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Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea

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Acta Oceanologica Sinica 2015年第5期34卷 75-80页

作者： MENG Xiangmei LI Guanbao HAN Guozhong KAN Guangming First Institute of Oceanography State Oceanic Administration Key Laboratory of Marine sedimentology and environmental geology State Oceanic Administration

The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 kHz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35-250 kHz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafioor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafioor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given.

关键词： Bering Sea Chukchi Sea sound velocity geotechnical properties microstructure

Assessment of structural stability in Bohai Sea area based on AHP-GDM model

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Acta Oceanologica Sinica 2013年第4期32卷 41-48页

作者： XIU Zongxiang LIU Baohua XIE Qiuhong LI Xishuang LIU Chenguang PEI Yanliang ZHENG Yanpeng The First Institute of Oceanography State Oceanic Administration Key Laboratory of Marine sedimentology and environmental geology National Deep Sea Center

The AHP-GDM model is used for the assessment of structural stability, with the Bohai Sea area as an exam- ple. In this model, the credit degree of each expert is calculated through the assessment matrix based on the similarity and diversity of vector. The comprehensive opinions of expert panel are quantitatively obtained by considering the effect ofcredit degree. According to the geological structural setting, the Bohai Sea is di- vided into twelve assessment zones of structural stability by non-uniform element method. The structural stability grade of each zone is obtained on the basis of the latest geophysical data, earthquake statistical data, and the information of fault activities, current stress field and crustal deformation. The results show that there are one relatively stable area, three relatively sub-stable areas, six relatively sub-unstable areas and two relatively unstable areas. The assessment results of non-uniform element method are very close with those of uniform grid method with size of 0.25 in longitude direction and 0.14 in latitude direction. However the workload of non-uniform element method is only 1 / 16 of the latter. Compared with traditional assessment methods of structural stability, a more objective and reliable assessment result can be obtained by combining non-uniform element method and AHP-GDM model.

关键词： AHP-GDM Mode Bohai Sea structural stability non-uniform element method

Geochemistry of rare earth elements in cobalt-rich crusts from the Mid-Pacific M seamount

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Journal of Rare Earths 2009年第1期27卷 169-176页

作者：崔迎春刘季花任向文石学法 Institute of Oceanology Chinese Academy of Sciences Key Lab of Marine sedimentology and environmental geology of State Oceanic Administration First Institute of Oceanography Graduate University of Chinese Academy of Sciences

Rare earth elements（REEs） and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimetric *** results showed that they were hydrogenous crusts with average ∑REE content of 2084.69 μg/g and the light REE（LREE）/heavy REE（HREE） ratio of *** shale-normalized REE patterns showed positive Ce *** total content of strictly trivalent REEs increased with water *** Ce content and LREE/HREE ratios in Fe-Mn crusts above 2000 m were lower than those below 2000 *** change in REE with water depth could be explained by two processes：adsorptive scavenging by setting matters and behaviors of REE in ***, the Ce abundance took no obvious correlation with water depth reflects the constant Ce *** Ce in crusts existed mainly as Ce（IV）, implying that the oxidative-enriching process was controlled by kinetic factors.

关键词： rare earth elements cobalt-rich crusts Mid-Pacific ocean M seamount

Distribution and chemical speciation of dissolved inorganic arsenic in the Yellow Sea and East China Sea

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Acta Oceanologica Sinica 2015年第6期34卷 12-20页

作者： WU Bin SONG Jinming LI Xuegang Key Laboratory of Marine Ecology and environmental Sciences Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Marine sedimentology and environmental geology First Institute of Oceanography State Oceanic Administration

Distribution and chemical speciation of dissolved inorganic arsenic were examined in Yellow Sea and East China Sea. Results demonstrated that：（1） both As（Ⅲ） and As（Ⅴ） were detected, with As（V） dominated at 40% stations of surface water and 51% stations of bottom water; （2） influenced by the exchange of fresh and sea water, the type of surface sediment and the transport of various water masses, large values in surface water were observed along the coastal region and in the same latitude of Changjiang River Estuary and Hangzhou Bay, and in bottom water found in the southern area where the Taiwan Warm Current and Kuroshio Current influenced; （3） As（Ⅲ） behaved non-conservatively in Changjiang River Estuary. Man-derived inputs cause substantial positive deviation from the theoretical dilution. The negative correlation of As（Ⅴ） to salinity in surface water suggested that it behaved conservatively during the transportation along Changjiang River Estuary. While, the occurrence of As（Ⅴ） up to the linear fit in bottom water indicated the eventual transfer from dissolved phase to particulate phase, which was impossible to be determined without the knowledge of arsenic level and speciation in suspended particulate matter. Further study is needed on the arsenic source/sink relationships based on the distribution profiles.

