文汉锋, 赵楠钰, 刘成程, 周鹏超, 王国桢, 晏宏. 西太平洋帕劳砗磲高分辨率氧同位素记录及其指示的气候环境变化[J]. 海洋地质与第四纪地质, 2021, 41(1): 1-13. DOI: 10.16562/j.cnki.0256-1492.2020101101
引用本文: 文汉锋, 赵楠钰, 刘成程, 周鹏超, 王国桢, 晏宏. 西太平洋帕劳砗磲高分辨率氧同位素记录及其指示的气候环境变化[J]. 海洋地质与第四纪地质, 2021, 41(1): 1-13. DOI: 10.16562/j.cnki.0256-1492.2020101101
WEN Hanfeng, ZHAO Nanyu, LIU Chengcheng, ZHOU Pengchao, WANG Guozhen, YAN Hong. High-resolution oxygen isotope records of Tridacna gigas from Palau, Western Pacific and its climatic and environmental implications[J]. Marine Geology & Quaternary Geology, 2021, 41(1): 1-13. DOI: 10.16562/j.cnki.0256-1492.2020101101
Citation: WEN Hanfeng, ZHAO Nanyu, LIU Chengcheng, ZHOU Pengchao, WANG Guozhen, YAN Hong. High-resolution oxygen isotope records of Tridacna gigas from Palau, Western Pacific and its climatic and environmental implications[J]. Marine Geology & Quaternary Geology, 2021, 41(1): 1-13. DOI: 10.16562/j.cnki.0256-1492.2020101101

西太平洋帕劳砗磲高分辨率氧同位素记录及其指示的气候环境变化

High-resolution oxygen isotope records of Tridacna gigas from Palau, Western Pacific and its climatic and environmental implications

  • 摘要: 砗磲是海洋中最大的双壳类贝壳,其碳酸盐壳体通常具有年纹层和天纹层,是一种理想的高分辨率古气候研究载体。氧同位素是砗磲古气候研究中最常用的指标之一,但在将其应用于古气候重建之前,通常需要对其现代地球化学过程进行准确的校准。帕劳群岛位于西太平洋暖池西北边缘,其珊瑚礁盘具有丰富的砗磲壳体资源,为开展古气候研究提供了丰富的材料。在本次研究中,对采自帕劳群岛的现代活体库氏砗磲(Tridacna gigas)PL-1的内层壳体进行了高分辨率氧同位素分析,同时利用该砗磲较为清晰的天生长纹层对氧同位素的年代学框架进行了标定。结果表明,该砗磲壳体的氧同位素没有明显的变化趋势,说明砗磲个体的生命效应对氧同位素没有显著影响;砗磲壳体氧同位素没有清晰的年周期变化,常出现不规则的毛刺状峰值。结合现代器测资料分析发现,帕劳砗磲内层壳体的氧同位素记录了热带太平洋ENSO活动对该区域水文气候变化的影响。该研究结果表明,帕劳砗磲内层壳体天生长纹层和氧同位素,具有用于开展高分辨率古气候研究的潜力。

     

    Abstract: Tridacna gigas is the largest marine bivalve, and its hard and dense aragonite shells usually have annual and daily growth lines, which have been demonstrated to be an ideal material for high-resolution paleoclimate research. The oxygen isotope has been widely used in Tridacna paleoclimate studies. However, the oxygen isotope of Tridacna shells must be accurately calibrated by modern geochemical process before paleoclimate reconstructions. Palau is located in the northwestern edge of the Western Pacific Warm Pool. Long-lived Tridacna spp. is a common species in the coral reefs of Palau Islands, which may provide abundant materials for paleoclimate reconstructions. In this study, we present a high-resolution oxygen isotope profile from the inner shell of a modern living T. gigas specimen PL-1 from Palau. The high-resolution chronology of the oxygen isotope profile is determined by the clear daily growth layers in the inner shell. The result suggests that the δ18Oc profile of the T. gigas shell has no obvious trend, indicating that the vital effects have no significant influence on the oxygen isotope of shell. Combining with the instrumental data, we found that the ENSO activities in the tropical Pacific had impacts on the regional hydro-climate changes of Palau, and left some fingerprint in the oxygen isotope of Tridacna shell. This study indicates that the daily growth layer and the oxygen isotope in the inner shell of Tridacna from Palau have the potential for high-resolution paleoclimate research.

     

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