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Science China Earth Sciences 2003年第2期46卷 139-148页

作者：魏泽勋方国洪崔秉昊方越何宜军 Institute of Oceanology Chinese Academy of Sciences Department of Civil and Environment Engineering Sung Kyun Kwan University Department of Oceanography Texas A & M University College Station

A fine-grid model (1/6) covering the South China sea (SCS), East China sea and Ja-pan/East sea, which is embedded into a coarse-grid (3) global model, was established to study the SCS circulation. In the present paper, we report the model-produced monthly and annual mean transport stream functions and sea surface heights(SSH) and their anomalies of the SCS. Com-parison to the TOPEX/Poseidon data shows that the model-produced monthly sea surface height anomalies (SSHA) are in good agreement with altimeter measurements. Based on the results, the circulation of the SCS, especially the upper layer circulation, is discussed. In the surface layer, the western Philippine sea water intrudes into the SCS through the Luzon Strait in autumn, winter and spring, but not in summer. However, as far as the whole water column is concerned, the water in-trudes into the SCS through the Luzon Strait all the year round. This indicates that in summer the water still intrudes into the SCS in the subsurface and intermediate layers. The area near the northern continental slope of the SCS is dominated by a cyclonic circulation all the year round. The SCS Southern Anticyclonic Gyre, SE Vietnam Off-Shore Current in summertime and SCS South-ern Cyclonic Gyre in wintertime are reproduced reasonably. The difference between the monthly averaged SSH and SSHA is significant, indicating the importance of the mean SSH in the SCS circulation.

关键词： South China sea, sea surface height, sea surface height anomaly, transport stream function, numerical model.

Responses of foraminiferal isotopic variations at ODP Site 1143 in the southern South China sea to orbital forcing

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Science China Earth Sciences 2004年第10期47卷 943-953页

作者： TIAN Jun WANG Pinxian CHENG Xinrong Laboratory of Marine Geology Tongji University Shanghai 200092 China Laboratory of Marine Geology Tongji University Shanghai 200092 China Laboratory of Marine Geology Tongji University Shanghai 200092 China

The foraminiferal δ 18O and δ 13C records for the past 5 Ma at ODP Site 1143 reveal the linear responses of the Plio-Pleistocene climatic changes in the southern South China sea to orbital forcing at the obliquity and precession bands. The phase of the δ 18O variations with the orbital forcing is opposite to that of the δ 13C, which may be caused by the frequent El Ni?o events from the equatorial Pacific. The amplification of the Northern Hemisphere Ice Sheet at ?3.3 Ma probably affected the development of the 100-ka climatic cycles. Its further spreading may spur the 100-ka climatic cycle to become the dominant cycle in the late Pleistocene. The “Mid- Pleistocene Transition” event has localized influence on the isotopic variations in the southern South China sea. The foraminiferal δ 13C records for the past 5 Ma at Site 1143 are highly coherent with the orbital forcing at the long eccentricity band, and lead the δ 18O records at the shorter eccentricity band, highlighting the importance of the carbon cycle in the global climate change.

关键词： southern South China sea, ODP, oxygen and carbon isotope, orbital forcing.

Mesozoic subduction-accretion zone in northeastern South China sea inferred from geophysical interpretations

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Science China Earth Sciences 2006年第5期49卷 471-482页

作者： ZHOU Di1, WANG Wanyin2, WANG Jialin3, PANG Xiong4, CAI Dongsheng5 & SUN Zhen1 1. Key Laboratory of Marginal sea Geology, South China sea Institute of Oceanology, Chinese Academy of Sciences, Guang- zhou 510301, China 2. College of Geological and Topographical Engineering, Chang’an University, Xi’an 710054, China 3. Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 4. China National Offshore Oil Co. Limited – Shenzhen Branch, Shenzhen 518067, China 5. China National Offshore Oil Co. Limited – Research Center, Beijing 100027, China 1. Key Laboratory of Marginal sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China 2. College of Geological and Topographical Engineering Chang’an University Xi’an 710054 China 3. Key Laboratory of Marine Geology Tongji University Shanghai 200092 China 4. China National Offshore Oil Co. Limited — Shenzhen Branch Shenzhen 518067 China 5. China National Offshore Oil Co. Limited — Research Center Beijing 100027 China

