PALEOCEANOGRAPHIC VARIATIONS OF THE WESTERN PACIFIC WARM POOL DURING THE MIDDLE PLEISTOCENE CLIMATE TRANSITION
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摘要: 通过对大洋钻探(ODP)第130航次807站A孔上部约25 m样品中所含浮游有孔虫的定量统计和鉴定,结合转换函数及稳定同位素分析,揭示了第四纪近1.6 Ma以来冰期旋回中赤道西太平洋的表层海水温度和温跃层深度的变化,为研究西太平洋暖池的变动提供了重要依据。研究表明,西太平洋暖池冬季表层海水温度在第四纪的冰期旋回中变化幅度超过了5℃,而温跃层深度自1.6 Ma以来有所变浅,进一步论证了西太平洋暖池的不稳定性。通过对暖池区和南海及赤道东太平洋的比较,发现南海南部和暖池的海水在第四纪具有较好的连通性,而南海北部则受季风控制影响较大;同时,赤道东、西太平洋及南海,自1.6 Ma以来温跃层深度都有不同程度的变浅。研究中发现中更新世过渡期(MPT)在许多古海洋学指标中都是一条重要的分界线,以此为界,对0~0.9和0.9~1.6 Ma两个时间段的暖池冬季表层海水温度、表层与次表层种浮游有孔虫氧同位素差值与地球轨道参数ETP分别作交叉频谱分析,结果显示暖池在响应全球气候转型的同时也表现出了低纬特有的热带气候变化的特征。Abstract: The quantitative census of planktonic foraminifera from the upper 25 m of ODP 130 Site 807A, combined with the paleotemperature data estimated by using faunal transfer function and the oxygen isotopic record, reveal the periodical changes of sea surface temperature (SST) and thermocline in the Western Pacific Warm Pool (WPWP) during the last 1.6 Ma. Our results indicate that winter SST varied over~5℃ in the glacial-interglacial cycles and the depth of thermocline (DOT) has shoaled gradually since 1.6 MaBP. Compared with the South China Sea (SCS) and the Eastern Equatorial Pacific SSTs and DOT changes, the sea surface water of the WPWP more closely connected with the southern SCS, while the northern SCS seemed to be mainly controlled by the Asian winter monsoon. Meanwhile, the DOT of the SCS and Western and Eastern Pacific became shallower on different scales for the past 1.6 Ma. It is found that the Middle Pleistocene Climate Transition (MPT) was probably the critical boundary for many paleoceanographic changes. Taking the MPT as a time boundary, a cross-spectral analysis was made between the winter SST,Δδ18O P.obliquiloculata-G.ruber and the Earth Orbital Parameter ETP for two time slices of 0~0.9 and 0.9~1.6 Ma respectively. This result shows that the paleoceanographic changes in the WPWP followed the global climate periodicity transition from 41 to 100 ka and displayed a typical tropical forcing character.
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[1] Yan X H,Hou C R,Zheng Q,et al. Temperature and size varibilities of the Western Pacific Warm Pool[J]. Science,1992,58:1643-1645.
[2] Webster P J,Magana V O,Palmer T N,et al. Monsoon:processes,predictability and the prospects for prediction[J]. Journal of Geophysical Research,1998,103(C7):14451-14510.
[3] Cane M A. A role for the tropical Pacific[J]. Science,1998,282:59-61.
[4] Sun X J,Luo Y L,Huang F,et al. Deep-sea pollen from the South China Sea:Pleistocene indicators of East Asian monsoon[J]. Marine Geology,2003,201:97-118.
[5] Thunell R, Anderson D, Gellar D,et al. Sea-surface temperature estimates for the tropical western Pacific during the last glaciation and their implications for the Pacific warm pool[J]. Quaternary Research,1994,41:255-264.
[6] Martinez I J. Late Pleistocene paleoceanography of the Tasman Sea:Implications for the dynamics of the warm pool in the western Pacific[J]. Paleogeography,Paleoclimatology,Paleoecology,1994,112:19-62.
[7] Wang P X. Response of Western Pacific marginal seas to glacial cycles:paleoceanography and sedimentological features[J]. Marine Geology,1999,156:5-39.
[8] 汪品先,田军,成鑫荣. 第四纪冰期旋回转型在南沙深海的记录[J]. 中国科学D辑,2001,31(10):793-799.
[WANG Pin-xian,TIAN Jun,CHENG Xin-rong. Transition of Quaternary glacial cyclicity in deep-sea records at Nansha,the South China Sea[J]. Science in China (Series D),2001,31(10):793-799.]
[9] Jian Z M,Wang P X,Chen M P,et al. Foraminiferal responses to major Pleistocene paleoceanographic changes in the southern South China Sea[J]. Paleoceanography,2000,15(2):229-243.
[10] Lea D W,Pak D K,Spero H J. Climate impact of late Quaternary equatorial Pacific sea surface temperature variations[J]. Science,2000,289:1719-1724.
