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Xiong, Zhifang; Li, Tiegang; Algeo, Thomas; Doering, Kristin; Frank, Martin; Brzezinski, Mark A.; Chang, Fengming; Opfergelt, Sophie; Crosta, Xavier; Jiang, Fuqing; Wan, Shiming; Zhai, Bin. |
The cause of massive blooms of Ethmodiscus rex laminated diatom mats (LDMs) in the eastern Philippine Sea (EPS) during the Last Glacial Maximum (LGM) remains uncertain. In order to better understand the mechanism of formation of E. rex LDMs from the perspective of dissolved silicon (DSi) utilization, we determined the silicon isotopic composition of single E. rex diatom frustules (delta Si-30(E.rex)) from two sediment cores in the Parece Vela Basin of the EPS. In the study cores, delta Si-30(E.rex) varies from -1.23 parts per thousand to -0.83 parts per thousand (average -1.04 parts per thousand), a range that is atypical of marine diatom delta Si-30 and that corresponds to the lower limit of reported diatom delta Si-30 values of any age. A binary mixing... |
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Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00496/60732/65231.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, Zhaojie; Colin, Christophe; Douville, Eric; Meynadier, Laure; Duchamp-alphonse, Stephanie; Sepulcre, Sophie; Wan, Shiming; Song, Lina; Wu, Qiong; Xu, Zhaokai; Bassinot, Frank. |
The dissolved Yttrium (Y) and Rare Earth Element (REE) concentrations of seawater samples collected along a north-south hydrological transect within the Bay of Bengal (BoB) have been analyzed to estimate contributions of the Ganges and Brahmaputra (G-B) river inputs to the dissolved REE distribution of the Northern Indian Ocean. Surface water masses of the BoB are characterized by Y/Ho ratios (84) intermediate between the G-B river suspended sediment (41) and water mass from the South Indian Ocean (93). Co-variation of MREE (Middle REE, Sm) and LREE (Light REE, La) concentrations suggests that the dissolved REEs in surface waters (upper 100 m depth) of the BoB (Sm/La = 0.21) appear to derive mainly from the freshwater discharge of the G-B river system. In... |
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Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00377/48845/49277.pdf |
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Zhao, Debo; Wan, Shiming; Toucanne, Samuel; Clift, Peter D.; Tada, Ryuji; Revillon, Sidonie; Kubota, Yoshimi; Zheng, Xufeng; Yu, Zhaojie; Huang, Jie; Jiang, Hanchao; Xu, Zhaokai; Shi, Xuefa; Li, Anchun. |
High-resolution multi-proxy records, including clay minerals and Sr-Nd-Pb isotopes of the clay-sized silicate fraction of sediments from IODP Site U1429 in the northern Okinawa Trough, provide reliable evidence for distinct control mechanism on fine-grained sediments input from the Yellow River and the southern Japanese Islands to the northern Okinawa Trough since 34 ka BP. Provenance analysis indicates that the sediments were mainly derived from the Yellow River and the island of Kyushu. Since the last glacial, clay-sized sediments transported from the Yellow River to the study site were strongly influenced by sea-level fluctuation. During low sea-level stage (∼34‒14 ka BP), the paleo-Yellow River mouth was positioned closer to the northern Okinawa... |
Tipo: Text |
Palavras-chave: Okinawa Trough; Clay-sized sediments; Yellow River; Kyushu Island; Sea-level change; Kuroshio Current; Tsushima Warm Current. |
Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00393/50413/51129.pdf |
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Tada, Ryuji; Irino, Tomohisa; Ikehara, Ken; Karasuda, Akinori; Sugisaki, Saiko; Xuan, Chuang; Sagawa, Takuya; Itaki, Takuya; Kubota, Yoshimi; Lu, Song; Seki, Arisa; Murray, Richard W.; Alvarez-zarikian, Carlos; Anderson, William T., Jr.; Bassetti, Maria-angela; Brace, Bobbi J.; Clemens, Steven C.; Da Costa Gurgel, Marcio H.; Dickens, Gerald R.; Dunlea, Ann G.; Gallagher, Stephen J; Giosan, Liviu; Henderson, Andrew C. G.; Holbourn, Ann E.; Kinsley, Christopher W.; Lee, Gwang Soo; Lee, Kyung Eun; Lofi, Johanna; Lopes, Christina I. C. D.; Saavedra-pellitero, Mariem; Peterson, Larry C.; Singh, Raj K.; Toucanne, Samuel; Wan, Shiming; Zheng, Hongbo; Ziegler, Martin. |