A segment of Mesozoic subduction-accretion zone was inferred across thenortheastern South China sea at approximately NE450 orientation. Basic evidence includes thefollowing: A belt of peek gross horizontal Bouguer gravity gradient (PGHGBA) is comparable in sizeand intensity to that of the Manila subduction-accretion zone. A belt of high positive magneticanomalies appears to the north and sub-parallel to the PGHGBA, representing the volcanic arcassociated to the subduction zone. The PGHGBA crosses obliquely both Cenozoic structures and presentseafloor topography, indicating a pre-Cenozoic age. The segment is offset left-laterally byNW-running strike-slip faults, in concord with the Mesozoic stress field of South China. Inaddition, the existence of the subduction zone is supported by wide-angle seismic data obtained indifferent years by different institutions. At approximate localities, a north-dipping ramp of Mohosurface is indicated by records of ocean-bottom seismometers, and a strong reflector about 8 kmbeneath the Moho reflector is indicated by both OBS and long-cable seismic records. Theidentification of a segment of Mesozoic subduction zone in NE South China sea fills nicely the gapof the Great Late Mesozoic Circum SE Asia Subduction-acrretion Zone, which extended from Sumatra,Java, SE Kalimantan to N Palawan, and from Taiwan, Ryukyu to SW Japan.

关键词： Mesozoic, subduction zone, SE Asia, NE South China sea, geophysics.

Annual variation of sea surface height, dynamic topography and circulation in the South China sea —— A TOPEX/Poseidon satellite altimetry study

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Science China Earth Sciences 2003年第2期46卷 127-138页

作者：李立许金电靖春生吴日升郭小钢 The Third Institute of Oceanography State Oceanic Administration

TOPEX/Poseidon satellite altimetry data from 1993 to 1999 were used to study mean annual variation of sea surface height anomaly (SSHA) in the South China sea (SCS) and to re-produce its climatological monthly surface dynamic topography in conjunction with historical hy-drographic data. The characters and rules of seasonal evolution of the SCS dynamic topography and its upper circulation were then discussed. Analyses indicate that annual variation of the SCS large-scale circulation could be divided into four major phases. In winter (from November to Feb-ruary), the SCS circulation is mainly controlled by double cyclonic gyres with domination of the northern gyre. Other corresponding features include the Kuroshio intrusion from the Luzon Strait and the northeastward off-shelf current in the area northwest off Kalimantan Island. The double gyre structure disassembled in spring (from March to April) when the northern gyre remains cyc-lonic, the southern gyre becomes anticyclonic, and the general circulation pattern shows a dipole. There is no obvious large-scale closed gyre inside the SCS basin in both summer (from May to July) and autumn (from August to October) when the SCS Monsoon Jet dominates the circulation, which flows northeastward across the SCS. Even so, circulation patterns of these two phases di-verse significantly. From May to July, the SCS monsoon jet flows northward near the Vietnam coast and bends eastward along the topography southeast off Hainan Island at about 18N form-ing an anticyclonic turn. It then turns northeastward after crossing the SCS. From August to Octo-ber, however, the monsoon Jet leaves the coast of Vietnam and enters interior of the basin at about 13N, and the general circulation pattern becomes cyclonic. The Kuroshio intrusion was not obvious in spring, summer and autumn. It is suggested from these observations that dynamic ad-justment of the SCS circulation starts right after the peak period of the prevailing monsoon.

关键词： South China sea, satellite altimetry, sea surface height, dynamic topography, circulation.

Disequilibria between ^(210)Po and ^(210)Pb in surface waters of the southern South China sea and their implications

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Science China Earth Sciences 2006年第1期49卷 103-112页

作者： YANG Weifeng, HUANG Yipu1,2, CHEN Min1,2, ZHANG Lei, LI Hongbin, LIU Guangshan1,2 & QIU Yusheng1,2 1. Department of Oceanography, Xiamen University, Xiamen 361005, China 2. State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China 1. Department of Oceanography Xiamen University Xiamen 361005 China 2. State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China

