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本文分析了天山北麓不同海拔高度的两个黄土剖面粒度、磁化率特征及其古气候意义的差异性。结果表明,位于海拔2074m的鹿角湾剖面与海拔527m处的大佛寺剖面黄土粒度特征比较相近,但鹿角湾剖面黄土整体细于大佛寺黄土,并且其细颗粒分布范围也大于大佛寺剖面,而粗颗粒的则相反。鹿角湾剖面中全新世以来地层磁化率与成壤作用相关,显示成壤增强模式,其下末次冰期地层磁化率及大佛寺剖面磁化率与粗颗粒沉积相关,显示风速论模式。造成两个剖面粒度及磁化率差异的原因主要是地形导致的沉积颗粒分选及降水量不同引发的成壤作用差异。全新世中期以来大佛寺剖面记录的气候整体处于干旱状态,而鹿角湾剖面同时期地层受地形影响则记录了相对湿润的气候。
This paper analyzes the grain size and magnetic susceptibility of two loess sections with different altitudes at the northern foot of the Tianshan Mountains and their paleoclimatic significance. The results show that the loess particle size is similar to that of the Dafosi Section at 527m above sea level at an altitude of 2074m, but the whole loess area of the Antler Bay section is thinner than that of the Dafosi Lake, and the distribution range of fine particles is larger than Dafosi profile, while the coarse particles are the opposite. Since Holocene, the stratigraphic susceptibility of the Antler Formation correlates with pedogenesis. It shows that the mode of pedogenesis is increasing, and the magnetic susceptibility of the next glacial stage and the magnetic susceptibility of the Dafosi profile correlate with the coarse grain sediment. The main reason for the difference in grain size and magnetic susceptibility between the two sections is the difference in the pedogenesis caused by the sediment particle sorting and precipitation caused by the terrain. Since mid-Holocene, the recorded climate of the Dafosi section has been in a dry condition, while the stratum of the Antler Bay section has recorded a relatively humid climate under the influence of the terrain.