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The evolution of the Kuroshio Current over the last 5 million years since the Pliocene: Evidence from planktonic foraminiferal faunas

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Science China Earth Sciences 2020年第11期63卷 1714-1729页

作者： Jia WANG Fengming CHANG Tiegang LI Hanjie SUN Yikun CUI Tianhao LIU Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographyMNRQingdao 266061China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Meridional heat transport of the western Pacific boundary current(the Kuroshio Current)is one of the key factors in global climate *** current is important because it controls the temperature gradient between low latitudes and the North Pacific and so significantly influences mid-latitude atmosphere-ocean *** we reconstruct changes in hydrological conditions within the mid-latitude mainstream of the Kuroshio Current based on faunal analysis of planktonic foraminifera in core DSDP 296 from the Northwest Pacific *** approach enabled us to deduce evolutionary processes within the Kuroshio Current since the Pliocene.A total of 57 species in the coarser section(>150μm)were identified;results indicate that planktonic foraminiferal faunal evolution has mainly been characterized by three major stages,the first of which comprised mixed-layer warm-water species of Globigerinoides ruber which first appeared between 3.5 and 2.7 Ma and then gradually increased in *** of another warm-water species of *** also gradually increased in number over this *** in warm-water species indicate a gradual rise in sea surface temperature(SST)and imply initiation of Kuroshio Current impact on the Northwest Pacific Ocean since at least 3.5 ***,over the period between 2.7 and 2.0 Ma,thermocline species of Globigerina calida,Neogloboquadrina humersa,Neogloboquadrina dutertrei,and Pulleniatina obliquiloculata started to appear in the *** fauna was dominated by *** as well as increasing *** *** features imply a further rise in SST and its gradually enhanced influence on thermocline water,suggesting strengthening of the Kuroshio Current since 2.7 ***,between 2.0 Ma and present,increasing contents of thermocline species(i.e.,***,*** and ***)indicate a gradual rise in seawater temperature at this depth and also imply more intensive Kuroshio Current during th

关键词： Pliocene Kuroshio Planktonic foraminifera Western Pacific Warm Pool

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Biomarker reconstruction of phytoplankton productiv-ity and community structure changes in the middle Okinawa Trough during the last 15 ka

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Chinese Science Bulletin 2008年第16期53卷 2552-2559页

作者： XING Lei ZHAO MeiXun ZHANG HaiLong LIU YanGuang SHI XueFa Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Qingdao 266100China Sate Key Laboratory of Marine Geology School of Ocean and Earth Science Tongji University Shanghai 200092 China Key Laboratory of Marine sedimentology and Environmental Geology State oceanic AdministrationFirst Institute of Oceanography State Oceanic Administration Qingdao 266061 China

Biomarkers have been widely used to reconstruct phytoplankton productivity and community structure changes, and this method has been applied for the first time in the middle Okinawa Trough during the transition from the last deglaciation to the Holocene. The total content of all marine phytoplankton biomarkers, used as a total productivity indicator, reveals higher productivity during the deglaciation. The ratios of the biomarkers are used as community structure indicators which show that, compared with the Holocene, the contribution from haptophytes decreased while the contributions from diatoms and dinoflagellates increased during the deglaciation. The increased productivity during the deglacia- tion was likely caused by the stronger winter monsoon. Also increased nutrient supply from terrestrial sources contributes to the higher productivity due to lower sea-level, which is consistent with higher terrestrial biomarker (long-chain n-alkanols) content. These changes in the nutrient supply also con- tributed to the community structure changes in the Okinawa Trough.

关键词：浮游植物生物标记重建社区结构变化冰川消失

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Characterization of Alluvial Gold Bearing Sediments of Betare Oya District-East Cameroon, Implication for Gold Exploration and Recovery

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Open Journal of Geology 2017年第11期7卷 1724-1738页

作者： Germain Marie Monespérance Mboudou Kennedy Folepai Fozao Olivier Annoh Njoh Christopher Mbaringong Agyingi Economic Geology Unit Department of Geology University of Buea Buea Cameroon sedimentology and Petroleum Geolgy/Engineering Unit Department of Geology University of Buea Buea Cameroon

