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Registros recuperados: 24 | |
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Wang, Xudong; Li, Niu; Feng, Dong; Hu, Yu; Bayon, Germain; Liang, Qianyong; Tong, Hongpeng; Gong, Shanggui; Tao, Jun; Chen, Duofu. |
Cold seeps frequently occur at the seafloor along continental margins. The dominant biogeochemical processes at cold seeps are the combined anaerobic oxidation of methane and sulfate reduction, which can significantly impact the global carbon and sulfur cycles. The circulation of methane-rich fluids at margins is highly variable in time and space, and assessing past seepage activity requires the use of specific geochemical markers. In this study, we report multiple sedimentary proxy records for three piston gravity cores (QDN-14A, QDN-14B, and QDN-31) from the Haima seep of the South China Sea (SCS). By combining total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), total sulfur (TS), acid insoluble carbon and sulfur isotope... |
Tipo: Text |
Palavras-chave: Cold seep; Anaerobic oxidation of methane; Carbon and sulfur isotopes; South China Sea. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00465/57662/59858.pdf |
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Zheng, Xufeng; Kao, Shuhji; Chen, Zhong; Menviel, Laurie; Chen, Han; Du, Yan; Wan, Shiming; Yan, Hong; Liu, Zhonghui; Zheng, Liwei; Wang, Shuhong; Li, Dawei; Zhang, Xu. |
Deepwater circulation plays a central role in global climate. Compared with the Atlantic, the Pacific deepwater circulation's history remains unclear. The Luzon overflow, a branch of the North Pacific deep water, determines the ventilation rate of the South China Sea (SCS) basin. Sedimentary magnetic properties in the SCS reflect millennial-scale fluctuations in deep current intensity and orientation. The data suggest a slightly stronger current at the Last Glacial Maximum compared to the Holocene. But, the most striking increase in deep current occurred during Heinrich stadial 1 (H1) and to a lesser extent during the Younger Dryas (YD). Results of a transient deglacial experiment suggest that the northeastern current strengthening at the entrance of the... |
Tipo: Text |
Palavras-chave: South China Sea; Deep current; Anisotropy of magnetic susceptibility; Heinrich 1; Atlantic-Pacific seesaw. |
Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53224/54800.pdf |
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Yu, Pai-sen; Mii, Horng-sheng; Murayama, Masafumi; Chen, Min-te. |
Marine sediment core MD012394 from the Vietnam coastal upwelling area in the western South China Sea was investigated in order to reconstruct the last Quaternary monsoon upwelling based on planktic foraminifer fauna assemblages and faUna-based sea surface temperature (SST) estimates. The age model of core MD012394 was constructed using oxygen isotope stratigraphy of the planktic foraminifer G. sacculifer, with 10 accelerator mass spectrometry (AMS) 14 C dating of planktic foraminifers from the sediment samples. Our studies on the relative and absolute abundances of planktic foraminifer assemblages reveal eight dominant species in core MD012394: N. dutertrei + N. pachyderma (right coiling), G. ruber, G. glutinata, G. sacculifer, P obliquiloculata, G.... |
Tipo: Text |
Palavras-chave: South China Sea; Planktonic foraminifer fauna; Sea surface temperature; East Asian monsoon; Summer insolation. |
Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34816/33681.pdf |
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Chen, Guocheng; Zheng, Hongbo; Li, Jianru; Xie, Xin; Me, Xi. |
High-resolution oxygen isotope stratigraphy of Core MD05-2901, which is located off eastern Vietnam in the western South China Sea (SCS), was established and indicated that the core spans a time period of the past 450 ka. Based on the bulk density, fractional porosity and lithogenic content of the sediments, terrigenous mass accumulation rate (TMAR) was obtained, which is 4.9-6.0 g cm(-2) ka(-1) on average during interglacial stages, higher than that during glacial stages, i.e. 1.9-5.0 g cm(-2) ka(-1), which is different from northern and southern SCS which show higher TMAR in glacial stages. By principle component analysis of grain size distribution of all the samples, two main control factors (F1 and F2) were obtained, which are responsible for about 80%... |
