressure mudstone,and late stage weak tectonic activity.Based on these findings,a comprehensive hydrocarbon accumulation model for ultra deep,large-scale Mesozoic volcanic reservoirs is established,which offers valuable insights for volcanic hydrocarbon exploration in the Bohai Bay basin and analogous settings worldwide.

Abstract:In order to fully understand the characteristics of main source rocks and the distribution of effective source kitchen in Enping 17 sub-sag,it systematically analyzes the geological background of the depression,the development environment of hydrocarbon source rocks and the geochemical characteristics,the hydrocarbon generation characteristics of hydrocarbon source rocks by means of thermal pressure simulation experiments,establishes the TOC probability neural network prediction model of hydrocarbon source rocks,and predicts the distribution of effective source kitchen in combination with the thermal evolution simulation of hydrocarbon source rocks and the identification of the TOC lower limit of effective hydrocarbon source rocks.The results indicate that the Enping 17 sub-sag mainly develops two sets of hydrocarbon source rocks,the semi deep-deep lake and shallow lake facies of the Wenchang Formation.The oil and gas production rates of the semi deep-deep lake facies are relatively high,with the characteristics of concentrated oil generation and late explosive gas generation.Shallow lacustrine mudstone has a relatively high gas production rate and is characterized by wide window continuous gas generation and a high lower limit of gas generation.The effective source kitchen of Wenchang Formation in Enping 17 sub-sag are distributed in the areas where the TOC of source rocks is greater than 1.2%,mainly distributed in the sub-sag center and the northern near sub-sag on the plane,mainly distributed in the 4th member of Wenchang Formation vertically,followed by the 3rd and 5th member of Wenchang Formation.The facies are dominated by semi deep-deep lake facies,while the shallow lake facies source rocks are another set of important source rocks in this area.Under the high thermal evolution,oil and gas are generated simultaneously in the sub-sag,which has the development of large-scale natural gas potential,provides a resource basis for searching for natural gas in oil rich sag of the Pearl River Mouth basin.

Abstract:Aiming at the impact of dewatering in metro deep foundation pits on the deformation and safe operation of adjacent high-speed railway bridge piles,this study investigates the mechanism of pile-soil interaction under seepage-stress coupling effects and proposes effective collaborative control measures.Through field pre-dewatering tests,variations in groundwater levels and surface settlement around bridge piles under different drawdown conditions were monitored.Using Abaqus for numerical simulation,a seepage-stress coupling model was established to analyze the influence of different dewatering depths on the lateral friction resistance and neutral point position of pile foundations,with comparative analysis against field data to summarize variation patterns.As the dewatering depth increases,the disturbed seepage field gradually extends toward the pile foundation,forming a seepage flow pattern around the piles.The deformation of the pile foundation exhibits nonlinear growth,with significant increases in settlement and lateral deformation observed after exceeding a 10 m drawdown.Negative skin friction in the upper part of the pile increases,the neutral point shifts downward,and positive skin friction at the pile base enhances.The deformation of bridge piles adjacent to metro deep foundation pits during dewatering is considerably influenced by the dewatering depth.Collaborative control measures such as multi-stage dewatering,waterproof curtains,real-time water level monitoring,and recharge can be adopted to mitigate pile deformation and ensure the operational safety of high-speed railways.

Abstract:The northeastern black soil region,recognized as a critical grain-producing area in China,has experienced a continuous decline in soil organic matter(SOM)content in recent years.The application of hyperspectral remote sensing technology for SOM content retrieval plays a crucial role in assessing the current status of black soil and implementing conservation measures.To address the low retrieval accuracy resulting from scale discrepancies in spatial and spectral characteristics of black soil,this study developed a remote sensing retrieval model with multi-scale feature enhancement.By constructing a multi-scale feature enhancement structure,spectral features were systematically extracted at different scales.Furthermore,skip connections were incorporated to effectively integrate initial spectral features with deep hierarchical features derived from convolutional networks,thereby strengthening the model's spectral representation capacity.When benchmarked against traditional methods such as partial least squares regression and random forest models,the proposed model demonstrates enhanced capability in capturing multi-scale black soil features and establishing spectral relationships.This advancement enables accurate SOM content retrieval under complex conditions,providing both theoretical significance and practical value for advancing intelligent remote sensing retrieval and sustainable conservation of black soil resources.

