Development of the East Asian monsoon and Northern Hemisphere glaciation; oxygen isotope records from the South China Sea

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doi: 10.1016/j.quascirev.2004.02.013
Author(s): Tian Jun; Wang Pinxian; Cheng Xinrong
Author Affiliation(s): Primary:
Tongji University, Laboratory of Marine Geology, Shanghai, China
Chinese Academy of Sciences, China
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, 23(18-19), p.2007-2016. Publisher: Pergamon, Oxford, United Kingdom. ISSN: 0277-3791
Note: In English. 43 refs.; illus., incl. geol. sketch map
Summary: Oxygen isotope records of the surface-dwelling foraminifer Globigerinoides ruber from ODP Site 1143 in the southern South China Sea (SCS) are presented for the last 5 Ma. The G. ruber δ18O of Site 1143 for the past 500 ka is lighter by 0.5-1.0 per mil in interglacial, and by 0.1-0.5 per mil in glacial periods, than the Site 806B record from the Ontong Java Plateau. We infer the light glacial/interglacial G. ruber δ18O at Site 1143, compared with the open western Pacific, to have been caused by stronger monsoon-induced precipitation over the SCS. While glacial/interglacial planktonic δ18O values remained stable over the 3.3-2.5 Ma period, the benthic Cibicidoides wuellerstorfi δ18O gradually became positive, leading to an obvious slope in their δ18O difference (Δδ18Ob-p). The stable glacial/interglacial G. ruber δ18O over this period is probably caused by the decrease of sea surface salinity, which counteracted the effects of global ice volume and sea surface temperature on the G. ruber δ18O. We interpret that the intensification of the East Asian monsoon winds coupled with the northern hemisphere glaciation 3.3-2.5 Ma ago likely brought frequent and strong precipitation over the SCS and/or caused large-scale intrusions of Borneo alongshore low-salinity waters to the southern SCS, which greatly freshened the SCS and decreased its salinity. After 2.5 Ma, especially in the Quaternary period, the planktonic and benthic δ18O show similar variations over glacial/interglacial cycles in responding to the waxing and waning of the northern hemisphere continental ice sheet, and their relatively stable δ18O difference (Δδ18Ob-p) indicates a period of steady fluctuations of the East Asian monsoon winds. The more positive values of Δδ18Ob-p probably suggest stronger East Asian winter monsoon during Quaternary glacials whereas the more negative values of Δδ18Ob-p may imply stronger East Asian summer monsoon during Quaternary interglacials. Abstract Copyright (2004) Elsevier, B.V.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Benthic environment; Cenozoic; Cycles; Eastern Asia; Glaciation; Holocene; Interglacial environment; Isotope ratios; Isotopes; Leg 184; Monsoons; North Pacific; Northern Hemisphere; Northwest Pacific; O-18; O-18/O-16; ODP Site 1143; Ocean Drilling Program; Oxygen; Pacific Ocean; Paleoclimatology; Paleotemperature; Plankton; Quaternary; Reconstruction; South China Sea; Stable isotopes; West Pacific
Coordinates: N092143 N092143 E1131707 E1131707
Record ID: 2005071583
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands