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Structural characteristics and tectonic division of the Zambezi Delta basin in the offshore East Africa:evidences from gravity and seismic data

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Acta Oceanologica Sinica 2024年第4期43卷 105-118页

作者： Guozhang Fan Wen Li Liangbo Ding Wanyin Wang Hongping Wang Dingding Wang Lin Li Hao Wang Chaofeng Wang Qingluan Wang Ying Zhang Hangzhou Research Institute of Petroleum Geology PetroChinaHangzhou 310023China College of geological Engineering and geomatics Chang’an universityXi’an 710054China Key Laboratory of Marine Geology and Environment Chinese Academy of SciencesQingdao 266071China National Engineering Research Center of Offshore Oil and Gas Exploration Beijing 100028China department of Earth Environment and Resources SciencesUniversity of Naples FedericoⅡNaples 80138Italy

The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration *** to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic *** on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)***,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity *** thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole ***,uplifts and depressions are divided based on a sedimentary layer thickness of 3 *** research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west *** nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and ***“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira *** pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.

关键词： Zambezi Delta basin satellite altimetry gravity anomaly Beira High fault division uplift and depression pattern

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Retraction to: Shear strength of extremely altered serpentinites based on degree of saturation (Ankara, Turkey)

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Journal of Mountain Science 2024年第4期21卷 1446-1446页

作者： Koray ULAMIŞ department of geological Engineering Ankara UniversityAnkara 06830Turkey

The Editor in Chief has retracted this *** publication,concerns were raised over potentially inconsistent data-for example,the author mentioned residual soil with silt fraction,but Fig.5 shows even the smallest grains are beyond silt *** analysis showed that Fig.6 and Fig.9 show both loose and dense soils exhibiting very similar dilatance behaviour,which is not *** author shared raw data,but it was incomplete and could not be *** Editor in Chief,therefore,has lost confidence in the findings of this *** author does not agree to this retraction.

关键词： Shear saturation smallest

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Biomechanical behavior of grass roots at different gauge lengths

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Journal of Mountain Science 2024年第9期21卷 3201-3214页

作者： FU Jiangtao ZHOU Zhe GUO Hong ZHAO Jimei YU Dongmei WU Jie HU Xiasong School of Civil Engineering and Architecture Shaanxi University of TechnologyHanzhong 723000China Crop Science postdoctoral research station Qinghai UniversityXining 810016China School of geological Engineering Qinghai UniversityXining 810016China Qinghai institute of Salt Lakes Chinese Academy of SciencesXining 810008China department of Geographical Science Shaanxi University of TechnologyHanzhong 723000China

Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s ***,the extent to which and how these biomechanical properties of herbaceous roots are influenced remain *** better understand the behavior of roots in tension under different conditions and to illustrate these behaviors,uniaxial tensile tests were conducted on the Poa araratica roots as the gauge length increased from 20 mm to 80 ***,ANOVA was used to test the impact of the significant influences of gauge length on the biomechanical properties,nonlinear regression was applied to establish the variation in the biomechanical properties with gauge length to answer the question of the extent to which the biomechanical properties are influenced,and Weibull models were subsequently introduced to illustrate how the biomechanical properties are influenced by gauge *** results reveal that(1)the variation in biomechanical properties with root diameter depends on both the gauge length and the properties themselves;(2)the gauge length significantly impacts most of the biomechanical properties;(3)the tensile resistance,tensile strength,and tensile strain at cracks decrease as the gauge length increases,with values decreasing by 20%-300%,while Young’s modulus exhibits the opposite trend,with a corresponding increase of 30%;and(4)the Weibull distribution is suitable for describing the probability distribution of these biomechanical properties;the Weibull modulus for both tensile resistance and tensile strain at cracks linearly decrease with gauge length,whereas those for tensile strength and Young’s modulus exhibit the opposite *** tensile resistance,tensile strength,and tensile strain at the cracks linearly decrease with increasing gauge length,while the tensile strength and Young’s modulus linearly increase with increasing gauge length.

