第四纪加积型红土与下蜀黄土理化特征比较

COMPARATIVE STUDY ON QUATERNARY RED EARTH AND XIASHU LOESS IN PHYSICAL AND CHEMICAL CHARACTERISTICS

加积型红土和下蜀黄土是我国亚热带地区常见的第四纪沉积物。测试了加积型红土的粒度、矿物与石英砂表面特征、磁化率、常量元素和稀土元素等理化指标,并与下蜀黄土进行了对比分析,结果表明,加积型红土与下蜀黄土在理化特征上具有整体相似性,显示风成特性,但较下蜀黄土经历了更为强烈的化学风化作用。同一剖面自下而上为加积型红土至棕黄色下蜀土的沉积序列,揭示了中更新世至晚更新世风化成壤强度减弱、气候由湿热向干凉转变的趋势;北亚热带和中亚热带沉积年代相当的下蜀土风化特征差异反映了古环境变化的纬度效应。

As Quaternary sediments,aggradational red earth and Xiashu Loess are frequently seen in the subtropical zone in China.Grain-size,quartz surface characteristics,magnetic susceptibility,and REE of red earth are tested and compared with Xiashu Loess.The results show that,generally,the physical and chemical characteristics of red earth and Xiashu Loess are similar to each other,indicating aeolian characteristics.However,red earth shows stronger weathering properties.At the same section,the bottom-up sedimentary...