Field studies (location Au pits, sampling of different layers of sedimentary sequences filling the pits, panning of sediments), litho-stratigraphic investigations, grain size analysis and outlining of depositional conditions revealed a characteristic fining upward sequence in all the sections of 08 Au-pits within the Betare Oya basin. A typical profile is 2.5 to 4.5 m thick and is composed of a 30 to 50 cm organic topsoil layer, underlain by a 1.5 m thick reddish brownish gold free saprolite, which is underlain by 1.5 m sandy section. from litho-stratigraphic investigations and grain size analysis results a quartz dominated gravelly 1.4 m thick layer consisting in boulders (275 mm), cobbles (2-−0.0148x2 + 1.2187x + 2.0344, R2 = 0.6929 (sandy layer);2) y = 0.0617x2 + 1.0849x + 0.8097, R2 = 0.8694 (gravelly layer);and y > R2 is satisfied in both cases. This implies that Au recovery from these layers could be effective through gravity separation using sieves mounted on classifiers of 7 cm (sandy layer) and 10 cm (gravelly layer) diameter.

关键词： Betare Oya Aspect Ratios Au Grains Yield Alluvial Sediments Pull-Apart Basin

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Sea-surface acoustic backscattering measurement at 6–25 kHz in the Yellow Sea

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Acta Oceanologica Sinica 2020年第3期39卷 113-122页

作者： Lehua Qi Guangming Kan Baohua Liu Yanliang Pei Zhiguo Yang Shengqi Yu College of Marine Geo-sciences Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China National Deep Sea Center State Oceanic AdministrationQingdao 266237China

Sea-surface acoustic backscattering measurements at moderate to high frequencies were performed in the shallow water of the south Yellow Sea, using omnidirectional spherical sources and omnidirectional hydrophones. Sea-surface backscattering data for frequencies in the 6–25 k Hz range and wind speeds of(3.0±0.5)and(4.5±1.0) m/s were obtained from two adjacent experimental sites, respectively. Computation of sea-surface backscattering strength using bistatic transducer is described. Finally, we calculated sea-surface backscattering strengths at grazing angles in the range of 16°–85°. We find that the measured backscattering strengths agree reasonably well with those predicted by using second order small-roughness perturbation approximation method with "PM" roughness spectrum for all frequencies at grazing angles ranged from 40° to 80°. The backscattering strengths varied slightly at grazing angles of 16°–40°, and were much stronger than roughness scattering. It is speculated that scattering from bubbles dominates the backscattering strengths at high wind speeds and small grazing angles. At the same frequencies and moderate to high grazing angles, the results show that the backscattering strengths at a wind speed of(4.5±1.0) m/s were approximately 5 d B higher than those at a wind speed of(3.0±0.5) m/s. However, the discrepancies of backscattering strength at low grazing angles were more than 10 d B. Furthermore the backscattering strengths exhibited no significant frequency dependence at 3 m/s wind speed. At a wind speed of 4.5 m/s, the scattering strengths increased at low grazing angles but decreased at high grazing angles with increasing grazing angle.

关键词： sea-surface acoustic scattering moderate frequency scattering model bistatic backscattering frequency dependence

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Nd isotope as the tracer of seawater evolution of early Miocene in the eastern Pacific Ocean

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Chinese Science Bulletin 2003年第B6期48卷 106-110页

作者： LIU Jihua~(1,2,3), CHEN Lirong~1, WANG Yingxi~4 & HAN Jianxiu~5 1. Institute of Oceanology, Chinese Acadcmy of ences, Qingdao 266071. China 2. Key Lab of Marine sedimentology and Environmental Geology, First Institute of Oceanograpgy, State Oceanic Administration, Qingdao 266061. China 3. Graduate School, Chinese Academy of Sciences, Beijing 100039. China 4. Modern Analysis Center, Nanjing University. Nanjing 210093. China 5. Guangzhou Marine Investigation Bureau, Guangzhou 510760. China Institute of Oceanology Chinese Academy of Sciences Qingdao China Key Lab of Marine sedimentology and Environmental Geology First Institute of Oceanograpgy State Oceanic Administration Qingdao China Graduate School Chinese Academy of Sciences Beijing China Modern Analysis Center Nanjing University Nanjing China Guangzhou Marine Investigation Bureau Guangzhou China

