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博乐地区地处西风区,是新疆黄土的重要分布区之一。选择该区一个厚为11 m的黄土剖面作为研究对象,测试与分析了磁化率、粒度、TOC、CaCO(3%)等指标。结果显示,磁化率的平均值远远低于黄土高原典型黄土的磁化率值,磁化率的变化过程也同黄土高原典型黄土相反;粒度组成以粗粉砂(63~10μm)为主,粘土(<5μm)、细粉砂(5~10μm)和砂(>63μm)含量较少。相关性分析结果显示粘土和细粉砂与磁化率呈现较明显的负相关关系,而砂含量对磁化率的影响最为显著,分析其原因可能与沉积物的来源有关;由于TOC含量很少,对磁性矿物的生成和阻碍其老化方面贡献较小,再加上TOC自身的磁性也极其微弱,所以对磁化率的影响较小;CaCO3含量与磁化率相关关系不显著。由此可见,该区黄土沉积物磁化率影响因素较为复杂,进一步表明在该区如果用磁化率作为气候代用指标来恢复和重建古气候、古环境时需要更多的结合其它气候代用指标,多指标分析和合成解释其结果可能更可靠准确。
Bole area is located in the westerly region, Xinjiang is one of the important distribution of loess. A section of loess with a thickness of 11 m was selected as the study object to test and analyze the indexes of magnetic susceptibility, grain size, TOC, CaCO (3%) and so on. The results show that the average value of magnetic susceptibility is far lower than that of the typical loess in the Loess Plateau, and the change of magnetic susceptibility is opposite to that of the typical loess in the Loess Plateau. The coarse grain silt (63 ~ 10μm) <5μm), fine silt (5 ~ 10μm) and sand (> 63μm) content is less. Correlation analysis showed that there was a significant negative correlation between magnetic susceptibility and clay and fine silt, while the influence of sand content on magnetic susceptibility was the most significant. The reason for this may be related to the source of sediments. Due to the small amount of TOC, The contribution of magnetic minerals to the formation and retardation of aging is negligible. In addition, the magnetic properties of TOC itself are extremely weak, so the effect on magnetic susceptibility is small. The correlation between CaCO3 content and magnetic susceptibility is not significant. It can be seen that the influencing factors of the susceptibility of loess sediments in this area are complicated, which further indicates that if the magnetic susceptibility is used as a proxy for climate to restore and reconstruct paleoclimate and paleoenvironment in this area, more indicators should be used in combination with other climatic proxy indicators Indicators and synthetic interpretation of the results may be more reliable and accurate.