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Elemental Compositions of Clinopyroxenes from Southern Okinawa Trough Basalt:Implications for Magmatism and Structural Environment in an Initial Back-Arc Basin

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Journal of Ocean University of China 2024年第3期23卷 643-653页

作者： GUO Kun ZHAI Shikui FAN Di ZHANG Xia ZHANG Yu ZHU Zhimin Laoshan laboratory Qingdao 266237China key laboratory of submarine geosciences and prospecting techniques Ministry of EducationCollege of Marine GeosciencesOcean University of ChinaQingdao 266100China key laboratory of submarine geosciences&Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China

The major and trace elemental compositions of clinopyroxene from basalt were used to characterize the nature of the primitive magma and structural environment beneath the southern Okinawa Trough(SOT),which is an initial back-arc basin at a continental *** clinopyroxenes in the basalt were augite with variable Mg^(#)contents(73.37-78.22).The regular variations in major oxide contents(i.e.,CaO,FeO,TiO_(2),and Cr)with decreasing Mg#implied that the clinopyroxenes evolved from being enriched in Mg,Ca,and Cr to being enriched in Fe and *** clinopyroxenes had relatively low rare earth element concentrations(7.51×10^(-6) to 12.68×10^(-6))and negative Eu anomalies(δEu=0.67-0.95).The Kd_(cpx) values of clinopyroxenes(0.2-0.26),which were used to examine whether the clinopyroxene was equilibrated with its host basalt,demonstrate that these clinopyroxene phenocrysts were not captured crystals but were instead produced by crystallization differentiation of the *** calculated clinopyroxene crystallization temperatures showed a narrow range of 990-1061℃,and their crystallization pressures ranged from 2.0 to 3.2 *** geochemistry features of these clinopyroxenes indicated that the parent magma belonged to the subalkaline tholeiitic magma series and suggested that the magma experienced crystallization differentiation of olivine,plagioclase,and clinopyroxene,where the crystallization of plagioclase occurred earlier than that of *** with geophysical data,this research on primitive magma and its crystallization differentiation from clinopyroxene indicates that the SOT is in the stage of‘seafloor spreading’and that basaltic rocks produced from tholeiitic magma represent the generation of oceanic crust.

关键词： trace elements clinopyroxenes southern Okinawa Trough seafloor spreading back-arc basin

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Auto-Detection Method Using Convolution Neural Network for Bottom-Simulating Reflectors

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Journal of Ocean University of China 2024年第3期23卷 683-694页

作者： XU Haowei XING Junhui YANG Boxue LIU Chuang key laboratory of submarine geosciences and prospecting techniques MOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

In studies on gas hydrate,bottom-simulating reflectors(BSR)are used to determine the potential hydrate-bearing sedimentary ***,BSR detection is performed manually by experienced ***,a method for implementing an auto-matic BSR detection process should be *** this study,we develop a novel architecture for BSR characterization using the convolutional neural network(CNN)*** propose the use of Stokes’transform(ST)to obtain a time-frequency spectrum for the input of *** fully uses the frequency content of the seismic data,and a part of the 3D seismic data collected from the Blake Ridge is utilized to train the *** seismic records with variable signal-to-noise ratios(SNR),as well as Blake Ridge seismic data,were used to validate the detection effect of the *** show that the CNN trained by this method exhibits excellent performance in noise-resistant testing and achieves an accuracy of more than 89% in field seismic data detection.

关键词： BSR CNN Stocks’transform gas hydrate Blake Ridge

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Inversion of Seabed Geotechnical Properties in the Arctic Chukchi Deep Sea Basin Based on Time Domain Adaptive Search Matching Algorithm

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Journal of Ocean University of China 2024年第4期23卷 933-942页

作者： AN Long XU Chong XING Junhui GONG Wei JIANG Xiaodian XU Haowei LIU Chuang YANG Boxue Jiangsu Automation Research Institute Lianyungang 222061China key laboratory of submarine geosciences and prospecting techniques MOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266071China

The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic *** this paper,the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of *** time-domain adaptive search matching algorithm was used and validated on our established theoretical *** misfit between the inversion result and the theoretical model is less than 0.067%.The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the *** average acoustic impedance of sub-seafloor strata is 2.5026×10^(6) kg(s m^(2))^(-1)and the average grain size(θvalue)of the seafloor surface sediment is 7.1498,indicating the predominant occurrence of very fine silt sediment in the study *** of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.

