两高分辨率黄土剖面末次冰消期气候事件的差异探讨

高分辨率黄土剖面的获取使我们对亚轨道时间尺度上的气候事件的研究成为可能。通过对六盘山东、西部两个高分辨率黄土剖面与GRIP冰芯记录的对比研究,我们发现两剖面都捕捉到了末次冰消期内的Younger Dryas 事件与Heinrich-1事件及Blling和Allerd事件,并且它们在时间上与冰芯的结果较为一致。更为重要的是,这些亚轨道时间尺度上的气候事件在东西两剖面内存在较大差异:Heinrich-1事件在西面沙沟剖面的烙印较东面的王官剖面要深;对于Blling和Allerd事件,沙沟剖面较王官剖面的波动要多;在沙沟剖面,Younger Dryas 的结束是一种突变行为,而在王官剖面中则是一种渐变行为;此外,沙沟剖面比王官剖面表现出更大的波动幅度和更多千年尺度上的快速波动。初步推测上述差异是由高、低纬地区对它们影响的不同所造成的。

Discuss on Difference of Climate Change Events Recorded in Two High-Resolution Loess Sections in Last Deglaciation

Since high-resolution loess section makes it possible to study the climate change events in sub-trajectory time scale, we compared the record of two high-resolution loess sections in China with the GRIP ice core record to research climatic changes. The two loess sections are located at Wangguan, which is on the east of Liupanshan Mountain, and Shagou, which lies to the west of Liupanshan Mountain, separately. The results showed that both of the two sections recorded the Younger Dryas, the Heinrich-1 and the B lling &; Aller d in last deglaciation. Moreover, those events recorded in loess sections occurred almost at the same time with those recorded in ice core. And we also found that the characters of those climate change events in the two loess sections, were quiet different from each other. It indicated that: ①the Heinrich-1 in Shagou Section was more obvious than that in Wangguan Section; ②the B lling &; Aller d recorded in Shagou Section have more fluctuation than that in Wangguan Section; ③in Shagou Section, the Younger Dryas terminated suddenly while that one in Wangguan Section came to an end gradually; ④the record showed larger fluctuant range and higher frequency in millennial cycle in Shagou section than those in Wangguan Section. After analyzing, we initially assumed that the differences above were caused by the effect of the regional difference in latitude.