Tipo: Text |
Palavras-chave: South China Sea; Late Quaternary; Terrigenous sediments; Grain size; East Asian monsoon. |
Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00207/31846/30290.pdf |
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Wan, Sui; Jian, Zhimin. |
Deep ocean circulation is widely considered as one of the important factors for increasing CO2 concentration and decreasing radiocarbon activity (C-14) of the atmosphere during the last deglaciation. The AMS C-14 ages of benthic and planktonic foraminifers from 18 samples of Core MD05-2904 (water depth of 2066m) in the northern South China Sea (SCS) and 15 samples of Core MD05-2896 (water depth of 1657m) in the southern SCS were analyzed in this study for reconstructing the intrabasin deep oceanic processes and hence exploring the deep water exchanges between the SCS and the Pacific since the last glacial period. The results show that during the Holocene the average apparent ventilation age of deep water was younger in the southern SCS (1350years) than in... |
Tipo: Text |
Palavras-chave: Deep water renewal; AMS 14C dating; Last glacial cycle; South China Sea. |
Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40040/39257.pdf |
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Huang, Cy; Wang, Cc; Zhao, Mx. |
High-resolution carbonate stratigraphy of the deep-sea core MD972151 from the southwestern South China Sea shows millennial-scale variability similar to oxygen isotopic fluctuations recorded in ice cores from Greenland. In a long term of glacial-interglacial scale, carbonate contents in the interglacial time (up to 25 % by weight) were higher than that in the glacial periods (5-15 % by weight). Even for the last glacial, carbonate contents are relatively high in the interstadial events and low in the stadial horizons. This demonstrates clearly that carbonate content in the continental slope above the lysocline in the southwestern South China Sea is primarily controlled by dilution of terrigenous inputs, which in turn is due to sea-level fluctuations in... |
Tipo: Text |
Palavras-chave: South China Sea; Carbonate stratigraphy; Ice volume; Terrigenous input. |
Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35073/34557.pdf |
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Li, Chen; Jian, Zhimin; Jia, Guodong; Dang, Haowen; Wang, Jianxin. |
Marine nitrogen fixation contributes to the budget of biologically available N, thus fuels phytoplankton productivity and carbon cycle through biological pump. Modern N‐fixation rates are proved to be constrained by oceanographic condition and nutrient supply to the surface waters. However, the paleoceanographic reconstruction of N‐fixation and its regulation mechanism remain highly uncertain in many regions. Here we present records of N‐fixation changes in the South China Sea (SCS) over the past 250,000 years reconstructed by compound‐specific nitrogen isotopes of individual amino acids. The δ15N of source amino acids (δ15NSrc), reflecting the δ15N of the substrate nitrate originating from the subsurface water, is distinctly lower during interglacial... |
Tipo: Text |
Palavras-chave: Compound-specific delta N-15; Upper water structure; Bulk sedimentary delta N-15; Nitrogen fixation; Orbital time scale; South China Sea. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00509/62061/66237.pdf |
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Lee, Tq. |
This study presents the directional paleomagnetic secular variation pattern of core MD972151 taken from the southwestern South China Sea during the IMAGES III - IPHIS Cruise in 1997. A total of 281 samples taken from this; core were subjected to AF demagnetization to analyze their characteristic remanent magnetization. The results indicated a reversed event at depth of between 21.7 and 23.8 meters. It was identified as the Blake Event, and has an age interval of about 130 ka. Another short reversed event was found near the bottom of the core. This was tentatively described as an excursion that occurred at about 150-160 ka. These assignments were in very close agreement with the results of oxygen isotope analysis. Consequently, the core under study was... |
Tipo: Text |
Palavras-chave: Paleomagnetic secular variation; VGP; South China Sea; IMAGES. |
Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35074/34552.pdf |
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Chen, Yy; Chen, Mt; Fang, Ts. |
Ultrahigh resolution records of carbonate and organic carbon concentrations from core MD972148 (19 degrees 47.804'N 117 degrees 32.56'E; water depth 2830 m) provide information on glacial-interglacial as well as millennial to centennial scale variability in the production of biogenic sediments in the northern slope of the South China Sea (SCS) over the past 150,000 years. A preliminary age model of this record is estimated using a biostratigraphic datum of Globigerinoides ruber (pink) and the relationship of carbonate concentrations and partial derivative(18)O of planktonic foraminifers shown in previous SCS records. The downcore patterns in this record show that the carbonate concentration maxima correspond to interglacial times and minima correspond to... |
Tipo: Text |
Palavras-chave: Paleoceanography; Late Quaternary; Carbonate sedimentology; South China Sea. |
Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35072/34559.pdf |
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He, Juan; Zhao, Meixun; Li, Li; Wang, Hui; Wang, Pinxian. |
High-resolution molecular abundance records for several marine biomarkers during the last glacial and Holocene have been generated for core MD05-2904 (19 degrees 27.32'N, 116 degrees 15.15'E, 2066 in water depth) from the northern South China Sea. The U-37(K') SST record indicates a 4.4 degrees C cooling during the Last Glacial Maximum for this site, consistent with previous reconstructions. The contents Of C-37 alkenones, dinosterol, brassicasterol, and C-30 alkyl diols are used as productivity proxies for haptophytes, dinoflagellates, diatoms, and eustigmatophytes, respectively. These records reveal that both individual phytoplankton group and total productivity increased by several factors during the LGM compared with those for the Holocene, in response... |
Tipo: Text |
Palavras-chave: Biomarkers; Paleo-productivity; Community structure; Sea surface temperature; South China Sea. |
Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00207/31845/30258.pdf |
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Cai, Sq; Huang, Qz; Long, Xm. |
A three-dimensional baroclinic shelf sea model is employed to simulate the tidal and non-tidal residual current in the South China Sea. The four most significant constituents, M-2, S-2, K-1 and O-1, are included in the experiments with tidal effect. At most stations, the computed harmonic constants agree well with the observed ones. The circulations of the South China Sea in summer (August) and winter (December) are mainly discussed. It is shown that the barotropic tidal residual current is too weak to affect the South China Sea circulation, whilst the contribution of the baroclinic tidal residual current to the South China Sea circulation would be important in the continental shelf sea areas, especially in the Gulf of Thailand and Gulf of Tonkin. In the... |
Tipo: Text |
Palavras-chave: Marée; Courant résiduel; Modèle numérique; Mer de Chine du Sud; Tides; Tidal current; Residual current; Numerical model; South China Sea. |
Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00321/43251/42982.pdf |
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Shiau, Liang-jian; Yu, Pai-sen; Wei, Kuo-yen; Yamamoto, Masanobu; Lee, Teh-quei; Yu, Ein-fen; Fang, Tien-hsi; Chen, Min-te. |
Variations in sea surface temperature (SST), productivity, and biogenic components such as total organic carbon (TOC), carbonate, and opal contents measured from IMAGES (International Marine Global Changes Study) core MD972142 provide information about long-term paleoceanographic changes during the past similar to 870000 years in the southeastern South China Sea (SCS). MD972142 U-37(k)-SSTs varied from 25 to 29 degrees C, paralleling the glacial to interglacial changes. MD972142 biogenic components show relatively high carbonate and opal, and low TOC contents in interglacial stages, and low carbonate and opal and high TOC contents in glacial stages, and these variations appear to be sensitive to regional terrestrial sediment input and productivity. Our... |
Tipo: Text |
Palavras-chave: Total organic carbon; Carbonate; Opal; Productivity; Sea surface temperature; South China Sea; Monsoon; IMAGES. |
Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34817/33682.pdf |
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Sibuet, Jean-claude; Yeh, Yi-ching; Lee, Chao-shing. |
The beginning of seafloor spreading in the South China Sea (SCS) is now established from IODP drilling Leg 349 at 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17-22 Ma ago. Based on magnetic anomalies identifications, the end of the SCS spreading could be either 15.5, 20.5 Ma (Briais et al., 1993; Barckhausen et al., 2014) or something else. However, as post-spreading magmatic activity (~ 13-3.5 Ma) largely masks the spreading fabric in particular near the axis of the east sub-basin, published locations of... |
Tipo: Text |
Palavras-chave: South China Sea; Gravity; Magnetics; Structural and tectonic analyses; Kinematics. |
Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00316/42686/42059.pdf |
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Cai, Sq; Long, Xm; Gan, Zj. |
A new composite model, which consists of a generation model of the internal tides and a regularized long wave propagation model, is presented to study the generation and evolution of internal solitary waves in the sill strait. Internal bores in the sill strait are first simulated by the generation model. and then the internal tidal field outside of the sill region is given as input for the propagation model. Numerical experiments are carried out to Study the imposing tide, depth profile. channel width and shoaling effect, etc., on the generation and evolution of internal solitary waves. It is shown that only when the amplitude of internal tide at the forcing boundary of the propagation model is large enough that a train of internal solitary waves would be... |
Tipo: Text |
Palavras-chave: Marée interne; Modèle numérique de soliton; Mer de Chine; Internal wave; Soliton; Numerical model; South China Sea. |
Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00322/43319/42935.pdf |
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Wang, Px; Tian, J; Cheng, Xr; Liu, Cl; Xu, J. |
Carbon isotope sequences at Ocean Drilling Program Site 1143, South China Sea, reveal a long-term cyclicity of similar to500 kyr that is superimposed on the glacial cycles and is present in long delta(13)C sequences from all oceans. The Quaternary delta(13)C record is punctuated by four delta(13)C maximum events: delta(13)Cmax-I, which began in marine isotope stage (MIS) 3 around 50-60 kyr ago, delta(13)Cmax-II (MIS 13, 0.47-0.53 Ma), delta(13)Cmax-III (MIS 27-29, 0.97-1.04 Ma) and delta(13)Cmax-VI (MIS 53-57, 1.55-1.65 Ma). As the same cyclicity is also found in carbonate curves, the delta(13)Cmax events must denote major reorganization in the carbon reservoir of the global ocean. They also are associated with major changes in glacial cyclicity, such as... |
Tipo: Text |
Palavras-chave: Long-term cyclicity; Carbon isotope; South China Sea. |
Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00229/33996/32414.pdf |
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Waheed, Zarinah; Benzoni, Francesca; Van Der Meij, Sancia E. T.; Terraneo, Tullia I.; Hoeksema, Bert W.. |
Layang-Layang is a small island part of an oceanic atoll in the Spratly Islands off Sabah, Malaysia. As the reef coral fauna in this part of the South China Sea is poorly known, a survey was carried out in 2013 to study the species composition of the scleractinian coral families Fungiidae, Agariciidae and Euphylliidae. A total of 56 species was recorded. The addition of three previously reported coral species brings the total to 59, consisting of 32 Fungiidae, 22 Agariciidae, and five Euphylliidae. Of these, 32 species are new records for Layang-Layang, which include five rarely reported species, i.e., the fungiids Lithophyllon ranjithi, Podabacia sinai, Sandalolitha boucheti, and the agariciids Leptoseris kalayaanensis and L. troglodyta. The coral fauna... |
Tipo: Text |
Palavras-chave: Scleractinia; South China Sea; Malaysia; Atoll; Distribution ranges; New records; Species richness. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00585/69700/67567.pdf |
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Registros recuperados: 24 | |
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