Activities of the naturally occurring radionuclides, ^(210)Pb and ^(210)Po,were measured in both dissolved ( 0.45 μm) phases from surfacewaters of the southern South China sea. The average activity of particulate ^(210)Pb, 0.23 Bq/m^3 (n= 23), accounted for about 12% of the total ^(210)Pb, which corresponds with values of open *** ^(210)Po, with an average activity of 0.43 Bq/m^3, accounted for about 40% of the total^(210)Po, which was much higher than those of open and eutrophic oceans. The residence times oftotal ^(210)Po and ^(210)Pb in surface waters estimated from an irreversible steady-state model were0.82 a and 1.16 a, respectively. The consistently high fractionation factor calculated either byscavenging rate constants (5.42) or K_d values (6.69) suggested that a significant fractionationoccurred between ^(210)Po and ^(210)Pb during their removal from solution to particles and that thetwo radionuclides had different biogeochemical cycling pathways in the oligotrophic South China ***, our results indicated that there exist different fractionation mechanisms between^(210)Po and ^(210)Pb in different marine environments: in eutrophic ocean, plankton detritus andfecal pellets are the main carrier of ^(210)Po and ^(210)Pb, by which ^(210)Po and ^(210)Pb havebeen scavenged and removed; while in oligotrophic ocean, microbes could become the main carrier of^(210)Po and fractionate ^(210)Po and ^(210)Pb significantly as a result of scarce plankton detritusand fecal pellets. These results suggest the use of ^(210)Po to trace marine biogeochemicalprocesses relating to microbial activities and the cycling of sulfur group elements (S, Se, Te andPo).

关键词： South China sea, 210Po, 210Pb, disequilibria, scavenging.

Grain-size records at ODP Site 1146 from the northern South China sea: Implications on the East Asian monsoon evolution since 20 Ma

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Science China Earth Sciences 2007年第10期50卷 1536-1547页

作者： Jan-Berend W. STUUT Research Center Ocean Margins Bremen University Bremen 28334 Germany

273 samples from Ocean Drilling Program (ODP) Site 1146 in the northern South China sea (SCS) were analyzed for grain-size distributions using grain-size class vs. standard deviation method and end-member modeling algorithm (EMMA) in order to investigate the evolution of the East Asian monsoon since about 20 Ma. 10–19 μm/1.3–2.4 μm, the ratio of two grain-size populations with the highest variability through time was used to indicate East Asian winter monsoon intensity relative to summer monsoon. The mass accumulation rate of the coarsest end member EM1 (eolian), resulting from EMMA, can be used as a proxy of winter monsoon strength and Asian inland aridity, and the ratio of EM1/(EM2+EM3) as a proxy of winter monsoon intensity relative to summer monsoon. The combined proxies show that a profound enhancement of East Asian winter monsoon strength and winter monsoon intensity relative to summer monsoon occurred at about 8 Ma, and it is possible that the summer monsoon simultaneously intensified with winter monsoon at 3 Ma. Our results are well consistent with the previous studies in loess, eolian deposion in the Pacifc, radiolarians and planktonic foraminifera in the SCS. The phased uplift of the Himalaya-Tibetan Plateau may have played a significant role in strengthening the Asian monsoon at 8 Ma and 3 Ma.

关键词： grain size, eolian dust, East Asian monsoon, South China sea, ODP Leg184

Current measurements and spectral analyses in the upper 450 m and deep layers of the northeastern South China sea

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Science China Earth Sciences 2002年第11期45卷 1008-1026页

作者：袁耀初赵进平王惠群楼如云陈洪王康墡

On the basis of the current measurements from the moored Long Ranger ADCP in the upper 450 m layer and the deep current measurements at 2000 and 2300 m from the moored current meters with the time series data of about 7 months at the mooring station in the northeastern South China sea, the spectral analyses and calculation have been made. The major results are as follows: (i) From the progressive vector diagrams of the observed daily currents at the water levels from 50 m to 400 m, its temporal variation of velocity rotated counterclockwise in most of the observing time. This agrees basically with the result from the qualitative analysis of the sea surface height data, which was obtained from TOPEX/ERS-2 altimeter data by CCAR. The daily and monthly average velocities are both the largest in November, next in October and minimum in August. (ii) At the 2000 and 2300 m levels, the daily and monthly average velocities are both the largest in January, next in September and minimum in August. From the seasonal change of currents, the current velocity is the strongest in winter (January-March), next in autumn, and weak in summer. (iii) There exists the variation of tidal current with the change of depth. In the upper layer, the height of diurnal peak is higher than that of semidiurnal peak. However, the semidiurnal peak is higher than the diurnal peak at the levels from 200 m to 400 m. In the layers above 450 m the clockwise component is dominant in their fluctuations. In the layers below 1500 m the diurnal peak is again higher than the semidiurnal peak. (iv) There is the prominent periodic fluctuation of more than two months in the layer from 50 m to 2300 m. The period of this prominent peak is 75 d and its fluctuation is counterclockwise in the upper 450 m layers, and is 68 d and 69 d at the depths of 2000 and 2300 m, respectively, and the counterclockwise component is dominant in their fluctuations. (v) There are the variations of periods fluctuating with the change of

关键词： northeastern South China sea, current measurement in the upper 450 m layer, current measurement in the deep layer, spectral analysis, fluctuation of long period.

