黄土高原水土流失的地质环境研究

Study on Geological Environment of Soil and Water Loss in Loess Plateau

黄土高原水土流失具有明显的地区差异,但从地质构造来看,多为第三纪或中生代晚期形成的一些构造盆地,早期接受堆积,第四纪地壳运动上升而成为受侵蚀地区。岩性决定着地表的抗蚀性和对水分的保蓄能力,新构造运动为流水侵蚀提供了潜能,二者共同作用,构成影响水土流失的地质背景及内力地质作用的地位。由地质环境的分析表明,水土保持应主要着眼于两个方面:一是改变地表的抗蚀能力和对水分的保蓄能力;二是改变地表的坡度,减小水流的能量。对此提出了相应的水土保持措施。

Soil and water loss in Loess Plateau has an obvious regional difference.The tectonic basin,which was accumulated during the early stage and formed eroded region because of the crustal ascending movement in the Quaternary Period is mainly formed during Tertiary or later Mesozoic,viewing from the geological structure.The lithology decides the corrosion resistance and moisture holding capability of land surface.New tectonic movement provides potential for normal erosion and forms the situation of geological background and geologic function of inner force that affects soil and water loss through the joint influence.It shows through the analysis of geological environment that soil and water conservation should have the following two aspects in mind: a) To improve the corrosion resistance and moisture holding capability of land surface and;b) To alter the gradient of land surface for decreasing the energy of flow.The paper puts forward corresponding measures for soil and water conservation.