萨拉乌苏河流域MGS1 Rb和Sr记录的全新世千年尺度气候变化

摘要

萨拉乌苏河流域米浪沟湾剖面全新世地层MGS1层段记录了11个由风成砂与河流相或湖沼相构成的沉积旋回。对该层段63个样品的Rb、Sr数据进行了分析，结果显示由沙丘砂至上覆河湖相Rb和Sr含量由低增高，而Rb/Sr比值的分布则显示出与Rb和Sr含量变化相反的趋势，三者与平均粒径Mz(f)的相关系数都在0.43以上。研究表明MGS1至少经历了11次冷干和11次暖湿的气候波动。米浪沟湾剖面MGS1记录的千年尺度气候波动既是对东亚季风环流演变历史的体现，同时也是对全球气候与环境变化的响应。%The MGS1 stratigraphical segment of Milanggouwan section is located in the Salawusu River Valley of southeast Mu Us Desert. The segment documents 11 sedimentary cycles consisting of aeolian facies and fluvial facies or lacustrine-swamp facies. Totally 63 samples were analyzed for rubidium (Rb) and strontium (Sr) concentrations. The results show that Rb and Sr concentrations increase as the sediments vary from aeolian facies to lacustrine-swamp facies, however, variation of the Rb/Sr ratios shows reversed trends in contrast to that of Rb and Sr concentrations. The line correlation coefficients of Rb and Sr concentrations and Rb/Sr ratios with mean grain size are all above 0.43. All these indicate that the MGS1 stratigraphic segment at least records 11 cold-dry and 11 warm-humid millennium-scale climatic oscillations, which represent the evolution history of East Asian monsoon circulation and show good correspondence to global climatic and environment variations.