Abstract:Under global climate warming scenarios,permafrost degradation has triggered retrogressive thaw slumps,posing threats to engineering infrastructure and ecological security in cold regions.However,many scholars lack sufficient understanding of the morphological characteristics and evolutionary processes of RTSs(retrogressive thaw slumps),and the applicability of simulation models has not been systematically summarized.In this study,RTSs from four perspectives:morphology,evolution,destabilization mechanisms,and simulation methods,based on field investigation and literature analysis.The main findings include:(1)The morphological characteristics of RTSs can be classified into 11 types,and their spatial distribution is associated with topographic features,permafrost conditions,and developmental stages.(2)The evolution of RTSs experiences four stages:surface cracking,active layer detachment,polycyclic recession,and gradual stabilization,mainly affected by ground ice and extreme climatic events.(3)The instability of RTSs is the result of the interaction among thermal-hydrological-mechanical fields.Under the influence of the stress field,moisture and heat transfer are affected,while the temperature and moisture fields determine the pore water pressure,which in turn influences the stress field and change slope stability.(4)The limit equilibrium method,numerical simulation,and uncertainty analysis are the main methods for simulating permafrost stability,each with its own advantages and limitations.This study enhances the understanding of the phenomena and processes of RTSs.It is of great significance for revealing the interaction mechanisms among permafrost,climate,and geomorphology,and provides support for the improvement of theoretical frameworks in cold-region geomorphology,permafrost mechanics,and related disciplines.

Abstract:Integrating detailed seismic interpretation and analogue tectonic modeling experiments,this study investigates the unique structural characteristics and the dynamic formation and evolution mechanisms of the Bongor basin in the Central African shear zone.Geophysical interpretation indicates that the Bongor Basin exhibits characteristics of a typical inverted rift basin.The current structural configuration was controlled by two phases rifting during Early Cretaceous and the compression in Late Cretaceous-Paleogene,with the primary rift-related structures are still clearly identifiable.Multi-stage analogue tectonic modeling further confirm that the formation of the Bongor basin was controlled by two early phases of rifting and subsequent inversion,with the extension directions of the two rifting stages separated by 25°-45°.Combining these results and context of regional tectonic history,a geological model of the two-phase rifting in the Bongor basin was put forward.In the early Early Cretaceous,the opening of the South Atlantic Ocean triggered near north-south stretching between the South African and the Northeast African subplate.This led to the first phase of rifting in the Central African rift system basins,including the Bongor basin.During the late Early Cretaceous,both the shift of the main Atlantic expansion toward the equatorial region and the subduction of the Tethys Ocean toward the Eurasian continent caused a nearly northeast-southwest extensional stress between the Northeast African block and the South African block.Unlike other basins parallel to the Central African rift system,the northwest-trending Bongor basin underwent a second phase of rifting.The study presents new insights into the formation and evolution of the Bongor basin,which is of great significance for guiding future oil and gas exploration.

Abstract:Large-scale volcanic activity is recognized as one of the critical drivers of global climate and environmental changes,as well as biodiversity fluctuations.It can enhance marine surface primary productivity and promote the development of euxinic bottom water conditions,thus facilitating organic-rich sedimentation.Across the Ordovician-Silurian transition,intense global volcanic activities coincided with the widespread deposition of black shales and the development of organic-rich intervals characterized by extraordinarily high total organic matter(TOC≥3.0%).Based on more than 800 samples,including TOC,major and trace elements,mercury(Hg)concentrations and Hg isotopes,collected from over 20 typical wells and sections of the Wufeng-Lungmachi formations in South China,this study discusses the occurrence and identification features of visible volcanic ash layers and highlights the application of major and trace elements,Hg concentrations and isotopes to identify cryptotephra.Furthermore,the impact of volcanic activity on marine environmental changes and the formation of extraordinarily high organic matter deposits were investigated.The results suggest follows.(1)The distribution of visible volcanic ash and cryptotephra provides a robust basis for reconstructing volcanic history of this period.(2)Elevated phosphorus inputs from volcanic activity enhanced marine surface primary productivity and expanded the extent of anoxic bottom water.(3)The anoxic conditions promoted phosphorus recycling,thereby sustaining high primary productivity.(4)Enhanced volcanic weathering increased sulfate input,which could further promote euxinic conditions.Sustained volcanic activities and their associated climate and environmental effects contributed to the high primary productivity and euxinic conditions,ultimately leading to the extraordinarily high organic matter accumulation in the Wufeng-Lungmachi shale.

