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Regional trends and petrologic factors inhibit global interpretations of zircon trace element compositions

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Geoscience Frontiers 2024年第5期15卷 300-307页

作者： Nick M.W.Roberts Christopher J.Spencer Stephen Puetz C.Brenhin Keller Simon Tapster Geochronology and Tracers Facility British Geological SurveyNottingham NG125GGUK Department of geological Sciences and geological Engineering Queen’s UniversityKingstonOntarioCanada Atkinson Dr Suite 704HonoluluHI 96814USA Department of Earth Sciences Dartmouth CollegeHanoverNew HamphireUSA

The trace element composition of zircon reveals information about the melt that they are derived from,as such,detrital zircon trace element compositions can be used to interrogate melt compositions,and thus the evolution of the continental crust in time and ***,we present a global database of detrital zircon compositions and use it to test whether average global trends for five common petrogenetic proxies truly represent secular changes in continental *** demonstrate that the secular trend is broadly comparable across continental regions for Ti-in-zircon temperatures,but for other trace element ratios interrogated,secular trends are highly variable between continental *** trace element ratios result from multiple petrologic variables,we argue that these petrogenetic proxies can be overinterpreted if projected to global geologic *** particular,we caution against the interpretation of crustal thickness from trace elements in zircon,and we argue that our results negate current hypotheses concerning secular changes in crustal thickness.

关键词： Detrital zircon Trace elements Secular change Eu anomaly Crustal thickness

Characterizing occurrence of emerging organic contaminants in Dinaric karst catchment of Jadro andZrnovnica springs,Croatia

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Emerging Contaminants 2024年第3期10卷 158-169页

作者： Ana Selak Jasmina Lukac Reberski Ivana Boljat Josip Terzic HGI-CGS-Croatian geological survey Department of Hydrogeology and Engineering GeologySachsova 210000ZagrebCroatia

The occurrence of emerging organic contaminants(EOCs)was investigated in vulnerable Dinaric karst catchment of Jadro andZrnovnica springs in Croatia,under varying flow conditions and across three different water resource types(groundwater,springs,and surface water).The maximal EOCs concentration in both springs were observed following autumn recharge events,while during peak discharge no detection above the limits of detection(LOD)was recorded due to dilution *** to springs,groundwater from deep borehole exhibited highest total EOCs concentration under low flow conditions,underscoring the considerable karst aquifer vulnerability and its oligotrophic *** peak EOCs concentration in karstic Cetina River coincided with the river's lowest *** highest mass flux of 1013 g/day was determined for very mobile pharmaceutical metformin detected in *** presence of potentially persistent to very persistent compounds,like DEET and 1H-benzotriazole,which exhibited highest detection frequencies across all sampling sites,was observed in association with varying hydrological *** regarding the occurrence of identified EOCs include surface contamination infiltrating directly through ponors and highly karstified areas,potential persistence in the epikarst and aquifer matrix,and site-specific contamination sources for compounds such as 1H-benzotriazole,gabapentin,and ketoprofen found in *** evaluate the risk of inadvertent human exposure to EOCs across various age groups,we utilized measured spring concentrations and calculated drinking water equivalent levels(DWEL),which ranged from 1.4 mg/L for cotinine to 503 mg/L for sucralose,both detected in Jadro *** EOCs concentrations in ng/L are unlikely to pose a significant risk to healthy population,long-term exposure to EOCs mixture remains *** scarcity of research on EOCs in karst environments on both global and national levels,our study enhances comp

关键词： Karst groundwater Emerging organic contaminants Pharmaceuticals Human exposure DEET 1H-benzotriazole

Microseismic observations reveal that internal waves intensify seabed methane release

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Science China Earth Sciences 2024年第10期67卷 3186-3203页

