地理科学进展 ›› 2010, Vol. 29 ›› Issue (1): 79-86.doi: 10.11820/dlkxjz.2010.01.011

• 生态与环境变化 • 上一篇    下一篇

辽东半岛黄土粒度分维特征及其环境意义

张威|郭善莉|李永化|李云艳   

  1. 辽宁师范大学城市与环境学院|大连 116029
  • 出版日期:2010-01-25 发布日期:2010-01-25
  • 通讯作者: 张威(1969-),男,吉林松原人,教授,博士,主要从事环境与灾害地貌研究。 E-mail:zhangweilnu@163.com
  • 基金资助:

    国家自然科学基金项目(40571016);辽宁省教育厅高等学校科学研究项目(20060467)

Grain-size Fractal Dimension of Loess and Its Environmental Significance in the Peninsula of East Liaoning

ZHANG Wei, GUO Shanli, LI Yonghua, LI Yunyan   

  1. College of Urban Environmental Sciences, Liaoning Normal University, Dalian 116029, Liaoning, China
  • Online:2010-01-25 Published:2010-01-25

摘要:

应用分形理论中的幂指函数关系法,分别选取粒径r区间和质量累计百分含量5%~95%的范围为无标度区,对辽东半岛黄土的粒度分维特征进行分析。结果显示:以粒径r区间为无标度区(0.76~263.75 μm),七顶山马兰黄土的粒度分维值介于2.2085~2.3184之间,平均值为2.2744,相关系数为0.8835;离石黄土粒度分维值介于2.2748~2.4237之间,平均值为2.3467,相关系数为0.8920。全剖面粒度分维值在2.2085~2.4237之间,平均值为2.3187,相关系数达0.88以上,粒度分布具有分形特征。而以质量累计百分含量5%~95%的范围为无标度区,马兰黄土分维值介于2.4220~2.5042之间,平均值为2.4761,相关系数为0.9889,分选系数为2.4067;离石黄土分维值介于2.4268~2.545之间,平均值2.4993,相关系数为0.983,分选系数为2.5097。全剖面分维值介于2.422~2.545之间,相关系数达0.98以上。研究得出:分维值的大小对黄土的形成环境有良好的指示意义,对同一种成因以及不同种成因的沉积物分维特征研究应注意无标度区的选择。本区马兰黄土比离石黄土的分维值低,反映马兰黄土沉积时东亚冬季风强盛,气候寒冷干燥,分选系数偏小,自组织程度低;离石黄土沉积时夏季风较冬季风强盛,气候温暖湿润,分选较差,分选系数稍大,自组织程度高,与传统粒度分析所反映的环境演变一致。

关键词: 黄土粒度;分维值;环境变化;辽东半岛

Abstract:

On the basis of the fractal theory and the selection of different methods of non-criterion degree, this paper analyzes the fractal characters of the loess deposits in the Peninsula of East Liaoning. Used the scale of particle size as the non-criterion degree, the fractal dimension value of Malan Loess is between 2.2085 and 2.3184, with an average of 2.2744, and the correlation coefficient of 0.8835. The value of Lishi Loess is between 2.2748 and 2.4237, with an average of 2.3467, and the correlation coefficient of 0.8920. The whole profile fractal dimension value is between 2.2085 and 2.4237, an average of 2.3187, and the correlation coefficient of more than 0.88. However, taking the scale of percentage of cumulating weight as the non-criterion degree, the fractal dimension value of Malan Loess is between 2.422-2.5042, with an average of 2.4761, and the correlation coefficient of 0.9889. The value of Lishi Loess is between 2.4268-2.545, with an average of 2.4993, and the correlation coefficient of 0.983. The whole profile fractal dimension value is between 2.422-2.545, with the correlation coefficient of more than 0.98. Compared with other regions, the grain-size distribution has good fractal characteristics. Fractal dimension of size in the environment for the formation of the Loess can be used as a good index. Selection of non-criterion degree should be taken into account during the research of the deposits with the same/different origins. The fractal dimension of Malan Loess is lower than Lishi Loess, which indicates that Malan Loess deposited at the stage of strengthening of the East Asian winter monsoon with a cold and dry climate, and also with a small sorting coefficient. The sorting of the Malan Loess is slightly better than that of the Lishi Loess, suggesting that there are the low level of self-organization and the low-dimensional value. The Lishi Loess was deposited when the summer monsoon became stronger with a warm and humid climate. Poor separation and slightly larger sorting coefficient show that there is the higher degree of self-organization and fractal dimension.

Key words: environmental change, fractal dimension, grain-size, Loess, Qiding hill