Fifty-six samples of nannofossil ooze were collected from Core PC5794 in the northern equatorial Pacific at 5 cm intervals. With the methods of mass spectrometer (VG354) and ICP, the Nd isotopic compositions (εNd(t)), Mn contents and Mg/Sr ratios of carbonate phase have been analyzed. CaCO3 contents of bulk sediments were obtained by dissolution of 0.5 mol/L HCl. Based on these data, the high-resolution εNd(t) profile of seawater in early Miocene with core depth(or time) have been established. The values of εNd(t) range from -6.2 to -2.97 and 4 fluctuation cycles existed during 24.06-22.02 Ma. 4 low εNd(t) values (about -6.4) correspond to high CaCO3 contents, which implicates that there were 4 cold epochs or 4 times of Antarctic Bottom Water activity. They occurred at the time of 24.06 Ma, 23.85 Ma,22.88 Ma and 22.26 Ma, respectively. High εNd(t) values correspond to the high Mn contents and high values of Mg/Sr ratio, which indicates the existence of 4 intense hydrothermal activity periods during 24.06-22 Ma, the durations of them are 4.05-23.98 Ma, 23.69-23.15 Ma, 22.74-22.37 Ma and 22.06-22.02 Ma, respectively.

关键词：同位素钕示踪原子海水演化中新世太平洋微化石分光计持续期海水样品

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Development and application of a GIS-based artificial neural network system for water quality prediction: a case study at the Lake Champlain area

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Journal of Oceanology and Limnology 2020年第6期38卷 1835-1845页

作者： LU Fang ZHANG Haoqing LIU Wenquan Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266000China Key Laboratory of Marine Environment and Ecology Ministry of EducationQingdao 266100China Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural Resources(MNR)Qingdao 266061China

Artificial Neural Network(ANN)models have been extensively applied in the prediction of water resource variables,and Geographical Information System(GIS)includes powerful functions to visualize spatial *** order to provide an efficient tool for environmental assessment and management that combines the advantages of these two modules,a GIS-based ANN water quality prediction system was developed in the present *** ANN module and ArcGIS Engine module,along with a dynamic database,were imbedded in the system,which integrates water quality prediction via the ANN model and spatial presentation of the model *** structure of the ANN model could be modified through the graphical user interface to optimize the model *** developed system was applied to a real case study for the prediction of the total phosphorus concentration in the Lake Champlain *** prediction results were verified with the monitoring data,and the performance of the developed model was further evaluated through graphical techniques and quantitative statistical ***,the developed system provided satisfactory prediction results,and spatial distribution maps of the predicted results were obtained,which coincided with the monitored *** developed GIS-based ANN water quality prediction system could serve as an efficient tool for engineers and decision makers.

关键词： water quality prediction Geographical Information System(GIS) artificial neural network integration system development

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Implications of the melting depth and temperature of the Atlantic mid-ocean ridge basalts

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Acta Oceanologica Sinica 2019年第12期38卷 35-42页

作者： Yili Guan Xuefa Shi Quanshu Yan Xun Wei Yan Zhang Xiaoping Xia Haoda Zhou Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266061China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Zhuhai Central Station of Marine Environmental Monitoring State Oceanic AdministrationZhuhai 519015China

Mid-ocean ridge basalts(MORBs) are characterized by large variations in trace element compositions and isotopic ratios, which are difficult to be interpreted solely by using magmatic process such as partial melting of a peridotitic mantle and subsequently fractional crystallization. Geochemical diversity of MORBs have been attributed to large-scale heterogeneity within the underlying mantle, and the heterogeneity might have been caused by addition of recycled crustal component, subcontinental lithosphere, metasomatized lithosphere and outer core contribution. In this study, we investigated the MORBs along the Mid-Atlantic Ridge(MAR) by estimating the temperature and pressure of partial melting, and comprehensively comparing trace element and isotope ratios. The data for MORBs from areas close to mantle plumes show large variations. Mantle plumes can affect mid-oceanic ridges 1 400 km away, but plume effects did not cover all of the ridge segments, and those segments without plume effects did not have any abnormalities in temperature, trace element or isotope *** ascribed the above phenomena to result from the shapes of the plume flow, which we categorized as "pipelike channels" and "pancake-like channels". The "pancake-like channels" plumes affected the ambient mantle nondirectionally, but the range of the mantle affected by the "pipe-like channels" plumes were selective. Element ratios of MORBs reveal that the mantle source of the MORBs along the MAR is highly heterogeneous. We suggest that most of source heterogeneities of the MORBs may be due to the presence of subducted slab and delaminated lower crust in the source. In addition, the plume that carried materials from the core-mantle boundary may affect some of the segments.