关键词： Biomechanical properties of roots Weibull distribution ANOVA Uniaxial tensile test Linear regression

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Revisiting the Mg isotopic systematics of siliciclastic components of sediments and sedimentary rocks:A new geochemical proxy of continental weathering in Earth's history

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Science China Earth Sciences 2024年第2期67卷 620-633页

作者： Tianzheng HUANG Bing SHEN Kangjun HUANG Meng NING Chao LI Jinzhuang XUE Yuanlin SUN Baoqi HUANG Key Laboratory of Orogenic Belt and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijing100871China State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life and EnvironmentsDepartment of GeologyNorthwest UniversityXi’an710069China Institute of Sedimentary Geology Chengdu University of TechnologyChengdu610059China Key Laboratory of Rhenium-Osmium Isotopic Geochemistry Chinese Academy of Geological SciencesBeijing100037China

The Mg isotopic compositions of siliciclastic components(δ^(26)Mg_(sili))of sediments and sedimentary rocks have been commonly used to constrain the intensity of continental weathering,based on observations of,(1)an upward enrichment of26Mg in modern weathering profiles,(2)preferential uptake of26Mg in soil clays,and(3)general positive correlations between weathering intensities andδ^(26)Mg_(sili)***,not all weathering profiles display an upward increase ofδ^(26)Mg_(sili),and not all soil clays enrich in26Mg,complicating the interpretations ofδ^(26)Mg_(sili)data of sediments and sedimentary *** further explore the controls ofδ^(26)Mg_(sili)of sediments and sedimentary rocks,here we measuredδ^(26)Mg_(sili),mineralogical compositions and major element compositions of deep sea sediments from South China Sea(SCS)and carbonate rock samples from two late Paleozoic sections in South *** samples show decreasing trends of both normalized Mg concentration(Mgnorm)andδ^(26)Mg_(sili)values with the increase of weathering intensity,while SCS sediments samples do not show any correlation between Mgnormorδ^(26)Mg_(sili)values and weathering intensity.A three-stages weathering model is developed to explain the observed Mgnorm andδ^(26)Mg_(sili)*** the new model,weathering can be divided into three stages,(1)the preliminary weathering stage characterized by dissolution of primary minerals and formation of secondary clay minerals in saprolite,(2)the transitional stage with massive vermiculite and chlorite formation on the bottom of soil,and(3)the advanced stage showing dissolution of vermiculite and chlorite in the top of *** new model explains anδ^(26)Mg_(sili)increase and Mgnormdecrease with an increase weathering intensity in preliminary weathering stage and decrease of Mgnormandδ^(26)Mg_(sili)with increase weathering intensity in advanced weathering *** revised weathering model warrants the application of Mg isotope in the study of contin

关键词： Clay mineral Chemical weathering CIA Soil Weathering model

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Assessing the Performance of a Dynamical Downscaling Simulation Driven by a Bias-Corrected CMIP6 Dataset for Asian Climate

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Advances in Atmospheric Sciences 2024年第5期41卷 974-988页

作者： Zhongfeng XU Ying HAN Meng-Zhuo ZHANG Chi-Yung TAM Zong-Liang YANG Ahmed M.EL KENAWY Congbin FU Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China School of Atmospheric Sciences Nanjing UniversityNanjing 210093China Earth System Science Programme The Chinese University of Hong KongHong KongChina department of geological Sciences Jackson School of GeosciencesThe University of Texas at AustinAustinTexasUSA Instituto Pirenaico de Ecología Consejo Superior de Investigaciones Científicas(CSIC)Campus de Aula Dei1005Zaragoza 50059Spain department of Geography Mansoura UniversityMansoura 35516Egypt

In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific *** simulations were conducted with a 25-km grid spacing for the period 1980–*** first simulation(WRF_ERA5)was driven by the European Centre for Medium-Range Weather Forecasts Reanalysis 5(ERA5)dataset and served as the validation *** original GCM dataset(MPI-ESM1-2-HR model)was used to drive the second simulation(WRF_GCM),while the third simulation(WRF_GCMbc)was driven by the bias-corrected GCM *** bias-corrected GCM data has an ERA5-based mean and interannual variance and long-term trends derived from the ensemble mean of 18 CMIP6 *** demonstrate that the WRF_GCMbc significantly reduced the root-mean-square errors(RMSEs)of the climatological mean of downscaled variables,including temperature,precipitation,snow,wind,relative humidity,and planetary boundary layer height by 50%–90%compared to the WRF_***,the RMSEs of interannual-tointerdecadal variances of downscaled variables were reduced by 30%–60%.Furthermore,the WRF_GCMbc better captured the annual cycle of the monsoon circulation and intraseasonal and day-to-day *** leading empirical orthogonal function(EOF)shows a monopole precipitation mode in the WRF_*** contrast,the WRF_GCMbc successfully reproduced the observed tri-pole mode of summer precipitation over eastern *** improvement could be attributed to a better-simulated location of the western North Pacific subtropical high in the WRF_GCMbc after GCM bias correction.

