Reconstructing the southern South China Sea upper water column structure since the Last Glacial Maximum: Implications for the East Asian winter monsoon development
| Type | Article | ||||||||||||
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| Date | 2010-06 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Steinke Stephan1, 5, Mohtadi Mahyar1, Groeneveld Jeroen3, Lin Li-Chuan2, Lowemark Ludvig4, Chen Min-Te2, Rendle-Buehring Rebecca1 | ||||||||||||
| Affiliation(s) | 1 : Univ Bremen, MARUM Zentrum Marine Umweltwissensch, D-28334 Bremen, Germany. 2 : Natl Taiwan Ocean Univ, Inst Appl Geosci, Chilung 20224, Taiwan. 3 : Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany. 4 : Stockholm Univ, Dept Geol & Geochem, SE-10691 Stockholm, Sweden. 5 : Tongji Univ, State Key Lab Marine Geol, Shanghai 200092, Peoples R China. |
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| Source | Paleoceanography (0883-8305) (Amer Geophysical Union), 2010-06 , Vol. 25 , N. 2 / PA2219 , P. 1-15 | ||||||||||||
| DOI | 10.1029/2009PA001850 | ||||||||||||
| WOS© Times Cited | 70 | ||||||||||||
| Abstract | 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 biased by changes in salinity and, thus, do not display a true upper ocean thermal gradient. The Delta T of G. ruber and P. obliquiloculata as well as the alkenone- and P. obliquiloculata suggest increased surface water mixing during the late glacial, likely due to enhanced EAWM winds. Surface water mixing was weaker during the late Holocene, indicating a weaker influence of winter monsoon winds. The weakest winter monsoon activity occurred between 6.5 ka and 2.5 ka. Inferred EAWM changes since the Last Glacial Maximum coincide with EAWM changes as recorded in Chinese loess sediments. We find that the intensity of the EAWM and the East Asian summer monsoon show an inverse behavior during the last glacial and deglaciation but covaried during the middle to late Holocene. | ||||||||||||
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