山东埠西黄土剖面沉积特征及古气候环境意义

对山东济南章丘埠西黄土剖面进行了系统的野外调查,并对山东章丘埠西黄土剖面进行了粒度、磁化率以及光释光测年等指标研究分析,结果表明：① 根据粒度测量数据和粒度参数变化特征,并运用萨胡判别公式对其沉积环境进行判别,可知山东埠西剖面黄土沉积主要为风成沉积。通过粒级—标准偏差方法提取的环境敏感粒级分别为7.08~8.91 µm和39.81~50.12 µm;② 磁化率变化与不同粒级百分含量的变化之间具有明显的相关性,其中低频磁化率变化范围为32.38×10^-8~138.46×10^-8m³kg^-1,高频磁化率在 30.62×10^-8~123.31×10^-8m³kg^-1 之间变化,其变化特征一定程度上反映了埠西黄土剖面形成时的古气候环境信息;③ 结合光释光年代的测量数据与前人的研究成果,可将该黄土剖面划分为3个黄土层和3个古土壤层,该剖面记录了末次冰期以来该区域古气候环境的变化历史过程。

The sedimentary characteristics of Buxi loess profile in Shandong Province and their paleoclimatic and palaeoenvironment significance

Field work was carried out systematically on one loess section at Buxi of Zhangqiu in Shandong Province. Grain size, magnetic susceptibility and optically stimulated luminescence (OSL) dating of Buxi loess section were conducted. Results indicate that: (1) According to Sahu's discrimination formula, it is found that the main sedimentary deposits are formed in aeolian environment. By analyzing grain-size class vs. standard deviation values method, environment-sensitive size fractions of this section are 7.08-8.91 µm and 39.81-50.12 µm respectively; (2) Changes of magnetic susceptibility and percentages of different size fractions are correlated. In this section, the quality of low-frequency and high-frequency magnetic susceptibility changes in the range of: 32.38×10^-8-138.46×10^-8 m³ kg^-1 and 30.62×10^-8-123.31×10^-8 m³ kg^-1 (ranges from A to B). The change of magnetic susceptibility can reflect the palaeoclimate variation information to some extent; (3) The section is divided into three loess layers and three paleosol layers, which records the information of climatic change and environmental evolution over the last interglacial stage.