关键词： time domain adaptive search matching algorithm acoustic impedance inversion sedimentary grain size Arctic Ocean Chukchi Deep Sea Basin

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Geochronology and Geochemistry of the Xingxingxia Triassic A-type Granites in Central Tianshan,NW China:Petrogenesis and Tectonic Implications

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 337-351页

作者： HUANG Zengbao LI Xiyao ZHAO Hao LU Qing Geological Survey of Gansu Province Lanzhou 735000China key laboratory of submarine geosciences and prospecting techniques MOE and College of Marine GeosciencesOcean University of ChinaQingdaoShandong 266100China Research Institute of Petroleum Exploration and Development Shengli OilfieldSINOPECDongyingShandong 257000China

The Triassic granitoids in Central Tianshan play a key role in determining the petrogenesis and tectonic evolution on the southern margin of the Central Asian orogenic *** this study,we present SHRIMP zircon U-Pb ages,Hf isotopic and geochemical data on the Xingxingxia biotite granite,amazonite granite and granitic pegmatite in Central Tianshan,NW *** U-Pb dating yielded formation ages of 242 Ma for the biotite granite and 240 Ma for the amazonite *** granitoid rocks have high K_(2)O with low MgO and CaO *** are enriched in Nb,Ta,Hf and Y,while being depleted in Ba and Sr,showing flat HREE patterns and negative Eu *** have typical A-type granite geochemical signatures with high Ga/A_(1)(8–13)and TFeO/(TFeO+MgO)ratios,showing an A_(2) affinity for biotite granite and an A_(1) affinity for amazonite granite and granitic *** ε_(Hf)(t)values of the granitoids are 0.45–2.66,with Hf model ages of 0.99–1.17 *** suggests that these A-type granites originated from partial melting of the lower *** propose that Xingxingxia Triassic A-type granites formed under lithospheric extension from post-orogenic to anorogenic intraplate settings and NE-trending regional strike-slip fault-controlled magma emplacement in the upper crust.

关键词： Triassic A-type granite Xingxingxia Central Tianshan Central Asian orogenic belt

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Acoustic Velocity-Based Inversion of the Physical Properties of Sea Ice in the Central Arctic Region

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Journal of Ocean University of China 2024年第5期23卷 1213-1220页

作者： KONG Yadong XING Junhui XU Haowei XU Chong key laboratory of submarine geosciences and prospecting techniques Ministry of Education (MOE) and College of Marine Geosciences Ocean University of China laboratory for Marine Mineral Resources Qingdao Marine Science and Technology Center

Studying the Arctic sea ice contributes to a comprehensive understanding of the climate system in polar regions and offers valuable insights into the interplay between polar climate change and the global climate and environment. One of the key research aspects is the investigation of the temperature, salinity, and density parameters of sea ice to obtain essential insights. During the 11th Chinese National Arctic Research Expedition, acoustic velocity was measured on an ice core at a short-term ice station, however, temperature, salinity, and density were not measured. In the present work, we utilized a genetic algorithm to invert these obtained acoustic velocity data to sea ice temperature, salinity, and density parameters on the basis of the relationship between acoustic velocity and the physical properties of Arctic summer sea ice. We validated the effectiveness of this inversion procedure by comparing its findings with those of other researchers. The results indicate that within the normalized depth range of 0.43 – 0.94, the ranges for temperature, salinity, and density are-0.48 –-0.29℃, 1.63 – 3.35, and 793.1 – 904.1 kg m-3, respectively.

关键词： acoustic velocity Arctic sea ice genetic algorithm inversion of sea ice properties

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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 China Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine Geosciences Ocean University of China Guangzhou Marine Geological Survey China Geological Survey Shandong Earthquake Agency State key laboratory for Tunnel Engineering China University of Mining and Technology (Beijing)

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

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First-Arrival Picking Method for Active Source Data with Ocean Bottom Seismometers Based on Spatial Waveform Variation Characteristics

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Journal of Ocean University of China 2024年第4期23卷 970-980页

作者： LIU Hongwei XING Lei ZHU Henghua ZHANG Jin ZHANG Jing LIU Huaishan key laboratory of submarine geosciences and prospecting techniques Ministry of EducationCollege of Marine GeosciencesOcean University of ChinaQingdao 266100China laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266071China College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China Shandong Institute of Geological Survey Jinan 250014China

The precision and reliability of first-arrival picking are crucial for determining the accuracy of geological structure inversion using active source ocean bottom seismometer(OBS)refraction *** methods for first-arrival picking based on sample points are characterized by theoretical errors,especially in low-sampling-frequency OBS data because the travel time of seismic waves is not an integer multiple of the sampling *** this paper,a first-arrival picking method that utilizes the spatial waveform variation characteristics of active source OBS data is ***,the distribution law of theoretical error is examined;adjacent traces exhibit variation characteristics in their ***,a label cross-correlation superposition method for extracting highfrequency signals is presented to enhance the first-arrival picking *** from synthetic and field data verify that the proposed approach is robust,successfully overcomes the limitations of low sampling frequency,and achieves precise outcomes that are comparable with those of high-sampling-frequency data.

