Late Quaternary Surface Circulation Variability in the South China Sea

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Project title

Code/計畫編號

NSC88-2611-M019-008-IM

Translated Name/計畫中文名

國際海洋古全球變遷研究(IMAGES)---總計畫及子計畫II：南海晚第四紀之表層環流變化

Project Coordinator/計畫主持人

Min-Te Chen

Funding Organization/主管機關

National Science and Technology Council

Co-Investigator(s)/共同執行人

余英芬
方天熹
黃奇瑜
魏國彥

Department/Unit

Institute of Earth Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=453125

Year

1999

Start date/計畫起

01-08-1998

Expected Completion/計畫迄

01-07-1999

Co-Investigator(s)

Tien-Hsi Fang

Bugetid/研究經費

2691千元

ResearchField/研究領域

海洋科學

Hemipelagic sediments accumulated on the northern part of the south China Sea (SCS) basin near the Pearl River provide high-resolution records for interpreting millennial to centennial scale paleoclimate changes of the western Pacific Ocean. Here we present results of stratigraphy and paleoceanography for the last deglaciation (~25,000 yrs) from a giant piston core taken from this region during the IMAGES III cruise of year 1997 (MD972148: 19o7.804'N, 117o2.56'E, 2830m). High-resolution, multiple proxy data of the time interval were generated for this core, including analyses of planktic foraminifer oxygen stable isotopes, faunal assemblage sea-surface temperature (SST), Uk'37 SST, and biogenic sedimentary components of organic carbon and carbonate. The completeness of the data set enables us to better interpret the sequence of high-frequency paleoclimate signals over millennial-centennial scales in this record since the last glacial maximum (LGM). A planktic foraminifer oxygen isotope curve (G. sacculifer) indicates a ~1.6o change of the Holocene-LGM period, and contains a series of the structure of deglaciation changes such as the Younger Dryas cooling and the Bolling/Allerod warming events, which are analogous with those found in the GISP2 ice core and other North Atlantic core records. The same structure of the deglaciation changes can be also found in planktic foraminifer fauna and Uk'37 SST estimates. When subtracting the ice volume and temperature effects from the MD972148 d18O curve, our data imply sea surface salinity changes in the northern part of the SCS since the LGM. The abrupt SST changes in the deglaciation share the same structure with climate changes observed from GISP2 ice d18O data, indicating a linkage between the high-latitude Northern Hemisphere and tropical ocean climate. During the two most rapid warming transitions in 11,500 and 14,500 yrs B.P., the MD972148 SST clearly shows early, and much slower rates of warming than the d18O of the same core, and possibly also the temperature of the GISP2 ice core, implying that other mechanisms linking with Southern Hemisphere climate drive the SCS ocean variability.

Keyword(s)

表層環流
古海洋
古氣候
晚第四紀
南中國海
Surface circulation
Paleoceanography
Paleoclimate
Late Quaternary
South China Sea (SCS)

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Late Quaternary Surface Circulation Variability in the South China Sea

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