【摘要】 西宁盆地大墩岭黄土剖面Ｌ１、Ｌ２、Ｌ１５中存在３层古风成砂。沉积年代及各种环境记录的分析表明，这３层古风成砂分别代表了１．２ＭａＢ．Ｐ．以来西宁盆地在中更新世初、中更新世末和晚更新世晚期发生的３次较大规模的流沙活动。进一步分析得出西宁盆地的沙漠化正逆过程受制于第四纪全球气候波动变化以及青藏高原隆升的影响。第四纪青藏高原冰川的冰缘作用为其边缘的沙漠、黄土沉积提供了丰富的物质来源。更多还原

【Abstract】 There are three eolian paleosand layers existed in the loess profile of Dadunling, Xining Basin. The age and environmental records of the loess stratigraphy proved that these three eolian paleosand layers which represented three extensive desert expansion periods in Xining Basion since 1.2 Ma B.P. were formed in the early part and the latter part of the Middle Pleistocence, the latter part of the Last Pleistocence individually. Furthermore, the advance and the inverse processes of desertification in the studied area were controlled by the Quaternary climatic changes and the uplift of Qinghai Xizang plateau. In details, the periglacial action of plateau glacier in Quaternary has produced a lot of materal source for desert and loess deposition in adjacent areas.更多还原