关键词： bias correction multi-model ensemble mean dynamical downscaling interannual variability day-to-day variability validation

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Characterization of alpine meadow surface crack and its correlation with root-soil properties

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Journal of Arid Land 2024年第6期16卷 834-851页

作者： WU Yuechen ZHU Haili ZHANG Yu ZHANG Hailong LIU Guosong LIU Yabin LI Guorong HU Xiasong School of geological Engineering Qinghai UniversityXining 810016China Key Laboratory of the Cenozoic Resources and Environment on the North Rim of the Qinghai-Tibet Plateau Xining 810016China Qinghai Provincial Transportation Planning and Design Research Institute Co.Ltd. Xining 810002China

Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack *** characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development *** far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively ***,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth ***,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation *** results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine *** the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"*** crack length,width,depth,and length density were identified as the crack char

关键词： alpine meadow grassland degradation grassland cracks crack characterization index crack morphology root length density grey relation analysis

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Lithium Isotope Analytical Methods and Implications for Rare-Metal Mineralization in Granite-Pegmatite Systems: An Overview

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Journal of Earth Science 2024年

作者： Xiang-Ying Ye Bin Li Dong-Bo Tan Ke-Cheng Liu Zhi-Yong Zhu Hafiz Muhammad Siddique Yi-Lin Xiao Key Laboratory of Metallogenic Prediction of Nonferrous Metals and geological Environment Monitoring (Ministry of Education)， School of Geosciences and Info-physics， Central South University CAS Key Laboratory of Geospace Environment and department of Plasma Physics and Fusion Engineering， University of Science and Technology of China Institute of Geology， Chinese Academy of geological Sciences CAS Key Laboratory of Crust-Mantle Materials and Environments， School of Earth and Space Sciences， University of Science and Technology of China Chinese Academy of Sciences Center of Excellence in Comparative Planetology

The origin of highly-fractionated granite-pegmatite systems and their associated rare metal mineralization has been widely studied， but there is still ongoing debate. Prevailing hypotheses suggest that pegmatite formation and the associated rare metal mineralization are closely related to aqueous fluid processes. Lithium (Li) isotope analysis has been widely applied to trace granite-pegmatite evolution. This is because lithium is widely present in various minerals (e.g.， mica， tourmaline) that record the melt and fluid compositions， and lithium isotopes are sensitive to magmatic-hydrothermal processes. We briefly review the methodology of Li isotope analyses， the mechanisms of Li isotopic fractionation， and， in particular， Li isotope fractionation in granite-pegmatite system based on Li isotope data we have collected and the latest developments in Li isotope geochemistry. With the development of analytical technology， high-precision measurement of the Li content and isotopic compositions have facilitated a series of scientific breakthroughs in understanding the magmatic-hydrothermal evolution of rare-element ore deposits. Li isotope analysis on bulk mineral separates show ability to trace various hydrothermal processes (e.g. exotic or exsolved fluids). In situ Li isotope analysis methods has been enhanced by the development of new， homogeneous mineral reference materials. In situ SIMS and LA-MC-ICP-MS Li isotope measurements on minerals (e.g.， tourmaline) will likely become more important in studying the fluid–rock interactions in magmatic， metamorphic， and hydrothermal processes， as well as on pegmatite petrogenesis and rare-metal mineralization.

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Spatial distribution characteristics and influence factor analysis of landslides——case study of the Hanwang area in Qinba Mountains

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Earthquake Research Advances 2024年第3期4卷 55-65页

作者： Jikai Zhang Yanbo Cao Wen Fan Wenbo Zheng Zequan Wang Chengcheng He Hongquan Teng School of geological Engineering and geomatics Chang’an UniversityXi'an710054China Mine geological Disasters Mechanism and Prevention Key Laboratory Xi'an710054China China DK Comprehensive Investigate and Design Research Institute Co. Ltd.Xi'an710054China Shaanxi Engineering Technology Research Center for Urban Geology and Underground Space Xi'an710068China Shaanxi Hydrogeology Engineering Geology and Environment Geology Survey CenterXi'an710068China Chang'an University Xi'anShaanxiChina