关键词： Mid-Atlantic Ridge MORB mantle heterogeneity plume-ridge interaction

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Reef-controlled Mineral Deposits in Southern China

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Acta Geologica Sinica(English Edition) 1989年第3期63卷 241-252页

作者： Zeng Yunfu and Tian Hongjun Chengdu College of Geology, Chengdu Chengdu College of Geology Chengdu 1This paper was based on the related research results achieved in recent years by the Institute of sedimentology of Chengdu College of Geology. Besides the authors Zhang Jinquan Zheng Rongcai Xu Xinhuang Tang Dezhang Geng Aiqin Yang Weidong and Chen Zhihong also made large amounts of work. The authors also used the data of Zhou Huailing Shi Huanqi and Hu Chunsheng of the Guangxi Bureau of Geology and Mineral Resources.

Reef-controlled mineral deposits in southern China are divided into three types in this paper based on the relative importance of organic reefs in the ore-forming processes; they are: the direct type, indirect type, and passive type. The case histories of several typical deposits are discussed. In studying reef-controlled deposits, more attention should be paid to the function of synsedimentary faults in reef construction and mineralization and the importance of oil-gas palaeoreservoirs in reef rocks for the formation of sulfide deposits, in addition to analysing the favourable sedimentary facies of mineralization.

关键词： Reef-controlled Mineral Deposits in Southern China

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Response of Terrigenous Sediment Input to Sea Level Change and East Asian Monsoon Evolution Since 30kyr in the Southwestern Taiwan Basin

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Journal of Ocean University of China 2021年第3期20卷 539-552页

作者： FENG Li FENG Xiuli TANG Rong XIAO Xiao LIU Jie College of Marine Geosciences Ocean University of ChinaQingdao 266100China Key Laboratory of Submarine Geosciences and Prospecting Techniques MOEQingdao 266100China The First Monitoring and Application Center China Earthquake AdministrationTianjin 300171China Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

The compositions of grain size,clay minerals,and geochemical elements in core sediments(TS4)from the southwestern Taiwan Basin(South China Sea)were investigated to assess the response of terrigenous sediment input to sea level change and the East Asian monsoon evolution since 30 *** chronology was discussed based on foraminiferal AMS14C *** results indi-cated that rivers in Taiwan have been the major sediment contributors since 30 kyr,followed by the Pearl River;and Luzon Island contribute little sediments to the southwestern Taiwan *** this study,we reconstructed the variations in terrigenous sediment input by using the proxies such as Al2O_(3)(%),F1 score,and TiO_(2)/*** F1 score can be used to indicate the flux of terrigenous *** contribution of Taiwan Residents rivers and the Pearl River were evaluated by using the value of(illite+chlorite)/*** variations of Al2O_(3)(%),F1 score,and TiO_(2)/CaO values along the core were clearly correlated to the evolution of the East Asian summer monsoon since 30 *** on these records,we recognized three evolutionary stages of terrigenous sediment input in the southwestern Taiwan *** stage Ⅰ(29-24kyr),the input of terrigenous sediments continued to *** stage Ⅱ(24-11.5 kyr),the sediment input decreased at first and then increased,with the lowest value during the last glacial period(21-17kyr).Terrigenous sediment input during stage Ⅲ(11.5 kyr-)showed the decreasing first and then increasing trends,generally higher than those in the first and second *** variations of terrigenous sediment input in the study area corresponded well with the evolu-tion of the East Asian summer monsoon since 30 *** terrigenous sediment input during 4-1.8 kyr was suggested to be caused by the enhanced ENSO *** level change does not alter the overall trend of terrigenous sediment input,but does change the relative contributions of rivers in Taiwan and the Pearl Riv

关键词： grain size geochemical elements clay minerals sediment provenance terrigenous sediment input

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Post-Rifting Magmatism and the Drowned Reefs in the Xisha Archipelago Domain

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Journal of Ocean University of China 2018年第1期17卷 195-208页

作者： WANG Hongli ZHAO Qiang WU Shiguo WANG Dawei WANG Bin Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Key Laboratory of Marine sedimentology and Environmental Geology First Institute of OceanographySOA Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Laboratory of Marine Geophysics and Deep-Sea Georesources Institute of Deep-Sea Science and Engineering Chinese Academy of Sciences Hangzhou Institute of Petroleum Geology PetroChina

Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr^(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E).

关键词： magmatism tectonic subsidence drowned reef Xisha Archipelago

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