8 ka来东海内陆架泥质区高分辨率沉积记录对东亚冬季风的响应

Response of high-resolution sedimentary records to East Asian winter monsoon in the inner shelf of the East China Sea over the past 8000 years

依据东海内陆架泥质区D03钻孔岩芯沉积物高分辨率粒度分析结果,筛选了对东亚冬季风有良好显示的敏感粒级,结合高精度年代框架,揭示了近8 ka以来东亚冬季风波动在泥质区的沉积记录,包括11个千年尺度的气候波动事件和5.4~4.9、1.8 kaBP以来的百年尺度的快速气候波动。与石笋、冰芯和泥炭的氧同位素曲线对比发现,东亚冬季风增强与世界范围的“8.2 ka”、“4.9 ka”、“3.8 ka”、“1.4 ka”和小冰期事件均有良好的对应关系,建立了全新世东亚冬季风增强与气候变冷事件的内在联系。8 ka以来东亚冬季风的演化大致可以分为3个阶段,即8.2~4.8 kaBP中高频波动期、4.8~1.8 kaBP波动较弱稳定期和1.8 kaBP以来的高频波动期。

Through high resolution AMS14C dating and grain size analysis on upper layer sediments of the core D03 in the muddy area of inner shelf of the East China Sea,three sensitive grain groups were extracted and used as proxies of East Asian winter monsoon strength.During the past 8 ka,eleven millennium scale events and centennial scale rapid climatic events during 5.4~4.9 kaBP and in the past 1.8 kaBP were revealed.By comparison with records of other proxies from oxygen isotopes of stalagmites,ice cores and peat,it is indicated that the enhancement of East Asian winter monsoon in the study area was well correlated with the global cooling events,e.g."8.2 ka","4.9 ka","3.8 ka","1.4 ka"and Little Icea Age.The inner relationship between the East Asian winter monsoon enhancement and the climate cooling event during the Holocene was established.The evolution of the East Asian winter monsoon in the past 8000 years can be roughly divided into three stages,including the intermediate and high frequency fluctuation stage during 8.2~4.8 kaBP,the weak and stable stage during 4.8~1.8 kaBP,and the high frequency fluctuations stage since 1.8kaBP.