220ka BP来萨拉乌苏河流域地质剖面地球化学特征及其对全球气候变化的响应

萨拉乌苏河流域位于我国北方沙漠/黄土过渡带和生态脆弱带,它对全球气候变化反映非常敏感,是研究全球气候变化响应的理想区域.对该区域滴哨沟湾剖面地球化学元素氧化物及其比值变化进行了分析,结果表明:约220 ka BP以来我国北方气候变化极不稳定,存在着不同时间尺度的频繁变化,这种不稳定性无论是在冰期还是间冰期都有很好的反映.其中倒数第二次间冰期存在3次气候波动;倒数第二次冰期存在7个气候旋回;末次间冰期存在7个气候旋回;末次冰期存在9个气候旋回.这些气候变化与深海氧同位素、极地冰芯反映的全球变化具有良好的对应关系,反映了该区气候变化与全球变化的高度一致性.

Geochemical Features of a Profile in Salawusu River Valley and Their Response to Global Climate Changes since 220 ka BP

The Salawusu River Basin is situated on the transition zone between desert and loess in North China and characterized a vulnerable ecotone,which sensitively responses to the global climate change.So,the basin is an ideal zone for studying climate changes in China.Commonly,the geochemical elemental oxides and their ratio can well reflect environmental change,which have been widely applied in the researches of Quaternary environmental and climatic changes.An ideal profile-Dishaogouwan Profile in Salawusu River basin was selected to study the climate changes in North China.The vertical sequence of geochemical elements and their ratios in the profile all indicated that the climate in North China has been very unstable since the Penultimate Interglacial Period,with frequent climate changes in different time periods.The climate of whether in the Ice Age or in the Interglacial Period was unstable.The climatic indexes in the Dishaogouwan Profile showed that there were three climatic fluctuations in the Penultimate Interglaciation,seven climatic cycles in the Penultimate Glaciation,seven cycles in the Last Interglaciation,and nine cycles in the Last Glaciation.These climate changes are well accordant with the global climate changes recorded in the deep-sea oxygen isotope and the polar ice cores,showing a consistency in time of climate changes between the study area and the globe.