作者： Zhaoyang TIAN Yonggang JIA Junjiang ZHU Tian CHEN Hui WANG Chunsheng JI Chengyu LIU Longyu LU Manchao HE Shandong Provincial Key Laboratory of Marine Environment and geological Engineering Ocean University of ChinaQingdao 266100China Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Guangzhou Marine geological survey China Geological SurveyGuangzhou 511458China Shandong Earthquake Agency Jinan 250014China State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Internal waves transport material and energy from the upper water column to the deep ocean, disturbing seabed sediments and resulting in phenomena such as seabed erosion and changes in topography. On the northern slope of the South China Sea and in many coastal margins worldwide, the zones with internal wave action closely overlap with areas where natural gas hydrates are present. However, due to significant differences in the spatial and temporal scales, understanding the influence of internal waves on methane releases from deep seabeds is challenging. In this study, in situ observations of seabed microseismicity and internal waves are conducted at water depths of 655 meters and 1450 meters in the Pearl River Canyon of the South China Sea. The microseismicity caused by internal waves and seabed methane releases is identified, and a method to establish the correlation between internal waves and seabed methane releases through the use of microseismic recordings is proposed, aiming to obtain direct observational evidence of internal waves intensifying seabed methane releases. The results show that internal waves and seabed methane releases generate significant microseismic signals, indicating the continuous influence of internal waves on the deep seabed of the northern slope of the South China Sea and revealing active methane release phenomena on the seabed. At both long and short time scales, internal waves increase the frequency of seabed methane releases by 4.2 times and 2.4 times, respectively, while also enhancing the intensity of these releases. These changes are influenced by the alterations in seabed flow velocity, pressure, and temperature that are induced by internal wave activities. This study emphasizes that microseismic signals are effective carriers of information for multiscale geological processes on seabeds and suggests that internal waves exacerbate marine geological hazards and contribute to global climate change by intensifying seabed methane relea

关键词： Internal waves Seabed methane release Microseismic observation Ocean bottom seismometer Northern slope of the South China Sea

Comparative study of different machine learning models in landslide susceptibility assessment: A case study of Conghua District, Guangzhou, China

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China Geology 2024年第1期7卷 104-115页

作者： Ao Zhang Xin-wen Zhao Xing-yuezi Zhao Xiao-zhan Zheng Min Zeng Xuan Huang Pan Wu Tuo Jiang Shi-chang Wang Jun He Yi-yong Li Wuhan Center China Geological SurveyMinistry of Natural Resources(Geosciences Innovation Center of Central South China)Wuhan 430205China Guangzhou Institute of geological survey Guangzhou 510080China Hubei Transportation Planning Design Institute Co. LtdWuhan 430050China

Machine learning is currently one of the research hotspots in the field of landslide *** clarify and evaluate the differences in characteristics and prediction effects of different machine learning models,Conghua District,which is the most prone to landslide disasters in Guangzhou,was selected for landslide susceptibility *** evaluation factors were selected by using correlation analysis and variance expansion factor *** four machine learning methods namely Logistic Regression(LR),Random Forest(RF),Support Vector Machines(SVM),and Extreme Gradient Boosting(XGB),landslide models were *** analysis and evaluation of the model were conducted through statistical indices and receiver operating characteristic(ROC)*** results showed that LR,RF,SVM,and XGB models have good predictive performance for landslide susceptibility,with the area under curve(AUC)values of 0.752,0.965,0.996,and 0.998,*** model had the highest predictive ability,followed by RF model,SVM model,and LR *** frequency ratio(FR)accuracy of LR,RF,SVM,and XGB models was 0.775,0.842,0.759,and 0.822,*** and XGB models were superior to LR and SVM models,indicating that the integrated algorithm has better predictive ability than a single classification algorithm in regional landslide classification problems.

