吕梁山区西部黄土丘陵区水系分形特征及地质意义

The Fractal Feature and Geological Significance of Water System in the Loess Hilly Area in the Western Part of Lyuliang Mountain Area

基于分形理论对吕梁山区西部黄土丘陵区典型流域进行水系分维数的计算,论证该区水系存在的显著分形特征,并定量判断区内地貌发育阶段及构造意义。结果表明:研究区水系分维数介于1.02~1.44之间,处于地貌侵蚀发育的幼年阶段,河流下蚀切割作用强烈,河谷深切,多形成“V”型峡谷,北部河流坡降较大,侵蚀作用强烈,其分维数也较大,南部河流坡降较小,河流作用相对较弱,其分维数较小。黄土丘陵区覆盖的厚层黄土为地貌的发育提供了物质基础,同时吕梁山地的构造隆升为河流的发展和演化提供了势能与动能条件,进而对地貌进行进一步塑造。

Based on the fractal theory,the fractal dimension of the water system in the loess hilly area of the western Lyuliang Mountain area is calculated.The water system in this area has significant fractal characteristics,and the geomorphological development stage and tectonic significance are quantitatively judged.The results show that the fractal dimension of the water system in the study area is between 1.02 and 1.44,which is in the juvenile stage of geomorphological erosion development.The river undercuts strongly,resulting deep valley and the "V" canyon.The northern river has a large slope with strong erosion and large fractal dimension.The southern river has a small slope with relatively weak fluviation,and its fractal dimension is also small.On the one hand,thick loess on the loess hilly region provides a material basis for the development of the geomorphology.On the other hand,the structural uplift of Lyuliang Mountain provides the potential and kinetic conditions for the development and evolution of the rivers,and further shapes the geomorphology.