The geological hazards of landslides in Hanwang Town, Ziyang County, Ankang City, Shaanxi Province, have emerged. Yet, the current understanding of the spatial distribution characteristics and influencing factors of landslides in this area remains unclear. Combining the results of remote sensing interpretation and field investigation, seven influencing factors, namely, elevation, slope direction, slope gradient, distance from rivers, distance from faults, engineering geologic lithology, and distance from roads, are selected for the study. The distribution characteristics of landslides in each influencing factor and the influence of the resolution of the Digital Elevation Model(DEM) on the results are statistically and analytically analyzed. Furthermore, two highrisk landslides within the study area were subjected to comprehensive analysis, integrating the findings from drilling and other field investigations in order to examine their deformation mechanisms. Based on this analysis,the following conclusions were derived:(1) 34 landslides in the study area, mainly small earth landslides, with a distribution density of 0.42/km~2, threatening 414 people and property of about 55.87 million Yuan.(2)The landslides in the study area easily occur in the <400 m elevation range;the landslides are developed in all slope directions, the gradient is mainly concentrated in the range of 10°–40°, the distribution density of the landslides is higher in the closer distance from the river and the faults(0–200 m), the landslide-prone strata are mainly the softer and weaker metamorphic rocks, and the landslides are mainly around roads.(3) The resolution of the DEM should be selected based on the specific conditions of the study area, the requirements of the investigation, and the scale of the landslide. Opting for an appropriate DEM resolution is advantageous for understanding the patterns of landslides and conducting risk assessments in the region.(4) The Zhengjiabian landslide is a trac

关键词： Landslide Spatial distribution Influence factor Landslide density Deformation mechanism DEM

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Cooling History of Mesozoic Magmatism and Implications for Large-Scale Gold Mineralization in the Jiaodong Peninsula, East China: Constraints from T-t Paths Determined by U-Pb Thermochronology of Zircon and Apatite

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Journal of Earth Science 2024年第3期35卷 878-889页

作者： Guangyan Zhou Mingchun Song Long Li Yan Luo DGraham Pearson Jianbo Zhou Zhengjiang Ding Xuefeng Yu Yingxin Song Jie Li Shiyong Li Faculty of Earth Sciences China University of GeosciencesWuhan 430074China department of Earth&Atmospheric Sciences University of AlbertaEdmontonAlberta T6G 2E3Canada Hebei Key Laboratory of Strategic Critical Mineral Resources Hebei GEO UniversityShijiazhuang 050031China Shandong Provincial No.6 Exploration Institute of Geology and Mineral Resources Weihai 264209China College of Earth Sciences Jilin UniversityChangchun 130061China Ministry of Natural Resources Key Laboratory of Gold Mineralization Processes and Resources Utilization Key Laboratory of Metallogenic-Geologic Processes and Comprehensive Utilization of Minerals Resources in Shandong ProvinceShandong Institute of Geological SciencesJinan 250013China Shandong Nuclear Industry geological Group 273 Yantai 264006China

The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold *** the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization,which are strongly influenced by the cooling/uplift histories of the hosting *** performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong *** zircon and apatite U-Pb ages are 156.9±1.2 and 137.2±2.4 Ma for the Linglong intrusion,129.9±1.0 and 125.0±3.8 Ma for the Qujia intrusion,119.5±0.7 and 117.2±1.8 Ma for the Liulinzhuang intrusion,118.6±1.0 and 111.6±1.6 Ma for the Nansu intrusion,*** coupled zircon and apatite data of these granitoids indicate a slow cooling rate(11.9°C/Ma)in the Late Jurassic,and rapid uplift and cooling(35.8-29.2°C/Ma)in the Early *** dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong *** implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.

关键词： magmatism geochronology zircon apatite gold deposits Jiaodong Peninsula

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Optical monitoring of particle aggregates

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Journal of Environmental Sciences 2009年第1期21卷 2-7页

作者： John Gregory department of Civil Environmental and Geomatic EngineeringUniversity College London

Methods for monitoring particle aggregation are briefly reviewed. Most of the techniques are based on some form of light scattering and may be greatly dependent on the optical properties of aggregates, which are not generally known. As fractal aggregates grow larger their density can become very low and this has important practical consequences for light scattering. For instance, the scattering coefficient may be much less than for solid objects, which means that the aggregates can appear much smaller than their actual size by a light transmission method. Also, for low-density objects, a high proportion of the scattered light energy is within a small angle of the incident beam, which may also be relevant for measurements with aggregates. Using the ＂turbidity fluctuation＂ technique as an example, it is shown how the apparent size of hydroxide flocs depends mainly on the included impurity particles, rather than the hydroxide precipitate itself. Results using clay suspensions with hydrolyzing coagulants and polymeric floceulants under different string conditions are discussed.

关键词： monitoring method flocculation turbidity fluctuation

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