Palaeovegetation variation in response to the late Oligocene-early Miocene East Asian summer monsoon in the Ying-Qiong Basin, South China Sea

AbstractChanges in paleoenvironments over the last 17,500 yr have been documented by a high-resolution clay mineralogy and grain–size records of Core KNG5 from the northern slope of the South China Sea. Our results indicate that clay minerals are mainly from the Pearl River from 17,500 to 12,500 cal yr BP, and the South China Sea modern current system began to form since 12,500 cal yr BP, as a result, Taiwan turns to be the major contributor of clay minerals after 12,500 cal yr BP. Two grain-size populations with high variability through time were identified in the 13–28 μm and 1–2.2 μm grain-size intervals. The 1–2.2 μm grain-size population are mainly controlled by provenance supply and current transport. The 13–28 μm grain-size fraction could be controlled mainly by the sea-level change. The 1–2.2 μm grain-size population record demonstrates that East Asian Summer Monsoon intensity generally follows changes in insolation and that the response is similar for a large area of China and other northern low-latitude records, implying the globality of the monsoon evolution since Holocene. The anomalous environmental conditions in the northern South China Sea may imply intensified ENSO activity during the late Holocene.

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Late Quaternary Upwelling Intensity and East Asian Monsoon Forcing in the South China Sea

Quaternary Research ◽

10.1006/qres.2001.2231 ◽

2001 ◽

Vol 55 (3) ◽

pp. 363-370 ◽

Cited By ~ 111

Author(s):

Zhimin Jian ◽

Baoqi Huang ◽

Wolfgang Kuhnt ◽

Hui-Ling Lin

Keyword(s):

South China Sea ◽

Summer Monsoon ◽

South China ◽

East Asian Summer Monsoon ◽

Asian Summer Monsoon ◽

East Asian ◽

Winter Monsoon ◽

The South China Sea ◽

Asian Summer ◽

Mis 5

AbstractForaminifera from two cores off eastern Vietnam and the northwestern Philippines, where modern summer and winter monsoon-driven upwelling occurs in the South China Sea, respectively, were analyzed to evaluate the changes in paleoproductivity and upper water structure over the last 220,000 yr. We observed enhanced organic carbon flux and a shoaled thermocline when upwelling intensified off eastern Vietnam during interglacial ages and off the northwestern Philippines during glacial ages. This indicates that the East Asian summer monsoon increased while the winter monsoon decreased during interglacial ages. Particularly, the upwelling reached a maximum off eastern Vietnam during late marine isotopic stage (MIS) 5 and off the northwestern Philippines during MIS 2, implying that the summer monsoon decreased gradually since MIS 5 while the winter monsoon displayed an opposite trend. The variations in upwelling proxies exhibit a distinct cyclicity with frequencies near 41,000 yr and 23,000 yr off eastern Vietnam, in contrast to a strong frequency peak near 100,000 yr off the northwestern Philippines. We suggest that the East Asian summer monsoon has been forced by changes in solar insolation associated with precession and obliquity, while ice-volume forcing is probably a primary factor in determining the strength and timing of the East Asian winter monsoon but with less important insolation forcing.

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