The Quaternary hemipelagic sediments of the Japan Sea are characterized by centimeter-to decimeter-scale alternation of dark and light clay to silty clay, which are bio-siliceous and/or bio-calcareous to a various degree. Each of the dark and light layers are considered as deposited synchronously throughout the deeper (> 500 m) part of the sea. However, attempts for correlation and age estimation of individual layers are limited to the upper few tens of meters. In addition, the exact timing of the depositional onset of these dark and light layers and its synchronicity throughout the deeper part of the sea have not been explored previously, although the onset timing was roughly estimated as similar to 1.5 Ma based on the result of Ocean Drilling Program... |
Tipo: Text |
Palavras-chave: Quaternary sediments; Japan Sea; Inter-site correlation; High-resolution age model; IODP; Expedition 346; U1424; U1425; U1426; U1430. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54817/56292.pdf |
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Yu, Zhaojie; Colin, Christophe; Bassinot, Franck; Wan, Shiming; Bayon, Germain. |
Chemical weathering of silicate rocks on continents is thought to have played an important role in the evolution of past atmospheric carbon dioxide over geologic timescales. However, the detailed links between continental weathering and climate change over shorter timescales, and their potential impact on sediment records deposited in the ocean, remain poorly understood. Here, we present clay mineralogy and strontium‐neodymium isotopic data for marine sediment records from the Northern Indian Ocean, with the aim of investigating the weathering response of large Himalayan river basins to orbital and millennial climate forcing. We show that past glaciated episodes of the late Quaternary corresponded to periods of increased physical erosion, associated with... |
Tipo: Text |
Palavras-chave: Climate change< /AUTHOR_KEYWORD> Continental weathering< /AUTHOR_KEYWORD> Highlands and floodplains< /AUTHOR_KEYWORD> Carbon cycle< /AUTHOR_KEYWORD> Himalaya< /AUTHOR_KEYWORD>. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00632/74434/74154.pdf |
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Wan, Shiming; Toucanne, Samuel; Clift, Peter D.; Zhao, Debo; Bayon, Germain; Yu, Zhaojie; Cai, Guanqiang; Yin, Xuebo; Revillon, Sidonie; Wang, Dawei; Li, Anchun; Li, Tiegang. |
During the Holocene there has been a gradual increase in the influence of humans on Earth systems. High-resolution sedimentary records can help us to assess how erosion and weathering have evolved in response to recent climatic and anthropogenic disturbances. Here we present data from a high-resolution (∼75 cm/k.y.) sedimentary archive from the South China Sea. Provenance data indicate that the sediment was derived from the Red River, and can be used to reconstruct the erosion and/or weathering history in this river basin. Accelerator mass spectrometry 14C dating provides direct age control and reveals coherent variations in clay mineralogy, geochemistry, and terrigenous flux, indicative of strong chemical weathering and physical erosion during the... |
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Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00266/37754/37175.pdf |
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Zheng, Xufeng; Li, Anchun; Wan, Shiming; Jiang, Fuqing; Kao, Shuh Ji; Johnson, Cody. |
Deep-sea fan sediments provide an excellent geological archive for paleoenvironment reconstruction. Grain size, clay mineral and elemental (Ti, Fe, Ca) compositions were measured for a core retrieved from a submarine fan in the Okinawa Trough. Varimax-rotated Principal Component Analysis (V-PCA) on time-evolution of grain size spectrum reveals that, since the Holocene, sediment was transported mainly by the benthic nepheloid layer (33%) and upper layers (33%) which is driven by the East Asian winter monsoon (EAWM). The intensification of the Kuroshio Current during the Holocene, masks the fluvial signal of the summer monsoon and obstructs clay minerals derived from the Yellow River, a major contributor prior to 12 ka BP. A new grain size index (GSI), which... |
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Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40118/39283.pdf |
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