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The composition of magmatic-hydrothermal fluids and their related metal mineralization

Science China Earth Sciences 2025年第1期68卷 208-225页

作者： Qihai SHU Jun DENG State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences and Resources China University of Geosciences Frontiers Science Center for Deep-time Digital Earth China University of Geosciences

Magmatic hydrothermal deposits are important sources of many bulk, precious, and rare metals, and have attracted interest from both academic and industrial communities. However, it is still unclear if the major enrichment of the ore-forming metals occurs in the parental magma source region, during the magma evolution, or after the fluid exsolution. Fluid inclusions trapped in hydrothermal minerals crystallized in the early, high-temperature stage before metal precipitation record information close to that of the initially exsolved magmatic fluids, which are helpful in revealing whether the metals have been already significantly enriched prior to the hydrothermal stage. In this study, available compositional data of such early-stage fluid inclusions from magmatic hydrothermal systems globally have been compiled. The results indicate that the concentrations of Cu,Sn, and W respectively from the Cu-, Sn-, and W-mineralized fluids are significantly higher than the hydrothermal systems that do not produce ores with the corresponding metals. This suggests that Cu, Sn, and W could have already been enriched in the magma source and/or magma evolution stage. The Mo concentrations show no difference between Mo-mineralized and Mobarren fluid systems, indicating no significant pre-enrichment in the source region or during the magma evolution. This also implies that an efficient collection of Mo from a large volume of magmas is required to account for the formation of a large Mo deposit. Almost all the hydrothermal fluids contain high concentrations of Fe and Zn-Pb, but only a few of them eventually form Fe or Zn-Pb deposits, reflecting an important role of the hydrothermal evolution process on the selective metal *** above results indicate that different metals are enriched in different stages of a magmatic hydrothermal system, and that the major roles played in the formation of a deposit vary with the metal types. In addition to the metal concentrations in the o

关键词： Magmatic hydrothermal deposits Fluid inclusions LA-ICP-MS Metal enrichment Mineralization mechanism

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A Hybrid Approach for Pavement Crack Detection Using Mask R-CNN and Vision Transformer Model

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Computers, Materials & Continua 2025年第1期82卷 561-577页

作者： Shorouq Alshawabkeh Li Wu Daojun Dong Yao Cheng Liping Li Faculty of Engineering China University of GeosciencesWuhan430074China

Detecting pavement cracks is critical for road safety and infrastructure *** methods,relying on manual inspection and basic image processing,are time-consuming and prone to *** deep-learning(DL)methods automate crack detection,but many still struggle with variable crack patterns and environmental *** study aims to address these limitations by introducing the Masker Transformer,a novel hybrid deep learning model that integrates the precise localization capabilities of Mask Region-based Convolutional Neural Network(Mask R-CNN)with the global contextual awareness of Vision Transformer(ViT).The research focuses on leveraging the strengths of both architectures to enhance segmentation accuracy and adaptability across different pavement *** evaluated the performance of theMaskerTransformer against other state-of-theartmodels such asU-Net,TransformerU-Net(TransUNet),U-NetTransformer(UNETr),SwinU-NetTransformer(Swin-UNETr),You Only Look Once version 8(YoloV8),and Mask R-CNN using two benchmark datasets:Crack500 and *** findings reveal that the MaskerTransformer significantly outperforms the existing models,achieving the highest Dice SimilarityCoefficient(DSC),precision,recall,and F1-Score across both ***,the model attained a DSC of 80.04%on Crack500 and 91.37%on DeepCrack,demonstrating superior segmentation accuracy and *** high precision and recall rates further substantiate its effectiveness in real-world applications,suggesting that the Masker Transformer can serve as a robust tool for automated pavement crack detection,potentially replacing more traditional methods.

