“河套东南角理想剖面”的新近研究

以在萨拉乌苏河流域近年命名的“米浪沟湾地层剖面”作为河套东南的理想剖面,描述了其地层特征,讨论了地层磁化率值和粒度分布与气候变迁的关系,研究提出,该剖面记录了150ka BP以来毛乌素沙漠27个旋回的砂丘与河湖相和古土壤互为交替的演化历史;剖面风成砂丘的堆积时期和河湖相或古土壤发育时期分别主要与过去冬季风和夏季风作为加强有关。根据中国沙漠及黄土区现代沙尘暴发生的区域特征认为,米浪沟湾剖面记录的150ka来的27次砂丘期代表了中国沙区存在27个沙漠堆积时期。

Recent Study on the "Ideal Section in the Southeast Corner of Ordos"

Taking "Milanggouwan section" located in the Salawusu River valley termed in recent years as an ideal profile in the southeastern margin of Ordos Plateau, the stratigraphic characteristics in the section and the relation between the stratigraphical magnetic susceptibility values, grain-size distributions and climatic changes have been discussed in this paper. It is pointed by studies out that the section takes down 27 cycles of alternately evolutionary histories of desert depositions in the Mu Us Desert with the fluvio-lacustrine facies and palaeosols since 150 ka BP and that the sedimentary periods of the aeolian dune and fluvio-lacustrine facies or palaeosol are chiefly apart related to intensifying winter monsoon and summer monsoon. Based on the regional feature that the contemporary sand-dust storm take place, it is considered that the 27 periods of dune accumulations recorded in Milanggouwan section represent 27 periods of desert deposition in China in past 150 ka.