关键词： Landslides susceptibility assessment Machine learning Logistic Regression Random Forest Support Vector Machines XGBoost Assessment model geological disaster investigation and prevention engineering

Responses of Nutrients to the Precipitation Variation and Land Use in Subtropical Monsoonal Small Mountainous Rivers:A Case Study of Baixi Watershed

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Journal of Ocean University of China 2024年第2期23卷 383-391页

作者： TIAN Yuan GAO Fei CAO Ke LV Shenghua DUAN Xiaoyong YIN Ping Qingdao Institute of Marine Geology China Geological SurveyMinistry of Natural ResourcesQingdao 266237China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China

Small mountainous rivers are characterized by large instantaneous fluxes and susceptible to extreme weather events,which can rapidly transport materials into the sea and have a significant impact on the ecological environment of estuaries and *** order to investigate the seasonal characteristics of nutrients in small mountainous rivers in the subtropical monsoon region and the output pattern to the sea during heavy precipitation,surveys on the mountainous rivers were carried out in Baixi watershed in August 2020(wet season),March 2021(dry season)and June 2021(Meiyu period).The results showed that the dissolved inorganic nitrogen(DIN)of the rivers has an average concentration of 752μg L^(−1)in the wet season and 1472μg L^(−1)in the dry *** concentrations of dissolved inorganic phosphorus(DIP)in wet season and dry season were 63μg L^(−1)and 51μg L^(−1),*** by the changes of land use in sub-watersheds,DIN concentrations in the mainstream increased from 701μg L^(−1)in the upper reaches to 1284μg L^(−1)in the middle *** rainstorms during the Meiyu period in the watershed caused the pulse runoff in the *** maximum daily runoff reached 70 times that before *** maximum daily fluxes of DIN and DIP were 109 and 247 times that before rains,*** view that the watershed experienced several rainstorms in the wet season,the river,with pulse runoff,carries a large amount of nutrients into the sea in a short time,which will have a significant impact on the environment of Sanmen bay and its adjacent sea.

关键词： small mountainous river uneven precipitation rainstorm pulse runoff nitrogen and phosphorus

Climate and Soil Geochemistry Influence the Soil Organic Carbon Content in Drylands of the Songliao Plain, Northeast China

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1394-1403页

作者： LIU Kai DAI Huimin SONG Yunhong LIANG Shuai YANG Zhongfang School of Earth Sciences and Resources China University of Geosciences Key Laboratory of Black Soil Evolution and Ecological Effect Ministry of Natural Resources/Liaoning Province Shenyang Center of China geological survey Northeast Geological S&T Innovation Center of China Geological Survey

The understanding of the spatial distribution of soil organic carbon(SOC) and its influencing factors is crucial for comprehending the global carbon cycle. However, the impact of soil geochemical and climatic conditions on SOC remains limited, particularly in dryland farming areas. In this study, we aimed to enhance the understanding of the factors influencing the distribution of SOC in the drylands of the Songliao Plain, Northeast China. A dataset comprising 35,188 measured soil samples was used to map the SOC distribution in the region. Multiple linear regression(MLR) and random forest models(RFM) were employed to assess the importance of driving indicators for SOC. We also carried out partial correlation and path analyses to further investigate the relationship between climate and geochemistry. The SOC content in dryland soils of the Songliao Plain ranged from 0.05% to 11.63%, with a mean value of 1.47% ± 0.90%. There was a notable increasing trend in SOC content from the southwest to the northeast regions. The results of MLR and RFM revealed that temperature was the most critical factor, demonstrating a significant negative correlation with SOC content. Additionally, iron oxide was the most important soil geochemical indicator affecting SOC variability. Our research further suggested that climate may exert an indirect influence on SOC concentrations through its effect on geochemical properties of soil. These insights highlight the importance of considering both the direct and indirect impact of climate in predicting the SOC under future climate change.

关键词： climate change Northeast China soil geochemistry soil organic carbon

Hcable for Time-Lapse Seismic Monitoring of Marine Carbon Capture and Storage

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哈尔滨工程大学学报（英文版） 2024年第3期23卷 628-633页

作者： Bin Liu Yutong Fu Pengfei Wen Guangzhou Marine geological survey Guangzhou 511458China Sanya Institute of South China Sea Geology Guangzhou Marine Geological SurveyChina Geological SurveySanya 572025China