关键词： Pavement crack segmentation transportation deep learning vision transformer Mask R-CNN image segmentation

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Halogen composition and heterogeneity in the continental lithospheric mantle

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Science China Earth Sciences 2025年第1期68卷 310-314页

作者： Chunfei CHEN State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences

1. Introduction Halogens, including fluorine(F), chlorine(Cl), bromine(Br), and iodine(I), are highly mobile and water-soluble elements that can become significantly enriched in melts and fluids. In fluids and melts, halogens react with nearly all metals and readily form complexes with metal cations, significantly influencing the distribution of metal elements between different phases. Therefore, halogens play a crucial role in the migration, enrichment, and mineralization of key metals in the lithosphere(Weis et al., 2012; Liu et al., 2024).

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Orbit determination and thrust force modeling for a maneuvered GEO satellite using two-way adaptive Kalman filtering

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Science China(Physics,Mechanics & Astronomy) 2012年第4期55卷 738-743页

作者： XU TianHe HE KaiFei XU GuoChang Xi'an research Institute of Surveying and Mapping Xi'an 710054China gfz german research centre for geosciences Potsdam 14473Germany

A two-way adaptive Kalman filter is proposed by combining a two-way filter with an adaptive filter for orbit determination of a maneuvered GEO satellite.A method of using Newton's high-resolution differential formula and polynomial fitting for modeling the thrust force of a maneuvered GEO satellite is *** adaptive factor,which balances the contributions of the measurements and the dynamic model information,is determined by using a two-segment function and predicted residual *** with a maneuvered GEO satellite tracked by the Chinese ground tracking network were conducted to verify the performance of the proposed orbit determination technique and the method of thrust force *** results show that refining the thrust force model is beneficial for the orbit determination of a maneuvered GEO satellite;the two-way adaptive Kalman filter can efficiently control the influence of the dynamic model errors on the orbit state estimate.

关键词： geostationary satellite Kalman filter adaptive Kalman filter orbit determination thrust force

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Precise orbit determination for LEO satellites:single-receiver ambiguity resolution using GREAT products

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Geo-Spatial Information Science 2022年第1期25卷 63-73页

作者： Xingxing Li Yujie Qin Keke Zhang Jiaqi Wu Wei Zhang Qian Zhang Hongmin Zhang School of Geodesy and Geomatics Wuhan UniversityWuhanHubeiChina Department of Geodesy and Remote Sensing of the german research centre for geosciences(gfz) PotsdamGermany

In recent years,the large Low Earth Orbit(LEO)constellations have become a hot topic due to their great potential to improve the Global Navigation Satellite Systems(GNSS)positioning *** of the important focus is how to obtain the accurate and reliable orbits for these constellations with dozens of LEO *** GNSS-based Precise Orbit Determination(POD)will be exclusively performed to achieve this goal,where the Integer Ambiguity Resolution(IAR)plays a key role in acquiring high-quality *** this study,we present a comprehensive analysis of the benefit of the single-receiver IAR in LEO POD and discuss its implication for the future LEO *** perform ambiguity-fixed LEO POD for four typical missions,including Gravity Recovery and Climate Experiment(GRACE)Follow-On(GRACE-FO),Swarm,Jason-3 and Sentinel-3,using the Uncalibrated Phase Delay(UPD)products generated by our GREAT(GNSS+research,Application and Teaching)*** results show that the ambiguity fixing processing can significantly improve the accuracy of LEO *** are negligible differences between our UPD-based ambiguity-fixed orbits and those based on the Observable Signal Bias(OSB)and Integer Recovery Clock(IRC)products,indicating the good-quality of UPD products we *** to the float solution,the fixed solution presents a better consistency with the external precise science orbits and the largest accuracy improvement of 5 mm is achieved for GRACE-FO ***,the benefit can be observed in laser ranging residuals as well,with a Standard Deviation(STD)reduction of 3–4 mm on average for the fixed *** from the absolute orbits,the relative accuracy of the space baseline is also improved by 20–30%in the fixed *** result demonstrates the superior performance of the ambiguity-fixed LEO POD,which appears as a particularly promising technique for POD of future LEO constellations.

