南京林峰桥剖面记录的22600—18550aBP的环境演变信息

INFORMATION OF ENVIRONMENTAL EVOLUTION DURING 22 600—18 550a BP INFERRED FROM THE LINFENGQIAO PROFILE, NANJING

通过对林峰桥剖面的磁化率值,Rb、Sr含量和14C年代等的测定,发现在21070aBP前后,磁化率值异常增高,Rb/Sr比值降低,揭示出南京江北地区在这一时段,风化淋溶作用不强,可能经历了一次突然的气候冷干事件,与北半球广泛记录的Heinrich事件的H2同时期,可能是Heinrich事件在东亚季风区的又一响应。

Analyses of the magnetic susceptibility, the content of Rb and Sr elemental geochemisty and ^14C dating of the Linfengqiao profile suggest that the magnetic susceptibility increases remarkably, and that the Rb/Sr ratio drops abruptly about 21 070a BP. These data indicate that during this period chemical weathering and eluviation were weak in the north bank of Yangtze River, possibly recording a cold-dry environment at that time. This cold-dry event may be coeval with the Heinrich2 event which is widely recorded in the Northern Hemisphere. Thus it may represent a climatic response of the Heinrich2 event in the eastern Asia monsoon area.