國際海洋古全球變遷研究總計畫─利用多種類浮游有孔蟲氧碳同位素比值重建過去16萬年南海溫躍層之水文結構
Other Title
Sea-surface hydrographic variations during the past 165,000 years in the
southeastern South China Sea (near Palawan Island)
southeastern South China Sea (near Palawan Island)
Date Issued
2004
Date
2004
Author(s)
DOI
922116M002008
Abstract
Using Mg/Ca ratios of planktonic foraminifer Globigerinoides sacculifer and alkenone
unsaturation index of bulk sediments from the deep-sea core MD972142, we reconstructed
sea-surface paleotemeratures of the past 165 thousand years for the southeastern South China
Sea near the Palawan Island. The paleo-SSTs fluctuated between ~24 o C and 29 o C through the
past two glacial-interglacial cycles with the coldest SSTs of ~24 o C at the last glacial
maximum. The SSTs during the late Holocene are comparable to the peak values of the
marine oxygen isotope stage 5.
To examine the salinity/hydrographic variation, the effects of temperature and
ice-volume were subtracted from the δ 18 O values of planktonic foraminifer Globigerinoides
sacculifer. The resultant residual δ 18 O profiles indicate that the surface oceans have been
fresher than today’s for most of the time during the past 165 thousand years. In general,
during the low sea-level periods in glacial stages, the corrected δ 18 O values tend to deviate
from the current value, signifying various degrees of freshening. Contrarily, when the
sea-levels were high, the surface waters tend to be as salty as it is today. Nevertheless, at
millennial scale, the surface waters were more stratified during the interstadial than in the
stadial intervals due to stronger fresh-water input and higher surface temperature.
Subjects
South China Sea
SSTs
Hydrograph
Paleotemperature
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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