关键词： Precise orbit determination single-receiver ambiguity resolution onboard GPS observation LEO

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Mutual impact of true triaxial stress, borehole orientation and bedding inclination on laboratory hydraulic fracturing of Lushan shale

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3131-3147页

作者： Yongfa Zhang Anfa Long Yu Zhao Arno Zang Chaolin Wang College of Civil Engineering Guizhou UniversityGuiyang550025China Helmholtz centre Potsdam GFZ German Research Centre for GeosciencesPotsdam14473Germany

Unconventional resources like shale gas has been the focus of intense research and development for two decades. Apart from intrinsic geologic factors that control the gas shale productivity (e.g. organic matter content, bedding planes, natural fractures, porosity and stress regime among others), external factors like wellbore orientation and stimulation design play a role. In this study, we present a series of true triaxial hydraulic fracturing experiments conducted on Lushan shale to investigate the interplay of internal factors (bedding, natural fractures and in situ stress) and external factors (wellbore orientation) on the growth process of fracture networks in cubic specimens of 200 mm in length. We observe relatively low breakdown pressure and fracture propagation pressure as the wellbore orientation and/or the maximum in situ stress is subparallel to the shale bedding plane. The wellbore orientation has a more prominent effect on the breakdown pressure, but its effect is tapered with increasing angle of bedding inclination. The shale breakdown is followed by an abrupt response in sample displacement, which reflects the stimulated fracture volume. Based on fluid tracer analysis, the morphology of hydraulic fractures (HF) is divided into four categories. Among the categories, activation of bedding planes (bedding failure, BF) and natural fractures (NF) significantly increase bifurcation and fractured areas. Under the same stress regime, a horizontal wellbore is more favorable to enhance the complexity of hydraulic fracture networks. This is attributed to the relatively large surface area in contact with the bedding plane for the horizontal borehole compared to the case with a vertical wellbore. These findings provide important references for hydraulic fracturing design in shale reservoirs.

关键词： True triaxial hydraulic fracturing experiment In situ stress state Bedding planes Natural fractures Wellbore orientation Shale reservoirs

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AQDS Enhances Degradation of BDE-47 by Promoting Shewanella oneidensis MR-1-mediated Fenton Reaction with Fe(III)-containing Minerals

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Journal of Earth Science 2025年

作者： Yongguang Jiang Siqi Zhu Zhou Jiang Yiran Dong Liang Shi School of Environmental Studies， China University of geosciences State Key Laboratory of Biogeology and Environmental Geology， China University of geosciences Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science， China University of geosciences State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution， Ministry of Ecology and Environment， China University of geosciences(Wuhan)

Electron shuttles are widespread in the environments and play important role in microbe-mineral interaction. This study investigated the effects of a model electron shuttle (i.e.， anthraquinone-2， 6-disulfonate， AQDS) on Shewanella oneidensis MR-1-mediated Fenton reaction and subsequent degradation of 2， 2′， 4， 4′-tetrabrominated diphenyl ether (BDE-47). Three Fe(III)-containing minerals， namely， ferrihydrite， goethite and nontronite， were used as electron acceptors and Fe(II) sources. With each mineral， additions of 0.01 – 1 mM AQDS in the reactions significantly enhanced Fe(III) reduction by S. oneidensis MR-1 and increased the amounts of Fe(II) produced in anoxic phase. As a result， the amounts of cumulative ·OH formed in oxic phase were increased by 10% – 287%. Regression analysis revealed that ·OH cumulation has significant linear correlation with sorbed Fe(II) but not aqueous and structural Fe(II). This finding may be ascribed to the higher reactivity of sorbed Fe(II) in oxygenation than the latter two types of Fe(II). With more ·OH， the degradation efficiency of BDE-47 was elevated by 31% – 173%. Collectively， AQDS enhances ·OH formation and BDE-47 degradation by promoting production of Fe(II)， particularly sorbed Fe(II) in S. oneidensis MR-1-mediated Fenton reaction with Fe(III)-containing minerals.

