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Time-Frequency Variations of Plio-Pleistocene Foraminiferal Isotopes: A Case Study from Southern South China Sea

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Journal of China University of Geosciences 2004年第3期15卷 283-289页

作者： TianJun WangPinxian chengxinrong LaboratoryofMarineGeology TongjiUniversityShanghai200092China

The continuous wavelet transform (CWT) analysis reveals the instantaneous variability of the foraminiferal δ 18O and δ 13C of Site 1143 for the past 5 Ma at the eccentricity, obliquity and precession bands. The cross CWT analysis further demonstrates nonstationary phases of the benthic -δ 18O relative to ETP at the three primary Milankovitch bands in the last 5 Ma. The instantaneous phases between benthic -δ 18O and δ 13C at the precession band display a prominent 128 ka period, probably the cyclicity of the nonstationary climate close to the eccentricity. To explain these nonstationary phases, it is desirable to introduce a nonlinear response model to the global climate system, in which the output has a prominent cycle around 100 ka to match the 128 ka cycle of the instantaneous phase of the δ 13C and -δ 18O on the precession band.

关键词： wavelet analysis foraminiferal isotopes South China Sea.

Thirty million year deep-sea records in the South China Sea

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Chinese Science Bulletin 2003年第23期48卷 2524-2535页

作者： WANGPinxian ZHAOQuanhong JIANZhimin chengxinrong HUANGWei TIANJun WANGJiliang LIQianyu LIBaohua SUXin KeyLaboratoryofMarineGeology MinistryofEducationTongjiUniversityShanghai200092China NanjingInstituteofGeologyandPaleontology ChineseAcademyofSciencesNanjing210008China GeoscienceUniversityofChina Beijing100083China

In the spring of 1999 the Ocean Drilling Pro-gram (ODP) Leg 184 Shipboard Party cored 17 holes at 6 deep water sites in the northern and southern parts of the South China Sea (SCS). Chinese scientists actively partici-pated in the entire process of this first deep-sea drilling leg off China, from proposal to post-cruise studies. More than 30 categories of analyses have been conducted post-cruise in various Chinese laboratories on a large number of core sam-ples, and the total number of analyses exceeded 60 thousand. The major scientific achievements of the Leg 184 studies are briefly reported in three successive papers, with the first one presented here dealing with deep-sea stratigraphy and evolu-tion of climate cycles. This ODP leg has established the best deep-sea stratigraphic sequences in the Western Pacific: the 23-Ma isotope sequence from the Dong-Sha area is unique worldwide because of its continuity; the last 5-Ma sequence from the Nansha area represents one of the best 4 ODP sites worldwide with the highest time-resolution for that time in-terval, and the sequences of physical properties enable a de-cadal-scale time resolution. All these together have provided for the first time high-quality marine records for paleoenvi-ronmental studies in the Asian-Pacific region. This new set of stratigraphic records has revealed changes in climate cyclic-ity over the last 20 Ma with the fluctuating power of the 100 ka, 400 ka, 2000 ka eccentricity cycles, indicating the evolv-ing response of the climate system to orbital forcing along with the growth of the Antarctic and Northern Hemisphere ice sheets.

关键词：南中国海海洋钻探工程深海沉积 ODP SCS 轨道循环

Carbon isotopic record of foraminifers in surface sediments from the South China Sea and its significance

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Chinese Science Bulletin 2005年第2期50卷 162-166页

作者： chengxinrong WANGPinxian HUANGBaoqi LIUChuanlian JIANZhimin ZHAOQuanhong LIJianru TIANJun XUJian LaboratoryofMarineGeology TongjiUniversityShanghai200092China

The study is based on stable carbon isotopic measurements of 112 foraminiferal samples from surface sediments at 40 sites in the South China Sea (SCS). δ 13C of foraminifers and ?δ C between planktonic and benthic 13 foraminiferal species exhibit a low value area at the north- eastern and southern ends of the SCS. It is correlated with the nutrient distributional pattern in the SCS and circumja- cent area, the influence of the northeastern and southwestern monsoons on water flow and water chemistry in the SCS. The monsoons have not only brought nutrients to the upper part of the sea but also disturbed water and decreased dif- ference between the surface and bottom water. Its influence is most obvious at both ends, which resulted in the low value areas in δ 13C and ?δ 13C at the ends. The distributional pat- tern of the stable carbon isotope in the SCS is a reflection of the East Asian monsoons.

关键词：碳同位素标记有孔虫表面沉积物南海季候风营养分配