关键词： dissolved inorganic arsenic distribution speciation Yellow Sea East China Sea

Discharge electrode configuration effects on the performance of a plasma sparker

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Plasma Science and Technology 2017年第9期19卷 48-55页

作者：裴彦良张连成黄逸凡严辉朱鑫磊刘振闫克平 Key Laboratory of Marine sedimentology and environmental geology First Institute of OceanographySOA Laboratory for Marine geology Qingdao National Laboratory for Marine Science and Technology Institute of Industrial Ecology and Environment College of Chemical and Biological EngineeringZhejiang University

A multi-electrode array is commonly applied in a plasma sparker to generate stable acoustic *** this paper, the effects of the electrode configuration on the performance of a plasma sparker have been investigated. In terms of the load electrical characteristics, the electrode radius and distance have negligible influence on the electric characteristics, whereas a larger electrode number results in a smaller voltage and a larger current but has little effect on the load energy. Regarding the acoustic characteristics, both the expansion and collapse pulses can be increased by decreasing the electrode tip radius. the influence of the electrode number and electrode gap distance on the amplitude of the expansion pulse was found to be negligible. And the amplitude of the collapse pulse decreases significantly with increasing electrode number. Increasing the electrode number decreases the energy efficiency for intense bubble interactions, thus, a small electrode tip radius and a small electrode number are preferred for the design of a plasma sparker if the total discharge energy is given.

关键词： negligible collapse bubble radius decreasing preferred neglected initially Figure intense

Structural control of the Gagua “Wedge” Zone east of Taiwan Island on the southern Okinawa Trough

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Science China Earth Sciences 2005年第8期48卷 1165-1174页

作者： ZHENG Yanpeng1,2,3, LIU Baohua2,3, WU Jinlong2, LIANG Ruicai2,3, LIU Chenguang2,3 & ZHANG Zhengmin1 1. Marine geology College, Ocean University of China, Qingdao 266003, China 2. First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China 3. Key Laboratory of Marine sedimentology and environmental geology, State Oceanic Administration, Qingdao 266061, China Marine geology College Ocean University of China Qingdao China First Institute of Oceanography State Oceanic Administration Qingdao China Key Laboratory of Marine sedimentology and environmental geology State Oceanic Administration Qingdao China

Based on compositive analysis and interpretation of the observed and historical data, the geophysical field characters and structural properties of the Gagua “Wedge” Zone of the sea area east of Taiwan Island and the primary tectonic stress direction and its variabilities of backarc spreading in the southern Okinawa Trough are studied. It is concluded from the study results that the Gagua “Wedge” Zone is structurally consistent with the Gagua ridge and two fault basins on both sides of the Gagua ridge, and adjusts the moving direction and distance of the western Philippine Sea plate to make the northwestward motion of the plate on its east side change to the northward subduction of the plate on its west side so that the primary tectonic stress direction of the Okinawa Trough changed from NW-SE to nearly N-S, which provided the stress source for the Okinawa Trough to enter the second spreading stage.

关键词： east of Taiwan Island, Gagua "Wedge" Zone, Okinawa Trough, structural control.

environmental record from the mud area on the inner continental shelf of the East China Sea since the mid-Holocene

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Acta Oceanologica Sinica 2011年第4期30卷 43-52页

作者： LIU Shengfa SHI Xuefa LIU Yanguang WU Yonghua YANG Gang First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Key Laboratory of Marine sedimentology and environmental geology State OceanicAdministration Qingdao 266061 China