To ensure project safety and secure public support, an integrated and comprehensive monitoring program is needed within a carbon capture and storage(CCS) project. Monitoring can be done using many well-established techniques from various fields, and the seismic method proves to be the crucial one. This method is widely used to determine the CO_(2) distribution, image the plume development, and quantitatively estimate the concentration. Because both the CO_(2) distribution and the potential migration pathway can be spatially small scale, high resolution for seismic imaging is demanded. However, obtaining a high-resolution image of a subsurface structure in marine settings is difficult. Herein, we introduce the novel Hcable(Harrow-like cable system) technique, which may be applied to offshore CCS monitoring. This technique uses a highfrequency source(the dominant frequency>100 Hz) to generate seismic waves and a combination of a long cable and several short streamers to receive seismic waves. Ultrahigh-frequency seismic images are achieved through the processing of Hcable seismic data. Hcable is then applied in a case study to demonstrate its detailed characterization for small-scale structures. This work reveals that Hcable is a promising tool for timelapse seismic monitoring of oceanic CCS.

关键词： Carbon capture and storage Hcable Seismic monitoring High resolution image High frequency seismic source

Application of geophysical methods in fine detection of urban concealed karst:A case study of Wuhan City,China

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China Geology 2024年第3期7卷 517-532页

作者： Dao-han Liu Lei Wang Lei Liu Jun-jie Xu Jian-qiang Wu Pan Liu Wuhan Center China Geological SurveyWuhan430205China Central South China Center for Geoscience Innovation Wuhan430205China Geophysical Exploration Brigade of Hubei geological Bureau Wuhan 430056China

The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering ***,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks in the urban area of 8569.15 km^(2),predominantly consists of concealed karst areas where occasional ground collapse events occur,posing significant threats to underground engineering *** address these challenges,a comprehensive geological survey was conducted in Wuhan,focusing on major karstrelated *** methods offer advantages over drilling in detecting concealed karst areas due to their efficiency,non-destructiveness,and *** paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst,selected eight effective geophysical methods for field experimentation,evaluated their suitability,and proposed method combinations for different karst *** results show that different geophysical methods have varying applicability for karst detection in Wuhan,and combining multiple methods enhances detection *** specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.

关键词： Ground Penetrating Radar(GPR) Electric Resistivity Tomography(ERT) Opposing-coils Transient Electromagnetic Method(OCTEM) Microtremor Array Measurements(MAM) Multi-channel Analysis of surface wave(MASW) Multi-source surface wave exploration(MSSW) Electromagnetic wave CT(EM CT) Surface Nuclear Magnetic Resonance(SNMR) Concealed karst Urban geological survey engineering

Paleoenvironmental Evolution and Organic Matter Enrichment Genesis of the Late Turonian Black Shale in the Southern Songliao Basin, NE China

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1338-1358页

作者： BAI Jing XU Xingyou LIU Weibin ZHAO Wenzhi JIANG Hang State Key Laboratory of Continental Shale Oil Key Laboratory of Unconventional Oil and Gas China Geological Survey Oil and Gas survey China Geological Survey Research Institute of Petroleum Exploration Development of PetroChina Strategic Research Center of Oil and Gas Resources Ministry of Natural Resources

The Upper Cretaceous Qingshankou Formation black shales, deposited in the late Turonian(LTB shales), are the main source rocks of the Songliao Basin. The origins of organic matter enrichment of the shales is a contentious subject fuelling many ongoing debates. This study investigates the genesis of the organic matter-rich shale by using molecular geochemistry. The LTB shales can be divided into three sections. The Section Ⅰ shales were deposited in saline, stratified and anoxic water conditions, which are related to seawater incursion events. At least three episodic and periodic seawater incursion events were recognized during Section Ⅰ shale deposition. The Section Ⅱ shales deposited in brackish to fresh and deep lake-level conditions with high primary productivity, which are related to lake-level transgression. The Section Ⅲ shales were deposited under fresh and slightly oxidized water conditions, which are related to lake-level regression. Two organic matter enrichment models for the LTB shales are identified, that is, the seawater incursion model and the maximum lake-level transgression sedimentation model, which act on different shale sections, both playing significant roles in the enrichment of organic matter.

关键词： Cretaceous enrichment genetics late Turonian organic matter-rich shale paleoenvironmental evolution Songliao Basin