南京江北地区下蜀黄土粒度分形与全新世环境演变

Grain-size Fractal Distribution of Xiashu Loess and Holocene Environmental Change in North of Yangtze River,Nanjing

根据分形理论，对南京江北下蜀黄土剖面不同层位样品进行分形维数定量计算。计算结果表明：粒度的分形维数与黄土和古土壤层位具有良好的对应关系，对沉积和成壤环境具有很好的指示意义。全新世最适宜期（8500-3100aBP）发育的古土壤层位（S0）分形维数最高，其维数平均值为2．7237，明显高于全新世晚期（3100aBP）形成的表土层（Ts）和末次冰期堆积的黄土层（L1）分形维数，其平均值分别为2．3823、2．351，全剖面维数平均值则为2．5063，造成它们的差别可能是由于受到不同的成壤强度影响导致土壤颗粒分选性差异所致。

On the basis of fractal theory, the samples of Xiashu loess are used to calculate the grain-size fractal dimension in the TZC profile in different layers. The results show that grain-size fractal dimension is related to loess and paleosol closely, which can be regarded as good indictor of deposition and pedogenic environment. Between 8 500-3 100 a BP, pedogenic process is strong. A layer of Huangzong soil（So）was developed in North of Yangtze River in Nanjing, whose mean fractal dimension（2. 7237） is highest. The second is the top layer（2. 3823）, which was formed since 3100 a BP. And the Xiashu Loess layer（L ）is 2. 351. The difference between them is that the pedogenic environment is different.