Paleoclimate record was revealed in Core MZ01 covering the mid-Holocene in age,located in the mud area of the inner continental shelf of the East China Sea. The ancient environment featured low-energy shallow sea shelf deposition formed mainly by coastal currents. The results show that temporal variation in geochemistry corresponds with the climate changes inferred from historical record. Relatively low MgO/Al 2 O 3,CaO/K 2 O and high Al 2 O 3 /Na 2 O,K 2 O/Na 2 O,MnO/CaO values reflected a warm and humid climate in general,and vice versa. Therefore,these chemical indices could be applied to identify the variation of palaeoclimate in eastern China. The authors reconstructed the history of mid-Holocene climatic variation of the inner continental shelf of the East China Sea. From 8 300 a BP to 4 200 a BP,the climate was moderately warm and humid. From 4 200 a BP to 2 000 a BP,the climate turned cool and dry,and the regional climate frequently fluctuated in alternation of cool-dry periods（3 700 a BP,2 850 a BP and 2 400 a BP） and warm-wet periods（3 250 a BP and 2 650 a BP） . After 2 000 a BP,the climate of the study area gradually turned warm again,while the Little Ice Age,a cold event centered at around 250 a BP was indicated by those geochemical indices as mentioned above.

关键词： Holocene East China Sea mud area major element palaeoclimate East Asia monsoon

Distribution of major and trace elements in surface sediments of Hangzhou Bay in China

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Acta Oceanologica Sinica 2012年第4期31卷 89-100页

作者： LIU Shengfa LIU Yanguang YANG Gang QIAO Shuqing LI Chaoxin ZHU Zhiwei SHI Xuefa First Institute of Oceanography State Oceanic AdministrationQingdao 266061China Key Laboratory of Marine sedimentology and environmental geology State OceanicAdministrationQingdao 266061China

The Inductively Coupled Plasma Optical Emission Spectrometer was used to analyze sediment samples collected from the Hangzhou Bay to determine major and trace elemental concentrations. Based on these concentrations, the study area can be classified into three geochemical provinces. Province I covers the northern Hangzhou Bay area and contains high concentrations of A120~, Fe203, MgO, Na20, K20, MnO, Cr, Cu, Ni, Pb, V, Co and Zn. Province III is located in the western Hangzhou Bay, near the Qiantang River mouth, and contains high concentrations of SiO~, Na20, P205~ TiO2, Cr, Sr, Zr. Province II is located in the middle and eastern Hangzhou Bay, with the medium concentrations of major and trace elements. The results also demonstrate that the grain size is the dominating factor controlling the spatial variations of elemental concentrations, and the Changjiang River （Yangtze River） and Qiantang River sediments play an important role in the distribution of these elements. Anthropogenic impact on heavy metal concentrations （especially Cr, Sr and Zr） can be detected in the surface sediments near the Qiantang River mouth.

关键词： Hangzhou Bay Changjiang River sediments major and trace elements grain size,heavy metals

Estimation of potential distribution of gas hydrate in the northern South China Sea

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Chinese Journal of Oceanology and Limnology 2010年第3期28卷 693-699页

作者：王春娟杜德文朱志伟刘永刚闫仕娟杨刚 The First Institute of Oceanography State Oceanic Administration Key Lab of Marine sedimentology & environmental geology of State Oceanic Administration The College of Marine Geosciences Ocean University of China

Gas hydrate research has significant importance for securing world energy resources, and has the potential to produce considerable economic benefits. Previous studies have shown that the South China Sea is an area that harbors gas hydrates. However, there is a lack of systematic investigations and understanding on the distribution of gas hydrate throughout the region. In this paper, we applied mineral resource quantitative assessment techniques to forecast and estimate the potential distribution of gas hydrate resources in the northern South China Sea. However, current hydrate samples from the South China Sea are too few to produce models of occurrences. Thus, according to similarity and contrast principles of mineral outputs, we can use a similar hydrate-mining environment with sufficient gas hydrate data as a testing ground for modeling northern South China Sea gas hydrate conditions. We selected the Gulf of Mexico, which has extensively studied gas hydrates, to develop predictive models of gas hydrate distributions, and to test errors in the model. Then, we compared the existing northern South China Sea hydrate-mining data with the Gulf of Mexico characteristics, and collated the relevant data into the model. Subsequently, we applied the model to the northern South China Sea to obtain the potential gas hydrate distribution of the area, and to identify significant exploration targets. Finally, we evaluated the reliability of the predicted results. The south seabed area of Taiwan Bank is recommended as a priority exploration target. The Zhujiang Mouth, Southeast Hainan, and Southwest Taiwan Basins, including the South Bijia Basin, also are recommended as exploration target areas. In addition, the method in this paper can provide a useful predictive approach for gas hydrate resource assessment, which gives a scientific basis for construction and implementation of long-term planning for gas hydrate exploration and general exploitation of the seabed of China.

关键词： gas hydrate resource assessment northern South China Sea Gulf of Mexico