| 南海北部陆坡近四万年的高分辨率古海洋学记录 |
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| 引用本文： | 王律江,M. Sarnthein.南海北部陆坡近四万年的高分辨率古海洋学记录[J].第四纪研究,1999,19(1):27-31. |
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| 作者姓名： | 王律江 M. Sarnthein |
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| 作者单位： | 同济大学海洋地质开放实验室!上海，200092，基尔大学地球科学研究所!德国 |
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| 基金项目： | 国家自然科学基金!49576286 |
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| 摘 要： | 南海北部陆坡在东沙群岛东南水深1727m处所采的17940柱状样,提供了迄今所知南海最高沉积速率的次深海沉积,全新统厚达6．5m。全柱13.30m的沉积物记录了近4万年来南海古海洋变迁的历史。通过间距1～2cm的高密度采样进行氧同位素分析及其它分析,结果揭示了全新世夏季风百年等级的变化周期和冰期时千年等级的准周期性气候波动。
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| 关 键 词： | 南海 晚第四纪 古海洋学 高分辨率地层学 |
| 收稿时间： | 1998-08-14 |
| 修稿时间： | 1998-10-25 |
HIGH-RESOLUTION PALEOCEANOGRAPHIC RECORDS DURING THE LAST 40 000 YEARS FROM THE NORTHERN SLOPE OF THE SOUTH CHINA SEA |
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| Wang Lujiang, M.Sarnthein.HIGH-RESOLUTION PALEOCEANOGRAPHIC RECORDS DURING THE LAST 40 000 YEARS FROM THE NORTHERN SLOPE OF THE SOUTH CHINA SEA[J].Quaternary Sciences,1999,19(1):27-31. |
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| Authors: | Wang Lujiang MSarnthein |
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| Institution: | 1. Laboratory of Marine Geology, Tongji University, Shanghai 200092;
2. Institut fur Geowissenschaften, Kiel Universitat, Germany |
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| Abstract: | A high sedimentation rate record of hemipelagic deposits was found in Core 17940 taken from the northern slope of the South China Sea (20°07' N, 1 17°23' E, w.d. 1 727m), about 400 kin southeast of Hong Kong, during the R/V SONNE cruise 95 in 1994. Based on magnetic susceptibility and stable isotope data, a composite-depth (c. d.) section was spliced. A total of 40 samples of Planktonic foraminifers Globigerinoides ruber or G. sacculifer have been measured for AMS 14C dating, and a high-resolution downcore sequence of oxygen and carbon isotopes of G. ruber s.s. (white) was obtained from samples in 1-2 cm interval.Judging from the results of isotopic analyses, the Holocene of the section reaches 6.5m in thickness, displaying the highest hemipelagic sedimentation rate in the South China Sea (40- 85cm/ 103a). Accordingly, a 1cm-sampling provides a bine resolution of less than 20 years for the Holocene. The glacial section displays a lower sedimentation of about 19 cm/ 103a in average. The Younger Dryas is clearly recorded as a major δ 18O increase by 0.7‰ and the total core length 13.30m has recorded a history of ca. 41 000 years.The range of frequent fluctuations in δ 18O reaches 0.7‰ or even 1.0‰ in the Holocene, reflecting the changes in precipitation driven by summer-monsoon implying subndllennial Periods of 775 years and 102 / 84 years in the East Asian monsoon regime. The δ 18O minima recorded in the glacial section obviously correspond to the bosgaard/Oeschger warm events recorded in the GISP2 ice core.Although the present paper is a brief report of the high-resolution stratigraphy and oxygen isotope records of core 17940, without detailed discussions on monsoon variations based on its siliciclastic grain-size, foraminiferal and pollen analyses, it is already clear that the hemipelagic depositS from the northern South China Sea are extremely promising in providing high-resolution records of East Asian Monsoons and environmental changes in the Western Pacific region. |
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| Keywords: | South China Sea late Quaternary paleoceanography high-resolution stratigraphy |
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