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| Setiawan, Riza Yuliratno; Mohtadi, Mahyar; Southon, John; Groeneveld, Jeroen; Steinke, Stephan; Hebbeln, Dierk. |
| The advection of relatively fresh Java Sea water through the Sunda Strait is presently responsible for the low-salinity tongue in the eastern tropical Indian Ocean with salinities as low as 32. The evolution of the hydrologic conditions in the eastern tropical Indian Ocean since the last glacial period, when the Sunda shelf was exposed and any advection via the Sunda Strait was cutoff, and the degree to which these conditions were affected by the Sunda Strait opening are not known. Here we have analyzed two sediment cores (GeoB 10042-1 and GeoB 10043-3) collected from the eastern tropical Indian Ocean off the Sunda Strait that cover the past similar to 40,000years. We investigate the magnitude of terrigenous supply, sea surface temperature (SST), and... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Sunda Strait; Seawater oxygen isotopes; Java Sea; Sea surface temperatures; Terrigenous supply. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00496/60729/65238.pdf |
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| Steinke, Stephan; Mohtadi, Mahyar; Groeneveld, Jeroen; Lin, Li-chuan; Lowemark, Ludvig; Chen, Min-te; Rendle-buehring, Rebecca. |
| Upper water column dynamics in the southern South China Sea were reconstructed in order to track changes in the activity of the East Asian winter monsoon (EAWM) since the Last Glacial Maximum. We used the difference in the stable oxygen isotopes (Delta delta O-18) and Mg/Ca-based temperatures (Delta T) of surface-dwelling (G. ruber) and thermocline-dwelling (P. obliquiloculata) planktonic foraminifera and the temperature difference between alkenone- and P. obliquiloculata Mg/Ca-based temperatures to estimate the upper ocean thermal gradient at International Marine Past Global Change Study (IMAGES) core MD01-2390. Estimates of the upper ocean thermal gradient were used to reconstruct mixed layer dynamics. We find that our Delta delta O-18 estimates are... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34204/32845.pdf |
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| Ho, Sze Ling; Mollenhauer, Gesine; Lamy, Frank; Martinez-garcia, Alfredo; Mohtadi, Mahyar; Gersonde, Rainer; Hebbeln, Dierk; Nunez-ricardo, Samuel; Rosell-mele, Antoni; Tiedemann, Ralf. |
| In spite of the important role played by the Southern Ocean in global climate, the few existing paleoceanographic records in the east Pacific sector do not extend beyond one glacial-interglacial cycle, hindering circumpolar comparison of past sea surface temperature (SST) evolution in the Southern Ocean. Here we present three alkenone-based Pleistocene SST records from the subantarctic and subtropical Pacific. We use a regional core top calibration data set to constrain the choice of calibrations for paleo SST estimation. Our core top data confirm that the alkenone-based U-37(K) and U-37(K') values correlate linearly with the SST, in a similar fashion as the most commonly used laboratory culture-based calibrations even at low temperatures (down to similar... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37610/36990.pdf |
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| Gibbons, Fern T.; Oppo, Delia W.; Mohtadi, Mahyar; Rosenthal, Yair; Cheng, Jun; Liu, Zhengyu; Linsley, Braddock K.. |
| Evidence from geologic archives suggests that there were large changes in the tropical hydrologic cycle associated with the two prominent northern hemisphere deglacial cooling events, Heinrich Stadial 1 (HS1; similar to 19 to 15 kyr BP; kyr BP = 1000 yr before present) and the Younger Dryas (similar to 12.9 to 11.7 kyr BP). These hydrologic shifts have been alternatively attributed to high and low latitude origin. Here, we present a new record of hydrologic variability based on planktic foraminifera-derived delta O-18 of seawater (delta O-18(sw)) estimates from a sediment core from the tropical Eastern Indian Ocean, and using 12 additional delta O-18(sw) records, construct a single record of the dominant mode of tropical Eastern Equatorial Pacific and... |
| Tipo: Text |
Palavras-chave: Indo-Pacific; Eastern Equatorial Pacific; Delta O-18 of seawater; Deglaciation; Heat transport. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00496/60737/65207.pdf |
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