Abstract:This study demonstrates the efficacy of machine learning algorithms in classifying genetic types of Pb-Zn deposits through trace elements in sphalerite.It compiled a comprehensive trace element dataset comprising 3 117 sphalerite samples from 109 globally representative Pb-Zn deposits including MVT,VMS,SEDEX,skarn,and epithermal deposits.Twelve trace elements(Mn,Fe,Co,Cu,Ga,Ge,Ag,Cd,In,Sn,Sb,Pb)were systematically analyzed to develop a Tree-structured Parzen Estimator(TPE)-optimized Support Vector Machine(SVM)classification model.The model demonstrated exceptional discriminative performance on test datasets,achieving accuracy,recall,and F1-score values exceeding 0.97.SHAP(SHapley Additive exPlanations)interpretability analysis revealed Mn,Ge,and Co as critical discriminators among deposit types,providing quantitative insights into elemental controls on genetic classification.The discriminant index system of trace elements in sphalerite established in this paper not only provides a new technical means for the identification of ore genesis,but also provides innovative solutions for complex geological problems such as the analysis of composite metallogenic system and the prediction of concealed ore bodies.

Abstract:In order to investigate the heavy metal pollution level of soil and rice in the geological high background area dominated by volcanic weathering,taking the west of Jiangdong new district in Haikou as the research object,82 soil-rice matching samples were collected to measure the contents of As,Cd,Cu,Hg,Ni,Pb and Zn in soil and rice,and the geo-accumulation index method,Nemerow index method,matter-element extension model,the potential ecological risk assessment method were used to evaluate the pollution of farmland soil in the study area,using correlation analysis and PMF model to explore its main sources and contribution rate,and evaluate the health risk of rice consumption.The results show that there are severe Cu,Ni and Zn pollution in the study area,compared with the background value of soil in Hainan Province,the over standard multiples are 2.00,2.77 and 1.94 respectively,and compared with the risk screening value of agricultural land,the over standard rates are 23.17%,17.07%and 7.32%respectively.The land accumulation index method shows that As and Pb in farmland soil in the study area are in a pollution-free degree,and the pollution degree of other heavy metals is Ni>Cu>Zn>Cd>Hg,the pollution degree of Ni element is relatively large,and 7.31%of soil samples are of"medium strong pollution".The comprehensive pollution assessment results show that the pollution area is mainly concentrated in the south of volcanic rocks.Combined with PMF source analysis and spatial analysis results,Hg mainly comes from atmospheric sedimentation.The excessive contents of Cu,Ni and Zn are mainly caused by the weathering of volcanic rock soil forming parent material,Pb mainly comes from traffic pollution sources,and the contents of As and Cd are greatly affected by agricultural activities.There is a certain degree of health risk to human body by having rice,and As and Cd are the main contributing factors.The contents of As,Pb and Hg in rice are lower than the national food safety limits,and the over standard rate of Cd reaches 32.93%,there is a certain degree of health risk to human body by eating rice,As and Cd in rice seeds have a great impact on human health risk,with the contribution rates to non carcinogenic risk of 51.52%and 21.57%respectively,and the contribution rates to carcinogenic risk of 73.88%and 26.01%respectively.In conclusion,the farmland soil in the study area is polluted to a certain extent under the joint influence of volcanic rock weathering and human activities,the content of As in rice does not exceed the standard,but it is the largest potential risk element,it is necessary to focus on the health risks of As and Cd in rice produced in the study area,and formulate scientific and reasonable prevention and control strategies for farmland heavy metals.