关键词： first-arrival picking spatial waveform variation label cross-correlation superposition method

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Dynamic Location Method for Shallow Ocean Bottom Nodes Using the Levenberg-Marquart Algorithm

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Journal of Ocean University of China 2024年第4期23卷 953-960页

作者： TONG Siyou LI Junjie XU Xiugang FANG Yunfen WANG Zhongcheng key laboratory of submarine geosciences and prospecting techniques MOEOcean University of ChinaQingdao 266100China laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266237China R&D Center of BGP CNPCZhuozhou 072751China Insitute of Shengli Oilfield SINOPECDongying 257022China

Ocean bottom node(OBN)data acquisition is the main development direction of marine seismic exploration;it is widely promoted,especially in shallow sea ***,the OBN receivers may move several times because they are easily affected by tides,currents,and other factors in the shallow sea environment during long-term *** uncorrected,then the imaging quality of subsequent processing will be *** conventional secondary positioning does not consider the case of multiple movements of the receivers,and the accuracy of secondary positioning is *** first arrival wave of OBN seismic data in shallow ocean mainly comprises refracted *** this study,a nonlinear model is established in accordance with the propagation mechanism of a refracted wave and its relationship with the time interval curve to realize the accurate location of multiple receiver *** addition,the Levenberg-Marquart algorithm is used to reduce the influence of the first arrival pickup error and to automatically detect the receiver movements,identifying the accurate dynamic relocation of the *** simulation and field data show that the proposed method can realize the dynamic location of multiple receiver movements,thereby improving the accuracy of seismic imaging and achieving high practical value.

关键词： OBN dynamic location method Levenberg-Marquart algorithm seismic exploration of shallow sea

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Early Devonian Post-collisional Granitic Magmatism in the North Qilian Orogenic Belt,Western China:Insights into Lithospheric Delamination and Orogenic Collapse

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 352-367页

作者： WANG Qian ZHAO Xilin MENG Yuanku YU Shengyao LIU Yanan College of Earth Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China Nanjing Center China Geological SurveyNanjing 210016China key laboratory of submarine geosciences and prospecting techniques MOEInstitute for Advanced Ocean StudyCollege of Marine GeosciencesOcean University of ChinaQingdaoShandong 266100China Sinopec Qingdao Liquefied Natural Gas Co. Ltd.QingdaoShandong 266400China

Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic *** Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive *** Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,*** of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type *** from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic ***,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat *** together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional *** data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian *** tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for

关键词： post-collisional magmatism lithospheric delamination extensional collapse North Qilian Orogenic Belt

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Storm Liquefaction Deposits:A Possibility of Time Reversal in Sedimentary Strata of an Estuarial Coastal Area

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Journal of Ocean University of China 2024年第4期23卷 961-969页

作者： XU Guohui REN Yupeng HU Guanghai LIU Zhiqin SUN Yongfu LIN Lin key laboratory of Marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China Shandong Provincial key laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China key laboratory of submarine geosciences and prospecting techniques Ministry of EducationOcean University of ChinaQingdao 266100China First Institute of Oceanography Ministry of Natural ResourceQingdao 266061China National Deep Sea Center Qingdao 266237China

In the sedimentary strata dating of estuarial coastal areas,it is often found that there is phenomenon of time-reversal in *** seabed sediments could be liquefied under storm waves.A laboratory wave flume experiment demonstrated that storm-induced liquefaction deposits are formed by the oscillations of liquefied *** this paper,the particle size distribution and ^(210)Pb_(ex) specific activity of the sediment samples from the liquefaction disturbed zone and adjacent stable zone of the Yellow River Delta were *** stratigraphic divisions based on storm liquefaction deposit sequence can effectively explain the vertical changes in particle size and ^(210)Pb_(ex) specific *** to the differentiation of particles during the storm induced liquefaction,coarse and fine particles regrouped,which could explain the phenomenon of time-reversal in dating data.

关键词： ^(210)Pb_(ex)specific activity liquefaction deposition reversal sediment

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