位于中国北方半干旱区的毛乌素沙地对气候变化响应敏感,是研究气候变化的理想区域。通过对毛乌素沙地东南部锦界剖面磁化率、有机质含量、CaCO_3含量的分析,重建了7.5 ka BP以来的气候变化过程。结果显示: 中晚全新世毛乌素沙地东南部环境与气候变化可分为3个阶段: 7.5 ~ 4.6 ka BP,夏季风占主导,气候暖湿,与全新世大暖期对应; 4.6 ~ 3.3 ka BP,气候突变为干冷并波动频繁; 3.3 ~ 2.5 ka BP气候以干冷为主。另外,存在5次千年尺度的干旱事件: 7.0 ~ 6.8 ka BP、6.6 ~ 5.7 ka BP、4.6 ~ 4.1 ka BP、3.7 ~ 3.5 ka BP、3.3 ~ 2.5 ka BP。研究区气候变化与全球具有较好的一致性。
英文摘要:
The Mu Us Sandy Land is located at semi-arid region of North China, and it is sensitive to climate changes. The climate change process in the southeastern Mu Us Sandy Land since 7.5 kyr BP was reconstructed based on data of magnetic susceptibility, organic matter, CaCO_3, 14C and OSL dating. The variations of the indices suggest environment and climate changes in the Mu Us Sandy Land can be classified into 3 stages. In 7.5-4.6 kyr BP, corresponding to the Holocene Climatic Optimu, the summer monsoon was powerful and the climate is warm and wet. In 4.6-3.3 kyr BP, with frequently alternations of the climate and an abruptly shift at 4.6 kyr BP, the weakening summer monsoon dominated this period. The climate was cold and arid. In 3.3-2.5 kyr BP, the cold and dry climate was dominated. Additionally, five millennial-scale dry events were recorded at 7.0-6.8 kyr BP, 6.6-5.7 kyr BP, 4.6-4.1 kyr BP, 3.7-3.5 kyr BP and 3.3-2.5 kyr BP. In short, the regional climate change is correlated with the global climate change.