萨拉乌苏河流域MGS1层段微量元素记录的全新世千年尺度的气候变化

本文以毛乌素沙漠东南缘萨拉乌苏河流域米浪沟湾剖面MGS1层段为代表,试图通过对其的微量元素分析结果探讨该地全新世千年尺度的气候变化.在分析的14种微量元素中,除Cr和Zn以外的12种元素P、Pb、Rb、Nb、Zr、V、Sr、Cu、Ni、As、Ba、Co含量在MGS1剖面的垂直方向上具有这样的分布规律:元素含量值在沙丘砂...

The kyr-scale climate change recorded by the trace elements in MGS1 of the Salawusu River Valley during Holocene

The analysis of trace chemical elements shows that Mu Us Desert has been repeatedly subjected to the alternating East Asian winter and summer monsoon during Holocene. The high value of trace chemical elements in lacustrine and / or paleosols overlying the dune sand sediment, is tightly related to the special location of the low-lying area between the Ordos Plateau and the Loess Plateau under the wet climate condition. The alternating peak and valley of trace chemical elements content can be nearly regarded as the alternating deposition-climate cycles of the dry-cold climate with aeolian sand accumulating and the relatively warm-wet climate with the lacustrine or paleosol accumulating, these cycles amount to 11 in the MGS1. To reveal the cause and process, this paper first introduces the formation sequences of MGS1 with their ages and the grain-size analysis for the lithologic characteristics of each layer, then presenting the distribution characteristics of trace chemical elements in MGS1. It indicates that the distribution of most elements remains low valley in the present and paleo dune sands, whereas, high peaks appearing in the overlying lacustrine or paleosol. The content characteristics of trace elements in different sedimentary facies and the reflected climate are further analyzed. Finally, the cold events indicated by the dune sands are compared to those recorded by the deep-sea sediment in North Atlantic, which results in well coupling. It shows that the distribution of the trace elements and the revealed kyr-scale climate change in MGS1of Milangguowan section are due to the mutual evolution of the East Asian winter and summer monsoon caused by the sudden global climate change.