Abstract:The Xiazhuang uranium ore field in North Guangdong is characterized by five sets of approximately equidistant NWW-trending diabase dikes,which are closely related to uranium mineralization.To determine the genesis of diabase and its relationship with uranium mineralization.This study systematically investigates the diagenetic age,genesis of diabase,and its controlling mechanisms on uranium mineralization through geochemical analysis of diabase,apatite U-Pb geochronology,and H-O isotopic analysis of ore-forming quartz,combined with regional tectonic background.Results indicate that:(1)The diabase was formed during two magmatic events(200-180 Ma and 150-140 Ma),corresponding to the Early Jurassic and Late Jurassic,respectively.(2)The diabase is enriched in large-ion lithophile elements(LILEs)and highly incompatible elements.The chondrite-normalized rare earth element(REE)patterns exhibit right-leaning trends and no significant Eu or Ce anomalies,indicating an intraplate basalt affinity derived from partial mantle melting with metasomatism by subduction-related fluids.(3)The early-stage diabase(200-180 Ma)served as favorable host rocks for uranium mineralization.The deep-seated faults associated with diabase emplacement provided pathways for ore-forming fluids,and the intersections between faults and diabase facilitated the formation of vein-type uranium deposits with crust-mantle hybrid fluids.The late-stage diabase(150-140 Ma)not only inherited the role of the early-stage diabase but also contributed mantle-derived fluids and mineralizing agents(ΣCO₂)during the 138-122 Ma uranium mineralization stage,promoting the formation of fractured alteration-type uranium deposits dominated by mantle-derived fluids.

Abstract:Marine-continental transitional(MCT)shale gas is an important successor of unconventional natural gas resources in China.Based on integrated analyses of literature review,outcrop investigation,exploration practice,drilling cores,and experimental testing,it systematically reviewed and compared the development history of shale gas globally and in China,examined the exploration progress and challenges of MCT shale gas in the Ordos basin,Sichuan basin,and adjacent areas,and conducted a comprehensive discussion of the key geological conditions for the formation of shale gas and its resource potential,challenges,and counter measures.The results show that MCT shale in China is mainly developed within the Carboniferous-Permian strata(Benxi,Shanxi,and Longtan formations),dominated by lagoon,swamp,and tidal flat facies,and possesses favorable conditions for shale gas formation and development potential.(1)The organic-rich shale intervals are thick and widespread,with dominant Type III organic matter,high organic matter abundance(average TOC content≥3.0%),and moderate thermal maturity(Ro=1.60%-2.61%),which are conducive to large-scale gaseous hydrocarbon generation.(2)Shale reservoirs are dominated by inorganic pores(clay mineral pores),with well-developed organic micropores(0.4-0.7 nm),and a high proportion of adsorbed gas(average 61.0%,up to 75%),providing favorable conditions for shale gas storage and enrichment.(3)The total MCT shale gas resource in China exceeds 50×10¹² m³,of which the favorable resource volume in the Jinci Member of the Benxi Formation,the Shan23 and Shan 22+1 sub-members of the Shanxi Formation in the Ordos basin reaches 16×10¹² m³.Notably,a commercial breakthrough has been achieved in the Shan23 sub-member,demonstrating promising exploration and development prospects.However,the exploration and development of MCT shale gas remain at the early breakthrough stage,facing many challenges such as strong heterogeneity of sweet spots and high clay mineral content,which constrain drilling,completion,fracturing,and development effectiveness.To achieve large-scale development of MCT shale gas requires integrated evaluation of"sedimentary facies-preservation conditions-resource potential,"as well as technological advances in"multi-cluster within stage+limited-entry fracturing"and"platform-based well pattern+3D well deployment."This will promote the coordinated co-production of shale gas,coal-rock gas,and tight gas within the MCT shale system in the context of the whole petroleum system.By overcoming bottlenecks in geological theory and engineering technology,MCT shale gas is expected to become a new strategic successor for increasing natural gas reserves and production in China.

Abstract:To clarify the deformation sequence and ore-controlling structures of the Longwangjiang Au-Sb ore-field in West Hunan,as well as to reveal the age and tectonic setting of its formation,it conducted detailed structural analyses and LA-ICP-MS U-Pb dating of ore-bearing quartz vein hydrothermal zircon.Additionally,it comprehensively analyzed regional tectonic evolution and age data.The study area underwent six stages of structural deformation events,progressing from early to late:Late Silurian NW-NWW compression,late Middle Triassic NW-NWW compression,late Late Triassic near SN compression,late Middle Jurassic NWW compression,Cretaceous regional NW-SE extension,and Mid-Late Cenozoic NEE-NE compression.The LA-ICP-MS U-Pb age of the quartz vein hydrothermal zircon was determined to be(211.8±4.8)Ma.The comprehensive analysis suggests that:mineralization primarily occurred during the Late Triassic(211-206 Ma)and the formation of the Longwangjiang ore-field is associated with late-stage hydrothermal activity triggered by the collision of the Indochina period with the South China margin during the intracontinental collision phase.The ore-field is situated within a block confined by the reverse thrust of the Longwangjiang fault(F1)and the Heitupo fault(F2).The F1 and F3 faults serve as ore-guiding structures,while the NE-NNE-trending strong foliated zones(shear zones)and the Jiangdongwan fault serve as ore-distributing and ore-bearing structures simultaneously.The ore-distributing and ore-bearing structures in the deep parts of the ore deposit have great mineral exploration potential;the Taojinping-Huomaotang area is a key region for exploration due to concentrated structural stress.