[11] Visser K,Thunell R,Stott L. Magnitude and timing of temperature change in the Indo-Pacific warm pool during deglaciation[J]. Nature,2003,421:152-155.
[12] Garidel-Thoron T,Rosenthal Y,Bassinot F,et al. Stable sea surface temperatures in the western Pacific warm pool over the past 1.75million years[J]. Nature,2005,433:294-298.
[13] 金海燕,翦知湣,刘东升. 西太平洋翁通-爪哇海台晚第四纪浮游有孔虫群与古温度变化[J]. 海洋地质与第四纪地质,2003,23(4):65-71.
[JIN Hai-yan,JIAN Zhi-min,LIU Dong-sheng. Late Quaternary variations of planktonic foraminiferal assemblage and paleo-temperature of Ontong-Java plateau,West Pacific[J]. Marine Geology and Quaternary Research,2003,23(4):65-71.]
[14] Thompson P. Planktonic foraminifera in the Western North Pacific during the past 150000 years:comparison of modern and fossil assemblages[J]. Paleogeography, Paleoclimatology, Paleoecology,1981,35:241-279.
[15] Le J N,Shackleton N J. Carbonate dissolution fluctuations in the western equatorial Pacific during the late Quaternary[J]. Paleoceanography,1992,7(1):21-42.
[16] Berger W H. Preservation of foraminifera[C]//Foraminiferal Ecology and paleoecology. SEPM Short Court Course,1979,6:105-155.
[17] Prentice M L,Friez J K,Simonds G G,et al. Neogene trends in planktonic foraminifer δ18O from site 807:implications for global ice volume and western equatorial Pacific sea-surface temperatures[J]. ODP Scientific Results,1993,130:281-283,295-298.
[18] Shackleton N J,Berger A,Peltier W R. An alternative calibration of the lower Pleistocene time scale based on ODP site 677[J].Trans. Royal Soc., Edingburg. Earth Sciences,1990,81:251-261.
[19] Bé A W H. An ecological,zoogeographic and taxonomic review of recent planktonic foraminifera[M]//Ramssy A T S,ed.Oceanic micropaleontology.London:Academic Press,1977,1.
[20] Thunell R C,Honjo S. Calcite dissolution and the modification of planktonic foraminiferal assemblages[J]. Marine Micropaleontology,1981,6:169-182.
[21] Levitus S, Boyer T P. World Ocean Atlas,Vol.4,temperature,NOAA Atlas NESDIS 4,Nati. Oceanic and Atmos,Admin,Silver Spring,Ma.[M]. 1994:117.
[22] Wang L J,Wang P X. An attempt at paleotemperature estimation in South China Sea using transfer function[J]. Chinese Science Bulletin,1989,34(1):53-56.
[23] Jian Z M,Zhao Q H,Cheng X R,et al. Pliocene-Pleistocene stable isotope and paleoceanographic changes in the northern South China Sea[J]. Palaeogeography,Palaeoclimatology,Palaeoecology, 2003,193:425-442.
[24] 黄宝琦,翦知湣. 越南岸外晚第四纪上升流与东亚夏季风变迁[J]. 第四纪研究,1999,6:518-525.[HUANG Bao-qi,JIAN Zhi-min. Late Quaternary coastal upwelling and variations of the East Asian summer monsoon off the Vietnam coast[J]. Quaternary Sciences,1999
,6:518-525.]
[25] Huang B Q,Jian Z M,Cheng X R. Response of upper ocean structure to the initiation of the North Hemisphere glaciation in the South China Sea[J]. Palaeogeography,Palaeoclimatology,Palaeoecology, 2003,196:305-318.
[26] Li B H, Wang J L, Huang B Q,et al. South China Sea surface water evolution over the last 12Myr:A south-north comparison from Ocean Drilling Program Sites 1143 and 1146[J]. Paleoceanography 19,PA1009. doi:10.1029/2003PA000906.
[27] Wang L J, Wang P X. Late Quaternary paleoceanography of the South China Sea:glacial-interglacial contrasts in an enclosed basin[J]. Paleoceanography,1990,5:77-90.
[28] ZHENG Fan,LI Qian-yu,LI Bao-hua,et al. A millennial scale planktonic foraminifer record of the mid-Pleistocene climate transition from the northern South China Sea[J].Palaeogeography,Palaeoclimatology,Palaeoecology, 2005,223:349-363.
[29] Xu J,Wang P X, Huang B Q,et al. Response of planktonic foraminifera to glacial cycles:Mid-Pleistocene change in the southern South China Sea[J]. Marine Micropaleontology,2005,54:89-105.
[30] Andreason D J, Ravelo A C. Tropical Pacific Ocean thermocline depth reconstructions for the last glacial maximum[J]. Paleoceanography,1997,12(3):395-413.
[31] Ravelo A C,Shackleton N J. Evidence for surface-water circulation changes at site 851 in the eastern tropical Pacific Ocean[J]. ODP Scientific Results,1995,138:503-514.
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