澧阳平原晚冰期短尺度气候变化的风成沉积物稀土元素和粒度记录

Short-term Climate Events in Late Glacial Recorded by Rare Earth Elements and Sedimentary Grain-size in Tableland Profile in Liyang Plain,Hunan

对澧阳平原SL剖面的系统采样和室内稀土元素分析、粒度分析和AMS14C年代测定,揭示了澧阳平原岗地黄土剖面成因特征,探讨了澧阳平原晚冰期短尺度的气候变化过程。结果表明,澧阳平原岗地黄土在稀土元素配分模式上与黄土高原黄土-古土壤、镇江下蜀黄土具有高度的一致性,而且岗地剖面沉积物无任何水流作用痕迹,因此表明,澧阳平原岗地黄土剖面为风成成因。粒度结果表明,SL剖面较好地记录了晚冰期短尺度的气候变化过程,SL遗址剖面自然沉积物记录了晚冰期千年尺度的气候事件,如BL事件、OlderYD事件、AL事件、YD事件。SL剖面全新世早期表现为升温阶段,9.0～8.00kaBP的彭头山文化在此区兴起,表明此时气候相当适宜,适合人类生存。

Based on field investigation,sampling,and experimental analysis such as grain size and rare earth elements（REE） analysis,as well as AMS14C dating at the SL soil profile in the Liyang plain,the soil formation process has been revealed,and the short-term climate change events in Late glacial have been determined.The results show the REE distribution patterns of sediments from SL soil profile in Liyang Plain is similar to those of loess-paleosol in the Loess Plateau,and Xiashu loess in Zhenjiang.Moreover,field investigation results show the sediments have no trace of fluvial.Therefore,sediments from SL profile were formed by dust depositions.The results of grain-size analysis proved that the SL profile has well recorded the climate change processes in Late glacial,and high-resolution climate events were revealed,such as BL event （14.74 ka BP to 13.82 ka BP）,Older YD event （13.82 ka BP to 12.86 ka BP）,AL event （12.86 ka BP to 11.46 ka BP）,YD event （9.9 ka BP to 9.00 ka BP）.During 9 000～8 000 a BP,the weather was so good that people moved to the tableland in Liyang Plain,resulting in the rising of PengTouShan culture some connection with the paleolithic and Neolithic culture in middle reaches of Changjiang River.