Abstract:Granitic pegmatite is extensively developed in the Yihuang area of Jiangxi Province,and tourmaline is commonly found within granitic pegmatite and its surrounding rocks(biotite monzogranite).Three distinct types of tourmalines have been identified in Tangyin area:randomly disseminated tourmaline(Tur-G)in biotite monzogranite,unzoned tourmaline(Tur-PU)and zoned tourmaline(Tur-PZ)in granitic pegmatite.However,the classification and origin of tourmaline,as well as its implications for the genesis of granitic pegmatite,remain unclear.This study analyzed the major,trace elements,and boron isotopic compositions using EPMA and LA-(MC)-ICP-MS.From Tur-G type→Tur-PU type→Tur-PZ tourmalines core to rim,the concentrations of Al and Fe initially increase and subsequently decrease,whereas the concentrations of Mg,Na,Ca,Ti,Sc,V,Cr,Co,Ni,Sr,Ga,and rare earth elements exhibit an opposite trend,decreasing first and then increasing.The δ11B values for Tur-G,Tur-PU,Tur-PZ type tourmalines core and rim are-10.77‰--8.87‰,-10.59‰--8.73‰,-11.07‰--10.09‰,and-11.05‰--8.95‰,respectively.It is believed that all tourmalines belong to the iron-magnesium tourmaline series within the alkaline tourmaline group and are of magmatic origin.Specifically,Tur-G,Tur-PU,and Tur-PZ tourmalines crystallized during the late granite melt,the early granitic pegmatite melt,and the late magma-hydrothermal stages,respectively.The changes in the Fe3+/Fe2+ratio and V content of the tourmaline revealed that the oxygen fugacity of the magma melt exhibit a trend of initially decreasing and subsequently increasing.The concentrations of Mg,Na,Ca,Ti,Sc,V,Cr,Co,Ni,Sr,and Ga in the tourmaline reflect variations in elemental composition within the melt.The tourmaline found in both the Tangyin granitic pegmatite and biotite monzogranite exhibits a concentrated and comparable boron isotope composition,ranging from-11.07‰ to-8.73‰.This similarity suggests that both rock types originated from the same magma source,with the initial magma being derived from the partial melting of the continental crust,specifically calcium-poor and aluminum-rich metamorphic mudstone and sandstone.

Abstract:Recent years have witnessed increasing attention on the enrichment of selenium(Se)and tellurium(Te)within the Pulang super-large porphyry Cu-Au-Mo deposit;however,their resource potential and comprehensive utilization value remain unclear.In this paper it presents a systematical investigation of the principal host minerals and spatial distribution patterns of Se and Te within the deposit,employing methods such as LA-ICP-MS and ME-MS61r,and evaluation of their resource prospects.The findings reveal that Se is primarily enriched in chalcopyrite and molybdenite,while the main host mineral for Te is molybdenite.At the spatial distribution level,the contents of Se and Te in sulfides of the main mining area are obviously higher than those in the eastern mining area on the plane,which may be related to differences in mineralization types and ore-forming temperatures.However,in a single exploration line section,the contents of Se and Te show no obvious regular changes with depth.Regarding utilization value,the analysis of Cu and Mo concentrates shows that the Se content in Cu concentrates is 170×10‒6-200×10‒6,and that in Mo concentrates reaches 250×10‒6,both meeting the recovery indexes for associated Se minerals.The Te content in Cu concentrates is 3.6×10‒6-5.5×10‒6,and that in Mo concentrates is 16.4×10‒6.Only Mo concentrates slightly exceed the recovery standard for associated Te minerals,and due to the Cu-dominated mining characteristics of the deposit,the comprehensive recovery value of Te is relatively limited.In terms of resource estimation,based on the proven Cu resource of 5.11 Mt,the potential Se resource of the Pulang deposit is calculated to be approximately 4 440 t,reaching the super-large scale.