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Addressing administrative units in international tsunami early warning systems: shortcomings in international geocode standards

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International Journal of Digital Earth 2012年第4期5卷 356-371页

作者： Matthias Lendholt Martin Hammitzsch german research centre for geosciences Centre for GeoInformation TechnologyPotsdamGermany

Administrative units reflect the territorial hierarchies established within all countries of the *** units are addressable with geocodes that provide a bijective mapping between territories and unique identification *** warning systems for natural or man-made hazards often map affected or threatened areas to administrative units to establish a spatial reference that is comprehensible to all parts of the *** these territories in an international context has several requirements,such as worldwide coverage,completeness and topicality,which must be met by geocode *** this paper,the practicability and suitability of international geocode standards are examined in the context of the requirements of large-scale early warning *** paper exposes the insufficiencies and limitations of existing geocode standards International Organization for Standardization(ISO)-3166,Second Administrative Level Boundaries data set project(SALB)and Nomenclature of the Territorial Units for Statistics(NUTS)and emphasises the suitability of the non-official hierarchical administrative subdivision codes(HASC).The analysis is framed in the context of addressing affected areas for an Indian Ocean tsunami early warning *** system was developed within the Distant Early Warning Systems project according to the requirements of the United Nations Educational,Scientific and Cultural Organization(UNESCO)Intergovernmental Oceanic Commission for Regional Tsunami Watch Providers(RTWPs).

关键词： digital earth early warning system spatial reference geocode SALB HASC ISO-3166

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Effects of external temperature and dead volume on laboratory measurements of pore pressure and injected volume in a rock fracture

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1461-1469页

作者： Yinlin Ji Christian Kluge Hannes Hofmann Guido Blöcher Helmholtz centre Potsdam GFZ German Research Centre for GeosciencesPotsdam14473Germany State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou221116China

The accurate evaluation of pore pressure and injected volume is crucial for the laboratory characterization of hydromechanical responses of rock fractures. This study reports a series of laboratory experiments to systematically demonstrate the effects of external temperature and dead volume on laboratory measurements of pore pressure and injected volume in a rock fracture. We characterize the hydraulic aperture of the fracture as a function of effective normal stress using the exponential aperture *** model is then employed to predict the pore pressure change and injected volume in the fracture without the influences of external temperature and dead volume. The external temperature changes in the cyclic loading test due to the Joule-Thompson effect for fluids. The effect of external temperature on pore pressure change in the fracture can be well explained by thermal pressurization of fluids. Our results also show that the external dead volume can significantly lower the pore pressure change in the fracture during the cyclic loading test under undrained conditions. The injected volume can also be substantially enlarged due to the external dead volume in a typical pore pressure system. Internal measurement of the pore pressure in the fracture using a fiber optic sensor cannot exclude the influences of external temperature and dead volume, primarily because of the good hydraulic communication between the fracture and pore pressure system. This study suggests that the effects of external temperature and dead volume on pore pressure response and injected volume should be evaluated for accurate laboratory characterization and inter-laboratory comparison.

关键词： Fracture aperture Thermal pressurization External dead volume Pressure attenuation Injected volume Fiber optic sensor

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Revisiting the dissolution of biogenic Si in marine sediments： a key term in the ocean Si budget

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Acta Geochimica 2017年第3期36卷 429-432页

作者： Patrick Frings Department of Geoscience Swedish Museum of Natural History 10405 Stockholm Sweden Earth Surface Geochemistry GFZ German Research Centre for Geosciences 14473 Telegrafenberg Potsdam Germany

Of the　~240*10^(12)mol year^(-1)of biogenic silica(bSi)produced by diatoms and other silicifying organisms,only roughly 3%–4%escapes dissolution to be permanently *** the global scale,how,where and why b Si is preserved in sediment is not well *** help address this,I compile 6245 porewater dissolved Si concentrations from 453 sediment cores,to derive the concentration gradient at the sediment–water interface and thus diffusive fluxes out of the *** range from\0.002 to 3.4 mol m^(-2)year^(-1),and are independent of temperature,depth and *** classified by sediment lithology,predominantly siliceous sediments unsurprisingly have higher mean diffusive fluxes than predominantly calcareous or clay-rich *** with the areal extent of these lithologies,the‘best-guess’global sedimentary b Si recycling flux is69 9 10^(12)mol year^(-1).

关键词： Biogenic silica Diatoms Ocean Si cycle Dissolution

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