宁夏长城塬全新世黄土-古土壤序列微形态特征及意义

利用偏光显微镜对宁夏长城塬全新世黄土-古土壤序列(CCY)的微形态特征进行了详细观察和分析。结果表明,S0层的粗颗粒形态参数（如C/F(10 μm)、面积、周长、等圆直径等）以及土壤形成物、孔隙、微垒结等微形态指标明显区别与黄土层L层,其中C/F(10 μm)值在全剖面中达到最小值,孔隙度达到最大值,残积黏土铁染程度最强烈,指示出古土壤S0层受到的风化作用较为强烈,成壤强度较强。同时,微形态变化能够与磁化率、CaCO3、粒度含量变化进行良好的对比;通过对比得出C/F(10 μm)值、孔隙度、土壤形成物存在形式也可作为指示气候变化的一个重要指标。

Significance of Micro-morphological Features of the Holocene Loess-paleosol Profile in Loess Plateau

The micro-morphological characteristics of a Holocene loess-paleosol sequence in Changchengyuan (CCY) of Ningxia were observed in detail with a polarizing microscope. The shape parameters of coarse particles in the paleosol, S0 (e.g., C/F(10 μm), area, perimeter, diameter and so on) and the micro-morphological indices (for example, pedogenetic features, porous, and micro-fabric) are obviously different from loess layer, L. In S0,C/F(10 μm) is the minimum in the entire profile, porosity is the maximum, and the degree of residual clay dipped by iron is the most intense. These features indicate the paleosol S0 suffers the most intense weathering, and the intensity of pedogenesis is significant. The micro-morphological changes in profile are well parallel to that of magnetic susceptibility, CaCO3, and granularity, so the C/F(10 μm) value, the porosity, the pedogenetic features may be used as key proxies indicating climatic change.