Abstract:Prospecting for ore bodies in the deep and peripheral zones remains pivotal for breakthroughs in the volcanic-hosted massive sulfide(VHMS)-type Cu-polymetallic ore field of the Baiyinchang district.However,conventional geophysical methods have limitations in application due to shallow electromagnetic interference and insufficient resolution at depth.To address these challenges,this study innovatively integrates the Wide-Field Electromagnetic Method(WFEM)and Coded Source Electromagnetic Sounding(CSES)for deep exploration in the Xiaotieshan mining area.The results demonstrate that the resistivity of ferromanganese siliceous rocks and lead-zinc ores is below 100 Ω·m,while the ore-hosting Quartz-keratophyre tuffs exhibit a low resistivity(mean value:191 Ω·m).In contrast,the subquartz-keratophyre,as the main ore-controlling geological unit,shows significantly higher resistivity(mean value:1 976 Ω·m),revealing quantifiable electrical contrasts.Subvolcanic intrusions are characterized by dendritic high-resistivity anomalies(>1 500 Ω·m),with favorable prospecting targets identified in transitional zones(<400 Ω·m),deep extensions of known ore bodies,and low-resistivity anomalies atop high-resistivity zones.The combined application of two geophysical methods in complex stratigraphic regions of volcanic rocks demonstrates synergistic effects:the wide-field electromagnetic method effectively reveals the electrical structure of volcanic basement and deep-seated high-resistivity rock masses,while the encoded-source electromagnetic sounding method enables high-precision delineation of middle-shallow low-resistivity mineralized zones.Based on integrating geophysical anomalies and metallogenic dynamics,a composite genetic model-termed"volcanic structure-hydrothermal convection-tectonic activation"-is proposed to elucidate the multi-stage mineralization processes.A geological-geophysical"magma-tectonic-alteration synergistic prospecting model"is established,delineating four prospective targets.These findings provide critical constraints for drill hole verification and offer scientific guidance for deep-peripheral exploration in the Baiyinchang ore field and regional analog studies.

Abstract:The Longsang deposit is a porphyry copper-molybdenum mining area where mineral exploration is currently underway in the eastern section of the Gangdese metallogenic belt.To further constrain the magmatic-mineralization age and evaluate the metallogenic potential of the ore-bearing intrusions,detailed field geological surveys,and drill core logging were conducted,and zircon U-Pb dating and trace element analysis were performed on the mineralized rock bodies of biotite granodiorite and biotite monzogranite porphyry,with Re-Os dating of molybdenite veins in this study.The results indicate that the ore-bearing intrusions in the Longsang deposit are of crystallization ages of(21.80±0.29)Ma and(21.68±0.23)Ma,while the molybdenite mineralization age is(19.1±0.6)Ma.Additionally,zircon trace elements exhibit high Ce/Nd,(Ce/Nd)/Y,and low Dy/Yb ratios,along with negative Eu anomalies and positive Ce anomalies,indicating that the magma had high oxygen fugacity and water content,which facilitated the enrichment and transport of ore-forming elements such as Cu and Mo.In conclusion,the Longsang deposit underwent diagenetic mineralization during the Miocene epoch,demonstrating significant mineralization potential.These findings provide valuable insights into the spatiotemporal distribution patterns of deposits in the eastern Gangdese belt,contributing to a deeper understanding of regional metallogeny.

Abstract:Plankton form the foundation of marine ecosystems,and changes in their community structure and phenology affect ecosystem function and biogeographical patterns.Global warming drives sea surface temperature increases,resulting in poleward shifts of plankton distribution,with the leading edge advancing more noticeably while the core and trailing edge remain relatively stable.Warming also causes phenological shifts in some species,such as earlier spring events and delayed autumn events.The extent of distribution and phenological changes varies among plankton groups,mainly affecting community structure at the margins,while no significant changes have been observed in the dominant species of community cores.If future ocean circulation patterns remain stable,the risk of major shifts in plankton community cores from the tropics to subarctic regions is low,and dominant species in polar communities are also unlikely to change substantially in the next century.Long-term systematic observation in Chinese seas is still insufficient,and key regions lack critical data.Synthesizing evidence from polar and coastal regions,this study predicts that if warming does not exceed 2℃,the positions of community cores in China's coastal plankton communities may shift,but the risk of substantial structural change remains low.

Abstract:Since the Cenozoic,a large amount of high-potassium calc-alkaline volcanic rocks(basaltic trachyandesite and trachyandesite)have developed in the Tengchong area,but the specific formation process remains unclear.Based on petrographic analysis,in this paper it conducts whole-rock major element and mineral major and trace element analyses of these volcanic rocks,and discusses their formation and evolution process in combination with the published data.The rocks commonly exhibit porphyritic textures,with phenocrysts predominantly consisting of olivine,pyroxene,and plagioclase,and the development of glomerocrysts.Clinopyroxene phenocrysts commonly show normal zoning,reverse zoning,and oscillatory zoning,with oscillatory zoning indicating multi-stage mafic magma replenishment and possible local contamination during magma evolution.Whole-rock major element analysis reveals that these rocks belong to the high-potassium calc-alkaline rock series.Clinopyroxene,orthopyroxene,and plagioclase phenocrysts and glomerocrysts show similar REE and trace element distribution patterns,with clinopyroxene being the most enriched in trace elements,followed by plagioclase,and orthopyroxene showing the lowest concentrations.The geochemical characteristics of olivine phenocrysts suggest that the magma source region may have originated from partial melting of peridotite,while the trace element compositions of the whole rocks and clinopyroxene phenocrysts record geochemical signatures characteristic of an arc-related tectonic setting.The mineral equilibrium temperature-pressure calculations reveal the existence of two intermediate to felsic magma reservoirs beneath the study area:a shallow dacitic magma reservoir(depth 8.3-13.6 km)and a deep andesitic magma reservoir(depth 18.4-30.2 km).The studied samples are derived from the deeper reservoir.Their formation involves mafic magma recharge,triggering mixing between crystal mush and melt;when newly generated melts become dominant within the reservoir,eruption is triggered,carrying semi-consolidated magmatic clots to the surface and forming the typical(glomerocrystic)textures.

Abstract:With the advance of green energy transformation in the 21st century,the demand for copper has surged dramatically and porphyry copper deposits as the main suppliers of global copper resources have been paid great attention from both academic and industrial communities.Although a set of classic models have been established for Cenozoic porphyry copper deposits,the porphyry copper deposits located at Paleozoic Central Asian Orogenic Belt exhibit unique characteristics and their genesis mechanisms are not fully understood.Taking important porphyry copper deposits in Xinjiang as research objects,this study reveals that these deposits generally experienced multiple magmatic activities with time spanning up to 100-200 Ma and often underwent superimposed and/or modification mineralization stages after porphyry mineralization.For example,the Tuwu-Yandong deposit has mineral assemblages of anhydrite,chalcopyrite,calcite,and chlorite after porphyry mineralization;the Yuhai-Sanchakou mining area exhibits post-porphyry veins of epidote,quartz,chlorite,zeolite,and calcite;and the Halasu copper belt shows late alteration and mineralization with copper-bearing sulfide veins and argillic alteration.Fluid inclusion studies further confirm that new fluid systems would overprint on the hydrothermal fluid system in the porphyry stage.Based on these observations,it proposes a new superimposed mineralization model of modification for Paleozoic porphyry copper deposits in Xinjiang.In the early stage of island arc evolution,pre-mineralization magmatic activities may form unmineralized alterations in the mining areas such as early sodic-calcic alteration and epidote alteration at the Halasu belt.With the maturity of the island arc,tectonic triggers such as flat subduction facilitated high oxygen fugacity,water-rich magmatic activities which partly have adakite-like geochemical features and formed the porphyry-type mineralization and alteration in the mining areas such as diorite porphyry in Tuwu-Yandong and diorite porphyry and granodiorite porphyry at Halasu.Further tectonic evolution including change of subduction polarity or postcollisional asthenospheric upwelling led to new magmatic hydrothermal activities superimposed on preexisting porphyry-type mineralization and alteration.Moreover,post-mineralization tectonic metamorphism may also introduce new mineralizing materials or cause remobilization of preexisting ores.The aforementioned models underscore the importance of specific tectonic or magmatic activities that may superimpose on pre-existing porphyry mineralization systems in long-lived arcs with sustained multistage magmatic activities.These activities,beyond the classic types of porphyry mineralization alteration,require special attention due to their exploration potential to introduce new mineralizing components.