浑善达克沙地磁化率和有机质揭示的全新世气候变化  

Climate Change Revealed by Magnetic Susceptibility and Organic Matter during the Holocene in Hunshandak Desert

作　　者：李明启[1] 靳鹤龄[1] 张洪[1] 苏志珠[2] 孙忠[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,兰州730000 [2]山西大学黄土高原研究所,太原030006

出　　处：《沉积学报》2005年第4期683-689,共7页Acta Sedimentologica Sinica

基　　金：国家重点基础研究发展规划(G2000048701)"中国北方沙漠化过程及其防治研究";中国科学院知识创新工程重要方向项目(KZQCX3-SW-341);中国科学院寒区旱区环境与工程研究所知识创新项目共同资助.

摘　　要：根据浑善达克沙地锡林浩特剖面磁化率、有机质等气候代用指标的变化特征和14C测年结果,分析和讨论了浑善达克沙地10.7kaBP以来的气候变化过程.实验数据显示地层剖面磁化率和有机质值的变化趋势基本一致,且峰值段对应古土壤层,谷值段对应风成砂层.依据磁化率和有机质含量的变化将浑善达克沙地全新世气候变化分为5个阶段:10.7～8.5 kaBP,气候相对冷干,冬季风较强,夏季风相对较弱,但有增强趋势;8.5～5.8 kaBP,气候温暖湿润,夏季风较强,冬季风相对较弱,与全新世最适宜期对应;5.8～3.5 kaBP,气候波动变化频繁,但夏季风和冬季风都相对较弱;3.5～1.9 kaBP,气候温暖湿润,仅次于全新世最适宜期,夏季风较强,冬季风相对较弱;1.9 kaBP以来,气候波动渐变冷干,冬季风逐渐波动增强,夏季风相对逐渐减弱.并且其气候变化与全球变化具有较好的一致性.Hunshandak desert is located in the west of Inner Mongolia, China. This region is sensitive to climate change with annual temperature between 0.9 -5.5℃ and annual precipitation between 240.3 -422.6 ram. The samples were gotten at 5-cm intervals in Xilinhaote section （N43°52′36.6″, E116°05′34.1″）which is 2.8m high and lies in Hunshandak desert. In the laboratory the character of magnetic susceptibility and organic matter were analyzed. The trend that magnetic susceptibility changes is very similar to organic matter. The climate is warm and humid when the values of magnetic susceptibility and organic matter are big, while the climate is cold and arid when they are small. According to the character of the magnetic susceptibility and organic matter, the climate changes can be divided into 5 stages： 10.7 -8.5 cal kaBP, cold and arid, the winter monsoon is stronger than the summer monsoon, but the summer monsoon is much stronger; 8.5 - 5.8 cal kaBP, warm and humid, the summer monsoon is much stronger than the winter monsoon and the period is consistent with the Holocene Optimum ; 5.8 - 3.5 cal kaBP, fluctuated frequently between cold/arid and warm/humid, and the winter and summer monsoon both are weak; 3.5 - 1.9 cal kaBP, warm and humid, but the summer monsoon is weaker than the Holocene Optimum; 1.9cal kaBP to present, the climate becomes colder and colder and arider and arider, the summer monsoon gets weaker and weaker. The climate changes in Hunshandak desert are similar with other regions in China and in the world.

关 键 词：浑善达克沙地 磁化率 有机质 气候变化 全新世 

分 类 号：P534.63[天文地球—第四纪地质学]