國際海洋古全球變遷研究─(總計畫及子計畫一)過去三十萬年以來的南海及西菲律賓海的古季風與古海洋變遷(I)
Other Title
Variability of Paleomonsoon and paleoceanography of the South China
Sea and West Philippine Sea in the last 300Kyrs (I)
Sea and West Philippine Sea in the last 300Kyrs (I)
Date Issued
1998
Date
1998
Author(s)
黃奇瑜
DOI
872611M002004
Abstract
High resolution records of an IMAGES
deep-sea core (MD 972151; 8 o 43.73’N, 109
o 52.17’E at water depth of 1,598 m) from the
semi-closed South China Sea (SCS) reveal a
millennial-scale paleoclimatic fluctuations
with D-O cycles and Heinrich events
reported from the high latitude regions in the
Northern Hemisphere. In a long-term
Milankovitch orbital time scale, carbonate
contents and alkenone stratigraphy are
parallel to planktic oxygen isotope
stratigraphy. In a short-term millennial
scale, both carbonate content and U k’
37 SST
are rapidly fluctuated in a high frequency like
Greenland ice cores. In interglacial and the
warm interstadial events in the last glacial
time, U k’
37 SST (27-28.5 ℃ in Stages 1 and 5;
25.5-26.5 ℃ in interstadial events) and
carbonate contents (20-25 % in Stages 1 and
5; 10-15 % in interstadial events) are
relatively high. In contrast, in the last
glaciation (Stages 2-3-4), U k’
37 SST and
carbonate contents are relatively low,
especially in the stadial events (SST: 24-24.5 ℃, CaCO3 : 3-5 %). Both carbonate contents
and U k’
37 SST in the SCS are primarily
controlled by ice volume fluctuations and
paleomonsoon conditions. Increase of ice
volume in the last glacial time enhanced the
atmospheric Siberian high pressure to
intensify winter monsoon, thus decreased
U k’
37 SST in the SCS. Meantime, increase of
ice volume also resulted in a low standing of
sea level, thus exposed the Sunda Shelf to
contribute much continental materials to
dilute carbonate contents in the SCS marine
sediments.
The South China Sea paleoceanography is
also correlated with paleomonsoon records in
the Chinese Loess Plateau, the lower U k’
37
SST (the stronger winter paleomonsoon) in
the SCS the coarser grain sizes in the
Chinese loess sequences. Both Milankovitch
orbital forcing and the rapid earth internal
interactions of ice-atmosphere-ocean climate
systems are responsible for millennial-scale
paleoclimatic tele-connections among
Greenland ice cores, Chinese loess sequences
and South China Sea deep-sea core.
Subjects
South China Sea
millennial-scale
SDGs
Publisher
臺北市：國立臺灣大學地質科學系暨研究所
Type
report
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