REE geochemistry of surface sediments in the Chukchi sea

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Science China Earth Sciences 2003年第6期46卷 603-611页

作者：陈志华高爱国刘焱光孙海清石学法杨作升 KeyLaboratoryofMarineSedimentologyandEnvironmentalGeology StateOceanicAdministration FirstInstituteofOceanography StateOceanicAdministrationQingdao266061China OceanUniversityofQingdao Qingdao266003China FirstInstituteofOceanography StateOceanicAdministration OceanUniversityofQingdao

Analyses of rare earth elements (REEs) in 26 surface sediment samples obtained from the Chukchi sea were conducted using ICP-MS. In general, REEs are relatively rich in fine-grained sediments and deplete in coarse-grained sediments in the Chukchi sea although REEs have large concentration spans in different types of sediments. Except that a few samples have weak en-richments of light or heavy REEs?most samples exhibit flat shale-normalized REE pattern, indi-cating that surface sediments in the Chukchi sea are composed dominantly of terrigenous com-ponents experiencing weak chemical weathering. In terms of REE concentrations and other char-acteristic parameters, we inferred that sediments on the eastern and western sides of the Chukchi sea are derived from landmasses of Alaska and Siberia, respectively; the midsouth sediments are possibly related to northward dispersion of the Yukon River materials. The Herald Shoal in the center of the study area is covered with relict sediment, which has large ratios of light-to-heavy REEs (ΣCe/ΣY ratio) and lacks evident negative Ce anomaly; cerium enrichment is possibly re-lated to manganese transfer under oxidizing conditions in early diagenesis.

关键词： Chukchi sea, surface sediments, rare earth elements.

Paleoceanographic evolution recorded in the northern South China sea since 4 Ma

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Science China Earth Sciences 2005年第12期48卷 2166-2173页

作者： HUANG Baoqi1,2, JIAN Zhimin2 & WANG Pinxian2 1. School of Earth and Space Sciences, Peking University, Beijing 100871, China 2. Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 1. School of Earth and Space Sciences Peking University 100871 Beijing China 2. Laboratory of Marine Geology Tongji University 200092 Shanghai China

Upper water structure over the last 4 million years in the northern South China sea (SCS) was reconstructed by sea surface temperature (SST) and primary productivity estimated by changes in the abundance of planktonic foraminifer, planktonic foraminifer transfer function, and the accumulation rate of benthic foraminifera. Results of SST and primary productivity show that SST gradually decreased since 4 Ma, but differential seasonal temperature and primary productivity increased in steps mainly at about 3.1, 2.7, 2.1, 1.6, 0.9 and 0.5 Ma. Comparison with tectonics and orbital variations indicates that phased rising of the Tibet since 3.6 Ma, closing of Panama and Indonesian seaways, and orbital changes were responsible for the changes of upper water structure in the SCS, respectively.

关键词： northern South China sea, upper water structure, Late Pliocene, planktonic foraminifer, ODP 1146.

Distribution of ^(226)Ra in the Arctic Ocean and the Bering sea and its hydrologic implications

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Science China Earth Sciences 2003年第5期46卷 516-528页

作者：邢娜陈敏黄奕普蔡平河邱雨生 DepartmentofOceanography XiamenUniversity

Radium-226 (226Ra) activities were measured in the surface water samples collected from the Arctic Ocean and the Bering sea during the First Chinese National Arctic Research Ex-pedition. The results showed that 226Ra concentrations in the surface water ranged from 0.28 to 1.56 Bq/m3 with an average of 0.76 Bq/m3 in the Arctic Ocean, and from 0.25 to 1.26 Bq/m3 with an average of 0.71 Bq/m3 in the Bering sea. The values were obviously lower than those from open oceans in middle and low latitudes, indicating that the study area may be partly influenced by sea ice meltwater. In the Bering sea, 226Ra in the surface water decreased northward, probably as a result of the exchange between the 226Ra-deficient sea ice meltwater and the 226Ra-rich Pacific water. In the Arctic Ocean, 226Ra in the surface water increased northward and eastward. This spa-tial distribution of 226Ra reflected the variation of the 226Ra-enriched river component in the water mass of the Arctic Ocean. The vertical profiles of 226Ra in the Canadian Basin showed a concen-tration maximum at 200 m, which could be attributed to the inputs of the Pacific water or/and the bottom shelf water with high 226Ra concentration. This conclusion was consistent with the results from 2H, 18O tracers.

关键词： Arctic Ocean, Bering sea, 226Ra, distribution.